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# Guide on Gene Therapy Orphan Drugs
- URL: https://www.fdaweb.com/guide-on-gene-therapy-orphan-drugs/
- Published: 2021-10-01T12:00:00.000Z
- Updated: 2026-09-14T17:17:06.000Z
- Author: David McFarland
- Tags: FDA Policy/General, #legacy-id-D5150271

*Federal Register* notice: FDA has made available a final guidance entitled *Interpreting Sameness of Gene Therapy Products Under the Orphan Drug Regulations*. The document provides FDA’s current thinking on certain criteria that help determine gene therapy sameness for the purposes of orphan-drug designation and orphan-drug exclusivity. To view the notice, click [here](https://www.govinfo.gov/content/pkg/FR-2021-09-30/pdf/2021-21324.pdf?ref=fdaweb.com).