<br>        Inclusion Criteria:<br><br>          -  Individuals diagnosed with generalized nodular PN, covering 2 separate body parts, and<br>             10 or more pruriginous nodules<br><br>          -  Severe itch due to PN<br><br>          -  Age 18 years and older at the time of consent, and a life expectancy of at least 18<br>             months.<br><br>        Exclusion Criteria:<br><br>          -  Pruritus due to localized PN (only one body part affected), or less than 10 nodules<br><br>          -  Pruritic dermatoses other than PN that were active/in need of treatment in the last 6<br>             months, such as atopic dermatitis, bullous pemphigoid or other dermatologic conditions<br>             that in the opinion of the Investigator could confound the ability to assess PN<br>             related itch.<br><br>          -  Unresolved acute secondary dermatoses active (unresolved) in the last (a) 4 weeks:<br>             localized contact dermatitis, environmental exposures, superficial burns, or viral<br>             exanthems; (b) 8 weeks: skin or environmental infestations, such as scabies, lice, or<br>             bed bugs.<br><br>          -  Other non-dermatologic disease that could be a potential cause of concomitant pruritus<br>             (e.g., thyroid disease, celiac disease, hepatitis C virus [HCV]) must either have<br>             resolved, been successfully treated (i.e., HCV RNA negative) or must be successfully<br>             managed with stable, optimized treatment (e.g., thyroid replacement, dietary<br>             management with resolution of symptoms, respectively) for at least 3 months prior to<br>             screening<br><br>          -  History of a major psychiatric disorder such as bipolar disorder or schizophrenia.<br>             History of substance abuse in the last 3 years. Individuals using sedating<br>             antidepressants. Individuals using non-sedating antidepressants must be on a stable<br>             dose for a minimum of 8 weeks prior to entering the study.<br><br>          -  Known intolerance (GI, CNS symptoms) or hypersensitivity/drug allergy to opioids.<br><br>          -  Use of certain concomitant medications and treatments within a period prior to the<br>             study, or requirement for these medications during the study:<br><br>               -  Within 14 days prior to screening: opiates, gabapentin, pregabalin, calcineurin<br>                  inhibitors, cannabinoid agonists, capsaicin, cryosurgery, topical doxepin,<br>                  thalidomide or methotrexate, antihistamines (systemic or topical), and topical<br>                  corticosteroids, cryotherapy.<br><br>               -  Within 4 weeks prior to screening: ultraviolet (UV)-therapy, exposure to any<br>                  investigational medication, including placebo<br><br>               -  Within 3 months prior to screening: Non-insulin biologics (including monoclonal<br>                  antibodies) that modify the immune system,<br><br>               -  Individuals taking monoamine oxidase inhibitors are excluded, as concomitant<br>                  opiate use may increase the risk for serotonin syndrome.<br><br>               -  Individuals who have previously received dupilumab or nemolizumab are excluded<br><br>          -  Myocardial infarction or acute coronary syndrome within the previous 3 months, as<br>             reported by the subject.<br><br>          -  Individuals with prolonged QTcF<br><br>        Individuals with HIV can be included if they meet the following criteria: (a) currently on<br>        a stable (> 6 months stable use) and well tolerated highly active antiretroviral therapy<br>        regimen; (b) CD4 count > 500 cells/mL; and (c) HIV ribonucleic acid (RNA) < 50 copies/mL<br>        documented for at least 6 months prior to enrollment.<br>