Sample size calculation in three-arm equivalence trials including a placebo for binary clinical endpoints.

Fei Yu, Shuming Ji, Zaiyun Xiao, Xinyi Zhao, Jie Zhong

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In one paragraph

Article in iScience, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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5 · Who and what money

Authors and funding

5 authors.

Fei YuDepartment of Organization and Personnel, Sichuan Clinical Research for Cancer, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, University of Electronic Science and Technology of China, Chengdu, China.

Shuming JiDepartment of Clinical Research Management, West China Hospital of Sichuan University, Chengdu, China.

Zaiyun XiaoDepartment of Organization and Personnel, Sichuan Clinical Research for Cancer, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, University of Electronic Science and Technology of China, Chengdu, China.

Xinyi ZhaoDepartment of Organization and Personnel, Sichuan Clinical Research for Cancer, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, University of Electronic Science and Technology of China, Chengdu, China.

Jie ZhongDepartment of Organization and Personnel, Sichuan Clinical Research for Cancer, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, University of Electronic Science and Technology of China, Chengdu, China.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

When assessing the equivalence between a generic drug (T) and its innovator drug (R) based on clinical endpoints, three-arm equivalence trials that include a placebo (P) are recommended by regulatory agencies whenever ethically justifiable. In such trials, equivalence of T and R is established only if the equivalence test (T vs. R) and both superiority tests (T vs. P and R vs. P) are simultaneously satisfied. Existing sample size calculation methods have typically considered only the equivalence test and one of the superiority tests (T vs. P), overlooking the other superiority test (R vs. P). We propose two methods for sample size calculation in three-arm equivalence trials with binary endpoints. These methods simultaneously account for the equivalence test based on the ratio of two rates and both superiority tests. Additionally, a grid search approach is proposed to determine the optimal allocation ratio for the sample sizes among the three arms.

Indexed as

Health sciencesMedicine

Identifiers

PMID41660245

DOI10.1016/j.isci.2026.114686

PMCPMC12874132

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.