To determine the number needed to treat (NNT), number needed to harm (NNH), and likelihood of being helped or harmed (LHH) in the FOCUS study.

Fremanezumab, a fully-humanized monoclonal antibody (IgG2Δa) that selectively targets calcitonin gene-related peptide (CGRP) has demonstrated efficacy for the preventive treatment of migraine in adults.

In the 12-week, double-blind, placebo-controlled study, patients were randomized (1:1:1) to quarterly fremanezumab, monthly fremanezumab, or monthly placebo. NNT was based on responder analysis defined as ≥30% and ≥50% reduction in monthly migraine days at 12 weeks for CM and EM patients, respectively. NNH was based on discontinuations due to adverse events (AEs); if NNH ≤0, it was imputed as 1000. LHH is an indirect measure of effect size and determined as NNH divided by NNT.

Among CM patients (N=509) receiving quarterly fremanezumab, monthly fremanezumab, and placebo, respectively, response rates were 49%, 54%, and 19%, and discontinuations due to AEs were 0%, 2%, and <1%. Among EM patients (N=328) receiving quarterly fremanezumab, monthly fremanezumab, and placebo, respectively, response rates were 47%, 43%, and 10%, and discontinuations due to AEs were <1% in all 3 groups. For quarterly and monthly fremanezumab, respectively, these results translated to NNT of 3.3 and 2.9, NNH of 1000 and 71, and LHH of 300 and 25 for CM patients; to NNT of 2.7 and 3.0, NNH of 1000 and 1000, and LHH of 370 and 330 for EM patients; and to NNT of 3.0 and 2.9, NNH of 1000 and 333, and LHH of 330 and 113 for the combined CM/EM group.

The NNT, NNH, and LHH were generally favorable for both fremanezumab dosing regimens in this population with EM or CM and inadequate response to 2-4 prior migraine preventive treatment classes.