Objective:

To examine adherence to branded preventive chronic migraine (CM) treatments among patients who initiated calcitonin gene–related peptide monoclonal antibody (CGRP mAb) treatment and subsequently added on or switched to another branded preventive treatment.

Background:

OnabotulinumtoxinA (OnabotA) and CGRP mAbs treat CM prophylactically. CM patients treated with a CGRP mAb may introduce a subsequent treatment, but little is known about adherence to the subsequent CM treatment.

Design/Methods:

This retrospective cohort study included adult CM patients (ICD-10-CM G43.7XX) treated with a CGRP mAb and a subsequent CM treatment from IBM MarketScan® claims databases (05/17/2018 – 06/30/2021). The index date was the first claim date of subsequent treatment. Patients were categorized into three cohorts: switch to another CGRP mAb, switch to OnabotA, and add-on OnabotA (concomitant with CGRP mAb ≥28 days immediately following index). Baseline characteristics were assessed during the 6-month pre-index period. Adherence was defined as ≥80% of days covered on index treatment over the 6-month follow-up period. Difference in adherence between cohorts was compared using a Chi-square test and adjusted for baseline characteristics using logistic regression.

Results:

A total of 1315 patients were included; 745 switched to a CGRP mAb, 449 switched to OnabotA, and 121 added OnabotA. Mean age was 41.9, 39.8, and 41.3 years, respectively, and all cohorts were ≥86% female. Adherence was highest for add-on OnabotA, followed by switch to OnabotA, and, lastly, switch to CGRP mAb (68.6% vs 61.5% vs 33.2%, respectively; P<0.0001). After adjustment, switch to OnabotA and add-on OnabotA cohorts had 3.3 (95% CI: 2.5–4.2) and 4.6 (95% CI: 3.0–7.0) times higher odds of adherence compared with the switch to CGRP mAb cohort.

Conclusions:

Following a CGRP mAb, adding on or switching to OnabotA as a subsequent CM treatment was associated with significantly higher adherence over 6 months compared with switching to another CGRP mAb.