CGRP-blocking migraine drug, but the company’s compound never advanced past mid-stage studies. Merck (NYSE: [[ticker:MRK]]) also developed CGRP drugs for migraine, but stopped work on them after Phase 2 results showed liver problems.
Amgen’s drug erenumab (Amovig) is a once-a-month subcutaneous injection. In Phase 3 studies lasting six months, patients experienced a 50 percent reduction in the number of migraines per month compared to patients given a placebo.
Triptans, the last new class of migraine treatments, were approved in the 1990s. Taken at the onset of pain, they reduce inflammation and constrict blood vessels to relieve symptoms. They do not work for everyone, and they do not prevent migraines from starting.
FDA-approved therapies for prevention are available, though none were developed specifically for the condition. Divalproex sodium (Depakote), initially approved in 1983 to treat epilepsy and later, bipolar disorder, is one such drug, as is the anti-seizure topiramate (Topamax). Beta blockers, a class of drugs for high blood pressure, have also gained additional approvals for migraine prevention. Botulinum toxin (Botox) injections offer yet another alternative, though the FDA has approved this therapy only for chronic migraine, defined as 15 or more headaches per month.
These drugs come with risky side effects, including nausea, fatigue, weight gain or loss, depression, and birth defects. They also take a while to kick in. Patients may need two or three Botox injections before they see any benefit, says Deena Kuruvilla, a neurology professor at Yale University. Anti-seizure and blood pressure drugs can take six to eight weeks to work.
“That’s a long time to be disabled by a migraine,” Kuruvilla says. “Our patients have to get back to work, get back to school.”
ASSESSING THE DATA
In clinical trials, all four of the new CGRP antibodies have produced relatively mild side effects, such as redness at the injection site. One of the lingering concerns has been cardiovascular risks posed by the drug. Those concerns appear to be eased by preliminary data Lilly released this week from a Phase 3 study testing its drug in episodic cluster headaches. Patients with cluster headaches tend to have greater heart risks, RBC Capital Markets analyst Brian Abrahams wrote in a research note. That no such problems were observed in the Lilly study offers “additional reassurance on safety for the CGRP class,” he added.
What’s more, these drugs also appear to have the advantage of working quickly. Kuruvilla notes that clinical trial results showed patients responded quickly to CGRP treatment. A subset of “super responders” who saw a benefit even faster would be particularly suited for CGRP therapy, says Wade Cooper, a neurology professor at the University of Michigan at Ann Arbor. The problem is, drug companies don’t yet know how to identify them ahead of time.
ICER’s analysis follows similar observations that CGRP treatment won’t be appropriate for all patients. Yale’s Kuruvilla says they’ll likely become one of many choices, perhaps as part of combinations, to treat patients. Patients could take a CGRP drug for prevention, she says, but when they need immediate treatment for an attack, triptans would offer an option, she says. Cooper says more options will help more patients.
“It’s such a different approach to treating migraine than we’ve had before, and the hope is it will help people that haven’t responded to other treatments,” he says.
Photo by Flickr user r.nial bradshaw via a Creative Commons license
