A series of product withdrawals of late on safety grounds, headlined by Merck & Co's decision to pull the painkiller Vioxx (rofecoxib) from the market last year, has led to accusations the FDA has lost sight of its primary function - preserving public safety - in an effort to improve efficiency.
"Given rising public concern over drug safety, and assertions by FDA critics that drug safety in the USA has deteriorated since the adoption of user fees in 1993, we wanted to investigate the matter," said Tufts CSDD director Kenneth Kaitin.
"To date, we have found no evidence that links the rate of drug safety withdrawals and the passage of legislation more than a dozen years ago aimed at speeding new drug approvals. In fact, since 2000, the rate of safety withdrawals in the USA has dropped."
Passed in 1992, the Prescription Drug User Fee Act authorised the FDA to collect fees from drug companies to be used, in part, to hire more reviewers and improve the drug review process. PDUFA was reauthorised in 1997 and again in 2002.
Tufts found that 3.2 per cent of all drugs approved for sale in the US in the 1980s were subsequently withdrawn. The rate rose to 3.5 per cent in the 1990s but since then has been cut in half, dropping to 1.6 per cent.
The Tufts study also suggested that the FDA and industry are becoming more efficient in identifying problem drugs and getting them off the market. The average time between FDA approval and withdrawal on safety grounds fell from 3.7 years in the 1980s to 1.4 years in the 1990s. It is down to 0.7 years - so far - in this decade.
Meanwhile, longer approval times do not assure greater safety, suggests the study. The 2.14 years average approval time for drugs withdrawn since 1980 compares to 2.08 years for all approvals in that time, and faster approval times also do not correlate with safety withdrawals within a therapeutic class, it concluded.