** Shares in Abivax ABVX.PA are expected to fall between 15% and 25% after the French biotech company published the late-stage trial results for its inflammatory bowel drug

** Abivax says more than half of patients experienced clinical remission during the study against 10.4% on placebo

** There were three cancer cases among patients taking the higher dose, though investigators considered them unrelated to the treatment, the company says

** "Cancer cases seen in maintenance break our thesis," says Jefferies

** "Even if proven to be not drug-related or very low incidence, we expect an overhang to investor interest, strategic optionality, and commercial uptake," the brokerage adds

** Truist Securities says safety is the notable eyebrow-raiser from the topline results, but causality is still up for debate and likely to drive volatility

** Abivax was down 7% YTD as of Monday's close; ADRs fell 23% after hours