Ajovy (Fremanezumab)
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 |
| Preventive treatment of episodic migraine | Pediatric patients 6–17 years, ≥45 kg | Monotherapy or adjunctive | FDA Approved |
Fremanezumab is approved for the preventive treatment of migraine in adults regardless of migraine subtype (episodic or chronic), with two flexible dosing regimens. It received an expanded indication in August 2025 for pediatric episodic migraine in patients aged 6 to 17 years who weigh at least 45 kg, making it the first anti-CGRP monoclonal antibody approved for this pediatric population. Clinical trials excluded patients with significant cardiovascular disease, vascular ischemia, or thrombotic events. The American Headache Society consensus statement recommends consideration of CGRP-targeting monoclonal antibodies in patients who have failed or are intolerant to at least two conventional oral preventive medications.
Episodic cluster headache: A phase III trial (ENFORCE, NCT03107052) was conducted but did not meet its primary endpoint. The chronic cluster headache trial was halted for futility in 2018. Evidence quality: Low.
Persistent post-traumatic headache: A phase II trial did not demonstrate statistical separation from placebo for the primary endpoint. Evidence quality: Low.
Dosing
Adult Migraine Prevention
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum Dose | Notes |
|---|---|---|---|---|
| Episodic migraine — monthly regimen | 225 mg SC | 225 mg SC once monthly | 225 mg/month | No loading dose needed; inject in abdomen, thigh, or upper arm Single prefilled syringe or autoinjector per dose |
| Episodic migraine — quarterly regimen | 675 mg SC (3 × 225 mg) | 675 mg SC every 3 months | 675 mg/quarter | Three consecutive injections at different sites within the same body area Useful for patients who prefer less frequent dosing |
| Chronic migraine — monthly regimen (per HALO CM trial protocol) | 675 mg SC (3 × 225 mg) loading dose | 225 mg SC once monthly | 225 mg/month (after loading) | The FDA label does not specify a separate chronic migraine regimen; however, the pivotal HALO CM trial used a 675 mg loading dose on Day 1 before monthly 225 mg maintenance Many headache specialists adopt this loading strategy for chronic migraine based on trial design |
| Chronic migraine — quarterly regimen | 675 mg SC (3 × 225 mg) | 675 mg SC every 3 months | 675 mg/quarter | No separate loading dose with quarterly schedule Similar efficacy to monthly regimen in HALO CM trial |
| Switching between monthly and quarterly | New regimen dose | Per new regimen | Per new regimen | Administer first dose of new regimen on the next scheduled date No washout period required |
Pediatric Migraine Prevention (6–17 Years, ≥45 kg)
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum Dose | Notes |
|---|---|---|---|---|
| Episodic migraine — monthly only | 225 mg SC | 225 mg SC once monthly | 225 mg/month | Only monthly dosing is approved for pediatric patients Ages 6–12: must be administered by HCP or adult caregiver; ages 13+: can self-administer |
Unlike many oral migraine preventives (topiramate, valproate, amitriptyline), fremanezumab requires no dose titration. Full therapeutic doses are given from Day 1, and meaningful reductions in migraine frequency are often apparent within the first month of treatment. The long half-life (~31 days) supports both monthly and quarterly administration. If a dose is missed, it should be administered as soon as possible, with subsequent doses rescheduled from the date of the missed dose.
Pharmacology
Mechanism of Action
Fremanezumab is a fully humanized IgG2Δa/kappa monoclonal antibody that selectively binds to both alpha and beta isoforms of the calcitonin gene-related peptide (CGRP) ligand. By sequestering CGRP, it prevents the peptide from interacting with its receptor, thereby blocking the downstream vasodilatory and nociceptive signaling pathways central to migraine pathophysiology. Notably, fremanezumab targets the CGRP ligand itself rather than the CGRP receptor (which is the target of erenumab), providing a mechanistically distinct approach within this drug class. Preclinical data indicate that fremanezumab selectively inhibits activation of thinly myelinated A-delta meningeal nociceptors while sparing unmyelinated C-fibers, which may contribute to its selective effect on the migraine pain pathway. The antibody is produced by recombinant DNA technology in Chinese hamster ovary cells, consists of 1324 amino acids, and has a molecular weight of approximately 148 kDa.
ADME Profile
| Parameter | Value | Clinical Implication |
|---|---|---|
| Absorption | Bioavailability ~66%; Tmax 5–7 days; dose-proportional PK (225–900 mg) | Slow absorption typical for SC monoclonal antibodies; steady state reached by ~6 months with monthly dosing |
| Distribution | Apparent Vd ~6 L; accumulation ratio ~2.3 (monthly) or ~1.2 (quarterly) | Small Vd indicates drug remains primarily in the vascular and interstitial compartments with minimal tissue penetration |
| Metabolism | Enzymatic proteolysis to small peptides and amino acids; not CYP-mediated | No hepatic CYP interactions; no dose adjustment for mild-moderate hepatic impairment (severe not studied) |
| Elimination | CL ~0.141 L/day; t½ ~31 days | Long half-life supports monthly or quarterly dosing; residual drug effect persists for months after discontinuation |
Side Effects
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Injection site reactions (composite) | 43–45% (vs 38% placebo) | Includes pain, induration, erythema, and ecchymosis; frequency highest with the first dose and decreases over subsequent injections |
| Injection site pain | 20–24% (vs 20–22% placebo) | Usually mild and transient; allowing product to reach room temperature before injection may reduce pain |
| Injection site induration | 15–18% (vs 13% placebo) | Typically resolves within hours to days; rotating injection sites is recommended |
| Injection site erythema | 15–16% (vs 12% placebo) | Generally mild; monitor for signs of expanding erythema suggestive of hypersensitivity |
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Injection site ecchymosis | ~3–5% | More common in patients on concurrent anticoagulants or antiplatelets; no clinical sequelae |
| Hypersensitivity reactions (rash, pruritus, urticaria) | ~1–2% | Most reactions mild-moderate; onset from within hours to one month after administration; some required corticosteroid treatment |
| Nasopharyngitis | ~3–6% (similar to placebo) | Not clearly drug-related given similar placebo rates; reported in pooled phase 3 safety analyses |
| Adverse Effect | Estimated Frequency | Typical Onset | Required Action |
|---|---|---|---|
| Anaphylaxis / Angioedema | Very rare | Minutes to hours post-injection | Permanent discontinuation; epinephrine and emergency care; report to manufacturer |
| Hypertension (new-onset or worsening) | Rare (postmarketing) | Most commonly within 7 days of dose; can occur any time during treatment | Monitor BP; initiate antihypertensive therapy if needed; consider discontinuation if BP inadequately controlled |
| Raynaud’s phenomenon (new-onset or worsening) | Rare (postmarketing) | Median ~71 days after dosing (CGRP mAb class data) | Discontinue fremanezumab; refer for vascular evaluation; most cases resolve after drug discontinuation |
| Reason for Discontinuation | Incidence | Context |
|---|---|---|
| Injection site reactions | ~1% | Most common reason for treatment discontinuation in controlled trials |
| Hypersensitivity | <1% | Some patients requiring corticosteroid treatment opted to discontinue |
| All-cause serious adverse events | ~1.2% (vs 1.6% placebo) | No pattern of specific serious events; rate comparable to placebo across pooled analyses |
Allow the prefilled syringe or autoinjector to sit at room temperature for 30 minutes before injection. Rotate injection sites among abdomen, thigh, and upper arm. Injection site reactions are most frequent with the initial dose and generally diminish over subsequent administrations. If persistent induration or expanding erythema develops beyond the immediate injection area, evaluate for hypersensitivity rather than simple local reaction.
Drug Interactions
Fremanezumab is a monoclonal antibody degraded by enzymatic proteolysis and is not metabolized by cytochrome P450 enzymes. Pharmacokinetic drug–drug interactions are therefore unlikely. Population pharmacokinetic analyses confirmed that acute migraine treatments (triptans, analgesics, ergots) and concurrent preventive medications did not influence fremanezumab exposure. No formal drug interaction studies have been conducted, which is standard practice for monoclonal antibodies. The clinically relevant considerations below relate to pharmacodynamic rather than pharmacokinetic effects.
Monitoring
-
Blood Pressure
Baseline, then each visit
Routine Postmarketing reports of new-onset hypertension, most within 7 days of injection. Particularly important in patients with pre-existing hypertension or cardiovascular risk factors. Consider discontinuation if BP rises and no alternative cause identified. -
Migraine Diary
Continuous; review at 3 months
Routine Track monthly migraine days, headache severity, and acute medication use. Assess treatment response at 3 months (12 weeks); consider discontinuation if no meaningful reduction in migraine frequency or severity. -
Injection Site Assessment
Each injection
Routine Check for persistent induration, expanding erythema, or signs of cellulitis. Educate patients to distinguish mild local reactions from hypersensitivity. Most reactions decrease over time with continued use. -
Hypersensitivity Symptoms
Within hours to 1 month post-dose
Trigger-based Instruct patients on signs of allergic reactions including urticaria, facial swelling, dyspnea. Reactions can occur up to one month post-injection. Consider discontinuation and appropriate therapy if hypersensitivity develops. -
Raynaud’s Symptoms
Each visit; ongoing patient reporting
Trigger-based Ask about cold-induced color changes or pain in fingers/toes. Especially important in patients with a history of Raynaud’s phenomenon. Discontinue if new symptoms develop and refer for evaluation. -
Pregnancy Status
Before each dose in women of childbearing age
Routine No adequate human data. The ~31-day half-life means drug persists long after discontinuation. Encourage enrollment in the pregnancy exposure registry (1-833-927-2605) if pregnancy occurs during treatment.
Contraindications & Cautions
Absolute Contraindications
- Serious hypersensitivity to fremanezumab-vfrm or any excipient (EDTA, L-histidine, polysorbate-80, sucrose). Postmarketing cases of anaphylaxis and angioedema have been reported.
Relative Contraindications (Specialist Input Recommended)
- Active Raynaud’s phenomenon: CGRP plays a role in peripheral vasodilation; postmarketing cases of new-onset and worsening Raynaud’s have been reported with CGRP antagonists. Specialist consultation is warranted before initiating treatment.
- Significant cardiovascular disease: Patients with major cardiovascular events (MI, stroke, TIA, DVT, PE) were excluded from pivotal trials. CGRP may have cardioprotective properties, and chronic blockade in this population is not well characterized.
- Severe hepatic impairment (Child-Pugh C): Pharmacokinetics have not been studied in this population.
Use with Caution
- Pre-existing hypertension: Postmarketing reports of new-onset and worsening hypertension. Monitor blood pressure and assess whether discontinuation is warranted if adequate control cannot be achieved.
- Pregnancy and women of childbearing potential: No adequate human data. Animal reproduction studies did not show teratogenicity, but the long half-life should be considered for family planning purposes.
- Elderly patients (≥65 years): Limited trial data in this age group. Pooled analyses suggest similar efficacy and safety to younger adults, but clinical experience is more limited.
- Immunocompromised patients: As with any biologic, theoretical concern for altered immune responses, though anti-drug antibody rates were low (0.4% in controlled trials, 1.6% long-term).
In March 2025, the FDA updated labeling for CGRP antagonists, including fremanezumab, 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, but was most frequently reported within 7 days of initiation. Some cases required pharmacological treatment or hospitalization. New-onset or worsening Raynaud’s phenomenon has been reported with a median onset of approximately 71 days after dosing, with many cases involving serious outcomes including hospitalization and disability related to debilitating pain. Most cases resolved after discontinuation of the CGRP antagonist.
Patient Counselling
Purpose of Therapy
Fremanezumab is a preventive treatment designed to reduce the frequency and severity of migraine attacks. It does not stop a migraine once it has started; patients should continue to use their acute migraine medications (triptans, analgesics) as needed. The goal of preventive therapy is typically a 50% or greater reduction in monthly migraine days, which is considered a clinically meaningful response. It may take up to 3 months to fully assess the benefit of treatment.
How to Take
Fremanezumab is given as a subcutaneous injection in the abdomen, thigh, or upper arm. It can be self-administered at home after initial training, or administered by a healthcare provider. Allow the prefilled syringe or autoinjector to reach room temperature for 30 minutes before injection. Do not warm using hot water or a microwave. Do not freeze or shake the product. The solution should appear clear to opalescent, colorless to slightly yellow; do not use if cloudy, discolored, or containing particles. Store refrigerated (2–8°C); if kept at room temperature (up to 30°C), use within 7 days.
Sources
- Teva Pharmaceuticals USA, Inc. AJOVY (fremanezumab-vfrm) injection, for subcutaneous use: US Prescribing Information. Revised August 2025. https://www.ajovy.com/globalassets/ajovy/ajovy-pi.pdf Primary source for dosing, pharmacokinetics, adverse reactions, contraindications, and all labeling data including the 2025 pediatric expansion.
- European Medicines Agency. Ajovy (fremanezumab) EPAR — Summary of Product Characteristics. https://www.ema.europa.eu/en/medicines/human/EPAR/ajovy EU regulatory assessment providing SmPC data and European approval context for adult migraine prevention.
- Dodick DW, Silberstein SD, Bigal ME, et al. Effect of fremanezumab compared with placebo for prevention of episodic migraine: a randomized clinical trial (HALO EM). JAMA. 2018;319(19):1999–2008. doi:10.1001/jama.2018.4853 Pivotal phase 3 trial (Study 1) establishing efficacy of monthly and quarterly regimens in episodic migraine (N=875).
- Silberstein SD, Dodick DW, Bigal ME, et al. Fremanezumab for the preventive treatment of chronic migraine (HALO CM). N Engl J Med. 2017;377(22):2113–2122. doi:10.1056/NEJMoa1709038 Pivotal phase 3 trial (Study 2) in chronic migraine (N=1130) demonstrating significant reductions in headache days.
- Ferrari MD, Diener HC, Ning X, et al. Fremanezumab versus placebo for migraine prevention in patients with documented failure to up to four migraine preventive medication classes (FOCUS). Lancet. 2019;394(10203):1030–1040. doi:10.1016/S0140-6736(19)31946-4 Phase 3b trial demonstrating efficacy in difficult-to-treat patients who had failed 2–4 prior preventive medication classes.
- Goadsby PJ, Silberstein SD, Yeung PP, et al. Long-term safety, tolerability, and efficacy of fremanezumab in migraine: a randomized study. Neurology. 2020;95(18):e2487–e2499. doi:10.1212/WNL.0000000000010600 12-month open-label extension study (HALO-LTS) providing long-term safety data in 1890 patients.
- 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.
- Melo-Carrillo A, Strassman AM, Nir RR, et al. Fremanezumab — a humanized monoclonal anti-CGRP antibody — inhibits thinly myelinated (Aδ) but not unmyelinated (C) meningeal nociceptors. J Neurosci. 2017;37(44):10587–10596. doi:10.1523/JNEUROSCI.2211-17.2017 Preclinical study elucidating the selective peripheral mechanism of fremanezumab on A-delta meningeal nociceptors.
- 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.
- Cohen-Barak O, Weiss S, Rasamoelisolo M, et al. Population pharmacokinetic modelling and simulation of fremanezumab in healthy subjects and patients with migraine. Br J Clin Pharmacol. 2020;86(5):983–993. doi:10.1111/bcp.14207 Population PK model establishing bioavailability (~66%), covariate effects (body weight), and absence of CYP-mediated interactions.
- VanderPluym JH, Halker Singh RB, Dodick DW. Fremanezumab in the treatment of migraines: evidence to date. J Pain Res. 2019;12:2585–2597. doi:10.2147/JPR.S166427 Narrative review summarizing phase 2/3 clinical evidence, pharmacokinetics, and safety profile of fremanezumab.
- Goadsby PJ, Blumenfeld AM, Engel ER, et al. Efficacy and safety of fremanezumab in clinical trial participants aged ≥60 years with episodic or chronic migraine. J Headache Pain. 2022;23(1):38. doi:10.1186/s10194-022-01408-2 Pooled subgroup analysis confirming comparable efficacy and safety in older patients (≥60 years) across three phase 3 trials.