Shares of Abivax completed 43.6% decrease on Tuesday after it reported contemporary knowledge on its lead asset, a drug for ulcerative colitis, wiping out billions in market cap and elevating questions over how a possible takeover of the French biotech may unfold.
The drugs met its endpoints of demonstrating clinically significant efficacy and a placebo-adjusted remission price of about 40% for each doses examined, but additionally confirmed that there have been most cancers instances amongst sufferers taking the upper dose.
“[The] most cancers sign complicates issues,” a Jefferies analyst mentioned. “Even when unrelated noise, we expect the overhang will likely be actual, particularly contemplating absence of different value-inflecting knowledge occasions over the subsequent [year].”
Within the research cohort, there was one reported case every of prostate most cancers, breast most cancers, and colonic dysplasia, which Abivax mentioned have been thought-about unrelated to therapy by investigators, with no organ-specific clustering noticed.
There have been additionally 4 instances of pores and skin most cancers on the upper 50 mg dose, of which two have been deemed not or unlikely associated to the drug, and the opposite two had a medical historical past of pores and skin most cancers, Abivax mentioned.
The Jefferies analysts mentioned that “an affordable clarification” for the most cancers instances was believable however “would not seem to be an simply dismissed overhang,” and downgraded the inventory to Maintain from Purchase.
The Paris-listed inventory gained almost 1,700% in 2025, however shares had fallen 7% coming into Tuesday buying and selling.
Abivax shares year-to-date.
The trial outcomes, printed late Monday, have been from a upkeep research by which Abivax assessed the impact of the drug, obefazimod, over 44 weeks. It comes after the outcomes of a late-stage trial in mid-2025 beat even essentially the most optimistic expectations.
Analysts have described the experimental drug as a possible best-in-class therapy for ulcerative colitis (UC). Abivax can also be testing the medication for Crohn’s illness, opening it as much as a multi-billion-dollar marketplace for Irritable Bowel Syndrome (IBS).
“The novel mechanism, sustained medical remission, and favorable long-term security profile spotlight its potential to handle a big unmet want in UC,” mentioned Abivax’s David Rubin, additionally director of the inflammatory bowel illness middle on the College of Chicago Drugs.
“Whereas the malignancy sign can’t be ignored, we view it as a possible labelling overhang relatively than proof of a transparent causal security danger,” mentioned Stifel analyst Damien Choplain, noting that the efficacy knowledge have been robust.
AbbVie’s Rinqvoc, one other treatment for ulcerative colitis and different inflammatory situations, carries a U.S. Meals and Drug Administration warning of malignancy however nonetheless generated $8.3 billion in gross sales in 2025, he added.
Takeover goal
Abivax has been positioned as a prime takeover goal, with unconfirmed rumors that huge pharma has its eyes on the clinical-stage biotech led by CEO Marc de Garidel.
De Garidel informed CNBC in March that he was assured the upkeep research would learn out positively, and signaled that the corporate was in no rush to safe a deal or a partnership, as phrases can be higher after it.
It has been extensively anticipated that Abivax can be acquired earlier than launching obefazimod, and de Garidel informed CNBC that it was planning to boost cash after the June knowledge readout. The corporate on Monday reiterated the expectation to submit obefazimod for FDA approval within the fourth quarter and a possible launch in 2027.
In keeping with Choplain, the almost certainly state of affairs now’s that Abivax will await the total knowledge set, which is anticipated to be disclosed in October, to realize extra granularity and ensure that the malignancies are usually not associated to the therapy.
It additionally appears affordable to imagine that potential consumers will await the total knowledge set earlier than making a transfer, he informed CNBC through electronic mail on Tuesday.
