Safety and Efficacy of Gabapentin in Postherpetic Neuralgia

• ClinicalTrials.gov Identifier: NCT00636636
• Recruitment Status: Completed
• First Posted: March 14, 2008
• Results First Posted: January 13, 2012
• Last Update Posted: February 22, 2012
• Sponsor: Depomed
• Information provided by (Responsible Party): Depomed

Study Description

Brief Summary:

Gabapentin and pregabalin are treatments for some types of neuropathic pain, including postherpetic neuralgia (PHN). However, these treatments usually need to be taken 3 times a day for effective pain control. The purpose of this study is to determine whether a new gabapentin tablet, which only needs to be taken once a day, is safe and effective for the treatment of postherpetic neuralgia.

Condition or disease	Intervention/treatment	Phase
Neuralgia,Postherpetic	Drug: Gabapentin Extended Release tablets; Drug: Placebo	Phase 3

Detailed Description:

The primary study objective is to assess the relative efficacy of G-ER dosed once daily (1800 mg following the evening meal), versus placebo in reducing the mean daily pain score from the baseline week to the end of the efficacy treatment period (Treatment Week 10) in patients with PHN.

Secondary efficacy measures will include changes from baseline in mean weekly sleep interference scores, Short-Form McGill Pain Questionnaire (SF-MPQ), the Neuropathic Pain Scale (NPS), Brief Pain Inventory (BPI), Patient Global Impression of Change (PGIC), and Investigator-Rated Clinical Global Impression of Change (CGIC).

Study Design

• Study Type: Interventional (Clinical Trial)
• Actual Enrollment: 452 participants
• Allocation: Randomized
• Intervention Model: Parallel Assignment
• Masking: Double (Participant, Investigator)
• Primary Purpose: Treatment
• Official Title: A Phase 3 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 Postherpetic Neuralgia
• Study Start Date: March 2008
• Actual Primary Completion Date: August 2009
• Actual Study Completion Date: September 2009

Arms and Interventions

Arm	Intervention/treatment
Experimental: G-ER; Gabapentin - Extended Release	Drug: Gabapentin Extended Release tablets; Once-Daily; 300 mg and 600 mg tablets
Placebo Comparator: Placebo; Sugar pill	Drug: Placebo; Once daily; 300 mg and 600 mg tablets

Outcome Measures

Primary Outcome Measures :

1. Mean Change in Baseline Observation Carried Forward (BOCF) Average Daily Pain Score [ Time Frame: 10 weeks ]
   Average daily pain scored on 11-point numerical rating scale (where 0 = no pain, 10 = worst possible pain). Results presented as least squares (LS) mean change in baseline observation carried forward (BOCF) average daily pain score from baseline to the final week of efficacy treatment period (Week 10).

Secondary Outcome Measures :

1. Patient Global Impression of Change (PGIC) [ Time Frame: 10 weeks ]
   Patient self-assessment of how much pain had changed at end of treatment period (Week 10) compared to pain at baseline; scored on 7-point numerical rating scale (where 1 = very much improved, 7 = very much worse). Results presented as number of participants categorized at end of treatment (Week 10) as "very much improved" (score = 1) or "much improved" (score = 2).
2. Clinical Global Impression of Change (CGIC) [ Time Frame: 10 weeks ]
   Investigator assessment of patient's overall PHN symptoms at end of treatment period (Week 10) compared to overall PHN symptoms at baseline; scored on 7-point numerical rating scale (where 1 = very much improved, 7 = very much worse). Results presented as number of participants categorized at end of treatment (Week 10) as "very much improved" (score = 1) or "much improved" (score = 2).
3. Average Daily Sleep Interference Score [ Time Frame: 10 weeks ]
   Assessed on 11-point numeric rating scale (where 0 = pain does not interfere with sleep, 10 = pain completely interferes with sleep); evaluated from daily sleep entry in electronic diary. Results presented as least squares (LS) mean change in baseline observation carried forward (BOCF) average daily sleep interference score from baseline to final week of treatment period (Week 10).

Other Outcome Measures:

1. Mean Change in Last Observation Carried Forward (LOCF) Average Daily Pain Score [ Time Frame: 10 weeks ]
   Average daily pain scored on 11-point numerical rating scale (where 0 = no pain, 10 = worst possible pain). Results presented as least squares (LS) mean change in last observation carried forward (LOCF) average daily pain score from baseline to final week of efficacy treatment period (Week 10).

Eligibility Criteria

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

Criteria

Inclusion Criteria:

1. Men or women 18 years or older who have experienced pain for at least 6 months, but not more than 5 years after the healing of a herpes zoster skin rash(typically about 4 months after the rash first appears).
2. Patient has a pain intensity score of at least 4 on the 11-point Numerical Rating Scale (NRS). Patients should never be informed of the pain intensity criterion prior to screening or randomization.
3. Patients of child-bearing potential must have a negative serum pregnancy test at screening and a negative follow-up urine pregnancy test at randomization.
4. Patient has a mean baseline week pain intensity score of at least 4 on the 11-point NRS scale at the end of a 1-week baseline period and has completed at least 4 days of daily pain diary entries during the baseline week.
5. Patients must have a minimum washout period of greater than 5 times the half-life of the drug of several medications.
6. Patients currently treated with gabapentin pr pregabalin at screening may be eligible for the study, but must have a tapering period wherein the dose of gabapentin or pregabalin is reduced gradually over a period of 5 days followed by a two day washout prior to the Baseline Week.

Exclusion Criteria:

1. Patients who have previously not responded to treatment for PHN with gabapentin or pregabalin.
2. Patients who previously experienced dose-limiting adverse effects that prevented titration of gabapentin to an effective dose.
3. Patient is a nursing mother.
4. Patient has hypersensitivity to gabapentin.
5. Patient has had neurolytic or neurosurgical treatment for PHN.
6. Patient has severe pain from causes other than PHN.
7. Patient has used injected anesthetics or steroids within 30 days of baseline.
8. Patient has skin conditions in the area affected by the neuropathy that could alter sensation.
9. Patient is in an immunocompromised state.
10. Patient has an estimated creatinine clearance less than 50 ml/min.
11. Patient has had malignancy within past 2 years other than basal cell carcinoma.
12. Patient has had gastric reduction surgery.
13. 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.
14. Patient has any abnormal chemistry or hematology results that are deemed by the investigator to be clinically significant.
15. Patient has a history of substance abuse within the past year.
16. Patient has a history of seizure (except for infantile febrile seizure) or is at risk of seizure due to head trauma.
17. Patient has a history of chronic hepatitis B or C, hepatitis within the past 3 months, or HIV infection.
18. Patient has any other clinically significant medical or psychological condition that, in the opinion of the Investigator would jeopardize the safety of the patient or affect the validity of the study results.
19. Continuing use of any concomitant medication excluded by Inclusion Criterion 5.
20. Patient has participated in a clinical trial of an investigational drug or device within 30 days of the screening visit.

Contacts and Locations

Locations

United States, Alabama

Birmingham, Alabama, United States

Tuscaloosa, Alabama, United States

United States, Arizona

Phoenix, Arizona, United States

United States, Arkansas

Little Rock, Arkansas, United States

United States, California

Lancaster, California, United States

Los Angeles, California, United States

Pismo Beach, California, United States

United States, Colorado

Colorado Springs, Colorado, United States

Pueblo, Colorado, United States

United States, Florida

Daytona Beach, Florida, United States

Naples, Florida, United States

New Port Richey, Florida, United States

Orlando, Florida, United States

Tampa, Florida, United States

United States, Georgia

Marietta, Georgia, United States

United States, Hawaii

Honolulu, Hawaii, United States

United States, Illinois

Elk Grove Village, Illinois, United States

United States, Louisiana

Shreveport, Louisiana, United States

United States, Massachusetts

West Yarmouth, Massachusetts, United States

United States, Michigan

Ann Arbor, Michigan, United States

United States, Missouri

Florissant, Missouri, United States

Jefferson City, Missouri, United States

United States, New Mexico

Albuquerque, New Mexico, United States

United States, North Carolina

High Point, North Carolina, United States

United States, North Dakota

Bismarck, North Dakota, United States

Fargo, North Dakota, United States

United States, Ohio

Canton, Ohio, United States

Cincinnati, Ohio, United States

Kettering, Ohio, United States

United States, Rhode Island

Warwick, Rhode Island, United States

United States, South Carolina

Murrells Inlet, South Carolina, United States

Pelzer, South Carolina, United States

United States, Tennessee

Tullahoma, Tennessee, United States

United States, Texas

Austin, Texas, United States

Longview, Texas, United States

United States, Washington

Spokane, Washington, United States

Argentina

Buenos Aires, Argentina

Russian Federation

All over Russia, Russian Federation

St. Petersburg, Russian Federation

Sponsors and Collaborators

Depomed

More Information

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):

Mehta N, Bucior I, Bujanover S, Shah R, Gulati A. Relationship between pain relief, reduction in pain-associated sleep interference, and overall impression of improvement in patients with postherpetic neuralgia treated with extended-release gabapentin. Health Qual Life Outcomes. 2016 Apr 1;14:54. doi: 10.1186/s12955-016-0456-0.

• Responsible Party: Depomed
• ClinicalTrials.gov Identifier: NCT00636636
• Obsolete Identifiers: NCT01465321
• Other Study ID Numbers: 81-0062
• First Posted: March 14, 2008
• Results First Posted: January 13, 2012
• Last Update Posted: February 22, 2012
• Last Verified: February 2012

Keywords provided by Depomed:

Postherpetic Neuralgia (PHN), shingles

Additional relevant MeSH terms:

Neuralgia; Neuralgia, Postherpetic; Peripheral Nervous System Diseases; Neuromuscular Diseases; Nervous System Diseases; Pain; Neurologic Manifestations; Gabapentin; Analgesics; Sensory System Agents; Peripheral Nervous System Agents; Physiological Effects of Drugs; Anticonvulsants; Anti-Anxiety Agents; Tranquilizing Agents; Central Nervous System Depressants; Psychotropic Drugs; Excitatory Amino Acid Antagonists; Excitatory Amino Acid Agents; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Antimanic Agents