Abivax shares surge as worries subside over immune drug’s cancer risk

An article from Dive Brief Abivax shares surge as worries subside over immune drug’s cancer risk According to Abivax, fresh data suggest malignancy rates in its trials were no higher than “background” ones for people with ulcerative colitis, clearing a key safety concern. Published July 1, 2026 Jonathan Gardner Senior Reporter Share Copy link Email LinkedIn X/Twitter Facebook Print License Add us on Google Dive Brief: Shares of Paris-based biotechnology company Abivax surged nearly 40% Tuesday following the release of supplementary Phase 3 data on its inflammatory bowel disease drug that cleared away investors’ concerns about increased cancer risk. Abivax said cancer rates seen across enrollees in its Phase 2 and Phase 3 trials were no higher than the “background” one seen in people with ulcerative colitis, which is higher than the general population in certain types of malignancies. The update from the second part of that Phase 3 trial — which enrolled people who didn't respond to the drug or relapsed during the trial — added safety data that “appropriately addresses the key overhang facing the stock,” wrote Jefferies analyst Faisal Khurshid in a client note. Abivax followed the share price increase with an $800 million sale of its U.S. listed shares. Dive Insight: Until a month ago, Wall Street analysts had viewed Abivax’s drug, called obefazimod, as having “best-in-disease” efficacy, potentially offering an oral alternative to biologics like Takeda Pharmaceutical’s Entyvio that also doesn’t carry the cardiovascular or infection risk of pills like AbbVie’s Rinvoq or Bristol Myers Squibb’s Zeposia. However, investigators in obefazimod’s Phase 3 trial identified some cancer cases in the highest dose tested, sparking a share sell-off by investors worried about potential restrictions placed on its use or warnings that could discourage uptake. Tuesday’s update changed that picture. The company released further data based on “exposure-adjusted incidence rates” that suggested the cancer risk is no higher than what is seen in people with ulcerative colitis. The disorder puts people at higher risk of colorectal cancer because of chronic inflammation, while some medications can increase photosensitivity and raise the risk of skin cancers. The “totality” of obefazimod’s safety data, covering more than 1,700 patient-years of exposure, “suggests no ‘real’ malignancy signal above that observed in the background UC patient population,” wrote Leerink Partners analyst Thomas Smith in a client note. Obefazimod differs from biologics and other small-molecule drugs to treat inflammatory bowel disease, boosting the expression of “microRNA-124,” which results in fewer biological signals inducing inflammation. Abivax launched more than a decade ago as a biotech developing the drug as an HIV treatment before pivoting to ulcerative colitis in 2017. Abivax is planning to submit an approval application to the Food and Drug Administration by the end of 2026. The company sold shares to finance the potential commercialization of obefazimod as well as continue researching it in other inflammatory bowel diseases, although it has been rumored as a big pharma acquisition target. Add us on Google Share Copy link Email LinkedIn X/Twitter Facebook Print License Filed Under: Biotech, Clinical Trials