Will novel antibiotic become front-line for C. difficile?

Due to observed clinical success, Acurx Pharmaceuticals, Inc. has discontinued the Phase IIb clinical trial of its lead antibiotic candidate, ibezapolstat, for Clostridioides difficile infection (CDI). In the trial, ibezapolstat and the control antibiotic vancomycin, a standard treatment for C. difficile infection, delivered high rates of clinical cure without any emerging safety concerns. 

Therefore, based on observed aggregate blinded data and other factors, the trial will cease. The company anticipated this will allow it to advance ibezapolstat, a first-in-class antibiotic product candidate to Phase III trials sooner. 

Ibezapolstat Phase II trial

The completed Phase IIa study was followed by a Phase IIb segment in the US, which together comprise the Phase II clinical trial.

In the finished Phase IIa segment of this trial, 10 patients with diarrhoea caused by C. difficile were given ibezapolstat 450mg orally, twice per day for a total of 10 days.

Every patient was investigated for recurrence for 28± 2 days. Per protocol, once 10 of the projected 20 Phase IIa patients completed treatment, resulting in a 100 percent cured infection at the treatment end, the clinical trial was terminated early.

Phase IIa data demonstrated complete eradication of colonic C. difficile by day three of treatment with ibezapolstat in addition to an observed overgrowth of healthy gut microbiota during and after therapy.

Significantly, emerging data showed an increased concentration of secondary bile acids during and following ibezapolstat therapy. This is known to correlate with colonisation resistance against C. difficile. Lower primary bile acids and the favourable increase in the ratio of secondary-to-primary bile acids suggest that ibezapolstat may reduce the likelihood of CDI recurrence when compared to vancomycin, according to Acurx Pharmaceuticals.

Developing a front-line C. difficile infection treatment

Acurx Pharmaceuticals is looking forward to “reporting the full ibezapolstat data which will include the most extensive data for any antibiotic on sustained clinical cure to date in patients with CDI, as well as a comparison of the effect on the microbiome between oral ibezapolstat and oral vancomycin. We believe that, if approved by the US Food and Drug Administration (FDA) for marketing, these attributes will support the use of ibezapolstat for front-line treatment of CDI,” declared David Luci, the company’s President and Chief Executive Officer.