Acurx Pharmaceuticals, Inc. announced that results from the ibezapolstat (IBZ) Phase 2 clinical trial in patients with C. difficile Infection (CDI) were presented at the 17th Biennial Congress of the Anaerobe Society of the Americas on July 11th which was held at the University of Michigan, Ann Arbor, from July 8 to 11, 2024. Taryn A. Eubank, PharmD, BCIDP, Research Assistant Professor, University of Houston College of Pharmacy delivered an oral presentation entitled: Clinical Efficacy of Ibezapolstat in CDI: Results from Phase 2 trials. Acurx has previously announced that it had a successful FDA End-of-Phase 2 Meeting and Phase 3 Readiness for ibezapolstat for the Treatment of C. difficile Infection.

Agreement with FDA was reached on key elements to move forward with its international Phase 3 clinical trial program. Agreement was also reached with FDA on the complete non-clinical and clinical development plan for filing of a New Drug Application (NDA) for marketing approval. Planning continues to advance ibezapolstat into international Phase 3 clinical trials for treatment of C. difficile Infection (CDI).

Acurx is also now preparing to submit requests for guidance to initiate clinical trials in the European Union, the United Kingdom, Japan and Canada. About the Anaerobe Society of the Americas: Founded in 1992, The Anaerobe Society of the Americas is an international organization, promoting the study and application of knowledge of anaerobic bacteriology. The primary activity of the society is organizing the biennial Anaerobe Congress for researchers, clinicians, and laboratory scientists from around the world to engage in presentations, exchanges, and dialogues related to anaerobes.

The completed multicenter, open-label single-arm segment (Phase 2a) study was followed by a double-blind, randomized, active-controlled, non-inferiority, segment (Phase 2b) at 28 US clinical trial sites which together comprise the Phase 2 clinical trial. This Phase 2 clinical trial was designed to evaluate the clinical efficacy of ibezapolstat in the treatment of CDI including pharmacokinetics and microbiome changes from baseline and continue to test for anti-recurrence microbiome properties seen in the Phase 2a trial, including the treatment-related changes in alpha diversity and bacterial abundance and effects on bile acid metabolism. Key elements for the two Phase 3, non-inferiority, pivotal trials were confirmed and included agreement on the protocol design, patient population, primary and secondary endpoints, and size of the registration safety database.

Based on FDA recommendations, and in anticipation of an EMA Scientific Advice Meeting, the primary efficacy analysis will be performed using a Modified Intent-To-Treat (mITT) population consistent with EMA requirements. This will result in an estimated 450 subjects in the mITT population, randomized in a 1:1 ratio to either ibezapolstat or standard-of-care vancomycin, enrolled into the initial Phase 3 trial. The trial design not only allows determination of ibezapolstat's ability to achieve Clinical Cure of CDI as measured 2 days after 10 days of oral treatment, but also includes assessment of ibezapolstat's potential effect on reduction of CDI recurrence in the target population.

In the event non-inferiority of ibezapolstat to vancomycin is demonstrated, further analysis will be conducted to test for superiority. The completed Phase 2a segment of this trial was an open label cohort of up to 20 subjects from study centers in the United States. In this cohort, 10 patients with diarrhea caused by C. difficile were treated with ibezapolstat 450 mg orally, twice daily for 10 days.

All patients were followed for recurrence for 28± 2 days. Per protocol, after 10 patients of the projected 20 Phase 2a patients completed treatment (100% cured infection at End of Treatment), the Trial Oversight Committee assessed the safety and tolerability and made its recommendation regarding early termination of the Phase 2a study and advancement to the Ph2b segment. The Company's Scientific Advisory Board concurred with this recommendation.

In the now completed Phase 2b trial segment, 32 patients with CDI were enrolled and randomized in a 1:1 ratio to either ibezapolstat 450 mg every 12 hours or vancomycin 125 mg orally every 6 hours, in each case, for 10 days and followed for 28 ± 2 days following the end of treatment for recurrence of CDI. The two treatments were identical in appearance, dosing times, and number of capsules administered to maintain the blind. Ibezapolstat was well-tolerated, with three patients each experiencing one mild adverse event assessed by the blinded investigator to be drug-related.

All three events were gastrointestinal in nature and resolved without treatment. There were no drug-related treatment withdrawals or no drug-related serious adverse events, or other safety findings of concern. In the Phase 2b vancomycin control arm, 14 out of 14 patients experienced Clinical Cure.

The Phase 2b clinical trial segment was discontinued due to success. The Company made this decision in consultation with its medical and scientific advisors and statisticians based on observed aggregate blinded data and other factors, including the cost to maintain clinical trial sites and slow enrollment due to COVID-19 and its aftermath. The Company had determined that the trial performed as anticipated for both treatments, ibezapolstat and the control antibiotic vancomycin (a standard of care to treat patients with CDI), with high rates of clinical cure observed across the trial.

The Phase 2b trial was originally designed to be a non-inferiority (NI) trial and later amended to include an interim efficacy analysis with review by an Independent Data Monitoring Committee (IDMC). The decision to end the trial early based on blinded clinical observations obviated the need for an interim analysis, IDMC review, and NI assessment. The Company determined, in consultation with its clinical and statistical experts, that presenting clinical cure rates for the primary efficacy endpoint is the most appropriate representation for the clinical activity of ibezapolstat in treating CDI.

In the Phase 2 clinical trial, the Company will also evaluate pharmacokinetics (PK) and microbiome changes and test for anti-recurrence microbiome properties, including the change from baseline in alpha diversity and bacterial abundance, especially overgrowth of healthy gut microbiota Actinobacteria and Firmicute phylum species during and after therapy. Phase 2a data demonstrated complete eradication of colonic C. difficile by day three of treatment with ibezapolstat as well as the observed overgrowth of healthy gut microbiota, Actinobacteria and Firmicute phyla species, during and after therapy.