U.S. drugmakers saw their stock values tumble on Monday following reports that Peter Marks, the Food and Drug Administration’s top vaccine official, was forced to step down. His departure marks the highest-profile shake-up at the agency as the Trump administration pushes forward with sweeping reforms to federal health institutions.
The pharmaceutical and biotech industries have been under growing pressure since Donald Trump’s return to the White House earlier this year. Investors have been rattled by concerns that Trump’s aggressive tariff policies might extend to pharmaceuticals—an industry that has historically been exempt from such levies. Meanwhile, Health and Human Services Secretary Robert F. Kennedy Jr.’s plans to restructure federal health agencies have added another layer of uncertainty. Kennedy, a long-time environmental lawyer, has been known for his controversial stance on vaccine safety and efficacy.
Marks, who played a pivotal role in Operation Warp Speed during Trump’s first term, is set to exit on April 5, according to his resignation letter, which was first reported by The Wall Street Journal on Friday. In his letter, Marks was critical of Kennedy’s vaccine positions.
The market reacted sharply to the news, with the S&P 500 biotech ETF sinking 4.9%, deepening its roughly 6% decline for the year. Biotech investors, already navigating a challenging economic environment, were further unnerved by the uncertainty surrounding Marks’ departure.
“Biotech has been under serious strain due to broader macroeconomic pressures, and this latest development only adds to investor anxiety,” said BMO Capital Markets analyst Evan Seigerman.
Vaccine manufacturers, including Novavax and BioNTech, saw their shares tumble about 7%, while gene therapy developers such as Taysha Gene Therapies, Solid Biosciences, and Sarepta Therapeutics suffered more severe losses, plunging between 15% and 23%.
Kennedy has indicated that his overhaul of federal public health agencies could involve mass terminations, potentially reshaping the landscape of regulatory oversight.
According to Friday’s reports, Marks was given the ultimatum by a Health and Human Services official—either resign or be fired. As the director of the FDA’s Center for Biologics Evaluation and Research, Marks has championed efforts to fast-track treatments for rare diseases and gene therapies, making his abrupt exit a cause for concern among biotech stakeholders.
“Dr. Marks has been instrumental in advancing biologics, and with no clear successor in place, his departure creates significant near-term uncertainty,” noted William Blair analyst Matt Phipps.
His resignation follows the departure of Patrizia Cavazzoni, the head of the FDA’s drug evaluation division, who left her post just two months ago.
While Marks’ replacement remains unknown, Phipps warned that “there is a distinct possibility that the next appointee could align with Secretary Kennedy’s stance on vaccines.”
Marks has not commented publicly on his departure.