By Amy Norton
TUESDAY, April 22, 2014 (HealthDay News) -- Two experimental drugs may help prevent migraines in people who suffer multiple attacks a month, according to preliminary findings from a pair of clinical trials.
The drugs, one given by IV and one by injection, are part of a new approach to preventing migraine headaches. They are "monoclonal antibodies" that target a tiny protein called the calcitonin gene-related peptide (CGRP) -- which recent research has implicated in triggering migraine pain.
In one study, patients saw a 66 percent reduction in their migraine attacks five to eight weeks after a single dose of the IV drug -- known for now as ALD403. That compared with a 52 percent decrease among patients who were given a placebo, or inactive, infusion.
In the other trial, patients receiving the injection drug saw a similar benefit from three months' worth of biweekly treatments.
The findings, scheduled to be presented Tuesday at the American Academy of Neurology's annual meeting in Philadelphia, are preliminary. And experts stressed that many questions remain.
Still, migraine sufferers can "take heart" that new drugs, specific to the pain condition, are under development, said Dr. Peter Goadsby, a neurologist at the University of California, San Francisco, who worked on both studies.
Right now, he said, the drugs used to prevent migraines are all older medications that were originally developed to treat other conditions. They include certain antidepressants, high blood pressure medications and anti-seizure drugs.
In contrast, the experimental medications aimed at CGRP are the first "designer drugs" for preventing migraine, said Dr. Richard Lipton, a headache expert who was not involved in the studies.
These early findings are "very encouraging," said Lipton, who directs the Montefiore Headache Center in New York City. "To me, this proves the concept that targeting CGRP can be effective," he said.
However, larger, longer-term studies are still needed to confirm the drugs' effectiveness and safety, Lipton and Goadsby said.
The trial testing ALD403, the IV drug, included 163 patients who were randomly assigned to receive either a single dose of the drug or a placebo infusion. Before treatment, all of the patients were suffering migraines five to 14 days out of every month.
Five to eight weeks later, patients given the drug were having 5.6 fewer "migraine days" per month on average -- a 66 percent drop. The placebo group also saw an improvement, of 4.6 fewer migraine days. Still, the benefit of the drug was significant in statistical terms, Lipton pointed out.
In the other trial, 217 patients received either the injection drug -- by the name of LY2951742 -- or a placebo, biweekly for 12 weeks.
Again, both groups got some migraine relief, but the benefit was bigger for patients on the real drug. They had 4.2 fewer migraine days a month, or a 63 percent decline. The placebo patients had three fewer migraine days, or a 42 percent decrease.
Some big questions remain, however. Researchers have to figure out how long the effects of the medications last, and how often they would need to be given, Goadsby said.
In the short term, the drugs seemed "well tolerated," Lipton said. People in the injection-drug trial had higher rates of abdominal pain and respiratory infections than the placebo group. And in the IV-drug study, people on the real drug had no more side effects than the placebo group.
Still, Lipton said, "a lot more people need to be followed to prove [the drugs'] safety."
He acknowledged that some patients might balk at the idea of an IV drug, which would have to be given by a doctor. An injection drug might be more acceptable, he said.
About 12 percent of Americans suffer migraine headaches, according to the U.S. National Institutes of Health. Many of them can manage with pain relievers, but about one-third need preventive medication, Lipton said.
However, he added, only around 10 percent take preventive drugs, often because they don't work or the side effects are intolerable. "There's a huge need for new preventive medications," Lipton said.
The current studies were funded by Alder Biopharmaceuticals, which is developing ALD403, and Arteaus Therapeutics, the developer of LY2951742.
Research presented at meetings should be viewed as preliminary until published in a peer-reviewed medical journal.