ABIVAX (ABVX) Study result summary

Study design and patient population

• Phase III ABTECT maintenance trial enrolled 580 adults with moderately to severely active ulcerative colitis who responded to induction therapy and were re-randomized to 25 mg, 50 mg obefazimod, or placebo for 44 weeks in a global, multicenter, randomized, double-blind, placebo-controlled design.

• Baseline characteristics were well balanced, with the 50 mg group having a higher rate of prior advanced therapy failure.

• Completion rates at 44 weeks were 78.8% for 25 mg, 82.1% for 50 mg, and 34.3% for placebo.

• The trial reported a historically low placebo remission rate of 10.4%, the lowest in Phase 3 UC maintenance re-randomization trials.

Efficacy results

• Both 25 mg and 50 mg doses met the primary endpoint, with clinical remission rates of 50.8% (25 mg), 51.3% (50 mg), and 10.4% for placebo at week 44.

• Placebo-adjusted clinical remission rates were 39.3% (25 mg) and 40.3% (50 mg), among the highest reported in maintenance studies (p < 0.0001).

• Both doses achieved highly significant results on all key secondary endpoints, including endoscopic improvement, endoscopic remission, HEMI, corticosteroid-free remission, and sustained remission.

• Placebo-adjusted endoscopic remission rates were 38% (50 mg) and 31% (25 mg), outperforming other therapies.

• Placebo-adjusted rates for key secondary endpoints ranged from 31.4% to 52.8%, all with p < 0.0001.

Safety profile

• Obefazimod demonstrated a favorable safety profile with no new safety signals over 44 weeks.

• Any treatment-emergent adverse event (TEAE): 25 mg (58.0%), 50 mg (71.8%), placebo (50.0%).

• Serious TEAEs were low: 25 mg (2.6%), 50 mg (5.6%), placebo (4.2%); serious adverse events and infections were low and similar across groups.

• No deaths reported; malignancies and non-melanoma skin cancers were rare, non-clustered, and mostly unrelated to treatment.

• Headaches were mild, mostly associated with induction, and did not lead to discontinuation.