PARIS, June 30, 2026, 13:04 CEST
- Abivax shares were up 35.77% at 113.10 euros on Euronext Paris, the top SBF 120 move shown by MarketScreener at 0645 EDT.
- The market’s fresh read is in the patient-year math: all-active malignancy rates sat inside Abivax’s stated ulcerative colitis background range, though the 50 mg maintenance row remains the number to watch.
- Abivax still targets a fourth-quarter 2026 U.S. FDA filing for obefazimod in ulcerative colitis.
Abivax SA (EPA:ABVX; NASDAQ:ABVX) rose sharply in Paris on Tuesday after late Monday data gave investors a cleaner way to judge cancer risk in its ulcerative colitis drug programme. Euronext Paris was open for a regular session, with June 30 listed as a 0900-1730 CEST trading day.
The stock was last shown at 113.10 euros, up 35.77%, with a five-day gain of 32.05% and a year-to-date loss cut to 6.06%, MarketScreener data showed. U.S.-listed shares had jumped 26.4% in extended trading after the release, Reuters reported.
The trade is less about a new remission headline than about the denominator. Abivax’s expanded dataset now covers 1,704 patient-years of active drug exposure. In that larger pool, malignancies excluding non-melanoma skin cancer ran at 0.35 events per 100 patient-years for all active doses combined, within the company’s 0.30-0.70 expected ulcerative colitis background range.
| Safety rate, events per 100 patient-years | 50 mg | All active | Expected UC background |
|---|---|---|---|
| Part 2 only: malignancies excluding NMSC | 0.69 | 0.48 | 0.30-0.70 |
| Phase 3 maintenance, Part 1 + Part 2: malignancies excluding NMSC | 0.91 | 0.56 | 0.30-0.70 |
| Integrated Phase 2 + Phase 3: malignancies excluding NMSC | 0.64 | 0.35 | 0.30-0.70 |
| Part 2 only: NMSC | 0.69 | 0.95 | 0.70-1.40 |
| Integrated Phase 2 + Phase 3: NMSC | 0.64 | 0.59 | 0.70-1.40 |
That split is the part investors may miss. The all-active pool supports Abivax’s safety case. The 50 mg Phase 3 maintenance malignancy rate, at 0.91 per 100 patient-years, sits above the top of the company’s background band, even as the broader 50 mg integrated rate sits inside it.
The reason it matters is simple. Abivax shares sank after June 1 data, even though 50.8% of patients on 25 mg and 51.3% on 50 mg achieved clinical remission against 10.4% on placebo. Investors focused on cancer cases in the higher-dose arm; investigators considered those cases unrelated to treatment, Reuters reported at the time.
The new Part 2 efficacy readout also gave bulls more to use. Among induction non-responders kept on 50 mg obefazimod, 37.2% achieved clinical remission and 34.5% achieved endoscopic remission at Week 44. Among patients who relapsed on 25 mg in Part 1 and moved to 50 mg in Part 2, 45.5% regained clinical remission.
| New efficacy cut | Clinical remission | Clinical response | Endoscopic remission |
|---|---|---|---|
| Induction non-responders, 25 mg | 23.5% | 50.6% | 22.2% |
| Induction non-responders, 50 mg | 37.2% | 61.5% | 34.5% |
| Part 1 relapsers, placebo to 50 mg | 45.0% | 69.7% | 32.1% |
| Part 1 relapsers, 25 mg to 50 mg | 45.5% | 66.7% | 24.2% |
Chief Executive Marc de Garidel said the Part 2 results were “substantially expanding our long-term safety database.” Remo Panaccione, a professor of medicine and director of the IBD Clinic at the University of Calgary, said observed rates were “consistent with expected background rates.” Abivax
Broker reaction stayed positive. MarketScreener reported that Stifel kept a buy rating and 115-euro target, while Oddo BHF kept an outperform rating and 120-euro target. Oddo said the new analyses did not prove definitive absence of risk, but gave more reassurance than the first maintenance readout.
Competition is not static. Merck & Co NYSE:MRK said last week its tulisokibart ulcerative colitis drug met the main goal and key secondary goals in a late-stage trial, but analysts cited by Reuters said the lack of numerical detail limited read-through for rivals.
Abivax lists Sept. 21 for first-half 2026 results, a fourth-quarter NDA filing for obefazimod in ulcerative colitis, and mid-2027 topline data from a Phase 2b Crohn’s disease induction trial.
