ABIVAX (ABVX) investor relations material

Study design and patient population

• Part 2 of the ABTECT maintenance study included highly refractory ulcerative colitis patients, focusing on induction non-responders and Part 1 relapsers, all treated with obefazimod, primarily at 50 mg.

• 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.

• No placebo arm was included in Part 2; all patients received active treatment.

• Baseline disease activity was higher in Part 2 than in Part 1, with more severe inflammation and higher Mayo scores.

• Part 2 served as a supplemental dataset, expanding the cumulative safety and efficacy data for obefazimod and allowing 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 in induction non-responders were as high or higher than those seen in induction responders for other approved therapies.

• Efficacy was consistent across symptomatic and objective endpoints, supporting benefit in initial non-responders.

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.

• Malignancy and NMSC rates were consistent with expected UC background rates, with all NMSC cases in Part 2 occurring in patients with established risk factors.

• No new or unexpected safety patterns emerged; serious infections and cardiac events were infrequent and not dose-related.

• Enhanced skin lesion surveillance increased detection but did not show an imbalance in overall skin lesion rates between treatment groups.

• Exposure-adjusted incidence rates for malignancies and NMSCs were within or below published UC reference ranges.