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# 1/3 Accelerated Drugs Have Incomplete Confirmatory Trials
- URL: https://www.fdaweb.com/1-3-accelerated-drugs-have-incomplete-confirmatory-trials/
- Published: 2022-09-30T12:00:00.000Z
- Updated: 2026-09-14T18:01:26.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5152866

More than one-third of accelerated approval drugs (104 of 278 between 1992 and 2021) are past their confirmatory trials’ original planned completion dates, including four that are more than five years past those dates, an HHS Inspector General (IG) data [snapshot ](https://oig.hhs.gov/oei/reports/OEI-01-21-00401.pdf?ref=fdaweb.com)says. The snapshot is part on an ongoing IG evaluation in the wake of the agency’s recent controversial approval of Biogen’s Aduhelm (aducanumab) for treating Alzheimer’s disease ([see earlier story)](https://www.fdaweb.com/uproar-greets-fdas-aduhelm-ok-for-alzheimers/).

The snapshot finds that the 139 applications with completed trials took on average 48 months for FDA to determine that their confirmatory trials were completed. Additionally, it notes that “sponsors may have little incentive to complete trials promptly once they can market a drug under accelerated approval. Likewise, patients may have little incentive to enroll in a confirmatory trial when the therapeutic treatment is already available. Finally, FDA’s process to withdraw a drug approved through the accelerated approval pathway can be lengthy and contentious. These challenges can result in drugs staying on the market—and being administered to patients—for years without the predicted clinical benefit being verified.”