Real-world Evidence Points to General High Erenumab Adherence Among Migraineurs

New research illustrates the potential benefits of erenumab among migraineurs in the United States.

New early data from a real-world study of erenumab users, published in Cephalalgia Reports, found high adherence to the drug among migraineurs. According to researchers, this finding—combined with reductions in previously used acute and preventive medications for migraine—points to the drug’s overall potential benefit.

Erenumab is a fully human monoclonal antibody, first approved in 2018, and is administered monthly via self-injection of a 70- or 140-mg dose. It works to block the calcitonin gene-related peptide (CGRP) receptor, which is believed to play a crucial role in the pathophysiology of migraine.

“Currently available oral migraine preventive medications are associated with low adherence rates due to lack of efficacy and/or poor tolerability,” authors explained. “A number of studies have reported on the real-world effectiveness for erenumab at 2, 3, and 6 months. However, there is little reported information on treatment patterns including adherence on erenumab,” they wrote.

To provide descriptive information on real-world use of erenumab for patients seen in routine US clinical practices, researchers conducted a retrospective observational study using the Practice Fusion ambulatory electronic health record (EHR) database.

The study marks the largest in the United States that includes patients from across the country from both specialty and primary care practices. 

Deidentified data were representative of approximately 6% of ambulatory care among these practices and were collected between May 2017 and September 2019. Information on demographics, prescriptions, diagnoses, laboratory test results, and other factors was included in the final analyses.

All adult patients 18 years or older with a diagnosis of migraine or evidence of having migraine and who had at least 1 prescription for erenumab were included in the study (n = 3336). Participants also had an outpatient visit recorded in the EHR system at least 1 year prior to their index date (date of first erenumab prescription).

Of the 3336 eligible patients, 1638 had at least 6 months of follow-up data available and were included in the treatment pattern analysis. The majority of patients included in the study were women (85.9%), with a mean age of 49.1 years. Of the 3336 individuals, roughly 40% had documentation of chronic migraine.

Analyses revealed:

  • Common comorbidities included nonmigraine headache (31.4%), anxiety (24.9%), depression (21%), and hypertension (17.1%).
  • 76.3% of patients initiated on the 70-mg dose of erenumab.
  • Among 1638 patients included in the treatment pattern analysis, 53.1% used acute medications and 55.7% used other nonspecific preventive migraine medications during follow-up, reductions of 9.8% and 10.2%, respectively, over the same period of time before index.
  • Switching to fremanezumab and galcanezumab (other CGRP antagonists) was observed in 12.2% and 13.8% of patients, respectively.
  • The mean proportion of days covered by erenumab at 6 months was 79%.
  • Dosage of erenumab increased (from 70 mg to 140 mg) in 13% and decreased (from 140 mg to 70 mg) in 24.9% of patients.

“Adherence to erenumab in our study was high with reported measures of proportion of days covered (PDC) of 86% at 3 months and 79% at 6 months,” researchers wrote. Furthermore, “reductions in medication usage after erenumab initiation could be viewed as a proxy for migraine improvement and suggests a benefit of erenumab, which is consistent with findings from clinical trials and real-world studies,” they said.

Results may not be generalizable to larger care settings, marking a limitation to the study, and misclassification of medication use may have also been present, as medications prescribed outside of these practices may not have been recorded.

Future investigations should aim to understand changes in patient-reported outcomes from larger patient populations. “Insights from studies with longer follow-up and additional information on changes in healthcare resource utilization and costs is also needed,” authors concluded.


Bogdanov A, Chia V, Bensink M, et al. Early use of erenumab in US real-world practice. Cephalalgia Rep. Published online May 31, 2021. doi:10.1177/25158163211020419