FDA CRLs Reveal a Pattern: Biologic Control Strategy Issues Drive Delays and Rejections

In July 2025, the FDA for the first time made 202 Complete Response Letters (CRLs) public. A subsequent release in September added 89 more CRLs; however, these were heavily redacted as the associated applications remain under review, limiting the insights that could be derived. The July release included CRLs issued between 2020 and 2024 for applications that have since achieved approval. Of the 202 CRLs published, 46 were associated with Biologics License Applications (BLAs), remainder 156 were associated with New Drug Applications (NDAs). Analysis of these 46 BLA- related CRLs revealed that 11 cited deficiencies in control strategy, representing the most common quality-related theme identified in this data set.