The incorporation of biomarkers into clinical drug development is becoming more common. Often, one or more biomarkers are motivated by the drug mechanism of action. However, the best strategy to balance speed and confidence is generally uncertain. In the past, biomarkers were mostly assessed in an exploratory context, perhaps dozens at a time. Increasingly, there is interest in effectively incorporating at least a single biomarker into development strategy so as to impact pivotal studies as emerging data warrant. Recent developments in the area will be discussed including an overview of some publications and a submission example.