The work described here was presented at the UKCPA Virtual Conference Poster Day 2021
Chronic migraine is defined as 15 or more headache days per month for at least three months, of which eight or more are migraines.
Erenumab is a human monoclonal antibody that binds to the calcitonin gene-related peptide receptor, thus preventing migraine attacks. The most common side effects reported are injection site reactions, constipation, muscle spasms and pruritus but these are all under five percent occurrence.
In the NHS Greater Glasgow and Clyde guideline, erenumab is approved for prophylaxis in patients who have trialled four prior prophylactic treatments in addition to Botox®. A positive response is defined as either a ≥30 percent reduction in headache days or a ≥50 percent reduction in migraine days from baseline.
We wanted to explore how many patients showed a positive response to erenumab, and the side effects experienced.
The study included patients prescribed erenumab at a pharmacist or nurse clinic between March and October 2020. Data was collected at baseline and at a three-month review appointment.
The therapeutic response to erenumab has resulted in fewer return appointments to the headache clinic
Seventy patients were included; the majority were female (86 percent) and the mean age was 45 years (range 18–74). The mean number of prophylactics previously trialled was 7.3 (range 4-12) and the mean baseline headache days was 26 (range 15-28).
Overall, 79 percent of this sample (n=55) experienced a positive response to erenumab:
• Almost half (47%; n=33) had a reduction in both headache and migraine days
• A small number (9%; n=6) had 30 percent or more reduction in headache days only
• Almost a quarter (23%; n=16) had 50 percent or more reduction in migraine days only
• A fifth (21%; n=15) had no response.
Seventy percent (n=49) of patients achieved a 50 percent or more reduction in migraine days compared to 41 percent in the published trial.
The most common side effect was constipation, which one third of the sample experienced. Three percent of the sample experienced hair loss, two percent experienced injection site reactions, fatigue or itching, and one percent experienced blistering, restless legs, rash, nausea, diarrhoea, insomnia or flushes. Erenumab was discontinued in two percent of patients due to adverse effects.
The therapeutic response to erenumab has resulted in fewer return appointments to the headache clinic. Adherence to the guideline in terms of required number of prior prophylactic treatments was 100 percent.
This study demonstrated that the development of a prescribing pharmacist-led clinic improved access to erenumab and reduced waiting times. The pharmacist is now an integral member of the headache team.
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Competing interest statement:
The author declares: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.