Essentials about anti-CGRP drugs for Migraine prevention newly approved by FDA
M3 India Newsdesk Oct 17, 2018
In a groundbreaking news, the FDA recently approved the first anti CGRP , a new class of migraine drugs that aim to fight painful migraine headaches before they start. Here is a sneak peek into this new Anti CGRP Migraine Treatment Options.
Why is CGRP targeted?
Studies have shown CGRP is released during severe migraine attacks and the reversal of the attack with effective triptan treatment normalises those levels.
CGRP is a 37-amino acid neuropeptide and plays an integral role in the pathophysiology of migraine.
CGRP is released during migraine that localises in the trigeminal ganglia and spinal trigeminal nuclei. An increase in the plasma levels of CGRP have been found during migraine episodes and an infusion of CGRP has also shown to evoke migraine in patients with the condition. These findings make CGRP a suitable target for the prevention of migraine.
How does anti-CGRP therapy work?
The monoclonal antibodies work against CGRP and against the receptor to which CGRP binds.
Such antibodies against CGRP or the CGRP receptor have been developed recently. Chief among them are, fremanezumab, eptinezumab and galcanezumab, which are humanized antibodies and erenumab, a fully human antibody.
These agents possess excellent pharmacokinetic properties like a long Tmax and T1/2 and can be administered through the parenteral route.Of the four, erenumab (Aimovig) and fremanezumab (Ajovy) have recently been approved for clinical use.
Which anti-CGRP therapies have been FDA approved?
Erenumab (Aimovig) – First in class
Amgen and Novartis’ erenumab (Aimovig) was approved in May 2018. It is the first in class treatment designed to prevent migraines by blocking CGRP receptor. The drug targets the CGRP receptor rather than the CGRP molecule itself and this factor differentiates it from other candidates in development.
The approval was based on the STRIVE trial for the prevention of an episodic migraine. A significant 3.7-day reduction in monthly migraine days versus 1.8 days for placebo was achieved, and subsequent analysis showed that effects on monthly migraine days were sustained for up to 15 months.
Aimovig 70 mg is self-administered once a monthly by way of Amgen’s SureClick autoinjector similar to an insulin pen, thus making it a convenient treatment option.
Fremanezumab (Ajovy) – Flexible dosing can be an attractive tool for improving compliance
Teva’s fremanezumab is the second FDA-approved preventive migraine treatment and works by blocking the activity of CGRP itself.
In the HALO-CM (chronic migraine) trial, patients receiving fremanezumab (monthly or quarterly) reported at least a 50% reduction in average number of headache days per month vs. the placebo group. In the HALO-EM (episodic migraine) trial, patients receiving fremanezumab reported 1.5 (monthly) and 1.3 (quarterly) fewer headache days compared to placebo.
Both the studies were conducted in patients previously treated with topiramate or onabotulinumtoxinA (Botox, Allergan) and thus fremanezumab can be an effective treatment option for patients in whom other preventive therapies have failed.
Fremanezumab has a half-life that supports a long duration of action and long intervals between doses. Two recommended subcutaneous dosing options are available for fremanezumab.
- 225 mg monthly
- 675 mg every 3 months (quarterly), which is administered as 3 consecutive subcutaneous injections of 225 mg each
Parenteral delivery systems for both the approved antibodies may also have a significant effect on compliance, presumably decreasing breakthrough attacks arising from skipped or missed doses.
Safety issues with CGRP therapies
CGRP therapies have few or no adverse effects and are as effective as triptans in the acute treatment of migraines, without the cardiovascular effects. The most common adverse reactions encountered in trials were injection site reactions and infections.
Blocking CGRP in migraine patients have shown to be both efficient and well tolerated, however, CGRP and its receptor are abundantly present in both the vasculature, and in the peripheral and central nervous system, and hence are involved in several physiological processes. Therefore, blocking CGRP may pose a risk in subjects with comorbidities such as cardiovascular diseases.
In addition, long-term effects are still unknown. Preclinical studies suggest that blocking CGRP may induce constipation, affect the homeostatic functions of the pituitary hormones or attenuate wound healing. However, these effects have not yet been reported in trials involving humans.
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