Importance: US law requires testing of new drugs before approval to ensure that they provide a well-defined benefit that is commensurate with their risks. A major challenge for the US Food and Drug Administration (FDA) is to achieve an appropriate balance between rigorous testing and the need for timely approval of drugs that have benefits that outweigh their risks.
Objective: To describe the evolution of laws and standards affecting drug testing, the use of new approval programs and standards, expansions of the role and authority of the FDA, and changes in the number of drugs approved from the 1980s to 2018.
Evidence: Sources of evidence included principal federal laws and FDA regulations (1962-2018) and FDA databases of approved new drugs (1984-2018), generic drugs (1970-2018), biologics (1984-2018), and vaccines (1998-2018); special development and approval programs (Orphan drug [1984-2018], Fast-Track [1988-2018], Priority Review and its predecessors [1984-2018], Accelerated Approval [1992-2018], and Breakthrough Therapy [2012-2018]); expanded access (2010-2017) and Risk Evaluation and Mitigation Strategies (2008-2018); and user fees paid to the FDA by industry (1993-2018).
Findings: From 1983 to 2018, legislation and regulatory initiatives have substantially changed drug approval at the FDA. The mean annual number of new drug approvals, including biologics, was 34 from 1990-1999, 25 from 2000-2009, and 41 from 2010-2018. New biologic product approvals increased from a median of 2.5 from 1990-1999, to 5 from 2000-2013, to 12 from 2014-2018. The median annual number of generic drugs approved was 136 from 1970 to the enactment of the Hatch-Waxman Act in 1984; 284 from 1985 to the enactment of the Generic Drug User Fee Act in 2012; and 588 from 2013-2018. Prescription drug user fee funding expanded from new drugs and biologics in 1992 to generic and biosimilar drugs in 2012. The amount of Prescription Drug User Fee Act fees collected from industry increased from an annual mean of $66 million in 1993-1997 to $820 million in 2013-2017, and in 2018, user fees accounted for approximately 80% of the salaries of review personnel responsible for the approval of new drugs. The proportion of drugs approved with an Orphan Drug Act designation increased from 18% (55/304) in 1984-1995, to 22% (82/379) in 1996-2007, to 41% (154/380) in 2008-2018. Use of Accelerated Approval, Fast-Track, and Priority Review for new drugs has increased over time, with 81% (48/59) of new drugs benefiting from at least 1 such expedited program in 2018. The proportion of new approvals supported by at least 2 pivotal trials decreased from 80.6% in 1995-1997 to 52.8% in 2015-2017, based on 124 and 106 approvals, respectively, while the median number of patients studied did not change significantly (774 vs 816). FDA drug review times declined from more than 3 years in 1983 to less than 1 year in 2017, but total time from the authorization of clinical testing to approval has remained at approximately 8 years over that period.
Conclusions and relevance: Over the last 4 decades, the approval and regulation processes for pharmaceutical agents have evolved and increased in complexity as special programs have been added and as the use of surrogate measures has been encouraged. The FDA funding needed to implement and manage these programs has been addressed by expanding industry-paid user fees. The FDA has increasingly accepted less data and more surrogate measures, and has shortened its review times.