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# Mallinckrodt Stannsoporfin Complete Response Letter
- URL: https://www.fdaweb.com/mallinckrodt-stannsoporfin-complete-response-letter/
- Published: 2018-08-22T12:00:00.000Z
- Updated: 2026-09-15T00:27:27.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5142176

FDA has issued a complete response letter (CRL) for Mallinckrodt’s stannsoporfin, a heme oxygenase inhibitor under investigation for treating newborns with indicators of hemolysis who are at risk of developing severe jaundice. The company [says](https://www.prnewswire.com/news-releases/mallinckrodt-confirms-receipt-of-stannsoporfin-complete-response-letter-300700500.html?ref=fdaweb.com) the agency provided guidance about areas of further evaluation for resubmitting the stannsoporfin NDA. Company officials said the CRL was not unexpected given the outcome at a recent advisory committee meeting and said they will request a meeting with agency officials in the coming months to discuss potential paths forward.