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# CGT Trial Innovative Designs Guidance
- URL: https://www.fdaweb.com/cgt-trial-innovative-designs-guidance/
- Published: 2025-09-24T12:00:00.000Z
- Updated: 2026-09-14T15:22:31.000Z
- Author: David McFarland
- Tags: Biologics, #legacy-id-D5159930

FDA has published a draft guidance, *Innovative Designs for Clinical Trials of Cellular and Gene Therapy Products in Small Populations*, with recommendations for sponsors who are planning clinical trials of cell and gene therapy (CGT) products intended for use in a disease or condition that affects a small population. The [document](ttps://www.fda.gov/media/188892/download) describes FDA requirements and provides considerations for using various clinical trial designs and endpoints to generate clinical evidence to support product licensure.

“This guidance expands on principles described in FDA’s existing guidance documents related to this topic,” it says, “by providing additional recommendations for the planning, design, conduct, and analysis of cell and gene therapy trials to facilitate FDA’s assessment of product effectiveness.”

FDA says it created the draft as part of the agency’s response to the PDUFA 7 commitment to increase efficiency in developing CGT products.

“FDA recognizes the significant challenges in developing drug and biological products for rare diseases, including small population sizes where limited data exist to support regulatory decision-making, sparse natural history knowledge, incompletely understood molecular pathogenetic mechanisms, and molecular and phenotype heterogeneity,” the guidance says. “These development challenges are further compounded by unique considerations for product manufacturing and the generation of nonclinical evidence to support a product’s pharmacology and toxicology profile for CGT products.”

The document contains an Introduction, Background, Innovative Clinical Trial Designs, and Considerations for Participant Selection.