Study of Epetraborole in Patients With Treatment-refractory MAC Lung Disease

In the Phase 2 part of the study, approximately 80 patients will be randomized in a 1:1 ratio (40 patients receiving active epetraborole tablets and 40 patients receiving matching placebo tablets). The Phase 2 part of the study includes a blinded psychometric analysis plan to assess the psychometric properties of a novel PRO instrument. In addition, symptom-based clinical responses will be assessed using blinded data, to inform the measurement of clinical response in the Phase 3 part of the study. The Phase 3 part of the study will test the superiority of epetraborole + OBR compared to placebo + OBR. In this part of the study, approximately 234 patients are planned to be randomized in a 2:1 ratio (156 patients receiving active epetraborole tablets and 78 patients receiving matching placebo tablets). The current symptom-based clinical response definition (using the novel PRO) in Phase 3 is a placeholder to be verified after Phase 2 analyses based on data through Month 6. In addition, the Sponsor will determine if the sample size for Phase 3 should be adjusted and will verify the Phase 3 epetraborole dosage regimen based on the observed plasma epetraborole exposure. Phase 3 data analyses will include a review of patient-reported outcomes, microbiological, safety, and PK data collected at multiple time points through Month 6. Patients in Phase 3 will continue double-blinded study drug for 12 months after the first negative MAC culture that defines sputum culture conversion; study drug will be discontinued in patients who remain MAC culture positive despite 6 months of therapy with study drug.