FDA Replaces Top Drug and Biologics Directors Days After Makary Exit — Leadership Org Chart Already Updated

The Shake-Up Didn't Stop With Makary

The FDA just lost its commissioner. That wasn't the end of it.

Days after Marty Makary's resignation on May 12, 2026, the agency shuffled the heads of its two most powerful scientific divisions, according to a memo seen by CNBC. The Center for Drug Evaluation and Research (CDER) and the Center for Biologics Evaluation and Research (CBER) — the offices that greenlight every prescription drug and vaccine sold in the United States — both got new acting directors.

Who's In, Who's Out

Tracey Beth Høeg, who had been serving as acting director of CDER, is out. She said so herself — directly, on X — calling it a firing, not a resignation. Katherine Szarama, acting director of CBER, is also out of that role, though according to the CNBC memo she's staying at the agency in some capacity.

Replacing them: Michael Davis, M.D., Ph.D. takes over CDER. Karim Mikhail, M.S. steps into CBER. Lowell Zeta moves into the acting chief of staff role.

The FDA's official organizational chart was updated by Friday night to reflect all of these changes, per the agency's own website.

Acting Commissioner: Kyle Diamantas

With Makary gone, Kyle Diamantas — previously the agency's chief for foods — is now acting FDA commissioner, according to the Associated Press and PBS News. Diamantas is an attorney, NOT a scientist or physician. He also has personal ties to Donald Trump Jr., which PBS noted without elaboration.

The Trump administration told CNBC it hopes to name a permanent commissioner nominee within weeks. That person needs Senate confirmation. Meanwhile the agency is running on acting leadership across the board.

Leadership Turnover at the Core

CDER and CBER are the engine rooms of the FDA. They decide what drugs get approved, what vaccines stay on the market, and what gets pulled. These aren't communications roles or policy desks — they are the core scientific regulatory functions of an agency that, according to CNBC, oversees products accounting for roughly 20% of all U.S. consumer spending.

Davis is now at least the second person to lead CDER since January 2025. CBER has had even more turnover — including Vinay Prasad, who left, came back, then left again after clashing with rare disease patient groups and specialty drugmakers, according to PBS News.

A PBS report, citing the Associated Press, notes that virtually all of the FDA's senior career officials resigned, retired, or were forced out in the first year of Trump's second term.

The Makary Backstory

For readers who missed our previous coverage: Makary resigned under pressure after failing to satisfy multiple constituencies simultaneously. Anti-abortion activists, led by Marjorie Dannenfelser of Susan B. Anthony Pro-Life America, accused him of stalling a review of mifepristone. Vaping lobbyists were furious he initially blocked flavored vape authorizations before reversing course. Pharmaceutical executives didn't trust him either, per Deseret News and the Associated Press.

Trump's own summary, delivered to reporters outside the White House: "He's a great doctor, and he was having some difficulty."

Vacancies Are Stacking Up

The FDA mess is just one piece of a wider problem. The Trump administration is simultaneously trying to fill the director's seat at the Centers for Disease Control and Prevention and the surgeon general post, according to CNBC. The principal deputy commissioner at the FDA is also listed as vacant on the agency's own website right now.

This is the top of the federal public health apparatus. Multiple critical positions. No permanent leadership. Running on acting titles and org chart updates.

Impact on Drug and Vaccine Reviews

If you're waiting on a drug approval, a vaccine recommendation, or a safety review — the people making those calls just changed. The institutions that protect the food and drug supply are being run by people who may or may not have the institutional knowledge to do it right. Leadership churn at this level disrupts drug company timelines and can demoralize career staff who handle thousands of applications annually.