The director of the Food and Drug Administration’s Center for Biologics Evaluation and Research, Peter Marks, submitted his resignation on Friday, citing irreconcilable differences 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 Kennedy’s approach to scientific evidence, stating that the Secretary appeared more interested in promoting misinformation than engaging with factual data. The letter, which was obtained by BioPharma Dive, highlighted Marks’ unsuccessful attempts to address Kennedy’s concerns about vaccine safety and transparency.
Marks’ departure, effective April 5, creates a significant leadership vacuum at the FDA, as both major drug review offices will now lack permanent directors. This follows the January departure of Patrizia Cavazzoni, who previously led the other primary review office. The agency has experienced several high-level departures and dismissals in recent months.
A respected physician and hematologist, Marks has overseen the FDA’s vaccine, blood product, and genetic medicine reviews since 2016. He played a crucial role in conceptualizing Operation Warp Speed, which facilitated the rapid development and deployment of COVID-19 vaccines during the first Trump administration. His advocacy for expedited cell and gene therapy development, though sometimes controversial, helped advance these emerging fields.
Former FDA Commissioner Robert Califf praised Marks’ dedication to public health on Bluesky, noting that while his decisions occasionally sparked disagreement, they were consistently motivated by concern for patient welfare and technological advancement.
The resignation comes amid a measles outbreak that has affected 483 people across 20 states and resulted in one death, the first U.S. measles fatality in a decade. In his resignation letter, Marks specifically addressed Kennedy’s handling of the outbreak, criticizing the promotion of unproven treatments like cod liver oil while questioning established vaccine safety.
The biopharmaceutical industry has expressed alarm over Marks’ departure. John Crowley, who leads the biotech advocacy group BIO, warned that losing experienced FDA leadership could compromise scientific standards and impede therapeutic development. Former Alnylam Pharmaceuticals CEO John Maraganore echoed these concerns on social media.
The resignation coincides with significant changes at HHS under Kennedy’s leadership, including the postponement (and subsequent rescheduling) of a CDC advisory committee meeting and potential modifications to vaccine advisory committees. Most notably, Kennedy recently announced plans to reduce HHS staffing by approximately 10,000 positions, including 2,400 CDC and 3,500 FDA employees.
These developments occur as Martin Makary, President Donald Trump’s nominee for FDA commissioner, received Senate confirmation, though his official installation remains pending.
Marks emphasized in his resignation letter that undermining public confidence in thoroughly tested vaccines poses a significant threat to national health security. He expressed hope that what he termed an “unprecedented assault on scientific truth” would eventually end, allowing Americans to fully benefit from medical advances.
The measles vaccine at the center of recent controversies has demonstrated 97% effectiveness with two doses, with only mild side effects reported in most cases. Despite Kennedy’s long-standing claims, scientific evidence has consistently shown no link between the vaccine and autism.
The Wall Street Journal first reported Marks’ resignation. Requests for comment from both HHS and FDA went unanswered when contacted by BioPharma Dive.