Efficacy and Safety Study of Z160 in Subjects With Postherpetic Neuralgia

Study Overview
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Brief Summary
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This study will compare Z160 and placebo in patients with Postherpetic Neuralgia for safety and efficacy for a period of 6 weeks.

Official Title
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A Phase 2, Multicenter, Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study to Evaluate the Efficacy and Safety of Z160 in Subjects With Postherpetic Neuralgia

Conditions
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Postherpetic Neuralgia

Intervention / Treatment
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* Drug: Z160
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Provide written informed consent. Either sex but must be aged >=18 years. Diagnosis of PHN as defined by the presence of pain in the area affected by herpes zoster >=6 months after the herpes zoster skin rash has healed. Pain score over the last week of >=3 and <=8 on the PI-NRS If female, the subject must be postmenopausal , surgically sterilized for >=3 months before the screening visit, or agree to use 2 reliable methods of contraception if of childbearing potential. If male, the subject must agree to use condoms. Willing and able to comply with all study procedures. Exclusion Criteria: Severe pain caused by diseases other than PHN. Neurolytic or neurosurgical therapy for PHN within 6 months of screening (subjects who received a spinal cord stimulator implant at least 6 months before screening are eligible, but the settings need to remain stable during the double blind study period without use of a magnet). History of seizure, excluding pediatric febrile seizures, or currently has seizures. Stroke or transient ischemic attack (TIA) <=6 months before the screening visit. History of or a current diagnosis of schizophrenia or bipolar disorder. Major depressive disorder or generalized anxiety disorder <=6 months before the screening visit. Subjects who are on stable doses of selective serotonin uptake inhibitors (SSRIs) for depression (other than major depressive disorder) are eligible for the study. Clinically significant alcohol or substance dependency <=1 year before the screening visit Imminent risk of suicide (positive response to question 4 or 5 on the C-SSRS) or had a suicide attempt within 6 months before the screening visit. Clinically significant conditions that, in the investigator's opinion, may interfere with the study procedures or compromise the subject's safety. Malignancy (other than nonmetastatic basal or squamous cell carcinoma of the skin or carcinoma in situ of other organs that was surgically removed >1 year before screening and has not recurred). Condition that is known to interfere with the absorption, distribution, metabolism, or excretion of drugs. Illness within 30 days before screening. History of hypersensitivity to calcium channel blockers. Multiple drug allergies Opioids (at doses exceeding the equivalent of 15 mg of oral morphine) or a high-dose capsaicin patch (Qutenza) <=30 days before the screening visit. Moderate or strong cytochrome P450 inducer within 30 days before the screening visit. Digoxin or prohibited medications that cannot be discontinued before randomization. Other exclusions apply.

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 |
| --- | --- |
| Experimental: Z160<br>375 mg BID | Drug: Z160<br> <br> |
| Placebo Comparator: Placebo<br>matching placebo control | Drug: Placebo<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline to Week 6 in the weekly average pain score based on Pain Intensity-Numeric Rating Scale (PI-NRS) |  | Baseline to Week 6 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in weekly average pain score |  | Baseline to Weeks 1, 2, 3, 4, 5, 6 | 
| Neuropathic Pain Scale (NPS) |  | Baseline to Weeks 1, 2, 4, 6 | 
| Patient Global Impression of Change (PGIC) |  | Baseline to Week 6 | 
| Profile of Mood States (POMS) |  | Baseline to Weeks 1, 2, 4, 6 | 
| Daily Sleep Interference Scale (DSIS) |  | Baseline to Weeks 1, 2, 3, 4, 5, 6 | 
| Short Form 36 (SF-36) |  | Baseline to Week 6 | 
| Z160 plasma concentrations |  | Baseline to Weeks 1, 2, 4, 6 | 
| Time to a >= 30% reduction in weekly average pain score |  | Baseline to Weeks 1, 2, 3, 4, 5, 6 | 
| Time to a >= 50% reduction in weekly average pain score |  | Baseline to Weeks 1, 2, 3, 4, 5, 6 | 
| Subjects who have >= 30% reduction in average daily pain score |  | Baseline to Week 6 | 
| Subjects who have >= 50% reduction in average daily pain score |  | Baseline to Week 6 | 
| Safety and tolerability | As measured by the frequency and severity of adverse events, frequency of severe adverse events, and discontinuations due to adverse events | Baseline to Weeks 1- 12 | 
| Amount of rescue medication used |  | Baseline to Weeks 1, 2, 4 and 6 |