Efficacy and Safety of LX9211 in Participants With Postherpetic Neuralgia

Study Overview
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Brief Summary
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Evaluation of the efficacy of LX9211 compared to placebo in reducing pain related to postherpetic neuralgia over an 11 week assessment period.

Official Title
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A Phase 2, Double-blind, Randomized, Placebo-controlled, Parallel-group Study to Evaluate the Efficacy and Safety of LX9211 in the Treatment of Postherpetic Neuralgia (RELIEF-PHN1)

Conditions
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Postherpetic Neuralgia

Intervention / Treatment
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* Drug: Placebo
* Drug: LX9211


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Participant has given written informed consent to participate in the study in accordance with local regulations Adult male and female participants ≥18 years of age at the time of screening PHN pain that is present for ≥3 months after healing of herpes zoster skin rash affecting a single dermatome (Participants with more than 1 involved dermatome may also be included, provided the affected dermatomes are contiguous) Moderate to severe pain as confirmed by average pain score using scores recorded in the pain diary in the 14 days prior to randomization Exclusion Criteria: Presence of other painful conditions that may confound assessment or self-evaluation of PHN History of major depressive episode, active, significant psychiatric disorders History of clinically significant drug or alcohol use disorder PHN affecting the face Use of opioid medications for management of PHN within the 2 months prior to Screening Visit Use of Non-steroidal anti-inflammatory drugs (NSAIDs) for the specific treatment of PHN pain

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo<br>Following a 2-week Single-blind Run-in period, participants will receive a single loading dose of matching-placebo to LX9211 tablet, orally, on Day 1 and maintenance doses, orally, once daily from Day 2 to Week 6. | Drug: Placebo<br>* LX9211 matching-placebo, tablets will be administered orally.<br>|
| Experimental: LX9211<br>Following a 2-week Single-blind Run-in period, participants will receive a single loading dose of 200 milligrams (mg) tablet, orally, on Day 1 and maintenance doses of 20 mg, orally, once daily from Day 2 to Week 6. | Drug: LX9211<br>* LX9211, 200 mg, tablets will be administered orally.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from Baseline in Average Daily Pain Score (ADPS) | The change from Baseline (Week 2) to Week 6 in Average Daily Pain Score (ADPS), based on the 11-point numerical rating scale (0 [No Pain] to 10 [Pain as bad as you can imagine]) | Day 1 to Week 6 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| ≥30 percent reduction in pain intensity | Proportion of patients with ≥30% reduction in pain intensity | Day 1 to Week 6 | 
| ≥50 percent reduction in pain intensity | Proportion of patients with ≥50% reduction in pain intensity | Day 1 to Week 6 | 
| Safety: number of AEs reported | Number of Adverse Events | Day 1 to Week 6 |