A systematic review of noninferiority margins in oncology clinical trials.

Aim: A systematic literature review was conducted to identify and characterize noninferiority margins for relevant end points in oncology clinical trials. Materials & methods: Randomized, controlled, noninferiority trials of patients with cancer were identified in PubMed and Embase. Results: Of 2284 publications identified, 285 oncology noninferiority clinical trials were analyzed. The median noninferiority margin was a hazard ratio of 1.29 (mean: 1.32; range: 1.05-2.05) for studies that reported time-to-event end points (n = 192). The median noninferiority margin was 13.0% (mean: 12.7%; range: 5.0-20.0%) for studies that reported response end points as absolute rate differences (n = 31). Conclusion: Although there was consistency in the noninferiority margins' scale, variability was evident in noninferiority margins across trials. Increased transparency may improve consistency in noninferiority margin application in oncology clinical trials.