Real-world treatment switching and healthcare costs of onabotulinumtoxinA and calcitonin gene-related peptide monoclonal antibodies in Medicare patients with chronic migraine: a retrospective claims analysis

Evaluate treatment switching and healthcare costs of onabotulinumtoxinA (onabotA) compared to calcitonin gene-related peptide (CGRP) monoclonal antibodies (mAbs) for the preventive treatment of chronic migraine (CM). Adult patients with CM who initiated onabotA or a CGRP mAb between 1 October 2021 and 31 December 2023 were identified from the Optum de-identified Clinformatics Data Mart database. Index date was the first recorded treatment claim and patients must have had continuous Medicare coverage 12-months pre- and post-index period. Treatment switching, defined as ≥1 claim for a different branded migraine preventive treatment in the 12 months post-index period, was evaluated. Two additional treatment switch definitions were evaluated. All-cause healthcare resource utilization and costs were evaluated over the 12-month follow-up. Multivariable logistic regression adjusted for baseline characteristic differences when comparing odds of switching between onabotA and CGRP mAbs. Patient information on CM severity was not available in the database and not reported. Of 887 patients identified, 367 initiated onabotA and 520 a CGRP mAb as index treatment. After 12 months of follow-up, 8.7% of onabotA users and 18.3% of CGRP mAb users initiated a different branded migraine preventive treatment. After adjusting for differences in baseline characteristics, CGRP mAb users had 134% higher odds of switching treatment during the 12-month follow-up compared to onabotA users (OR, 2.34; 95% CI: 1.49, 3.67, p Outcomes could only be adjusted for known and observed confounders, which could introduce bias between comparators. Patients with CM on a CGRP mAb were significantly more likely to switch to a different branded migraine preventive treatment within 12 months of treatment initiation compared to those on onabotA. Total costs were comparable between treatments.