Prasad's tenure was generally marked by controversy, but he is departing amid a cluster of self-destructive decisions. Those include a shocking rejection of an mRNA vaccine (which was over the objections of agency scientists and quickly reversed); a demand for an additional clinical trial on a gene therapy for Huntington's disease, which was widely seen as moving the goalpost for the therapy; his startling choice to publicly attack the maker of that gene therapy, UniQure; and alleged abuse of FDA staff, who say he created a toxic work environment.