Trends in the Quality of Evidence Supporting FDA Drug Approvals: Results from a Literature Review.

CONTEXT: New drug approvals in the United States must be supported by substantial evidence from "adequate and well-controlled" trials. The Food and Drug Administration (FDA) has flexibility in how it applies this standard. METHODS: The authors conducted a systematic literature review of studies evaluating the design and outcomes of the key trials supporting new drug approvals in the United States. They extracted data on the trial characteristics, endpoint types, and expedited regulatory pathways. FINDINGS: Among 48 publications eligible for inclusion, 30 covered trial characteristics, 23 covered surrogate measures, and 30 covered regulatory pathways. Trends point toward less frequent randomization, double-blinding, and active controls, with variation by drug type and indication. Surrogate measures are becoming more common but are not consistently well correlated with clinical outcomes. Drugs approved through expedited regulatory pathways often have less rigorous trial design characteristics. CONCLUSIONS: The characteristics of trials used to approve new drugs have evolved over the past two decades along with greater use of expedited regulatory pathways and changes in the nature of drugs being evaluated. While flexibility in regulatory standards is important, policy changes can emphasize high-quality data collection before or after FDA approval.

Analysis of Supportive Evidence for US Food and Drug Administration Approvals of Novel Drugs in 2020.

Importance: In recent years, drug approvals have been based on fewer, smaller, and less rigorous pivotal trials. Less robust preapproval testing raises questions about the efficacy and clinical value of these drugs. Objective: To assess the regulatory context, pivotal design characteristics, and postmarket requirements (PMRs) and postmarket commitments (PMCs) of novel 2020 drug approvals to characterize the state of evidence at the time of approval. Design, Setting, and Participants: This cohort study identified novel drugs approved by the US Food and Drug Administration's (FDA) Center for Drug Evaluation and Research in 2020. The Drugs@FDA database was used to extract key characteristics of each drug's pivotal trials. Drug approval packages provided regulatory information. The prevalence of key trial design features was compared between oncology and nononcology drugs. Exposures: Drug names, date of approval, indication on labeling, and clinical and regulatory details. Main Outcomes and Measures: Number of pivotal trials, pivotal trial design (randomization, masking, groups), trial comparator, trial hypothesis, trial end points, results, number and type of expedited pathway designations, and number and type of PMRs and PMCs. Results: The 49 novel therapeutics approved in 2020 were supported by 75 pivotal trials. More than half of drugs (28 [57.1%]) were supported by a single pivotal trial. Trial sizes ranged from 19 to 2230 participants. More than three-fourths of trials (57 [76.0%]) had a randomization component, and nearly two-thirds (46 [61.3%]) were double-masked. Most used a superiority approach. Roughly half (39 [52.0%]) compared the novel therapeutic with a placebo or vehicle control; 13 (17.3%), an active control; 2 (2.7%), both a placebo and active control; and 21 (28.0%), a historical, external, or other control. Nearly half of pivotal trials (34 [45.3%]) used a surrogate measure as a primary end point. Pivotal trials supporting oncology approvals were much more likely to have historical controls than nononcology approvals (13 of 18 [72.2%] vs 8 of 57 [14.0%]; P < .001) and to use at least 1 surrogate measure as a primary end point (17 [94.4%] vs 17 [29.8%]; P < .001). Forty drugs had at least 1 PMR or PMC, accounting for 178 PMRs and PMCs across the cohort. Conclusions and Relevance: These findings suggest that the increased flexibility in the characteristics of acceptable preapproval evidence can be partially explained by the increase in trials of drugs for rare and other serious conditions that require flexible testing strategies as well as the associated regulatory changes that have accumulated over time. The FDA and consumers may benefit from a revised approach that better balances time to market with ensuring that approved drugs show evidence of efficacy.

New Drug Postmarketing Requirements and Commitments in the US: A Systematic Review of the Evidence.

INTRODUCTION: After the approval of a new drug, the Food and Drug Administration (FDA) may issue postmarketing requirements (PMRs), studies that the law requires manufacturers to conduct for drugs approved under certain conditions, and postmarketing commitments (PMCs), studies that the FDA and manufacturers agree should be conducted as a condition of approval. OBJECTIVE: With regulators' increasing reliance on gathering important evidence after initial product approval, we sought to assess the track record of PMRs and PMCs by synthesizing information about postmarketing study completion rates, timeliness, study types, and results reporting. METHODS: A systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted. Studies published in academic journals or government reports that reported original data about the characteristics of PMRs or PMCs were included. Studies of post-approval trial mandates issued by regulators outside the USA were excluded, as were those that addressed post-approval research without mentioning either PMCs or PMRs or a specific approval pathway associated with statutorily required PMRs. Two investigators independently screened and extracted data from studies and reports. Data sources included the Federal Register from 2003 to 2020, FDA backlog reviews from 2008 to 2020, PubMed from January 2006 to April 2021, and the US Government Accountability Office (GAO) database for reports from January 2006 to April 2021. PMR/PMC characteristics (e.g., completion rates, timeliness, results reporting, outcomes) were not meta-analyzed due to the heterogeneity in study designs. RESULTS: Twenty-seven peer-reviewed articles from PubMed, five GAO reports, 17 annual Federal Register notices, and 12 annual backlog reviews were included. Among the 27 studies, 13 reviewed PMRs and PMCs, one reviewed only PMCs, and 13 reviewed only PMRs. A majority of new drugs were approved with at least one PMR or PMC. PMCs were completed at higher rates than PMRs, although delays were common and neither was found to be completed more than two-thirds of the time. Over two-thirds of PMRs and PMCs reported their findings in publications and trial registries. Over half of PMCs and PMRs produced novel information for clinical practice or leading to regulatory action, such as confirmation of benefit or a labeling change. CONCLUSION: PMRs and PMCs are common for new drugs and can lead to worthwhile outcomes, but are often delayed or incomplete. Greater attention is needed to timely completion, improving transparency of findings, and ensuring that PMRs and PMCs produce optimally useful information for prescribers and patients.