Long-Term Safety of MR-Guided Focused Ultrasound Thalamotomy in Essential Tremor and Parkinson’s Disease: Updated Evidence from Clinical Trials and Real-World Data
Lindsay Knight1, Ian Pyle1, Regina Martuscello1, Angeles Sanchez Fraga1, Gilat Schiff2, Amit Sokolov2, Mark Grassman3, Cyril Ferrer1, Katie Gant1, Augusto Grinspan4
1Medical Affairs, Insightec, Inc., 2Treatment Interventions Affairs, 3Clinical Affairs, Insightec, Inc., 4Medical Affairs, Treatment Interventions Affairs, Insightec, Inc.
Objective:

To update the long-term safety profile of MR-guided focused ultrasound (MRgFUS) for medication-refractory essential tremor (ET) and Parkinson’s disease (PD), incorporating clinical trial and real-world data sources.

Background:

MRgFUS is FDA-approved for the unilateral and staged, bilateral treatment of ET and PD. Over 25,000 procedures have been performed globally. Both clinical trial and real-world data demonstrate immediate and sustained symptom improvement, with most adverse events (AEs) being mild and transient.

Design/Methods:

Reviewed and compared long-term safety outcomes from pivotal clinical trials (ET thalamotomy [ET-T], recently published ET continued access study [ET-CA], ET staged, bilateral [ET-SB], Parkinson’s disease thalamotomy [PD-T], Parkinson’s disease pallidotomy [PD-P]) and real-world sources including published literature and post-market surveillance (PMS) data.

Results:

Across pivotal trials, most AEs were generally mild (74% ET-T; 85% ET-CA; 85% ET-SB; 72% PD-T; 75% PD-P). Related severe events were rare. The most common treatment-related AEs in thalamotomy procedures were paresthesias (38% ET-T; 34% ET-CA; 33% ET-SB; 25% PD-T) and gait disturbance (36% ET-T; 38% ET-CA; 24% ET-SB; 45% PD-T), with dysarthria more frequent after staged, bilateral MRgFUS (2% ET-T; 12% ET-CA; 24% ET-SB). In pallidotomy treatments, the most common AEs were dysarthria, gait disturbance, and loss of taste (2.9% each). Many AEs resolved within 6 months, and no new or worsening AEs were seen at longer-term follow-up. No declines in cognition have been reported in ET or PD. Literature indicates similar safety, with mostly mild and transient events; two recent case reports describe isolated and rare hemorrhages. The most recent PMS data indicate AEs were reported in 0.41% of 6997 clinical procedures.

Conclusions:

Unilateral and staged, bilateral MRgFUS continues to demonstrate a favorable safety profile in ET and PD. Ongoing surveillance is essential to identify rare events, but overall, MRgFUS remains a safe and well-tolerated treatment option in clinical practice. 

10.1212/WNL.0000000000217610
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