Questions about the legality of the program led the FDA’s then-drug director, Dr. George Tidmarsh, to decline to sign off on approvals under the pathway. The Food and Drug Administration commissioner’s effort to drastically shorten the review of drugs favored by President Donald Trump’s administration is causing alarm across the agency, stoking worries that the plan may run afoul of legal, ethical, and scientific standards long used to vet the safety and effectiveness of new medicines.