An interventional study of Unilateral Exablate MRgFUS Pallidothalamic Tractotomy and Staged Bilateral Exablate Pallidothalamic Tractotomy in Parkinson Disease, sponsored by InSightec. Not yet recruiting at 1 site in South Korea. Open to participants aged 30 Years and older. Per ClinicalTrials.gov, last updated 2026-11-06.
Sponsored by InSightec · Not applicable, Interventional, and Treatment
This study is a randomized clinical trial evaluating a focused ultrasound treatment for people with advanced Parkinson's disease (PD) who have disabling motor complications and symptoms.
The study uses the Exablate Neuro System, which delivers MR-guided Focused Ultrasound (MRgFUS). This technology focuses ultrasound energy on a specific brain target and generates heat to create a small lesion (ablation) without making a surgical incision.
The target in this study is the Pallidothalamic Tract (PTT), a pathway involved in the abnormal brain circuits that contribute to Parkinson's symptoms and complications.
This study is evaluating whether treating one side of the brain or treating both sides (in separate procedures) provides better outcomes for people with advanced Parkinson's disease who have motor complications and symptoms.
The main outcome measure is the change in the MDS-UPDRS Part III Upper/Lower Extremity (ULE) score at 3 months after first and second side treatment, compared with the respective control groups.
MDS-UPDRS Part III is a standard clinical scale used to assess Parkinson's motor symptoms. ULE score focuses on motor function in the arms and legs. Assessments are performed in the OFF-medication state, meaning Parkinson's medications are temporarily withheld so that the treatment effect can be measured more accurately.
In addition improvement in motor complications will be assessed with MDS-UPDRS Part IV and Patient diaries.
A Post Approval Study (US) / Pre Market Extension Study (Outside US), international prospective, multi-center, assessor-blinded, two-stage (2:1) randomized controlled trial evaluating successive Exablate treatment (first and second side) versus BMT (Best Medical Treatment).
In individuals eligible for the staged, bilateral Exablate PTT procedure, building on evidence from the predicate pivotal staged bilateral study that led to PMA approval in the United States, this trial aims to evaluate the successive treatment of 1st and 2nd side Exablate PTT ablation using a two-stage randomized controlled design. In Stage 1, patients will be randomized to receive either 1st side PTT procedure or best medical treatment (BMT). Patients who initially randomized to receive BMT will cross over to receive 1st side PTT procedure after 3 months (if they still qualify for the treatment). All patients will continue to be followed through a 6-month period post 1st side treatment. All eligible patients who reach Stage 2 will be re-randomized to undergo 2nd side PTT procedure or continue with BMT. Patients randomized to receive BMT in stage 2 will cross over to receive 2nd side PTT procedure after 3 months (if they still qualify for the treatment). All patients will continue to be followed through a 12-month period post 2nd side treatment. This design enables evaluation between staged-bilateral treatment, unilateral treatment alone, and standard of care (SOC)/BMT medical therapy. This study will generate real-world comparative data to better inform decision-makers about the generalizability in subthalamic region ablations involving the PTT. Outcomes will be assessed using relevant lateralized Parkinson-specific clinical scales, measures of functional impairment, disease-specific quality of life, adverse events, and patient-reported perceptions of overall treatment effectiveness.
4,573 studies on the registry are indexed under Parkinson Disease; 1,086 are open to participants now.
This study's planned enrollment of 120 is above the median of 40 across 3,353 interventional studies indexed under Parkinson Disease.
Browse Parkinson Disease studies →InSightec is the lead sponsor of 84 studies on the registry; 9 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Subject with severe premorbid risks as specified in the MDS-UPDRS Part II subsection motor aspects of experiences of daily living scores:
Subject who is in a nursing home in the last 30 days.
Additional Exclusion Criteria for Staged Bilateral procedure
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Short tests of memory and thinking, each scored out of 30. Lower scores suggest more difficulty; criteria give a range, either to include people with memory problems or to leave them out.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.
Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
MMSE and MoCA
Short tests of memory and thinking, each scored out of 30. Lower scores suggest more difficulty; criteria give a range, either to include people with memory problems or to leave them out.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
INR, PT and aPTT (clotting tests)
Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.
Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Subjects will undergo the 1st side Exablate procedure (\< 30 days after randomization) and will be followed for 6 months. At their Month 6 visit, subjects will have their re-baseline assessment and undergo staged randomization for the 2nd side treatment.
Device: Unilateral Exablate MRgFUS Pallidothalamic Tractotomy
Subjects will have their standard of care (SOC) treatment adjusted to best effect (BMT), and will be followed for 3 months. After their Month 3 visit, subjects will cross over to receive the 1st side treatment and be followed for 6 months. At their Month 6 visit, subjects will have their Treatment 2 re-baseline assessment and undergo staged randomization for the 2nd side treatment.
Drug: Best Medical Treatment (BMT)
Subjects will undergo the 2nd side Exablate procedure (\< 30 days after re-baseline assessment, and will be followed for 12 months.
Device: Unilateral Exablate MRgFUS Pallidothalamic Tractotomy · Device: Staged Bilateral Exablate Pallidothalamic Tractotomy
Subjects will continue with their SOC BMT and will be followed for 3 months. After their Month 3 visit, subjects will cross over to receive the 2nd side treatment and be followed for 12 months.
Device: Unilateral Exablate MRgFUS Pallidothalamic Tractotomy · Drug: Best Medical Treatment (BMT)
Subjects will be offered the option to receive best medical treatment and will be followed to capture natural disease progression at approximately the same time schedule as patients in the randomized groups (\~ every 3 - 6 months for up to 24 months).
Drug: Best Medical Treatment (BMT)
1st side Exablate MRgFUS Pallidothalamic Tractotomy for Parkinson's Disease
2nd side staged Exablate MRgFUS Pallidothalamic Tractotomy for Parkinson's Disease
Subjects will be managed according to conventional therapeutic guidelines (i.e., best medical treatment) for Parkinson's Disease
MDS-UPRDS Part III ULE score in the OFF-medication (unilateral treatment)
Between-group difference (Active Group 1 vs. Control Group 1) in the treatment effect (point change) in the MDS-UPRDS Part III ULE score in the OFF-medication state from Baseline to 3 month. This assessment will be performed by a Movement Disorders neurologist blinded to patient study group allocation.
Time frame: 3 Months
MDS-UPRDS Part III ULE score in the OFF-medication (bilateral treatment)
Between-group difference (Active Group 2 vs. Control Group 2) in the treatment effect (point change) in the MDS-UPRDS Part III ULE score in the OFF-medication state from Baseline to 3 month. This assessment will be performed by a Movement Disorders neurologist blinded to patient study group allocation.
Time frame: 3 Months
MDS-UPDRS III Total score in the OFF-medication state
Between-group comparison (Active Group 1 vs Control Group 1) of the treatment effect at Month 3 following Treatment 1 (unilateral) and within-group comparison (Active Group 1) of the treatment effect at all study visits (Month 1, 3 and 6) following Treatment 1 compared to baseline. Between-group comparison (Active Group 2 vs Control Group 2) of the treatment effect at Month 3 following Treatment 2 (staged bilateral) and within-group comparison (Active Group 2) of the treatment effect at all study visits (Month 1, 3, 6 and 12) following Treatment 2 compared to baseline.
Time frame: 1 Month, 3 Months, 6 Months, 12 Months
MDS-UPDRS Part III OFF ULE score
Between-group comparison (Active Group 1 vs Control Group 1) of the treatment effect at Month 3 following Treatment 1 (unilateral) and within-group comparison (Active Group 1) of the treatment effect at all study visits (Month 1, 3 and 6) following Treatment 1 compared to baseline. Between-group comparison (Active Group 2 vs Control Group 2) of the treatment effect at Month 3 following Treatment 2 (staged bilateral) and within-group comparison (Active Group 2) of the treatment effect at all study visits (Month 1, 3, 6 and 12) following Treatment 2 compared to baseline.
Time frame: 1 Month, 3 Months, 6 Months, 12 Months
MDS-UPDRS Part III ON Total score
Between-group comparison (Active Group 1 vs Control Group 1) of the treatment effect at Month 3 following Treatment 1 (unilateral) and within-group comparison (Active Group 1) of the treatment effect at all study visits (Month 1, 3 and 6) following Treatment 1 compared to baseline. Between-group comparison (Active Group 2 vs Control Group 2) of the treatment effect at Month 3 following Treatment 2 (staged bilateral) and within-group comparison (Active Group 2) of the treatment effect at all study visits (Month 1, 3, 6 and 12) following Treatment 2 compared to baseline.
Time frame: 1 Month, 3 Months, 6 Months, 12 Months
MDS-UPDRS Part IV Total score
Between-group comparison (Active Group 1 vs Control Group 1) of the treatment effect at Month 3 following Treatment 1 (unilateral) and within-group comparison (Active Group 1) of the treatment effect at all study visits (Month 1, 3 and 6) following Treatment 1 compared to baseline. Between-group comparison (Active Group 2 vs Control Group 2) of the treatment effect at Month 3 following Treatment 2 (staged bilateral) and within-group comparison (Active Group 2) of the treatment effect at all study visits (Month 1, 3, 6 and 12) following Treatment 2 compared to baseline.
Time frame: 1 Month, 3 Months, 6 Months, 12 Months
Number of hours per day in ON time without troublesome dyskinesia- as measured by patient diaries (unilateral)
Between-group comparison (Active Group 1 vs Control Group 1) of the treatment effect at Month 3 following Treatment 1 (unilateral) and within-group comparison (Active Group 1) of the treatment effect at all study visits (Month 1, 3 and 6) following Treatment 1 compared to baseline. Between-group comparison (Active Group 2 vs Control Group 2) of the treatment effect at Month 3 following Treatment 2 (staged bilateral) and within-group comparison (Active Group 2) of the treatment effect at all study visits (Month 1, 3, 6 and 12) following Treatment 2 compared to baseline.
Time frame: 1 Month, 3 Months, 6 Months, 12 Months
Number of hours per day in the OFF time as measured by patient diaries (unilateral)
Between-group comparison (Active Group 1 vs Control Group 1) of the treatment effect at Month 3 following Treatment 1 (unilateral) and within-group comparison (Active Group 1) of the treatment effect at all study visits (Month 1, 3 and 6) following Treatment 1 compared to baseline. Between-group comparison (Active Group 2 vs Control Group 2) of the treatment effect at Month 3 following Treatment 2 (staged bilateral) and within-group comparison (Active Group 2) of the treatment effect at all study visits (Month 1, 3, 6 and 12) following Treatment 2 compared to baseline.
Time frame: 1 Month, 3 Months, 6 Months, 12 Months
Number of hours per day with troublesome dyskinesia (unilateral)
Between-group comparison (Active Group 1 vs Control Group 1) of the treatment effect at Month 3 following Treatment 1 (unilateral) and within-group comparison (Active Group 1) of the treatment effect at all study visits (Month 1, 3 and 6) following Treatment 1 compared to baseline. Between-group comparison (Active Group 2 vs Control Group 2) of the treatment effect at Month 3 following Treatment 2 (staged bilateral) and within-group comparison (Active Group 2) of the treatment effect at all study visits (Month 1, 3, 6 and 12) following Treatment 2 compared to baseline.
Time frame: 1 Month, 3 Months, 6 Months, 12 Months
Quality of Life as measured by PDQ-39 (unilateral)
Between-group comparison (Active Group 1 vs Control Group 1) of the treatment effect at Month 3 following Treatment 1 (unilateral) and within-group comparison (Active Group 1) of the treatment effect at all study visits (Month 1, 3 and 6) following Treatment 1 compared to baseline. Between-group comparison (Active Group 2 vs Control Group 2) of the treatment effect at Month 3 following Treatment 2 (staged bilateral) and within-group comparison (Active Group 2) of the treatment effect at all study visits (Month 1, 3, 6 and 12) following Treatment 2 compared to baseline.
Time frame: 1 Month, 3 Months, 6 Months, 12 Months
Levodopa equivalent dose change usage (milligrams) (unilateral)
Between-group comparison (Active Group 1 vs Control Group 1) of the treatment effect at Month 3 following Treatment 1 (unilateral) and within-group comparison (Active Group 1) of the treatment effect at all study visits (Month 1, 3 and 6) following Treatment 1 compared to baseline. Between-group comparison (Active Group 2 vs Control Group 2) of the treatment effect at Month 3 following Treatment 2 (staged bilateral) and within-group comparison (Active Group 2) of the treatment effect at all study visits (Month 1, 3, 6 and 12) following Treatment 2 compared to baseline.
Time frame: 1 Month, 3 Months, 6 Months, 12 Months
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Nov 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.