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# Rule on Biologic Use of Master Files
- URL: https://www.fdaweb.com/rule-on-biologic-use-of-master-files/
- Published: 2024-02-12T12:00:00.000Z
- Updated: 2026-09-14T14:22:45.000Z
- Author: David McFarland
- Tags: FDA Policy/General, #legacy-id-D5156335

*Federal Register* notice: FDA is issuing a final rule to amend its regulations to address the use of master files by applications licensed under the Public Health Service (PHS) Act. The rule codifies the agency’s existing practice that previously approved applications for certain biological products under the Federal Food, Drug, and Cosmetic Act that have been deemed to be licensed under the PHS Act may continue to reference drug substance, drug substance intermediate, or drug product information contained in a drug master file if such information was being referenced when it was deemed to be licensed. To view the notice, click [here](https://www.govinfo.gov/content/pkg/FR-2024-02-12/pdf/2024-02741.pdf?ref=fdaweb.com).