Shares of U.S. pharmaceutical and biotechnology companies declined sharply following reports that Peter Marks, head of the FDA's Center for Biologics Evaluation and Research, was forced to resign. His departure marks the highest-profile exit from the agency amid the Trump administration’s ongoing restructuring of federal health bodies. Marks, who was instrumental in the development of COVID-19 vaccines during Trump’s first term, criticized Health Secretary Robert F. Kennedy Jr.'s stance on vaccines in his resignation letter. Investors reacted negatively to the news, with the S&P 500 biotech ETF dropping 4.9 percent, adding to the sector’s losses this year. Companies like Novavax and BioNTech saw their shares fall by up to 8 percent, while gene therapy firms such as Taysha Gene Therapies and Sarepta Therapeutics also posted steep declines.
The broader pharmaceutical sector has been under pressure since Trump returned to office earlier this year, with fears growing that his new tariff policies may target the drug industry. Meanwhile, Kennedy's plans to restructure public health agencies, including the possibility of mass firings, have deepened investor concerns. Analysts warned that Marks’ exit could impact ongoing programs aimed at expediting rare disease treatments and gene therapies, creating further uncertainty over the future leadership and regulatory direction of the FDA.
