FDA Office of New Drugs director John Jenkins said concerns over drug safety and “gaming” of the review clock were not to blame for a significant drop in first-cycle approvals, instead attributing the decline to historical fluctuations.

Speaking at a Citigroup Washington Biopharm Symposium, Jenkins pointed to the approval of new molecular entity (NME) drugs, where “historically about 75% of those submitted are eventually approved, and there is no evidence this has changed.”

There have been no management directives to either “speed up” or “slow down” reviews, he said. “A major factor supporting or limiting approval is the quality of the application and the data.”

FDA statistics show approval letters for standard-reviewed NMEs have been dropping over the past two years: 38% of the 16 NMEs submitted in 2003 were approved in their first review cycle, compared with 20% of 15 in 2004, and only 7% of the 14 in 2005. During the same period, the use of delay-causing “approvable” letters increased from 56% to about 64%.