The FDA has okayed a in patients who haven't responded to other medical therapy, the agency announced.
The device, made by Dallas-based company , uses MRI guidance to deliver focused ultrasound into the thalamus, the area of the brain thought to be responsible for tremor. The focused sound waves destroy tissue in this region in an attempt to stop tremor.
This is not the first focused ultrasound device approved by the FDA. is already approved to treat uterine fibroids, and in 2015, FDA gave the green light to EDAP TMS' high-intensity focused ultrasound device Ablatherm .
Advocacy efforts around focused ultrasound have intensified in recent years -- the latest being a short story by bestselling author John Grisham about the device's benefits. Grisham is on the board of the Focused Ultrasound Foundation. His neighbor, , a professor of neurosurgery at the University of Virginia in Charlottesville, is the foundation chairman.
The FDA said it based its decision on a single double-blind controlled trial of 76 patients with essential tremor who didn't respond to medications.
Full data from the trial were not available. An FDA spokesperson said the Premarket Authorization (PMA) packet with that information would be posted to the agency’s website within a few weeks. Device maker InSightec did not return a phone call as of press time.
A total of 56 patients were treated with the device, and 20 received a sham treatment. Those in the placebo group were allowed to cross over into treatment after 3 months.
Overall, researchers found that those who had the focused treatment had a 50% improvement in tremor and motor function 3 months after treatment compared with baseline. After 1 year, patients retained a 40% improvement over baseline.
Patients in the control group had no improvement, and some had worsening after the sham procedure, FDA said.
Adverse events included numbness/tingling of the fingers, headache, imbalance/unsteadiness, loss of control of body movements, or gait disturbance. Other side effects that were thought to be possibly related to treatment included tissue damage in an area other than the treatment area, hemorrhage in the treated area requiring emergency treatment, skin burns with ulceration of the skin, skin retraction and scar formation, and blood clots, FDA said.
ExAblate is contraindicated in pregnant women, in those with advanced kidney disease or on dialysis, patients with unstable heart conditions or severe hypertension, those with any substance abuse behaviors, and patients with a history of abnormal bleeding, hemorrhage, and blood clotting disorders. It is also contraindicated for patients who can't have an MRI such as those with a cardiac pacemaker.
And the device is not for patients currently on anticoagulants or other drugs known to increase hemorrhage risk, for patients with a history of strokes or brain tumors, and those not able to tolerate a prolonged stationary position during treatment.
Disclosures
Kassell disclosed owning shares in InSightec.