The EBO-301 study is being discontinued following topline results from the phase 2 part of the study in treatment-refractory patients with MAC lung disease.
RT’s Three Key Takeaways:
- Trial Termination Due to Insufficient Efficacy: AN2 Therapeutics has decided to terminate its phase 2/3 EBO-301 trial evaluating epetraborole for treatment-refractory MAC lung disease after topline results indicated that the treatment did not demonstrate sufficient efficacy, particularly in sputum culture conversion at six months.
- Primary Objective Met: Despite the trial’s discontinuation, the phase 2 part of the study did achieve its primary objective by demonstrating the potential validation of a novel patient-reported outcome tool and showing a higher patient-reported outcome-based clinical response rate in the epetraborole arm compared to placebo, though the difference was not statistically significant.
- Boron Chemistry Platform: With the trial’s termination, AN2 Therapeutics plans to refocus its efforts on its boron chemistry platform, which shows promise in addressing unmet needs in infectious diseases and oncology, while also evaluating the future potential of epetraborole in other patient populations.
AN2 Therapeutics has announced the termination of its phase 2/3 trial evaluating epetraborole on top of an optimized background regimen for treatment-refractory mycobacterium avium complex (MAC) lung disease after topline results showed insufficient efficacy.
The phase 2 part of the study met its primary objective of demonstrating the potential validation of a novel patient-reported outcome tool and a higher patient-reported outcome-based clinical response rate in the epetraborole plus optimized background regimen arm (39.5%) versus placebo plus optimized background regimen (25%; treatment difference 13.9%, p=0.19).
However, sputum culture conversion at month six, a key secondary endpoint, was similar between treatment arms (13.2% in epetraborole plus optimized background regimen versus 10% placebo plus optimized background regimen; treatment difference 3.4%, p=0.64).
Trial Stopped Due to Efficacy Concerns
In February, the company voluntarily paused new patient enrollment in the phase 3 part of the study due to potentially lower-than-expected efficacy observed in blinded aggregate data.
Based on the latest topline data, the company will terminate the phase 2 (80 patients) and phase 3 parts of the EBO-301 trial (97 patients enrolled prior to pause). Oral epetraborole 500 mg daily was generally well-tolerated, and the study was not terminated due to safety concerns.
“These results are deeply disappointing as there is a high unmet need for new therapies in treatment-refractory MAC lung disease,” says Eric Easom, co-founder, chairman, president, and CEO of AN2 Therapeutics, in a release. “We sincerely thank the patients, investigators, study site staff and AN2 employees who were part of the journey to investigate the prospects of epetraborole in this very difficult-to-treat patient population.
Next Steps and Future Focus
“In the coming months, we will further evaluate the results from the EBO-301 study and make informed decisions regarding potential future development of epetraborole for NTM (nontuberculous mycobacteria) lung disease in other patient populations. In the near term, we plan to accelerate our R&D efforts on our boron chemistry platform where we believe we have several promising programs in infectious diseases and oncology.”
AN2’s core technology approach is based on the use of boron chemistry for its research and development initiatives. Boron has a distinctive ability to bind with biological targets through a reversible covalent bond and the potential to address biological targets that have been difficult to inhibit using traditional carbon-based molecules.
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