Crawford was appointed acting FDA Commissioner March 2004, after having stepped into the job on an interim basis on two prior occasions.
He has been acting Commissioner since Mark McClellan departure left to head up the Centres for Medicare & Medicaid Services, and after a long, contentious and drawn-out appraisal process was finally granted the permanent position in July.
However, his application for the permanent post and subsequent tenure has been dogged by persistent criticism on issues such as the FDA's recent record on monitoring drug safety - a debate brought to a head by the withdrawal of Merck & Co's painkiller Vioxx (rofecoxib) - the politically-sensitive issue of expanding access to emergency contraception and his opposition to the re-importation of prescription drugs.
The FDA's postponement last month of a decision on whether Barr Laboratories' emergency contraceptive Plan B should be made available over-the-counter - which prompted 13 US Senators to seek a non-partisan probe into the agency's actions and the resignation of assistant FDA Commissioner for Women's Health Susan Wood - has been a key source of criticism for the Commissioner.
At the time, Crawford said that unresolved regulatory issues made it impossible to approve expanded use of the emergency contraceptive, particularly whether the same drug could be sold both by prescription and over-the-counter for the same indication.
In his resignation letter, Crawford said that at the age of 67 it was time to step down, while the department of Health and Human Services, which oversees the FDA, said the decision was made for personal reasons.
President George W Bush has asked the National Cancer Institute's director, Dr Andrew von Eschenbach, to be the FDA's new acting commissioner while a permanent replacement is found.
- Meanwhile, the FDA said it has selected Dr Douglas Throckmorton as the deputy director of the Centre for Drug Evaluation and Research (CDER).
Dr Throckmorton joined FDA in 1997 and has been acting Deputy Director of CDER since May 2004.
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