Abivax Shares Plunge Over 30% as Cancer Cases Overshadow Inflammatory Bowel Disease Trial Results

Abivax shares tumbled 32% on June 2, 2026 after reporting maintenance trial data for obefazimod in ulcerative colitis. The drug achieved a 40% placebo-adjusted remission rate, but cancer cases on the higher 50 mg dose overshadowed efficacy results. Abivax expects to disclose the full data set in October 2026 and submit for FDA approval in Q4 2026, targeting a 2027 launch.

Abivax stock plunge

• ▪Abivax stock gained nearly 1,700% in 2025.
• ▪Abivax shares tumbled as much as 32% on June 2, 2026 after the company reported fresh data on obefazimod.
• ▪Abivax shares had fallen 7% coming into June 2, 2026 trading.
• ▪Abivax shares were last trading down 31% to a fully diluted market cap of about 7 billion euros on June 2, 2026.

Ulcerative colitis trial results

• ▪Abivax expects a potential launch of obefazimod in 2027.
• ▪Abivax's late-stage trial results for obefazimod in mid-2025 beat even the most optimistic expectations.
• ▪Obefazimod achieved a placebo-adjusted remission rate of about 40% for both doses tested in Abivax's ulcerative colitis trial.
• ▪Abivax expects to submit obefazimod for FDA approval in the fourth quarter of 2026.
• ▪Abivax's trial results published on June 1, 2026 were from a maintenance study assessing obefazimod over 44 weeks.
• ▪David Rubin is director of the inflammatory bowel disease center at the University of Chicago Medicine.

Cancer cases in study

• ▪Abivax expects to disclose the full data set for obefazimod in October 2026.
• ▪Four cases of skin cancer occurred on the higher 50 mg dose of obefazimod in Abivax's trial.

Analyst downgrades

• ▪AbbVie's Rinqvoc carries a U.S. Food and Drug Administration warning of malignancy.
• ▪AbbVie's Rinqvoc generated $8.3 billion in sales in 2025.
• ▪Jefferies downgraded Abivax stock to Hold from Buy following the June 2, 2026 trial results.
• ▪Stifel analyst Damien Choplain views the malignancy signal in Abivax's trial as a potential labelling overhang rather than evidence of a clear causal safety risk.

Takeover speculation impact

• ▪Abivax CEO Marc de Garidel told CNBC in March 2026 that Abivax was in no rush to secure a deal or partnership.
• ▪Stifel analyst Damien Choplain expects Abivax will wait for the full data set expected in October 2026 to gain more granularity and confirm that the malignancies are not related to obefazimod treatment.
• ▪Stifel analyst Damien Choplain expects potential buyers will wait for the full data set expected in October 2026 before making a move on Abivax.
• ▪Abivax was planning to raise money after the June 2026 data readout.

Perspective of Potential acquirers and investors

• ▪Stifel analyst Damien Choplain expects potential buyers will wait for the full data set expected in October 2026 before making a move on Abivax.
• ▪Abivax was planning to raise money after the June 2026 data readout.

Perspective of Equity analysts

• ▪Jefferies downgraded Abivax stock to Hold from Buy following the June 2, 2026 trial results.
• ▪Stifel analyst Damien Choplain views the malignancy signal in Abivax's trial as a potential labelling overhang rather than evidence of a clear causal safety risk.

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