A Clinical Study in Subjects With Neuropathic Pain From PHN Who Have Had an Inadequate Response to Gabapentin Treatment
Condition: Neuralgia, Postherpetic
MeSH terms: Neuralgia; Neuralgia, Postherpetic
Intervention: GEn 1200mg/day; GEn 3600mg/day
Intervention description: 1200mg/day gabapentin enacarbil; 3600mg/day gabapentin enacarbil
Intervention MeSH terms: Gabapentin
Phase: Phase 2
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Enrollment: 96.0
Sex: All
Minimum age: 18 Years
Healthy volunteers: No
Keywords: Post-herpetic neuralgia(PHN); Neuropathic pain

Summary:

      The purpose of this study is evaluate the difference between two doses of gabapentin
      enacarbil (XP13512/GSK1838262), hereafter referred to as GEn, on pain associated with
      post-herpetic neuralgia.
    

Eligibility criteria:

        Inclusion Criteria:

          -  18 years or older

          -  Documented medical diagnosis of PHN with pain present for at least 3 months from the
             healing of a herpes zoster rash

          -  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.

          -  Currently on a stable dose of 1800 mg/day of gabapentin for ≥2 weeks with inadequate
             response OR

          -  Not currently treated with gabapentin, but previously treated with ≥1800 mg/day of
             gabapentin for 4 weeks or more with inadequate response.

          -  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

          -  Current or chronic history of liver disease (including acute viral hepatitis), or
             known hepatic or biliary abnormalities (with the exception of Gilbert's syndrome or
             asymptomatic gallstones).

          -  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