Sample Size Calculation for Phase 3 Non-Inferiority Trial of Nebivolol vs. Bisoprolol in China

To calculate the sample size for this non-inferiority clinical trial, we can use the following formula:

n = (2 * Zα/2 + Zβ)^2 * (σ^2 + δ^2) / δ^2

Where: n = sample size Zα/2 = 1.645 for a one-sided 5% significance level Zβ = 1.282 for a power of 90% σ = standard deviation of the mean sitting DBP change δ = non-inferiority margin

Assuming that the standard deviation of the mean sitting DBP change is 7 mmHg and the non-inferiority margin is 2 mmHg, we can calculate the sample size as follows:

n = (2 * 1.645 + 1.282)^2 * (7^2 + 2^2) / 2^2 n = 188 per treatment group

Therefore, a total of 376 patients (188 per treatment group) will be needed for this non-inferiority clinical trial.