However, a study in the journal Health Affairs (December 17) has revealed that this programme has not had any impact on approval times. In the 10 years since PDUFA took effect, companies have paid about $1 billion in fees.
The researchers, from the University of Michigan and Harvard University, say their findings also refute claims that the fee-based system might cause the FDA to give special treatment to larger, more powerful drug companies. They found no evidence that those firms got faster approvals for their products.
Data was compiled on 843 new drugs submitted to the FDA for approval between 1977 and 2000, including 320 drugs that were rejected. This timeframe enabled the researchers to see trends both before and after the passage of the Prescription Drug User Fee Act (PDUFA) in 1992. PDUFA set fees that companies pay to the FDA, to offset the cost of hiring additional reviewing staff.
They looked at approval times for the drugs submitted in each year, and concurrent levels of FDA drug-review staffing. The analysis also included scrutiny of each drug's disease indications, and each drug company's sales totals, number of recent FDA submissions and lobbying budget.
Overall, the average time from a drug's submission to its approval decreased dramatically over the 13 years studied, from 24 to 36 months in the 1980s to roughly 14 months in the late 1990s. The researchers also report that the number of FDA staff reviewing drug applications rose steadily throughout the period from 1980 to 1998.
But staffing levels were growing rapidly for about five years before PDUFA took effect, because of increased federal funding to the FDA budget. The researchers concluded that this prolonged, steady rise in review staff, and not any particular aspect of PDUFA, was responsible for the drop in approval times.
Mark Fendrick of U-M, one of the senior authors on the study, said: "The bottom line is that the more staff the FDA has reviewing drug applications, the faster the approval process will be. If you want more rapid assessment of new drugs, hire more people. And if you're still concerned about external influence or potential conflicts, fund them through additional mechanisms."
In all, the average review time for a drug dropped by 3.3 months for every 100 additional FDA staff hired. If FDA staffing had stayed constant at 1980 levels throughout the 1980s and 1990s, the researchers show, average drug approval time would have stayed at around 24 months.
"The effect of enhanced staffing levels on decreasing approval times was substantial and observable several years before PDUFA was passed. Analyses designed to identify other effects of PDUFA, beyond those attributable to increased staff, were unrevealing," commented lead author Daniel Carpenter of Harvard.
While the source of the funding for additional staff doesn't appear to affect the speed of the review process, some critics have faulted the industry fee program for allegedly compromising the FDA's independence in other ways, or for speeding up approvals so much that dangerous side effects are overlooked. Effects beyond approval time, such as the quality of review or the number of recalls among the drugs that received approval, were not studied in the current report.
The study was motivated by several high-profile critiques of the PDUFA system, including allegations that the FDA had become a 'servant of industry'.