Abivax shares sink after key trial results for inflammatory bowel drug (updated)

Abivax SA

02/06/2026 09:19

(Writes through with details on study and drug, analyst comments
on the share reaction and possible safety concerns)

        *    Shares of French biotech company drop 30%     

        *    Abivax trial meets main goal for inflammatory bowel
drug     

        *    Unrelated cancer cases trigger selloff     

        *    Analysts praise results despite safety concerns     

  
    By Gianluca Lo Nostro
       June 2 (Reuters) - Abivax  ABVX.PA  shares tumbled on
Tuesday after the French biotech reported late-stage data for
its experimental inflammatory bowel drug, with investors
focusing on safety concerns even as the treatment showed strong
efficacy.
    The shares were down 30% in early Paris trading, leading
losses on Europe's STOXX 600  .STOXX  benchmark index, after a
spectacular rally last year that saw the stock rise more than
16-fold.
    Obefazimod is an oral drug being developed for ulcerative
colitis, a chronic disease that causes inflammation and ulcers
in the colon. In a 44-week maintenance study, 50.8% of patients
on the 25 mg dose and 51.3% on the 50 mg dose achieved clinical
remission, compared with 10.4% on placebo.
    Both doses met the trial's main goal, showing respective
placebo-adjusted remission rates of 39.3% and 40.3%, among the
strongest reported in a large ulcerative colitis programme.
    However, three patients on the 50 mg dose had one case each
of prostate cancer, breast cancer and colonic dysplasia. Abivax
said in its report on the study, published on Monday, that
investigators considered the cases unrelated to treatment.
    In a note to investors, Jefferies analysts said the cancer
cases "broke" its investment thesis, as they may hang over the
sentiment regardless of the reason.
    "Even if proven to be not drug-related or very low
incidence, we expect an overhang to investor interest, strategic
optionality, and commercial uptake," they wrote.
    Truist Securities analysts also said that safety questions,
with causality still up for debate, were likely to drive share
volatility, even though the drug's efficacy was impressive.
    Abivax was not immediately available for additional comment
on concerns over the cancer cases.
    On the other hand, Yale Jen, senior managing director at
brokerage Laidlaw & Company, said the selloff could be an
overreaction toward any safety concerns, while calling the
overall results a "homerun" for the drug's development.

(Reporting by Gianluca Lo Nostro; Editing by Milla
Nissi-Prussak)
((mailto:gianluca.lonostro@thomsonreuters.com;))