A Study of JNS020QD in Patients With Chronic Pain

Inclusion Criteria: * Chronic pain that requires opioid analgesics and that has persisted for 12 weeks or longer before giving the consent * Patients who received any of the following opioid analgesics at a stable dose for the treatment of chronic pain for 7 days or longer before giving the consent (excluding rescue dose): oral codeine phosphate; oral morphine hydrochloride; fentanyl transdermal; combination tablet of tramadol hydrochloride and acetaminophen; buprenorphine transdermal patch * Patients who received 2 or less rescue doses per day during the 7 days before giving consent * Patients whose mean pain intensity throughout the day of giving the consent is 45 mm or less on the visual analogue scale (VAS) * Male and female patients surgically sterile, abstinent, or practicing an effective method of birth control. Female patients have a negative pregnancy test result at screening. Male patients cannot donate sperm during the study and for 3 months after receiving the last dose of study drug Exclusion Criteria: * Other painful conditions which may interfere with the efficacy evaluation (eg bone fracture, rheumatoid arthritis) * Major surgery within 30 days before screening, or not fully recovered from surgery, or planned surgery during the time of the study * Pain that is considered mainly psychogenic * Uncontrolled/clinically significant arrhythmia * Hepatic function disorder such as fulminant hepatitis and hepatic cirrhosis, or renal impairment such as nephritic syndrome, acute or chronic renal failure * Any other condition that, in the opinion of the investigator, would compromise the best interest of the patient or that could prevent, limit, or confound the protocol-specified assessments