Progress and promise of pharmacodynamic biomarkers: novel strategies and assay considerations in drug development.

Pharmacodynamic (PD) biomarkers provide crucial insights into a drug's mechanism of action (MoA) and efficacy by measuring its effects on biological targets within an organism. PD biomarkers can be proximal (e.g. receptor occupancy, enzyme inhibition) or distal (e.g. downstream pathway modulation) to the biological target. In drug development, PD biomarkers are essential for monitoring patient response, assessing therapeutic efficacy, optimizing dosage strategies, and streamlining the drug development process by informing go/no-go decisions. In personalized medicine, PD biomarkers enable tailored treatments based on individual responses, enhancing both effectiveness and safety. Sound bioanalytical strategies and rigorous assay validation practices are key for successful integration of PD biomarkers into clinical trials. This paper outlines the bioanalytical and assay considerations for developing and validating informative PD biomarker assays and their use in drug development.