The director of the FDA’s Center for Biologics Evaluation and Research, Dr. Peter Marks, has stepped down from his position, citing fundamental disagreements with Health and Human Services Secretary Robert F. Kennedy Jr. over vaccine policy and scientific integrity.
In his resignation letter to acting FDA Commissioner Sara Brenner, Marks expressed frustration with what he characterized as Kennedy’s promotion of vaccine misinformation. “Despite attempts to address concerns about vaccine safety and transparency, it has become evident that the Secretary is not interested in factual discourse but rather seeks validation of misleading claims,” Marks wrote.
The departure, effective April 5, comes amid a significant measles outbreak that has affected 483 individuals across 20 states and resulted in the first U.S. measles fatality in a decade. Marks specifically referenced Kennedy’s response to the outbreak, which included promoting unproven remedies like cod liver oil while questioning established vaccine safety data.
This resignation leaves both major FDA drug review offices without permanent leadership, following the January departure of Patrizia Cavazzoni. The agency has experienced numerous high-level departures and dismissals in recent months.
Marks, who has led CBER since 2016, played a crucial role in developing Operation Warp Speed, which facilitated the rapid development and deployment of COVID-19 vaccines during the first Trump administration. His tenure was marked by efforts to accelerate cell and gene therapy development, though some of his approaches sparked debate within the industry.
Former FDA Commissioner Robert Califf praised Marks on social media, noting that while his decisions sometimes faced criticism, his primary focus remained public health advancement and patient care in an evolving technological landscape.
The biotechnology sector has expressed concern about the leadership vacuum. John Crowley, who heads the biotech advocacy group BIO, warned that the loss of experienced leadership could compromise scientific standards and impede therapeutic development. Former Alnylam Pharmaceuticals CEO John Maraganore also expressed dismay at Marks’ departure.
The resignation coincides with broader changes at HHS under Kennedy’s leadership. The department recently announced plans to reduce its workforce by 10,000 positions, including 2,400 CDC and 3,500 FDA employees. Additionally, Kennedy’s administration has scrutinized vaccine advisory committees and delayed important CDC advisory meetings.
In his resignation letter, Marks strongly criticized efforts to undermine confidence in established vaccines. “Questioning the reliability of vaccines that have met rigorous FDA standards for decades poses a clear threat to public health and national security,” he stated.
The controversy comes as scientific evidence continues to support vaccine safety and efficacy. The measles vaccine, which Kennedy has questioned, demonstrates 97% effectiveness with two doses and typically causes only mild side effects. Despite Kennedy’s
long-standing claims, no scientific evidence links the vaccine to autism.
While Martin Makary has received Senate confirmation as the new FDA commissioner, it remains unclear when he will officially assume the role. The FDA and HHS have not responded to multiple requests for comment on Marks’ resignation.
The departure of such a senior official has heightened concerns within the pharmaceutical industry, which has generally maintained a cautious approach toward criticizing Trump administration policies affecting the FDA and HHS. Industry leaders worry that the loss of experienced regulators could slow drug development and impact patient access to innovative treatments.