Last updated 10 August 2025 - best viewed on desktop
On July 10, 2025, the U.S. Food and Drug Administration (FDA) published 202 documents containing Complete Response Letters (CRLs). CRLs are formal communications the FDA sends to drug or biologic sponsor when an application is not approved in its current form.
The initial release included CRLs issued between 2020 and 2024. The publication of CRLs is part of a broader FDA initiative to increase transparency in the drug review process. The letters are redacted to protect confidential commercial information but still provide insight into common reasons for non-approval.
This webpage has been created after reviewing all the documents within the dataset and analysing the Key issues within each Letter published by the FDA.
Documents in FDA CRL Dataset Letters within thedocuments Complete Response Letters Rescind Complete Response Letter: Tentative Approval Letter: Refusal To File Letter: Acknowledge Incomplete Response Letter: Provisional Determination: Corrected Provisional Determination: ‘Applicant’ refers to the company names to which the CRL(s) were addressed. Subsidiary and parent company names have not been consolidated.
Only Key Issues that were identified as preventing the application(s) from being approved have been captured. Issues not preventing the approval of the application(s) have not been captured; these often related to Labelling, Prescribing Information, Regulatory Label, Safety Update, or Proprietary name.
The information and data below provides a closer look at the number of times each Key Issue was citied within the released dataset and the reasons relating to the issuance of the CRL.
Facility Inspection refers to a required FDA evaluation of the manufacturing and/or testing sites listed in the application.
Number of CRLs citing ‘Facility Inspection’ as a contributing issue:
% of all CRLs citing ‘Facility Inspection’ as a contributing issue:
Facility Inspection: Reasons
Clinical refers to deficiencies or issues related to the human clinical trial data that are needed to demonstrate a drugs efficacy and safety for its intended use.
Number of CRLs citing ‘Clinical’ as a contributing issue:
% of all CRLs citing ‘Clinical’ as a contributing issue:
Further clinical studies required due to insufficient evidence for effectiveness, additional safety data requirements and/or requirement for further confirmatory evidence.
Clinical Pharmacology refers to how a drug is absorbed, distributed, metabolized, and excreted, as well as its effects on the body, which underpin dosing decisions, safety profiles, and appropriate labeling.
Number of CRLs citing ‘Clinical Pharmacology’ as a contributing issue:
% of all CRLs citing ‘Clinical Pharmacology’ as a contributing issue:
Additional information/clarification and or further data was required in all instances that Clinical Pharmacology issues was cited within a CRL.
Nonclinical refers to preclinical studies that assess a drug’s safety and/or biological activity before or alongside human clinical trials.
Number of CRLs citing ‘Nonclinical’ as a contributing issue:
% of all CRLs citing ‘Nonclinical’ as a contributing issue:
Additional information/clarification and or further data required in all instances that Nonclinical issues was cited within a CRL. CRL(s) had Nonclinical sections that were fully redacted and was unable to identify remedial actions requested by the FDA. Nonclinical Study Required
Specific reasons relating to the type of nonclinical studies required has not been collated within this analysis
Product Quality refers to the manufacturing and control data that demonstrates that the drug product can be reliably produced with consistent identity, strength, purity, and quality.
Number of CRLs citing ‘Product Quality’ as a contributing issue:
% of all CRLs citing ‘Product Quality’ as a contributing issue:
CRLs had Product Quality sections that were fully redacted and was unable to identify remedial actions requested by the FDA. Device refers to a medical device or component of a product whose design, function, usability, or compliance which must meet FDA standards to ensure the device is suitable for its intended use.
Number of CRLs citing ‘Device’ as a contributing issue:
% of all CRLs citing ‘Device’ as a contributing issue:
Additional information/clarification and or further data required in instances that Device issues was cited within a CRL. In 2 CRLs for 1 NDA, the NDA was not approved as the proposed device in the drug-device combination product was not approved. Human factors refers to the study and application of how people interact with a drug, device, or combination product, especially in terms of usability, safety, and effectiveness.
Number of CRLs citing ‘Human Factors’ as a contributing issue:
% of all CRLs citing ‘Human Factors’ as a contributing issue:
Additional information/clarification and or further data was required in all instances that Human factors study issues was cited within a CRL.
Patent certification is a mandatory legal declaration to address how the applicant intends to handle existing patents protecting drugs or uses they are relying on for FDA approval. It ensures compliance with intellectual property laws while allowing streamlined drug development.
Number of CRLs citing ‘Patent Certification’ as a contributing issue:
% of all CRLs citing ‘Patent Certification’ as a contributing issue:
Pediatric Research Equity Act (PREA) gives the FDA the authority to require pediatric studies for certain drugs and biological products.
Number of CRLs citing ‘PREA Requirements’ as a contributing issue:
% of all CRLs citing ‘PREA Requirements’ as a contributing issue:
A Risk Evaluation and Mitigation Strategy (REMS) is a drug safety program that the FDA can require for certain medications with serious safety concerns to help ensure the benefits of the medication outweigh its risks. REMS are designed to reinforce medication use behaviors and actions that support the appropriate use of that medication.
Number of CRLs citing ‘REMS Requirements’ as a contributing issue:
% of all CRLs citing ‘REMS Requirements’ as a contributing issue:
Post-marketing Requirements
Post-marketing Requirements are commitments that a sponsor must agree to after product approval to gather further safety, efficacy, or use-related data. This may include further clinical studies, monitoring or further data analysis.
Number of CRLs citing ‘Post-marketing Requirements’ as a contributing issue:
% of all CRLs citing ‘Post-Marketing Requirements’ as a contributing issue:
Number of CRLs with Other issues than those stated above as contributing issue(s):
% of all CRLs with Other issues than those stated above as contributing issue(s):
Additional Chemistry Manufacturing and Controls (CMC) information/clarification needed: Additional regulatory information/clarification needed: (Redacted ) Quality system deficiencies found that require amendment: Company unable to submit labelling during review cycle: Reference product still under period of exclusivity:
Citation
PRV Watch. (2025). FDA Complete Response Letter Dashboard. Website: https://www.prvwatch.com
This webpage has been compiled from manually reviewing the hundreds of Complete Response Letters released by the U.S. Food and Drug Administrations (FDA). There were variations across the letters on the titles/phrasing of each Key Issue topic, to enable data analysis I have harmonized the titles where there was variance.
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