CGRP Antagonists are the New Triptans
The American Headache Society (AHS) held its 57th Annual Conference in June 2015 in Washington, DC. The buzzword this year was CGRP, which stands for Calcitonin Gene-Related Peptide. A peptide is a molecule consisting of two or more amino acids. CGRP has 37 amino acids and is produced in the peripheral and central neurons. Most importantly, the function of CGRP is to transmit pain.
The last time a drug came out that was specifically targeted for Migraine relief was in the early 1990s when triptans were introduced in the market. Maxalt, Relpax, Imitrex, Zomig are all in the triptan class of drugs and are now household names. Triptans help a large population of Migraineurs when taken at the onset of an attack.
CGRP antagonist drugs are being designed as a preventative, not an abortive like triptans. These new drugs contain human monoclonal anti-bodies that blocks the CGRP receptor. Reducing elevated levels of CGRP is believed to reduce or prevent pain. If these drugs pass through FDA approval, they would be the first treatment to ever prevent Migraines.
Patients currently have many options to take on a daily basis to prevent attacks, but all of these drugs were originally designed to help a different population of patients. Anticonvulsants (like Depakote and Topamax) were created to help Epileptic patients. Anti-depressants (like Zoloft and Effexor) are used widely for Migraineurs, but clearly were intended to help those with depression. Calcium channel blockers (like Verapamil) is a medicine used to control high blood pressure. Beta Blockers (like Inderal) are also used to treat hypertension.
Over time, doctors found that using these drugs off-label for Migraine patients had a positive effect on Migraine prevention. The possibility of a new drug designed specifically to prevent Migraines is very exciting news. Unfortunately, it may still be a few years away before you can get your hands on one of them.
Status of current trials
There were three pharmaceutical companies on hand at the AHS conference to discuss their clinical trials testing their new CGRP antagonist drugs; Amgen Pharmaceuticals, Eli Lilly and Company and Teva Pharmaceuticals. The main purpose of all of the medications was to see a reduction in the number of Migraine days per month. All three companies are in Phase II trials of their drugs.
Each study administered their anti-CGRP drug via intramuscular injection at varying doses versus a placebo. Participants were considered episodic Migraineurs, having between four and 14 Migraine days per month or eight and 14 Migraines days per month for the Teva Pharmaceutical drug. Each study had between 200 and 500 participants. In the Teva Pharmaceutical trial, patients were allowed to stay on their current medication regimen to prevent or abort Migraines. It is unknown whether the other two trials allowed the same.
Exciting news for the migraine community
All three studies study reached their primary endpoint of reducing the number of headache days as compared to the participant’s baseline prior to administration of the drug. Specifically, Amgen Pharmaceuticals trial saw that after 12 weeks of use, 46.5% of participants in the highest dose category of 70mg, had an overall reduction in the amount of Migraine days per month. The average reduction in Migraine days was 3.4 days per month for these study participants.
This is extremely exciting news for the Migraine community. Each pharmaceutical company still has to complete additional studies before obtaining FDA approval, a task which could take another 1-3 years. Having an antagonist CGRP medication would be the first time a drug has been specifically made for the prevention of Migraine headaches. This is a huge win for Migraineurs!
For more in-depth study information, please see:
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