Abivax Shares Surge on New Data for Ulcerative Colitis Drug

Shares of French biotech company Abivax soared Tuesday after it released fresh data on its lead drug for bowel disease, clawing back heavy losses from earlier in the month when the same trial had investors questioning the drug's future.

Abivax stock was last trading up 39.9% at 116.5 euros ($133). The move comes after it crashed around 44% on June 2, following a data set that showed there were cancer cases among patients taking the highest dose of its experimental medicine obefazimod for ulcerative colitis (UC).

Additional data on the late-stage clinical trial, released late on Monday, showed that malignancies were in line with levels normally seen in UC patients. The company also said that over 37% of patients who didn't respond to treatment initially, then achieved clinical remission after treatment with a 50 mg dose, after about 10 months.

"These findings suggest that a meaningful proportion of patients who do not initially respond may still derive substantial benefit from longer treatment exposure," Abivax said.

The trial was a so-called maintenance study that tested remission rates among patients with ulcerative colitis over 44 weeks. The Monday update was the second, supplemental part of the Phase 3 trial.

Jefferies analysts called the update "supportive," but said they questioned whether this would be enough for investors given "cancer risk may be tough to discount, sparse catalyst path, cash needs, catalyst path ex-M&A."

Abivax has been positioned as a prime takeover target, with unverified rumors that several Big Pharma companies have their eye set on acquiring the Paris-based clinical-stage biotech.

While it is not uncommon for Abivax or other clinical-stage biotech firms to see wild stock swings following data on their lead, and often only asset, Abivax has grown to become a sizable player with a market cap of about 8 billion euros after shares gained nearly 1,700% in 2025.

Shares had fallen 14% year-to-date coming into Tuesday trading, but were on track to recover from the drop earlier this month when they traded just above 111 euros a share.

The Jefferies analysts said that specialist investors and physicians were likely to put the malignancy issue behind them, but that generalist investors might still be hesitant to own the stock.

Earlier this month, Abivax reported that there were seven cases of different cancers in the study cohort, which were all considered not or unlikely to be related to treatment.

"The expanded cumulative safety data further strengthens our confidence in the long-term safety profile of obefazimod and reinforces the favorable benefit-risk profile for our program as we prepare for our planned [new drug application] submission later this year," CEO Marc de Garidel said in a statement on Monday.

Abivax said it remains on track to submit its NDA to the U.S. Food and Drug Administration for obefazimod in the fourth quarter of 2026. It has previously said that a launch is likely in 2027, but it is widely considered that the company will be acquired before then.

Analysts have described the experimental drug as a potential best-in-class treatment for ulcerative colitis. Abivax is also testing the medicine for Crohn's disease, opening it up to a multi-billion-dollar market for Inflammatory Bowel Disease (IBD).

A trial evaluating the drug in patients with Crohn's disease is expected in mid-2027.