Neurology - Anti CGRP-MAb treatment for Migraine

What is CGRP?

Calcitonin gene-related peptide (CGRP) is a chemical signal produced by pain nerves to communicate with each other. It is involved in different pain processes around the body including migraine.

CGRP has also been shown to cause blood vessels to dilate (open wider). Studies have demonstrated that CGRP levels increase in the body during a migraine episode. Therefore, blocking this chemical signal can improve migraine.

What is anti-CGRP MAb treatment?

Anti-CGRP MAb treatments work by blocking CGRP. They do this by either binding to CGRP itself, ‘mopping it up’, or by stopping the pain nerve fibres from being activated by CGRP (blocking the CGRP receptors).

The treatment is given by a single injection every month, although two of them (Ajovy and Vyepti) can be given every 3 months.

There are currently 4 anti-CGRP MAbs (commercial names in brackets):

• Erenumab (Aimovig)
• Fremanezumab (Ajovy)
• Galcanezumab (Emgality)
• Eptinezumab (Vyepti)

What is the evidence that anti-CGRP MAbs can help with migraine?

There are several clinical trials for each treatment which demonstrate that about 50% of people have a meaningful reduction in their migraine.

The treatment is not a cure, and it doesn’t usually stop all migraine or headaches.

How do we decide whether anti-CGRP MAbs are appropriate?

The treatments are licensed in the UK for treating people with 4 or more migraine days per month. The treatments are licensed and funded by the NHS for people with episodic migraine (4-14 migraine days per month) or chronic migraine.

Migraine is defined as chronic if there are 15 or more headache days per month, at least 8 of which are migraine type headaches.

In addition:

• 3 different migraine preventative medications haven’t worked, when taken for at least 3 months at maximum tolerated target doses. Alternatively, they are unsuitable because of safety concerns or not tolerated
• Any analgesic or triptan overuse has been managed appropriately
• Your headache diary must have been completed for at least one month before the start of treatment

What does the treatment involve?

• A headache diary which needs to be completed to record the number and severity of headaches/migraine occurring after the injections. Without these diaries, we cannot provide treatment
• Our headache specialist nurse will contact you to discuss the treatment and ask for the number of headache days recorded in your diary (baseline)
• Most of these treatments are given by a single injection once per month. The drug is administered using an automated injection device. This is easy to use. We have information leaflets for each drug explaining how to use the specific device. Vyepti is given by an intravenous infusion (drip into a vein), once every 3 months on our day case ward
• The injection pen will be delivered to your address by a homecare company
• Our headache specialist nurse will contact you after 10-12 weeks to assess the treatment response

Possible side effects

• Pain, hardening or redness around the injection site (1 in 20 people)
• Constipation (about 3 in 100 people). This generally settles, but if not, we can change to another one of the anti-CGRP-MAbs
• Theoretically, these treatments might cause blood pressure to increase. This isn’t a side effect listed in the UK information. Nonetheless, it’s important to check blood pressure before starting treatment and after a week’s treatment. If your blood pressure is too high, we may delay anti-CGRP-Mab treatment until it’s controlled
• A research study conducted in mice showed that CGRP blocking drugs might increase the risk of a stroke. For this reason, these treatments need to be used with caution in people who have a higher risk of stroke or other vascular diseases (diseases causing narrowing of the blood vessels which feed the brain, heart and other organs)

Please inform your clinician if you:

• Have a history of cardiovascular diseases, such as myocardial infarction (heart attack), stroke, transient ischaemic attacks (TIA)
• Unstable angina or have had coronary artery bypass surgery or angioplasty
• Have or have suffered with atrial fibrillation
• You smoke, are overweight, have high cholesterol and/or diabetes

Pregnancy and breast feeding

It is uncertain whether these treatments are safe in pregnancy and breast feeding. Therefore, they should not be used if you are pregnant, breast feeding or planning on conceiving in the near future. Please discuss it with your clinician.

How to store your medication

• Store in a refrigerator (between 2-8°C)
• Do NOT freeze
• This medicine may be removed from the fridge and stored at a temperature below 25°C for a maximum period of a week

Contact details and further advice

The Headache Team - Salford Royal Hospital
Telephone: 0161 206 2563 / 0161 206 5507

Useful websites:

www.migrainetrust.org
www.migraine.org.uk
www.nice.org.uk