Medically reviewed by Susan Kerrigan, MD and Marianne Madsen
Many who suffer from episodic migraines (EM) have tried 2-4 preventive treatments and found them to be ineffective. However, results from the long-term extension of the LIBERTY study evaluating monthly erenumab monotherapy demonstrated continuous improvement on all efficacy outcomes in those who have not been responsive to 2-4 preventive migraine treatments.
Background on Erenumab
Erenumab, a human monoclonal antibody, binds to the calcitonin gene-related peptide (CGRP) receptor to stop activation, contributing to fewer migraines. In previous randomized studies, Erenumab has proven to be safe and effective in EM and chronic migraines. While the results from the phase 3b trial, “Study Evaluating the Effectiveness of AMG 334 Injection in Preventing Migraines in Adults Having Failed Other Therapies (LIBERTY),” showed the efficacy of erenumab 140 mg in participants with EM who used 2-4 prior preventive treatments unsuccessfully, longer-term data was needed since adherence to preventive protocols is low. Health care professionals can use this information to talk with their patients about the importance of being consistent with their preventive therapy. Currently ongoing, results from the 3-year open-label extension phase (OLEP) of the LIBERTY study may also prove to be resourceful when published.
Clinical Trial Outcomes and Results
The researchers reported results based on participants who completed 64 weeks in the LIBERTY study and 52 weeks (1 year) of OLEP. Efficacy outcomes (OLEP) “included achievement of ≥50% reduction in monthly migraine days (MMD) compared to baseline, change in MMD from baseline, and change in everyday activities and physical impairment.” Researchers measured outcomes every month during the first 3 months and then the last month of each quarter through week 64.
Among the group of patients that continued with erenumab, the 50% responder rate improved from 29.9% at weeks 9-12 to 44.3% at weeks 61-64. In the OLEP, the 50% responder rate climbed from weeks 13-16 until weeks 37-40 and remained stable throughout weeks 61-64. Participants who started erenumab in the OLEP (switched from placebo during the double-blind treatment phase) showed continuous improvement from week 13 onward. The safety of erenumab was congruent with what was seen in prior clinical trials.
The data from year 1 of the 3-year OLEP of the LIBERTY study revealed consistent efficacy, a low dropout rate, and great tolerability.