Hierarchical dynamic allocation procedures based on modified Zelen's approach in multiregional studies with unequal...

Area of Science:

• Biostatistics
• Clinical Trial Design
• Multicenter Studies

Background:

• The modified Zelen's approach ensures balanced treatment assignments in multicenter studies with equal allocation.
• Existing methods may not adequately address complex allocation schemes or balance across multiple covariates.

Purpose of the Study:

• To describe novel hierarchical balancing procedures for equal allocation to more than two treatment arms.
• To present unequal allocation expansions incorporating the modified Zelen's approach at the center level.
• To evaluate the balancing properties of these procedures in a multiregional clinical trial simulation.

Main Methods:

• Development of hierarchical balancing procedures for multi-arm trials.
• Expansion of procedures for unequal allocation ratios (e.g., 1:2).
• Simulation study to assess balancing properties within regions and for other covariates.

Main Results:

• The described hierarchical procedures demonstrate effective balancing of treatment assignments.
• Simulations confirm the utility of the methods in complex trial designs, including multiregional studies.
• The approach successfully balances covariates within regions and across the study.

Conclusions:

• Hierarchical balancing procedures offer robust methods for complex clinical trial designs.
• These procedures, incorporating modified Zelen's approach, enhance treatment assignment balance in multicenter and multiregional trials.
• The findings support the application of these methods for improved clinical trial efficiency and validity.