What is Ajovy (Fremanezumab)?
Ajovy (fremanezumab-vfrm) is a fully humanized monoclonal antibody that selectively targets and binds calcitonin gene-related peptide (CGRP), a key neuropeptide involved in migraine pathophysiology, and is FDA-approved for the preventive treatment of migraine in adults and children aged 6-17 years weighing ≥45 kg. 1
Mechanism of Action
Fremanezumab works by selectively binding both isoforms of CGRP, a 37-amino acid vasodilatory neuropeptide that plays a central role in the central and peripheral pathophysiological events underlying migraine attacks. By blocking CGRP signaling, fremanezumab prevents the cascade of events that lead to migraine headaches. 2, 3
FDA-Approved Indications
- Adults: Preventive treatment of migraine (both episodic and chronic) 1
- Pediatric patients: Preventive treatment of episodic migraine in children and adolescents aged 6-17 years who weigh ≥45 kg 1, 4
The distinction between episodic and chronic migraine matters: episodic migraine is defined as 1-14 headache days per month, while chronic migraine involves ≥15 headache days per month with migraine features on ≥8 days. 5, 6
Dosing Regimens
For adults, two subcutaneous dosing options are available 1:
- Monthly: 225 mg once monthly
- Quarterly: 675 mg every 3 months (administered as three consecutive 225 mg injections)
For pediatric patients (6-17 years, ≥45 kg), the dosing is weight-based with monthly administration 7, 8:
- 120 mg for patients weighing <45 kg
- 225 mg for patients weighing ≥45 kg
The pharmacokinetics follow a two-compartment model with first-order absorption and a terminal half-life of approximately 30 days in both adults and pediatric patients, with body weight being the primary determinant of drug exposure. 7
Administration Details
Ajovy is administered subcutaneously only and can be given by healthcare professionals, patients, or caregivers after proper training. 1 Key administration points include:
- Remove from refrigerator and allow to reach room temperature for 30 minutes before injection (protected from direct sunlight)
- Do not use heat sources to warm the medication
- Discard if left at room temperature for ≥7 days
- Inject into abdomen, thigh, or upper arm (avoiding tender, bruised, red, or indurated areas)
- Available as prefilled autoinjector or prefilled syringe 1
Clinical Efficacy
In adults with episodic migraine, fremanezumab reduced monthly migraine days by 1.3-1.5 days compared to placebo over 12 weeks, with 38-41% of patients achieving ≥50% reduction in migraine frequency. 9
In adults with chronic migraine, fremanezumab reduced headache days by approximately 4.3-4.6 days per month compared to 2.5 days with placebo, with 38-41% achieving ≥50% response rates. 6
In pediatric patients with episodic migraine, fremanezumab reduced migraine days by 2.5 days per month versus 1.4 days with placebo (difference of 1.1 days), with 47.2% achieving ≥50% reduction compared to 27.0% with placebo. 8
Guideline Positioning
According to the 2025 American College of Physicians guidelines, CGRP monoclonal antibodies (including fremanezumab) are recommended as second-line therapy for episodic migraine prevention in nonpregnant adults who do not tolerate or inadequately respond to first-line agents (beta-blockers, valproate, venlafaxine, or amitriptyline). 5 This conditional recommendation reflects low-certainty evidence but acknowledges that CGRP-mAbs may reduce migraine frequency and have fewer discontinuations due to adverse events compared to topiramate. 5
The 2024 VA/DoD guidelines give a strong recommendation for erenumab, fremanezumab, or galcanezumab for prevention of both episodic and chronic migraine. 10
Safety Profile
Most common adverse event: Injection-site reactions (erythema, induration) occurring in approximately 10% of patients 1, 6, 9, 8
Contraindication: Serious hypersensitivity to fremanezumab or excipients, including anaphylaxis and angioedema (reported in postmarketing surveillance) 1
Important caveat: Hepatic function abnormalities occurred in approximately 1% of patients in clinical trials. 6 The long-term safety profile is excellent with no serious treatment-related adverse events in Phase III trials, and real-world studies suggest the magnitude of efficacy may be even greater than in controlled trials. 2, 3
Clinical Advantages
Fremanezumab demonstrates efficacy in challenging populations including:
- Patients with medication overuse headache
- Patients with previous treatment failures to multiple preventive medications
- Patients with comorbid depression (improving both migraine and depression measures) 3
The excellent tolerability profile significantly improves the likelihood-to-help-versus-harm outcome compared to traditional repurposed medications, making it an optimal choice for migraine prevention despite the modest absolute reduction in migraine days. 3