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Updated: Apr 7, 2026

Quadruple-Checkerboard: A Modification of the Three-Dimensional Checkerboard for Studying Drug Combinations
Published on: July 24, 2021
A two-dimensional biased coin design for dual-agent dose-finding trials
1Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, MI, USA zcs@umich.edu.
This study introduces a new nonparametric design for Phase I clinical trials to find the best combination of two cancer drugs. The adaptive biased coin design improves patient safety and accurately identifies the maximum tolerated combination.
Area of Science:
- Clinical Trial Design
- Pharmacometrics
- Biostatistics
Background:
- Limited efficacy of single agents necessitates combination therapies.
- Growing need for Phase I clinical trial designs to identify optimal drug combinations.
- Existing parametric designs for combination trials may be over- or under-parameterized.
Purpose of the Study:
- To develop a novel, easily understandable, and implementable nonparametric approach for dual-agent dose-finding trials.
- To address limitations of existing parametric designs in combination therapy trials.
Main Methods:
- Proposed a two-stage adaptive biased coin design for dual-agent dose-finding.
- Extended single-agent trial methods to combination settings.
- Modified the biased coin design for application in two distinct trial stages.
Main Results:
- The proposed nonparametric design performed well in simulations across various scenarios.
- Successfully identified the maximum tolerated combination and allocated patients effectively.
- Outperformed competing parametric approaches in key operating characteristics.
Conclusions:
- The design offers favorable statistical properties and promotes patient safety.
- Requires careful consideration of stopping rules and sample size distribution between stages.
- Efficacy is not used in dose assignment or defining the maximum tolerated combination.
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