UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of
the Securities Exchange Act of 1934

Filed by the Registrant ☑

File by a Party other than the Registrant ☐

Check the appropriate box:

☐ Preliminary Proxy Statement

☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

☑ Definitive Proxy Statement

☐ Definitive Additional Materials

☐ Soliciting Material under §240.14a-12

Payment of Filing Fee (Check the appropriate box):

April 16, 2018

April 16, 2019

Dear Stockholder:

The Board of Directors of Sun BioPharma, Inc. joins us in extending an invitation to attend our 20182019 Annual Meeting of Stockholders (the “Annual Meeting”), to be held on May 22, 2018,21, 2019, at the offices of Faegre Baker Daniels LLP, 2200 Wells Fargo Center, 90 South Seventh Street, Minneapolis, Minnesota, commencing at 2:30 p.m. local time. On or about April 16, 2018,2019, a full set of proxy materials will be mailed to each stockholder.

It is important that your shares be represented at the Annual Meeting whether or not you plan to attend in person. Please vote electronically over the Internet or, if you request and receive a paper copy of the proxy card by mail, you may vote by Internet or telephone or by returning your signed proxy card in the envelope provided. If you do attend the Annual Meeting and desire to vote in person, you may do so by following the procedures described in the proxy statement even if you have previously sent a proxy.voted.

On behalf of the Board of Directors and management, it is ourmy pleasure to express our appreciation for your continued support.

We hope that you will be able to attend the Annual Meeting.

Very truly yours,

/s/ Michael T. Cullen

Michael T. Cullen, M.D., M.B.A.

Executive Chairman of the Board

President and Chief Executive Officer

SUN BIOPHARMA, INC.
712 Vista Boulevard #305
Waconia, Minnesota 55387

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS
TO BE HELD MAY 22, 2018

To the Stockholders of Sun BioPharma, Inc.:

Notice is hereby given that the 20182019 Annual Meeting of Stockholders of Sun BioPharma, Inc., a Delaware corporation, will be held on May 22, 2018,21, 2019, at the offices of Faegre Baker Daniels LLP, 2200 Wells Fargo Center, 90 South Seventh Street, Minneapolis, Minnesota, commencing at 2:30 p.m. local time, for the following purposes:

Act on any other matters that may properly come before the Annual Meeting, and any adjournment or postponement thereof.

Only stockholders of record at the close of business on March 29, 2018, the record date for the meeting set by the Board of Directors, are entitled to notice of the Annual Meeting and may vote at the Annual Meeting or any adjournment(s) or postponement(s) thereof.

By Order of the Board of Directors,

YOUR VOTE IS IMPORTANT

Whether or not you plan to attend the Annual Meeting, we urge you to vote as soon as possible. If you attend the meeting, you may vote your shares in person if you wish, whether or not you submit a proxy in advance of the meeting.

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE

STOCKHOLDER MEETING TO BE HELD ON MAY 22, 2018
21, 2019

Our Proxy Statement for the 20182019 Annual Meeting of Stockholders and our Annual Report on Form 10-K for the fiscal year ended December 31, 2017,2018, are available at https://www.rdgir.com/sun-biopharma-inc.

TABLE OF CONTENTSTable of Contents

SUN BIOPHARMA, INC.
712 Vista Boulevard #305
Waconia, Minnesota 55387

PROXY STATEMENT

The Board of Directors of Sun BioPharma, Inc. (our “Company”(“our Company”) is soliciting proxies for use at the Annual Meeting of Stockholders to be held on May 22, 2018,21, 2019, and at any adjournment or postponement of the meeting.meeting (the “Annual Meeting”).

The Annual Meeting will be held at the offices of Faegre Baker Daniels LLP, 2200 Wells Fargo Center, 90 South Seventh Street, Minneapolis, Minnesota. Registration for the Annual Meeting will begin at 2:00 p.m., local time. The Annual Meeting will commence at 2:30 p.m., local time. This solicitation is being made by mail; however, we also may use our officers, directors and employees (without providing them with additional compensation) to solicit proxies from stockholders in person or by telephone, facsimile or letter. Distribution of this proxy statement and the proxy card is scheduled to begin on or about April 16, 2018.2019.

QUESTIONS AND ANSWERS ABOUT THE ANNUAL MEETING AND VOTING

Proposal 2 – Ratification of the selection of Cherry Bekaert LLP as our independent registered public accounting firm for the fiscal year ending December 31, 20189 - Provided a quorum is present at the Annual Meeting, this proposal will be approved if it received the affirmative vote of a majority of the shares of stock represented at the meeting and entitled to vote on the proposal.

Proposal 3 – Advisory vote on the compensation of the Company’s executive officers – We will consider our stockholders to have approved, on an advisory basis, our executive compensation if the number of votes cast in favor of“for” the actionproposal exceeds the number of votes cast in opposition“against” the proposal.

Proposal 4 – Advisory vote on the frequency of future votes on executive compensation – The option that receives the highest number of votes will be deemed to be the proposal.recommendation of our stockholders.

A properly executed proxy marked “ABSTAIN”“ABSTAIN” with respect to a proposal will be counted for purposes of determining whether there is a quorum and will be considered present in person or by proxy and entitled to vote but will not be deemed to have been voted in favor of such proposal. Abstentions will have the effect of a vote against Proposal 2 but will have no effect on the voting for the electionoutcomes of directors or any of the proposals.Proposals 1, 3 and 4.

You are a “beneficial owner” of shares held in “street name,” rather than a “stockholder“stockholder of record,” if your shares are held in the name of a broker, bank, trust or other nominee as a custodian, and this proxy statement and the accompanying notice were forwarded to you by that organization. As a beneficial owner, you have the right to direct your broker, bank, trust or other nominee how to vote your shares. You may vote by proxy by completing the voting instruction form provided by your custodian. Since a beneficial owner is not the stockholder of record, you may not vote your shares in person at the Annual Meeting unless you obtain a “legal proxy” from the broker, bank, trustee, or nominee that holds your shares giving you the right to vote the shares at the meeting.

Attendance at the meeting will not by itself revoke a previously granted proxy. Unless you decide to vote your shares in person, you should revoke your prior proxy in the same way you initially submitted it – that is, by Internet, facsimile or mail.

Shares held in street name. If you hold shares through a broker, you will receive voting instructions from your broker. If you do not submit voting instructions to your broker and your broker does not have discretion to vote your shares on a particular matter, then your shares will not be counted in determining the outcome of the vote on that matter at the Annual Meeting. See “What is the effect of broker non-votes and abstentions?” as described above. Your broker will not have discretion to vote your shares for any matter to be voted upon at the Annual Meeting other than the ratification of the selection of our independent registered public accounting firm. Accordingly, it is important that you provide voting instructions to your broker for the matters to be voted upon at the Annual Meeting.

If any matters not described in the proxy statement are properly presented at the Annual Meeting, the proxy holders will use their own judgment to determine how to vote your shares. If the Annual Meeting is adjourned, the proxy holders can vote your shares on the new meeting date as well, unless you have revoked your proxy instructions, as described under “Can I revoke or change my vote?”

PROPOSAL 1:
ELECTION OF CLASS II IIIDIRECTORS

Our business is overseen by a Board of Directors divided into three classes as nearly equal in number as possible, and directors typically are elected to a designated class for a term of three years. The following table sets forth certain information regarding the current members of our Board of Directors:

The Board of Directors has fixed at twoone the number of directors to be elected to the Board at the 20182019 Annual Meeting of Stockholders. Based upon the recommendation of its Nominating and Governance Committee, the Board of Directors has nominated Michael T. Cullen, M.D., M.B.A. and D. Robert SchemelJeffery S. Mathieson to stand for election for a three-year terms.term. Proxies solicited by the Board will, unless otherwise directed, be voted to elect the nominees namednominee as set forth below. The following table sets forth certain information regarding the current members of our Board of Directors:

The Board of Directors has fixed at two the number of directors to be elected to the Board at the 2018 Annual Meeting of Stockholders. Based upon the recommendation of its Nominating and Governance Committee, the Board of Directors has nominated Michael T. Cullen, M.D., M.B.A. and D. Robert Schemel to stand for election for three-year terms. Proxies solicited by the Board will, unless otherwise directed, be voted to elect the nominees named below.

Nominees for Class II Directors – Terms Expiring in 2021

Each of the nomineesnominee named below areis a current directorsdirector of our Company and each nominee has indicated a willingness to serve as a director for the term to which he or she is elected, but in case anythe nominee is not a candidate at the meeting for any reason, the proxy holders named in our form of proxy may vote for a substitute nominee in their discretion or our Board of Directors may recommend that the number of directors to be elected be reduced. The following table sets forth certain information regarding eachthe director nominee:

Jeffrey S. Mathiesen has served as a director of our Company since September 2015. He has served as Chief Financial Officer of Teewinot Life Sciences, a privately held biopharmaceutical company focused on the biosynthetic production of pure pharmaceutical grade cannabinoids since March 2019. Previously he served as Chief Financial Officer of Gemphire Therapeutics Inc., a publicly traded biopharmaceutical company from September 2015 to September 2018. From August 2015 to September 2015 he was a consultant to Gemphire. He served as Chief Financial Officer of Sunshine Heart, Inc., a publicly traded medical device company, from March 2011 to January 2015. From December 2005 to April 2010, Mr. Mathiesen served as Vice President and Chief Financial Officer of Zareba Systems, Inc., a manufacturer and marketer of medical products, perimeter fencing and security systems that was purchased by Woodstream Corporation in April 2010. Mr. Mathiesen has held executive positions with publicly traded companies dating back to 1993, including vice president and chief financial officer positions. Mr. Mathiesen also serves as a director and audit committee chairman of NeuroOne Medical Technologies Corporation, a publicly traded medical device company and as a director and audit committee chairman of eNeura, Inc., a privately held medical technology company providing therapy for both acute treatment and prevention of migraine. Mr. Mathiesen holds a B.S. in Accounting from the University of South Dakota and is also a Certified Public Accountant. We believe that Mr. Mathiesen brings financial insight and leadership and a wealth of experience in capital markets to the Board of Directors, as well as knowledge of public company accounting and financial reporting requirements

Class I Directors – Terms Expiring in 2020

Suzanne Gagnon, M.D., has served as our Chief Medical Officer and as a director of our Company since September 2015. Dr. Gagnon had previously served as a director of Sun BioPharma Research, Inc. (“SBR”), a former affiliate of the Company, since June 2015 and as its Chief Medical Officer since January 2015. Previously, Dr. Gagnon served as the Lead Clinical Consultant to the Company. Dr. Gagnon has been the President of Gagnon Consulting LLC since July 2014, consulting on medical, safety and regulatory matters. From December 2001 through July 2014, Dr. Gagnon had acted as the Chief Medical Officer for three companies, ICON Clinical Research, Nupathe, Inc. and Idis, Inc.

Paul W. Schaffer has served as a director since September 2015. Mr. Schaffer had previously served as a director of SBR since January 2014. Mr. Schaffer graduated from Minnesota Pharmacy School in 1966. He owned and operated a compounding pharmacy, Bloomington Drug, for 42 years. Mr. Schaffer is an experienced biotech investor. We believe that Mr. Schaffer brings a wealth of experience in pharmaceutical development and manufacturing to the Board of Directors, as well as knowledge of regulations and issues facing pharmaceutical companies.

Class II Directors –Terms Expiring in 2021

Michael T. Cullen, M.D., M.B.A., has served as Executive Chairman of the board and as a director of our Company since the effective timeSeptember 2015. He resumed responsibilities as President and Chief Executive Officer of the Merger.Company in October 2018. Dr. Cullen brings 30 years of pharmaceutical experience to our Company, including expertise in working with development-stage companies in planning, designing and advancing drug candidates from preclinical through clinical development. Dr. Cullen co-founded SBR in November 2011 and had continuously served as Chairman its board of directors since that date. He previously served as its Chief Executive Officer and President of SBR from November 2011 to June 2015. Dr. Cullen assumed responsibility as the President and Chief Executive Officer of the Company on October 31, 2018. Dr. Cullen provided due diligence consulting to the pharmaceutical industry from 2009 to 2011, after one year in transition consulting to Eisai Co., Ltd. He developed several oncology drugs as Chief Medical Officer for MGI Pharma Inc. from 2000 to 2008, and previously at G.D. Searle, SunPharm Corporation, and as Vice President for Clinical Consulting at IBAH Inc., the world’s fifth largest contract research organization, where he provided consulting services on business strategy, creating development plans, regulatory matters and designing clinical trials for several development stage companies in the pharmaceutical industry. Dr. Cullen was also a co-founder and Chief Executive Officer of IDD Medical, a pharmaceutical start-up company. Dr. Cullen joined 3M Pharmaceuticals in 1988 and contributed to the development of cardiovascular, rheumatology, pulmonary and immune-response modification drugs. Over the course of his career Dr. Cullen has been instrumental in obtaining the approval of ten drugs, including three (3) since 2004: Aloxi®, Dacogen® and Lusedra®. Board-certified in Internal Medicine, Dr. Cullen practiced from 1977 to 1988 at Owatonna Clinic, Owatonna, MN, where he served as president. Dr. Cullen earned his MD and BS degrees from the University of Minnesota and his MBA from the University of St. Thomas and completed his residency and Board certification in Internal Medicine through the University of North Carolina in Chapel Hill and Wilmington, NC.

D. Robert Schemel has served as a director since the effective time of the Merger.September 2015. Mr. Schemel had previously served as a director of SBR since March 2012. Mr. Schemel has over 39 years’ experience in the agriculture industry. From 1973-2005, Mr. Schemel owned and operated a farming operation in Kandiyohi County, Minnesota, building a 5,000-acre operation producing corn, soybeans and sugar beets. Mr. Schemel has extensive experience in serving on boards of directors. From 1992-1996 he served as a board member for ValAdCo and then from 1996-2003 he served as the Chairman of the Board for Phenix Biocomposites. We believe that Mr. Schemel brings business insight and leadership as well as significant experience in the development and growth of early stage companies.

Class I Directors – Terms Expiring in 2020

Suzanne Gagnon, M.D., has served as our Chief Medical Officer and as a director of our Company since September 4, 2015. Dr. Gagnon had previously served as a director of Sun BioPharma Research, Inc. (“SBR”), a former affiliate of the Company, since June 2015 and as its Chief Medical Officer since January 2015. Previously, Dr. Gagnon served as the Lead Clinical Consultant to the Company. Prior to working for the Company, Dr. Gagnon was the President of Gagnon Consulting LLC from July 2014 through December 2014 consulting on medical, safety and regulatory matters. From December 2001 through July 2014, Dr. Gagnon had acted as the Chief Medical Officer for three companies, ICON Clinical Research, Nupathe, Inc. and Idis, Inc.

David B. Kaysen has served as our President and Chief Executive Officer and as a director of our Company since September 4, 2015. Mr. Kaysen had previously served as the President of SBR since August 2015 and as Chief Executive Officer and as a director of SBR since July 2015. Prior to joining the Company, Mr. Kaysen was a self-employed medical technology consultant since April 2013. Mr. Kaysen previously was the President, Chief Executive Officer and a board member of Uroplasty, Inc. (now Cogentix Medical, Inc.), a publicly traded medical device company, from May 2006 through April 2013. Prior to that, Mr. Kaysen served as President and CEO and as a director of Diametrics Medical, a publicly traded diagnostics company, and Rehabilicare Inc. (now Compex Technologies), a publicly traded neuromodulation medical device company. Mr. Kaysen holds a Bachelor of Science in Business Administration from the University of Minnesota.

Paul W. Schaffer has served as a director since September 4, 2015. Mr. Schaffer had previously served as a director of SBR since January 2014. Mr. Schaffer graduated from Minnesota Pharmacy School in 1966. He owned and operated a compounding pharmacy, Bloomington Drug, for 42 years. Mr. Schaffer is an experienced biotech investor. We believe that Mr. Schaffer brings a wealth of experience in pharmaceutical development and manufacturing to the Board of Directors, as well as knowledge of regulations and issues facing pharmaceutical companies.

Class III Directors –Terms Expiring in 2019

Dalvir S. Gill, Ph.D. has served as a director of our Company since March 2016. Mr. Gill has served as the Chief Executive Officer and a director of TransCelerate BioPharma, Inc., a nonprofit organization focused on improving the health of people around the world by simplifying and enhancing the research and development of innovative new therapies since January 2013. Previously, he was the President of Phase II-IV Drug Development at PharmaNet-i3, an international contract research organization, from July to December 2012. Dr. Gill earned his B.Sc. in Applied Biology from the University of Hertfordshire and his Ph.D. in Pathobiology from the Royal Free Hospital School of Medicine, University of London. He also holds a diploma in the health economics of pharmaceuticals from the executive program of the Stockholm School of Economics. Dr. Gill has more than 25 years of drug development experience. We believe that Dr. Gill brings strategic insight and leadership and a wealth of experience in the pharmaceutical industry to the Board of Directors, as well as knowledge of the regulatory and clinical requirements associated with the development of new drug compounds.

Jeffrey S. Mathiesen has served as a director of our Company since September 2015. He has served as Chief Financial Officer of Gemphire Therapeutics Inc., a publicly traded biopharmaceutical company since January 2015. Previously, he served as Chief Financial Officer of Sunshine Heart, Inc., a publicly traded medical device company, from March 2011 to January 2015. From December 2005 to April 2010, Mr. Mathiesen served as Vice President and Chief Financial Officer of Zareba Systems, Inc., a manufacturer and marketer of medical products, perimeter fencing and security systems that was purchased by Woodstream Corporation in April 2010. Mr. Mathiesen has held executive positions with publicly traded companies dating back to 1993, including vice president and chief financial officer positions. Mr. Mathiesen also serves as a director of NeuroOne, Inc., a publicly traded medical device company. Mr. Mathiesen holds a B.S. in Accounting from the University of South Dakota and is also a Certified Public Accountant. We believe that Mr. Mathiesen brings financial insight and leadership and a wealth of experience in capital markets to the Board of Directors, as well as knowledge of public company accounting and financial reporting requirements.

J. Robert Paulson, Jr., J.D., M.B.A. has served as a director of our Company since September 2015. Mr. Paulson has served as President, CEO, and a director of NxThera, Inc., a venture-funded medical device company developing a novel convective water vapor energy system to treat a variety of endourological conditions, including benign prostatic hyperplasia (BPH) and prostate cancer since 2009. Previously, he was President, CEO and a director of Restore Medical Inc. from 2005 until its acquisition by Medtronic in July 2008. He was CFO and VP of Global Marketing for Endocardial Solutions, which was acquired by St. Jude Medical in 2005. Before that, he was the Sr. VP/General Manager of Advanced Bionics, and held several executive positions with Medtronic, including VP/General Manager of the Surgical Navigation Technologies business, VP Corporate Strategy, and Director of Corporate Development. Mr. Paulson has held senior positions in marketing, corporate development, legal and finance at General Mills, and practiced corporate, M&A and securities law with the Minneapolis law firm of Lindquist & Vennum. He has served as a director of Veran Medical since 2008, and is a former director of Ablation Frontiers, Vascular Solutions and Medical CV. We believe that Mr. Paulson brings strategic insight and leadership and a wealth of experience in healthcare to the Board of Directors, as well as knowledge of capital markets and early stage companies.

Required Vote and Board Recommendation

Directors are elected by a plurality of votes present and entitled to vote. Provided that a quorum is present, the two nomineesnominee receiving the highest number of votes will be elected. The votes cannot be cast for a greater number of persons than two.one.

The Board of Directors unanimously recommends that you vote “FOR” each of the nomineesnominee
for Class II DirectorsI Director listed above.

CORPORATE GOVERNANCE

In accordance with applicable laws and our bylaws, the business and affairs of the Company are governed under the direction of the Board of Directors. The system of governance practices we follow is set forth in our corporate governance guidelines and in the charters of each of the committees of the Board of Directors. The corporate governance guidelines set forth the practices our board will follow with respect to its duties, committee matters, director qualifications and selection process, director compensation, director share ownership, director orientation and continuing education, executive evaluation, management succession and annual evaluation of the Board of Directors and committees. We also have adopted a code of business conduct and ethics relating to the conduct of our business by our employees, officers and directors. The corporate governance documents of the Company are reviewed periodically to ensure effective and efficient governance and compliance in a timely manner with all laws.

Corporate governance information, including the corporate governance guidelines, committee charters and the code of business conduct and ethics applicable to our directors, officers and employees is posted on our website at www.sunbiopharma.com under the “Investors” page. We plan to post to our website at the address described above any future amendments or waivers to our code of ethics and business conduct.

Board LeadershipLeadership Structure

OurOur Board of Directors is led by our Executive Chairman, Michael T. Cullen. As Executive Chairman, Dr. Cullen (a) has the responsibility to callis responsible for calling and presidepresiding over meetings of ourthe Board, of Directors, (b) presidepresides over our annual meetings of stockholders, (c) hasholds primary responsibility in setting boardBoard agendas, in consultation with our Chief Executive Officer, (d) has the ability to represent us with external stakeholders if approved by ourstakeholders. On October 31, 2018, the Board elected Dr. Cullen to fill vacancies in the additional roles of Directors,President and (e) has the responsibility to seek input from other independent directors, facilitate discussions among the independent directors, and communicate such viewpoints to our Chief Executive Officer. We believe that this leadership structure (a) enhanceshaving the same individual serve as Chairman of the Board and Chief Executive Officer is appropriate as it both maintains the functionality of our Board of Directors (b) strengthens communications between the board and our Chief Executive Officer, and (c) strengthens our board’s independence from management. In addition, this structure allows our Chief Executive Officer, David B. Kaysen, to focus his efforts on running our business and managing us in the best interestsis an efficient use of our stockholders.Company resources. Our Board of Directors believes that its current structure is the appropriate one at this time.has not designated a lead independent director.

Nominating Process and Board Diversity

The Nominating and Governance Committee generally identifies director candidates based upon suggestions from current directors and senior management, recommendations by stockholders or use of a director search firm. Stockholders who wish to suggest qualified candidates may write to the attention of the chairman of our Nominating and Governance Committee at Sun BioPharma, Inc., 712 Vista Boulevard #305, Waconia, Minnesota 55387. All recommendations should state in detail the qualifications of such person for consideration by the committee and should be accompanied by an indication of the recommended person’s willingness to serve if elected. The committee will consider candidates recommended by stockholders in the same manner that it considers all director candidates.

Candidates for director are reviewed in the context of the current composition of our Board of Directors, our operations and the long-term interests of our stockholders. We do not have a policy regarding the consideration of diversity in identifying director nominees.

Director Independence

Our Board of Directors has reviewed the materiality of any relationship that each of our directors has with us, either directly or indirectly. Based on this review, our Board of Directors has determined that Messrs. Gill, Mathiesen, Paulson, Schaffer and Schemel are “independent directors” as defined under the applicable rules of The Nasdaq Stock Market, LLC, which we have voluntarily adopted as our standard for director independence.

Communications with our Board of Directors

You may contact our Board of Directors or any director by mail addressed to the attention of our Board of Directors or the specific director identified by name or title, at 712 Vista Boulevard #305, Waconia, Minnesota 55387. All communications will be submitted to our Board of Directors or the specified director on a periodic basis.

Board Meetings and Attendance

Our Board of Directors held nine meetings during 2017.2018. Each director, other than Mr. Schemel, attended at least 75% of the meetings of our Board of Directors and the committees on which he or she served held during their service as a director or member of the committee in the year ended December 31, 2017.2018.

Director Attendance at Annual Meeting

We do not have a formal policy regarding attendance of directors at our annual meeting of stockholders. FiveTwo directors were present at our annual meeting of stockholders held in 2017.2018.

Committees of the Board of Directors

Our Board of Directors has established three standing committees: Audit, Compensation, and Nominating and Governance. The membership of each committee is as follows:

Audit Committee

The Audit Committee’s primary functions, among others, are to: (a) assist the Board of Directors in discharging its statutory and fiduciary responsibilities with regard to audits of the books and records of our Company and the monitoring of its accounting and financial reporting practices; (b) carry on appropriate oversight to determine that our Company and its subsidiaries have adequate administrative and internal accounting controls and that they are operating in accordance with prescribed procedures and codes of conduct; and (c) independently review our Company’s financial information that is distributed to stockholders and the general public. The Audit Committee held fourfive meetings during 2017.2018. The Audit Committee has a charter, which is available on our website at www.sunbiopharma.comwww.sunbiopharma.com.

All of the members of the Audit Committee meet the requirements for financial literacy under the applicable rules and regulations of the SEC. Our Board of Directors has determined that Jeffrey S. Mathiesen is qualified to serve as an audit committee financial expert, as that term is defined under the applicable rules of the SEC. Each member of the Audit Committee satisfies the independence requirements of Rule 10A-3(b)(1) of the Securities Exchange Act.

AUDIT COMMITTEE REPORT

In accordance with its written charter adopted by the Board of Directors, (the “Board”), as amended, the Audit Committee assists the Board with fulfilling its oversight responsibility regarding the quality and integrity of the accounting, auditing and financial reporting practices of the Company.

In discharging its duties, the Audit Committee:

Based upon the review and discussions referred to above, the Audit Committee recommended to the Board of Directors that the audited financial statements be included in the Company’sCompany’s Annual Report on Form 10-K for the fiscal year ended December 31, 20172018 to be filed with the Securities and Exchange Commission.

Compensation Committee

The Compensation Committee reviews and recommends to our Board of Directors on an annual basis the goals and objectives relevant to the annual compensation of our executive officers in light of their respective performance evaluations. Our Compensation Committee is responsible for administering our 2011 Equity Incentive Plan (“2011 Plan”), as amended and 2016 Omnibus Incentive Plan (“2016 Plan”), including approval of individual grants of stock options and other awards. The Compensation Committee held sixfour meetings during 2017.2018. The Compensation Committee has a charter, which is available on our website at www.sunbiopharma.com.

Nominating and Governance Committee

The Nominating and Governance Committee is primarily responsible for identifying individuals qualified to serve as members of our Board of Directors, recommending individuals to our Board of Directors for nomination as directors and committee membership, reviewing the compensation paid to our non-employee directors and recommending adjustments in director compensation, as necessary, in addition to overseeing the annual evaluation of our Board of Directors. The Nominating and Governance Committee held one meeting during 2017.2018. The Nominating and Governance Committee has a charter that is available on our website at www.sunbiopharma.com.

Role of the Board in Risk Oversight

One of the key functions of our Board of Directors is informed oversight of our risk management process. The Board of Directors does not have a standing risk management committee, but rather administers this oversight function directly through the Board of Directors as a whole, as well as through various standing committees of our Board of Directors that address risks inherent in their respective areas of oversight. In particular, our Board of Directors is responsible for monitoring and assessing strategic risk exposure and our Audit Committee has the responsibility to consider and discuss our major financial risk exposures and the steps our management has taken to monitor and control these exposures, including guidelines and policies to govern the process by which risk assessment and management is undertaken. The Audit Committee also monitors compliance with legal and regulatory requirements. Our Nominating and Governance Committee monitors the effectiveness of our corporate governance practices, including whether they are successful in preventing illegal or improper liability-creating conduct. Our Compensation Committee assesses and monitors whether any of our compensation policies and programs has the potential to encourage excessive risk-taking.

Certain RelationshipsRelationships and Related Party Transactions

The following is a summary of transactions since January 1, 20162017 to which our Company has been a party and in which the amount involved exceeded $8,000,$13,000, which is approximately 1% of the average of our total assets as of the ends of our last two completed fiscal years, and in which any of our directors, executive officers, or beneficial holdersowners of more than 5%10% of our capital stock had or will have a direct or indirect material interest, other than the compensation arrangements that are described under the heading “Executive Compensation: Employment Agreements” below.

Our Chief Medical Officer, Suzanne Gagnon, is also a member of our Board of Directors. We are party to an employment agreement with Dr. Gagnon in substantially the same form as the employment agreements with the Executives described above under the heading “Executive Compensation: Employment Agreements.” Dr. Gagnon is eligible to participate in the other compensation and benefit programs generally available to our employees. Her employment agreement also includes customary confidentiality, non-competition and non-solicitation covenants. During 20162017 and 2017,2018, Dr. Gagnon received compensation from the Company amounting to $177,000$195,000 and $195,000,$207,700, respectively. Under her employment agreement in effect for 2016, Dr. Gagnon was entitled to receive an initial annualized base salary equal to $360,000. Her employment agreement was amended to reduce her annualized base salary to $270,000, effective as of October 1, 2017. Dr. Gagnon’s employment agreement, as amended, would have entitled her to a potential payment equal to $385,046, which amount was based on the amount of compensation that she had accrued prior to September 30, 2017, as a result of any change of control of Qualified Offering (described further below) occurring on or before June 30, 2018. However, Dr. Gagnon waived all right to receive the potential payment pursuant to a waiver and third amendment to her employment agreement that became effective in February 2018.

Certain directors and executive officers participated in various debt and equity offerings during the two years ended December 31, 2018. The table below summarizes those securities purchases:

Limitation of Liability of Directors and Officers and Indemnification

Our certificate of incorporation limits the liability of the directors to the fullest extent permitted by Delaware law.

Our bylaws provide that we will indemnify and advance expenses to the directors and officers to the fullest extent permitted by law or, if applicable, pursuant to indemnification agreements. They further provide that we may choose to indemnify other employees or agents of our Company from time to time. The Delaware General Corporation Law and the bylaws also permit us to secure insurance on behalf of any officer, director, employee or other agent for any liability arising out of his or her actions in connection with their services to our Company, regardless of whether the bylaws permit indemnification. We maintain a directors’ and officers’ liability insurance policy.

AtAt present there is no pending litigation or proceeding involving any of the current or former directors or officers as to which indemnification is required or permitted, and we are not aware of any threatened litigation or proceeding that may result in a claim for indemnification.

Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the SEC this indemnification is against public policy as expressed in the Securities Act and is therefore unenforceable.

Related Person Transaction Approval Policy

Our Board of Directors has adopted a written policy regarding transactions with related persons, which we refer to as our related party transaction approval policy. Our related party transaction approval policy requires that any executive officer proposing to enter into a transaction with a “related party” generally must promptly disclose to our Audit Committee the proposed transaction and all material facts with respect thereto. In reviewing a transaction, our Audit Committee will consider all relevant facts and circumstances, including (1) the commercial reasonableness of the terms, (2) the benefit and perceived benefits, or lack thereof, to us, (3) the opportunity costs of alternate transactions and (4) the materiality and character of the related party’s interest, and the actual or apparent conflict of interest of the related party.

Our Audit Committee will not approve or ratify a related party transaction unless it determines that, upon consideration of all relevant information, the transaction is beneficial to our Company and stockholders and the terms of the transaction are fair to our Company. No related party transaction will be consummated without the approval or ratification of our Audit Committee. It will be our policy that a director will recuse him- or herself from any vote relating to a proposed or actual related party transaction in which they have an interest. Under our related party transaction approval policy, a “related party” includes any of our directors, director nominees, executive officers, any beneficial owner of more than 5% of our common stock and any immediate family member of any of the foregoing. Related party transactions exempt from our policy include transactions available to all of our employees and stockholders on the same terms and transactions between us and the related party that, when aggregated with the amount of all other transactions between us and the related party or its affiliates, involved less than one percent of the average of our Company’s total assets at yearend for the last two completed fiscal years.

Compensation Committee Interlocks and Insider Participation

None of the members of the Compensation Committee nor any director nominee proposed to become a member of the Compensation Committee is or has at any time during the last completed fiscal year been an officer or employee of our Company. None of our executive officers has served as a member of the board of directors or as a member of the compensation or similar committee, of any entity that has one or more executive officers who served on our Board of Directors during the last completed fiscal year.

None of the members of the Compensation Committee is or has at any time during the last completed fiscal year been an officer or employee of our Company. None of our executive officers has served as a member of the board of directors, or as a member of the compensation or similar committee, of any entity that has one or more executive officers who served on our Board of Directors or Compensation Committee during the last completed fiscal year.

DIRECTORDIRECTOR COMPENSATION

Directors who are also our employees receive no additional compensation for serving on our Board of Directors. During 2017,2018, our Company reimbursed non-employee directors for out-of-pocket expenses incurred in connection with attending meetings of our Board of Directors and its committees. Our non-employee directors received no compensation during the year ended December 31, 2017.2018.

On March 19, 2019, the Compensation Committee of the Board of Directors approved a compensation program for our non-employee directors effective for 2019 and future years, consisting of annual awards of options to purchase common stock. Each non-employee director will be eligible to receive an option by dividing a target dollar amount by the Black-Scholes value of a share of our common stock as of the date of grant. The target dollar amount for each director will equal (i) $35,000 for service as a non-employee director, plus (ii) $5,000 for each committee of which the director is expected to serve as chair. The resulting common stock option will be granted as soon as practicable after the completion of our annual meeting of stockholders and will be scheduled to vest in full on the day preceding the following annual meeting of stockholders.

The Compensation Committee also determined that each current non-employee director will receive a one-time grant of an option to purchase a number of shares of our common stock equal to $10,000 divided by the Black-Scholes value of a share of our common stock on the date of grant. Each such option will vest in three substantially equal installments on the first, second and third anniversaries of the dates of grant.

All options awarded to non-employee directors under the new compensation program will bear an initial exercise price equal to the fair market value of a share of our common stock on the grant date, as determined in accordance with the applicable equity incentive plan, and, once vested, will remain exercisable through the ten-year anniversary of the date of grant.

SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

The following table sets forth certain information with respect to the beneficial ownership of our outstanding common stock as of March 29, 20182019 by (i) each of our named executive officers;officers identified in the Summary Compensation Table below; (ii) each of our directors; (iii) all of our executive officers, directors and director nominees as a group; and (iv) each other beneficial owner of 5% or more of our outstanding common stock. Ownership percentages are based on 4,093,8525,070,341 shares of common stock outstanding as of the close of business on the same date.

Beneficial ownership is determined in accordance with the rules of the SEC. To our knowledge and subject to applicable community property laws, each of the holders of stock listed below has sole voting and investment power as to the stock owned unless otherwise noted. The table below includes the number of shares underlying options that are exercisable within 60 days from March 29, 2018.2019. Except as otherwise noted below, the address for each director or officer listed in the table is c/o Sun BioPharma, Inc., 712 Vista Blvd #305, Waconia, Minnesota 55387.

EXECUTIVE COMPENSATION

The following disclosure focuses on our named executive officers. For fiscal 2018 our “named executive officers” consisted of: Michael T. Cullen, Susan Horvath, David B. Kaysen and Scott Kellen.

Base salaries for each of our named executive officers were initially established based on arm’s-lengtharm’s-length negotiations with the applicable executive. Our Compensation Committee reviews our executive officers’ salaries annually. When negotiating or reviewing base salaries, the Compensation Committee expects to considerconsiders market competitiveness based on their marketthe experience of its members, the executive’s expected future contribution to our success and the relative salaries and responsibilities of our other executives. All three of our Company’s continuing executive officers were employed by the Company during the most recent completed fiscal year.

Summary Compensation Table

The following table provides information regarding the compensation earned for fiscal year 2017 and fiscal year 2016 by our named executive officers:officers for fiscal 2018 (collectively referred to as the “Executives”):

Outstanding Equity Awards as of December 31, 20172018

Employment Agreements

We areDuring 2018, we were party to employment agreements with our Executive Chairman, President and Chief Executive Officer, and Chief Financial Officer (collectively,each of the “Executives”).Executives. In addition to the specific terms summarized below, each of the named executive officers who continue to serve as an executive officer (collectively, the “Continuing Executives”) is eligible to participate in the other compensation and benefit programs generally available to our employees, including our other executive officers.officers, if any. Each such employment agreement also includes customary confidentiality, non-competition and non-solicitation covenants.

In accordance with the employment agreements, the base salary of each Executive is reviewed annually by the Compensation Committee of our Board of Directors. The committee may authorize an increase for the applicable year but may not reduce an Executive’sExecutive’s base salary below its then-current level other than with the Executive’s consent or pursuant to a general wage reduction in respect of substantially all of our executive officers.

In October 2017, we further amended the employment agreements with the Executives.Dr. Cullen, Mr. Kaysen and Mr. Kellen. For Dr. Cullen and Mr. Kaysen, the amendments established new annual base salaries representing a 25% reduction from prior levels, each effective as of October 1, 2017. Mr. Kellen’s annual base salary remained unchanged. Each amendment furtheralso discontinued the “accrued compensation” provision that had been introduced in earlier amendments to the Executives’their respective employment agreements.

As a result of the amendments, each of the Executives continuedDr. Cullen, Mr. Kaysen and Mr. Kellen continued to be eligible to receive a cash payment (each, a “Contingent Payment”) in an amount equal to the amount that previously accumulated under the “accrued compensation” provision through September 30, 2017. The cash payment would have become due upon a change of control (as defined in each employment agreement) or our issuance of equity securities (including any securities that are convertible into or exercisable for equity securities) resulting in gross cash proceeds of $10,000,000 or more (a “Qualified Offering”). If neither a change of control nor a Qualified Offering had occurred on or before June 30, 2018, then the right to cash payment would have been be forfeited.

If, on or before June 30, 2018, the Company had closed an underwritten public offering of its securities that includes shares of common stock (whether or not such offering is a Qualified Offering), including the offering contemplated by this prospectus, then each of the Executives would have, in lieu of cash payment, instead received one or more equity awards under the 2016 Plan. The equity awards would have been in the form of an option to purchase shares of common stock and a potential additional award of shares of common stock. Pursuant to the amendments, each Executive had agreed to automatically waive their rights to the cash payment discussed above in exchange for the equity awards. The number of shares underlying the potential stock option would have been determined at the time the Company closed an underwritten public offering and would have been based on the amount of each Employee’s potential cash payment amount (identified above) divided by the value of an option to purchase a single share of common stock determined using a Black-Scholes option valuation model. The exercise price for each option award would have equaled “fair market value” as of the grant date determined in accordance with the 2016 Plan. If the number of shares underlying the option award were limited by the 2016 Plan, then the remainder would have been issued in the form of a stock award.

Effective February 27, 2018, we entered into a Waiver and Third Amendment with each of the Executives,Dr. Cullen, Mr. Kaysen and Mr. Kellen, which waived all right to receive the Contingent Payment. These amendmentamendments also entitled Dr. Cullen, Mr. Kaysen and Mr. Kellenthem to new ten-yearcommon stock options to under our 2016 Plan to purchase up to 100,000 shares, 50,000 shares, and 25,000 shares of our common stock, respectively, exercisable for the following ten years at an exercisea price equal to $8.10 per share, representing fair market value as of the date of grant.

Executive Chairman, President and Chief Executive Officer

Under his original employment agreement, Dr. Cullen was entitled to receive an initial annualized base salary equal to $384,000. As discussed above, Dr. Cullen’sCullen’s employment agreement was amended to reduce his annualized base salary to $288,000, effective as of October 1, 2017. Notwithstanding the foregoing, Dr. Cullen received a portion of his monthly salary in cash and the remainder was accrued between October 1, 2015 and September 30, 2017. In lieu of the accrued amount, Dr. Cullen’s employment agreement had entitled him to a Contingent Payment equal to $410,136 as a result of any change of control or Qualified Offering on or before June 30, 2018, as discussed in more detail above. Dr. Cullen waived all right to receive the Contingent Payment in February 2018.

Dr.Dr. Cullen is eligible to receive an annual performance-based cash bonus with a target amount equal to no less than 45% of his base salary. Payment of the bonus amount will be subject to achievement of metrics to be established by our Board of Directors and Dr. Cullen’s continued employment with the Company through the end of the applicable cash bonus period. Neither our Board of Directors nor its Compensation Committee established such performance criteria for 20172018 and therefore no cash bonus was paid.

No change was made to Dr. Cullen’s employment agreement as a result of his election to serve in the additional roles of President and Chief Executive Officer

Under his in October 2018. Modifications to Dr. Cullen’s employment agreement Mr. Kaysen is entitled to receive an initial annualized base salary equal to $420,000. Notwithstandingwere discussed at the foregoing, Mr. Kaysen received a portion of his monthly salary in cash and the remainder was accrued between March 1, 2016 and September 30, 2017. In lieumeeting of the accrued amount, Mr. Kaysen’s employment agreement had entitled himCompany’s Compensation committee on March 19, 2019 but the decision to a Contingent Payment equal to $201,599 as a result of any change of control or Qualified Offering on or before June 30, 2018, as discussed in more detail above. Mr. Kaysen waived all right to receive the Contingent Payment in February 2018.

Mr. Kaysen is eligible to receive an annual performance-based cash bonus with a target amount equal to no less than 60% of his base salary. Payment of the bonus amount will be subject to achievement of metrics to be established by our Board of Directors and Mr. Kaysen’s continued employment with the Company through the end of the applicable cash bonus period. Neither our Board of Directors nor its Compensation Committee established such performance criteria for 2017 and therefore no cash bonusmodified was paid. Mr. Kaysen is also eligible to receive cash bonuses of (i) $260,000 upon the completion of a Qualified Financing and (ii) $36,000 upon the completion of certain other objectives specified in his employment agreement. Mr. Kaysen had satisfied the objectives of the bonus amount of $36,000 during the first quarter of 2016, payment of which has also been deferred until the completion of a Qualified Financing.

In December 2016, Mr. Kaysen received an option to purchase an aggregate of 80,000 shares of our common stock at an exercise price of $15.10 per share. Such option, vests proportionately based on cash proceeds received by, or contractually obligated to be remitted to, the Company after June 1, 2016 and before December 31, 2018 from any transaction, excluding certain internal operating-related cash flows. The performance criteria was 22% satisfied on the date of grant, resulting in vesting of the option as to 17,600 shares. On March 17, 2017, the Compensation Committee certified the further satisfaction of the performance criteria as a result of the sale of convertible promissory notes in February and March 2017 resulting in gross proceeds of $3.1 million. Upon completion of the sale of those convertible promissory notes, the option became exercisable for a total of 42,400 shares or 53% of the total underlying shares.later meeting.

Chief Financial Officer

Under hisher employment agreement, Mr. KellenMs. Horvath is entitled to receive an initial annualized base salary equal to $240,000. Notwithstanding the foregoing, Mr. Kellen received a portion of his monthly salary in cash and the remainder was accrued between March 1, 2016 and September 30, 2017. In lieu of the accrued amount, Mr. Kaysen’s employment agreement had entitled him to a Contingent Payment equal to $97,208 as a result of any change of control or Qualified Offering on or before June 30, 2018, as discussed in more detail above. Mr. Kellen waived all right to receive the Contingent Payment in February 2018.

Mr. Kellen $225,000. Ms. Horvath also is eligible to receive an annual performance-based cash bonus with a target amount equal to no less than 40% of hisher base salary. Payment of the bonus amount will be subject to achievement of metrics to be established by our Board of Directors and Mr. Kellen’sMs. Horvath’s continued employment with the Company through the end of the applicable cash bonus period. Neither our Board of Directors nor its Compensation Committee established such performance criteria for 20172018 and therefore no cash bonus was paid.

In December 2016, Mr. Kellen received an option to purchase an aggregate of 30,000 shares of our common stock at an exercise price of $15.10 per share. Such option, vests proportionately based on cash proceeds received by, or contractually obligated to be remitted to, the Company after June 1, 2016 and before December 31, 2018 from any transaction, excluding certain internal operating-related cash flows. The performance criteria was 22% satisfied on the date of grant, resulting in vesting of the option as to 6,600 shares. On March 17, 2017, the Compensation Committee certified the further satisfaction of the performance criteria as a result of the sale of convertible promissory notes in February and March 2017 resulting in gross proceeds of $3.1 million. Upon completion of the sale of those convertible promissory notes, the option became exercisable for a total of 15,900 shares or 53% of the total underlying shares.

Potential Payments Upon Termination or Change-in-Control

Under their respective employment agreements, if an Executives’Dr. Cullen or Ms. Horvath’s employment is terminated by us for any reason other than for “cause” (as defined in the applicable employment agreement) or by the Executivehim or her for “good reason” (as defined in the applicable employment agreement), then the Executivehe or she will be eligible to receive an amount equal to histheir respective annualized salary plus an amount equal to a prorated portion of histheir cash bonus target, if any, for the year in which the termination occurred, in addition to other amounts accrued on or before the date of termination. If any such termination occurs within six months prior or two years after a “change of control” (as defined in the applicable employment agreement), then Dr. Cullen and Mr. KellenMs. Horvath would instead receive an amount equal to hishis/her respective annualized salary, plus an amount equal to hishis/her full cash bonus target for the year in which the termination occurred. Upon a similar termination, Mr. Kaysen would receive an amount equal to 1.5 times his annualized salary, plus an amount equal to his full cash bonus target.

EQUITY COMPENSATION PLAN INFORMATION

The following table presents certain information regarding our equity compensation plans as of December 31, 2018.

PROPOSAL 2:2:
RATIFICATION OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The Audit Committee has selected Cherry Bekaert LLP to serve as our independent registered public accounting firm for fiscal year 2018,2019, and the Board of Directors is asking stockholders to ratify that selection. Although current law, rules and regulations, as well as the Audit Committee charter, require our independent registered public accounting firm to be supervised by the Audit Committee and recommended to the Board of Directors for appointment and, if necessary, removal, our Board of Directors considers the selection of an independent registered public accounting firm to be a matter of stockholder concern and considers this proposal to be an opportunity for stockholders to provide direct feedback. Cherry Bekaert LLP has served as the Company’s independent registered public accounting firm since 2015.

Notwithstanding its selection of Cherry Bekaert LLP, the Audit Committee, in its discretion, may appoint another independent registered public accounting firm at any time during the year if the committee believes that such a change would be in the best interests of our Company and its stockholders. If the appointment of Cherry Bekaert LLP is not ratified by our stockholders, the Audit Committee may reconsider whether it should appoint another independent registered public accounting firm. Representatives of Cherry Bekaert LLP are not expected to be present at the Annual Meeting.

Required Vote and Board RecommendationRecommendation

Provided that a quorum is present approval ofat the Annual Meeting, this proposal will requirebe approved if it received the numberaffirmative vote of votes cast in favora majority of the shares of stock represented at the meeting and entitled to exceedvote on the number of votes cast in opposition.proposal.

The Board of Directors unanimously recommends that you vote “FOR” the ratification of the selection of Cherry Bekaert LLP as the Company’s independent registered public accounting firm for 20182019.

Audit Fees

Cherry Bekaert LLP served as our independent registered public accounting firm for the yearyears ended December 31, 20172018 and 2016.2017. The following table presents the aggregate fees for professional services provided by Cherry Bekaert LLP related to 20172018 and 2016:2017:

“Audit Fees” consisted of fees for the audit of our annual consolidated financial statements, including audited consolidated financial statements presented in our annual report on Form 10-K, review of the consolidated financial statements presented in our quarterly reports on Form 10-Q and services that are normally provided by the independent registered public accountants in connection with statutory and regulatory filings or engagements for those fiscal years. This category also includes advice on audit and accounting matters that arose during, or as a result of, the audit or the review of interim financial statements and statutory audits required by non-U.S. jurisdiction.

Pre-approval Policy

The Audit Committee has established a policy governing our use of the services of our independent registered public accountants. Under the policy, the Audit Committee is required to pre-approve all audit and permitted non-audit services performed by our independent registered public accountants in order to ensure that the provision of such services does not impair the public accountants’ independence. In 2017,2018, all fees identified above under the captions “Audit Fees” that were billed by Cherry Bekaert LLP were approved by the Audit Committee in accordance with SEC requirements.

PROPOSAL 3:
ADVISORY VOTE TO APPROVE EXECUTIVE COMPENSATION

The Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 (the “Dodd-Frank Act”) enables the stockholders of the Company to vote to approve, on a non-binding basis, the compensation of the Company’s named Executive Officers as disclosed pursuant to Item 402 of Regulation S-K of the SEC. The Company was previously exempt from this requirement as a result of its “emerging growth company” status, which terminated on December 31, 2018.

Compensation Philosophy and Compensation of our Named Executive Officers

The Company seeks to align the interests of its named executive officers with the interests of its stockholders. Therefore, the Company’s compensation programs are designed to reward the named executive officers for the achievement of strategic and operational goals and the achievement of increased stockholder value, while at the same time avoid encouraging of unnecessary or excessive risk-taking. The Board of Directors and its Compensation Committee believe that the Company’s compensation policies and procedures are competitive and focused on performance and are strongly aligned with the long-term interest of its stockholders.

Form of Resolution

This proposal, commonly known as a “Say-on-Pay” proposal, gives you the opportunity to express your views regarding the compensation of our named executive officers by voting to approve or not approve such compensation as described in this proxy statement. This vote is advisory and will not be binding upon the Board of Directors or its Compensation Committee. However, both will take into account the outcome of the vote when considering future executive compensation arrangements. The vote on this resolution is not intended to address any specific element of compensation, but rather relates to the overall compensation of the named executive officers, as described in this proxy statement in accordance with the compensation disclosure rules of the Securities and Exchange Commission.

Stockholders are being asked to vote “FOR” or “AGAINST” the following resolution at the Annual Meeting:

Required Vote and Board Recommendation

Provided a quorum is present at the Annual Meeting, this proposal will be approved if it received the affirmative vote of a majority of the shares of stock represented at the meeting and entitled to vote on the proposal.

The Board of Directors recommends that you vote “FOR” this Proposal 3.

PROPOSAL 4:
ADVISORY VOTE ON THE FREQUENCY
OF FUTURE ADVISORY VOTES ON EXECUTIVE COMPENSATION

The Dodd-Frank Act requires that the Company provide stockholders with the opportunity to vote, on a non-binding advisory basis, for their preference as to how frequently the Company should consult the stockholders through an advisory Say-on-Pay vote. Stockholders may indicate whether they would prefer that the Company conduct future Say-on-Pay votes every year, every two years or every three years. Stockholders also may abstain from casting a vote on this proposal.

The Board of Directors and its Compensation Committee believes that a Say-on-Pay vote that occurs once every other year is the most appropriate option for the Company and therefore recommends that you vote in favor of conducting a Say-on-Pay vote every two years. The Board’s decision was based on our goal to align the interests of executive officers with the interests of our stockholders, ensure the long-term commitment of our management team, and ensure accountability for both our overall performance and the individual’s performance and contribution. We believe holding that vote every two years provides the most effective timeframe because it allows our Board and Compensation Committee sufficient time to engage with our stockholders following each such vote in order to understand any concerns they may have, and to respond with any changes to the compensation of our executive officers and/or related disclosure deemed appropriate in response to the results of an advisory vote.

This vote is advisory, which means that is not binding on the Board of Directors or its Compensation Committee. We recognize that our stockholders may have different views as to the best approach to the frequency of the Say-on-Pay vote. The Board of Directors and Compensation Committee will carefully review the outcome of this advisory vote. However, when determining the frequency of future Say-on-Pay votes, the Board of Directors and its Compensation Committee may decide that it is in the stockholders’ long-term best interest to hold a Say-on-Pay vote more or less frequently than the frequency recommended by the stockholders.

The proxy card provides stockholders with the opportunity to choose among four options:

Stockholders are not being asked to approve or disapprove the recommendation of the Board of Directors.

Required Vote and Board Recommendation

The option that receives the highest number of votes will be deemed to be the recommendation of our stockholders.

The Board of Directors recommends that you vote “TWO YEARS” for this Proposal 4.

SECTION 16(a) BENEFICIAL OWNERSHIP REPORTING COMPLIANCE

Section 16(a) of the Securities and Exchange Act of 1934 requires that our directors, and executive officers and beneficial owners of more than 10% of our common stock file initial reports of ownership and reports of changes in ownership with the SEC. Directors, and executive officers and beneficial owners of greater than 10% of our common stock are required to furnish us with copies of all Section 16(a) forms they file. Based solely on a review of the copies of such forms furnished to us and written representations from our directors and executive officers, all Section 16(a) filing requirements were met for the fiscal year ended December 31, 2017,2018 except forfor: one Form 4 reportingreport by Ms. Gagnon relating to one transaction involving the receipt of a common stock option awardaward; one report by Mr. Schaffer relating to Dr. Gagnon.three transactions involving the acquisition of common stock and warrants from the Company and the conversion of an outstanding promissory note; one report by Mr. Kaysen relating to two transactions involving the acquisition of common stock and warrants from the Company; and two reports by Ryan R. Gilbertson, the first relating to one transaction involving the conversion of an outstanding promissory note, and the second relating to two transactions involving the sale of the resulting common stock and warrants.

OTHER MATTERS

The Board of Directors is not aware of any matters that are expected to come before the Annual Meeting other than those referred to in this proxy statement. If any other matter should come before the Annual Meeting, the persons named in the accompanying proxy intend to vote the proxies in accordance with their best judgment.

SUBMISSION OF STOCKHOLDER PROPOSALS AND NOMINATIONS

Stockholder proposals intended to be presented at the annual meeting of stockholders to be held in the year 20192020 that are requested to be included in the proxy statement for that meeting must be received by us at our principal executive office no later than December 17, 2018.18, 2019. We must receive any other stockholder proposals intended to be presented, and any director nominees for election, at the annual meeting of stockholders in the year 20192020 at our principal executive office no earlier than January 22, 201912, 2020 and no later than February 21, 2019.11, 2020. Upon timely receipt of any such proposal containing the information required by our bylaws, as amended from time to time, we will determine whether or not to include such proposal in the proxy statement and proxy in accordance with applicable regulations governing the solicitation of proxies.

Our management knows of no matters other than the foregoing to be brought before the Annual Meeting. However, this proxy gives discretionary authority in the event that additional matters should be presented.

ADDITIONAL INFORMATION

OurWe have adopted a procedure approved by the Securities and Exchange Commission called “householding,” by which certain stockholders who do not participate in electronic delivery of proxy materials but who have the same address and appear to be members of the same family receive only one copy of our annual report and proxy statement. Each stockholder participating in householding continues to receive a separate proxy card. Householding reduces both the environmental impact of our annual meetings and our mailing and printing expenses.

If you would like to change your householding election, request that a single copy of the proxy materials be sent to your address, or request a separate copy of the proxy materials, please contact Broadridge Financial Solutions, Inc., by calling (866) 540-7095 or by writing to Broadridge Householding Department, 51 Mercedes Way, Edgewood, New York 11717. We will promptly deliver the notice of internet availability or proxy materials to you upon receipt of your request. If you hold your shares in street name, please contact your bank, broker, or other record holder to request information about householding.

ADDITIONAL INFORMATION

The Company’s Annual Report on Form 10-K including our financial statement andfor the notes thereto, for thefiscal year ended December 31, 2017,2018, accompanies the delivery of this proxy statement and a copy of such annual report, as filed with the SEC,Securities and Exchange Commission, is also available on the SEC’s Internet site, Commission’ website, www.sec.gov,, and our corporate website, www.sunbiaopharma.com, underwww.sunbiopharma.com (under “Investor Relations.”

We will provideRelations”). In addition, a copy of the Annual Report on Form 10-K, and/or theas amended, may be sent to any stockholder without charge (except for exhibits, to the Form 10-K upon written request and payment of specified fees. The written requestif requested, for such Form 10-K and/or Exhibits shouldwhich a reasonable fee will be directed to Scott Kellen,charged), our Chief Financial Officer and Secretary at:

Such request must set forth a good faith representation that the requesting party was a holder of record or a beneficial owner of our common stock as of the Record Date. The annual report on Form 10-K complete with exhibits and the proxy statement are also available at no cost through the EDGAR database available from the Securities and Exchange Commission’s internet site (www.sec.gov), and at https://www.rdgir.com/sun-biopharma-inc.

Please Mark, Date, Sign and Return Promptly in the Enclosed Envelope.

Annual Meeting Proxy Card - Sun BioPharma, Inc. Common Stock

DETACH PROXY CARD HERE TO VOTE BY MAIL

The Board of Directors recommends you vote FOR all of the following director nominees:

(1)     Election of Class IIDirectors:

FOR ALL NOMINEES LISTED BELOW (except as marked to the contrary below)

WITHHOLD AUTHORITY TO VOTE FOR ALL NOMINEES LISTED BELOW

The Board of Directors recommends you vote FOR proposals 2:

(2)     To ratify the selection of Cherry Bekaert LLP as the independent registered public accounting firm for the fiscal year ending December 31, 2018.

NOTE: If any other matters properly come before the Annual Meeting of Stockholder calling for a vote of stockholders, then the shares represented by this proxy may be voted by the proxy holders in accordance with their best judgment.

SUN BIOPHARMA,, INC.

Annual Meeting of Stockholders

May 22, 201821, 2019

Important Notice Regarding the Availability of Proxy Materials for the Annual Meeting of Stockholders
To Be Held on May 22, 201821, 2019

The Notice, Proxy Statement and Annual Report for 20182019 are available at

https://www.rdgir.com/sun-biopharma-inc

SUN BIOPHARMA, INC.

THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS

The undersignedundersigned hereby appoints David B. KaysenMichael T. Cullen and Scott Kellen,Susan Horvath, and each of them, as proxies, each with the power to appoint his substitute, and hereby authorizes such proxies to represent and to vote, as designated on the reverse, all shares of common stock of Sun BioPharma, Inc., that the undersigned is/are entitled to vote at the Annual Meeting of Stockholders to be held on May 22, 2018,21, 2019, located at the offices of Faegre Baker Daniels LLP, 2200 Wells Fargo Center, 90 South Seventh Street, Minneapolis, Minnesota and any adjournment or postponement thereof upon matters set forth in the proxy statement and, in their discretion, upon any other business as may properly come before the meeting.

This proxy, when properly executed, will be voted in the manner directed herein. If no such direction is made, this proxy will be voted in accordance with the Board of Directors’Directors’ recommendations.

Please check here if you plan to attend the Annual Meeting of Stockholders on May 22, 201821, 2019 at 2:30 p.m. (Local Time).  ☐

(Continued and to be signed on Reverse Side)