Real-world short-term effectiveness of erenumab after single versus multiple prior preventive treatment failures

BACKGROUND: Erenumab, a monoclonal antibody targeting calcitonin gene-related peptide receptor, has been approved in Germany since 2018 for migraine prophylaxis. Initially, reimbursement regulations restricted its use to drug-resistant patients who had failed or were unsuitable for conventional preventive treatments. Over time, initiation after failure of only one prior preventive treatment became possible. As earlier initiation of effective preventive therapy may improve clinical outcomes, we compared the effectiveness of erenumab in patients with single versus multiple prior preventive treatment failures. METHODS: In this retrospective single-center study, data from 196 patients with episodic or chronic migraine who received erenumab for at least three months were analysed. Patients were categorised into a multiple prior preventive therapy (MPT) group (n = 140), comprising individuals with two to six previous preventive treatment failures, and single preventive therapy (SPT) group (n = 56), including patients who had received no more than one prior treatment failure before initiating erenumab. To evaluate the association between prior treatment exposure and treatment response, a multivariate logistic regression analysis was performed with achievement of a ≥ 50% reduction in monthly headache days (MHD) as the primary outcome. Subgroup analyses, LASSO-based variable selection, and propensity score weighting were conducted as sensitivity analyses. RESULTS: A clinically meaningful treatment response (50% MHD response) was achieved by 35.7% (n = 20/56) of patients in the SPT group and 30.7% (n = 43/140) in the MPT group. No significant difference in treatment effectiveness was observed between groups. In the adjusted logistic regression model, SPT was not significantly associated with treatment response (SPT vs. MPT: adjusted OR 1.39, 95% CI 0.53-3.69; p = 0.5). CONCLUSION: Short-term effectiveness of erenumab was comparable in patients with no more than one versus multiple prior preventive treatment failures, suggesting that treatment response is not solely dependent on the number of previous preventive treatment failures. These findings should be interpreted in light of the retrospective single-center design and the limited sample size, which resulted in relatively wide confidence intervals.