FILE PHOTO: Signage is seen outside of the Food and Drug Administration (FDA) headquarters in White Oak, Maryland, U.S., August 29, 2020. REUTERS/Andrew Kelly/File Photo

By Christy Santhosh

Dec 2 (Reuters) - The U.S. Food and Drug Administration's drug evaluation chief, Richard Pazdur, is set to retire just weeks after taking the new role, a spokesperson for the health regulator said on Tuesday.

Pazdur, the agency's veteran oncology chief, took over the role on November 11, replacing George Tidmarsh after he resigned amid serious concerns about his personal conduct.

"We respect Dr. Pazdur's decision to retire and honor his 26 years of distinguished service at the FDA," the spokesperson said in a statement.

A federal health official confirmed that Pazdur's departure is imminent, refuting earlier media reports that he could retract his resignation paperwork.

The latest high-profile departure comes as U.S. Health Secretary Robert F. Kennedy Jr. makes stark changes at the agency. Longtime FDA vaccine chief Peter Marks was ousted in April and replaced by Vinay Prasad, an ally of FDA Commissioner Marty Makary.

Days after taking over the new role, Pazdur had questioned a new fast-approval path created by Makary, warning it could pose a risk to public health and be illegal, according to a Washington Post report.

Concerns about the legality of the drug review program, Makary and Prasad inserting themselves into drug review decisions, and Makary's efforts to handpick hires for CDER (the Center for Drug Evaluation and Research) contributed to Pazdur's decision to leave, STAT News reported earlier in the day, citing sources.

"He is one of the most effective and creative regulators in FDA history. With so much attrition already, we're left with a team with very little experience making major decisions," former FDA Commissioner Robert Califf said about the move.

According to RBC Capital Markets analysts, Pazdur's rapid departure is "likely to feed perceptions of internal turmoil at the FDA, adding uncertainty for the biotech sector."

Pazdur joined the FDA in 1999 and was named director of the Office of Oncology Drug Products in 2005. He has been credited with speeding the review process for dozens of cancer drugs.

(Reporting by Christy Santhosh in Bengaluru and Julie Steenhuysen; Editing by Krishna Chandra Eluri, Shinjini Ganguli and Maju Samuel)