Please select the eligibility criteria that correspond to the clinical trial below.
Title: Study PXN110527: The Investigation of the Efficacy and Pharmacokinetics of XP13512 in Subjects With Neuropathic Pain Associated With Post-herpetic Neuralgia (PHN) Who Have Had an Inadequate Response to Gabapentin Treatment.
Brief 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.


Options:
A: DISEASE CHARACTERISTICS:

* Has received or is currently receiving neurotoxic chemotherapy, including taxanes (e.g., paclitaxel or docetaxel), platinum-based compounds (e.g., carboplatin, cisplatin, or oxaliplatin), or vinca alkaloids (e.g., vincristine or vinblastine)
* Pain or symptoms of peripheral neuropathy of at least 1 month duration attributed to chemotherapy-induced peripheral neuropathy

  * Average daily pain rating of at least 4 out of 10 using the pain numerical rating scale (where 0 is no pain and 10 is the worst pain possible) OR
  * Evidence of peripheral neuropathy of at least grade 1 out of 3 by ECOG Common

    * Toxicity Criteria for sensory neuropathy
* No other identified causes of painful paresthesia existing prior to chemotherapy

  * No radiotherapy-induced or malignant plexopathy
  * No lumbar or cervical radiculopathy
  * No pre-existing peripheral neuropathy of another etiology, including:

    * B12 deficiency
    * AIDS
    * Monoclonal gammopathy
    * Diabetes
    * Heavy metal poisoning
    * Amyloidosis
    * Syphilis
    * Hyperthyroidism or hypothyroidism
    * Inherited neuropathy

PATIENT CHARACTERISTICS:

Age:

* 18 and over

Life expectancy:

* At least 6 months

Renal:

* Creatinine no greater than 1.5 times upper limit of normal

Other:

* No prior allergic reaction or intolerance to gabapentin
* No significant psychiatric illness (e.g., mania, psychosis, or schizophrenia) that would preclude study compliance
* No extreme difficulty swallowing pills
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception

Other:

* More than 30 days since prior investigational agent for pain control
* Concurrent selective serotonin reuptake inhibitors allowed
* Concurrent nonsteroidal anti-inflammatory drugs allowed
* No concurrent tricyclic antidepressant (e.g., amitriptyline, nortriptyline, or desipramine)\*
* No concurrent monoamine oxidase inhibitor\*
* No concurrent opioid analgesic\*
* No other concurrent adjuvant analgesic (e.g., anticonvulsant, clonazepam, or mexiletine)\*
* No concurrent topical analgesics (e.g., lidocaine gel or lidocaine patch)\*
* No concurrent amifostine
* No concurrent investigational agent for pain control NOTE: \* For pain or symptoms due to chemotherapy-induced peripheral neuropathy
B: 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
C: Inclusion criteria:

* 18 years or older
* Female subjects are eligible to enter if of non-childbearing potential or not lactating, has a negative pregnancy test and agrees to use a specified highly effective method for avoiding pregnancy
* Documented medical diagnosis of Type 1 or 2 diabetes including:
* Stable glycemic control for 3 months defined as \<25% change of routine insulin, \<50% change of routine oral anti-diabetic agent dose and HbA1c \< 8%. (HbA1c of 8 to 11% eligible if attempts to improve diabetic control failed)
* DPN defined by:
* Bilateral reduced or absent reflexes at the ankles, or
* Bilateral impaired vibration, pinprick, fine touch or temperature perception in the distal lower extremities And
* Persistent distal burning or dull pain in the feet, or
* Persistent proximal aching pain in the legs, or
* Paroxysmal electric, shooting, stabbing pain, or
* Dysasthesias, or
* Evoked pain And
* history of pain for at least six months and no greater than five years attributed to DPN (refers to duration of pain)
* Baseline 24-hour average daily pain intensity score \>4.0 as measured on an 11 point pain intensity numerical rating scale
* Provides written informed consent in accordance with all applicable regulatory requirements

Exclusion criteria:

* Other chronic pain conditions not associated with DPN. However, the subject will not be excluded if:
* The pain condition is located at a different region of the body, and
* The pain intensity of this condition is not greater than the pain intensity of the DPN, and
* The subject can assess their DPN independently of other pain condition.
* Other causes of neuropathy or lower extremity 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 either 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 drug(s)
* Medical condition or disorder that would interfere with the action, absorption, distribution, metabolism, or excretion of GEn or pregabalin, or, in the investigator's judgment:
* Is considered to be clinically significant and could 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 met entry criteria and must be stable for at least 3 months prior to enrollment
* History of clinically significant drug or alcohol abuse (DSM-IV-TR). 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 DPN, or
* Within six months for studies related to DPN
* Treated previously with GEn
* History of allergic or medically significant adverse reaction to investigational products (including gabapentin or pregabalin) or their excipients, acetaminophen or related compounds
D: Inclusion Criteria:

* Must be resident of the county of San Diego, California
* Ages 21-70 inclusive
* Low back pain (T-6 or below, secondary to degenerative disk or degenerative joint disease) present "on a daily basis" for the previous 6 months or longer, of at least "moderate" intensity determined by Descriptor Differential Scale (DDS) \> 7
* English-speaking, literate, able to understand the study and communicate with the study team
* Presently not a candidate for back surgery (one prior back surgery permitted if it was \> 5 years ago and resulted in complete relief)
* Discontinued muscle relaxants, anticonvulsants, antidepressants, and opioids at least two weeks before screening and agree to discontinue throughout study (can remain on stable dose of NSAIDs)
* If female, not pregnant or lactating; agrees to use reliable contraception throughout the study, and has negative pregnancy test at screening
* Gives informed consent.

Exclusion Criteria:

* A major coexisting medical illness (e.g., diabetes, renal or hepatic disease, chronic obstructive pulmonary disease, cancer, or class III or IV organic heart disease) that might increase risks of gabapentin, or major surgical or non-surgical intervention for any disorder within the past 12 months, since rehabilitation from treatment may confound study outcomes
* Significant coexisting orthopedic or pain problems; sciatica (pain, weakness, or dysesthesia solely in distribution of a lumbar spinal nerve, with or without reflex change) or back pain due to other disorders (e.g., fibromyalgia, vertebral fracture, osteomyelitis, metastatic cancer, rheumatoid arthritis; spinal stenosis)
* Diagnostic and Statistical Manual (DSM)-IV diagnosis of alcohol or other substance abuse or dependence (within the previous 12 months or positive urine toxicology at screening), current major depression or dysthymia; or lifetime bipolar disorder (I or II) (excluded because gabapentin is antidepressive and antimanic); or major anxiety disorder (e.g., panic disorder; or psychosis; or lifetime presence of cognitive impairment disorder (e.g. dementia)
* History of multiple adverse drug reactions or known allergy to gabapentin
* Use of psychotropics (e.g., antidepressants, anxiolytics), which would need to be continued during the study, or other drugs or agents (i.e., herbal preparations) which might interact with the study drug
* Prior treatment with the study drug
* Use of systemic corticosteroids or corticosteroid injections within three months of screening; or concurrent behavioral therapies, chiropractic treatment, or transcutaneous electrical nerve stimulation unit
* Renal impairment (creatinine \> 1.8 mg/dL)
* Hepatic impairment (bilirubin \> 1.5 X upper normal limit, or aspartate aminotransferase (AST) or alanine transaminase (ALT) \> 2 X upper normal limit)
* Hematologic abnormality (hemoglobin \< 9.4 gm/dL; absolute white blood cell (WBC) count \< 3000/mm3, platelets \< 100,000
* Pregnancy
* Immunosuppression
* Use of experimental drugs or participation in other clinical trials

Answer: B