In a study, the company says its system gives patients better control over involuntary shaking.
An approach known as deep brain stimulation significantly improves Parkinson's disease patients' control over their symptoms and motor function, including better control over the involuntary shaking often brought on by Parkinson's medication, a study by St. Jude Medical Inc. has found.
The Little Canada-based company's study looked at 136 patients who were implanted with St. Jude's Libra and LibraXP deep brain stimulation systems. It compared two groups: a control group that had the device implanted but did not receive an electrical current into the brain for the first three months and another group that received stimulation throughout the study.
Patients in the stimulation group averaged an increase of 4.27 hours of "on time" -- or good control over their symptoms -- compared with an increase of 1.77 hours in the group without stimulation. In addition, patients reported an overall improvement in their quality of life.
"These results are important as they represent the first large, randomized, controlled study of a constant current device for managing the symptoms of Parkinson's disease," said Dr. Michael S. Okun, administrative director of the University of Florida College of Medicine's Center for Movement Disorders and Neurorestoration and the primary author of the article.
The neurostimulators evaluated in the study are approved for use in Europe, Latin America and Australia. The systems use a battery-powered device that is surgically implanted and generates mild electrical pulses. Wires carry those impulses to a targeted area in the brain.
More than 1 million people in the United States now have Parkinson's disease, according to the National Parkinson Foundation, with another 50,000 to 60,000 new cases diagnosed each year. About 6 million people worldwide suffer from Parkinson's.
The study was conducted at 15 medical centers in the United States. Additional key findings at three months were as follows:
• Patients receiving stimulation had a 73 percent response rate -- at least a two-hour increase in "on time" -- compared with a 38 percent response rate in the group without stimulation.
• Motor scores for those in the stimulation group improved 39 percent compared with the baseline as measured by the Unified Parkinson's Disease Rating Scale.
• There was a statistically significant decrease in the amount of medication needed to control symptoms in the stimulation group compared to the group without stimulation.
Participants in the stimulation group did see an increase of slurred speech and fatigue. Five patients contracted infection after implantation.
Study results were for patients after three months in the study. Study participants have passed the one-year mark of the study and more results are expected to be released later. Patients will be followed for another five years to see the long-term effects of deep brain stimulation on a disease that gets progressively worse.
"We went into this study expecting good results, and what we got out of it really validates the therapy and just adds more depth to the literature on the effects of deep brain stimulation on Parkinson's disease symptoms," said Rohan Hoare, president of St. Jude's neuromodulation division.
More than 75,000 St. Jude Medical neurostimulation devices have been implanted in patients around the world. St. Jude also is conducting clinical studies for depression and essential tremor. In September, it won approval in Europe to use neuromodulation in the treatment of chronic migraines.
Rick Wise, an analyst with Leerink Swan Research, called deep brain stimulation for Parkinson's "a relatively small product line in the context of STJ's overall portfolio. But, once launched in the U.S., revenues will be incremental -- hence creating another potential, albeit smaller, growth driver for STJ."
Wise said that St. Jude will use this study to apply for U.S. approval of neurostimulation for the treatment of Parkinson's.
Hoare, however, would not say when that might happen.
Results of the study were published online Wednesday in the Lancet Neurology journal. (www.thelancet.com/journals/laneur/onlinefirst)
James Walsh • 612-673-7428