Emgality (Galcanezumab)
Indications
| Indication | Approved Population | Therapy Type | Status |
|---|---|---|---|
| Preventive treatment of migraine (episodic and chronic) | Adults (≥18 years) | Monotherapy or adjunctive to oral preventives | FDA Approved |
| Treatment of episodic cluster headache | Adults (≥18 years) | Monotherapy; initiated at onset of cluster period | FDA Approved |
Galcanezumab is the only anti-CGRP monoclonal antibody with FDA approval for both migraine prevention and episodic cluster headache treatment. It was first approved for migraine prevention in September 2018 and received approval for episodic cluster headache in June 2019. The 2024 American Headache Society position statement recommends CGRP-targeting therapies as a first-line approach for migraine prevention alongside traditional oral preventives. Clinical trials excluded patients with significant cardiovascular disease, vascular ischemia, or thrombotic events.
Chronic cluster headache: A phase 3 trial (NCT02438826) did not meet its primary endpoint. The reduction in weekly attack frequency was not statistically different from placebo (galcanezumab -5.4 vs placebo -4.6; p=0.334). Evidence quality: Low.
Pediatric episodic migraine (6–17 years): A clinical trial evaluating galcanezumab in pediatric migraine is currently under way. Not yet approved for this population. Evidence quality: Investigational.
Dosing
Adult Migraine Prevention
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum Dose | Notes |
|---|---|---|---|---|
| Episodic migraine — new initiation | 240 mg SC (2 × 120 mg) loading dose | 120 mg SC once monthly | 120 mg/month | Loading dose achieves steady-state after first administration; no titration needed Two consecutive injections at different sites within same body area |
| Chronic migraine — new initiation | 240 mg SC (2 × 120 mg) loading dose | 120 mg SC once monthly | 120 mg/month | Same dosing as episodic migraine; 15% of REGAIN patients used concurrent oral preventive 240 mg monthly dose tested in trials but showed no additional benefit over 120 mg |
| Migraine — treatment-resistant (failed 2–4 prior preventives) | 240 mg SC (2 × 120 mg) loading dose | 120 mg SC once monthly | 120 mg/month | CONQUER trial demonstrated efficacy in this population No dose escalation recommended for non-responders at 120 mg |
Episodic Cluster Headache Treatment
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum Dose | Notes |
|---|---|---|---|---|
| Episodic cluster headache — active cluster period | 300 mg SC (3 × 100 mg) | 300 mg SC monthly until end of cluster period | 300 mg/month | Initiate at onset of cluster period; uses 100 mg/mL prefilled syringes (different from migraine pen) Three consecutive injections at different sites; discontinue when cluster period ends |
The 240 mg loading dose for migraine prevention achieves therapeutic serum concentrations after the very first administration, eliminating the need for the prolonged wait-to-steady-state that would otherwise take approximately 4–5 months with 120 mg monthly dosing alone. This translates to meaningful reductions in migraine frequency from Month 1. If a dose is missed, it should be administered as soon as possible, with subsequent doses rescheduled monthly from the date of the last injection. Injection sites include abdomen, thigh, back of upper arm, or buttocks.
Pharmacology
Mechanism of Action
Galcanezumab is a humanized IgG4/kappa monoclonal antibody that selectively binds to the calcitonin gene-related peptide (CGRP) ligand and prevents it from engaging its receptor. By sequestering CGRP in the peripheral circulation, galcanezumab blocks the vasodilatory, neurogenic inflammatory, and nociceptive signaling cascades that drive migraine pathophysiology. Unlike erenumab, which targets the CGRP receptor, galcanezumab and fremanezumab both target the ligand itself. Galcanezumab binds to CGRP ligand with high affinity and potency, preventing its interaction with the CGRP receptor complex. It is produced by recombinant DNA technology in Chinese hamster ovary cells, consists of two identical kappa light chains and two identical IgG4 heavy chains, and has an overall molecular weight of approximately 147 kDa. The IgG4 subclass confers reduced Fc effector functions compared with IgG1 antibodies, which may contribute to its favorable safety profile.
ADME Profile
| Parameter | Value | Clinical Implication |
|---|---|---|
| Absorption | Tmax ~5 days; linear PK across 1–600 mg; injection site location does not affect absorption | 240 mg loading dose achieves steady-state after first administration; without loading, steady-state requires ~5 months |
| Distribution | V/F ~7.3 L (34% IIV) | Small Vd consistent with monoclonal antibody distribution primarily in vascular and interstitial compartments |
| Metabolism | Catabolic degradation into small peptides and amino acids; not CYP-mediated | No hepatic CYP interactions expected; no dose adjustment for hepatic impairment (dedicated studies not performed) |
| Elimination | CL/F ~0.008 L/h; t½ ~27 days | Long half-life supports once-monthly dosing; body weight has no clinically relevant effect on clearance |
Side Effects
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Injection site reactions (composite) | 18% (vs 13% placebo) | Includes pain, erythema, pruritus, and swelling; generally mild to moderate and resolve within days to 2 weeks |
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Injection site pain | ~7–10% | Most common individual injection site complaint across EVOLVE and REGAIN trials; rates similar to placebo |
| Injection site erythema | ~3–5% | More frequently reported with 240 mg dose than 120 mg in clinical trials; typically self-limiting |
| Injection site pruritus | ~2–4% | Significantly more common with galcanezumab than placebo; more frequent with 240 mg dose |
| Nasopharyngitis | ~5–8% (similar to placebo) | Reported across all treatment groups at similar rates; unlikely drug-related |
| Upper respiratory tract infection | ~3–5% (similar to placebo) | No evidence of increased infection risk with CGRP blockade in pooled safety analyses |
| Constipation | ~1–3% | Reported in real-world studies as one of the more common non-injection-site complaints; CGRP plays a role in gut motility |
| Adverse Effect | Estimated Frequency | Typical Onset | Required Action |
|---|---|---|---|
| Anaphylaxis / Angioedema | Very rare (postmarketing) | Minutes to days post-injection | Permanent discontinuation; epinephrine and emergency care |
| Hypersensitivity reactions (dyspnea, urticaria, rash) | Rare | Days after administration; may be prolonged | Discontinue galcanezumab; initiate appropriate therapy; monitor until resolved |
| Hypertension (new-onset or worsening) | Rare (postmarketing) | Most commonly within 7 days of dose | Monitor BP; initiate antihypertensive if needed; consider discontinuation if inadequately controlled |
| Raynaud’s phenomenon (new-onset or worsening) | Rare (postmarketing) | Median ~71 days after dosing (CGRP mAb class data) | Discontinue galcanezumab; refer for vascular evaluation; most cases resolve after discontinuation |
| Reason for Discontinuation | Incidence | Context |
|---|---|---|
| Injection site reactions | <1% | Most common adverse-event-related reason for discontinuation in controlled trials |
| All-cause adverse events | 1.8% | Comparable across treatment groups in EVOLVE and REGAIN studies; no single serious event pattern |
| Serious adverse events | ≤3.1% | Reported across all treatment groups including placebo in phase 3 studies; no drug-specific SAE pattern |
Allow the prefilled pen or syringe to reach room temperature for 30 minutes before injection. Rotate injection sites among abdomen, thigh, back of upper arm, and buttocks. Do not warm using hot water or a microwave. Injection site reactions are generally mild to moderate in severity and resolve within a few days to 2 weeks. If signs of hypersensitivity (expanding rash, urticaria, dyspnea) develop, this should be differentiated from local injection site reactions and may warrant treatment discontinuation.
Drug Interactions
Galcanezumab is not metabolized by cytochrome P450 enzymes and is unlikely to be affected by drug transport systems. No formal drug interaction studies have been conducted, which is standard practice for monoclonal antibodies. Population pharmacokinetic analyses found no significant impact of concurrent medications on galcanezumab exposure. The clinically relevant considerations below focus on pharmacodynamic rather than pharmacokinetic interactions.
Monitoring
-
Blood Pressure
Baseline, then each visit
Routine Postmarketing reports of new-onset hypertension with CGRP antagonists, most frequently within 7 days of injection. Important in patients with pre-existing hypertension or cardiovascular risk factors. -
Migraine Diary
Continuous; review at 3 months
Routine Track monthly migraine days, headache severity, and acute medication use. Assess treatment response at 3 months; the AHS suggests considering a trial of at least 3 months before concluding non-response. -
Injection Site Assessment
Each injection
Routine Check for persistent erythema, pruritus, or induration. Reactions typically resolve within days to 2 weeks. Distinguish local reactions from systemic hypersensitivity. -
Hypersensitivity Symptoms
Days to weeks post-injection
Trigger-based Reactions can occur days after administration and may be prolonged. Educate patients on signs of urticaria, dyspnea, rash, and facial swelling. Discontinue if serious or severe reaction occurs. -
Raynaud’s Symptoms
Each visit; ongoing patient reporting
Trigger-based Ask about cold-induced color changes or pain in extremities. Discontinue if new symptoms develop and refer for vascular evaluation. Most cases resolve after drug discontinuation. -
Pregnancy Status
Before each dose in women of childbearing age
Routine No adequate human data. The 27-day half-life means drug persists for months after discontinuation. Pregnancy exposure registry available (1-833-464-4724 or www.migrainepregnancyregistry.com).
Contraindications & Cautions
Absolute Contraindications
- Serious hypersensitivity to galcanezumab-gnlm or any excipient (L-histidine, polysorbate 80, sodium chloride). Postmarketing cases of anaphylaxis and angioedema have been reported.
Relative Contraindications (Specialist Input Recommended)
- Active Raynaud’s phenomenon: Postmarketing cases of new-onset and worsening Raynaud’s have been reported with CGRP antagonists. Patients with existing Raynaud’s were excluded from the cluster headache trial. Specialist vascular assessment warranted before initiating treatment.
- Significant cardiovascular disease: Patients with history of MI, stroke, unstable angina, PCI, CABG, DVT, or PE within 6 months of screening were excluded from pivotal trials. CGRP may have cardioprotective properties, and chronic blockade in this population remains uncharacterized.
Use with Caution
- Pre-existing hypertension: Postmarketing reports of new-onset and worsening hypertension. Monitor BP and consider discontinuation if control cannot be achieved.
- Pregnancy and women of childbearing potential: No adequate human data; animal studies showed no teratogenicity. Consider the long half-life (~27 days) when counseling on family planning.
- Elderly patients (≥65 years): Clinical trials did not include sufficient patients ≥65 to determine differential responses; pooled subgroup analyses suggest comparable efficacy and safety up to age 65.
The FDA updated labeling for all CGRP antagonists, including galcanezumab, to include warnings for hypertension and Raynaud’s phenomenon based on postmarketing reports. New-onset or worsening hypertension may occur at any time during treatment, most frequently within 7 days of initiation. Some cases required pharmacological treatment or hospitalization. New-onset or worsening Raynaud’s phenomenon has been reported with monoclonal antibody CGRP antagonists, with a median symptom onset of approximately 71 days. Many cases involved serious outcomes. Most cases resolved after discontinuation of the CGRP antagonist.
Patient Counselling
Purpose of Therapy
Galcanezumab is a preventive treatment that reduces the frequency of migraine attacks or cluster headache episodes. It does not treat an active migraine or headache once it has started; patients should continue their acute treatments (triptans, analgesics, oxygen for cluster headache) as needed. A clinically meaningful response is typically defined as a 50% or greater reduction in monthly migraine days. The full benefit may take up to 3 months to assess, though many patients notice improvement from Month 1 due to the loading dose.
How to Take
Galcanezumab is given as a subcutaneous injection in the abdomen, thigh, back of upper arm, or buttocks. For migraine prevention, the first dose is 240 mg (two injections of 120 mg), followed by 120 mg monthly. For cluster headache, the dose is 300 mg (three injections of 100 mg) at the start of the cluster period, then monthly until the cluster period ends. Allow the device to reach room temperature for 30 minutes before injection. Do not warm using hot water or a microwave. Do not freeze or shake. The solution should appear clear to opalescent, colorless to slightly yellow to slightly brown; do not use if cloudy, discolored, or containing particles. Store refrigerated (2–8°C); may be kept at room temperature (up to 30°C) for up to 7 days.
Sources
- Eli Lilly and Company. EMGALITY (galcanezumab-gnlm) injection, for subcutaneous use: US Prescribing Information. Revised March 2025. FDA Label Primary source for dosing, pharmacokinetics, adverse reactions, contraindications, and March 2025 labeling updates including hypertension and Raynaud’s warnings.
- European Medicines Agency. Emgality (galcanezumab) EPAR — Summary of Product Characteristics. EMA EPAR EU regulatory assessment providing SmPC data and European approval context for adult migraine prevention.
- Stauffer VL, Dodick DW, Zhang Q, Carter JN, Ailani J, Conley RR. Evaluation of galcanezumab for the prevention of episodic migraine: the EVOLVE-1 randomized clinical trial. JAMA Neurol. 2018;75(9):1080–1088. doi:10.1001/jamaneurol.2018.1212 Pivotal 6-month phase 3 trial (Study 1) in episodic migraine (N=858) demonstrating significant MHD reduction with 120 mg monthly.
- Skljarevski V, Matharu M, Millen BA, Ossipov MH, Kim BK, Yang JY. Efficacy and safety of galcanezumab for the prevention of episodic migraine: results of the EVOLVE-2 phase 3 randomized controlled clinical trial. Cephalalgia. 2018;38(8):1442–1454. doi:10.1177/0333102418779543 Second pivotal 6-month phase 3 trial (Study 2) in episodic migraine (N=915) confirming EVOLVE-1 findings across a global population.
- Detke HC, Goadsby PJ, Wang S, Friedman DI, Selzler KJ, Aurora SK. Galcanezumab in chronic migraine: the randomized, double-blind, placebo-controlled REGAIN study. Neurology. 2018;91(24):e2211–e2221. doi:10.1212/WNL.0000000000006640 Pivotal 3-month phase 3 trial (Study 3) in chronic migraine (N=1113) with statistically significant reduction in monthly MHDs.
- Goadsby PJ, Dodick DW, Leone M, et al. Trial of galcanezumab in prevention of episodic cluster headache. N Engl J Med. 2019;381(2):132–141. doi:10.1056/NEJMoa1813440 Pivotal 8-week phase 3 trial (Study 4) in episodic cluster headache (N=106), establishing galcanezumab 300 mg as the first FDA-approved preventive for this condition.
- Mulleners WM, Kim BK, Láinez MJA, et al. Safety and efficacy of galcanezumab in patients for whom previous migraine preventive medication from two to four categories had failed (CONQUER). Lancet Neurol. 2020;19(10):814–825. doi:10.1016/S1474-4422(20)30279-9 Phase 3b trial demonstrating galcanezumab efficacy in treatment-resistant migraine patients with 2–4 prior preventive failures.
- American Headache Society. The American Headache Society Consensus Statement: update on integrating new migraine treatments into clinical practice. Headache. 2021;61(7):1021–1039. doi:10.1111/head.14153 AHS position statement on sequencing of CGRP-targeting therapies within the migraine treatment algorithm.
- Edvinsson L, Haanes KA, Warfvinge K, Krause DN. CGRP as the target of new migraine therapies — successful translation from bench to clinic. Nat Rev Neurol. 2018;14(6):338–350. doi:10.1038/s41582-018-0003-1 Comprehensive review of the CGRP pathway in migraine and the translational journey of anti-CGRP antibodies including galcanezumab.
- Kielbasa W, Helton DL. A new era for migraine: pharmacokinetic and pharmacodynamic insights into monoclonal antibodies with a focus on galcanezumab, an anti-CGRP antibody. Cephalalgia. 2019;39(10):1284–1297. doi:10.1177/0333102419840780 Detailed review of galcanezumab PK/PD properties in the context of CGRP monoclonal antibody pharmacology.
- Kielbasa W, Stratford RE. Population pharmacokinetics of galcanezumab, an anti-CGRP antibody, following subcutaneous dosing to healthy individuals and patients with migraine. J Clin Pharmacol. 2020;60(2):229–239. doi:10.1002/jcph.1511 Population PK model establishing CL/F (0.008 L/h), V/F (7.3 L), and absence of clinically relevant covariate effects.
- Stauffer VL, Sides GD, Engel ER, et al. Effect of age on pharmacokinetics, efficacy, and safety of galcanezumab treatment in adult patients with migraine. J Headache Pain. 2020;21(1):79. doi:10.1186/s10194-020-01148-9 Pooled analysis of six trials confirming that age (up to 65 years) does not affect galcanezumab PK, efficacy, or safety.