Safety and Efficacy of Gabapentin in Diabetic Peripheral Neuropathy

A Multicenter, Randomized, Double-Blind, Placebo-Controlled Study of the Safety and Efficacy of Gabapentin Extended Release (G-ER) Tablets in the Treatment of Patients With Painful Diabetic Peripheral Neuropathy

The purpose of this study is to determine whether a new Gabapentin tablet, is safe and effective for the treatment of painful diabetic peripheral neuropathy.

Study Overview

• Status: Completed
• Conditions: Diabetic Peripheral Neuropathy
• Intervention / Treatment: Drug: Placebo; Drug: Gabapentin Extended Release tablets

• Study Type: Interventional
• Enrollment (Actual): 147
• Phase: Phase 2

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Men or women 18 years or older with diagnosis of type 1 or type 2 diabetes who have reported symmetrical painful symptoms in distal extremities for 1-5 years prior to the study and whose symptoms are attributable to sensorimotor diabetic peripheral neuropathy (DPN).
• Patients of childbearing potential must have a negative urine pregnancy test at screening/randomization, and must use medically acceptable methods of birth control.
• Patient has pain score of at least 4 on the 11-point Likert numerical rating scale at screening. Potential patients should not be informed of the pain intensity eligibility criterion prior to screening or randomization.
• Patient has a mean baseline week pain intensity of at least 4 on the 11-point Likert scale at the end of a one-week pre-treatment period and has completed at least 4 days of diary entries during the baseline week.
• Patient is on stable regimen of antidiabetes medication at screening that can be maintained during the study.
• Patient has hemoglobin A1c (HbA1c) ≤11% at screening.
• Patient has FPG ≤310 mg/dL at screening.
• Patient must have a minimum washout of greater than 5 times the half-life of the drug of any of several medications
• Patients currently treated with gabapentin or pregabalin at screening may be eligible for the study, but must have tapering period wherein the dose of gabapentin is reduced gradually over a period of at least 7 days plus a 2-day or 3-day washout of gabapentin or pregabalin, respectively, prior to start of the Baseline Week.
• Patient must have adequate eyesight to complete questions on the DiaryPro and SitePro. If a patient is unable to do so (for reasons other than severe eye disease) but a caregiver is available to complete these tasks following instruction from the patient, the caregiver may be trained to accomplish these tasks

Exclusion Criteria:

• Patients who have previously not responded to treatment for DPN with gabapentin at doses of ≥1200 mg/day or pregabalin at doses ≥300 mg/day.
• Patients who previously experienced dose-limiting adverse effects that prevented titration of gabapentin to an effective dose.
• Patient has hypersensitivity to gabapentin.
• Patient is a nursing mother.
• Patient has used injected anesthetics or steroids within 30 days of baseline.
• Patient has certain conditions that could confound evaluation of painful DPN, in particular, amputations other than toes, non-diabetic neurologic disorders (e.g. phantom limb pain), and skin conditions affecting sensation in painful limbs.
• Patient has skin conditions in the area affected by the neuropathy that could alter sensation.
• Patient is in an immunocompromised state.
• Patient has an estimated creatinine clearance of <60 ml/min calculated using the Cockroft Gault method (Appendix 3).
• Patient has had malignancy within past 2 years other than basal cell carcinoma.
• Patient has had gastric reduction surgery.
• Patient has severe chronic diarrhea, chronic constipation [unless attributed to drugs that will be washed out], uncontrolled irritable bowel syndrome (IBS) or unexplained weight loss.
• Patient has any abnormal chemistry or hematology results that are deemed by the investigator to be clinically significant.
• Patient has a history of substance abuse within the past year.
• Patient has had 1 or more visits to an emergency room or hospital within the previous 30 days due to hypoglycemia.
• Patient has a history of seizure (except for infantile febrile seizure) or is at risk of seizure due to head trauma.
• Patient has a history of pernicious anemia, untreated hypothyroidism, chronic hepatitis B or C, hepatitis within the past 3 months, or HIV infection.
• Patient has any other serious medical condition that, in the opinion of the Investigator would jeopardize the safety of the patient or affect the validity of the study results.
• Continuing use of any concomitant medication excluded by Inclusion Criterion 8.
• Patient has participated in a clinical trial of an investigational drug or device within 30 days of the screening visit

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 1	Drug: Gabapentin Extended Release tablets
Placebo Comparator: 2	Drug: Placebo

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
The primary study objective is to assess the relative efficacy of G-ER versus placebo in reducing the mean daily pain score from the baseline week to end of efficacy treatment period (Treatment Week 4) in patients with DPN.	4 weeks

Secondary Outcome Measures

Outcome Measure	Time Frame
Secondary efficacy measures will include changes from baseline in average daily sleep interference scores, SF-MPQ, BPI,NPS, PGIC, and CGIC.	4 weeks

Collaborators and Investigators

• Sponsor: Depomed
• Investigators: Study Director: Rekha Sathyanarayana, Depomed

Publications and helpful links

General Publications

• Sandercock D, Cramer M, Biton V, Cowles VE. A gastroretentive gabapentin formulation for the treatment of painful diabetic peripheral neuropathy: efficacy and tolerability in a double-blind, randomized, controlled clinical trial. Diabetes Res Clin Pract. 2012 Sep;97(3):438-45. doi: 10.1016/j.diabres.2012.03.010. Epub 2012 Apr 11.
• Sandercock D, Cramer M, Wu J, Chiang YK, Biton V, Heritier M. Gabapentin extended release for the treatment of painful diabetic peripheral neuropathy: efficacy and tolerability in a double-blind, randomized, controlled clinical trial. Diabetes Care. 2009 Feb;32(2):e20. doi: 10.2337/dc08-1450. No abstract available.

Study record dates

Study Major Dates

• Study Start: April 1, 2006
• Primary Completion (Actual): November 1, 2006
• Study Completion (Actual): December 1, 2006

Study Registration Dates

• First Submitted: July 8, 2008
• First Submitted That Met QC Criteria: July 9, 2008
• First Posted (Estimate): July 10, 2008

Study Record Updates

• Last Update Posted (Estimate): June 8, 2011
• Last Update Submitted That Met QC Criteria: June 6, 2011
• Last Verified: June 1, 2011

More Information

Terms related to this study

• Keywords: Diabetic; Neuropathy; Peripheral; DPN,; Painful
• Additional Relevant MeSH Terms: Nervous System Diseases; Endocrine System Diseases; Diabetes Complications; Diabetes Mellitus; Neuromuscular Diseases; Peripheral Nervous System Diseases; Diabetic Neuropathies; Physiological Effects of Drugs; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Central Nervous System Depressants; Peripheral Nervous System Agents; Analgesics; Sensory System Agents; Excitatory Amino Acid Antagonists; Excitatory Amino Acid Agents; Tranquilizing Agents; Psychotropic Drugs; Anti-Anxiety Agents; Anticonvulsants; Antimanic Agents; Gabapentin
• Other Study ID Numbers: 81-0046

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No