Clinical trial NCT00636636: Safety and Efficacy of Gabapentin in Postherpetic Neuralgia
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 type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE3
Conditions: Neuralgia,Postherpetic
Keywords: Postherpetic Neuralgia (PHN), shingles
Lead sponsor: Depomed
Sponsor class: INDUSTRY
First posted: 2008-03-14
Enrollment: 452
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

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.

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).

Eligibility 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.

Primary outcomes:
measure: Mean Change in Baseline Observation Carried Forward (BOCF) Average Daily Pain Score
timeFrame: 10 weeks
Secondary outcomes:
measure: Patient Global Impression of Change (PGIC)
timeFrame: 10 weeks
measure: Clinical Global Impression of Change (CGIC)
timeFrame: 10 weeks
measure: Average Daily Sleep Interference Score
timeFrame: 10 weeks
Other outcomes:
measure: Mean Change in Last Observation Carried Forward (LOCF) Average Daily Pain Score
timeFrame: 10 weeks
Locations:
city: Birmingham
country: United States
state: Alabama
city: Tuscaloosa
country: United States
state: Alabama
city: Phoenix
country: United States
state: Arizona
city: Little Rock
country: United States
state: Arkansas
city: Lancaster
country: United States
state: California
city: Los Angeles
country: United States
state: California
city: Pismo Beach
country: United States
state: California
city: Colorado Springs
country: United States
state: Colorado
city: Pueblo
country: United States
state: Colorado
city: Daytona Beach
country: United States
state: Florida
city: Naples
country: United States
state: Florida
city: New Port Richey
country: United States
state: Florida
city: Orlando
country: United States
state: Florida
city: Tampa
country: United States
state: Florida
city: Marietta
country: United States
state: Georgia
city: Honolulu
country: United States
state: Hawaii
city: Elk Grove Village
country: United States
state: Illinois
city: Shreveport
country: United States
state: Louisiana
city: West Yarmouth
country: United States
state: Massachusetts
city: Ann Arbor
country: United States
state: Michigan
city: Florissant
country: United States
state: Missouri
city: Jefferson City
country: United States
state: Missouri
city: Albuquerque
country: United States
state: New Mexico
city: High Point
country: United States
state: North Carolina
city: Bismarck
country: United States
state: North Dakota
city: Fargo
country: United States
state: North Dakota
city: Canton
country: United States
state: Ohio
city: Cincinnati
country: United States
state: Ohio
city: Kettering
country: United States
state: Ohio
city: Warwick
country: United States
state: Rhode Island
city: Murrells Inlet
country: United States
state: South Carolina
city: Pelzer
country: United States
state: South Carolina
city: Tullahoma
country: United States
state: Tennessee
city: Austin
country: United States
state: Texas
city: Longview
country: United States
state: Texas
city: Spokane
country: United States
state: Washington
city: Buenos Aires
country: Argentina
city: All over Russia
country: Russian Federation
city: St. Petersburg
country: Russian Federation
Study officials:
References:
citation: 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.