WASHINGTON – An implantable device that stimulates the sphenopalatine ganglion nerve bundle either reduced or eliminated pain in 68% of more than 5,000 cluster headaches, a 3-year study has determined.
The device, which is approved in Europe, was more effective in attacks of moderate severity, with a 78% rate of pain reduction or elimination, Dr. Jose Miguel Lainez reported at the annual meeting of the American Academy of Neurology.
Courtesy Autonomic Technologies Inc.
The neurostimulator component of the Pulsante SPG Microstimulator System
The Pulsante System, manufactured by Autonomic Technologiesof Redwood City, Calif., consists of a neurostimulator about the size of an almond, and a lead with six electrodes. It’s inserted under local anesthetic via a small incision in the upper gum on the side in which the patient experiences symptoms. The electrodes are positioned along the sphenopalatine ganglion (SPG) nerve and the neurostimulator is affixed to the zygomatic process.
A hand-held remote controller placed against the cheek activates the device and controls the intensity of stimulation, which is thought to work by blocking signals to the postganglionic parasympathetic fibers. Those fibers innervate facial structures and the cerebral and meningeal blood vessels and are implicated in the pain and accompanying autonomic symptoms of a cluster headache attack.
Dr. Lainez, professor of neurology at Catholic University of Valencia (Spain), presented 3-year follow-up data from Pathway CH-1, a randomized, sham-controlled trial of 43 patients with cluster headache. Of these, 33 completed the 3-year follow-up period. Of the remaining 10, 1 was lost from observation, 5 violated protocol, 1 had the device implanted incorrectly, and 3 had the device explanted because of incorrect placement or lead migration.
Most of the patients were male. Mean age was 41 years. They had a mean disease duration of 10 years and averaged 17 cluster headaches per week but ranged from 4 to 70 attacks per week. Over the 3 years, 5,130 attacks were treated; the mean stimulation duration for these was 14 minutes with a mean response time of 11 minutes. Therapy was considered effective in 65% (3,354) of these attacks based on a clinically meaningful reduction in pain or pain elimination.
Dr. Lainez did not parse these results. However, in the initial 28-week phase of the Pathway CH-1 study, pain was reduced in 68% of attacks treated with the device and 7% of those treated with the sham control. Pain freedom by 15 minutes was achieved in 34% of attacks with full stimulation, compared with 1.5% of those treated with sham.
In the follow-up study, the device seemed most effective in attacks of moderate severity (78% response rate of pain reduction or elimination). The response rate was 59% in mild attacks and 51% in severe attacks. Most attacks treated with the device (77%) did not involve the use of abortive therapy.
Dr. Lainez did not mention adverse events related to the device. However, in the 28-week study, there were 92, including parasthesias and numbness; facial and tooth pain; and swelling. Others were considered mild and included dry eye, nose bleed, and facial asymmetry.
The device is currently being investigated in a U.S. study. The open-label Pathway-CH2 study aims to recruit 120 patients. For information on Pathway CH-2, contact Anthony Caparso.
The trial was sponsored by Autonomic Technologies Inc. Dr. Lainez had no financial ties with the company.
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