Sample Size Allocation in Multi-Regional Equivalence Studies


  • Author: Jason J.Z. Liao, Ziji Yu and Yulan Li
  • Date: 15 May 2019
  • Copyright: Image copyright of Patrick Rhodes

In a paper published in Pharmaceutical Statistics, two systematic approaches are proposed for the sample size allocation in a multiregional equivalence trial. A numerical evaluation and a biosimilar trial are used to illustrate the characteristics of the proposed approaches.

The paper is available via the link below and the authors explain their findings in further detail below:

Sample size allocation in multiregional equivalence studies

Jason J.Z. Liao, Ziji Yu and Yulan Li

Pharmaceutical Statistics, Volume 17, Issue 5, September/October 2018, pages 570-577

thumbnail image: Sample Size Allocation in Multi-Regional Equivalence Studies

With the increasing globalization of drug development, the multi-regional clinical trial (MRCT) has gained extensive use. The data from MRCTs could be accepted by regulatory authorities across regions and countries as the primary sources of evidence to support global marketing drug approval simultaneously. The MRCT can speed up patient enrollment and drug approval, and it removes the time gap of the drug approval for different regions and makes the valuable medical treatment available to a broader range of patients simultaneously. However, there are many challenges both operationally and scientifically in conducting a drug development globally. Operationally, the sponsor needs to consider the distinct and sometimes conflicting regulatory requirements. Scientifically, the sponsor needs to design a scientifically sound trial to investigate the overall populations with multiple ethnic factors as well as investigating consistency in treatment effects across populations. One of many important questions to answer for the design of a multi-regional study is how to partition sample size into each individual region. This paper proposed two systematic approaches for the sample size allocation in a multi-regional equivalence trial. A biosimilar trial was used and nicely illustrated the characteristics of the proposed approaches. It is recommended to have early direct communication between the sponsor and regional health authority to reach consensus about the proportion of regional subjects in a global study.

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