A Clinical Trial of PRAX-944 in Participants With Essential Tremor

A Phase 2 Clinical Trial Evaluating the Efficacy, Safety, Tolerability, and Pharmacokinetics of PRAX-944 in Adults With Essential Tremor

This is a 2-part clinical trial to evaluate the efficacy, safety, and tolerability of 40 and 120 mg oral PRAX-944 compared to placebo in the treatment of adults with essential tremor. Part A is designed to study the dose titration from 20 to 40 mg every morning (QAM) (ie, 2 weeks with 7 days at each dose level). Part B is designed to study the dose titration from 20 to up to 120 mg QAM with at least 14 days of dosing at the highest tolerated dose for each participant. Blood levels of PRAX-944 will also be measured throughout the trial and pharmacokinetics will be evaluated.

Study Overview

• Status: Completed
• Conditions: Essential Tremor
• Intervention / Treatment: Drug: Part A: 20 and 40 mg PRAX-944; Drug: Part B: 120 mg PRAX-944; Drug: Part B: 120 mg PRAX-944 and Placebo

• Study Type: Interventional
• Enrollment (Actual): 24
• Phase: Phase 2

Contacts and Locations

Study Locations

• Australia
  • New South Whales
    • New Lambton Heights, New South Whales, Australia, 2305
      • Praxis Research Site
  • Queensland
    • Southport, Queensland, Australia, 4215
      • Praxis Research Site
  • Victoria
    • Fitzroy, Victoria, Australia, 3065
      • Praxis Research Site
    • Melbourne, Victoria, Australia, 3004
      • Praxis Research Site
    • Parkville, Victoria, Australia, 3050
      • Praxis Research Site
• New Zealand
  • Christchurch, New Zealand, 8011
    • Praxis Research Site
  • Auckland
    • Grafton, Auckland, New Zealand, 1023
      • Praxis Research Site
• United States
  • Florida
    • Port Charlotte, Florida, United States, 33980
      • Praxis Research Site
  • Washington
    • Spokane, Washington, United States, 99202
      • Praxis Research Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Clinical diagnosis of ET consistent with Movement Disorders Society Criteria, a duration of ET of at least 3 years and with onset before the age of 65
2. TETRAS upper limb score (ie, sum of bilateral upper limb items 4a, 4b, and 4c) of ≥10 as rated by the Investigator at Screening and Baseline OR A score of ≥2 on 2 or more of the following TETRAS activities of daily living (ADL) subscale items: (2) Feeding with a spoon, (3) Drinking from a glass, (5) Dressing, (6) Pouring, (9) Writing OR A score of ≥2 on 1 of the following TETRAS ADL subscale items: (2) Feeding with a spoon, (3) Drinking from a glass, (5) Dressing, (6) Pouring, or (9) Writing AND a score of ≥2 on both of the following TETRAS ADL subscale items: (10) Working and (12) Social Impact
3. If currently receiving any medication for ET, is on a stable dose of any of these medications for ET for 28 days prior to Screening and is willing to maintain stable doses throughout the trial. If receiving primidone for ET, is willing and able to discontinue 14 days prior to Day 1.
4. Body mass index (BMI) between 18 and 40 kg/m2 (inclusive).

Exclusion Criteria:

1. Sporadically using a benzodiazepine, sleep medication, or anxiolytic that would confound the assessment of tremor.
2. Trauma to the nervous system within 3 months preceding the onset of tremor.
3. History of other medical, neurological or psychiatric condition that may explain or cause tremor, including but not limited to Parkinson's disease, dystonia, cerebellar disease, family history of Fragile X syndrome, traumatic brain injury, alcohol abuse or withdrawal, benzodiazepine abuse or withdrawal, multiple sclerosis, polyneuropathy, and endocrine states such as hyperthyroidism.
4. Prior magnetic resonance-guided focused ultrasound or surgical intervention for ET such as deep brain stimulation or thalamotomy.
5. Botulinum toxin injection for ET in the 6 months prior to Screening.
6. Unwilling or unable to refrain from alcohol 24 hours before and during clinical trial visits.
7. History of substance use disorder

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Part A: Open-label 20 and 40 mg PRAX-944; Once daily, oral dosing with 7 days of 20 mg and 7 days of 40 mg	Drug: Part A: 20 and 40 mg PRAX-944; Once daily oral treatment
Experimental: Part B: Open-label titration PRAX-944 (120 mg) followed by blinded PRAX-944; Once daily, oral dosing with titration to 120 mg: 3 days of 20 mg, 4 days of 40 mg, 7 days of 60 mg, 7 days of 80 mg, 7 days of 100 mg, 28 days of 120 mg	Drug: Part B: 120 mg PRAX-944; Once daily oral treatment with titration
Active Comparator: Part B: Open-label titration PRAX-944 (120 mg) followed by blinded placebo; Once daily, oral dosing with titration to 120 mg: 3 days of 20 mg, 4 days of 40 mg, 7 days of 60 mg, 7 days of 80 mg, 7 days of 100 mg, 14 days of 120 mg, 14 days placebo	Drug: Part B: 120 mg PRAX-944 and Placebo; Once daily oral treatment with titration followed by placebo

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Part A: Change From Baseline in Essential Tremor Rating Assessment Scale (TETRAS) Upper Limb Score	The TETRAS upper limb score is calculated as the sum of the 6 separate upper-limb maneuvers assessed by the clinician: forward-outstretched postural tremor [right], forward outstretched postural tremor [left], lateral wing-beating postural tremor [right], lateral wing-beating postural tremor [left], kinetic tremor [right], kinetic tremor [left], each on a 0 (no tremor) to 4 (maximum tremor) severity scale in 0.5-point increments. TETRAS Part 4 score for both upper limbs ranged from 0 to 24, higher scores indicated more severe tremor. A negative change from baseline indicated less tremor. Baseline is defined as the last non-missing value collected prior to receiving first dose of study drug. Change from baseline will be defined as assessment value minus baseline value.	Baseline (Day 0), Days 7 and 14
Part B: Number of Participants With Adverse Events (AE), Related AE, and AE Leading to Treatment Discontinuation	An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of a study intervention, whether or not considered related to the study intervention. Incidence and Severity of Adverse Events have been reported.	Up to Day 70
Part B: Number of Participants With Clinically Significant Abnormalities in Vital Signs, Laboratory Values and Electrocardiogram Parameters	Vital signs parameters included body temperature, pulse rate, respiratory rate, blood pressure (systolic and diastolic), clinical laboratory measures (chemistry, hematology, urinalysis, and coagulation), electrocardiogram parameters (heart rate, PR, QRS, QT, and corrected QT intervals). Any change in vital sign abnormalities that was clinically significant in the medical and scientific judgment of the investigator and not related to an underlying disease was reported as an unsolicited adverse event (AE). Any clinically significant abnormality associated with underlying disease does not require reporting as an (S)AE unless judged by the investigator to be more severe than expected for the participant's condition.	Up to Day 70
Part B: Number of Participants With Suicidal Ideation or Behavior Assessed Using Columbia Suicide Severity Rating Scale (C-SSRS)	The C-SSRS is described as a scale developed at Columbia University that has 2-6 questions each in categories of Suicidal Ideation, Intensity of Ideation, Suicidal Behavior, and Actual Attempts. Four constructs were measured. Severity of Suicidal ideation is rated on a 5-point ordinal scale. Intensity of ideation is comprised of 5 items (frequency, duration, controllability, deterrents, and reason for ideation), each rated on a 5-point ordinal scale. Suicidal behavior is rated on a nominal scale that includes actual, aborted, and interrupted attempts; preparatory behavior; and non-suicidal self-injurious behavior. Lethality, assesses actual attempts; actual lethality is rated on a 6-point ordinal scale, and if actual lethality is 0, potential lethality of attempts is rated on a 3-point ordinal scale.The higher the C-SSRS score, the higher the suicide risk (ie. worse outcome).	Up to Day 70

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Part A: Change From Baseline in Essential Tremor Rating Assessment Scale (TETRAS) Performance Subscale	The TETRAS is an essential tremor and activities of daily living rating scale. The full scale has 2 sections, the Performance subscale (PS) and the ADL subscale. The PS consists of 9 items covering different body regions. These 9 items are rated on a 5-point scale (ranging from 0 to 4). One item, Item 4, consists of ratings for 3 tasks rated separately for upper limbs on both sides of the body for a total of 6 ratings. The total score of the 9 items (14 ratings) ranges from 0 to 70 with higher scores indicating greater tremor severity. The total score and individual item ratings will be evaluated as outcomes in this trial. Baseline is defined as the last non-missing value collected prior to receiving first dose of study drug.	Baseline (Day 0), Days 7 and 14
Part A: Change From Baseline in Essential Tremor Rating Assessment Scale (TETRAS) Upper Limb Score Measured by Accelerometry	Accelerometer was used to evaluate record coordinates and accelerations in the 3D space over time. The 3 maneuvers in the upper limb item will be completed for both arms, first for the right arm and then for the left. Each upper limb sub-item is scored on a scale from 0 to 4 including to 0.1 increments. The accelerometer upper limb total score, ranges from 0 to 24. A decrease in score is indicative of improvement. Baseline is defined as the last non-missing value collected prior to receiving first dose of study drug. Change from baseline will be defined as assessment value minus baseline value.	Baseline (Day 0), Days 7 and 14
Part A: Change From Baseline in Essential Tremor Rating Assessment Scale (TETRAS) Performance Subscale Individual Items # 6 (Spiral Drawing) and Items #7 (Handwriting)	The TETRAS ADL subscale is a 12-item assessment of typical daily activities that are impacted by tremor. Activities are assessed in the following functional domains: speaking, feeding, drinking, personal hygiene, dressing, writing, and social activity. The impact to each function is rated on a 5-point Likert scale from 0 to 4. The ADL subscale score is calculated as the sum of all 12 items and ranges from 0 to 48 with higher scores reflecting higher impact. Baseline is defined as the last non-missing value collected prior to receiving first dose of study drug. Change from baseline will be defined as assessment value minus baseline value.	Baseline (Day 0), Days 7 and 14
Part A: Number of Participants With Adverse Events (AE), Related AE, and AE Leading to Treatment Discontinuation	An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of a study intervention, whether or not considered related to the study intervention. Incidence and Severity of Adverse Events have been reported.	Up to Day 21
Part A: Number of Participants With Clinically Significant Abnormalities in Vital Signs, Laboratory Values and Electrocardiogram Parameters	Vital signs parameters included body temperature, pulse rate, respiratory rate, blood pressure (systolic and diastolic), clinical laboratory measures (chemistry, hematology, urinalysis, and coagulation), electrocardiogram parameters (heart rate, PR, QRS, QT, and corrected QT intervals). Any change in vital sign abnormalities that was clinically significant in the medical and scientific judgment of the investigator and not related to an underlying disease was reported as an unsolicited adverse event (AE). Any clinically significant abnormality associated with underlying disease does not require reporting as an (S)AE unless judged by the investigator to be more severe than expected for the participant's condition.	Up to Day 21
Part A: Number of Participants With Suicidal Ideation or Behavior Assessed Using Columbia Suicide Severity Rating Scale (C-SSRS)	The C-SSRS is described as a scale developed at Columbia University that has 2-6 questions each in categories of Suicidal Ideation, Intensity of Ideation, Suicidal Behavior, and Actual Attempts. Four constructs were measured. Severity of Suicidal ideation is rated on a 5-point ordinal scale. Intensity of ideation is comprised of 5 items (frequency, duration, controllability, deterrents, and reason for ideation), each rated on a 5-point ordinal scale. Suicidal behavior is rated on a nominal scale that includes actual, aborted, and interrupted attempts; preparatory behavior; and non-suicidal self-injurious behavior. Lethality, assesses actual attempts; actual lethality is rated on a 6-point ordinal scale, and if actual lethality is 0, potential lethality of attempts is rated on a 3-point ordinal scale.The higher the C-SSRS score, the higher the suicide risk (ie. worse outcome).	Up to Day 21
Part B: Change From Baseline in Essential Tremor Rating Assessment Scale (TETRAS) Upper Limb Score During OLT Phase	The TETRAS upper limb score is calculated as the sum of the 6 separate upper-limb maneuvers assessed by the clinician: forward-outstretched postural tremor [right], forward outstretched postural tremor [left], lateral wing-beating postural tremor [right], lateral wing-beating postural tremor [left], kinetic tremor [right], kinetic tremor [left], each on a 0 (no tremor) to 4 (maximum tremor) severity scale in 0.5-point increments. TETRAS Part 4 score for both upper limbs ranged from 0 to 24, higher scores indicated more severe tremor. A negative change from baseline indicated less tremor. Baseline is defined as the last non-missing value collected prior to receiving first dose of study drug. Change from baseline will be defined as assessment value minus baseline value.	Baseline (Day 0) and Day 42
Part B: Change From Baseline in Essential Tremor Rating Assessment Scale (TETRAS) Upper Limb Score During OLT Phase	The TETRAS upper limb score is calculated as the sum of the 6 separate upper-limb maneuvers assessed by the clinician: forward-outstretched postural tremor [right], forward outstretched postural tremor [left], lateral wing-beating postural tremor [right], lateral wing-beating postural tremor [left], kinetic tremor [right], kinetic tremor [left], each on a 0 (no tremor) to 4 (maximum tremor) severity scale in 0.5-point increments. TETRAS Part 4 score for both upper limbs ranged from 0 to 24, higher scores indicated more severe tremor. A negative change from baseline indicated less tremor. Baseline is defined as the last non-missing value collected prior to receiving first dose of study drug. Change from baseline will be defined as assessment value minus baseline value.	Baseline (Day 0), Days 7 and 21
Part B: Change From Baseline in Essential Tremor Rating Assessment Scale (TETRAS) Performance Subscale During OLT Phase	TETRAS Performance Subscale was used to assess essential tremor as scored by the independent video raters. The performance subscale consists of 9 items, i.e. item 1 (head), item 2 (face), item 3 (voice), each of the 6 sub-items for item 4 (upper limb), the maximum of the 4 sub-items for item 5 (lower limb), 2 sub-items (right and left side) for item 6 (Archimedes spirals), item 7 (handwriting), 2 sub-items (right and left side) for item 8 (dot approximation), and item 9 (standing) for a total score ranging from 0 to 64 from 16 sub-items. Each item is rated on a scale of 0 to 4, including 0.5 increments. A lower score is indicative of improvement. The total score has been presented. Baseline is defined as the last non-missing value collected prior to receiving first dose of study drug. Change from baseline will be defined as assessment value minus baseline value.	Baseline (Day 0) and Days 7, 21 and 42
Part B: Change From Baseline in Essential Tremor Rating Assessment Scale (TETRAS) Upper Limb Score Measured by Accelerometry During OLT Phase	Accelerometer was used to evaluate record coordinates and accelerations in the 3D space over time. The 3 maneuvers in the upper limb item will be completed for both arms, first for the right arm and then for the left. Each upper limb sub-item is scored on a scale from 0 to 4 including to 0.1 increments. The accelerometer upper limb total score, ranges from 0 to 24. A decrease in score is indicative of improvement. Baseline is defined as the last non-missing value collected prior to receiving first dose of study drug. Change from baseline will be defined as assessment value minus baseline value.	Baseline (Day 0), and Days 7, 21 and 42
Part B: Change From Baseline in TETRAS Performance Subscale Individual Items # 6 (Spiral Drawing) and Items #7 (Handwriting)	TETRAS Performance Subscale was used to assess essential tremor as scored by the independent video raters. The performance subscale consists of 9 items, i.e. item 1 (head), item 2 (face), item 3 (voice), each of the 6 sub-items for item 4 (upper limb), the maximum of the 4 sub-items for item 5 (lower limb), 2 sub-items (right and left side) for item 6 (Archimedes spirals), item 7 (handwriting), 2 sub-items (right and left side) for item 8 (dot approximation), and item 9 (standing) for a total score ranging from 0 to 64 from 16 sub-items. Each item is rated on a scale of 0 to 4, including 0.5 increments. A lower score is indicative of improvement. Baseline is defined as the last non-missing value collected prior to receiving first dose of study drug. Change from baseline will be defined as assessment value minus baseline value.	Baseline (Day 0), Days 7, 21 and 42
Part B: Change From Baseline in TETRAS Activities of Daily Living (ADL) Score	The TETRAS ADL subscale is a 12-item assessment of typical daily activities that are impacted by tremor. Activities are assessed in the following functional domains: speaking, feeding, drinking, personal hygiene, dressing, writing, and social activity. The impact to each function is rated on a 5-point Likert scale from 0 to 4. The ADL subscale score is calculated as the sum of all 12 items and ranges from 0 to 48 with higher scores reflecting higher impact. Baseline is defined as the last non-missing value collected prior to receiving first dose of study drug. Change from baseline will be defined as assessment value minus baseline value.	Baseline (Day 0), Days 7, 21 and 42
Part B: Change From Baseline in Quality of Life in Essential Tremor Questionnaire (QUEST) Total Scores.	Quality of Life in Essential Tremor Questionnaire (QUEST) is a patient-reported ET-specific 30-item, specific quality of life scale. Items contribute to five dimensions. Physical/ADL (9 items ), Psychosocial (9 items), Communication (3 items), Hobbies/Leisure (3 items), and Work/Finances (6 items). The QUEST total and subscale scores are calculated as the sum of all applicable items divided by the number of applicable items times 100. Higher score indicates greater dissatisfaction with that domain of QOL. Maximal score 100: worse quality of life. Minimal Score 0: best quality of life. Baseline is defined as the last non-missing value collected prior to receiving first dose of study drug. Change from baseline will be defined as assessment value minus baseline value.	Baseline (Day 0), Days 7, 21 and 42

Collaborators and Investigators

• Sponsor: Praxis Precision Medicines
• Collaborators: Praxis Precision Medicines Australia Pty Ltd
• Investigators: Study Director: VP, Clinical Development, Praxis Precision Medicines

Study record dates

Study Major Dates

• Study Start (Actual): March 3, 2020
• Primary Completion (Actual): March 24, 2022
• Study Completion (Actual): March 24, 2022

Study Registration Dates

• First Submitted: August 20, 2021
• First Submitted That Met QC Criteria: August 20, 2021
• First Posted (Actual): August 26, 2021

Study Record Updates

• Last Update Posted (Actual): March 1, 2024
• Last Update Submitted That Met QC Criteria: February 5, 2024
• Last Verified: January 1, 2024

More Information

Terms related to this study

• Keywords: Movement Disorder; Benign Essential Tremor; Familial Tremor; Hereditary Essential Tremor; Movement Disorder Agents; Calcium Channels, T-type
• Additional Relevant MeSH Terms: Central Nervous System Diseases; Nervous System Diseases; Neurologic Manifestations; Movement Disorders; Dyskinesias; Tremor; Essential Tremor; Physiological Effects of Drugs; Central Nervous System Depressants; Peripheral Nervous System Agents; Sensory System Agents; Anesthetics; Anesthetics, Local; Pramoxine
• Other Study ID Numbers: PRAX-944-221

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No