Paris, June 2, 2026, 22:08 (CEST)
- Abivax shares in Paris traded at 63.10 euros, down 43.6% for the session.
- Obefazimod hit the main target in a Phase 3 trial for ulcerative colitis maintenance, but shares still dropped.
- Investors zeroed in on malignancy cases seen in the high-dose group, though Abivax said investigators found no link to the treatment.
Abivax shares dropped hard Tuesday, despite positive late-stage trial results for its obefazimod drug. Investors focused on reported cancer and dysplasia cases in patients on the higher dose. The stock traded at 63.10 euros on Euronext Paris, well below Monday’s closing price of 111.80 euros, after touching 62.80 euros earlier. Over in the U.S., its Nasdaq ADRs were last at $72.86, down some 44% late in the session.
Abivax had turned into one of Europe’s biggest biotech bets, as most of its price depended on obefazimod’s prospects as an oral ulcerative colitis drug. Reuters said its shares led the drop on Europe’s STOXX 600 in Paris this morning. The stock had surged over 16 times last year.
Abivax reported late Monday both its once-daily 25 mg and 50 mg doses hit the trial’s primary endpoint. Clinical remission rates reached 50.8% for patients on 25 mg and 51.3% for those on 50 mg. That compared to 10.4% of patients on placebo, the fake treatment.
Abivax reported a placebo-adjusted difference of 39.3 percentage points for the lower dose and 40.3 points for the higher dose. The company said it also hit all main secondary endpoints such as endoscopic improvement and corticosteroid-free remission.
Safety was the issue, or that’s how the market saw it. Abivax’s 50 mg arm had one case each of prostate cancer, breast cancer, and colonic dysplasia, which is abnormal cell growth that can come before cancer. Investigators said the cases weren’t related to treatment, and the company said there was no clustering by organ.
Abivax CEO Marc de Garidel called the data “compelling” with “durable efficacy and favorable safety profile.” In a statement from the company, David T. Rubin of the University of Chicago Medicine said the 44-week data indicated “meaningful efficacy and durable disease control.” Abivax
Some analysts disagreed on what to make of the safety signal. Jefferies called the cancer cases a blow to their thesis, saying it could hurt sentiment even if the link to the drug isn’t clear. Truist Securities said uncertainty over what caused the cases could mean share swings. Laidlaw & Company’s Yale Jen told Reuters the selloff looked like an overreaction and said the readout was a “homerun” for development. Reuters
Some analysts focused on efficacy. Leerink Partners’ Thomas Smith told BioPharma Dive the results “clearly exceeded expectations.” Stifel’s Damien Choplain called the malignancies an “introduced uncertainty” that “cannot be ignored.” BioPharma Dive
Bar remains high in this space. Abivax is pitching obefazimod as a once-daily oral, but AbbVie’s Rinvoq and Takeda’s Entyvio already drive a lot of the conversation on what efficacy, safety, and label language can look like here. Rinvoq has a boxed warning from the FDA for risks that include malignancy.
Abivax’s risk is more visible now. If regulators home in on the malignancy imbalance, the company may get hit with harsher labeling or heavier review before approval. Even if Abivax gets FDA clearance, doctors may hold back. That’s an issue for Abivax, which says it will file a New Drug Application with the FDA late in the fourth quarter of 2026. Label wording influences how widely doctors use new treatments.
Abivax laid out its timeline: half-year financials are due Sept. 21. The company says it’s on track for an ulcerative colitis FDA filing in Q4 and sees topline Phase 2b induction numbers for Crohn’s disease around mid-2027.
Investors didn’t give Abivax much credit for the trial win, sticking to concerns over the safety results. The stock is trading more like a regulatory-risk play right now, even though the potential commercial upside is still on the table.
