Necessary adjustment

Changing a pivotal trial’s primary endpoint analysis after the study is under way is usually not a good sign. So when Bristol-Myers Squibb Co. revealed top-line results from the CheckMate -227 trial in a biomarker-defined population that differed from the one it started with, some analysts and media were dubious.

Changing the population in which the endpoint was measured, however, appears to have been the only reasonable move BMS could have made. Emerging science suggests the new biomarker could identify responders who are missed by existing assays...