BALTIMORE – The use of subthalamic nucleus deep brain stimulation (DBS) along with optimal drug therapy in patients with early stage Parkinson’s disease produced clinically meaningful improvements in clinician-assessed motor control that lasted at least 5 years in a prospective pilot study.
If the findings bear out a phase III trial that has been approved, DBS may become a valuable method to achieve long-term improvement in motor skills in patients with Parkinson’s disease.
The pilot trial involved 30 patients with Parkinson’s disease, aged 50-75 years, and demonstrated the safety and benefit of DBS in conjunction with optimal drug therapy (ODT) – involving drugs such as carbidopa/levodopa, pramipexole, ropinirole, and selegiline – compared with ODT alone in improving motor scores of the patients through 2 years (Parkinsonism Relat Disord. 2014. 20[7]:731-7). The latest subanalysis of the trial data took a longer look, examining the effect of DBS through 5 years.
The subanalysis involved 28 patients; 14 in the DBS plus ODT group and 14 in the ODT-only group. Both groups were predominantly male and were similar in age at baseline (about 61 years). Motor control was assessed during the periods when DBS was applied and not applied by using the Unified Parkinson’s Disease Rating Scale (UPDRS) Part III (clinician assessed) and the Hoehn and Yahr scale.
Over the 5-year period, mean UPDRS motor scores progressively worsened for the ODT group but improved for patients receiving DBS. Patients who received DBS plus ODT had improvements relative to the ODT-only patients of 4.6 points at 1.5 years, 5.8 points at 2 years, 8.9 points at 4 years, and 10.1 points at 5 years.
“These results demonstrate that subthalamic nucleus deep brain stimulation applied in early-stage Parkinson’s disease may provide long-term, clinically meaningful improvement in motor function over standard clinical therapy,” Dr. Hacker said.
The exact mechanism of DBS is still unknown. But, there is evidence that synaptic plasticity is involved. Dr. Hacker speculated that in early Parkinson’s, the DBS intervention comes at a time of relative neuronal stability, which is then maintained.
The results of the pilot trial led to Food and Drug Administration approval of a large-scale, multicenter clinical trial. All participants will be implanted with a DBS device and will receive ODT. Some of the subjects will be randomized to receive DBS during the first 2 years, along with ODT, with the remainder receiving ODT only. In the next 2 years, all subjects will receive DBS and ODT.
Funding was provided by the National Center for Advancing Translational Science, the National Institutes of Health, Medtronic, and the Michael J. Fox Foundation for Parkinson’s Research. Dr. Hacker had no disclosures.