In addition, if we are required to conduct additional clinical trials or other testing of our product candidates beyond those that we currently contemplate, if we are unable to successfully complete our clinical trials or other testing, if the results of these trials or tests are not positive or are only modestly positive or if there are safety concerns, we may:

Our product development costs will also increase if we experience delays in testing or approvals. We do not know whether any preclinical tests or clinical trials will be initiated as planned, will need to be restructured or will be completed on schedule, if at all. Significant preclinical or clinical trial delays also could shorten the patent protection period during which we may have the exclusive right to commercialize our product candidates. Such delays could allow our competitors to bring products to market before we do and impair our ability to commercialize our products and product candidates.

The completion rate of clinical studies of our products is dependent on, among other factors, the patient enrollment rate. Patient enrollment is a function of many factors, including:

Research programs to identify product candidates require substantial technical, financial and human resources, whether or not any product candidates are ultimately identified. Our research programs may initially show promise in identifying potential product candidates, yet fail to yield product candidates for clinical development for many reasons, including the following:

If we are unsuccessful in identifying and developing additional product candidates, our potential for growth may be impaired.

If approved for marketing, the commercial success of PAX-101 or any other product candidates we may develop or acquire will depend upon acceptance by the medical community, including physicians, patients and health care payors. The degree of market acceptance of PAX-101 or such other product candidate will depend on a number of factors, including:

If PAX-101 or any other product candidates we may develop or acquire is approved, but does not achieve an adequate level of adoption by physicians, health care payors and patients, we may not generate sufficient revenue and we may not be able to achieve or sustain profitability. Our efforts to educate the medical community and third-party payors on the benefits of such product candidate may require significant resources and may never be successful.

In addition, even if we obtain regulatory approvals, the timing or scope of any approvals may prevent or reduce our ability to commercialize such product candidate successfully. For example, if the approval

With respect to sales and marketing activities by us or any future partner, advertising and promotional materials must comply with FDA rules in addition to other applicable federal, state and local laws in the United States and similar legal requirements in other countries. In the United States, the distribution of product samples to physicians must comply with the requirements of the U.S. Prescription Drug Marketing Act. Application holders must obtain FDA approval for product and manufacturing changes, depending on the nature of the change. We may also be subject, directly or indirectly through our customers and partners, to various fraud and abuse laws, including, without limitation, the U.S. Anti-Kickback Statute, U.S. False Claims Act, and similar state laws, which impact, among other things, our proposed sales, marketing, and scientific/educational grant programs. If we participate in the U.S. Medicaid Drug Rebate Program, the Federal Supply Schedule of the U.S. Department of Veterans Affairs, or other government drug programs, we will be subject to complex laws and regulations regarding reporting and payment obligations. All of these activities are also potentially subject to U.S. federal and state consumer protection and unfair competition laws. Similar requirements exist in many of these areas in other countries.

In addition, our product labeling, advertising and promotion would be subject to regulatory requirements and continuing regulatory review. The FDA strictly regulates the promotional claims that may be made about prescription products. In particular, a product may not be promoted for uses that are not approved by the FDA as reflected in the product’s approved labeling. If we receive marketing approval for our product candidates, physicians may nevertheless legally prescribe our products to their patients in a manner that is inconsistent with the approved label. If we are found to have promoted such off-label uses, we may become subject to significant liability and government fines. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses, and a company that is found to have improperly promoted off-label uses may be subject to significant sanctions, including revocation of its marketing approval. The federal government has levied large civil and criminal fines against companies for alleged improper promotion and has enjoined several companies from engaging in off-label promotion. The FDA has also requested that companies enter into consent decrees of permanent injunctions under which specified promotional conduct is changed or curtailed.

If we or a regulatory agency discovers previously unknown problems with a product, such as adverse events of unanticipated severity or frequency, problems with the facility where the product is manufactured, or we or our manufacturers fail to comply with applicable regulatory requirements or GMP, we may be subject to the following administrative or judicial sanctions:

In the United States and some foreign jurisdictions, there have been a number of legislative and regulatory changes and proposed changes regarding the healthcare system that could prevent or delay marketing approval for our drug candidates, restrict or regulate post-approval activities and affect our ability to profitably sell our drug candidates. Legislative and regulatory proposals have been made to expand post-approval requirements and restrict sales and promotional activities for pharmaceutical products. We do not know whether additional legislative changes will be enacted, or whether the FDA regulations, guidance or interpretations will be changed, or what the impact of such changes on the marketing approvals of our drug candidates, if any, may be. In addition, increased scrutiny by the U.S. Congress of the FDA’s approval process may significantly delay or prevent marketing approval, as well as subject us to more stringent product labeling and post-marketing testing and other requirements.

In the United States, under the Medicare Modernization Act (or MMA)(“MMA”), Medicare Part D provides coverage to the elderly and disabled for outpatient prescription drugs by approving and subsidizing prescription drug plans offered by private insurers. The MMA also authorizes Medicare Part D prescription drug plans to use formularies where they can limit the number of drugs that will be covered in any therapeutic class. The Part D plans use their formulary leverage to negotiate rebates and other price concessions from drug manufacturers. Also under the MMA, Medicare Part B provides coverage to the elderly and disabled for physician-administered drugs on the basis of the drug’s average sales price, a price that is calculated according to regulatory requirements and that the manufacturer reports to Medicare quarterly.

Both Congress and the Centers for Medicare & Medicaid Services (or CMS)(“CMS”), the agency that administers the Medicare program, from time to time consider legislation, regulations, or other initiatives to reduce drug costs under Medicare Parts B and D. For example, under the 2010 Affordable Care Act, drug manufacturers are required to provide a 50% discount on prescriptions for branded drugs filled while the beneficiary is in the Medicare Part D coverage gap, also known as the “donut hole.” There have been legislative proposals to repeal the “non-interference” provision of the MMA to allow CMS to leverage the Medicare market share to negotiate larger Part D rebates. Further cost reduction efforts could decrease the coverage and price that we receive for our drug candidates and could seriously harm our business. Private payors often follow Medicare coverage policy and payment limitations in setting their own reimbursement rates, and any reduction in reimbursement under the Medicare program may result in a similar reduction in payments from private payors.

Our business relies on the license of data from the Ministry of Health, Republic of Malawi and Lwala Hospital (Soroti, Uganda). The loss of our key data may seriously impair our business and future viability, and could result in delays in developing, introducing or maintaining our product candidates and formulations until equivalent data, if available, is identified, licensed and integrated. In addition, any defects in the data we license could prevent the implementation or impair the functionality of our product candidates or formulation, delay new product or formulation introductions or injure our reputation.

Certain of our officers are not required to work exclusively for us. Each ofFor example, Michael Derby, our Executive Chairman of the Board and Zachary Rome, our Chief Operating Officer and a director, and Joseph

Our certificate of incorporation, bylaws and Delaware law contain or will contain provisions which could have the effect of rendering more difficult, delaying or preventing an acquisition deemed undesirable by our board of directors. Our corporate governance documents include or will include provisions:

These provisions, alone or together, could delay or prevent hostile takeovers and changes in control or changes in our management.

As a Delaware corporation, we are also subject to provisions of Delaware law, including Section 203 of the Delaware General Corporation law, which prevents some stockholders holding more than 15% of our outstanding common stock from engaging in certain business combinations without approval of the holders of substantially all of our outstanding common stock.

Any provision of our certificate of incorporation, bylaws or Delaware law that has the effect of delaying or deterring a change in control could limit the opportunity for our stockholders to receive a

These forward-looking statements are subject to a number of risks, uncertainties and assumptions, including those described in “Risk Factors” and elsewhere in this prospectus. Moreover, we operate in a very competitive and rapidly changing environment, and new risks emerge from time to time. It is not possible for us to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements we may make. In light of these risks, uncertainties and assumptions, the forward-looking events and circumstances discussed in this prospectus may not occur and actual results could differ materially and adversely from those anticipated or implied in our forward-looking statements.

You should not rely upon forward-looking statements as predictions of future events. Although we believe that the expectations reflected in our forward-looking statements are reasonable, we cannot guarantee

If you invest in our common stock in this offering, your interest will be immediately diluted to the extent of the difference between the initial public offering price per share of our common stock in this offering and the net tangible book value per share of our common stock after this offering. As of June 30, 2020,March 31, 2022, we had a historical net tangible book deficit of $(3,182,000)$     , or $(0.55)$     per share of common stock. Our net tangible book value represents total tangible assets less total liabilities and the net tangible book value of our preferred stock divided by the number of shares of common stock outstanding on June 30, 2020.March 31, 2022. Our pro forma net tangible book deficit as of June 30, 2020,March 31, 2022, before giving effect to this offering, but after giving effect to the Preferred Conversion, was $(0.3)$     million, or $(0.04)$     per share of our common stock.

After giving effect to the sale of shares of common stock in this offering at an assumed initial public offering price of $6.00$    per share (the midpoint of the price range set forth on the cover page of this prospectus) and after deducting the estimated underwriting discount and estimated offering expenses payable by us, our pro forma as adjusted net tangible book value as of June 30, 2020March 31, 2022, would have been approximately $12.7$    million, or $1.29$    per share. This represents an immediate increase in pro forma as adjusted net tangible book value of $1.33$    per share to existing stockholders and an immediate dilution of $4.71$     per share to new investors. The following table illustrates this per share dilution:

A $1.00 decrease in the assumed initial public offering price of $6.00$    per share (the midpoint of the price range set forth on the cover page of this prospectus) would decrease our pro forma as adjusted net tangible book value as of June 30, 2020March 31, 2022 after this offering by approximately $2.3$   million, or approximately $0.24$    per share, and would decrease dilution to investors in this offering by approximately $0.76$    per share, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same, after deducting the estimated underwriting discount and estimated offering expenses payable by us. A $1.00 increase in the assumed initial public offering price of $6.00$    per share (the midpoint of the price range set forth on the cover page of this prospectus) would decrease our pro forma as adjusted net tangible book value as of June 30, 2020March 31, 2022 after this offering by approximately $2.3$   million, or approximately $0.23$    per share, and would increase dilution to investors in this offering by approximately $0.77$    per share, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same, after deducting the estimated underwriting discount and estimated offering expenses payable by us. We may also increase or decrease the number of shares we are offering. An increase of 1,000,000 in the number of shares we are offering would increase our pro forma as adjusted net tangible book value as of June 30, 2020March 31, 2022 after this offering by approximately $5.6$    million, or approximately $0.39$    per share, and would increase dilution to investors in this offering by approximately $0.39$    per share, assuming the assumed initial public offering price per share remains the same, after deducting the estimated underwriting discount and estimated offering expenses payable by us. A decrease of 1,000,000 in the number of shares we are offering would decrease our pro forma as adjusted net tangible book value as of June 30, 2020March 31, 2022 after this offering by approximately $5.6$    million, or approximately $0.49$    per share, and would decrease dilution to investors in this offering by approximately $0.49$    per share, assuming the assumed initial public offering price per share remains the same, after deducting the estimated underwriting discount and estimated offering expenses payable by us. Each one million share increase in the number of shares offered by us together with a concomitant $1.00 increase in the assumed initial public offering price of $6.00$    per share (the midpoint of the estimated price range set forth on the cover page of this prospectus) would increase the pro forma as adjusted net tangible book value by $0.69$    per share and the dilution to new investors by $0.31$    per share, after deducting underwriting discounts and commissions and any estimated offering expenses payable by us.

We are an earlya clinical stage biopharmaceutical company focusing on the development of APTs,APT for the treatment of disorders with intractable neurologic symptoms, ranging from neurodevelopmental disorders, including ASD, FXTASto ME/CFS, a debilitating physical and HAT. Since our inception, wecognitive disorder believed to be viral in origin and now with rising incidence globally due to the long term effects of COVID-19. APTs have devoted substantiallybeen shown to block the effects of excess production and extracellular receptor activity of ATP, which acts as both the main energy molecule in all living cells and a peripheral and central nervous system neurotransmitter via receptors that are found throughout the nervous system. Excess purinergic signaling can offset homeostasis and trigger immune responses that result in localized and systemic increases in inflammatory chemokines and cytokines, ultimately stimulating ATP production. APTs may also impact immunologic and inflammatory mechanisms that may be causing or exacerbating symptoms in these seemingly unrelated disorders, which may be caused in part by similar mechanisms of ATP overproduction.

One of our efforts to business planning, research and development, recruiting management and technical staff, acquiring operating assets and raising capital. Our business is subject to significant risks and uncertainties and we will be dependent on raising substantial additional capital before it becomes profitable and it may never achieve profitability.

In February 2021, we announced positive topline data from our Phase 2 dose-ranging clinical trial evaluating PAX-101 (commonly known as intravenous suramin) for the treatment of the core symptoms of ASD, as described in more detail below. We are also focused onintend to submit data to support an NDA for PAX-101 under the FDA’s Tropical Disease Priority Voucher Program for the treatment of HAT, where we are seeking to leverageleveraging suramin’s historical use in this indication, and data that wetreating HAT outside of the United States. We have exclusively licensed directlyclinical data from certain academic or international government institutions to furtherpotentially accelerate PAX-101’s development plans in the U.S.United States through this regulatory program and seek approval in the United States for the treatment of East African HAT as early as 2024. We are also pursuing the development of next generation anti-purinergicAPT product development candidates for neurodevelopmental indications. These assetscandidates include PAX-102, our proprietary intranasal formulation of suramin, which is an exploratory program targetingas well as other new chemical entities that are highlymore targeted and selective antagonists of particular purinergicpurine receptor subtypes. We believe our lead drug candidate (suramin), if approved by the FDA, may be a significant advancement in the treatment of ASD and FXTAS.a potentially useful treatment for ME/CFS and LCS.

We have not generated any revenue to date and, through June 30, 2020,March 31, 2022, we had an accumulated deficit of approximately $2.7$17.1 million. To date, we have financed our operations through contributions from TardiMed.our prior members, the issuance of our convertible notes (the “2020 Notes”), and the issuance of our Simple Agreement for Future Equity (“SAFE”). We expect our expenses to increase significantly in connection with our ongoing activities to develop, seek regulatory approval and commercialization of PAX-101 and our other product candidates. Furthermore, we expect to incur additional costs associated with operating as a public company. Accordingly, we will likely need substantial additional financing to support our continuing operations. We will seek to fund our operations through public or private equity or debt financings or other sources. Adequate additional financing may not be available to us on acceptable terms, or at all. Our failure to raise capital as and when needed would have a negative impact on our financial condition and our ability to pursue our business strategy. We will need to generate significant revenues to achieve profitability, and we may never do so. Accordingly, there are material risks and uncertainties that raise substantial doubt about our ability to continue as a going concern.

General and administrative expenses for the six months ended June 30, 2020, as compared to the prior period, was due to anwere approximately $1.0 million increaseand $1.3 million for the three months ended March 31, 2022 and 2021, respectively. The $0.3 million decrease in general and administrative expenses was primarily due to decreases of $0.3 million of stock-based compensation related to the granting of approximately 787,000 stock options, approximatelyand $0.2 million of payroll and related costs,expenses, offset by an increase of $0.2 million for legal and approximately $0.3 million of legal, audit and other professional fees related to becoming a public company.

Research and development expenses were approximately $0.3$1.1 million for the sixthree months ended June 30, 2020March 31, 2022 and approximately $0.2$0.4 million for the sixthree months ended June 30, 2019.March 31, 2021. The $0.7 million increase in research and development expenses for the six months ended June 30, 2020 as compared to the prior period was primarily attributable to costs incurred in connection with our research activities and include costs associated with clinical trials, consultants, clinical trial materials, regulatory filings, facilities, laboratory expenses and other supplies.

Of the approximately $269,947$1.1 million in research and development expenses incurred during the sixthree months ended June 30, 2020, approximately $31,850March 31, 2022, $1.0 million was associated with activities related to the HAT indication, and approximately $238,097$0.1 million was associated with activities related to the ASD indication. These activities included, but were not limited to, milestone payments in connection with the ongoingrecently completed ASD trial.

Of the approximately $215,357$0.4 million in research and development expenses incurred during the sixthree months ended June 30, 2019,March 31, 2021, approximately $19,013$0.3 million was associated with activities related to the HAT indication, and approximately $196,344 was associated with activities related to the ASD indication. These activities include, but are not limited to, milestone payments in connection with the ongoing ASD trial.