Abivax SA (Abivax (ABVX)) had a good Monday. The company shared additional Phase 3 maintenance data for its investigational ulcerative colitis therapy obefazimod, and the stock responded by jumping nearly 36% in premarket trading Tuesday. At $130.57, investors were clearly excited about what the data showed.

The results, from the ABTECT Maintenance Part 2 trial, focused on two groups of patients: those who didn't respond to initial induction therapy and those who relapsed during maintenance. The key takeaway? Even if obefazimod doesn't work right away, it might still be worth sticking with.

Patients Who Failed Induction Still Benefited

For patients who didn't achieve a clinical response after eight weeks of induction treatment, continuing on obefazimod proved worthwhile. By Week 44, those on the 50 mg dose saw a 37.2% clinical remission rate, a 61.5% clinical response rate, and a 48.0% rate of endoscopic improvement. Histologic-endoscopic mucosal improvement hit 44.6%, and endoscopic remission reached 34.5%. These are solid numbers for a group that started as non-responders.

The message from Abivax is clear: some patients just need more time. The data suggest that extended treatment can unlock benefits even when the early signs aren't there.

Re-Treatment Restored Control After Relapse

The company also reported on patients who initially responded to obefazimod during induction but then relapsed after switching to placebo in Maintenance Part 1. When these patients were put back on open-label 50 mg obefazimod, 69.7% achieved a clinical response and 45.0% hit remission. Similarly, patients who relapsed on the 25 mg dose and were escalated to 50 mg posted response and remission rates of 66.7% and 45.5%, respectively.

Abivax sees this as evidence that obefazimod can regain disease control after a relapse, offering flexibility in long-term maintenance treatment. It's a nice insurance policy for patients who might wobble along the way.

Safety Data Supports FDA Submission

Safety-wise, the expanded dataset looked clean. The overall safety profile in Maintenance Part 2 was consistent with earlier studies, with no new signals. There were four non-melanoma skin cancer events reported—two in each dose group—but all occurred in patients with established risk factors. Two additional non-skin cancer malignancies in the 50 mg arm were deemed unrelated to the drug by investigators.

Abivax says this data strengthens the integrated clinical package for its planned New Drug Application to the FDA. The company remains on track to submit in the fourth quarter of 2026. Looking further ahead, topline results from a Phase 2b trial in Crohn's disease are expected by mid-2027.

For now, the market is betting that obefazimod has a real shot at becoming a new option for ulcerative colitis patients—even those who don't respond right away.