Equivalence and superiority testing in regeneration clinical trials

Area of Science:

• Periodontal regeneration
• Clinical trial design
• Biostatistics

Background:

• Equivalence trials assess if a new product has similar therapeutic properties to an established one.
• Superiority trials aim to prove a new therapy is better than an existing one or placebo.
• Regenerative medicine often involves complex clinical trial designs.

Purpose of the Study:

• To investigate sample size requirements for equivalence and superiority clinical trials in periodontal regeneration.
• To compare sample size needs based on different study objectives (equivalence vs. superiority).
• To inform the design of future clinical trials in regenerative medicine.

Main Methods:

• Sample size calculations were performed for both equivalence and superiority trials.
• Assumptions included an alpha of 0.05, 80% power, a 2-group parallel arm study, and equal variances.
• Calculations were conducted for intrabony defects and Class II furcation defects.

Main Results:

• Sample sizes for equivalence and superiority trials were identical when using the same criteria.
• Equivalence trials necessitate much smaller detectable differences, leading to substantially larger sample sizes.
• A 20% difference criterion resulted in sample sizes of 64-127 for equivalence trials, exceeding typical usage.

Conclusions:

• Current sample sizes in periodontal regeneration trials may be insufficient for demonstrating equivalence.
• Equivalence trials in regeneration require careful consideration of sample size to detect clinically meaningful similarities.
• Larger sample sizes are essential for robust equivalence studies in regenerative medicine.