The U.S. Food and Drug Administration is shuffling its top drug and biologics regulators, days after the departure of former commissioner Marty Makary.

Marty Makary's resignation leaves the agency with temporary directors in three top positions, and a number of newly instituted policies with an unclear future.

Dr. Marty Makary's resignation from his post atop the Food and Drug Administration is widening a leadership gap that already existed at the U.S.