As filed with the Securities and Exchange Commission on May 2, 2016April 7, 2021

Registration No. 333-          

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington,WASHINGTON, D.C. 20549

FORM S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Aduro Biotech, Inc.CHINOOK THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

626 Bancroft Way, 3C1600 Fairview Avenue East, Suite 100

Berkeley, California 94710Seattle, WA 98102

(510) 848-4400(206) 485-7051

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Stephen T. IsaacsEric L. Dobmeier

Chairman of the Board, President and Chief Executive Officer

Aduro Biotech,Chinook Therapeutics, Inc.

626 Bancroft Way, 3C1600 Fairview Avenue East, Suite 100

Berkeley, California 94710Seattle, WA 98102

(510) 848-4400(206) 485-7051

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Approximate date of commencement of proposed sale to the public: From time to time after this Registration Statement becomes effective.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box.  ¨box:  ☐

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, as amended other than securities offered only in connection with dividend or interest reinvestment plans, check the following box.  xbox:  ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ¨offering:  ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlierearliest effective registration statement for the same offering.  ¨offering:  ☐

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box.  ¨☐

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D.I. D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box.  ¨☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer” andfiler,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act. (Check one):

CALCULATION OF REGISTRATION FEE

The Registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment thatwhich specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until thisthe registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

EXPLANATORY NOTE

This registration statement contains:contains two prospectuses:

The base prospectus immediately follows this explanatory note. The specific terms of any securities to be offered pursuant to the base prospectus, other than the shares to be issued and sold under the sales agreement, will be specified in a prospectus supplement to the base prospectus. The specific terms of the securities to be issued and sold under the sales agreement are specified in the sales agreement prospectus that immediately follows the base prospectus. The $100,000,000$75,000,000 of common stock that may be offered, issued and sold under the sales agreement prospectus supplement is included in the $300,000,000$275,000,000 of securities that may be offered, issued and sold by usthe registrant under the base prospectus. Upon termination of the sales agreement with the Sales Agreement,Agents, any portion of the $100,000,000$75,000,000 included in the sales agreement prospectus supplement that is not sold pursuant to the Sales Agreement will be available for sale in other offerings pursuant to the base prospectus, and if no shares are sold under the Sales Agreement, the full $100,000,000 of securities may be sold in other offerings pursuant to the base prospectus.

The information contained in this prospectus is not complete and may be changed. These securitiesWe may not be soldsell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities, and it is not soliciting an offer to buy these securities, in any jurisdiction where the offer or sale is not permitted.

Subject to Completion, Dated May 2, 2016SUBJECT TO COMPLETION, DATED April 7, 2021

PROSPECTUS

$300,000,000275,000,000

Common Stock,

Preferred Stock,

Debt Securities, Warrants, Subscription Rights and Units

Warrants

From time to time, we may offer and sell up to $300,000,000$275,000,000 aggregate dollar amount of any combinationshares of the securities described in this prospectus, either individually or in combination. We may also offerour common stock or preferred stock, upon conversion of debt securities, common stock upon conversion of preferred stock, orwarrants to purchase our common stock, preferred stock or debt securities, upon the exercisesubscription rights to purchase our common stock, preferred stock or debt securities and/or units consisting of warrants. We may also authorize onesome or more free writing prospectuses to be provided to you in connection with these offerings.

This prospectus describes some of the general terms that may apply to an offering of our securities. We will provide the specific termsall of these offerings and securities, in any combination, together or separately, in one or more supplements to this prospectus. We may also authorize one or moreofferings, in amounts, at prices and on the terms that we will determine at the time of the offering and which will be set forth in a prospectus supplement and any related free writing prospectuses to be provided to you in connection with these offerings.prospectus. The prospectus supplement and any related free writing prospectus may also add, update or change information contained in this prospectus. The total amount of these securities will have an initial aggregate offering price of up to $275,000,000. You should carefully read this prospectus, the information incorporated, or deemed to be incorporated, by reference in this prospectus, and any applicable prospectus supplement and related free writing prospectus carefully before you invest.

Our common stock is traded on The Nasdaq Global Select Market under the symbol “KDNY.” On April 6, 2021 the last reported sales price for our common stock was $14.83 per share. None of the other securities we may offer are currently traded on any securities exchange. The applicable prospectus supplement and any related free writing prospectus will contain information, where applicable, as well as the documents incorporated by reference, before buyingto any other listing on The Nasdaq Global Select Market or any securities market or exchange of the securities being offered.covered by the prospectus supplement and any related free writing prospectus.

Securities

An investment in our securities involves a high degree of risk. You should carefully consider the information under the heading “Risk Factors” beginning on page 5 of this prospectus before investing in our securities.

Common stock, preferred stock, debt securities, warrants, subscription rights and/or units may be sold by us to or through underwriters or dealers, directly to purchasers or through agents designated from time to time. For additional information on the methods of sale, you should refer to the section titledentitled “Plan of Distribution” in this prospectus and in the applicable prospectus supplement.prospectus. If any underwriters, dealers or agents are involved in the sale of any securities with respect to which this prospectus is being delivered, the names of such underwriters or agents and any applicable fees, discounts or commissions, anddetails regarding over-allotment options, if any, and the net proceeds to us will be set forth in a prospectus supplement. The price to the public of such securities and the net proceeds we expect to receive from such sale will also be set forth in a prospectus supplement.

Our common stock is listed on the NASDAQ Global Select Market under the symbol “ADRO.” On April 27, 2016, the last reported sale price of our common stock on the NASDAQ Global Select Market was $13.66 per share. The applicable prospectus supplement will contain information, where applicable, as to other listings, if any, on the NASDAQ Global Select Market or other securities exchange of the securities covered by the prospectus supplement.

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and in any free writing prospectuses we have authorized for use in connection with a specific offering, and under similar headings in the other documents that are incorporated by reference into this prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is                 , 2016.2021

TABLE OF CONTENTS

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus including theand documents that we incorporateincorporated herein by reference herein, contains, and any applicable prospectus supplement or free writing prospectus includingcontain “forward-looking statements” within the documents we incorporate by reference therein may contain,meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements includinginvolve a number of risks and uncertainties. We caution readers that any forward-looking statement is not a guarantee of future performance and that actual results could differ materially from those contained in the forward-looking statement. These statements regarding ourare based on current expectations of future financial condition, business strategy and plans and objectives of management for future operations. Forward-lookingevents.

Such statements include, allbut are not limited to, statements concerning the following:

In some cases you can identify these statements by forward-looking words such as “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “intend,” “could,” “would,” “project,” “plan,” “expect” or the negative or plural of these words or similar expressions. expressions, in documents incorporated by reference into this prospectus or any free writing prospectus. We intend that such forward-looking statements be subject to the safe harbors created thereby.

These forward-looking statements are based on the current beliefs and expectations of our management and are subject to significant risks and uncertainties. If underlying assumptions prove inaccurate or unknown risks or uncertainties materialize, actual results may differ materially from current expectations and projections. Factors that might cause such a difference include butthose discussed in Part II, Item 1A, “Risk Factors,” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2020, as well as those discussed in this prospectus, the documents incorporated by reference into this prospectus and any free writing prospectus. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this prospectus or, in the case of documents referred to or incorporated by reference, the date of those documents.

All subsequent written or oral forward-looking statements attributable to us or any person acting on our behalf are expressly qualified in their entirety by the cautionary statements contained or referred to in this section. We do not undertake any obligation to release publicly any revisions to these forward-looking statements to reflect events or circumstances after the date of this prospectus or to reflect the occurrence of unanticipated events, except as may be required under applicable U.S. securities law. If we do update one or more forward-looking statements, no inference should be drawn that we will make additional updates with respect to those or other forward-looking statements.

WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a registration statement on Form S-3 under the Securities Act with respect to the securities offered hereby. This prospectus, which constitutes a part of the registration statement, does not contain all of the information set forth in the registration statement, the exhibits filed therewith or the documents incorporated by reference therein. For further information about us and the securities offered hereby, reference is made to the registration statement, the exhibits filed therewith and the documents incorporated by reference therein. Statements contained in this prospectus regarding the contents of any contract or any other document that is filed as an exhibit to the registration statement are not limitednecessarily complete, and in each instance, we refer you to the copy of such contract or other document filed as an exhibit to the registration statement.

We are subject to the informational requirements of the Securities Exchange Act of 1934, as amended, or the Exchange Act and are required to file annual, quarterly and other reports, proxy statements concerningand other information with the following:SEC. The SEC maintains an Internet site (http://www.sec.gov) that contains reports, proxy and information statements, and various other information about us. You may also inspect the documents described herein at our principal executive offices, 1600 Fairview Avenue East, Suite 100 Seattle, WA 98102, during normal business hours.

Information about us is also available at our website at www.chinooktx.com. However, the information on our website is not a part of this prospectus and is not incorporated by reference into this prospectus.

INCORPORATION OF INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” information that we file with the SEC, which means that we can disclose important information to you by referring you to those other documents. The information incorporated by reference is an important part of this prospectus, and information we file later with the SEC will automatically update and supersede this information. A Current Report (or portion thereof) furnished, but not filed, on Form 8-K shall not be incorporated by reference into this prospectus. We incorporate by reference the documents listed below and any future filings we make with the SEC under Section 13(a), 13(c), 14, or 15(d) of the Exchange Act prior to the termination of any offering of securities made by this prospectus:

These statements reflect our current views with respectAll reports; and other documents we subsequently file pursuant to future events and are based on assumptions and are subjectSection 13(a), 13(c), 14 or 15(d) of the Exchange Act prior to risks and uncertainties. Given these uncertainties, you should not place undue reliance on these forward-looking statements. We discuss in greater detail manythe termination of these risks under the heading “Risk Factors” contained in the applicable prospectus supplement, in any free writing prospectusesthis offering, including all such documents we may authorize for use in

connection with a specific offering, and in our most recent annual report on Form 10-K and in our most recent quarterly report on Form 10-Q, as well as any amendments thereto reflected in subsequent filingsfile with the SEC. Also, these forward-looking statements represent our estimates and assumptions only as ofSEC after the date of the document containinginitial registration statement and prior to the applicable statement. Unless required by law, we undertake no obligationeffectiveness of the registration statement, but excluding any information furnished to, update or revise any forward-looking statements to reflect new information or future events or developments. Thus, you should not assume that our silence over time means that actual events are bearing out as expressed or implied in such forward-looking statements. You should read this prospectus, any applicable prospectus supplement, together with the documents we haverather than filed with, the SEC, that arewill also be incorporated by reference in this prospectus and deemed to be part of this prospectus from the date of the filing of such reports and documents.

We will furnish without charge to you, on written or oral request, a copy of any free writingor all of such documents that has been incorporated herein by reference (other than exhibits to such documents unless such exhibits are specifically incorporated by reference into the documents that this prospectus incorporates). Written or oral requests for copies should be directed to Chinook Therapeutics, Inc., Attn: Investor Relations, 1600 Fairview Avenue East, Suite 100 Seattle, WA 98102, and our telephone number is (206) 485-7051. See the section of this prospectus entitled “Where You Can Find More Information” for information concerning how to obtain copies of materials that we may authorize for use in connection with this offering completely andfile with the understandingSEC.

Any statement contained in this prospectus, or in a document, all or a portion of which is incorporated by reference, shall be modified or superseded for purposes of this prospectus to the extent that our actual future results may be materially different from what we expect. We qualify alla statement contained in this prospectus, any prospectus supplement or any document incorporated by reference modifies or supersedes such statement. Any such statement so modified or superseded shall not, except as so modified or superseded, constitute a part of theforward-looking statements in the foregoing documents by these cautionary statements.this prospectus.

USE OF PROCEEDS

Except as describedWe will retain broad discretion over the use of the net proceeds to us from the sale of our securities under this prospectus. Unless otherwise provided in anythe applicable prospectus supplement, or in any free writing prospectuses we have authorized for use in connection with a specific offering, we currently intend to use the net proceeds from the sale of the securities offered by us hereunder, if any,under this prospectus for working capital and general corporate purposes, includingwhich may include funding research, clinical and process development expensesand manufacturing of our product candidates, increasing our working capital, reducing indebtedness, acquisitions or investments in businesses, products or technologies that are complementary to our own and capital expenditures.

The amounts and timing We will set forth in the applicable prospectus supplement our intended use for the net proceeds received from the sale of our useany securities. Pending the application of the net proceeds, we intend to invest the net proceeds in short-term or long-term, investment-grade, interest-bearing securities.

PLAN OF DISTRIBUTION

We may sell the securities covered by this prospectus to one or more underwriters for public offering and sale by them, and may also sell the securities to investors directly or through agents. We will name any underwriter or agent involved in the offer and sale of securities in the applicable prospectus supplement. We have reserved the right to sell or exchange securities directly to investors on our own behalf in jurisdictions where we are authorized to do so. We may distribute the securities from time to time in one or more transactions:

We may directly solicit offers to purchase the securities being offered by this offeringprospectus. We may also designate agents to solicit offers to purchase the securities from time to time. We will dependname in a prospectus supplement any agent involved in the offer or sale of our securities. Unless otherwise indicated in a prospectus supplement, an agent will be acting on a number of factors, suchbest efforts basis, and a dealer will purchase securities as a principal for resale at varying prices to be determined by the timing and progress of our research and development efforts,dealer.

If we utilize an underwriter in the timing and progress of any partnering and commercialization efforts, technological advances and the competitive environment for our products. Assale of the date ofsecurities being offered by this prospectus, we cannot specifywill execute an underwriting agreement with certainty allthe underwriter at the time of sale and we will provide the name of any underwriter in the prospectus supplement that the underwriter will use to make resales of the particular usessecurities to the public. In connection with the sale of the securities, we, or the purchasers of securities for whom the underwriter may act as agent, may compensate the underwriter in the form of underwriting discounts or commissions. The underwriter may sell the securities to or through dealers, and those dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters or commissions from the purchasers for whom they may act as agent.

We will provide in the applicable prospectus supplement any compensation we pay to underwriters, dealers, or agents in connection with the offering of the securities, and any discounts, concessions or commissions allowed by underwriters to participating dealers. Underwriters, dealers and agents participating in the distribution of the securities may be deemed to be underwriters within the meaning of the Securities Act of 1933, as amended, or the Securities Act, and any discounts and commissions received by them and any profit realized by them on resale of the securities may be deemed to be underwriting discounts and commissions. In compliance with the guidelines of the Financial Industry Regulatory Authority, Inc. (“FINRA”), the aggregate maximum discount, commission or agency fees or other items constituting underwriting compensation to be received by any FINRA member or independent broker-dealer shall be fair and reasonable. We may enter into agreements to indemnify underwriters, dealers and agents against civil liabilities, including liabilities under the Securities Act, and to reimburse them for certain expenses. We may grant underwriters who participate in the distribution of our securities under this prospectus an option to purchase additional securities in connection with the distribution.

The securities we offer under this prospectus may or may not be listed through The Nasdaq Global Select Market or any other securities exchange. To facilitate the offering of securities, certain persons participating in the offering may engage in transactions that stabilize, maintain or otherwise affect the price of the securities. This may include short sales of the securities, which involves the sale by persons participating in the offering of more securities than we sold to them. In these circumstances, these persons would cover such short positions by making purchases in the open market or by exercising their option to purchase additional securities. In addition, these persons may stabilize or maintain the price of the securities by bidding for or purchasing securities in the open market or by imposing penalty bids, whereby selling concessions allowed to dealers participating in the offering may be reclaimed if securities sold by them are repurchased in connection with stabilization transactions. The effect of these transactions may be to stabilize or maintain the market price of the securities at a

level above that which might otherwise prevail in the open market. These transactions may be discontinued at any time.

We may engage in at the market offerings into an existing trading market in accordance with Rule 415(a)(4) under the Securities Act. In addition, we may enter into derivative transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement indicates, in connection with those derivatives, the third parties may sell securities covered by this prospectus and the applicable prospectus supplement, including short sale transactions. If so, the third party may use securities pledged by us or borrowed from us or others to settle those sales or to close out any related open borrowings of stock, and they may use securities received from us in settlement of those derivatives to close out any related open borrowings of stock. The third party in these sale transactions will be an underwriter and will be identified in the applicable prospectus supplement. In addition, we may otherwise loan or pledge securities to a financial institution or other third party that in turn may sell the securities short using this prospectus. The financial institution or other third party may transfer its economic short position to investors in our securities or in connection with a concurrent offering of other securities.

We will file a prospectus supplement to describe the terms of any offering of our securities covered by this prospectus. The prospectus supplement will disclose:

We will bear all or substantially all of the costs, expenses and fees in connection with the registration of our securities under this prospectus. The underwriters, dealers and agents may engage in transactions with us, or perform services for us, in the ordinary course of business.

Under Rule 15c6-1 of the Exchange Act, trades in the secondary market generally are required to settle in two business days, unless the parties to any such trade expressly agree otherwise or the securities are sold by us hereunder.to an underwriter in a firm commitment underwritten offering. The applicable prospectus supplement may provide that the original issue date for your securities may be more than two scheduled business days after the trade date for your securities. Accordingly, our managementin such a case, if you wish to trade securities on any date prior to the second business day before the original issue date for your securities, you will have broad discretion in the timing and application of these proceeds. Pending applicationbe required, by virtue of the net proceeds as described above, we intendfact that your securities initially are expected to temporarily investsettle in more than two scheduled business days after the proceeds in short-term, interest-bearing instruments.trade date for your securities, to make alternative settlement arrangements to prevent a failed settlement.

DESCRIPTION OF CAPITAL STOCK

AsGeneral

The following is a summary description of the datematerial terms of this prospectus, our capital stock. The description of capital stock is intended as a summary and is qualified in its entirety by reference to our restated certificate of incorporation, as amended (“certificate of incorporation”), and our amended and restated bylaws, as amended (“bylaws”), copies of which are filed as exhibits to our most recent Annual Report on Form 10-K and are incorporated by reference herein. We encourage you to read our certificate of incorporation, our bylaws and the applicable provisions of the Delaware General Corporation Law, or DGCL, for additional information.

Our certificate of incorporation authorizes us to issue up to 300,000,000 shares of common stock, $0.0001 par value per share, and 10,000,000 shares of preferred stock, $0.0001 par value per share.

As of MarchDecember 31, 2016, 64,559,7722020, there were 42,282,381 shares of our common stock were outstanding, and no shares of preferred stock were outstanding.

The following summary describes the material terms of our capital stock. The description of capital stock is qualified by reference to our certificate of incorporation and our bylaws.

Common Stock

Voting Rights

Each holder of our common stock is entitled to one vote for each share on all matters submitted to a vote of the stockholders, including the election of directors. Under our certificate of incorporation and bylaws, our stockholders do not have cumulative voting rights. Because of this, the holders of a majority of the shares of common stock entitled to vote in any election of directors can elect all of the directors standing for election, if they should so choose.

Dividends

Subject to preferences that may be applicable to any then-outstanding preferred stock, holders of common stock are entitled to receive ratably those dividends, if any, as may be declared from time to time by the board of directors out of legally available funds.

Liquidation

In the event of our liquidation, dissolution or winding up, holders of common stock will be entitled to share ratably in the net assets legally available for distribution to stockholders after the payment of all of our debts and other liabilities and the satisfaction of any liquidation preference granted to the holders of anythen-outstanding shares of preferred stock.

Rights and Preferences

Holders of common stock have no preemptive, conversion or subscription rights and there are no redemption or sinking fund provisions applicable to the common stock. The rights, preferences and privileges of the holders of common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of preferred stock that we may designate and issue in the future.

Preferred Stock

Under our certificate of incorporation, our board of directors is authorized by resolution to divide the preferred stock into series and, with respect to each series, to determine the designations and the powers, preferences and rights, and the qualifications, limitations and restrictions thereof, including the dividend rights, conversion or exchange rights, voting rights, redemption rights and terms, liquidation preferences, sinking fund provisions and the number of shares constituting the series. Our board of directors can, without stockholder approval but subject to the terms of the certificate of incorporation, issue preferred stock with voting and other rights that could adversely affect the voting power of the holders of our common stock and which could have certain anti-takeover effects. Before we may issue any series of preferred stock, our board of directors will be required to adopt resolutions creating and designating such series of preferred stock.

The following summary of terms of our preferred stock is not complete. You should refer to the provisions of our certificate of incorporation and bylaws and the resolutions containing the terms of each class or series of the preferred stock which have been or will be filed with the SEC at or prior to the time of issuance of such class or series of preferred stock and described in the applicable prospectus supplement. The applicable prospectus supplement may also state that any of the terms set forth herein are inapplicable to such series of preferred stock, provided that the information set forth in such prospectus supplement does not constitute material changes to the information herein such that it alters the nature of the offering or the securities offered.

We will fix the designations, voting powers, preferences and rights of the preferred stock of each series we issue under this prospectus, as well as the qualifications, limitations or restrictions thereof, in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering. We will describe in the applicable prospectus supplement the terms of the series of preferred stock being offered, including, to the extent applicable:

If we issue shares of preferred stock under this prospectus, the shares will be fully paid andnon-assessable.

The issuance of preferred stock could adversely affect the voting power of holders of common stock and reduce the likelihood that common stockholders will receive dividend payments and payments upon liquidation. The issuance could have the effect of decreasing the market price of the common stock. The issuance of preferred stock also could have the effect of delaying, deterring or preventing a change in control of us.

Registration Rights

We are party to an amended and restated investors’ rights agreement that provides that holders of our common stock, including certain holders of 5% of our capital stock and entities affiliated with certain of our directors, have certain registration rights, as set forth below. The registration of shares of our common stock pursuant to the exercise of registration rights described below would enable the holders to sell these shares without restriction under the Securities Act when the applicable registration statement is declared effective. We will pay the registration expenses, other than the underwriting discount, of the shares registered pursuant to the demand, piggyback and Form S-3 registrations described below.

Generally, in an underwritten offering, the managing underwriter, if any, has the right, subject to specified conditions, to limit the number of shares such holders may include. The demand, piggyback and Form S-3 registration rights described below will expire upon the earlier April 20, 2020, which is five years following the completion of our initial public offering, or when all investors, considered with their affiliates, can sell all of their shares in a 90-day period under Rule 144.

Demand Registration Rights

Upon the written request of certain of the holders of the registrable securities then outstanding that we file a registration statement under the Securities Act covering the registration of registrable securities having an aggregate offering price to the public of not less than $5.0 million, we will be required to use our best efforts to register all or a portion of their registrable securities that holders may request to be registered. We are not required to effect such registrations on more than two occasions.

Piggyback Registration Rights

In the event that we propose to register any of our securities under the Securities Act in a future offering, either for our own account or for the account of other security holders, the holders of registrable securities will be entitled to certain “piggyback” registration rights allowing them to include their shares in such registration, subject to certain marketing and other limitations. As a result, whenever we propose to file a registration statement under the Securities Act, including a registration statement on Form S-3 as discussed below, other than with respect to a demand registration or a registration statement on Forms S-4 or S-8 or related to stock issued upon conversion of debt securities, the holders of these shares are entitled to notice of the registration and have the right, subject to limitations that the underwriters may impose on the number of shares included in the registration, to include their shares in the registration.

In connection with the filing of the registration statement of which this prospectus forms a part, certain holders of shares of common stock were entitled to, and the necessary percentage of holders waived, their rights to notice of such filing and to include their shares of registrable securities in the registration statement of which this prospectus forms a part.

Form S-3 Registration Rights

The holders of registrable securities are entitled to certain Form S-3 registration rights. Such request for registration on Form S-3 must cover securities the aggregate offering price of which, before payment of the underwriting discount, equals or exceeds $1.5 million.

Anti-Takeover Provisions

Certificate of Incorporation and Bylaws

Because our stockholders do not have cumulative voting rights, our stockholders holding a majority of the outstanding shares of common stock outstanding will be able to elect all of our directors. Our certificate of incorporation and bylaws provide that all stockholder actions must be effected at a duly called meeting of stockholders and not by written consent. A special meeting of stockholders may be called by the chairman of our board of directors, the majority of our whole board of directors, or our chief executive officer.

Our certificate of incorporation provides for our board of directors to be divided into three classes, with staggered three-year terms. As a result, only one class of directors will beis elected at each annual meeting of stockholders, with the other classes continuing for the remainder of their respective three-year terms. Stockholders have no cumulative voting rights, and the stockholders representing a majority of the shares of common stock entitled to vote in any election of directors may elect all of the directors standing for election. In addition, our certificate of incorporation provides that stockholders may remove directors only for cause and only by the affirmative vote of the holders of at least sixty-six and two-thirds percent (66-2/3%) in voting power of our stock entitled to vote thereon.

Our certificate of incorporation further provides that the affirmative vote of holders of at least sixty-six and two-thirds percent (66-2/3%) of the voting power of all of the then outstanding shares of voting stock, voting as a single class, will be required to amend certain provisions of our certificate of incorporation, including provisions relating to the size of the board, removal of directors, special meetings, actions by written consent and cumulative voting. The affirmative vote of holders of at least sixty-six and two-thirds percent (66-2/3%) of the voting power of all of the then outstanding shares of voting stock, voting as a single class, will beis required to amend or repeal our bylaws, although our bylaws may be amended by a simple majority vote of our board of directors.

The foregoing provisions make it more difficult for our existing stockholders to replace our board of directors as well as for another party to obtain control of us by replacing our board of directors. Since our board of directors has the power to retain and discharge our officers, these provisions could also make it more difficult for existing stockholders or another party to effect a change in management. In addition, the authorization of undesignated preferred stock makes it possible for our board of directors to issue preferred stock with voting or other rights or preferences that could impede the success of any attempt to cause a change in control of us.

These provisions are intended to enhance the likelihood of continued stability in the composition of our board of directors and its policies and to discourage certain types of transactions that may involve an actual or threatened acquisition of us. These provisions are also designed to reduce our vulnerability to an unsolicited acquisition proposal and to discourage certain tactics that may be used in proxy fights. However, such provisions could have the effect of discouraging a change of control of our company or changes in our board of directors that our stockholders might consider favorable. As a consequence, these provisions also may inhibit fluctuations in the market price of our stock that could result from actual or rumored takeover attempts.

Section 203 of the Delaware General Corporation Law

We are subject to Section 203 of the Delaware General Corporation Law,DGCL, which prohibits a Delaware corporation from engaging in anya business combination with any interested stockholder for a period of three years afterfollowing the date that such stockholderthe person became an interested stockholder, (as defined below), with the following exceptions:

In general, Section 203 of the DGCL defines business combination to include the following:

In general, Section 203 of the DGCL defines an “interested stockholder” as an entity or person who, together with the entity’s or person’s affiliates and associates, beneficially owns, or is an affiliate of the corporation and within three years prior to the time of determination of interested stockholder status did own, 15% or more of the outstanding voting stock of the corporation.

A Delaware corporation may “opt out” of these provisions with an express provision in its certificate of incorporation. We have not opted out of these provisions, which may as a result, discourage or prevent mergers or other takeover or change of control attempts of our company.us.

Choice of Forum

Our certificate of incorporation provides that the Court of Chancery of the State of Delaware will be the exclusive forum for any derivative action or proceeding brought on our behalf; any action asserting a breach of fiduciary duty; any action asserting a claim against us arising pursuant to the Delaware General Corporation Law,DGCL, our certificate of incorporation or our bylaws; or any action asserting a claim against us that is governed by the internal affairs doctrine.

Listing

Our common stock The enforceability of similar choice of forum provisions in other companies’ certificates of incorporation has been challenged in legal proceedings and it is listedpossible that a court could find these types of provisions to be inapplicable or unenforceable. Similarly, our bylaws provide that (a) the Court of Chancery of the State of Delaware will be the sole and exclusive forum for any derivative action or proceeding brought on our behalf; any action asserting a breach of fiduciary duty; any action asserting a claim against us arising pursuant to the NASDAQ Global Select MarketDGCL; or any action asserting a claim against us that is governed by the internal affairs doctrine, and (b) the federal district courts of the United Stated of America are the exclusive forum for the resolution of any complaint asserting a cause of action arising under the symbol “ADRO.”Securities Act of 1933, as amended. Although our bylaws contain the choice of forum provision described above, it is possible that a court could find that such provisions are inapplicable for a particular claim or action or that such provisions are unenforceable.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Computershare Trust Company, N.A. The transfer agent and registrar’s address is 250 Royall Street, Canton, Massachusetts 02021.

Exchange Listing

Our common stock is listed on the Nasdaq Global Select Market under the symbol “KDNY.”

DESCRIPTION OF DEBT SECURITIES

General

We maywill issue the debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. While the terms we have summarized below will apply generally to any debt securities that we may offer underoffered by this prospectus we will describeand any accompanying prospectus supplement under an indenture to be entered into between us and the particular terms of any debt securities that we may offer in more detailtrustee identified in the applicable prospectus supplement. The terms of any debt securities offered under a prospectus supplement may differ from the terms described below. Unless the context requires otherwise, whenever we refer to the indenture, we also are referring to any supplemental indentures that specify the terms of a particular series of debt securities.

We will issue the debt securities underwill include those stated in the indenture that we will enter into withand those made part of the trustee named in the indenture. The indenture will be qualified underby reference to the Trust Indenture Act of 1939, as amended, orin effect on the Trust Indenture Act.date of the indenture. We have filed a copy of the form of indenture as an exhibit to the registration statement ofin which this prospectus is a part,included. The indenture will be subject to and supplemental indentures and forms of debt securities containinggoverned by the terms of the debt securities being offered will be filed as exhibits toTrust Indenture Act of 1939. Unless otherwise specified in the registration statement of which thisapplicable prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

The following summary of material provisions ofsupplement, the debt securities will represent our direct, unsecured obligations and the indenture is subject to, and qualified in its entirety by reference to,will rank equally with all of the provisions of the indenture applicable to a particular series of debt securities. our other unsecured indebtedness.

We urge you to read the applicable prospectus supplements and any related free writing prospectuses related to the debt securities that we may offer under this prospectus as well as the complete indenture that contains the terms of the debt securities.

General

The indenture does not limit theup to an aggregate principal amount of $275,000,000 in debt securities, that we may issue. It provides that we may issueor if debt securities up toare issued at a discount, or in a foreign currency, foreign currency units or composite currency, the principal amount that we may authorize andas may be in any currency or currency unit that we may designate. Exceptsold for the limitations on consolidation, merger and salean aggregate public offering price of all or substantially all of our assets contained in the indenture, the terms of the indenture do not contain any covenants or other provisions designedup to give holders of any debt securities protection against changes in our operations, financial condition or transactions involving us.

$275,000,000. We may issue the debt securities issued underin one or more series with the indenturesame or various maturities, at par, at a premium, or at a discount. We will describe the particular terms of each series of debt securities in a prospectus supplement relating to that series, which we will file with the SEC. The prospectus supplement relating to the particular series of debt securities being offered will specify the particular amounts, prices and terms of those debt securities. These terms may include:

We may issue discount debt securities that are not issued at a discount, mayprovide for an amount less than the stated principal amount to be issueddue and payable upon acceleration of the maturity of such debt securities in accordance with “original issue discount,” or OID, for U.S. federal income tax purposes because of interest payment and other characteristics orthe terms of the indenture. We may also issue debt securities. Materialsecurities in bearer form, with or without coupons. If we issue discount debt securities or debt securities in bearer form, we will describe material U.S. federal income tax considerations applicableand other material special considerations which apply to these debt securities issued with OID will be described in more detail in anythe applicable prospectus supplement.

We may issue debt securities denominated in or payable in a foreign currency or currencies or a foreign currency unit or units. If we do, we will describe the restrictions, elections, and general tax considerations relating to the debt securities and the foreign currency or currencies or foreign currency unit or units in the applicable prospectus supplement.

Debt securities offered under this prospectus and any prospectus supplement will be subordinated in right of payment to certain of our outstanding senior indebtedness. In addition, we will seek the consent of the holders of any such senior indebtedness prior to issuing any debt securities under this prospectus to the extent required by the agreements evidencing such senior indebtedness.

Registrar and Paying Agent

The debt securities may be presented for registration of transfer or for exchange at the corporate trust office of the security registrar or at any other office or agency that we maintain for those purposes. In addition, the debt securities may be presented for payment of principal, interest and any premium at the office of the paying agent or at any office or agency that we maintain for those purposes.

Conversion or Exchange Rights

Debt securities may be convertible into or exchangeable for shares of our common stock. The terms and conditions of conversion or exchange will be stated in the applicable prospectus supplement. The terms will include, among others, the following:

Registered Global Securities

If we decide to issue debt securities in the form of one or more global securities, then we will register the global securities in the name of the depositary for the global securities or the nominee of the depositary, and the global securities will be delivered by the trustee to the depositary for credit to the accounts of the holders of beneficial interests in the debt securities.

The prospectus supplement will describe the specific terms of the depositary arrangement for debt securities of a series that are issued in global form. None of us, the trustee, any payment agent or the security registrar will have any responsibility or liability for any aspect of the records relating to or payments made on account of beneficial ownership interests in a global debt security or for maintaining, supervising or reviewing any records relating to these beneficial ownership interests.

No Protection in the Event of Change of Control

The indenture does not have any covenants or other provisions providing for a put or increased interest or otherwise that would afford holders of our debt securities additional protection in the event of a recapitalization transaction, a change of control or a highly leveraged transaction. If we offer any covenants or provisions of this type with respect to any debt securities covered by this prospectus, we will describe them in the applicable prospectus supplement.

Covenants

Unless otherwise indicated in this prospectus or the applicable prospectus supplement, our debt securities will not have the benefit of any covenants that limit or restrict our business or operations, the pledging of our assets or the incurrence by us of indebtedness. We will describe in the applicable prospectus supplement the termsany material covenants in respect of thea series of debt securities being offered, including:securities.

Merger, Consolidation or Sale of Assets

The form of indenture provides that we will not consolidate with or merge into any other person or convey, transfer, sell or lease our properties and assets substantially as an entirety to any person, unless:

•

whether interest will be payable in cash or additional debt securities at our or the holders’ option and the terms and conditions upon which the election may be made;

Conversion or Exchange Rights

We will set forthUnless otherwise specified in the applicable prospectus supplement, the terms on which a series of debt securities mayfollowing events will be convertible into or exchangeable for our common stock or our other securities. We will include provisions as to settlement upon conversion or exchange and whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock or our other securities that the holders of the series of debt securities receive would be subject to adjustment.

Consolidation, Merger or Sale

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the indenture will not contain any covenant that restricts our ability to merge or consolidate, or sell, convey, transfer or otherwise dispose of our assets as an entirety or substantially as an entirety. However, any successor to or acquirer of such assets (other than a subsidiary of ours) must assume all of our obligations under the indenture or the debt securities, as appropriate.

Events of Default under the Indenture

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the following are events of default under the indenture with respect to any series of debt securities that we may issue:

If an event of default with respect to debt securities of any series occurs and is continuing,series:

The trustee may withhold notice to usthe holders of the debt securities of any series of any default, except in writing, and to the trustee if notice is given by such holders, may declare the unpaidpayment of principal of or premium, if any, and accruedor interest on the debt securities of a series, if any, due and payable immediately. the trustee considers it to be in the best interest of the holders of the debt securities of that series to do so.

If an event of default specified(other than an event of default resulting from certain events of bankruptcy, insolvency or reorganization) occurs, and is continuing, then the trustee or the holders of not less than 25% in aggregate principal amount of the last bullet point aboveoutstanding debt securities of any series may accelerate the maturity of the debt securities. If this happens, the entire principal amount, plus the premium, if any, of all the outstanding debt securities of the affected series plus accrued interest to the date of acceleration will be immediately due and payable. At any time after the acceleration, but before a judgment or decree based on such acceleration is obtained by the trustee, the holders of a majority in aggregate principal amount of outstanding debt securities of such series may rescind and annul such acceleration if:

In addition, if the acceleration occurs with respectat any time when we have outstanding indebtedness that is senior to us,the debt securities, the payment of the principal amount of and accrued interest, ifoutstanding debt securities may be subordinated in right of payment to the prior payment of any of each issueamounts due under the senior indebtedness, in which case the holders of debt securities then outstanding shallwill be entitled to payment under the terms prescribed in the instruments evidencing the senior indebtedness and the indenture.

If an event of default resulting from certain events of bankruptcy, insolvency or reorganization occurs, the principal, premium and interest amount with respect to all of the debt securities of any series will be due and payable immediately without any noticedeclaration or other actionact on the part of the trustee or any holder.the holders of the debt securities of that series.

The holders of a majority in principal amount of the outstanding debt securities of an affected series may waive any default or event of default with respect to the series and its consequences, except defaults or events of default regarding payment of principal, premium, if any, or interest, unless we have cured the default or event of default in accordance with the indenture. Any waiver shall cure the default or event of default.

Subject to the terms of the indenture, if an event of default under an indenture shall occur and be continuing, the trustee will be under no obligation to exercise any of its rights or powers under such indenture at the request or direction of any of the holders of the applicable series of debt securities, unless such holders have offered the trustee reasonable indemnity. The holders of a majority in principal amount of the outstanding debt securities of any series will have the right to waive any existing default or compliance with any provision of the indenture or the debt securities of that series and to direct the time, method and place of conducting any proceeding for any remedy available to the trustee, or exercisingsubject to certain limitations specified in the indenture.

No holder of any trust or power conferred on the trustee,debt security of a series will have any right to institute any proceeding with respect to the indenture or for any remedy under the indenture, unless:

These limitations do not apply to a suit instituted by a holder of debt securities if we default in the payment of the principal, premium, if any, or interest on, the debt securities.

We will periodically file statements with the trustee regarding our compliance with specified covenants in the indenture.

Modification of Indenture; Waiver

We and the trustee may change an indenture without the consent of any holders with respect to specific matters:

•

to comply with the provisions described above under “Description of Debt Securities—Consolidation, Merger or Sale;”

In addition, under the indenture, the rights of holders of a series of debt securities may be changed by us and the trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of eachthe affected series that is affected. However, unless we provide otherwisedo not give the trustee a direction inconsistent with such request during such 60-day period.

DischargeDefeasance of Debt Securities and Certain Covenants in Certain Circumstances

EachThe indenture provides that we canpermits us, at any time, to elect to be discharged fromdischarge our obligations with respect to one or more series of debt securities by following certain procedures described in the indenture. These procedures will allow us either:

•

recover excess money held by the trustee;

In order to exercise our rights to be discharged,either defeasance option, we must irrevocably deposit with the trustee or other qualifying trustee, in trust for that purpose:

that, in each case specified above, provides a sufficient amount to pay all the principal of, any premium, if any, and interest, if any, on the debt securities of the series, on the scheduled due dates paymentsor on a selected date of redemption in accordance with the terms of the indenture.

In addition, defeasance may be effected only if, among other things:

Form, ExchangeIf we fail to comply with our remaining obligations under the indenture and Transfer

We will issueapplicable supplemental indenture after a covenant defeasance of the indenture and applicable supplemental indenture, and the debt securities are declared due and payable because of the occurrence of any undefeased event of default, the amount of money and/or U.S. Government Obligations and/or Foreign Government Obligations on deposit with the trustee could be insufficient to pay amounts due under the debt securities of eachthe affected series onlyat the time of acceleration. We will, however, remain liable in fully registered form without coupons and, unless we provide otherwiserespect of these payments.

The term “U.S. Government Obligations” as used in the applicable prospectus supplement, in denominations of $1,000 and any integral multiple thereof. The indenture provides that we may issue debt securities of a series in temporary or permanent global form and as book-entryabove discussion means securities that will be deposited with,are direct obligations of or on behalfnon-callable obligations guaranteed by the United States of America for the payment of which obligation or guarantee the full faith and credit of the United States of America is pledged.

The Depository Trust Company, or DTC, or another depositary named by us and identifiedterm “Foreign Government Obligations” as used in the applicable prospectus supplementabove discussion means, with respect to that series. To the extent the debt securities of a series are issued in global form and as book-entry, a description of terms relating to any book-entry securities will be set forth in the applicable prospectus supplement.

At the option of the holder, subject to the terms of the indenture and the limitations applicable to global securities described in the applicable prospectus supplement, the holder of the debt securities of any series can exchangethat are denominated in a currency other than U.S. dollars, (1) direct obligations of the government that issued or caused to be issued such currency for the payment of which obligations its full faith and credit is pledged or (2) obligations of a person controlled or supervised by or acting as an agent or instrumentality of such government the timely payment of which is unconditionally guaranteed as a full faith and credit obligation by that government, which in either case under clauses (1) or (2), are not callable or redeemable at the option of the issuer.

Regarding the Trustee

We will identify the trustee with respect to any series of debt securities for other debt securities ofin the same series, in any authorized denomination and of like tenor and aggregate principal amount.

Subjectprospectus supplement relating to the termsapplicable debt securities. You should note that if the trustee becomes a creditor of ours, the indenture and the limitations applicableTrust Indenture Act of 1939 limit the rights of the trustee to global securities set forthobtain payment of claims in certain cases, or to realize on certain property received in respect of any such claim, as security or otherwise. The trustee and its affiliates may engage in, and will be permitted to continue to engage in, other transactions with us and our affiliates. If, however, the applicable prospectus supplement,trustee acquires any “conflicting interest” within the meaning of the Trust Indenture Act of 1939, it must eliminate such conflict or resign.

The holders of the debt securities may present the debt securities for exchange or for registration of transfer, duly endorsed or with the form of transfer endorsed thereon duly executed if so required by us or the security registrar, at the officea majority in principal amount of the security registrar or at the office of any transfer agent designated by us for this purpose. Unless otherwise provided in the debt securities that the holder presents for transfer or exchange, we will impose no service charge for any registration of transfer or exchange, but we may require payment of any taxes or other governmental charges.

We will name in the applicable prospectus supplement the security registrar, and any transfer agent in addition to the security registrar, that we initially designate for any debt securities. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for the debt securities of each series.

If we elect to redeem thethen outstanding debt securities of any series we will not be required to:

Information Concerningmay direct the Trustee

The trustee, other than duringtime, method and place of conducting any proceeding for exercising any remedy available to the occurrence and continuance oftrustee. If an event of default under an indenture, undertakes to perform only those duties as are specifically set forthoccurs and is continuing, the trustee, in the applicable indenture. Upon

an eventexercise of default under an indenture, the trusteeits rights and powers, must use the same degree of care asand skill of a prudent person would exercise or use in the conduct of his or her own affairs. Subject to thisthat provision, the trustee iswill be under no obligation to exercise any of theits rights or powers given it byunder the indenture at the request of any holder of the holders of the debt securities, unless it isthey have offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur.

Payment and Paying Agents

Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt securities on any interest payment date to the persontrustee reasonable indemnity or security.

No Individual Liability of Incorporators, Stockholders, Officers or Directors

Each indenture provides that no incorporator and no past, present or future stockholder, officer or director of our company or any successor corporation in whose namethose capacities will have any individual liability for any of our obligations, covenants or agreements under the debt securities or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.

We will pay principal of and any premium and interest on the debt securities of a particular series at the office of the paying agents designated by us, except that unless we otherwise indicate in the applicable prospectus supplement, we will make interest payments by check that we will mail to the holder or by wire transfer to certain holders. Unless we otherwise indicate in the applicable prospectus supplement, we will designate the corporate trust office of the trustee as our sole paying agent for payments with respect to debt securities of each series. We will name in the applicable prospectus supplement any other paying agents that we initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for the debt securities of a particular series.

All money we pay to a paying agent or the trustee for the payment of the principal of or any premium or interest on any debt securities that remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the debt security thereafter may look only to us for payment thereof.indenture.

Governing Law

The indentureindentures and the debt securities will be governed by and construed in accordance with the internal laws of the State of New York, except to the extent that the Trust Indenture Act of 1939 is applicable.

DESCRIPTION OF WARRANTS

The following description, together with the additional information we may include in any applicable prospectus supplement and free writing prospectus, summarizes the material terms and provisions of the warrants that we may offer under this prospectus, which may consist of warrants to purchase common stock, preferred stock and/or debt securities and may be issued in one or more series. Warrants may be offered independently or in combination with common stock, preferred stock or debt securities offered by any prospectus supplement. While the terms we have summarized below will apply generally to any warrants that we may offer under this prospectus, we will describe the particular terms of any series of warrants in more detail in the applicable prospectus supplement. The following description of warrants will apply to the warrants offered by this prospectus unless we provide otherwise in the applicable prospectus supplement. The applicable prospectus supplement for a particular series of warrants may specify different or additional terms.

We have filed forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants that may be offered as exhibits to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant and/or the warrant agreement and warrant certificate, as applicable, that contain the terms of the particular series of warrants we are offering, and any supplemental agreements, before the issuance of such warrants. The following summaries of material terms and provisions of the warrants are subject to, and qualified in their entirety by reference to, all the provisions of the form of warrant and/or the warrant agreement and warrant certificate, as applicable, and any supplemental agreements applicable to a particular series of warrants that we may offer under this prospectus. We urge you to read the applicable prospectus supplement related to the particular series of warrants that we may offer under this prospectus, as well as any related free writing prospectus, and the complete form of warrant and/or the warrant agreement and warrant certificate, as applicable, and any supplemental agreements, that contain the terms of the warrants.

General

We will describe in the applicable prospectus supplement the terms of the series of warrants being offered, including, to the extent applicable:

•

the dates on which the right to exercise the warrants will commence and expire;

Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including:

Exercise of Warrants

Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. The warrants may be exercised as set forth in the prospectus supplement relating to the warrants offered. Unless we otherwise specify in the applicable prospectus supplement, warrants may be exercised at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.

Upon receipt of payment and the warrant or warrant certificate, as applicable, properly completed and duly executed at the corporate trust office of the warrant agent, if any, or any other office, including ours, indicated in the prospectus supplement, we will, as soon as practicable, issue and deliver the securities purchasable upon such exercise. If less than all of the warrants (or the warrants represented by such warrant certificate) are exercised, a new warrant or a new warrant certificate, as applicable, will be issued for the remaining warrants.

Governing Law

Unless we provide otherwise in the applicable prospectus supplement, the warrants and warrant agreements, and any claim, controversy or dispute arising under or related to the warrants or warrant agreements, will be governed by, and construed in accordance with, the laws of the State of New York.

DESCRIPTION OF WARRANTS

General

We may issue warrants for the purchase of Rights by Holdersour debt securities, preferred stock, common stock, or any combination thereof. Warrants may be issued independently or together with our debt securities, preferred stock or common stock and may be attached to or separate from any offered securities. Each series of Warrants

Eachwarrants will be issued under a separate warrant agreement to be entered into between us and a bank or trust company, as warrant agent. The warrant agent if any, will act solely as our agent underin connection with the applicablewarrants. The warrant agreement andagent will not assumehave any obligation or relationship of agency or trust for or with any holder of any warrant. A single bankholders or trust company may act as warrant agent for more than one issuebeneficial owners of warrants. A warrant agent will have no duty or responsibility in caseThis summary of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a warrant may, without the consentcertain provisions of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon exercise of, its warrants.

LEGAL OWNERSHIP OF SECURITIES

We can issue securities in registered form or in the form of one or more global securities. We describe global securities in greater detail below. We refer to those persons who have securities registered in their own names on the books that we or any applicable trustee, depositary or warrant agent maintain for this purpose as the “holders” of those securities. These persons are the legal holders of the securities. We refer to those persons who, indirectly through others, own beneficial interests in securities that arewarrants is not registered in their own names, as “indirect holders” of those securities. As we discuss below, indirect holders are not legal holders, and investors in securities issued in book-entry form or in street name will be indirect holders.

Book-Entry Holders

We may issue securities in book-entry form only, as we will specify in the applicable prospectus supplement. This means securities may be represented by one or more global securities registered in the name of a financial institution that holds them as depositary on behalf of other financial institutions that participate in the depositary’s book-entry system. These participating institutions, which are referred to as participants, in turn, hold beneficial interests in the securities on behalf of themselves or their customers.

Only the person in whose name a security is registered is recognized as the holder of that security. Securities issued in global form will be registered in the name of the depositary or its participants. Consequently, for securities issued in global form, we will recognize only the depositary as the holder of the securities, and we will make all payments on the securities to the depositary. The depositary passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depositary and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so undercomplete. For the terms of the securities.

As a result, investors in a global security will not own securities directly. Instead, they will own beneficial interests in a global security, through a bank, broker or other financial institution that participates in the depositary’s book-entry system or holds an interest through a participant. As long as the securities are issued in global form, investors will be indirect holders, and not legal holders, of the securities.

Street Name Holders

We may terminate a global security or issue securities in non-global form. In these cases, investors may choose to hold their securities in their own names or in “street name.” Securities held by an investor in street name would be registered in the name of a bank, broker or other financial institution that the investor chooses, and the investor would hold only a beneficial interest in those securities through an account he or she maintains at that institution.

For securities held in street name, we or any applicable trustee or depositary will recognize only the intermediary banks, brokers and other financial institutions in whose names the securities are registered as the holders of those securities, and we or any applicable trustee or depositary will make all payments on those securities to them. These institutions pass along the payments they receive to their customers who are the beneficial owners, but only because they agree to do so in their customer agreements or because they are legally required to do so. Investors who hold securities in street name will be indirect holders, not holders, of those securities.

Legal Holders

Our obligations, as well as the obligations of any applicable trustee and of any third parties employed by us or a trustee, run only to the legal holders of the securities. We do not have obligations to investors who hold beneficial interests in global securities, in street name or by any other indirect means. This will be the case whether an investor chooses to be an indirect holder of a security or has no choice because we are issuing the securities only in global form.

For example, once we make a payment or give a notice to the legal holder, we have no further responsibility for the payment or notice even if that legal holder is required, under agreements with its participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, we may want to obtain the approval of the legal holders to amend an indenture, to relieve us of the consequences of a default or of our obligation to comply with a particular provisionseries of the indenture or for other purposes. In such an event, we would seek approval only from the holders, and not the indirect holders, of the securities. Whether and how the legal holders contact the indirect holders is up to the legal holders.

Special Considerations for Indirect Holders

If you hold securities through a bank, broker or other financial institution, either in book-entry form because the securities are represented by one or more global securities or in street name,warrants, you should check with your own institutionrefer to find out:

Global Securities

A global security is a security that represents one or any other number of individual securities held by a depositary. Generally, all securities represented by the same global securities will have the same terms.

Each security issued in book-entry form will be represented by a global security that we issue to, deposit with and register in the name of a financial institution or its nominee that we select. The financial institution that we select for this purpose is called the depositary. Unless we specify otherwise in the applicable prospectus supplement, DTC will be the depositary for all securities issued in book-entry form.

A global security may not be transferred to or registered in the name of anyone other than the depositary, its nominee or a successor depositary, unless special termination situations arise. We describe those situations below under “Special Situations When a Global Security Will Be Terminated.” As a result of these arrangements, the depositary, or its nominee, will be the sole registered owner and legal holder of all securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of an account with a broker, bank or other financial institution that in turn has an account with the depositary or with another institution that does. Thus, an investor whose security is represented by a global security will not be a legal holder of the security, but only an indirect holder of a beneficial interest in the global security.

If the prospectus supplement for athat series of warrants and the warrant agreement for that particular security indicates that the security will be issued in global form only, then the security will be represented by a global security at all times unless and until the global security is terminated. If termination occurs, we may issue the securities through another book-entry clearing system or decide that the securities may no longer be held through any book-entry clearing system.

Special Considerations for Global SecuritiesDebt Warrants

The rights of an indirect holderprospectus supplement relating to a global security will be governed by the account rulesparticular issue of the investor’s financial institution and of the depositary, as well as general laws relatingwarrants to purchase debt securities transfers. We do not recognize an indirect holder as a holder of securities and instead deal only with the depositary that holds the global security.

If securities are issued only in the form of a global security, an investor should be aware of the following:

There may be more than one financial intermediary in the chain of ownership for an investor. We do not monitor and are not responsible for the actions of any of those intermediaries.

Special Situations When a Global Security Will Be Terminated

In a few special situations described below, the global security will terminate and interests in it will be exchanged for physical certificates representing those interests. After that exchange, the choice of whether to hold securities directly or in street name will be up to the investor. Investors must consult their own banks, brokers or other financial institutions to find out how to have their interests in securities transferred to their own name, so that they will be direct holders. We have described the rights of holders and street name investors above.

Unless we provide otherwise in the applicable prospectus supplement, the global security will terminate when the following special situations occur:

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if we notify any applicable trustee that we wish to terminate that global security; or

The prospectus supplement may also list additional situations for terminating a global security that would apply only to the particular series of securities covered by the applicable prospectus supplement. When a global security terminates, the depositary, and not we or any applicable trustee, is responsible for deciding the names of the institutions that will be the initial direct holders.

PLAN OF DISTRIBUTION

We may sell the securities from time to time pursuant to underwritten public offerings, direct sales to the public, “at the market” offerings, negotiated transactions, block trades or a combination of these methods. We may sell the securities to or through underwriters or dealers, through agents, or directly to one or more purchasers. We may distribute securities from time to time in one or more transactions:

A prospectus supplement or supplements (and any related free writing prospectus that we may authorize to be provided to you) will describe the terms of the debt warrants, including the following:

Debt warrant certificates will be exchangeable for new debt warrant certificates of different denominations. Debt warrants may be exercised at the corporate trust office of the warrant agent or any other office indicated in

the prospectus supplement. Prior to the exercise of their debt warrants, holders of debt warrants will not have any of the rights of holders of the debt securities purchasable upon exercise and will not be entitled to payment of principal or any premium, if any, or interest on the debt securities purchasable upon exercise.

Equity Warrants

The prospectus supplement relating to a particular series of warrants to purchase our common stock or preferred stock will describe the terms of the warrants, including the following:

Holders of equity warrants will not be entitled:

DESCRIPTION OF SUBSCRIPTION RIGHTS

We may issue subscription rights to purchase our common stock, preferred stock or debt securities. These subscription rights may be offered independently or together with any other security offered hereby and may or may not be transferable by the stockholder receiving the subscription rights in such offering. In connection with any offering of subscription rights, we may enter into a standby arrangement with one or more underwriters or other purchasers pursuant to which the underwriters or other purchasers may be required to purchase any securities remaining unsubscribed for after such offering.

The prospectus supplement relating to any subscription rights we offer, if any, will, to the extent applicable:applicable, include specific terms relating to the offering, including some or all of the following:

The obligations of the underwriters to purchase the securities will be subject to the conditions set forthdescription in the applicable underwriting agreement. prospectus supplement of any subscription rights we offer will not necessarily be complete and will be qualified in its entirety by reference to the applicable subscription rights certificate, which will be filed with the SEC if we offer subscription rights. We urge you to read the applicable subscription rights certificate and any applicable prospectus supplement in their entirety.

DESCRIPTION OF UNITS

We may offer the securities to the public through underwriting syndicates represented by managing underwritersissue units consisting of some or by underwriters without a syndicate. Subject to certain conditions, the underwriters will be obligated to purchase all of the securities offered by the prospectus supplement, other than securities covered bydescribed above, in any over-allotment combination, including common stock, preferred stock, warrants and/or other option. Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may change from time to time. We may use underwriters with whom we have a material relationship. Wedebt securities. The terms of these units will describe in the prospectus supplement, naming the underwriter, the nature of any such relationship.

We may sell securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities and we will describe any commissions we will pay the agent in the prospectus supplement. Unless the prospectus supplement states otherwise, our agent will act on a best-efforts basis for the period of its appointment.

We may authorize agents or underwriters to solicit offers by certain types of institutional investors to purchase securities from us at the public offering pricebe set forth in a prospectus supplement. The description of the terms of these units in the related prospectus supplement pursuantwill not be complete. You should refer to delayed

delivery contracts providingthe applicable form of unit and unit agreement for payment and delivery on a specified date in the future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement.

We may provide agents and underwriters with indemnification against civil liabilities, including liabilities under the Securities Act, or contribution with respect to payments that the agents or underwriters may makecomplete information with respect to these liabilities. Agents and underwriters may engage in transactions with, or perform services for, us in the ordinary course of business.units.

LEGAL MATTERS

Unless otherwise indicated in the applicable prospectus supplement, CooleyFenwick & West LLP, Palo Alto, California,Seattle, Washington, will pass upon the validity of the securities offered by this prospectus and any supplement thereto. As of the date of this prospectus, attorneys with Cooley LLP participating in the preparation of this prospectus and the related Registration Statement on Form S-3 beneficially ownissue an aggregate of 8,500 shares of our common stock. Additionalopinion about certain legal matters may be passed upon for us or anywith respect to the securities. Any underwriters dealers or agents will be advised about legal matters relating to any offering by counsel that we name in the applicable prospectus supplement.their own counsel.

EXPERTS

The consolidated financial statements incorporated in this prospectusProspectus by reference fromto the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 have been audited by Deloitte & Toucheso incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, as stated in their report, which is incorporated herein by reference. Such financial statements have been so incorporated in reliance upongiven on the reportauthority of suchsaid firm given upon their authority as experts in accountingauditing and auditing.accounting.

This prospectus is part of a registration statement we filed with the SEC. This prospectus does not contain all of the information set forth in the registration statement and the exhibits to the registration statement. For further information with respect to us and the securities we are offering under this prospectus, we refer you to the registration statement and the exhibits and schedules filed as a part of the registration statement. Neither we nor any agent, underwriter or dealer has authorized any person to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information in this prospectus is accurate as of any date other than the date on the front page of this prospectus, regardless of the time of delivery of this prospectus or any sale of the securities offered by this prospectus.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read and copy any document we file with the SEC at the SEC’s public reference room at 100 F Street, N.E., Washington, D.C., 20549. Please call the SEC at 1.800.SEC.0330 for further information on the operation of the public reference room. Our SEC filings are also available to the public at the SEC’s website at http://www.sec.gov.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” the information we file with it, which means that we can disclose important information to you by referring you to those documents instead of having to repeat the information in this prospectus. The information incorporated by reference is considered to be part of this prospectus, and later information that we file with the SEC will automatically update and supersede this information. We incorporate by reference the documents listed below and any future filings (including those made after the date of the initial filing of the registration statement of which this prospectus is a part and prior to the effectiveness of such registration statement) we will make with the SEC under Sections 13(a), 13(c), 14, or 15(d) of the Exchange Act until the termination of the offering of the shares covered by this prospectus (other than information furnished under Item 2.02 or Item 7.01 of Form 8-K):

$275,000,000

Common Stock

Preferred Stock

Debt Securities

Warrants

Subscription Rights

Units

PROSPECTUS

Aduro Biotech, Inc.

626 Bancroft Way, 3C, 2021

Berkeley, California 94710

Attn: Investor Relations

This prospectus is part of a registration statement we filed with the SEC. That registration statement and the exhibits filed along with the registration statement contain more information about us and the shares in this offering. Because information about documents referred to in this prospectus is not always complete, you should read the full documents which are filed as exhibits to the registration statement. You may read and copy the full registration statement and its exhibits at the SEC’s public reference rooms or its website.

The information contained in this prospectus is not complete and may be changed. These securitiesWe may not be soldsell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities, and it is not soliciting an offer to buy these securities, in any jurisdiction where the offer or sale is not permitted.

Subject to Completion, Dated May 2, 2016SUBJECT TO COMPLETION, DATED April 7, 2021

PROSPECTUS

$100,000,000Up to $75,000,000

Common Stock

We have entered into a certain Sales Agreement, or sales agreement (the “Sales Agreement”) with Cowen and Company,SVB Leerink LLC, or Cowen,SVB Leerink, and Cantor Fitzgerald & Co., or Cantor Fitzgerald, and, together, the Sales Agents, relating to shares of our common stock offered by this prospectus. In accordance with the terms of the sales agreement, we may offer and sell shares of our common stock having an aggregate offering price of up to $100$75.0 million from time to time through Cowen.or to the Sales Agents, acting as our agents or principals.

Our common stock is listedtraded on the NASDAQThe Nasdaq Global Select Market under the symbol “ADRO.“KDNY.” On April 27, 2016, theThe last reported salesales price of our common stock on the NASDAQThe Nasdaq Global Select Market on April 6, 2021 was $13.66$14.83 per share.

Sales of our common stock, if any, under this prospectus may be made in sales deemed to be an “at the market offerings”offering” as defined in Rule 415415(a)(4) promulgated under the Securities Act of 1933, as amended, or the Securities Act, including sales made directly on or through the NASDAQ Global Select Market, the existing trading market for our common stock, sales made to or through a market maker other than on an exchange or otherwise, in negotiated transactions at market prices prevailing at the time of sale or at prices related to such prevailing market prices, and/or any other method permitted by law. Cowen isAct. The Sales Agents are not required to sell any specific number or dollar amount of securities, but will act as a sales agentagents using commercially reasonable efforts consistent with itstheir normal trading and sales practices, on mutually agreed terms between Cowenthem and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.

The compensation to Cowenthe Sales Agents for sales of common stock sold pursuant to the sales agreement will be an amountequal to up to 3%3.0% of the aggregate gross proceeds of any shares of common stock sold under the sales agreement. In connection with the sale of the common stock on our behalf, Coweneach Sales Agent will be deemed to be an “underwriter” within the meaning of the Securities Act and the compensation of Cowenthe Sales Agents will be deemed to be underwriting commissions or discounts. We have also agreed to provide indemnification and contribution to Cowenthe Sales Agents with respect to certain liabilities, including liabilities under the Securities Act or the Securities Exchange Act of 1934, as amended, or the Exchange Act.

Investing in our common stocksecurities involves a high degree of risk. Please readYou should review carefully the information contained inrisks and incorporated by referenceuncertainties referenced under the heading “Risk Factors”“Risk Factors” on page 46 of this prospectus as well as those contained in any accompanying prospectus and under similar headingsany related free writing prospectus or prospectus supplement we prepare or authorize in connection with this offering, and in the other documents that are filed after the date hereof and incorporated by reference into this prospectus or the accompanying prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Cowen and Company

The date of this prospectus is                      , 2016.2021.

TABLE OF CONTENTS

WHERE YOU CAN FIND MORE INFORMATION; INCORPORATION BY REFERENCE

Available Information

We file reports, proxy statements and other information with the SEC. The SEC maintains a web site that contains reports, proxy and information statements and other information about issuers, such as us, who file electronically with the SEC. The address of that website is www.sec.gov.

Our web site address is www. chinooktx.com. The information on our web site, however, is not, and should not be deemed to be, a part of this prospectus.

This prospectus is part of a registration statement that we filed with the SEC and does not contain all of the information in the registration statement. The full registration statement may be obtained from the SEC or us, as provided below. Documents establishing the terms of the offered securities are or may be filed as exhibits to the registration statement. Statements in this prospectus about these documents are summaries and each statement is qualified in all respects by reference to the document to which it refers. You should refer to the actual documents for a more complete description of the relevant matters. You may inspect a copy of the registration statement through the SEC’s website, as provided above, or at our principal executive offices, 1600 Fairview Avenue East, Suite 100 Seattle, WA 98102, during normal business hours.

Incorporation by Reference

The SEC allows us to “incorporate by reference” information that we file with the SEC, which means that we can disclose important information to you by referring you to those other documents. The information incorporated by reference is an important part of this prospectus, and information we file later with the SEC will automatically update and supersede this information. A Current Report (or portion thereof) furnished, but not filed, on Form 8-K shall not be incorporated by reference into this prospectus. We incorporate by reference the documents listed below and any future filings we make with the SEC under Section 13(a), 13(c), 14, or 15(d) of the Exchange Act prior to the termination of any offering of securities made by this prospectus:

i

All reports; and other documents we subsequently file pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act prior to the termination of this offering, including all such documents we may file with the SEC after the date of the initial registration statement and prior to the effectiveness of the registration statement, but excluding any information furnished to, rather than filed with, the SEC, will also be incorporated by reference in this prospectus and deemed to be part of this prospectus from the date of the filing of such reports and documents.

Any statement contained in this prospectus, or in a document, all or a portion of which is incorporated by reference, shall be modified or superseded for purposes of this prospectus to the extent that a statement contained in this prospectus, any prospectus supplement or any document incorporated by reference modifies or supersedes such statement. Any such statement so modified or superseded shall not, except as so modified or superseded, constitute a part of this prospectus.

RISK FACTORS

InvestingInvestment in our common stockany securities offered pursuant to this prospectus and the accompanying base prospectus involves a high degree of risk. Before deciding whether to invest in our common stock, yourisks. You should carefully consider carefully the risks and uncertaintiesrisk factors described below and under the heading “Risk Factors” contained in our QuarterlyAnnual Report on Form 10-Q10-K for the periodfiscal year ended MarchDecember 31, 2016, which are2020, incorporated by reference intoin this prospectus, any amendment or update thereto reflected in their entirety, as updatedsubsequent filings with the SEC, including in our Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q, and all other information contained or superseded by the risks and uncertainties described under similar headings in the other documents that are filed after the date hereof and incorporated by reference into this prospectus, together with the other information in this prospectus, as updated by our subsequent filings under the documents incorporated by reference and any free writing prospectus that we may authorize for use in connection with this offering.Exchange Act. The risks described in these documents are not the only ones we face, but those that we consider to be material. There may be other unknown or unpredictable economic, business, competitive, regulatory or other factors that could have material adverse effects on our future results. Past financial performance may not be a reliable indicatoroccurrence of future performance, and historical trends should not be used to anticipate results or trends in future periods. If any of these risks actually occurs, our business, financial condition, results of operations or cash flow could be seriously harmed. This couldmight cause the trading price of our common stockyou to decline, resulting in a loss oflose all or part of your investment. Please also read carefullyinvestment in the section below titled “Forward-Looking Statements.”offered securities.

Additional Risks RelatedRelating to Thisthis Offering

Management will have broad discretion as to the useIf you purchase shares of the proceeds fromour common stock sold in this offering, and may not use the proceeds effectively.

Because we have not designated the amount of net proceeds from this offering to be used for any particular purpose, our management will have broad discretion as to the application of the net proceeds from this offering and could use them for purposes other than those contemplated at the time of the offering. Our management may use the net proceeds for corporate purposes that may not improve our financial condition or market value.

Youyou may experience immediate and substantial dilution.dilution in the net tangible book value of your shares. In addition, we may issue additional equity or convertible debt securities in the future, which may result in additional dilution to you.

The offering price per share in this offeringof our common stock being offered may exceedbe higher than the net tangible book value per share of our outstanding common stock outstanding prior to this offering. Assuming that an aggregate of 7,320,6445,057,316 shares of our common stock are sold at a price of $13.66$14.83 per share, the last reported sale price of our common stock on the NASDAQNasdaq Global Select Market on April 27, 2016,6, 2021, for aggregate gross proceeds of $100approximately $75 million, and after deducting commissions and estimated offering expenses payable by us, younew investors in this offering will experienceincur immediate dilution of $9.52$8.12 per share, representingshare. For a more detailed discussion of the difference betweenforegoing, see the section entitled “Dilution” below. To the extent outstanding stock options or warrants are exercised, there will be further dilution to new investors. In addition, to the extent we need to raise additional capital in the future and we issue additional shares of common stock or securities convertible or exchangeable for our as adjustedcommon stock, our then existing stockholders may experience dilution and the new securities may have rights senior to those of our common stock offered in this offering.

We have broad discretion in the use of the net tangible book value per share as of March 31, 2016 after giving effect toproceeds from this offering and may not use them effectively.

Our management will have broad discretion in the assumedapplication of the net proceeds from this offering, price. The exerciseincluding for any of outstanding stock optionsthe purposes described in the section entitled “Use of Proceeds,” and warrantsyou will resultnot have the opportunity as part of your investment decision to assess whether the net proceeds are being used appropriately. Because of the number and variability of factors that will determine our use of the net proceeds from this offering, their ultimate use may vary substantially from their currently intended use. Our management might not apply our net proceeds in further dilutionways that ultimately increase the value of your investment. SeeWe expect to use the section titled “Dilution” below fornet proceeds from this offering to fund research, development of our product candidates, working capital, capital expenditures and other general corporate purposes. The failure by our management to apply these funds effectively could harm our business. Pending their use, we plan to invest the net proceeds from this offering in short-term or long-term, investment-grade, interest-bearing securities. These investments may not yield a more detailed illustrationfavorable return to our stockholders. If we do not invest or apply the net proceeds from this offering in ways that enhance stockholder value, we may fail to achieve expected financial results, which could cause our stock price to decline.

The actual number of shares we will issue under the sales agreement, at any one time or in total, is uncertain.

Subject to certain limitations in the sales agreement and compliance with applicable law, we have the discretion to deliver a placement notice to the Sales Agents at any time throughout the term of the dilution you would incur if you participatesales agreement. The number of shares that are sold by The Sales Agents after delivering a placement notice will fluctuate based on the market price of the common shares during the sales period and limits we set with the Sales Agents. Because the price per share of each share sold will fluctuate based on the market price of our common stock during the sales period, it is not possible at this stage to predict the number of shares that will be ultimately issued.

The common stock offered hereby will be sold in “at the market offerings”, and investors who buy shares at different times will likely pay different prices.

Investors who purchase shares in this offering.

We are subject to market price volatility.

The stock markets in general, and the markets for pharmaceutical, biopharmaceutical and biotechnology stocks in particular, have experienced extreme volatility, including as a result of the COVID-19 pandemic, that has often been unrelated to the operating performance of the issuer. Furthermore, the trading price of our common stock may be adversely affected by third-parties trying to drive down the market price. Short sellers and others, some of whom post anonymously on social media, may be positioned to profit if our stock declines and their activities can negatively affect our stock price. These broad market and industry factors may seriously harm the market price of our common stock, regardless of our operating performance.

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus including theand documents that we incorporateincorporated herein by reference herein, contains, and any applicable prospectus supplement or free writing prospectus includingcontain “forward-looking statements” within the documents we incorporate by reference therein may contain,meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements includinginvolve a number of risks and uncertainties. We caution readers that any forward-looking statement is not a guarantee of future performance and that actual results could differ materially from those contained in the forward-looking statement. These statements regarding ourare based on current expectations of future financial condition, business strategy and plans and objectives of management for future operations. Forward-lookingevents.

Such statements include, allbut are not limited to, statements concerning the following:

In some cases you can identify these statements by forward-looking words such as “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “intend,” “could,” “would,” “project,” “plan,” “expect” or the negative or plural of these words or similar expressions. expressions, in documents incorporated by reference into this prospectus or any free writing prospectus. We intend that such forward-looking statements be subject to the safe harbors created thereby.

These forward-looking statements include, but are not limited to, statements concerning the following:

These statements reflect our current views with respect to future events and are based on assumptionsthe current beliefs and expectations of our management and are subject to significant risks and uncertainties. Given theseIf underlying assumptions prove inaccurate or unknown risks or uncertainties you shouldmaterialize, actual results may differ materially from current expectations and projections. Factors that might cause such a difference include those discussed in Part II, Item 1A, “Risk Factors,” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2020, as well as those discussed in this prospectus, the documents incorporated by reference into this prospectus and any free writing prospectus. You are cautioned not to place undue reliance on these forward-looking statements. We discuss in greater detail, and incorporate by reference into this prospectus in their entirety, many of these risks under the headings “Risk Factors” on page 4 of this prospectus and in our Quarterly Report on Form 10-Q for the period ended March 31, 2016,statements, which is incorporated herein by reference, as may be updated or superseded by the risks and uncertainties described under similar headings in the other documents that are filed after the date hereof and incorporated by reference into this prospectus. Also, these forward-looking statements represent our estimates and assumptionsspeak only as of the date of this prospectus supplement. Unless requiredor, in the case of documents referred to or incorporated by law, wereference, the date of those documents.

All subsequent written or oral forward-looking statements attributable to us or any person acting on our behalf are expressly qualified in their entirety by the cautionary statements contained or referred to in this section. We do not undertake noany obligation to update or reviserelease publicly any revisions to these forward-looking statements to reflect new information or future events or developments. Thus, you should not assume that our silence over time means that actual events are bearing out as expressed or implied in such forward-looking statements. You should readcircumstances after the date of this prospectus or to reflect the documentsoccurrence of unanticipated events, except as may be required under applicable U.S. securities law. If we have filed with the SEC that are incorporated by reference and any free writing prospectusdo update one or more forward-looking statements, no inference should be drawn that we may authorize for use in connectionwill make additional updates with this offering completely and with the understanding that our actual future results may be materially different from what we expect. We qualify all of therespect to those or other forward-looking statements in the foregoing documents by these cautionary statements.

USE OF PROCEEDS

We may issue and sell shares of our common stock having aggregate sales proceeds of up to $100$75.0 million from time to time. Because there is no minimum offering amount required as a condition to close this offering, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time. There can be no assurance that we will sell any shares under or fully utilize the Sales Agreement as a source of financing.

We currently intend to use any net proceeds from the sale of securities under this prospectus primarily to fund research, development of our product candidates, working capital, capital expenditures and other general corporate purposes. Additionally, we may use a portion of the net proceeds from this offering primarily for research, development and manufacturing ofto expand our current business by in-licensing or acquiring, as the case may be, commercial products, product candidates, technologies, compounds, other assets or complementary businesses, using cash or shares of our common stock. However, we have no current commitments or obligations to do so.

The amounts and timing of our actual expenditures will depend on numerous factors, including the progress of our clinical trials and other development efforts and other factors described under “Risk Factors” in this prospectus, the accompanying base prospectus and the documents incorporated by reference herein and therein, as well as the amount of cash used in our operations. We may find it necessary or advisable to use the net proceeds for other general corporate purposes.purposes, and we will have broad discretion in the application of the net proceeds. Pending thesethe uses described above, we expectplan to invest the net proceeds from this offering in short-term or long-term, investment-grade, interest-bearing securities.

DIVIDEND POLICY

We have never declared or paid any cash dividends on our capital stock. We intend to retain future earnings, if any, to finance the operation and expansion of our business and do not anticipate paying any cash dividends in the foreseeable future. Any future determination related to our dividend policy will be made at the discretion of our board of directors after considering our financial condition, results of operations, capital requirements, business prospects and other factors the board of directors deems relevant, and subject to the restrictions contained in any future financing instruments.

DILUTION

Our net tangible book value as of March 31, 2016 was approximately $201.0 million, or $3.11 per share. Net tangible book value per share is determined by dividing our total tangible assets, less total liabilities, by the number of shares ofIf you invest in our common stock, outstanding asyour interest will be diluted to the extent of March 31, 2016. Dilution with respect to net tangible book value per share represents the difference between the amountprice per share paid by purchasers of shares of common stockyou pay in this offering and the net tangible book value per share of our common stock immediately after this offering.

Our net tangible book value of our common stock as of December 31, 2020 was approximately $245,190,000, or approximately $5.80 per share of common stock based upon 42,282,381 shares outstanding. Net tangible book value per share is equal to our total tangible assets, less our total liabilities, divided by the total number of shares outstanding as of December 31, 2020.

After giving effect to the assumed sale of 7,320,644 shares of our common stock in this offeringthe aggregate amount of $75.0 million at an assumed offering price of $13.66$14.83 per share, the last reported sale price of our common stock on the NASDAQNasdaq Global Select Market on April 27, 2016,6, 2021, and after deducting estimated offering commissions and estimated offering expenses payable by us, our as adjusted net tangible book value as of MarchDecember 31, 20162020 would have been approximately $297.9 million,$317,730,000, or $4.14$6.71 per share.share of common stock. This represents an immediate increase in net tangible book value of $1.03$0.91 per share to our existing stockholders and an immediate dilution in net tangible book value of $9.52$8.12 per share to new investors purchasing our common stock in this offering at the public offering price. offering.

The following table illustrates this dilutioncalculation on a per share basis:

basis. The table above assumes foras-adjusted information is illustrative purposes that an aggregateonly and will adjust based on the actual price to the public, the actual number of 7,320,644shares sold and other terms of the offering determined at the time shares of our common stock are sold duringpursuant to this prospectus. The as-adjusted information assumes that all of our common stock in the termaggregate amount of $75.0 million is sold at the sales agreement with Cowen at aassumed offering price of $13.66$14.83 per share, the last reported sale price of our common stock on The NASDAQthe Nasdaq Global Select Market on April 27, 2016, for aggregate gross proceeds of $100 million.6, 2021. The shares subject to the sales agreement with Cowen are beingsold in this offering, if any, will be sold from time to time at various prices. An increase

The number of $0.50 per share in the price at which the shares are sold from the assumed offering price of $13.66 per share shown in the table above, assuming all of our common stock in the aggregate amount of $100 million during the term of the sales agreement with Cowen is sold at that price, would increase our adjusted net tangible book value per shareto be outstanding after the offering to $4.16 per share and would increase the dilution in net tangible book value per share to new investors in this offering to $9.50 per share, after deducting commissions and estimated aggregate offering expenses payable by us. A decrease of $0.50 per share in the price at which theis based on 42,282,381 shares are sold from the assumed offering price of $13.66 per share shown in the table above, assuming all of our common stock in the aggregate amount of $100 million during the term of the sales agreement with Cowen is sold at that price, would decrease our adjusted net tangible book value per share after the offering to $4.13 per share and would decrease the dilution in net tangible book value per share to new investors in this offering to $9.53 per share, after deducting commissions and estimated offering expenses payable by us. This information is supplied for illustrative purposes only and may differ based on the actual offering price and the actual number of shares offered.

The above discussion and table are based on 64,559,772 shares outstanding as of MarchDecember 31, 2016,2020, and excludeexcludes:

•

7,237,724 shares of common stock reserved for future issuance under our 2015 Equity Incentive Plan; and

To the extent that options or warrants outstanding as of MarchDecember 31, 2016 have been or may be exercised or other2020, with a weighted-average exercise price of $0.52 per share; and

DESCRIPTION OF CAPITAL STOCK

AsGeneral

The following is a summary description of the datematerial terms of this prospectus, our capital stock. The description of capital stock is intended as a summary and is qualified in its entirety by reference to our restated certificate of incorporation, as amended (“certificate of incorporation”), and our amended and restated bylaws, as amended (“bylaws”), copies of which are filed as exhibits to our most recent Annual Report on Form 10-K and are incorporated by reference herein. We encourage you to read our certificate of incorporation, our bylaws and the applicable provisions of the Delaware General Corporation Law, or DGCL, for additional information.

Our certificate of incorporation authorizes us to issue up to 300,000,000 shares of common stock, $0.0001 par value per share, and 10,000,000 shares of preferred stock, $0.0001 par value per share.

As of MarchDecember 31, 2016, 64,559,7722020, there were 42,282,381 shares of our common stock were outstanding, and no shares of preferred stock were outstanding.

The following summary describes the material terms of our capital stock. The description of capital stock is qualified by reference to our certificate of incorporation and our bylaws.

Common Stock

Voting Rights

Each holder of our common stock is entitled to one vote for each share on all matters submitted to a vote of the stockholders, including the election of directors. Under our certificate of incorporation and bylaws, our stockholders do not have cumulative voting rights. Because of this, the holders of a majority of the shares of common stock entitled to vote in any election of directors can elect all of the directors standing for election, if they should so choose.

Dividends

Subject to preferences that may be applicable to any then-outstanding preferred stock, holders of common stock are entitled to receive ratably those dividends, if any, as may be declared from time to time by the board of directors out of legally available funds.

Liquidation

In the event of our liquidation, dissolution or winding up, holders of common stock will be entitled to share ratably in the net assets legally available for distribution to stockholders after the payment of all of our debts and other liabilities and the satisfaction of any liquidation preference granted to the holders of any then-outstanding shares of preferred stock.

Rights and Preferences

Holders of common stock have no preemptive, conversion or subscription rights and there are no redemption or sinking fund provisions applicable to the common stock. The rights, preferences and privileges of the holders of common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of preferred stock that we may designate and issue in the future.

Preferred Stock

Under our certificate of incorporation, our board of directors is authorized by resolution to divide the preferred stock into series and, with respect to each series, to determine the designations and the powers, preferences and rights, and the qualifications, limitations and restrictions thereof, including the dividend rights, conversion or exchange rights, voting rights, redemption rights and terms, liquidation preferences, sinking fund provisions and the number of shares constituting the series. Our board of directors can, without stockholder approval but subject to the terms of the certificate of incorporation, issue preferred stock with voting and other rights that could adversely affect the voting power of the holders of our common stock and which could have certain anti-takeover effects. Before we may issue any series of preferred stock, our board of directors will be required to adopt resolutions creating and designating such series of preferred stock.

The following summary of terms of our preferred stock is not complete. You should refer to the provisions of our certificate of incorporation and bylaws and the resolutions containing the terms of each class or series of the preferred stock which have been or will be filed with the SEC at or prior to the time of issuance of such class or series of preferred stock and described in the applicable prospectus supplement. The applicable prospectus supplement may also state that any of the terms set forth herein are inapplicable to such series of preferred stock, provided that the information set forth in such prospectus supplement does not constitute material changes to the information herein such that it alters the nature of the offering or the securities offered.

We will fix the designations, voting powers, preferences and rights of the preferred stock of each series we issue under this prospectus, as well as the qualifications, limitations or restrictions thereof, in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering. We will describe in the applicable prospectus supplement the terms of the series of preferred stock being offered, including, to the extent applicable:

If we issue shares of preferred stock under this prospectus, the shares will be fully paid and non-assessable.

The issuance of preferred stock could adversely affect the voting power of holders of common stock and reduce the likelihood that common stockholders will receive dividend payments and payments upon liquidation. The issuance could have the effect of decreasing the market price of the common stock. The issuance of preferred stock also could have the effect of delaying, deterring or preventing a change in control of us.

Registration Rights

We are party to an amended and restated investors’ rights agreement that provides that holders of our common stock, including certain holders of 5% of our capital stock and entities affiliated with certain of our directors, have certain registration rights, as set forth below. The registration of shares of our common stock pursuant to the exercise of registration rights described below would enable the holders to sell these shares without restriction under the Securities Act when the applicable registration statement is declared effective. We will pay the registration expenses, other than the underwriting discount, of the shares registered pursuant to the demand, piggyback and Form S-3 registrations described below.

Generally, in an underwritten offering, the managing underwriter, if any, has the right, subject to specified conditions, to limit the number of shares such holders may include. The demand, piggyback and Form S-3 registration rights described below will expire upon the earlier April 20, 2020, which is five years following the completion of our initial public offering, or when all investors, considered with their affiliates, can sell all of their shares in a 90-day period under Rule 144.

Demand Registration Rights

Upon the written request of certain of the holders of the registrable securities then outstanding that we file a registration statement under the Securities Act covering the registration of registrable securities having an aggregate offering price to the public of not less than $5.0 million, we will be required to use our best efforts to register all or a portion of their registrable securities that holders may request to be registered. We are not required to effect such registrations on more than two occasions.

Piggyback Registration Rights

In the event that we propose to register any of our securities under the Securities Act in a future offering, either for our own account or for the account of other security holders, the holders of registrable securities will be entitled to certain “piggyback” registration rights allowing them to include their shares in such registration, subject to certain marketing and other limitations. As a result, whenever we propose to file a registration statement under the Securities Act, including a registration statement on Form S-3 as discussed below, other than with respect to a demand registration or a registration statement on Forms S-4 or S-8 or related to stock issued upon conversion of debt securities, the holders of these shares are entitled to notice of the registration and have the right, subject to limitations that the underwriters may impose on the number of shares included in the registration, to include their shares in the registration.

In connection with the filing of the registration statement of which this prospectus forms a part, certain holders of shares of common stock were entitled to, and the necessary percentage of holders waived, their rights to notice of such filing and to include their shares of registrable securities in the registration statement of which this prospectus forms a part.

Form S-3 Registration Rights

The holders of registrable securities are entitled to certain Form S-3 registration rights. Such request for registration on Form S-3 must cover securities the aggregate offering price of which, before payment of the underwriting discount, equals or exceeds $1.5 million.

Anti-Takeover Provisions

Certificate of Incorporation and Bylaws

Because our stockholders do not have cumulative voting rights, our stockholders holding a majority of the outstanding shares of common stock outstanding will be able to elect all of our directors. Our certificate of incorporation and bylaws provide that all stockholder actions must be effected at a duly called meeting of stockholders and not by written consent. A special meeting of stockholders may be called by the chairman of our board of directors, the majority of our whole board of directors, or our chief executive officer.

Our certificate of incorporation provides for our board of directors to be divided into three classes, with staggered three-year terms. As a result, only one class of directors will beis elected at each annual meeting of stockholders, with the other classes continuing for the remainder of their respective three-year terms. Stockholders have no cumulative voting rights, and the stockholders representing a majority of the shares of common stock entitled to vote in any election of directors may elect all of the directors standing for election. In addition, our certificate of incorporation provides that stockholders may remove directors only for cause and only by the affirmative vote of the holders of at least sixty-six and two-thirds percent (66-2/3%) in voting power of our stock entitled to vote thereon.

Our certificate of incorporation further provides that the affirmative vote of holders of at least sixty-six and two-thirds percent (66-2/3%) of the voting power of all of the then outstanding shares of voting stock, voting as a single class, will be required to amend certain provisions of our certificate of incorporation, including provisions relating to the size of the board, removal of directors, special meetings, actions by written consent and cumulative voting. The affirmative vote of holders of at least sixty-six and two-thirds percent (66-2/3%) of the voting power of all of the then outstanding shares of voting stock, voting as a single class, will beis required to amend or repeal our bylaws, although our bylaws may be amended by a simple majority vote of our board of directors.

The foregoing provisions make it more difficult for our existing stockholders to replace our board of directors as well as for another party to obtain control of us by replacing our board of directors. Since our board of directors has the power to retain and discharge our officers, these provisions could also make it more difficult for existing stockholders or another party to effect a change in management. In addition, the authorization of undesignated preferred stock makes it possible for our board of directors to issue preferred stock with voting or other rights or preferences that could impede the success of any attempt to cause a change in control of us.

These provisions are intended to enhance the likelihood of continued stability in the composition of our board of directors and its policies and to discourage certain types of transactions that may involve an actual or threatened acquisition of us. These provisions are also designed to reduce our vulnerability to an unsolicited acquisition proposal and to discourage certain tactics that may be used in proxy fights. However, such provisions could have the effect of discouraging a change of control of our company or changes in our board of directors that our stockholders might consider favorable. As a consequence, these provisions also may inhibit fluctuations in the market price of our stock that could result from actual or rumored takeover attempts.

Section 203 of the Delaware General Corporation Law

We are subject to Section 203 of the Delaware General Corporation Law,DGCL, which prohibits a Delaware corporation from engaging in anya business combination with any interested stockholder for a period of three years afterfollowing the date that such stockholderthe person became an interested stockholder, (as defined below), with the following exceptions:

(but not the outstanding voting stock owned by the interested stockholder) those shares owned by (i) persons who are directors and also officers and (ii) employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or

In general, Section 203 of the DGCL defines business combination to include the following:

In general, Section 203 of the DGCL defines an “interested stockholder” as an entity or person who, together with the entity’s or person’s affiliates and associates, beneficially owns, or is an affiliate of the corporation and within three years prior to the time of determination of interested stockholder status did own, 15% or more of the outstanding voting stock of the corporation.

A Delaware corporation may “opt out” of these provisions with an express provision in its certificate of incorporation. We have not opted out of these provisions, which may as a result, discourage or prevent mergers or other takeover or change of control attempts of our company.us.

Choice of Forum

Our certificate of incorporation provides that the Court of Chancery of the State of Delaware will be the exclusive forum for any derivative action or proceeding brought on our behalf; any action asserting a breach of fiduciary duty; any action asserting a claim against us arising pursuant to the Delaware General Corporation Law,DGCL, our certificate of incorporation or our bylaws; or any action asserting a claim against us that is governed by the internal affairs doctrine.

Listing

Our common stock The enforceability of similar choice of forum provisions in other companies’ certificates of incorporation has been challenged in legal proceedings and it is listedpossible that a court could find these types of provisions to be inapplicable or unenforceable. Similarly, our bylaws provide that (a) the Court of Chancery of the State of Delaware will be the sole and exclusive forum for any derivative action or proceeding brought on our behalf; any action asserting a breach of fiduciary duty; any action asserting a claim against us arising pursuant to the NASDAQ Global Select MarketDGCL; or any action asserting a claim against us that is governed by the internal affairs doctrine, and (b) the federal district courts of the United Stated of America are the exclusive forum for the resolution of any complaint asserting a cause of action arising under the symbol “ADRO.”Securities Act of 1933, as amended. Although our bylaws contain the choice of forum provision described above, it is possible that a court could find that such provisions are inapplicable for a particular claim or action or that such provisions are unenforceable.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Computershare Trust Company, N.A. The transfer agent and registrar’s address is 250 Royall Street, Canton, Massachusetts 02021.

Exchange Listing

Our common stock is listed on the Nasdaq Global Select Market under the symbol “KDNY.”

PLAN OF DISTRIBUTION

We have entered into a sales agreementSales Agreement with Cowen,SVB Leerink and Cantor on April 7, 2021, under which we may issue and sell from time to time up to $100,000,000$75,000,000 of our common stock through Cowenor to the sales agents, as our sales agent.agent or principal. Sales of our common stock, if any, under the Sales Agreement will be made at market prices by any method that is deemed to be an “at the market offering” as defined in Rule 415415(a)(4) under the Securities Act, including sales made directly on The NASDAQ Global Select Market or any other trading market for ourAct.

Each time we wish to issue and sell common stock orunder the Sales Agreement, we will notify one designated sales agent of the number of shares to or through a market maker other thanbe issued, the dates on an exchange. If authorized by us in writing, Cowenwhich such sales are anticipated to be made and any minimum price below which sales may also sell our shares of common stock by any other method permitted by law, including negotiated transactions, and Cowen may also purchase shares of our common stock as principal.

Cowen will offer our common stock subjectnot be made. Once we have so instructed such designated sales agent, unless such sales agent decline to accept the terms and conditions of thethis notice, such sales agreement on a daily basis or as otherwiseagent has agreed upon by us and Cowen. We will designate the maximum amount of common stock to be sold through Cowen on a daily basis or otherwise determine such maximum amount together with Cowen. Subject to the terms and conditions of the sales agreement, Cowen will use its commercially reasonable efforts consistent with its normal trading and sales practices to sell such shares up to the amount specified on our behalf allsuch terms. The obligations of the shares of common stock requestedsales agents under the Sales Agreement to be sold by us. We may instruct Cowen not to sell common stock if the sales cannot be effected at or above the price designated by us in any such instruction. Cowen or we may suspend the offering of our common stock being made through Cowen under the sales agreement upon proper noticeare subject to the other party. Cowen anda number of conditions that we each have the right, by giving written notice as specified in the sales agreement, to terminate the sales agreement in each party’s sole discretion at any time.must meet.

The aggregate compensation payable to Cowen assettlement between us and each sales agent equals upis generally anticipated to 3.0% of the gross sales price of the shares sold through it pursuant to the sales agreement. We have also agreed to reimburse Cowen up to $40,000 of Cowen’s actual outside legal expenses incurred by Cowen in connection with this offering, and for certain other expenses, including Cowen’s FINRA counsel fees in an amount up to $10,000. We estimate that the total expenses of the offering payable by us, excluding commissions payable to Cowen under the sales agreement, will be approximately $125,000.

The remaining sales proceeds, after deducting any expenses payable by us and any transaction fees imposed by any governmental, regulatory, or self-regulatory organization in connection with the sales, will equal our net proceeds for the sale of such common stock.

Cowen will provide written confirmation to us following the close of trading on The NASDAQ Global Select Market on each day in which common stock is sold through it as sales agent under the sales agreement. Each confirmation will include the number of shares of common stock sold through it as sales agent on that day, the volume weighted average price of the shares sold, the percentage of the daily trading volume and the net proceeds to us.

We will report at least quarterly the number of shares of common stock sold through Cowen under the sales agreement, the net proceeds to us and the compensation paid by us to Cowen in connection with the sales of common stock.

Settlement for sales of common stock will occur unless the parties agree otherwise, on the third business day that is also asecond trading day following the date on which anythe sale was made. Sales of our common stock as contemplated in this prospectus supplement will be settled through the facilities of Computershare Trust Company, N.A. or by such other means as we and each sales were made in return for payment of the net proceeds to us.agent may agree upon. There is no arrangement for funds to be received in an escrow, trust or similar arrangement.

We will pay the sales agents commissions for their services in acting as agents in the sale of our common stock. Each sales agent will be entitled to compensation at a fixed commission rate equal to up to 3.0% of the gross sales price per share sold by such sales agent under the Sales Agreement. We have also agreed to reimburse the agents for certain expenses incurred in connection with the offering of our common stock pursuant to the Sales Agreement, up to a maximum of $75,000. Additionally, pursuant to the terms of the Sales Agreement, we agreed to reimburse the agents for the documented fees and costs of its legal counsel reasonably incurred in connection with the sales agents’ ongoing diligence arising from the transactions contemplated by the Sales Agreement in an amount not to exceed $15,000 in the aggregate per calendar quarter. Because there is no minimum offering amount required as a condition to close this offering, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time. In connection with the salessale of ourthe common stock on our behalf, Cowen mayeach sales agent will be deemed to be an “underwriter” within the meaning of the Securities Act and the compensation paid to Cowen mayof such sales agent will be deemed to be underwriting commissions or discounts. We have agreed in the sales agreement to provide indemnification and contribution to Cowen againsteach sales agent with respect to certain civil liabilities, including liabilities under the Securities Act. AsWe estimate that the total expenses for the offering, excluding compensation payable to the sales agent, Cowenagents under the terms of the Sales Agreement, will not engage in any transactions that stabilizes our common stock.

OurThe offering of common stock is listed on The NASDAQ Global Select Market and trades underpursuant to this prospectus supplement will terminate upon the symbol “ADRO.” The transfer agentearlier of (i) the sale of our common stock provided for in this prospectus supplement, or (ii) termination of the Sales Agreement as permitted therein.

Each sales agent may terminate such sales agent’s obligations under the Sales Agreement at any time in certain circumstances, including the occurrence of a material adverse change with respect to us that, in such sales agent’s sole judgment, makes it impracticable or inadvisable to market the shares, if there has occurred any material adverse change in the U.S. financial markets or international financial markets, which in such sales agent’s sole judgment makes it impracticable to market the shares, if trading in the shares has been suspended or limited by the SEC or The Nasdaq Global Select Market, or the Exchange, or if trading generally has been suspended or limited by the Exchange, if any suspension of trading of our common stock on any exchange or over-the counter market shall have occurred and be continuing, if there is Computershare Trust Company, N.A. a major disruption of securities settlements or clearance services in the U.S. which shall be continuing, or if a banking moratorium has been declared in the U.S. Federal

or New York authorities. Either sales agent may terminate the Sales Agreement, with respect to such sales agent’s rights and obligations under the Sales Agreement, at any time upon five days’ prior notice. We may terminate the Sales Agreement with respect to either or both sales agents at any time upon five days’ prior notice.

This summary of the material provisions of the Sales Agreement does not purport to be a complete statement of its terms and conditions. A copy of the Sales Agreement is filed with the SEC and are incorporated by reference into the registration statement of which this prospectus supplement is a part. See “Where You Can Find More Information” below.

The transfer agent’s address is 250 Royall Street, Canton, Massachusetts 02021.

Cowen and/or itssales agents and their respective affiliates have provided, and may in the future provide various investment banking, commercial banking and other financial services for us and our affiliates, for which services they have received and, may in the future receive customary fees.

This prospectus supplement in electronic format may be made available on a website maintained by each of the sales agents and the sales agents may distribute this prospectus supplement electronically.

LEGAL MATTERS

CooleyFenwick & West LLP, Palo Alto, California, has passedSeattle, Washington, will pass upon certain legal matters relating to the validityissuance and sale of the common stocksecurities offered by this prospectus. Ashereby on behalf of the date of this prospectus, attorneys with Cooley LLP participating in the preparation of this prospectus and the related Registration Statement on Form S-3 beneficially own an aggregate of 8,500 shares of our common stock. Duane Morris LLP, Newark, New Jersey, is counsel for CowenChinook Therapeutics, Inc. The Sales Agents are being represented in connection with this offering.offering by Duane Morris LLP, New York, New York.

EXPERTS

The consolidated financial statements incorporated in this prospectusProspectus by reference fromto the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 have been audited by Deloitte & Toucheso incorporated in reliance on the reportof PricewaterhouseCoopers LLP, an independent registered public accounting firm, as stated in their report, which is incorporated herein by reference. Such financial statements have been so incorporated in reliance upongiven on the reportauthority of suchsaid firm given upon their authority as experts in accountingauditing and auditing.accounting.

•

our current report on Form 8-K/A filed with the SEC on January 13, 2016; and

You can request a copy of these filings, at no cost, by writing or telephoning us at the following address or telephone number:

Aduro Biotech, Inc.

626 Bancroft Way, 3C

Berkeley, California 94710

Attn: Investor Relations

This prospectus is part of a registration statement we filed with the SEC. That registration statement and the exhibits filed along with the registration statement contain more information about us and the shares in this offering. Because information about documents referred to in this prospectus is not always complete, you should read the full documents which are filed as exhibits to the registration statement. You may read and copy the full registration statement and its exhibits at the SEC’s public reference rooms or its website.

$100,000,000

Up to $75,000,000

Common Stock

ProspectusPROSPECTUS SUPPLEMENT

SVB Leerink

Cantor

                , 2021

Cowen and Company

                    , 2016

PART II

INFORMATION NOT REQUIRED IN THE PROSPECTUS

Item 14. Other Expenses of Issuance and Distribution.Distribution

The following table sets forth an estimate of the fees andestimated expenses other than the underwriting discounts and commissions, payable by us in connection with the issuance and distribution of the securities being registered. All the amounts shown are estimates, except for the SEC registration fee and the FINRA filing fee.registered:

Item 15. Indemnification of DirectorsOfficers and Officers.Directors

Section 145 of the Delaware General Corporation Law authorizes a court to award, or a corporation’s board of directors to grant, indemnity to directors and officers inunder certain circumstances and subject to certain limitations. The terms of Section 145 of the Delaware General Corporation Law are sufficiently broad to permit such indemnification under certain circumstances for liabilities, including reimbursement forof expenses incurred, arising under the Securities Act of 1933, as amended. Our amended and restated certificate of incorporation provides for indemnification of our directors, officers, employees and other agents to the maximum extent permitted by the Delaware General Corporation Law, and our amended and restated bylaws provide for indemnification of our directors, officers, employees and other agents to the maximum extent permitted by the Delaware General Corporation Law.

We have entered into indemnification agreements with our directors and executive officers, whereby we have agreed to indemnify our directors and executive officers to the fullest extent permitted by law, including indemnification against expenses and liabilities incurred in legal proceedings to which the director or executive officer was, or is threatened to be made, a party by reason of the fact that such director or executive officer is or was our director, officer, employee or agent, provided that such director or executive officer acted in good faith and in a manner that the director or executive officer reasonably believed to be in, or not opposed to, the our best interest. At present, there is no pending litigation or proceeding involving any of our directors or executive officers regarding which indemnification is sought, nor are we aware of any threatened litigation that may result in claims for indemnification.

We maintain insurance policies that indemnify our directors and officers against various liabilities arising under the Securities Act of 1933, as amended, or the Securities Act,Act.

As permitted by the Delaware General Corporation Law, the Registrant’s restated certificate of incorporation contains provisions that eliminate the personal liability of its directors for monetary damages for any breach of fiduciary duties as a director, except liability for the following:

As permitted by the Delaware General Corporation Law, the Registrant’s restated bylaws provide that:

The Registrant has entered, and intends to continue to enter, into indemnification agreements with each of its directors and executive officers to provide these directors and executive officers additional contractual

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assurances regarding the scope of the indemnification set forth in the Registrant’s restated certificate of incorporation and restated bylaws and to provide additional procedural protections. At present, there is no pending litigation or proceeding involving a director or executive officer of the Registrant for which indemnification is sought. The indemnification provisions in the Registrant’s restated certificate of incorporation, restated bylaws and the Securities Exchange Act of 1934, as amended, that mightindemnification agreements entered into or to be incurred by any director or officer in his capacity as such.

The Sales Agreement by andentered into between the Registrant and Coweneach of its directors and Company, LLC, or Cowen, providesexecutive officers may be sufficiently broad to permit indemnification of the Registrant’s directors and executive officers for indemnification by Cowen of us, our directors, our officers who signed the registration statement and our controlling persons for some liabilities, including liabilities arising under the Securities Act. In addition, the underwriting agreement that we may enter into (Exhibit 1.1) may provide

The Registrant currently carries liability insurance for indemnification by any underwriters of us, ourits directors our officers who signed the registration statement and our controlling persons for some liabilities, including liabilities arising under the Securities Act.officers.

Item 16. Exhibits.Exhibits

The list of exhibits is set forth under “Exhibit Index” at the endlisted below are filed (except where otherwise indicated) as part of this registration statement and is incorporated herein by reference.