OXN PR Tablet 5/2.5 mg and20/10 mg PK Study in Chinese Moderate to Severe Chronic Non-malignant Patients

This is an open-label, randomized, single-dose, parallel group study. The objectives of this study are to assess pharmacokinetics of oxycodone and naloxone from oxycodone/naloxone (OXN) prolonged release (PR) tablet 5/2.5 mg (OXN 5/2.5) and 20/10 mg (OXN 20/10) in Chinese patients with moderate to severe chronic non-malignant pain.

It will be conducted to assess the pharmacokinetics of OXN 5/2.5 and OXN 20/10 tablets. Subjects will be allocated to a sequence of two strength group in accordance with a random allocation schedule (RAS) in a 1:1 ratio.

Subjects will attend a screening visit within 14 days of the first (OXN) dosing day (Day 1).

Eligible subjects will then check into the study unit on the day before OXN dosing (Day -2). Subjects will be administered their OXN dose the next 2 morning (Day 1), following an overnight fast.

Eligibility Criteria:
Inclusion Criteria:

1. Adult Chinese patients with moderate to severe chronic non-malignant pain.
2. Male and female subjects with age range 18 to 65 years (including 18 and 65), body weight ≥ 45kg and BMI range 18 to 30 (including 18 and 30).
3. Patients who should rate their pain (Pain Intensity Scale -"average pain" over the last 24 hours) as ≥4 on 0-10 scale.
4. Patients, who are able to read, understand and sign written informed consent prior to study participation and are willing to follow the protocol requirements.
5. Females of childbearing potential and less than one year post-menopausal must have a negative serum pregnancy test during screening visit and at check-in and be non-lactating. In addition, they must be willing to use adequate and reliable contraception throughout the study. Highly effective methods of birth control are defined as those which result in a low failure rate (i.e. less than 1% per year) when used consistently and correctly such as sterilization, implants, injectables, combined oral contraceptives, some IUDs (intrauterine Device, hormonal), sexual abstinence or vasectomised partner.

Exclusion Criteria:

1. Females who are pregnant (positive β-human chorionic gonadotrophin \[HCG\] test) or lactating.
2. Use of opioid or opioid antagonist-containing medication in the 30 days before the start of the study.
3. Known sensitivity to oxycodone, naloxone, or related compounds.
4. Subjects with clinically unstable respiratory disease, dysfunction of the biliary tract, thyroid disease, adrenal cortical insufficiency, prostatic hypertrophy requiring intervention (medication or surgical) or renal artery stenosis, or any other medical condition, that, in the opinion of the investigator or the sub-investigator, precludes entry into this study.
5. Subject who have a past (within 5 years) history of malignant neoplasm including leukemia and lymphoma.
6. The electrocardiogram examination results are abnormal, in the opinion of the investigator or the sub-investigator, and are clinical significance.
7. Subjects with abnormal liver function (values exceed the upper limit of normal for AST, ALT or total bilirubin during the Screening Period) or abnormal renal function (values exceed the upper limit of normal for serum creatinine during the Screening Period).
8. Patients with a contraindication to the study medication.
9. Subjects who have a psychiatric disorder such that participation in the study may, in the opinion of the investigator or the sub-investigator, pose an unacceptable risk to the subject.
10. Subjects who have a current or past (within 5 years) history of substance or alcohol abuse, or subjects who give a positive result in drug abuse test during the Screening Period, or subjects who, in the opinion of the investigator or the sub-investigator, have demonstrated addictive or substance abuse behaviors.
11. Subjects with uncontrolled seizures or convulsive disorder.
12. Subjects who will receive any interventional therapy (surgery, paracentesis,etc) for arthritis during the study period.
13. History of or any current conditions that might have interfered with drug absorption, distribution, metabolism or excretion.
14. Any history of frequent nausea or emesis regardless of aetiology.
15. Participation in any clinical drug study during the 3 months preceding the initial dose in this study.
16. Use of any medication including vitamins, herbal and/or mineral supplements during the course of the study, other than Vitamin D, calcium supplements and continued use by females of contraceptive medication or HRT.
17. Consumption of alcoholic beverages within 48 hours before study drug administration, and refusal to abstain from alcohol until at least 48 hours after the last study drug administration.
18. Blood or blood products donated within 90 days prior to study drug administration or anytime during the study, except as required by this protocol.
19. Positive results of urine drug screen(for opioids, barbiturates, amphetamines, cocaine metabolites, methadone, diazepam and cannabinoids), alcohol breath test, hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (Ab), human immunodeficiency virus (HIV) test or qualitative syphilis tests.
20. Patients with moderate to severe hypohemia (HGB\<90g/L during the screening).