The drugs target a biochemical called calcitonin gene-related peptide (CGRP). The results from phase 2 clinical trials show that these drugs can effectively prevent migraine in a substantial portion of headache sufferers, according to the studies.
Two teams of researchers have been edging closer and closer in inventing a new class of drugs that can dramatically reduce chronic migraine by interrupting the chain of events thought to trigger the headaches.
“It’s very exciting, because this would be a form of prevention that might not have a lot of side effects and would be highly effective for people who have not had good treatment,” said Dr. Thomas Ward, a professor of neurology at Geisel School of Medicine at Dartmouth in New Hampshire. “The hope is these drugs will be clean, reduce the number of headaches people get, and won’t carry a lot of baggage.”
Findings from these studies were to be presented this week at the annual meeting of the American Headache Society, in Washington D.C.
Scientists have already known – for more than two decades that – CGRP plays an important role in migraine headaches, said Dr. Peter Goadsby, chair of the scientific program of the American Headache Society’s annual meeting and chief of the University of California, San Francisco Headache Center.
“This is the first time that migraine patients will get migraine drugs for prevention,” Goadsby said.
The body uses CGRP to control the opening of blood vessels, and it also is thought to play a role in the transmission of pain signals, Ward said.
“The last step in the pathway we think to setting off headache is this substance called CGRP,” Ward said. “This material is released by nerves, and when released it causes inflammation in the nervous system.”
Headache drugs called ‘triptans’ most commmonly used these days act by stopping migraines in progress – and they work by blocking CGRP, Ward said. But until now, researchers have been unable to come up with a way to prevent onset of migraines by targeting CGRP.
Traditional pharmaceuticals have not panned out in heading off migraines by blocking CGRP, Goadsby said. CGRP is widely used throughout the body, and blocking its function entirely can cause serious side effects in a number of organs.
This latest class of drugs reduces levels of CGRP through the use of monoclonal antibodies — laboratory-created antibodies that can be engineered to target any substance in the body.
These are the first drugs specifically developed for prevention of migraines, Goadsby said. Up to now, doctors have repurposed drugs developed for other health problems — for example, high blood pressure — to treat migraine.