AN2 Therapeutics has initiated the Phase III part of its Phase II/III clinical trial of epetraborole for treatment-refractory mycobacterium avium complex (MAC) lung disease.

The latest move comes after the completion of the enrolment of 80 patients in the Phase II part.

The study compared the pharmacokinetics, safety, and efficacy of oral epetraborole plus an optimised background regimen (OBR) against placebo plus an OBR.

It also assessed clinical response using several patient-reported outcome tools.

The Phase II study data will be used to inform the clinical response measures to be assessed in the Phase III part, as well as to confirm the final sample size.

The key goal of the Phase III study is to determine whether epetraborole plus an OBR is superior to placebo plus an OBR. A total of 234 patients are enrolled in this study.

AN2 Therapeutics co-founder, president and CEO Eric Easom said: “Given epetraborole’s novel mechanism of action, encouraging clinical and non-clinical data to date, and convenient once-daily oral dosing, we believe that if approved, epetraborole has the potential to become the backbone of therapy for patients suffering with often debilitating treatment-refractory MAC lung disease.

“We look forward to sharing topline results from the Phase II portion of the trial in summer 2024, at which time we expect to be well on our way to completing Phase III enrolment.

“We will provide more information on the projected Phase III enrolment timeline as we get closer to the Phase II topline readout.”

The company plans to use epetraborole study results to submit regulatory filings and seek approval in the US and Japan.

Epetraborole previously received qualified infectious disease products and fast-track designations from the US Food and Drug Administration (FDA) for treatment-refractory MAC lung disease.

The regulator also granted orphan drug designation for the treatment of infections caused by nontuberculous mycobacteria.