A Complete Response Letter (CRL) from the U.S. Food and Drug Administration (FDA) communicates to a pharmaceutical company that the review of a drug application is complete, but the application cannot be approved in its current form. When a CRL is issued due to findings related to a third-party manufacturing site inspection, it indicates that the FDA has identified issues with the manufacturing processes, facilities, or quality control at the site where the drug is produced.

In the case of patritumab deruxtecan, a CRL based on a third-party manufacturing site inspection would suggest that the FDA has concerns about how the drug is being manufactured at the third-party facility. The specific nature of these concerns can vary widely, from problems with the facility’s adherence to Good Manufacturing Practices (GMP), issues with data integrity, contamination risks, to deficiencies in the processes used to produce the drug.

The company receiving the CRL is typically required to address the issues identified by the FDA before the drug can be approved. This may involve making changes to the manufacturing process, improving quality control procedures, or even changing the manufacturing site. The company may need to submit additional information or data, conduct new studies, or undergo re-inspection by the FDA to demonstrate that the issues have been resolved.

It’s important to note that a CRL is not the end of the road for a drug’s approval process. Many companies successfully address the concerns raised in CRLs and eventually obtain approval for their products. However, the process can delay getting the drug to market and may require significant resources to resolve the issues to the FDA’s satisfaction.

For the most accurate and up-to-date information regarding patritumab deruxtecan or any specific CRL, it’s best to refer to official FDA announcements, company press releases, and peer-reviewed articles in medical journals.

Source: https://www.merck.com/news/patritumab-deruxtecan-bla-submission-receives-complete-response-letter-from-fda-due-to-inspection-findings-at-third-party-manufacturer/