A Study Using fMRI Imaging to Evaluate the Effect of NKTR-181 on Brain Activity in Healthy, Non-physically Dependent Recreational Opioid Users.
Condition: Moderate to Severe Chronic Pain
MeSH terms: Chronic Pain
Intervention: NKTR-181; Oxycodone IR
Intervention description: A combination of NKTR-181 and oxycodone IR placebo; A combination of oxycodone IR and NKTR-181 placebo
Intervention MeSH terms: Oxycodone
Phase: Phase 1
Study type: Interventional
Primary purpose: Basic Science
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: A double-blind, double-dummy, parallel-group, randomized, positive control study.
Masking: Triple (Participant, Care Provider, Investigator)
Enrollment: 8.0
Sex: All
Minimum age: 18 Years
Maximum age: 60 Years
Healthy volunteers: Accepts Healthy Volunteers

Summary:

      The main purpose of this study is to evaluate the effect of NKTR-181 on brain activity in
      healthy, non-physically dependent recreational opioid users. This study will last about 88
      days for each participant.
    

Eligibility criteria:

        Key Inclusion Criteria:

          -  Healthy male and female recreational opioid users, 18-65 years of age inclusive.

          -  Body Mass Index (BMI) between 19.0 to 45.0kg/m2

          -  Have at least one urine drug screen positive for opioids during Screening to confirm
             recreational opioid use. Subjects testing positive for methadone or buprenorphine
             prescribed for treatment will be excluded.

          -  Subjects must agree to practice adequate contraception as outlined in the protocol.

        Key Exclusion Criteria:

          -  Any metal fragments or other bodily metal that would pose a risk to subjects during
             MRI scanning as determined by the MRI technologist and/or MRI physicist

          -  Any clinically significant disease or condition that might compromise the
             cardiovascular, hematological, renal, hepatic, pulmonary, endocrine, central nervous,
             or gastrointestinal systems or other conditions that may interfere with the
             absorption, distribution, metabolism, or excretion of the study drug or would place
             the subject at increased risk

          -  History of clinically significant acute asthma or other obstructive airway disease
             requiring daily controller medication or any condition that may increase the risk for
             respiratory depression

          -  Current neurologic conditions such as convulsive disorders, or history of severe head
             injury.

          -  Any current DSM-5 axis I psychiatric disorder or neurological disorder requiring
             ongoing treatment

          -  Current substance use disorder (moderate to severe), other than Opioid, Nicotine, THC
             (tetrahydrocannabinol), cocaine, or caffeine as defined by DSM-5

          -  Physical dependence of opioids

          -  History of claustrophobia or any other psychiatric disorder that would preclude
             subject tolerance of MRI procedures.

          -  Current use of any medication that could affect central nervous system blood flow
             (e.g. certain cardiovascular medications, triptan migraine medications)

          -  Clinical Opiate Withdrawal Scale (COWS) score of greater than 5 during screening or
             prior to first scan.

          -  Positive urine drug screen for buprenorphine or methadone immediately prior to the
             first scan.