ChemoCentryx’s (NASDAQ:CCXI) Phase III avacopan (CCX168) for anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis divides experts on whether payers would push back on first-line (1L) use without demonstrating superior efficacy versus corticosteroids. Nonetheless, they agreed optimism is warranted for the Phase III to prove noninferiority on the 26-week remission coprimary endpoint.
One analyst report ascribed the Phase III ADVOCATE study (NCT02994927) a 65% probability of success, and a second noted expectations that the trial would meet its primary endpoints to show noninferiority. However, two interviewed experts said they were uncertain about the 52-week coprimary endpoint assessing clinically relevant sustained remission using the Birmingham Vasculitis Score (BVAS). Since relapses can occur after two to three years, 52 weeks may be too short, they noted.
The trial’s other coprimary endpoint is BVAS at 26 weeks, and experts were more optimistic based on Phase II 12-week BVAS results. Noninferiority would be clinically significant given its improved safety profile. However, some experts were cautious due to the unpredictability of extrapolating data based on fewer patients to a larger Phase III trial.