ABVX Tanks 30% After-Hours Despite 51% Remission In Ulcerative Colitis Trial — Rare Cancer Concerns Hit Sentiment

• The treatment showed strong and lasting benefits in 580 adults with moderate to severe ulcerative colitis in the maintenance trial. 
• Both the 25 mg and 50 mg doses achieved the main goal of clinical remission at week 44. 
• Abivax said it remains on track to file for FDA approval of obefazimod in ulcerative colitis by late 2026.

Abivax SA (ABVX) shares fell over 30% in after-hours trading on Monday following the release of late-stage maintenance trial results for the company’s oral ulcerative colitis candidate, obefazimod.

Investors were likely disappointed by the reports of non-melanoma skin cancers and other malignancies in the higher-dose arm, even though the company described them as rare, occurring primarily in older patients, and largely unrelated to treatment.

Study Data: The Positives And Negatives

In the late-stage maintenance trial, obefazimod — an experimental once-daily oral treatment — showed strong and lasting benefits in 580 adults with moderate to severe ulcerative colitis who had already improved during an initial eight-week treatment period.

Both the 25 mg and 50 mg doses achieved the main goal of clinical remission, or major improvement or resolution of symptoms, at Week 44. Roughly 51% of patients on either dose reached remission, compared to just 10.4% on placebo.

The drug also succeeded on all important secondary measures, including visible healing of the colon lining, deeper tissue improvement, and sustained symptom relief without the need for steroids.

Safety was favorable over the 44-week period, with no new concerns identified, and the treatment was generally well tolerated, the company said, while adding that a few patients stopped due to side effects.

While a small number of non-melanoma skin cancers were reported — mainly in patients over age 60 on the higher dose — the company said these were consistent with normal age-related risks and mostly unrelated to the drug.

Abivax said it remains on track to file for FDA approval of obefazimod in ulcerative colitis by late 2026. Additional data from the trial will be presented at upcoming medical meetings, and results from a Crohn’s disease study are expected in mid-2027, it added.

How Did ABVX Retail Traders React?

On Stocktwits, retail sentiment around ABVX rose from ‘neutral’ to ‘extremely bullish’ over the past 24 hours, while message volume jumped from ‘high’ to ‘extremely high’ levels.

A Stocktwits user termed the stock a steal at current prices below $120/share.

Another highlighted the cancer cases observed in the trial.

ABVX stock has soared nearly 2000% over the past 12 months. 

Read More: FULC Stock Slumps Nearly 50% After Hours As FDA Kills Only Clinical Program Over Cancer Risk

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