Therapeutic agents that block the calcitonin gene–related peptide (CGRP) signaling pathway are a highly anticipated and promising new drug class for migraine therapy, especially after reports that small-molecule CGRP-receptor antagonists are efficacious for both acute migraine treatment and migraine prevention. Using XenoMouse technology, we successfully generated AMG 334, a fully human monoclonal antibody against the CGRP receptor. Here we show that AMG 334 competes with [125I]-CGRP binding to the human CGRP receptor, with a Ki of 0.02 nM. AMG 334 fully inhibited CGRP-stimulated cAMP production with an IC50 of 2.3 nM in cell-based functional assays (human CGRP receptor) and was 5000-fold more selective for the CGRP receptor than other human calcitonin family receptors, including adrenomedullin, calcitonin, and amylin receptors. Read More →