From Afterthought to Design Driver

Over the past decade, biomarkers have moved from the margins of oncology clinical trials into their structural core. Where they were once treated as exploratory endpoints or optional correlative work, they now shape who is eligible for a study, how early activity is interpreted and which dose ultimately reaches clinical practice. In the era of precision oncology, trials increasingly ask whether a drug works in a biologically defined subgroup, using biomarkers as the organising framework for design and analysis.

From the perspective of an early-phase oncologist, the most important shift is not simply that biomarkers are used more often, but that they are integrated earlier and more deliberately into development. When a biomarker and a drug are conceived and developed together, sometimes even biomarker first, compound second, the odds of selecting the right patients, demonstrating proof of mechanism and identifying a biologically appropriate dose are significantly better.