Acer Therapeutics Plans NDA Submission for ACER-001 in Q3 2021 Following Pre-NDA Meeting with FDA

NEWTON, Mass. and GENEVA, Switzerland, May 25, 2021 (GLOBE NEWSWIRE) — Acer Therapeutics Inc. (Nasdaq: ACER)(“Acer”), a pharmaceutical company focused on the acquisition, development and commercialization of therapies for serious rare and life-threatening diseases with significant unmet medical needs, and RELIEF THERAPEUTICS Holding AG (SIX: RLF, OTCQB: RLFTF)(“Relief”), a biopharmaceutical company with its lead compound RLF-100^TM (aviptadil) in advanced clinical development to treat severe COVID-19 patients, today announced the outcome of Acer’s pre-New Drug Application (NDA) meeting with the U.S. Food and Drug Administration (FDA) for ACER-001 for the treatment of Urea Cycle Disorders (UCDs). ACER-001 is a proprietary immediate release multi-particulate powder formulation of sodium phenylbutyrate (NaPB) with a taste-masked coating. ACER-001 is being developed in collaboration with Relief.

The purpose of the pre-NDA meeting was to discuss the content of Acer’s planned NDA submission. Based on FDA feedback, the Companies believe the proposed data package will be sufficient to support an NDA submission under the Section 505(b)(2) regulatory pathway of ACER-001 for the treatment of patients with UCDs. Following NDA submission and FDA determination of acceptance for filing, the FDA will conduct a substantive review before deciding upon the action on the application.

“We are pleased with the outcome of our recent pre-NDA meeting with FDA, supporting our belief that the studies and data we intend to include in our planned NDA for ACER-001 should be sufficient for NDA submission,” said Chris Schelling, CEO and Founder of Acer. “We remain on track to complete the NDA submission in Q3 2021, provided that we obtain agreement with the FDA on our initial pediatric study plan (iPSP).”

Jack Weinstein, CFO and Treasurer of Relief Therapeutics, added: “The outcome of the pre-NDA meeting with the FDA is highly encouraging and marks an important milestone in support of the development and potential commercialization of ACER-001 worldwide. We are pleased with the progress of the ACER-001 program and look forward to working with the Acer team to potentially bring to market an alternative to existing NaPB-based treatments.”

ACER-001 is an investigational product candidate which has not been approved by FDA. There can be no assurance that if submitted, an NDA will be accepted for filing and substantive review or, if filed, that an NDA would be approved.

About UCDs
UCDs are a group of disorders caused by genetic mutations that result in a deficiency in one of the six enzymes that catalyze the urea cycle, which can lead to an excess accumulation of ammonia in the bloodstream, a condition known as hyperammonemia. Acute hyperammonemia can cause lethargy, somnolence, coma, and multi-organ failure, while chronic hyperammonemia can lead to headaches, confusion, lethargy, failure to thrive, behavioral changes, and learning and cognitive deficits. Common symptoms of both acute and chronic hyperammonemia also include seizures and psychiatric symptoms.^1,2 The current treatment of UCDs consists of dietary management to limit ammonia production in conjunction with medications that provide alternative pathways for the removal of ammonia from the bloodstream. Some patients may also require individual branched-chain amino acid supplementation.

Current medical treatments for UCDs include nitrogen scavengers, RAVICTI® and BUPHENYL®, in which the active pharmaceutical ingredients are glycerol phenylbutyrate (GPB) and sodium phenylbutyrate (NaPB), respectively. According to a 2016 study by Shchelochkov et al., published in Molecular Genetics and Metabolism Reports, while nitrogen scavenging medications have been shown to be effective in helping to manage ammonia levels in some patients with UCDs, non-compliance with treatment is common. Reasons referenced for non-compliance associated with some available medications include unpleasant taste, the frequency with which medication must be taken, the number of pills, and the high cost of the medication.³

About ACER-001
ACER-001 is being developed for the treatment of various inborn errors of metabolism, including UCDs and MSUD. ACER-001 is a proprietary immediate release powder formulation of sodium phenylbutyrate (NaPB). The formulation is a multi-particulate dosage formulation for oral administration consisting of a core center, a layer of active drug, and a taste-masked coating designed to avoid the bitter taste in the mouth while quickly dissolving in the low pH of the stomach. ACER-001’s taste-masked formulation is aimed to improve the palatability of NaPB. Acer has been granted orphan drug designation by the FDA for the MSUD indication. ACER-001 is under clinical investigation and its safety and efficacy have not been established. There is no guarantee that this product candidate will receive U.S. FDA approval or become commercially available for the indications under investigation.

About Acer Therapeutics Inc.
Acer is a pharmaceutical company focused on the acquisition, development and commercialization of therapies for serious rare and life-threatening diseases with significant unmet medical needs. Acer’s pipeline includes four programs: ACER-001 (sodium phenylbutyrate) for the treatment of various inborn errors of metabolism, including urea cycle disorders (UCDs) and Maple Syrup Urine Disease (MSUD); EDSIVO™ (celiprolol) for the treatment of vascular Ehlers-Danlos syndrome (vEDS) in patients with a confirmed type III collagen (COL3A1) mutation; ACER-801 (osanetant) for the treatment of induced Vasomotor Symptoms (iVMS); and ACER-2820 (emetine), a host-directed therapy against a variety of infectious diseases, including COVID-19. Each of Acer’s product candidates is believed to present a comparatively de-risked profile, having one or more of a favorable safety profile, clinical proof-of-concept data, mechanistic differentiation and/or accelerated paths for development through specific programs and procedures established by the FDA. In March 2021, Acer entered into a Collaboration and License Agreement with Relief Therapeutics for the worldwide development and commercialization of ACER-001. For more information, visit www.acertx.com.

About RELIEF THERAPEUTICS Holding AG
Relief focuses primarily on clinical-stage programs based on molecules with a history of clinical testing and use in human patients or a strong scientific rationale. Relief’s lead drug candidate RLF-100™ (aviptadil), a synthetic form of Vasoactive Intestinal Peptide (VIP), is in late-stage clinical testing in the U.S. for the treatment of respiratory deficiency due to COVID-19. As part of its pipeline diversification strategy, in March 2021, Relief entered into a Collaboration and License Agreement with Acer Therapeutics for the worldwide development and commercialization of ACER-001. ACER-001 is a taste-masked and immediate release proprietary powder formulation of sodium phenylbutyrate (NaPB) for the treatment of Urea Cycle Disorders and Maple Syrup Urine Disease.

RELIEF THERAPEUTICS Holding AG is listed on the SIX Swiss Exchange under the symbol RLF and quoted in the U.S. on OTCQB under the symbol RLFTF. For more information, visit
www.relieftherapeutics.com. Follow Relief on LinkedIn.

References

1. Ah Mew N, et al. Urea cycle disorders overview. Gene Reviews. Seattle, Washington: University of Washington, Seattle; 1993.
2. Häberle J, et al. Suggested guidelines for the diagnosis and management of urea cycle disorders. Orphanet Journal of Rare Diseases. 2012;7(32).
3. Shchelochkov OA, et al. Barriers to drug adherence in the treatment of urea cycle disorders: Assessment of patient, caregiver and provider perspectives. Mol Genet Metab. 2016;8:43-47.

Acer Forward-Looking Statements
This press release contains “forward-looking statements” that involve substantial risks and uncertainties for purposes of the safe harbor provided by the Private Securities Litigation Reform Act of 1995. All statements, other than statements of historical facts, included in this press release regarding strategy, future operations, timelines, future financial position, future revenues, projected expenses, regulatory submissions, actions or approvals, cash position, liquidity, prospects, plans and objectives of management are forward-looking statements. Examples of such statements include, but are not limited to, statements relating to the potential for our product candidates to safely and effectively treat diseases and to be approved for marketing; the commercial or market opportunity of any of our product candidates in any target indication and any territory; our ability to secure the additional capital necessary to fund our various product candidate development programs; the adequacy of our capital to support our future operations and our ability to successfully fund, initiate and complete clinical trials and regulatory submissions; the ability to protect our intellectual property rights; our strategy and business focus; and the development, expected timeline and commercial potential of any of our product candidates. We may not actually achieve the plans, carry out the intentions or meet the expectations or projections disclosed in the forward-looking statements and you should not place undue reliance on these forward-looking statements. Such statements are based on management’s current expectations and involve risks and uncertainties. Actual results and performance could differ materially from those projected in the forward-looking statements as a result of many factors, including, without limitation, risks and uncertainties associated with the ability to project future cash utilization and reserves needed for contingent future liabilities and business operations, the availability of sufficient resources to fund our various product candidate development programs and to meet our business objectives and operational requirements, the fact that the results of earlier studies and trials may not be predictive of future clinical trial results, the protection and market exclusivity provided by our intellectual property, the substantial costs and diversion of management’s attention and resources which could result from pending securities litigation, risks related to the drug development and the regulatory approval process, including the timing and requirements of regulatory actions, and the impact of competitive products and technological changes. We disclaim any intent or obligation to update these forward-looking statements to reflect events or circumstances that exist after the date on which they were made. You should review additional disclosures we make in our filings with the Securities and Exchange Commission, including our Quarterly Reports on Form 10-Q and our Annual Report on Form 10-K. You may access these documents for no charge at http://www.sec.gov.

Relief Forward-Looking Statements
This communication expressly or implicitly contains certain forward-looking statements concerning RELIEF THERAPEUTICS Holding AG and its businesses. The results reported herein may or may not be indicative of the results of future and larger clinical trials for ACER-001 for the treatment of UCDs and MSUD, nor whether the ongoing clinical trials of Relief’s lead compound, RLF-100™ (aviptadil) in advanced clinical development to treat respiratory deficiency due to COVID-19, will be successful. Such statements involve certain known and unknown risks, uncertainties and other factors, which could cause the actual results, financial condition, performance or achievements of RELIEF THERAPEUTICS Holding AG to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. RELIEF THERAPEUTICS Holding AG is providing this communication as of this date and does not undertake to update any forward-looking statements contained herein as a result of new information, future events or otherwise.

CORPORATE CONTACTS
Acer Therapeutics:
Jim DeNike
Acer Therapeutics Inc.
+1 844-902-6100
jdenike@acertx.com

RELIEF THERAPEUTICS Holding AG:
Jack Weinstein
Chief Financial Officer and Treasurer
contact@relieftherapeutics.com

MEDIA CONTACTS
Relief (Europe):
Anne Hennecke
MC Services AG
relief@mc-services.eu
+49 (0) 211-529-252-22

INVESTOR RELATIONS CONTACTS
Acer Therapeutics:
Hans Vitzthum
LifeSci Advisors
+1 617-430-7578
hans@lifesciadvisors.com

Relief (Europe):
Anne Hennecke
MC Services AG
relief@mc-services.eu
+49 (0) 211-529-252-22