Optimal sample size allocation for two-arm superiority and non-inferiority trials with binary endpoints.

Area of Science:

• Clinical Trials
• Biostatistics
• Medical Research

Background:

• Clinical trial sample size is critical for study power and resource management.
• Sample size allocation between groups impacts overall trial size.
• Ethical and economic considerations necessitate avoiding unnecessarily large sample sizes.

Purpose of the Study:

• To determine the optimal sample size allocation ratio for two-arm superiority and non-inferiority trials with binary endpoints.
• To minimize the total sample size required while keeping other parameters constant.
• To compare the efficiency of optimal allocation versus equal allocation.

Main Methods:

• Extensive computations were performed across a wide range of scenarios.
• The focus was on two-arm trials with binary endpoints.
• The study analyzed superiority and non-inferiority trial designs.

Main Results:

• The optimal sample size allocation ratio can differ significantly from equal allocation in both superiority and non-inferiority trials.
• Deviations from equal allocation were explored for binary endpoints.
• Calculations were conducted for various trial parameters and scenarios.

Conclusions:

• Optimal sample size allocation may not always be equal group sizes for binary endpoint trials.
• While optimal allocation can reduce sample size, the savings compared to equal allocation are generally modest.
• The findings provide guidance for efficient clinical trial design.