The FDA's Center for Biologics Evaluation and Research (CBER) is recovering from the most turbulent period in its recent history. The captain tasked with steadying the ship is Karim Mikhail, who was appointed as the center's director on a permanent basis last month.
CBER—which oversees the regulation of biological products like vaccines and gene therapies—first ran into storms in April 2025. That was when Peter Marks, M.D., Ph.D., who helmed the center for nearly a decade, was forced out after butting heads with Secretary of the Department of Health and Human Services Robert F. Kennedy Jr. over vaccine policy.
Vinay Prasad, M.D., was then tapped to replace Marks. Under Prasad, CBER became one of the most controversial corners of the FDA, particularly when it came to the hot topics of vaccines and rare disease therapies. Prasad's eventful 11-month run at CBER included being briefly ousted from the FDA last summer following a high-stakes regulatory dispute over Sarepta Therapeutics’ Duchenne muscular dystrophy gene therapy Elevidys.
By April 2026, Prasad was also moved on. With the three-week stint of Katherine Szarama, Ph.D., only adding to the sense of a revolving door of directors, Mikhail stepped into the role on an acting basis in mid-May. Then last month, we received confirmation that Mikhail would be staying on permanently.
A pharmacist by training, Mikhail's career before CBER included over two decades at Merck & Co., as well as serving as the CEO of life sciences consulting firm Theodon and cardiovascular biotech Amarin.
“When you start your career, I don't think you could ever plan for becoming a CBER director or try to build experience to get to that place,” Mikhail told Fierce in an interview.
Mikhail stepped into the director's role with a laundry list of challenges to address. On top of the tumultuous changeovers in leadership, CBER and other FDA divisions have seen headcounts drop, including longtime staffers being pushed out or leaving voluntarily amidst broader upheaval last year triggered by the Department of Government Efficiency.
Mikhail admitted that once he arrived at CBER, he had to “prioritize hiring people and prioritize morale.”
Now, he insists CBER is “on the right track,” with some former colleagues returning to the FDA.
“Closer to my circle, I have seen people sort of feeling like we're going back to normality and we're getting back to stability,” he added.
Re-staffing CBER to full strength is only one of Mikhail’s priorities, he told Fierce. Also at the top of his list is “regulatory science innovation and regulatory framework evolution.” In the rare disease arena, the regulatory framework built to decide on approvals is not designed for small patient populations or heterogeneity, Mikhail explained.
Earlier this month, the FDA announced the Rare Disease Framework Initiative to reimagine the development of drugs and biologics for rare diseases. The agency's new framework is designed to speed the development of safe and effective therapies through clearer guidance, greater patient engagement, expert collaboration, and innovative regulatory and scientific approaches. The initiative is spearheaded by the FDA’s Rare Disease Innovation Hub, partnering with the Office of the Commissioner, CBER and the Center for Drug Evaluation and Research.
“If the framework is fit for purpose for rare diseases, then hopefully it will be very predictable because we can actually move forward step by step in the clinical development, focusing on what milestone you need to have,” Mikhail said.
Mikhail has entered this space with all eyes on him. Is he feeling concerned about restoring public trust in the science surrounding rare diseases, especially as this was a point of contention for his predecessors?
“I’m optimistic,” Mikhail told Fierce. “In rare diseases, dogma doesn't always happen, because every case is just very different and you have to apply judgment.”
“However, I think the change that we need is not incremental. It is really big and will require a lot of effort and collaboration,” he added.
His next priority is “evolving the profile of a leader of the FDA” and providing the right culture for the right leader to thrive. He explained that the leaders at the FDA should be people “who not only have the technical skill, but have the progressive thinking to imagine what the field needs to look like in 2030 and beyond.”
This new profile of a leader has to be someone who is not going to make the same mistakes as in the past, or else “we're not adding any value … and I don't know if that's going to help society.”
This ideology comes at a time when the FDA is in limbo, waiting for its nomination for commissioner to be confirmed. The president's pick for the top job, Heidi Overton, M.D., Ph.D., walked a tightrope during her Senate hearing last month as she grappled with questions on hot-button issues like vaccines, abortions, flavored vapes and whether or not President Donald Trump is capable of being wrong.
“I personally believe that she has the right scientific integrity,” Mikhail said of Overton. When asked how he would approach working with his new boss, Mikhail said the two of them “were able to have truthful discussions about what the public needs at the end of the day.”
“Obviously, we're all hoping for the confirmation of Dr. Overton,” he added. “But in the meantime, nobody's sitting there waiting for something to happen.”
With Health Secretary RFK Jr. continuing to bring vaccine-skeptical views into the heart of government, does Mikhail have the confidence to step into the ring with this administration to defend and debate scientific evidence?
“I believe there is complete alignment as to what the public believes; I don't see any misalignment,” Mikhail responded. “What I see is there could be concerns about certain areas, but it's our duty to verify. We cannot have questions from the public and look to the other side as the FDA.”
“I'm not going to hide,” he added. “I personally try to focus very much on what my role is.”
Mikhail sees part of this role as working to restore public trust in CBER and the FDA more widely. The director told Fierce that amidst the scientific debates that happen internally at the FDA, he wishes that sometimes the public could watch and listen in during the safety discussions.
“This is a top priority for me—making sure we are as transparent as possible in our decision-making,” Mikhail vowed. “Anything that we can make public, we will make public because that will enhance public trust.”
Mikhail splits his time between DC and Florida, flying home to the Sunshine State to be with his family on weekends.
“I'm doing the back and forth as it's part of the sacrifice,” he explained. “I could choose not to, but I'm doing it because I feel people deserve a leader who's present.”
Still, with such a weight of responsibility and big plans for his time as director, surely he feels a level of stress in his new role?
“This job is not stressful—that’s not the word—it's intense,” he said.
“Your decision will impact millions of people and, if you care, you will take it very seriously,” Mikhail added. “I take it very seriously. So it is very intense, but at the same time, incredibly gratifying.”
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