Related Experiment Video
Updated: Jun 4, 2026

Frequency and Distribution of Crossovers in Caenorhabditis elegans Meiosis by SNP Genotyping using Real-time PCR
Published on: July 11, 2025
Additional results for 'Sequential design approaches for bioequivalence studies with crossover designs'
Timothy H Montague1, Diane Potvin, Charles E Diliberti
1GlaxoSmithKline, Inc., King of Prussia, PA, USA.
This study evaluates two-stage crossover bioequivalence (BE) designs for sample size reestimation. Method D is recommended when assuming a geometric mean ratio (GMR) of 0.90 to maintain acceptable Type I error rates.
Area of Science:
- Biostatistics
- Pharmacokinetics
- Drug Development
Background:
- Bioequivalence (BE) studies are crucial for generic drug approval.
- Two-stage crossover designs allow for sample size adjustments.
- Previous work focused on a geometric mean ratio (GMR) of 0.95.
Purpose of the Study:
- To evaluate sequential methods for two-stage BE studies with an assumed GMR of 0.90.
- To assess the impact of changing the assumed GMR on Type I error rates.
- To recommend appropriate methods for GMR = 0.90 scenarios.
Main Methods:
- Analysis of sequential methods for two-stage crossover bioequivalence designs.
- Reestimation of second-stage sample size based on first-stage variance.
- Evaluation of Type I error rates under different assumed GMRs (0.95 vs. 0.90).
Main Results:
- Two previously recommended methods showed unacceptable increases in Type I error rates when the assumed GMR was changed to 0.90.
- Method D maintained acceptable Type I error rates for GMR = 0.90.
Conclusions:
- The choice of method in two-stage BE studies is critical when the assumed GMR deviates from 0.95.
- Method D is the recommended approach for sponsors assuming a GMR of 0.90 to ensure study validity.
More Related Videos
08:58Efficient Sampling of Genetically Encoded Biosensor Design Space Enabled with a Design of Experiments and Automation Workflow
Published on: October 17, 2025
20:24Characterization of Complex Systems Using the Design of Experiments Approach: Transient Protein Expression in Tobacco as a Case Study
Published on: January 31, 2014
Related Concept Videos
Bioequivalence Experimental Study Designs: Repeated Measures, Cross-Over, Carry-Over, and Latin Square Designs
Crossover Experiments
Crossover designs are performed even with smaller sample sizes since the samples can act as their controls. These are better than simple randomized trials since patients are exposed to all the treatments.
Bioequivalence Experimental Study Designs: Completely Randomized and Randomized Block Designs
Bioequivalence Data: Statistical Interpretation
Bioavailability Study Design: Single Versus Multiple Dose Studies
Bioequivalence studies: Biowaivers