FDA advisers on Thursday voted against GSK's blood cancer drug Blenrep, finding that its risks outweighed its benefits at the selected dose

(Reuters) -GSK shares fell more than 6% on Friday to the bottom of Britain's blue-chip index after a U.S. FDA advisory panel recommended against approving its blood cancer drug Blenrep, citing earlier concerns over side effects.

GSK's blood cancer drug, Blenrep, is under the U.S. Food and Drug Administration (USFDA) spotlight, as staff reviewers raised safety concerns on Tuesday that the drug, when used in combination