Safety and Efficacy Study for the Treatment of Painful Diabetic Neuropathy

Inclusion Criteria

• Age ≥ 18 years to ≤ 75 years
• Documented history of Type I or II diabetes with current treatment control (glycosylated hemoglobin A1c of ≤ 10.0% at Screening) and currently on oral medication and/or insulin
• Diagnosis of painful diabetic peripheral neuropathy in both lower extremities
• Lower extremity pain for at least 6 months
• Visual analog scale (VAS) score of ≥ 40 mm at Initial Screening (0 mm = no pain - 100 mm very severe pain)
• Symptoms from the Brief Pain Neuropathy Screening (BPNS) is ≤ 5 point difference between legs at Initial Screening
• The average daily pain intensity score of the Daily Pain and Sleep Interference Diary completed after medication wash-out is ≥ 4 with a standard deviation ≤ 2
• The physical examination component of the Michigan Neuropathy Screening Instrument Score (MNSI) is ≥ 3 at Screening
• Stable treatment of diabetes for at least 3 months with no anticipated changes in medication regimen, and no new symptoms associated with diabetes
• If female of childbearing potential, negative urine pregnancy test at screening and using acceptable method of birth control during the study

Exclusion Criteria

• Peripheral neuropathy caused by condition other than diabetes
• Other pain more severe than neuropathic pain
• Progressive or degenerative neurological disorder
• Myopathy
• Inflammatory disorder of the blood vessels (inflammatory angiopathy, such as Buerger's disease)
• Active infection
• Chronic inflammatory disease (e.g., Crohn's disease, rheumatoid arthritis)
• Positive HIV or HTLV at Screening
• Active Hepatitis B or C as determined by Hepatitis B core antibody (HBcAB), antibody to Hepatitis B antigen (IgG and IgM; HbsAb), Hepatitis B surface antigen (HBsAg) and Hepatitis C antibodies (Anti-HCV) at Screening
• Subjects with known immunosuppression or currently receiving immunosuppressive drugs, chemotherapy or radiation therapy
• Stroke or myocardial infarction within last 3 months
• Ophthalmologic conditions pertinent to proliferative retinopathy or conditions that preclude standard ophthalmologic examination
• Specific laboratory values at Screening including: Hemoglobin 2.0 mg/dL; AST and/or ALT > 3 times the upper limit of normal or any other clinically significant lab abnormality which in the opinion of the investigator should be exclusionary
• Uncontrolled hypertension as defined as sustained systolic blood pressure (SBP) > 200 mmHg or diastolic BP (DBP) > 110 mmHg at Screening
• Patients with a recent history ( 81 mg daily of acetylsalicylic acid; If ≥ 81 mg are taken at screening, subjects may be enrolled if willing/able to switch to another medication
• Use of any opioids; subjects may be enrolled if willing and able to discontinue use of these drugs 14 days prior to starting the 7 Day Daily Pain and Sleep Interference Diary and refrain from taking these drugs for the duration of the study
• Subjects requiring regular COX-2 inhibitor drug(s) or non-specific COX-1/COX-2 inhibiting drugs, or high dose steroids (excepting inhaled steroids).Subjects may be enrolled if willing/able to undergo medication wash-out prior to the first dosing and to refrain from taking these drugs for the duration of the study;
• Major psychiatric disorder in within last 6 months
• Body mass index (BMI) > 45 kg/m2 at Screening
• Any lower extremity amputation
• Use of an investigational drug or treatment in past 6 months
• Unable or unwilling to give informed consent