The Food and Drug Administration has for the first time approved the use of an MRI-guided focused ultrasound system to treat cancer pain from bone metastases. This is the second FDA approval for the ExAblate system, which was approved in 2004 for treatment of uterine fibroids.
“The recent FDA approval of ExAblate for pain palliation will offer new options for cancer patients with crippling bone pain who are seeking pain-management options and are no longer eligible for radiation treatment,” said Dr. Kobi Vortman, President and CEO of InSightec, the Israeli manufacturer of ExAblate.
Focused ultrasound surgery is already approved for treatment of bone metastases in Europe. The procedure uses magnetic resonance imaging (MRI) to guide a focused beam of acoustic energy through the patient’s skin, muscles and tissue to heat the targeted bone area. The increase in temperature destroys the periosteum, which contains the pain-reporting nerve fibers.
Bone metastases occur when cancer cells break away from their primary site and spread to other parts of the body. Tumors that spread to the bone can be very painful. Current treatment options include radiation, surgery and various prescription painkillers. Up to 30% of patients with bone metastases either do not respond to radiation therapy or are unable to undergo radiation for pain relief.
“Pain is the most common and severe symptom of bone metastases, often causing significant physical and emotional discomfort with a large impact on enjoyment of life,” says Mark Hurwitz, MD, who led the international clinical study that formed the basis of InSightec’s application to the FDA. “Results from the clinical study showed that ExAblate therapy significantly reduces pain caused by bone metastases. Patients also reported lasting improvement in well-being and function, along with a decrease in the need for medication.”
Over two-thirds of breast and prostate cancers that metastasize spread to the bones, according to the American Cancer Society. Bone metastases also occurs in up to 30% of metastatic lung, bladder and thyroid cancers.
FDA approval of ExAblate was based on the results of a randomized clinical study comparing patients with painful bone metastases undergoing palliative therapy with ExAblate to a similar group undergoing a placebo therapy. Patients who underwent the ExAblate therapy reported clinically significant pain relief and improved quality-of-life three months after treatment.
Twenty hospitals in Europe and Asia-Pacific already offer ExAblate as a palliative therapy for bone metastases.
Focused ultrasound surgery is a relatively new medical technology being developed to treat cancer and other diseases. In the U.S. it is still only approved as therapy for uterine fibroids and pain from bone metastases; but trials are underway for its use in the treatment of breast, brain, prostate and liver tumors.
Studies for stroke, epilepsy, pancreatic tumors and kidney tumors are in the planning stages.
When further refined, advocates say focused ultrasound could also be used to deliver drug payloads directly to a diseased area. Antibiotics, chemotherapy drugs and other medication would be shipped via ultrasound in nanoparticles smaller than red blood cells to wherever they’re needed in the body.