Translational Pharmacodynamics of Calcitonin Gene-Related Peptide Monoclonal Antibody LY2951742 in a Capsaicin-Induced Dermal Blood Flow Model

LY2951742, a monoclonal antibody targeting calcitonin gene-related peptide (CGRP), is being developed for migraine prevention and osteoarthritis pain. To support the clinical development of LY2951742, capsaicin-induced dermal blood flow (DBF) was used as a target engagement biomarker to assess CGRP activity in nonhuman primates and healthy volunteers. Inhibition of capsaicin-induced DBF in nonhuman primates, measured with laser Doppler imaging, was dose dependent and sustained for at least 29 days after a single intravenous injection of the CGRP antibody. This information was used to generate a pharmacokinetic/pharmacodynamic model, which correctly predicted inhibition of capsaicin-induced DBF in humans starting at a single subcutaneous 5-mg dose. As expected, the degree of inhibition in capsaicin-induced DBF increased with higher LY2951742 plasma concentrations. Utilization of this pharmacodynamic biomarker with pharmacokinetic data collected in phase I studies provided the dose-response relationship that assisted in dose selection for the phase II clinical development of LY2951742.