French firm Abivax SA (Euronext Paris: ABVX / Nasdaq: ABVX) reported that obefazimod, its oral once-daily miR-124 enhancer, met the primary endpoint and all key secondary endpoints in the Phase III ABTECT maintenance trial in moderately to severely active ulcerative colitis, positioning the drug as a potential first-in-class oral option ahead of a planned FDA submission later this year. While the overall safety profile was consistent with previous studies, the company reported several cases of non-melanoma skin cancer in the 50 mg arm, primarily among older patients, though no deaths, cardiac fibrosis signals, or new major safety concerns were observed.
The ABTECT maintenance trial is a global, 44-week, randomized, double-blind, placebo-controlled study that re-randomized induction responders from the ABTECT-1 and ABTECT-2 trials (N=580) to obefazimod 25 mg, 50 mg, or placebo once daily. At Week 44, clinical remission rates were 50.8% and 51.3% for the 25 mg and 50 mg doses, respectively, versus 10.4% for placebo, yielding placebo-adjusted differences of at least 39.3% and 40.3% (both p < 0.0001). Abivax noted that the placebo remission rate was the lowest reported to date in a Phase III UC maintenance responder re-randomization trial, potentially magnifying the apparent treatment effect compared with studies reporting higher placebo rates.
Both doses also met secondary endpoints including endoscopic improvement, endoscopic remission, histologic-endoscopic mucosal improvement, corticosteroid-free remission, and sustained remission. Serious infection rates remained below 1.5% across active treatment arms. Six malignancies were reported during the study, including three non-NMSC cases (prostate cancer, breast cancer, and colonic dysplasia) and three NMSC cases. Abivax said investigators considered the non-NMSC cases unrelated to treatment and noted no organ-specific clustering. For the NMSC cases, two of the four patients affected in the 50 mg arm were deemed not or unlikely related to treatment, while one of the remaining cases occurred in a patient with a prior history of skin cancer. The company also noted that the mean age of patients with NMSC was 62 years, compared with 42 years in the overall study population, consistent with the increased age-related risk of skin cancer.