Galcanezumab (Emgality®): A Comprehensive Monograph on a CGRP Antagonist for Headache Disorders

Section 1: Introduction and Drug Profile

1.1. Overview and Therapeutic Class

Galcanezumab represents a significant advancement in the management of debilitating headache disorders, specifically migraine and episodic cluster headache. It is a humanized immunoglobulin G4 (IgG4) monoclonal antibody, a type of biologic therapy developed to specifically target a key molecule in the pathophysiology of these conditions.[1] Developed by Eli Lilly and Company and marketed under the brand name Emgality®, galcanezumab is a cornerstone of a new therapeutic class: calcitonin gene-related peptide (CGRP) antagonists.[4]

The advent of CGRP-targeted monoclonal antibodies marks a paradigm shift in headache medicine. For decades, preventive treatment for migraine relied on repurposed oral medications from other drug classes, such as beta-blockers, antidepressants, and anticonvulsants. While beneficial for some patients, these traditional therapies are often associated with limited efficacy, slow onset of action, and burdensome side effect profiles that lead to poor adherence and high discontinuation rates.[7] Galcanezumab and its contemporaries were engineered based on a sophisticated understanding of migraine neurobiology, offering a targeted approach designed to interrupt a core mechanism of the disease process, thereby improving efficacy and tolerability.[9]

1.2. Nomenclature and Identifiers