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Safety/Efficacy Study of Retigabine vs. Placebo in Post-Herpetic Neuralgia (PHN)

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
Valeant Pharmaceuticals International, Inc.
ClinicalTrials.gov Identifier:
NCT00612105
First received: January 25, 2008
Last updated: December 9, 2011
Last verified: November 2011
Results First Received: July 8, 2011  
Study Type: Interventional
Study Design: Allocation: Randomized;   Endpoint Classification: Safety/Efficacy Study;   Intervention Model: Parallel Assignment;   Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor);   Primary Purpose: Treatment
Condition: Postherpetic Neuralgia
Interventions: Drug: Retigabine
Drug: Placebo

  Participant Flow
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Recruitment Details
Key information relevant to the recruitment process for the overall study, such as dates of the recruitment period and locations
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Pre-Assignment Details
Significant events and approaches for the overall study following participant enrollment, but prior to group assignment
No text entered.

Reporting Groups
  Description
1: Retigabine Arm Description: Participants started on a total daily dose of 150 milligrams (mg) and were titrated to their maximum tolerated dose (MTD) up to a maximum of 900 mg daily using retigabine 50 mg and/or 100 mg tablets. The dose was increased by 150 mg each week and administered 3 times daily (TID) in equally divided doses. In the Maintenance Phase, retigabine was administered in equally divided doses to maintain the participant’s MTD. Participants with moderate to severe side effects during the first week at their MTD and who had attained at least dose level 3 (450 mg) were allowed a one level dose reduction (150 mg). Participants unable to maintain the MTD discontinued the medication. In the Taper Phase, the dose was reduced by one-third during each of the first two weeks, and the study medication was stopped by the third week during the 3-week duration.
2: Placebo Arm Description: Matching placebo tablets of dummy strengths of 50 mg and 100 mg were administered orally TID for up to 6 weeks of the Titration Phase, 4 weeks of the Maintenance Phase, and 3 weeks of the Taper Phase.

Participant Flow for 3 periods

Period 1:   Period Title 1: 6-Week Titration Phase
    1: Retigabine     2: Placebo  
STARTED     125     62  
COMPLETED     89     57  
NOT COMPLETED     36     5  
Adverse Event                 18                 1  
Withdrawal by Subject                 6                 1  
Lost to Follow-up                 2                 0  
Physician Decision                 1                 1  
Protocol Violation                 1                 0  
Missed study drug for more than two days                 3                 1  
Lack of Efficacy                 5                 0  
Unknown                 0                 1  

Period 2:   Period Title 2: 4-Week Maintenance Phase
    1: Retigabine     2: Placebo  
STARTED     89     57  
COMPLETED     78     55  
NOT COMPLETED     11     2  
Adverse Event                 9                 1  
Missed study drug for more than two days                 1                 1  
Lost to Follow-up                 1                 0  

Period 3:   Period Title 3: 3-Week Taper Phase
    1: Retigabine     2: Placebo  
STARTED     86 [1]   58 [1]
COMPLETED     85     58  
NOT COMPLETED     1     0  
Unknown                 1                 0  
[1] Includes participants who discontinued during the titration phase and entered taper phase.



  Baseline Characteristics
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Population Description
Explanation of how the number of participants for analysis was determined. Includes whether analysis was per protocol, intention to treat, or another method. Also provides relevant details such as imputation technique, as appropriate.
No text entered.

Reporting Groups
  Description
1: Retigabine Arm Description: Participants started on a total daily dose of 150 milligrams (mg) and were titrated to their maximum tolerated dose (MTD) up to a maximum of 900 mg daily using retigabine 50 mg and/or 100 mg tablets. The dose was increased by 150 mg each week and administered 3 times daily (TID) in equally divided doses. In the Maintenance Phase, retigabine was administered in equally divided doses to maintain the participant’s MTD. Participants with moderate to severe side effects during the first week at their MTD and who had attained at least dose level 3 (450 mg) were allowed a one level dose reduction (150 mg). Participants unable to maintain the MTD discontinued the medication. In the Taper Phase, the dose was reduced by one-third during each of the first two weeks, and the study medication was stopped by the third week during the 3-week duration.
2: Placebo Arm Description: Matching placebo tablets of dummy strengths of 50 mg and 100 mg were administered orally TID for up to 6 weeks of the Titration Phase, 4 weeks of the Maintenance Phase, and 3 weeks of the Taper Phase.
Total Total of all reporting groups

Baseline Measures
    1: Retigabine     2: Placebo     Total  
Number of Participants  
[units: participants]
  125     62     187  
Age  
[units: participants]
     
<=18 years     0     0     0  
Between 18 and 65 years     64     34     98  
>=65 years     61     28     89  
Age  
[units: years]
Mean ± Standard Deviation
  63.2  ± 11.07     61.2  ± 14.28     62.5  ± 12.23  
Gender  
[units: participants]
     
Female     64     36     100  
Male     61     26     87  
Region of Enrollment  
[units: participants]
     
United States     94     47     141  
South Africa     31     15     46  



  Outcome Measures
  Show All Outcome Measures

1.  Primary:   Primary Endpoint Will be the Change From Baseline in Average Pain Score Over the Last 7 Days of the Maintenance Phase.   [ Time Frame: Baseline and Week 4 (Maintenance Phase-MP) ]

2.  Secondary:   Change From Baseline to Weeks 2 and 4 of the Maintenance Phase in Mean In-clinic Pain Assessment   [ Time Frame: Baseline and Weeks 2 and 4 (Maintenance Phase - MP) ]

3.  Secondary:   Number of Rescue Medication Tablets Taken Per Day During the Maintenance Phase (MP)   [ Time Frame: Weeks 1, 2, 3, and 4 Maintenance Phase ]

4.  Secondary:   Change From Baseline in Pain Intensity Score at Each Week During the Maintenance Phase (MP)   [ Time Frame: Baseline and Weeks 1, 2, 3, and 4 (MP) ]

5.  Secondary:   Number of Participants Classified as Responders, With a 50% and 30% Pain Reduction From Baseline to the Last 7 Days of the Maintenance Phase   [ Time Frame: Baseline and Week 4 Maintenance Phase (MP) ]

6.  Secondary:   Change From Baseline to the End of the MP (Included All Participants Who Completed Week 4 of the MP and Who Terminated Early During the MP) in Medical Outcomes Study (MOS) Sleep Scale Scores   [ Time Frame: Baseline and End of Maintenance Phase (MP) (Week 4). ]

7.  Secondary:   Change From Baseline to the End of the MP (Included All Participants Who Completed Week 4 of the MP and Who Terminated Early During the MP) in Sleep Quantity   [ Time Frame: Baseline and End of Maintenance Phase (MP) (Week 4). ]

8.  Secondary:   Number of Participants With the Indicated Change From Baseline to the End of the Maintenance Phase in Optimal Sleep Based on the Sleep Quantity Domain of the MOS Sleep Scale   [ Time Frame: Baseline and End of Maintenance Phase (MP) (Week 4). ]

9.  Secondary:   Number of Participants With the Indicated Overall Patient Global Impression of Change (PGIC)   [ Time Frame: Baseline to the end of Maintenance Phase (MP) (Week 4) ]

10.  Secondary:   Mean Score on the Treatment Satisfaction Questionnaire for Medication (TSQM) at the End of the Maintenance Phase   [ Time Frame: End of Maintenance Phase (MP) (Week 4) ]

11.  Secondary:   Scores on the Brief Pain Inventory-Short Form (BPI-SF) at the End of the MP for All Participants Who Completed Week-4 of the MP and Who Terminated Early During the MP   [ Time Frame: End of Maintenance Phase (MP) (Week 4) ]

12.  Secondary:   Scores on the Medical Outcomes Short Form-36 (SF-36) at the End of the MP for All Participants Who Completed Week 4 of the MP and Who Terminated Early During the MP   [ Time Frame: End of Maintenance Phase (MP) (Week 4) ]

13.  Secondary:   Scores for Reported Health Transition at the End of the MP for All Participants Who Completed Week 4 of the MP and Who Terminated Early During the MP   [ Time Frame: End of maintenance Phase (MP) (Week 4) ]

14.  Secondary:   Number of Participants With the Indicated Responses at Baseline to the Question: “How Painful Was the Affected Side Compared to the Opposite Side?” in an Assessment of Tactile Allodynia   [ Time Frame: Baseline Phase (Day -7 to Randomization Day 0) ]

15.  Secondary:   Number of Participants With the Indicated Responses at Baseline to the Questions of “Is it Cool?” and “Is it Painful?” in an Assessment of Cold Threshold and Allodynia   [ Time Frame: Timeframe: Baseline Phase (Day -7 to Randomization Day 0) ]

16.  Secondary:   Number of Participants With the Indicated Responses at Baseline to the Questions: “How Sharp Was the Affected Side Compared to the Opposite Side?” and “How Painful Was the Affected Side Compared to the Opposite Side?” in an Assessment of Hyperalgesia   [ Time Frame: Baseline Phase (Day -7 to Randomization Day 0) ]

17.  Secondary:   Number of Participants With the Indicated Responses at the End of the MP to the Question: “How Painful Was the Affected Side Compared to the Opposite Side?” in an Assessment of Tactile Allodynia   [ Time Frame: End of Maintenance Phase (MP) (Week 4) ]

18.  Secondary:   Number of Participants With the Indicated Responses at the End of the MP to the Questions of “Is it Cool?” and “Is it Painful?” in an Assessment of Cold Threshold and Allodynia   [ Time Frame: End of Maintenance Phase (MP) (Week 4) ]

19.  Secondary:   Number of Participants With Indicated Responses at the End of the MP to the Questions: “How Sharp Was the Affected Side Compared to the Opposite Side?” and “How Painful Was the Affected Side Compared to the Opposite Side?” in an Assessment of Hyperalgesia   [ Time Frame: End of Maintenance Phase (MP) (Week 4) ]

20.  Secondary:   Change From Baseline in the Average Diary Pain Score to the Last 7 Days of the Maintenance Phase by Post Herpetic Neuralgia (PHN) Subtype "Irritable Nociceptors"   [ Time Frame: Baseline and Week 4 Maintenance Phase (MP) ]

21.  Secondary:   Change From Baseline in the Average Diary Pain Score to the Last 7 Days of the Maintenance Phase by Post Herpetic Neuralgia (PHN) Subtype"Deafferentation Type 1 (D Type 1)"   [ Time Frame: Baseline and Week 4 Maintenance Phase (MP) ]

22.  Secondary:   Change From Baseline in the Average Diary Pain Score to the Last 7 Days of the Maintenance Phase by Post Herpetic Neuralgia (PHN) Subtype "Deafferentation Type 2 (D Type 2)"   [ Time Frame: Baseline and Week 4 Maintenance phase (MP) ]

23.  Secondary:   Change From Baseline in the Average Diary Pain Score to the Last 7 Days of the Maintenance Phase by Post Herpetic Neuralgia (PHN) Subtype "Unclassifiable"   [ Time Frame: Baseline and Week 4 Maintenance Phase (MP) ]


  Serious Adverse Events


  Other Adverse Events


  Limitations and Caveats
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Limitations of the study, such as early termination leading to small numbers of participants analyzed and technical problems with measurement leading to unreliable or uninterpretable data
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  More Information
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Certain Agreements:  
Principal Investigators are NOT employed by the organization sponsoring the study.
There IS an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.
The agreement is:
unchecked The only disclosure restriction on the PI is that the sponsor can review results communications prior to public release and can embargo communications regarding trial results for a period that is less than or equal to 60 days. The sponsor cannot require changes to the communication and cannot extend the embargo.
unchecked The only disclosure restriction on the PI is that the sponsor can review results communications prior to public release and can embargo communications regarding trial results for a period that is more than 60 days but less than or equal to 180 days. The sponsor cannot require changes to the communication and cannot extend the embargo.


Results Point of Contact:  
Name/Title: Associate Director Clinical Operations
Organization: Valeant Pharmaceuticals International, Inc.
phone: 919-294-3080
e-mail: david.lineberry@valeant.com


No publications provided


Responsible Party: Valeant Pharmaceuticals International, Inc.
ClinicalTrials.gov Identifier: NCT00612105     History of Changes
Other Study ID Numbers: VRX-RET-E22-NP201
Study First Received: January 25, 2008
Results First Received: July 8, 2011
Last Updated: December 9, 2011
Health Authority: United States: Food and Drug Administration