ABIVAX (ABVX) Study result summary

Study design and patient population

• ABTECT Maintenance Part 2 included highly refractory ulcerative colitis patients, focusing on induction non-responders and relapsers from Part 1, all receiving obefazimod without a placebo arm.

• Over 55% of Part 2 patients had failed at least one advanced therapy, with a high proportion of JAK inhibitor failures and higher baseline inflammatory burden than Part 1.

• Baseline disease activity was higher in Part 2, with elevated Mayo scores and fecal calprotectin levels compared to Part 1.

• Part 2 served as a supplemental dataset, expanding the cumulative safety and efficacy data for obefazimod.

• The study design allowed assessment of longer-term benefit in patients who would typically discontinue in other trials.

Efficacy results

• 37.2% of 50 mg induction non-responders achieved clinical remission and 34.5% achieved endoscopic remission at Week 44.

• Dose escalation from 25 mg to 50 mg restored disease control in 45.5% of relapsed patients, with clinical response rates up to 69.7%.

• Induction non-responders treated with 50 mg showed clinical response (61.5%), endoscopic improvement (48.0%), and HEMI (44.6%) at Week 44.

• Endoscopic remission rates matched or exceeded those seen with other approved therapies.

• Efficacy was durable and clinically meaningful in a highly refractory population, with high completion rates at 44 weeks.

Safety findings

• Over 1,700 patient-years of exposure were accumulated across phase II and III, with >100 patients treated for more than 5 years.

• Malignancies excluding non-melanoma skin cancers (NMSCs) were rare, with exposure-adjusted incidence rates consistent with published UC reference ranges.

• NMSCs were detected at rates similar to or below background, with all cases in patients with established risk factors and enhanced surveillance protocols in place.

• Serious adverse events, including infections and malignancies, were infrequent and comparable to placebo and other approved agents.

• No new or unexpected safety patterns emerged, and adverse events typical of broad immunosuppression remained low.