Long-Term Efficacy and Safety of Erenumab: Results From 64 Weeks of the LIBERTY Study

Abstract

Objective: To report the efficacy and safety of erenumab among episodic migraine (EM) patients who were unsuccessful on 2-4 preventive treatments observed at week 64 of Open-Label Extension Phase (OLEP) of the LIBERTY study (ClinicalTrials.gov NCT03096834).

Methods: The OLEP evaluating monthly erenumab 140 mg for 3 years, enrolled 240 patients who completed the double-blind treatment phase (DBTP) of 12 weeks during which they received placebo or erenumab 140 mg subcutaneous injections every 4 weeks as monotherapy. Efficacy outcomes were evaluated through the initial 52 weeks of OLEP (from DBTP baseline to total 64 weeks) in the overall population, patients receiving erenumab in DBTP, and patients from DBTP placebo arm who switched to erenumab in OLEP. Endpoints included reduction of ≥50% in monthly migraine days (MMD) from DBTP baseline and change in MMD from DBTP baseline, Headache Impact Test, and Migraine Physical Function Impact Diary (Physical Impairment and Everyday Activities) scores.

Results: Altogether, the week 52 visit of the OLEP was completed by 204/240 (85.0%) patients. Among patients continuing erenumab, the 50% responder rate increase from 29.9% at weeks 9%-12% to 44.3% at week 61-64. The 50% responder rate in patients who initiated erenumab in the OLEP remained higher in the OLEP (50.0% at week 61-64) than during DBTP (14.2% at weeks 9-12) compared to patients in continuous erenumab arm. In the OLEP, the 50% responder rate for the overall population increased from weeks 13-16 until weeks 37-40 and then remained stable through weeks 61-64. Patients treated with erenumab in DBTP showed sustained effects on all efficacy outcomes; those initiating erenumab in the OLEP demonstrated continued improvement from week 13 onward. Adverse events (AEs) were reported, considering both treatment groups, by ∼80.8% (serious AEs [SAEs] by 6.7%); 76.3% (5.9%) in the continuing erenumab arm; and 85.2% (7.4%) in those starting erenumab in OLEP. No deaths were reported.

Conclusions: In patients with EM who were unsuccessful on 2-4 prior preventive treatments, the LIBERTY study demonstrated sustained efficacy on erenumab monotherapy treatment through 64 weeks in both treatment arms. Safety of erenumab was consistent with that observed in previous clinical trials.

Classification of evidence: The current study provides Class IV evidence on data from patients with episodic migraine, that erenumab is safe and provides sustained efficacy at 52 weeks.

Clinicaltrialsgov identifier: NCT03096834.

Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.

Figures

Figure 1. LIBERTY Study Design

Follow-up phase 16 weeks after the last dose of the study drug. *The open-label extension phase (OLEP) is ongoing. LIBERTY = A Study Evaluating the Effectiveness of AMG 334 Injection in Preventing Migraines in Adults Having Failed Other Therapies; n = Number of patients from each treatment arm in the double-blind treatment phase entering into the OLEP; N = Number of patients in each treatment arm in the DBTP; QM = once monthly; SC = subcutaneous.

Figure 2. Patient Disposition

DBTP = double-blind treatment phase; OLEP = open-label extension phase.

Figure 3. Responder Rate, ≥50% Reduction in Monthly Migraine Days

Data were calculated as number of responders (n)/total number of participants in the treatment arm with response variable defined (N). OLEP = open-label extension phase.

Figure 4. Change in Monthly Migraine Days From Baseline Until Week 64 of the OLEP

DBTP = double-blind treatment phase; n = total number of participants in the treatment arm with response variable defined; OLEP = open-label extension phase.