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Is the treatment available only in
the United States?
The United States is the first country to get the first anti-CGR-
Preceptor monoclonal antibody, and we are the only country
that has erenumab available.
Why is this so groundbreaking
for migraine patients?
We’ve never had preventive medication designed for migraine
in our lifetime. We’ve never had preventive medicines that are
very, very well tolerated. All of our current preventive medicines
have side effects that often prevent people from using
them. We’ve never had preventive medicines that kick in and
give significant clinical benefit within a month. If you add all
of that up, this really seems like a watershed moment.
I really feel like the ground is shaking under our feet. I feel like
this is a time when prevention and the way we treat migraine
is about to change for the better, and I’m extremely happy for
people with migraine across the country at this time.
What’s next?
If you think you may be a candidate for this new type of migraine
medication, talk with your doctor, and perhaps ask for a
consult with a neurologist or headache specialist who can help
you understand more about the medication. Monoclonal antibody
therapy is expensive, and there will likely be regulations
about for whom s the treatments are appropriate. Much more
research needs to be done about who is the best candidate for
this therapy. But for many migraine patients who have not responded
to the standard treatments, or who have had intolerable
side effects such as cognitive dysfunction, low blood pressure,
weight loss or gain, or other issues, CGRP monoclonal
antibodies are safe and well tolerated, and are an exciting new
development for migraine therapies.
Monoclonal antibodies target either CGRP or the CGRP receptor
and are used for migraine prevention. A monoclonal
antibody is a collection of identical proteins that have been
developed to only target one substance in the body. They are
given by injection subcutaneously (under the skin), to avoid
degradation by the stomach. Because they are large molecules,
they take longer to start working and work in the lining of the
brain rather than in the brain itself. They also tend to have
few drug interactions and are unlikely to cause liver or kidney
damage. Currently, three CGRP inhibitors that are monoclonal
antibodies have been approved:
⚛ Aimovig (erenumab-aooe): Approved May 17, 2018
⚛ Ajovy (fremanezumab): Approved Sept 14, 2018
⚛ Emgality (galcanezumab-gnlm): Approved Sept 27, 2018
⚛ Eptinezumab: Not yet approved.
Gepants are small molecule drugs which block the CGRP receptor
and are still being investigated for both migraine relief
and prevention. Unlike monoclonal antibodies, gepants
rapidly penetrate the brain so work quickly; however, they are
metabolized in the liver so there is a higher potential for interactions
and possibly liver damage. Examples include ubrogepant,
atogepant, and rimegepant.
CGRP inhibitors are the first drugs to be developed specifically
for migraine prevention. All other migraine preventive agents
were originally developed for other conditions (such as high
blood pressure), and then found later by chance to have an
effect in migraine.
Once it was determined that CGRP caused migraine, it became
clear that if we could do something to stop CGRP, we
could probably stop migraine. Four companies decided to
create antibodies against CGRP and against the receptor to
which CGRP binds. These large molecules are called monoclonal
antibodies, and they do not cross into the brain. They
are not eliminated by the liver. In fact, they are such big molecules
that they have to be injected to get into the system. The
drug approved last week, which is called erenumab, the brand
name of which is Aimovig, is a monoclonal antibody against
the CGRP receptor.
For more information on the new anti CGRP treatments,
please contact your healthcare professional. ⚛
IN REVIEW
⚛ Multiple studies have confirmed that release of
calcitonin gene-related peptide (CGRP) is increased
during acute migraine attacks.
⚛ In the trigeminal ganglion, CGRP is expressed in
C-fibres and its receptor is expressed in Aδ-fibres;
these types of fibres are involved in different aspects
of pain perception.
⚛ The trigeminal ganglion is central to the trigeminovascular
reflex, which is triggered to protect against
vasoconstriction; triggering of this system in patients
with migraine leads to the perception of pain.
⚛ The trigeminal ganglion and dura are not behind
the blood–brain barrier; therefore, they are likely
to be the targets of gepants and antibodies in
migraine treatment.
⚛ CGRP receptor antagonists, anti-CGRP antibodies
and anti-CGRP receptor antibodies have proved
effective for migraine pain relief, strongly supporting
the hypothesis that CGRP has a major role in
migraine pathophysiology.
"CGRP is the most potent
vasodilator of human cerebral
arteries."
Frederick R. Taylor, MD, Adjunct
Professor of Neurology at Minnesota
University in Minneapolis.
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