Number Needed to Treat and Cost Per Responder Analysis of Anti-CGRP Monoclonal Antibodies for Migraine Prevention in Adults for Whom Prior Preventive Treatments have Failed

Introduction: Four monoclonal antibodies (mAbs) targeting calcitonin gene-related peptide (CGRP) signaling are approved for migraine prevention and commonly prescribed/reimbursed after the failure of repurposed anti-migraine medications. Participants achieving clinical response [e.g., ≥ 50% monthly migraine days (MMDs) reduction] during an anti-CGRP mAb trial are likely to continue treatment. We calculated number needed to treat (NNT) and quarterly cost per responder (CPR) across four anti-CGRP mAbs. Methods: Data were from randomized, double-blind, placebo-controlled phase 3b clinical trials that evaluated anti-CGRP mAbs (eptinezumab, fremanezumab, galcanezumab, erenumab) for migraine prevention in adults with episodic or chronic migraine for whom 2–4 prior preventive treatments have failed. NNT was calculated as 1 divided by absolute risk reduction (difference between active treatment and placebo in the proportion of participants with ≥ 50% or ≥ 75% MMD reduction over Weeks 1–12). CPR was calculated by multiplying NNT by the quarterly (3-month) drug acquisition CPR (£), based on the reimbursed list price in the United Kingdom (CPR could not be calculated for eptinezumab 300 mg). Statistical comparisons were not made. Results: All anti-CGRP mAbs demonstrated higher rates of ≥ 50% and ≥ 75% MMD reduction than their respective placebo (p < 0.05). The NNT to achieve ≥ 50% MMD reduction ranged from 2.7 (eptinezumab 300 mg) to 6.0 (erenumab 140 mg), and for ≥ 75%, 6.0 (eptinezumab 300 mg) to 16.2 (fremanezumab 675 mg/q). The cost per ≥ 50% responder ranged from £4647 (eptinezumab 100 mg) to £7009 (erenumab 140 mg), and for ≥ 75%, £9850 (eptinezumab 100 mg) to £21,862 (fremanezumab 675 mg/q). Conclusions: These results show that, for most anti-CGRP mAbs, a low number of participants (< 10) with migraine need to be treated to achieve one person with a ≥ 50% or ≥ 75% reduction in MMDs over Weeks 1–12, with CPR ranging from £4647 (eptinezumab 100 mg) to £21,862 (fremanezumab 675 mg/q).