An approximate approach to sampling size determination for the equivalence hypothesis

Area of Science:

• Biostatistics
• Clinical Trials
• Pharmaceutical Sciences

Background:

• The equivalence hypothesis is crucial for evaluating generic drug products and clinical modalities.
• The two one-sided tests (TOST) procedure is standard for testing equivalence.
• Current sample size formulas for equivalence testing are approximate and can lead to power inaccuracies.

Purpose of the Study:

• To address the lack of an exact sample size formula for the equivalence hypothesis.
• To propose an improved approximate method for sample size determination.
• To enhance the accuracy of sample size calculations in equivalence testing.

Main Methods:

• Developing an approximate sample size calculation method for the equivalence hypothesis.
• Incorporating type II error rate considerations for both one-sided hypotheses.
• Conducting a numerical study to evaluate the proposed method.

Main Results:

• The proposed approximate method offers a more accurate sample size determination than existing formulas.
• Numerical results demonstrate the effectiveness of the approach in balancing statistical power.
• The method provides a practical solution for sample size calculation in equivalence testing.

Conclusions:

• The suggested approximate approach improves sample size determination for the equivalence hypothesis.
• Accurate sample size calculation is vital for reliable generic drug product evaluation.
• This method offers practical guidance for researchers and regulatory bodies.