FDA Publishes 200+ Complete Response Letters to Increase Transparency on Drug Approval Decisions
The US Food and Drug Administration (FDA) has publicly released more than 200 complete response letters (CRLs) issued between 2020 and 2024, marking a major move toward increased transparency in its drug and biologic review process. These documents detail the reasons why the FDA declined to approve a drug application and are now available on the agency’s openFDA platform.
CRLs are issued when the FDA completes a review of a drug or biological product application and determines that approval cannot be granted in its current form. Common issues cited include safety or efficacy concerns, manufacturing deficiencies, and bioequivalence problems. Historically, the FDA did not publish CRLs for pending or even final applications, leaving interpretation of the agency’s rationale solely to the sponsor. Each letter outlines the FDA’s findings and, in many cases, provides recommendations for how sponsors can address deficiencies.
“For far too long, drug developers have been playing a guessing game when navigating the FDA,” said FDA Commissioner Marty Makary, MD, MPH. “Drug developers and capital markets alike want predictability. So today we’re one step closer to delivering it to them, with an ultimate goal of bringing cures and meaningful treatments to patients faster.”
The publication of these letters is part of the FDA’s broader initiative to modernize regulatory practices and reduce the opaqueness of drug development setbacks. A 2015 FDA analysis found that sponsors omitted 85% of the FDA’s concerns about safety and efficacy in their public disclosures and failed to mention new trial requirements 40% of the time.
By releasing redacted CRLs associated with since-approved applications, the FDA aims to provide the industry with a clearer understanding of regulatory expectations and reduce the repetition of common mistakes. Additional CRLs are expected to be published from the agency’s archives as this initiative progresses.
Reference
FDA embraces radical transparency by publishing complete response letters. News release. US Food and Drug Administration. Published July 10, 2025. Accessed July 10, 2025. https://www.fda.gov/news-events/press-announcements/fda-embraces-radical-transparency-publishing-complete-response-letters
