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.