What Role Would CGRP Antibodies Play in Treatment of Migraines?
Everywhere I turn, I seem to hear people talking about these exciting breakthrough treatments for migraines. I wonder why therapy with calcitonin gene-related peptide (CGRP) has caused so much stir in the migraine community. I had never seen so much excitement regarding treatment for migraines since Imitrex (sumatriptan) was first released in the early 1990s.
Could it be that we are desperate for relief that we are ready to bet everything on this new potential therapy? The answer is a resounding yes!
Why the urgency for new migraine treatment?
Migraines have been ranked among the top 20 causes of global disability. Despite the many prophylactic treatments currently available to prevent chronic migraines, only about 50% of those who would benefit from preventive treatments currently use these methods. However, in my experience, the use of prophylaxis has less to do with a doctor’s inability to diagnose migraines appropriately or offer appropriate medications; but rather with a patient’s inability to obtain necessary treatments due to financial constraints and barriers imposed by insurance.
How are CGRPs different?
One of the theories behind the cause of migraines suggests the involvement of a specific peptide (CGRP), which is released from the trigeminal nerve and is responsible for modulating pain. This peptide has been found to be elevated during the pain phase of a migraine with a return to normal with migraine resolution. Thus, theoretically, by blocking these peptides, scientists hope to prevent the pain associated with migraines. It would allow a more specific way of potentially treating the pain accompanied by migraines.
Will these treatments be the answer?
I don't think CGRPs are the end-all-be-all treatment. Although pain is a major component of a migraineur's disability, in my years of living with migraines and treating patients, I have found that the sensory component associated with migraines is most disabling. I rediscovered this the other day when I went out to eat and almost died from the bright lights and loud noises in the restaurant. This sensory phenomena tend to originate outside the trigeminal nerve, however.
Moreover, the current medications being evaluated by the FDA are all subcutaneous except one, which is intravenous injection. In my practice, I found patients to be reluctant to use injections except as last resort. Having said this, injectable Imitrex is still the fastest-acting and most effective treatment for migraines to date yet it is not widely prescribed nor used by patients who prefer oral compounds. There is an oral form of CGRP currently being tested in clinical trials.
What does that mean for the future?
Although, there is talk about a 20% of chronic migraines improvement with CGRP - this astonishing finding needs to be replicated in a larger population.
Further, we don't know what the effects of these circulating antibodies will have on the female patient's reproductive system - since women are at greater risk. Not to mention the cost and availability.
Will these substances change the landscape of migraine treatment – no doubt? But will it single-handedly eradicate all migraine or improve the life of all migraineurs? Highly unlikely. It will nonetheless provide a new armamentarium with which to combat migraines- a welcome addition to the treatment of a complex disease.
My dark room: