Fremanezumab is a humanised monoclonal antibody that binds to the calcitonin gene-related peptide (CGRP) ligand, inhibiting the function of CGRP at its receptor, and thereby preventing migraine attacks (BNF). It is given as a sub cutaneous injection of 225 mg once a month, alternatively 675 mg every 3 months.
Fremanezumab is recommended for patients who have 4 or more migraine days a month and for whom at least 3 preventive drug treatments have failed and the drug is supplied by the company under a commercial agreement agreed with NICE. It is unclear if fremanezumab works better than botulinum toxin type A (NICE)
It has a molecular weight of 148,000 and assumed low oral bioavailability. However, there are no studies in breastfeeding mothers and babies although any passing into milk is presumed to be destroyed in the infant gut (LactMed)