Zavegepant

Zavegepant (BHV-3500, formerly BMS-742413) is a third-generation, structurally unique small-molecule antagonist of the calcitonin gene-related peptide (CGRP) receptor, approved by the United States Food and Drug Administration in March 2023 as the first and, as of the most recent monograph revision, only intranasal CGRP receptor antagonist for the acute treatment of migraine with or without aura in adults. The compound exhibits exceptionally high affinity for the human CGRP receptor (Ki = 0.023 nM), placing it among the most potent small-molecule antagonists characterized at this target. Zavegepant is selective for the CLR:RAMP1 heterodimer that constitutes the canonical CGRP receptor, with negligible affinity for the related AM1 (CLR:RAMP2) and AM2 (CLR:RAMP3) receptor subtypes, and acts as a simple competitive antagonist with Schild plot slope not different from unity in human coronary artery preparations.

The compound was originally synthesized at Bristol-Myers Squibb as part of a structure-activity program exploring piperidine-carboxamide scaffolds for CGRP receptor antagonism. The lead molecule incorporated a quinolinone GPCR privileged moiety and a 7-methylindazole D-amino acid to achieve a combination of high binding affinity and improved oxidative stability relative to earlier generation CGRP antagonists. Biohaven Pharmaceuticals licensed the compound from Bristol-Myers Squibb and advanced it through clinical development as BHV-3500, exploiting the molecule's physicochemical properties to enable intranasal formulation, a route that avoids first-pass hepatic metabolism and provides peak plasma concentrations within approximately 30 minutes of administration. The intranasal bioavailability is approximately 5 percent, a value that is sufficient for therapeutic CGRP receptor inhibition (greater than 90 percent receptor occupancy at the 10 mg dose) given the sub-picomolar receptor binding affinity.

Pharmacokinetics following intranasal administration of 10 mg are characterized by rapid absorption (Tmax approximately 30 minutes), moderate plasma protein binding (approximately 90 percent), a large apparent volume of distribution (approximately 1774 liters), an effective half-life of 6.55 hours, and predominantly biliary/fecal elimination (approximately 80 percent of an administered dose), with minor renal excretion (approximately 11 percent). Metabolism is primarily through CYP3A4 with a minor contribution from CYP2D6; approximately 90 percent of circulating drug is the unchanged parent compound. The compound is a substrate of the hepatic uptake transporters OATP1B3 and NTCP, and co-administration with inhibitors of these transporters increases zavegepant exposure approximately 2.3-fold.

Two pivotal randomized, double-blind, placebo-controlled trials (a Phase 2/3 dose-ranging study and a Phase 3 confirmatory study) established the efficacy of intranasal zavegepant 10 mg in the acute treatment of migraine. In the Phase 3 study (N = 1,269), zavegepant achieved pain freedom at two hours in 23.6 percent of participants versus 14.9 percent on placebo (p < 0.001), and freedom from the most bothersome symptom in 39.6 percent versus 31.1 percent (p = 0.001). Pain relief was detectable as early as 15 minutes post-dose and was sustained through 48 hours. A 52-week open-label safety study (N = 603) demonstrated that repeated, as-needed dosing of zavegepant 10 mg nasal spray (up to eight times per month) was well tolerated, with no deaths, no treatment-related serious adverse events, and no cardiovascular adverse events, medication-overuse headache signals, or hepatotoxicity.

The principal adverse events are taste disorders (dysgeusia or ageusia, 18 percent versus 4 percent placebo), nausea (4 percent versus 1 percent), nasal discomfort (3 percent versus 1 percent), and vomiting (2 percent versus less than 1 percent). Post-approval surveillance has additionally identified rare hypertension and Raynaud's phenomenon. The compound is contraindicated in patients with known hypersensitivity to zavegepant. This monograph reviews the chemistry, synthesis, and structure-activity relationships of zavegepant; the CGRP receptor pharmacology and mechanism of action; the comprehensive human pharmacokinetic profile; preclinical and clinical evidence; sourcing and handling; stack interactions; adverse events; and a structured comparative assessment of five CGRP-targeting agents against zavegepant on five competency standards.