FDA neuroscience chief Billy Dunn, who led Aduhelm approval, will leave agency

The FDA’s top neuroscience expert Billy Dunn, who was embroiled in controversy over his close ties with industry ahead of two key Alzheimer’s drug approvals, has decided to leave the agency effective immediately, according to an internal email obtained by Endpoints News.

Billy Dunn

“Billy has decided to retire from the FDA and explore other opportunities while continuing his focus on improving the lives of patients with neurological diseases,” Peter Stein, head of the Office of New Drugs, said in the email.

Dunn’s departure follows several high-profile drug approvals that raised questions about the agency’s coziness with Biogen regarding its approval of the amyloid-targeted drug Aduhelm and led to a highly critical congressional report.

Stein’s email to staff on Monday didn’t say where Dunn is headed. It noted his fast rise from joining FDA’s division of neurological products in 2005 to being named the director of the division in 2013, and ultimately rising to the top of the Office of Neuroscience, which was created in 2020 as part of an agency overhaul.

“He has provided thoughtful direction for individual IND development programs and has also moved the field more broadly through innovations in trial designs and endpoints, clarifying how drugs targeting particular disorders can be more efficiently developed,” Stein said.

Dunn didn’t immediately respond to an attempt to reach him on Monday.

Aduhelm approval

Last month’s congressional report on Aduhelm’s approval found that the FDA and Biogen engaged in “at least 45 collaborative workstream meetings” that Dunn and Samantha Budd Haeberlein, Biogen’s head of clinical development, attended and that were outside the normal scope of FDA-sponsor meetings.

The FDA’s own report on the matter said that the meetings between Biogen and the agency were “not typical of other development programs,” but the agency ultimately legitimized the approval by concluding that the interactions “were consistent with the agency’s public health mission given the potential for the first disease modifying drug for Alzheimer’s disease.”

Teresa Buracchio, deputy of the Office of Neuroscience, will take over Dunn’s role as director on an acting basis. Buracchio joined FDA in 2013 as a reviewer in the division of gastroenterology and inborn error products, before moving in 2014 to the division of neurology products.  In 2017, she was promoted to team leader in DNP, which became the Division of Neurology I, where she was named division director in 2021.  Since last November, Buracchio has been the acting deputy of the Office of Neuroscience.

Immediate ripple effects

As the news of Dunn’s departure hit the markets, Reata Pharmaceuticals saw its stock price $RETA fall by more than 34% at one point on Monday afternoon. Reata is due for a decision from the FDA before tomorrow on its omaveloxolone for the treatment of Friedreich’s ataxia.

Dunn’s departure likely means a more stringent FDA, and in its Q2 report, Reata noted that the FDA was concerned about the efficacy of omaveloxolone. The Plano, TX-based biotech said that in response to those concerns, it submitted additional data from its clinical trial. But in order to review that new data, the FDA needed three more months.

Friedreich’s ataxia is a rare genetic disease in which nerve fibers degenerate over time. SVB Securities analysts wrote in a note on the Reata situation on Monday:

We view the timing of Dunn’s departure as curious; however, we also note that given the proximity to the PDUFA, the decision for omav has likely already been made. As we have outlined previously (Have We Seen This Movie Before? Musings on Omav’s Dance With the FDA), prior comments from Billy Dunn during the regulatory review for Albrioza [Relyvrio] suggested that the FDA is trying to be flexible for rare central nervous system/CNS diseases; however, it remains unclear if this also reads through to omaveloxolone/omav in Friedreich’s ataxia/FA. There is even more uncertainty now that Billy Dunn is leaving the agency, especially as he was a major pillar to the bull thesis, with investors assuming that the FDA was going to continue with the flexible stance and acquiesce with omav.

Editor’s note: The spelling of Teresa Buracchio’s name was incorrect in a previous version of this story and has been corrected. 

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