2025 American Academy of Neurology Abstract Website

Objective:

The INTREPID study had two phases: a double-blind, sham-controlled, multicenter, randomized efficacy phase followed by an open-label phase. Here, we present outcomes from the 5-year open-label phase evaluating long-term effectiveness of subthalamic nucleus (STN) deep brain stimulation (DBS).

Background:

DBS is widely recognized as a highly effective therapy for improving motor function and quality-of- life in patients with moderate to severe Parkinson’s disease (PD). The INTREPID study was designed to provide class I evidence for the use of STN-DBS in the control of PD motor symptoms and to evaluate efficacy of a novel multiple independent constant current-controlled DBS device.

Design/Methods:

During the open label phase, subjects returned to the clinic for evaluation and programming at 20-, 26-, 48-, 52-, 78-weeks, 2-, 3-, 4-, 5-Year post-DBS randomization. Evaluated efficacy outcomes included but were not limited to UPDRS I-IV in meds ON and OFF condition, PDQ-39, and treatment satisfaction. Additionally, individual motor symptoms (assessed by parts of UPDRS III) were also analyzed per the following: rigidity, bradykinesia, and tremor (rest and postural).

Results:

Significant improvements were observed in UPDRS III scores (meds off), with motor function improvement by 51% at Year 1, and remained improved by 36% by Year 5. Furthermore, analysis of UDPRS III (meds off) sub-categories showed sustained improvement in tremor, rigidity, bradykinesia. UPDRS II scores showed a 40% improvement in activities of daily living compared to screening at Year 1, decreasing to 20% improvement by Year 5.

Conclusions:

This 5-year data demonstrates that STN-DBS provides significant and sustained improvements in motor function and activities of daily living. Patient satisfaction with treatment remained high throughout the study and safety outcomes were consistent with previously reported trials. Collectively, these findings support use of subthalamic DBS in patients with moderate to advanced PD who no longer achieve adequate symptom control with medications alone.