The director of the FDA’s Center for Biologics Evaluation and Research, Peter Marks, has stepped down from his position, citing fundamental disagreements with Health and Human Services Secretary Robert F. Kennedy Jr.’s stance on vaccine safety.
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 efforts to address concerns about vaccine safety and transparency, it has become evident that the Secretary is not interested in scientific truth, but rather seeks validation of his misguided beliefs,” Marks stated in the letter obtained by BioPharma Dive.
The departure, effective April 5, comes amid a significant measles outbreak affecting 483 individuals across 20 states, resulting in the first U.S. measles fatality in a decade. Marks specifically referenced Kennedy’s controversial response to the outbreak, including the promotion of unproven remedies like cod liver oil, which can be harmful in large doses.
The 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 accelerated COVID-19 vaccine development during the first Trump administration. His tenure was marked by advocacy for cell and gene therapy advancement and efforts to streamline agency processes.
Former FDA Commissioner Robert Califf praised Marks on Bluesky, noting that while his decisions sometimes sparked debate, his primary focus remained public health and patient needs in an evolving technological landscape.
The biotechnology industry has expressed concern about the leadership vacuum. BIO’s head John Crowley warned that the loss of experienced leadership could compromise scientific standards and impede
therapeutic development. John Maraganore, former Alnylam
Pharmaceuticals CEO, also expressed regret over Marks’ departure.
In his resignation letter, Marks strongly criticized efforts to undermine confidence in established vaccines, calling such actions “irresponsible” and “detrimental to public health.” He emphasized that the measles vaccine’s effectiveness is well-documented, with two doses providing 97% protection and minimal side effects, contrary to Kennedy’s longstanding claims linking vaccines to autism.
The resignation coincides with significant changes at HHS under Kennedy’s leadership, including the postponement (later rescheduled) of CDC advisory committee meetings and potential removal of committee members. According to Politico, Kennedy is reviewing other vaccine advisory committees as well.
The developments occur against the backdrop of broader Trump administration initiatives to reduce government workforce and scientific research funding. Kennedy recently announced plans to cut 10,000 HHS positions, including 2,400 CDC and 3,500 FDA employees.
Meanwhile, Martin Makary, President Trump’s nominee for FDA
commissioner, received Senate confirmation on Tuesday, though his official installation remains pending. The timing of these leadership changes has created uncertainty within the pharmaceutical industry, which has maintained a cautious approach toward criticizing Trump administration policies affecting HHS and the FDA.
Marks concluded his resignation letter by expressing hope for an end to what he termed an “unprecedented assault on scientific truth” that he believes has negatively impacted national public health, preventing Americans from fully benefiting from medical advances.