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# Groups Praise FDA Expansion Cohorts Guidance
- URL: https://www.fdaweb.com/groups-praise-fda-expansion-cohorts-guidance/
- Published: 2018-10-17T12:00:00.000Z
- Updated: 2026-09-15T00:38:42.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5142600

Pfizer says an FDA draft guidance on use of expansion cohorts in first-in-human clinical trials to expedite development of cancer drugs and biologics will be helpful to sponsors. The company [expresses](https://www.regulations.gov/document?D=FDA-2018-D-2777-0019&ref=fdaweb.com) concern that the draft is limited to oncology products. “Pfizer believes there may be other therapeutic contexts, such as high unmet need autoimmune disease settings, in which a similar approach could be used,” the comment letter says, “and we would therefore encourage the agency to consider broadening the scope of the draft guidance.” The letter also says the company believes that smaller trials with a limited number of expansion cohorts intended to evaluate proof of concept should fall outside the guidance scope.

The American Society of Clinical Oncology (ASCO) [says](https://www.regulations.gov/document?D=FDA-2018-D-2777-0012&ref=fdaweb.com) it “supports FDA’s initial thinking and guidance presented in this draft proposal on the design and statistical considerations, for multiple expansion cohort trials. ASCO supports the agency’s proposal that each expansion cohort should be designed with a robust rationale, objective, endpoints, and analysis plan. We believe expansion cohort trials make clinical trials easier for sites and patients due to having one protocol with multiple cohorts rather than multiple protocols.” The society suggests some areas for clarification and further discussion.

The Biotechnology Innovation Organization (BIO) [says](https://www.regulations.gov/document?D=FDA-2018-D-2777-0016&ref=fdaweb.com) it “welcomes FDA’s efforts to provide clear guidance on the regulatory and scientific framework for product developers designing and conducting adaptive trial designs in which different aspects of a drug can be assessed in a single clinical trial while enrolling the minimum number of study participants necessary to obtain this information.” BIO provides both general and specific line-by-line comments.

The International Drug Development Institute [says](https://www.regulations.gov/document?D=FDA-2018-D-2777-0008&ref=fdaweb.com) it commends FDA for a draft guidance that is “well-crafted and quite comprehensive with regard to issues that may arise when designing or conducting such studies.” The institute says it wants to emphasize the need to consider randomization whenever feasible in expansion cohorts, even though randomization has rarely been used until now in this setting. “Our view is that the use of a randomized control group should be considered when designing any clinical trial,” the comment letter says, “including an expansion cohort, in order to produce an unbiased assessment of a drug’s efficacy.”

AstraZeneca’s comment [letter](https://www.regulations.gov/document?D=FDA-2018-D-2777-0006&ref=fdaweb.com) provided line-by-line comments.