Discussion on "Adaptive enrichment designs with a continuous biomarker" by Nigel Stallard. Issue 1 (15th March 2022)

• Record Type: Journal Article
• Authors: Flournoy, Nancy; Tarima, Sergey
• Is Part Of: Biometrics. Volume 79:Issue 1(2023)
• Page Start: 31
• Page End: 35
• Publication Date: 2022-03-15
• Subjects: adaptive likelihood ratio tests -- informative adaptation -- likelihood estimation -- threshold selection; Biometry -- Periodicals; 570.15195
• DOI: 10.1111/biom.13641
• Languages: English
• ISSNs: 0006-341X

Abstract

Abstract: We congratulate Dr. Nigel Stallard on his stimulating paper on adaptive enrichment designs with a continuous biomarker . Dr. Stallard details a framework for a large and interesting class of enrichment procedures. His work has motivated us to offer some thoughts in response. Dr. Stallard's strategy is to use the maximum of a test statistic over a set of possible threshold values to define the enriched population to be sampled in a second stage. This reminds us of procedures for identifying a change point, a biomarker value beyond which the effect of treatment is increased. For simplicity we focus our comments on Dr. Stallard's Rule 1 for selecting the second‐stage sampling threshold. Using this rule, we present the likelihood ratio approach for adaptive testing and compare it to Dr. Stallard's approach for a few scenarios.