St. Jude Medical Inc's implantable device reduced the number of debilitating migraine headaches in a clinical study, the company said on Thursday, but analysts said the results were not strong enough to win U.S. regulatory approval.
The company said it was not yet clear when the device would get U.S. Food and Drug Administration approval for the treatment of chronic migraine.
The device is currently available in Europe to treat chronic pain.
A migraine headache is a disabling condition that can last for hours or days at a time and for which there are few treatments. Last year, the FDA approved injectable anti-wrinkle drug Botox to treat migraines.
The St. Jude system takes a different approach. It works by delivering mild electrical pulses from the implanted device, much like a pacemaker, to leads placed under the skin at the back of the head, with pulses stimulating the occipital nerves.
Results from the 157-patient study, presented at the International Headache Congress in Berlin, showed a statistically significant improvement in the number of headache days per month and improvement in quality of life.
The St. Jude-funded study -- the largest of its kind -- followed patients who suffered 26 headaches per month on average. Participants were implanted with the company's Genesis neurostimulator and randomly assigned to an active or control group for 12 weeks.
The active group got stimulation immediately, while the control group did not receive stimulation until after the first 12 weeks. After one year, 66 percent of patients reported excellent or good pain relief, St. Jude said.
Patients who received stimulation reported a 28 percent decrease in their number of headache days, or 7 fewer days per month, compared with the placebo group, which reported a 4 percent decrease, or 1 fewer day per month.
At 12 weeks, 53 percent of patients in the active group ranked their relief as excellent or good, compared with 17 percent in the placebo group.
St. Jude has filed for CE Mark approval of the Genesis neurostimulation system for the management of pain and disability associated with chronic migraine and expects to begin a limited introduction in Europe later this year.
About 10 percent of adults worldwide suffer from migraine, according to the World Health Organization. The condition affects almost 28 million Americans, or roughly 13 percent of the population, according to the National Headache Foundation.
"The chronic migraine market represents a large area of unmet medical need, and St. Jude is well positioned to capture a first-mover advantage in this potentially meaningful new market opportunity," JPMorgan analyst Michael Weinstein wrote in a research note.
St. Jude rival Medtronic Inc said it continued to explore the use of neurostimulation technology for the treatment of chronic migraine headaches.
"We completed our feasibility study for occipital nerve stimulation therapy for chronic migraine and we're applying what we learned as we determine next steps for our pivotal trial," a spokeswoman said. "However, at this time, it's premature to disclose our plans or discuss timelines."
Shares of St. Jude were down 3.5 percent at $46.96 on the New York Stock Exchange.