Abivax SA provided an update on its clinical development strategy of lead compound ABX464 in UC and releases complementary data supporting the recently announced positive phase 2b top-line results. According to the latest additional analysis, the results after 16 weeks of once-daily oral treatment with ABX464 confirm and further extend the data with respect to the efficacy and the good safety profile already observed after 8-weeks of induction treatment. Complementary data analysis of the ABX464 phase 2b induction clinical trial in UC: In May 2021, the company announced the top-line data of its ABX464 randomized, placebo-controlled phase 2b trial in UC after the 8-week induction treatment, which demonstrated significant clinical efficacy in the overall patient population, as well as in patients previously refractory to biologics and/or JAK inhibitors, on primary and key secondary endpoints and a good safety profile of ABX464. The baseline disease characteristics were well balanced across all ABX464 dose groups and the placebo group. Enrolled patients suffered from longstanding UC with an overall median duration of 5.45 years. At inclusion, 71.4% of the patients showed a severe disease profile, with a baseline modified Mayo Score of 7 to 9 points. About 50% of the patients in each ABX464 treatment group and placebo were previously refractory to biologic treatments and/or JAK inhibitors. The majority of the patients was treated with concomitant UC medication at a stable dose (52% corticosteroids, 76.6% 5-ASA and 13.9% immunosuppressants). At week 8, 35%, 40%, 44% of patients treated with 25mg, 50mg, 100mg respectively achieved endoscopic improvement compared to 14% in the placebo group. As per the clinical study protocol, only patients without an endoscopic improvement at week 8, had another endoscopy performed at week 16. This criterion was chosen for ethical reasons to not require an additional endoscopy for patients who already had an endoscopic improvement at week 8. Among the patients, who had another endoscopy at week 16, higher percentages of clinical remission were achieved at week 16 in the ABX464 treatments groups (25mg, 50mg and 100mg) with 15%, 20% and 23% respectively and 13% in the placebo group. These results confirm the potency of ABX464 to maintain and to further improve clinical remission rates over time. Similar trends were observed for reduction of the modified Mayo Score, presence of clinical response, and endoscopic improvement as well as reduction in fecal calprotectin in patients treated with ABX464 both in the entire population as well as in the subset of patients who were previously exposed refractory to biologic treatments and/or JAK inhibitors. New clinical data on the phase 2a maintenance study in UC: Separately, on September 14, 2021, the company reports for the first time the 3-year efficacy data from its ongoing phase 2a maintenance study in UC. 15 out of the 22 patients who were initially enrolled into the phase 2a maintenance study in 2018, completed the third year of treatment with once-daily oral 50mg ABX464. Among the 13 patients who underwent centrally read endoscopies at the completion of year 3, 11 patients (85%) were still in clinical remission, among which 7 patients (54%) had an endoscopic remission (endoscopic subscore=0) and 11 patients had an endoscopic improvement (endoscopic subscore=0 or 1). The long-term safety profile of chronic ABX464 administration continues to be very favorable.