Acer Therapeutics Announces Full Enrollment of Pivotal Bioequivalence Trial of ACER-001 for Urea Cycle Disorders

Topline trial results expected in Q1 2021; targeting a pre-NDA meeting with FDA in Q2 2021

NEWTON, Mass., Dec. 22, 2020 (GLOBE NEWSWIRE) — Acer Therapeutics Inc. (Nasdaq: 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, today announced full enrollment of its pivotal trial evaluating the bioequivalence (BE) of ACER-001 compared to BUPHENYL^® (sodium phenylbutyrate). Acer is developing ACER-001 for the treatment of urea cycle disorders (UCDs).

The single-center, single-blind, randomized, single-dose crossover trial is designed to demonstrate the BE of ACER-001 compared to BUPHENYL^® under fed conditions, in approximately 36 healthy adults. Results of the trial are expected in the first quarter of 2021.

“We completed the first bridging study in the first quarter of 2020, the results of which demonstrated bioequivalence to BUPHENYL^® under fasted conditions, but we also confirmed a significant food effect with sodium phenylbutyrate,”¹ said Chris Schelling, CEO and Founder of Acer. “After meeting with the FDA in the third quarter of this year to discuss the development plan, it was determined that in light of the food effect a second BE study conducted under fed conditions would be needed to bridge to BUPHENYL^® under a 505(b)(2) application. This was a challenging request in the face of COVID-19, and I am pleased to say that our partners at PPD, the global contract research organization, did an incredible job getting this trial fully enrolled before the end of the year.”

Upon successful completion of ongoing development activities, Acer intends to submit a request to the U.S. Food and Drug Administration (FDA) in the first quarter of 2021 for a pre-NDA meeting on ACER-001.

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.^2,3

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 can 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 a taste-masked, immediate-release proprietary powder formulation for oral administration of sodium phenylbutyrate (NaPB) via suspension. ACER-001 is being developed using a microencapsulation process for the treatment of various inborn errors of metabolism, including UCDs and Maple Syrup Urine Disease (MSUD). ACER-001 microparticles consist of a core center, a layer of active drug, and a taste-masking coating that quickly dissolves in the stomach, allowing taste to be neutralized while still allowing for rapid systemic release. We believe that if ACER-001 is approved, its taste-masked properties will make it a compelling alternative to existing NaPB-based treatments, as the unpleasant taste associated with NaPB is cited as a major impediment to patient compliance with those treatments.⁴ 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 will receive FDA approval or become commercially available for the uses being investigated.

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 (a taste-masked, immediate release formulation of sodium phenylbutyrate) for the treatment of various inborn errors of metabolism, including urea cycle disorders (UCDs) and Maple Syrup Urine Disease (MSUD); emetine hydrochloride, a host-directed therapy against a variety of infectious diseases, initially for the treatment of patients with COVID-19; EDSIVO™ (celiprolol) for the treatment of vascular Ehlers-Danlos syndrome (vEDS) in patients with a confirmed type III collagen (COL3A1) mutation; and osanetant for the treatment of induced Vasomotor Symptoms (iVMS). 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. For more information, visit www.acertx.com.

References

1. Nakano S, et al. Effect of food on the pharmacokinetics and therapeutic efficacy of 4-phenylbutyrate in progressive familial intrahepatic cholestasis. Sci Rep 9, 17075 (2019).
2. Ah Mew N, et al. Urea cycle disorders overview. Gene Reviews. Seattle, Washington: University of Washington, Seattle; 1993.
3. Häberle J, et al. Suggested guidelines for the diagnosis and management of urea cycle disorders. Orphanet Journal of Rare Diseases. 2012;7(32).
4. 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.

Forward-Looking Statements
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Investor Contact:
Hans Vitzthum
LifeSci Advisors
Ph: 617-430-7578
hans@lifesciadvisors.com

Jim DeNike
Acer Therapeutics Inc.
Ph: 844-902-6100
jdenike@acertx.com