Abivax Shares Tumble 44% After Cancer Signal in Ulcerative Colitis Trial; ‘Pharma Bro’ Shkreli Compares Risk to GLP-1 Concerns
Abivax SA (ABVX) suffered its steepest one-day decline on Tuesday, with shares plunging 44% after the biotech firm reported that some patients in a Phase 3 ulcerative colitis trial developed skin cancers and other malignancies. The selloff came despite the drug, obefazimod, achieving strong efficacy results that analysts described as best-in-class.
Martin Shkreli, the controversial former hedge fund manager and pharmaceutical executive widely known as ‘Pharma Bro,’ weighed in on the situation via social media platform X. “Not much to think. It sucks. But happens all the time and should pass with time,” Shkreli wrote. He referenced exenatide — the first GLP-1 drug, marketed as Byetta — which faced early safety signals involving thyroid C-cell tumors in animal studies. “GLPs are doing fine. Every trial is a roll of the dice,” he added.
Shkreli’s comments highlight a historical precedent: initial safety concerns around GLP-1s ultimately gave way to widespread approval and commercial success. Today, drugs like Ozempic and Mounjaro are among the biggest blockbusters in obesity care. Shkreli himself rose to notoriety in 2015 for raising the price of the antiparasitic drug Daraprim by more than 5,000% while CEO of Turing Pharmaceuticals.
Abivax’s trial enrolled 580 patients and tested two doses of obefazimod (25 mg and 50 mg). At week 44, roughly 51% of patients on either dose achieved clinical remission versus 10.4% on placebo. The drug also met all key secondary endpoints, including endoscopic healing, histologic improvement and sustained symptom relief without steroids. However, the results were overshadowed by reports of non-melanoma skin cancers and other malignancies, primarily among patients over 60 in the higher-dose arm.
Abivax stated that the cancer cases were rare, consistent with age-related background risks, and largely unrelated to the drug. The company added that safety was otherwise favorable and that it remains on track to file for FDA approval of obefazimod in ulcerative colitis by late 2026.
Analysts were divided on the implications. Jefferies downgraded Abivax to ‘Hold’ from ‘Buy’ and slashed its price target to $90 from $160, implying roughly 30% downside from Monday’s close. Analyst Faisal Khurshid noted that while the efficacy data was best-in-class, the cancer signal “complicates matters” and that the “overhang will be real” given no major data catalysts expected for the next year.
Wedbush took a slightly more constructive view, upgrading Abivax to ‘Neutral’ from ‘Underperform’ but lowering its price target to $90 from $110. The firm acknowledged that the cancer cases increase the risk of a future black box warning and could create hurdles to FDA approval. A black box warning indicates a product carries a significant risk of severe, life-threatening or permanently disabling adverse effects.
Despite the sharp stock drop, retail sentiment on Stocktwits remained ‘extremely bullish’ over the past 24 hours, with message volume staying at ‘extremely high’ levels. Over the trailing 12 months, ABVX shares have still soared nearly 1,000%.
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Anan Ashraf has no position in any of the stocks mentioned in this article. StockTwits' news team content is for informational purposes only and is not intended as investment advice. For more, see our editorial policy. This article was originally published on StockTwits.
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