fremanezumab
Brand: Ajovy
Prototype: erenumab
Drug Class: anti-CGRP monoclonal antibody
Drug Family: antimigraine
Subclass: humanized IgG2a anti-CGRP ligand antibody
Organ Systems: cns
Mechanism of Action
Binds directly to the CGRP ligand (not the receptor), preventing it from activating its receptor. Unlike erenumab (which targets the receptor), fremanezumab neutralizes the neuropeptide itself. Monthly or quarterly SC dosing options.
CGRP ligand (calcitonin gene-related peptide)
Indications
- preventive treatment of migraine in adults
Contraindications
- hypersensitivity to fremanezumab
Adverse Effects
Common
- injection site reactions
- constipation
- fatigue
Serious
- hypersensitivity reactions
Pharmacokinetics (ADME)
| Absorption | subcutaneous; bioavailability ~57% |
| Distribution | Vd ~3.6 L |
| Metabolism | proteolytic degradation |
| Excretion | catabolism |
| Half-life | 31 days |
| Onset | clinical benefit within 1-3 months |
| Peak | 5-7 days |
| Duration | monthly (225 mg) or quarterly (675 mg) |
| Protein Binding | not applicable |
| Vd | 3.6 L |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| none significant | no CYP450-mediated interactions | minor |
Nursing Considerations
- Two dosing regimens: 225 mg monthly or 675 mg (3 injections of 225 mg) quarterly; clarify which regimen is prescribed.
- Allow to warm to room temperature 30 minutes before injecting; rotate injection sites.
- Assess for constipation at every visit; rare severe cases require holding treatment.
- Response assessment at 3-6 months; 50% responder rate in clinical trials.
Clinical Pearls
- Fremanezumab targets the CGRP ligand directly (vs. erenumab targeting the receptor); clinically the efficacy and adverse effects are similar across the class.
- Quarterly dosing option (675 mg q3 months) is unique among anti-CGRP mAbs and may improve adherence for patients with needle aversion or difficulty with monthly injections.
Safety Profile
Pregnancy avoid
Lactation avoid
Renal Adjustment Not required
Hepatic Adjustment Not required
TDM Not required
Guideline Update pending
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.