Wsj.com reporter Jonathan D. Rockoff reports on new medicines, now in late stages of development for migraine pain…
Researchers are unlocking some of the mysteries surrounding migraines, raising hopes for a new class of treatments.
Millions of patients who experience migraines would benefit from better medicines, researchers say. Drugs taken to treat debilitating headaches don’t work in all patients. Meanwhile, drugs taken to prevent attacks were developed to fight other conditions, like high blood pressure, and have limited effectiveness.
Today, several companies are in the late stages of testing a new class of migraine drug. These drugs target a chemical known by its initials, CGRP, that researchers have found is involved in the brain’s pain-signaling during migraines.
“Finally a new era seems to be emerging,” says David Dodick, director of the migraine program at the Mayo Clinic in Arizona, president of the International Headache Society and chairman of the American Migraine Foundation.
“We know enough about the biology and what’s happening in the brain during an attack that some new medicines are being specifically developed for migraines,” Dr. Dodick says.
New drug discovery was hindered for years by a lack of understanding about the causes of migraines. The prevailing wisdom had long been that they were the result of a widening of blood vessels in the brain. More recently, research has indicated migraines are actually a neurological disorder in which pain and sensory networks in the brain are activated and healthy pain signaling goes haywire.
Researchers have now identified some genes that play important roles in many patients. They are studying migraines both in mice engineered to have attacks and in humans, using the latest brain-imaging technology, says Peter Goadsby, who worked on research that led to the 1990 publication of research identifying the role of CGRP in migraines.
CGRP, which stands for calcitonin gene-related peptide, is a small protein found at the ends of nerves and embedded in blood vessels throughout the body; its release helps dilate, or widen blood vessels and generally signals pain when it is released into the blood or between nerves. Research found it can trigger migraines in particular when given to certain patients, says Dr. Goadsby, director of the NIHR-Wellcome Trust Kings Clinical Research Facility at Kings College London and neurology professor at the University of California, San Francisco.
Alder BioPharmaceuticals Inc., Amgen Inc., Eli Lilly & Co. and Teva Pharmaceutical Industries Ltd. are in the late stages of testing their injections. Allergan Inc., which sells Botox for treatment of chronic migraines, is working on CGRP-blocking pills that the company says were designed to reduce the risk of liver side effects.
All of the companies say they haven’t seen any signs of safety problems so far in their clinical testing. “The available evidence suggests the liver toxicity is not a consequence of intervening on CGRP,” but rather an “idiosyncratic response to a specific molecule,” says Richard Lipton, a professor of neurology at Albert Einstein College of Medicine.
Elizabeth Loder, head of the headache division in the department of neurology at Brigham and Women’s Hospital in Boston and former president of the American Headache Society, expects the CGRP-blocking drugs would improve treatment for many patients if they continue to work safely in clinical testing and win approval. The new drugs probably won’t stop all attacks or help all patients, though, she cautions.