The Efficacy of MK-8291 in Participants With Post-herpetic Neuralgia (PHN) With Allodynia (MK-8291-012)

Phase 1

Completed

Conditions: Postherpetic Neuralgia

Interventions: Drug: MK-8291
Drug: Placebo

Registration Number: NCT02336555

Lead Sponsor: Merck Sharp & Dohme LLC

Brief Summary: This study aims to determine whether MK-8291 is effective in reducing pain in participants with post-herpetic neuralgia (PHN) with allodynia.

The primary hypothesis is that when compared to placebo, treatment with MK-8291 reduces the change from Baseline in participant-reported pain intensity by 1 on an 11-point numeric rating scale.

Detailed Description: Not available

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 35

Inclusion Criteria

non-pregnant female (and/or partner) agrees to use two acceptable methods of birth control throughout the trial until 2 weeks after the last dose of treatment
female is postmenopausal or surgically sterile
has a clinical diagnosis of PHN with allodynia for at least 3 months duration after healing of rash
has a body mass index (BMI) =< 35 kg/m^2, inclusive
is in good health, with exception of PHN
is on a stable dose for at least 30 days prior to screening if taking any of the following: opioids, non-opioids, paracetomol, non-steroidal anti-inflammatory drugs (NSAIDs), aspirin, antidepressants
is a nonsmoker or has not used nicotine or nicotine containing products for at least prior 3 months

Exclusion Criteria

has a non-PHN chronic pain state
has a history of clinically significant and inadequately treated endocrine, gastrointestinal, cardiovascular, hematological, hepatic, immunological, renal, respiratory, genitourinary, or major neurological (including stroke and chronic seizures) abnormalities or diseases
has a history of malignant cancer
has a history or presence of esophagitis
has a history of significant multiple and/or severe allergies (e.g. food, drug, latex), or has had an anaphylactic reaction or significant intolerability to prescription or non-prescription drugs or food
is positive for hepatitis B surface antigen, hepatitis C antibodies, or human immunodeficiency virus (HIV)
had major surgery, donated or lost approximately 500 mL of blood within 4 weeks prior to screening
has participated in another investigational trial within 4 weeks prior to screening
has a history of risk factors for Torsades de Pointes, has hypokalemia or hypomagnesemia
has a history or presence of clinically significant cardiac arrhythmia, taking substances with the target of reducing heart rate and or exercising endurance sports
has had an injection of local anesthetics or steroids in the region affected by PHN, within 35 days prior to randomization
anticipates using prescription and non-prescription drugs or herbal remedies during trial
consumes excessive amounts of alcoholic or caffeinated beverages
uses cannabis, any illicit drugs, or has a history of drug (including alcohol) abuse within 12 months of screening visit

Study & Design

Study Type: INTERVENTIONAL

Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
MK-8291 → Placebo	MK-8291	In Treatment Period 1, participants were orally administered 10 mg MK-8291 once daily on Days 1 and 2, twice daily on Days 3 to 27, and once daily on Day 28 of the period. After Treatment Period 1, participants were to undergo a minimum of a 7-day Washout Period, which was followed by Treatment Period 2. In Treatment Period 2, participants were orally administered Placebo once daily on Days 1 and 2, twice daily on Days 3 to 27, and once daily on Day 28 of the period. (Total duration of treatment: up to approximately 63 days)
MK-8291 → Placebo	Placebo	In Treatment Period 1, participants were orally administered 10 mg MK-8291 once daily on Days 1 and 2, twice daily on Days 3 to 27, and once daily on Day 28 of the period. After Treatment Period 1, participants were to undergo a minimum of a 7-day Washout Period, which was followed by Treatment Period 2. In Treatment Period 2, participants were orally administered Placebo once daily on Days 1 and 2, twice daily on Days 3 to 27, and once daily on Day 28 of the period. (Total duration of treatment: up to approximately 63 days)
Placebo → MK-8291	Placebo	In Treatment Period 1, participants were orally administered Placebo once daily on Days 1 and 2, twice daily on Days 3 to 27, and once daily on Day 28 of the period. After Treatment Period 1, participants were to undergo a minimum of a 7-day Washout Period, which was followed by Treatment Period 2. In Treatment Period 2, participants were orally administered 10 mg MK-8291 once daily on Days 1 and 2, twice daily on Days 3 to 27, and once daily on Day 28 of the period. (Total duration of treatment: up to approximately 63 days)
Placebo → MK-8291	MK-8291	In Treatment Period 1, participants were orally administered Placebo once daily on Days 1 and 2, twice daily on Days 3 to 27, and once daily on Day 28 of the period. After Treatment Period 1, participants were to undergo a minimum of a 7-day Washout Period, which was followed by Treatment Period 2. In Treatment Period 2, participants were orally administered 10 mg MK-8291 once daily on Days 1 and 2, twice daily on Days 3 to 27, and once daily on Day 28 of the period. (Total duration of treatment: up to approximately 63 days)

Primary Outcome Measures

Name	Time	Method
Change From Baseline in Pain Intensity at Week 4 of Each Treatment Period	Baseline and Days 22-28 of each treatment period (Up to approximately 63 days)	Participants completed a pain intensity questionnaire, the Numerical Rating Scale (NRS), in the morning prior to taking study treatment at Baseline (Day 1) in each treatment period, and then daily up to Day 28 in each treatment period. The NRS assesses the intensity of Post-herpetic Neuralgia (PHN) pain during the preceding 24-hour period on an 11-point numeric rating scale (range: 0=no pain to 10=pain as bad as you can imagine). The mean score in pain intensity of Week 4 (Days 22 to 28) minus the mean score at Baseline is presented, with a negative change representing improvement (or reduction) in pain intensity. In comparison to placebo, a reduction (difference in the change from Baseline) of 1 on the 11-point NRS is expected.

Secondary Outcome Measures

Name	Time	Method
Percentage of Participants Achieving a 30 Percent or Greater Change From Baseline to Day 28 in Pain Intensity	Baseline and Day 28 in each treatment period (Up to approximately 63 days)	Participants completed a pain intensity questionnaire, the Numerical Rating Scale (NRS) in the morning before taking study treatment at Baseline (Day 1) in each treatment period, and then daily from Day 1 up to Day 28 in each treatment period. The NRS assesses the intensity of PHN pain during the preceding 24-hour period on an 11-point numeric rating scale (range: 0=no pain to 10=pain as bad as you can imagine). This was a binary outcome denoting whether the participant reported a percent change from Baseline to Week 4 (Days 22 to 28) in the mean pain intensity score greater than 30%. The percentage of participants who reported a 30% or greater change from Baseline to Day 28 of each treatment period is presented.