A Study In Patients With Neuropathic Pain From Post-Herpetic Neuralgia (PHN)

XenoPort

Status and phase: Completed; Phase 2

Conditions: Neuralgia, Postherpetic

Treatments: Drug: Placebo; Drug: GEn 1200mg/day; Drug: GEn 3600mg/day; Drug: GEn 2400mg/day

Study type: Interventional

Funder types: Industry

Identifiers

NCT00619476

110748

Details and patient eligibility

About

The purpose of this study is to determine whether gabapentin enacarbil (XP13512/GSK1838262), hereafter referred to as GEn is effective in the treatment of neuropathic pain associated with post-herpetic neuralgia (PHN).

Full description

The primary purpose of study PXN110748 was to evaluate efficacy and safety of 3 fixed doses of GEn in the treatment of PHN.

Enrollment: 376 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• 18 years or older
• Female subjects are eligible if of non-childbearing potential or not lactating, has a negative pregnancy, and agrees to use one a specified highly effective method for avoiding pregnancy
• Documented medical diagnosis of PHN of with pain present for at least three months from the healing of a herpes zoster rash
• Baseline 24-hour average pain intensity score ≥ 4.0 based on an 11-point PI-NRS
• Provides written informed consent in accordance with all applicable regulatory requirements

Exclusion criteria

• Other chronic pain conditions not associated with PHN. However, the subject will not be excluded if:
• The pain is located at a different region of the body; and
• The pain intensity is not greater than the pain intensity of the PHN; and
• The subject can assess PHN pain independently of other pain
• Is unable to discontinue prohibited medications or non-drug therapies or procedures throughout the duration of the study
• Hepatic impairment defined as ALT or AST > 2x upper limit of normal (ULN), or alkaline phosphatase or bilirubin > 1.5x ULN
• Chronic hepatitis B or C
• Impaired renal function defined as creatinine clearance <60 mL/min or requiring hemodialysis
• Corrected QT (QTc) interval ≥ 450 msec or QTc interval ≥480 msec for patients with Bundle Branch Block
• Uncontrolled hypertension at screen (sitting systolic >160 mmHg and/or sitting diastolic >90 mmHg)
• Current diagnosis of active epilepsy or any active seizure disorder requiring chronic therapy with antiepileptic drugs
• Medical condition or disorder that would interfere with the action, absorption, distribution, metabolism, or excretion of GEn, or, in the investigator's judgment
• Is considered to be clinically significant and may pose a safety concern, or,
• Could interfere with the accurate assessment of safety or efficacy, or,
• Could potentially affect a subject's safety or study outcome
• Meets criteria defined by the DSM-IV-TR for a major depressive episode or for active significant psychiatric disorders within last year
• Depression in remission, with or without antidepressant treatment, may participate, unless stable antidepressant regimen is a prohibited medication
• Antidepressant medication may not be changed or discontinued to meet entry criteria and must be stable for at least three months prior to enrollment
• History of clinically significant drug or alcohol abuse (DSM-IV-TR) or is unable to refrain from substance abuse throughout the study. Benzodiazepines or atypical benzodiazepines as hypnotic sleep agents permitted.
• Currently participating in another clinical study in which the subject is, or will be exposed to an investigational or non-investigational drug or device
• Has participated in a clinical study and was exposed to investigational or non-investigational drug or device:
• Within preceding month for studies unrelated to PHN, or
• Within preceding six months for studies related to PHN
• Treated previously with GEn
• History of allergic or medically significant adverse reaction to investigational products (including gabapentin) or their excipients, acetaminophen or related compounds

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Triple Blind

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376 participants in 4 patient groups, including a placebo group

Placebo

Placebo Comparator group

Description:

placebo

Treatment:

Drug: Placebo

GEn 1200mg/day

Experimental group

Description:

gabapentin enacarbil 1200mg/day, maintenance treatment 14 weeks

Treatment:

Drug: GEn 1200mg/day

GEn 2400mg/day

Experimental group

Description:

gabapentin enacarbil 2400mg/day, maintenance treatment 14 weeks

Treatment:

Drug: GEn 2400mg/day

GEn 3600mg/day

Experimental group

Description:

gabapentin enacarbil 3600mg/day, maintenance treatment 14 weeks

Treatment:

Drug: GEn 3600mg/day