An Effectiveness and Safety Study With RWJ-333369 (Carisbamate) for the Study of Postherpetic Neuralgia (PHN).

Phase 2

Completed

Brief Summary: The purpose of this study is to evaluate the safety, effectiveness, and tolerability of 200 mg of RWJ-333369 given twice daily compared with placebo in the treatment of postherpetic neuralgia.

Detailed Description: Postherpetic neuralgia is a distressing syndrome of neuropathic pain that continues for at least 3 months after the resolution of the varicella-zoster rash (shingles), can last up to years later, and for which therapies are often limited by incomplete pain relief and side effects. This is a randomized (study medication is assigned by chance), double-blind (neither the Investigator or the patient know the name of the assigned study medication), placebo-controlled, crossover, parallel-group, multicenter study to determine the effectiveness and safety of 200 mg of RWJ-333369 given twice daily for 4 weeks compared with placebo in patients with Postherpetic Neuralgia (PHN). The study hypothesis is that 200 mg of RWJ-333369 given twice daily for 4 weeks will be more effective than placebo in reducing pain due to PHN, as measured by average daily PHN pain scores. Patients will receive 200 mg of RWJ-333369 or matching placebo tablets, given in equally divided doses twice daily by mouth, with or without food, for 4 weeks in each of the 2 treatment periods.

Recruitment & Eligibility

Inclusion Criteria

Diagnosis of postherpetic neuralgia (PHN) with a history of varicella-zoster rash (shingles), persistent pain for at least 6 months after the healing of the rash
Experienced postherpetic neuralgia pain on a daily basis for the past 3 months
Women must be postmenopausal for at least 2 years, sexually abstinent, or if sexually active, be practicing an effective method of birth control, and have a negative serum pregnancy test at screening.

Exclusion Criteria

History of a poor response to 3 or more medications for postherpetic neuralgia (PHN), with poor response defined as treatment with medications in the following categories of therapy for at least 1 month at therapeutic dosages without at least moderate improvement, as judged by the study doctor: Antiepileptic drugs, antidepressants, serotonin norepinephrine uptake inhibitors (SNRIs), opioid analgesics, or lidocaine patch
currently taking tricyclic antidepressants, Coumadin (warfarin), or continued treatment with an antiepileptic drug for any indication, Note: If taking these medications, to be eligible for the study, they must be tapered and discontinued
past neurolytic treatment (destruction of nerves by the application of chemicals, heat or cold, neurosurgery, intrathecal pumps, or spinal cord stimulators for PHN pain
currently using herbal topical creams or ointments for pain relief within 48 hours, capsaicin within 6 months, or systemic corticosteroids within 3 months of the baseline period
Prior exposure to RWJ-333369 (carisbamate).

Arm && Interventions

Group	Intervention	Description
002	placebo	placebo twice daily for 4 weeks
001	carisbamate	carisbamate 200 mg tablet twice daily for 4 weeks

Primary Outcome Measures

Name	Time	Method
The mean of the last 7 average daily PHN scores of the first treatment period on days when study drug is taken.	4 weeks

Secondary Outcome Measures

Name	Time	Method
The means of the last 7 average daily PHN pain scores with no use of rescue medication, the last 7 current daily PHN pain scores, the last 7 maximum daily PHN pain scores and the last 7 daily sleep interference scores.	4 weeks (2 four-week treatment periods (cross-over design )