Efficacy and Safety of Arbaclofen Placarbil in Subjects With Spasticity Due to Multiple Sclerosis

This study has been completed.
Information provided by (Responsible Party):
XenoPort, Inc.
ClinicalTrials.gov Identifier:
First received: May 22, 2011
Last updated: February 28, 2013
Last verified: February 2013

To evaluate the efficacy of three doses of XP19986 (arbaclofen placarbil) compared to placebo for the treatment of spasticity in subjects with multiple sclerosis (MS).

Condition Intervention Phase
Multiple Sclerosis
Drug: arbaclofen placarbil
Drug: Placebo
Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: A Randomized, Double Blind, Placebo-Controlled Efficacy and Safety Study of Arbaclofen Placarbil in Subjects With Spasticity Due to Multiple Sclerosis

Resource links provided by NLM:

Further study details as provided by XenoPort, Inc.:

Primary Outcome Measures:
  • Change from Baseline in Maximum Ashworth Scale score (6 hour post-dose time point) [ Time Frame: 10-weeks ] [ Designated as safety issue: No ]
  • Patient Global Impression of Change (PGIC) score [ Time Frame: 10-weeks ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Change in the overall Modified PRISM score [ Time Frame: Weeks 4, 6, 10 ] [ Designated as safety issue: No ]
  • Change in weekly average severity of pain score associated with muscle spasm. [ Time Frame: Week 10 ] [ Designated as safety issue: No ]
  • Change in weekly average VAS score of sleep quality [ Time Frame: Week 10 ] [ Designated as safety issue: No ]

Enrollment: 228
Study Start Date: May 2011
Primary Completion Date: February 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: 15 mg BID Drug: arbaclofen placarbil
arbaclofen placarbil 15 mg BID
Experimental: 30 mg BID Drug: arbaclofen placarbil
arbaclofen placarbil 30 mg BID
Experimental: 45 mg BID Drug: arbaclofen placarbil
arbaclofen placarbil 45 mg BID
Placebo Comparator: Placebo BID Drug: Placebo
Placebo for arbaclofen placarbil 15, 30 and 45 mg BID


Ages Eligible for Study:   18 Years to 70 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  1. Has multiple sclerosis (MS) based on Poser or McDonald Criteria (all subtypes of MS will be accepted, including relapsing remitting, primary or secondary progressive, if disease is stable per exclusion criteria).
  2. Maximum Ashworth Score Scale score of ≥ 2 in at least one of the following muscle groups on either side of the body: hip abductors/adductors, knee flexors/extensors, ankle flexors/extensors.
  3. Expanded Disability Status Scale (EDSS) rating between 3.0-8.0 inclusive.
  4. If a subject is on disease modifying MS treatment, the dosage, frequency, and route of administration must be stable for at least 30 days before screening and is expected to be stable throughout the study.
  5. Spasticity Disability Rating of 2 or higher at Baseline.
  6. Willing to discontinue and refrain from using for the duration of the study drugs for the treatment of spasticity or likely to affect spasticity (including, but not limited to, baclofen, tizanidine, diazepam, clonazepam, metaxalone, dantrolene, cyclobenzaprine, carisoprodol, clonidine, vigabatrin, valproic acid and cannabis).

Exclusion Criteria:

  1. Spasticity due to neurological disorder other than MS or other conditions that may confound the assessment of spasticity.
  2. Subject has clinically evident muscle contractures resulting in irreversible spasticity in lower extremities.
  3. Subjects who have suffered an acute relapse of MS (as determined by the Investigator) within 90 days prior to Screening, or have had more than 1 relapse within the year prior to Screening
  4. Botulinum toxin injection within 6 months of Screening or has current residual associated side effects at Screening.
  5. Subjects receiving concomitant medication from more than one of the following three drug classes: (Antiepileptic drugs, Tricyclic anti-depressants and Opioids)
  6. Subjects on the following medications, at doses above the specified limits, are excluded if they cannot maintain a level within these limits

    • Gabapentin ≤ 1800 mg per day or pregabalin ≤ 150 mg per day
    • Amitriptyline ≤ 75 mg per day or nortriptyline ≤ 75 mg per day
    • Opioids ≤ 30 mg morphine equivalents per day.
  7. Evidence of unstable or severe systemic illness, including but not limited to: Cardiovascular disease (e.g., chronic ventricular arrhythmia, unstable angina or CHF), respiratory disease (e.g., sleep apnea, COPD requiring oxygen therapy or hospitalization in last year), endocrine disease, hepatic disease (e.g., chronic active hepatitis), renal disease, or immunodeficiency.
  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT01359566

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Sponsors and Collaborators
XenoPort, Inc.
  More Information

No publications provided

Responsible Party: XenoPort, Inc.
ClinicalTrials.gov Identifier: NCT01359566     History of Changes
Other Study ID Numbers: XP-B-089
Study First Received: May 22, 2011
Last Updated: February 28, 2013
Health Authority: United States: Food and Drug Administration

Additional relevant MeSH terms:
Multiple Sclerosis
Autoimmune Diseases
Autoimmune Diseases of the Nervous System
Demyelinating Autoimmune Diseases, CNS
Demyelinating Diseases
Immune System Diseases
Nervous System Diseases
Pathologic Processes
Arbaclofen placarbil
Central Nervous System Agents
GABA Agents
GABA Agonists
GABA-B Receptor Agonists
Molecular Mechanisms of Pharmacological Action
Muscle Relaxants, Central
Neuromuscular Agents
Neurotransmitter Agents
Peripheral Nervous System Agents
Pharmacologic Actions
Physiological Effects of Drugs
Therapeutic Uses

ClinicalTrials.gov processed this record on March 25, 2015