** U.S.-listed shares of French biotech firm Abivax ABVX.O up 3.6% to $138 in premarket trading on Weds after above-target $800 mln follow-on priced

** Co announces 6.4 mln American Depositary Shares (ADSs) at $125

** Offering size boosted from $600 mln

** ABVX's U.S.-listed shares jumped ~39% to close at $133.26 on Tues after its inflammatory bowel drug, obefazimod, showed it helped harder-to-treat patient groups achieve remission

** Co intends to use net proceeds from offering for expenses relating to potential commercialization of obefazimod in the U.S., clinical R&D expenses, primarily related to ulcerative colitis and Crohn’s disease, among other purposes

** Leerink, Morgan Stanley, Piper Sandler and Guggenheim joint bookrunners, along with LifeSci Capital as passive bookrunner

** On June 2, U.S.-listed plunged 44% to $72.50 after co published its first late-stage trial data, as investors focused on cancer cases reported in patients taking the higher dose, although investigators considered the cases unrelated to treatment