The following is the summary of “Medium-term real-world data for erenumab in 177 treatment resistant or difficult to treat chronic migraine patients: persistence and patient reported outcome measures after 17–30 months,” published in the January 2023 issue of Headache and Pain by Troy, et al. 

Numerous migraine sufferers are classified as treatment- or medically-resistant or difficult-to-treat cases because they do not respond well to standard preventive medications. Short-term clinical trials with calcitonin gene-related peptide monoclonal antibodies, a relatively new molecular treatment for episodic and chronic migraine, have shown success in roughly 40-50% of all chronic migraine patients. Response to treatment in migraine can be evaluated with the aid of Patient Related Outcome Measures (PROM) or Quality of Life (QoL) questionnaires. Although open-label extension studies with erenumab are now available, there is a shortage of long-term real-world data on patients’ quality of life with chronic and treatment-resistant migraine. A total of 177 patients with CM who had not responded to previous treatment began receiving erenumab (70 mg or 140 mg subcutaneous injection every 4 weeks) at one of the specialized Headache Clinics.

For 174 of these, the initial injection occurred between December 2018 and October 2019. Prior to beginning therapy with erenumab, and at 3, 6, and 12-month intervals thereafter, patients were examined using the Headache Impact Test 6, the Migraine Associated Disability Assessment test, and the Migraine-Specific Quality of Life Questionnaire. A subjective clinical improvement of at least 30% (as stated by the patient) was used to justify continuing treatment, as was documentation in the form of diaries and QoL questionnaires. Here we report on the quality of life assessments performed on this sample of 177 individuals. Traditional oral prophylactic medications (like topiramate, candesartan, propranolol, or amitriptyline), at least 2 cycles of PREEMPT protocol onabotulinumtoxin A, and (in a small number of cases) neuromodulation with single-pulse Transcranial Magnetic Stimulation were all used for migraine prevention in the past.

During the first year of treatment, 38.4%  of the 177 individuals who began taking erenumab discontinued it due to ineffectiveness (no significant benefit or just minimal improvement) or probable side effects. About 61% of patients surveyed (109/187) who had been on treatment for 6-12 months said they felt significantly better and wanted to continue it. In the time span between 6 months and 6 years, 12 of these 109 patients quit taking their medication (mainly due to a worsening of their migraine). As of June 2021 (treatment duration: 17-30 months, median: 25 months), 97/177 (54.8%) patients were still receiving treatment. About half of the patients with CM who participated in their erenumab clinical trials experienced a subjective benefit and were still taking the drug between 17 and 30 months afterward.