Fremanezumab

• Migraine Prevention
• Chronic Migraine
• Episodic Migraine
• CGRP-Targeted Therapy

Fremanezumab is a fully human monoclonal antibody that targets calcitonin gene-related peptide (CGRP) ligand, used for the preventive treatment of migraine in adults. This biologic offers flexible dosing options with monthly or quarterly administration for migraine prevention.

Mechanism of Action

Fremanezumab is a humanized IgG2Δa monoclonal antibody that selectively binds to calcitonin gene-related peptide (CGRP) ligand, preventing it from binding to its receptor. CGRP is a 37-amino acid neuropeptide that plays a central role in migraine pathophysiology. During migraine attacks, CGRP is released from trigeminal sensory neurons and contributes to vasodilation, neurogenic inflammation, and sensitization of pain pathways. By binding and neutralizing CGRP, fremanezumab prevents CGRP-mediated signaling, reducing the frequency and severity of migraine attacks. Unlike erenumab (which blocks the CGRP receptor), fremanezumab targets the CGRP ligand itself.

Available Formulations

Fremanezumab is available as a solution for subcutaneous injection in single-dose prefilled syringes and prefilled autoinjectors containing 225 mg/1.5 mL. The medication requires refrigeration but can be kept at room temperature (up to 86°F/30°C) for up to 24 hours (syringes) or 7 days (autoinjectors). Patients can self-inject after proper training.

Medical Uses

Fremanezumab is FDA-approved for the preventive treatment of migraine in adults. It is effective for both episodic migraine (less than 15 headache days per month) and chronic migraine (15 or more headache days per month, with at least 8 migraine days). Clinical trials demonstrated significant reductions in monthly migraine days compared to placebo. The medication is not intended for acute treatment of migraine attacks.

Dosing Guidelines

Two dosing options are available: monthly dosing of 225 mg subcutaneously once monthly, or quarterly dosing of 675 mg (three consecutive 225 mg injections) subcutaneously once every 3 months. When switching between dosing regimens, the new regimen should begin on the next scheduled dosing date. Injection sites include the abdomen, thigh, or upper arm; for the quarterly dose, all three injections should be given consecutively in different sites.

Important Safety Information

Hypersensitivity reactions including rash, pruritus, urticaria, and facial swelling have been reported. In rare cases, serious hypersensitivity reactions such as angioedema and anaphylaxis have occurred. The medication should be discontinued if serious hypersensitivity reaction occurs. There are no contraindications listed in the prescribing information, but patients with known hypersensitivity to fremanezumab or excipients should not use this medication.

Drug Interactions

No formal drug interaction studies have been conducted. Fremanezumab is not expected to be metabolized by cytochrome P450 enzymes as it is a monoclonal antibody eliminated through catabolism. It can be used concomitantly with acute migraine treatments (triptans, ergots, NSAIDs) and other preventive medications (beta-blockers, anticonvulsants, antidepressants) based on clinical trial experience.

Special Populations

There are limited data on fremanezumab use during pregnancy. Animal studies did not show adverse effects on reproduction. Women should be advised of the lack of human data. It is unknown whether fremanezumab is excreted in human breast milk; the developmental and health benefits of breastfeeding should be considered. Safety and efficacy have not been established in pediatric patients. Clinical trials included patients aged 18-70; no overall differences in safety were observed in elderly patients based on limited data. No dose adjustment is needed for renal or hepatic impairment.