A Phase III Clinical Study of KW-2246 for Breakthrough Pain in Cancer Patients

Inclusion Criteria: At the time of obtaining written informed consent * Provide written informed consent to participate in the study on a voluntary basis. * Between the ages of 20 and 80 years (inclusive). * Outpatients who live with a caregiver such as a family member, or inpatients. * Regularly receiving one of the following opioid analgesics: sustained-release oral morphine, sustained-release oral oxycodone, and fentanyl transdermal patch. * The daily dosage of the regular opioid analgesic regimen can be maintained constant from the baseline period through the end of the study as determined by the investigator. * Require rescue medication at least 0.5 times (at least once every two days) but not more than three times per day on average as determined by the investigator. * Performance Status (ECOG) of 3 or less at the time of giving written informed consent.Be able to receive diary training and have the ability to properly complete diaries as determined by the investigator. * Have a life expectancy of at least three months as determined by the investigator. * Be able to receive diary training and have the ability to properly complete diaries as determined by the investigator. At the time of randomization * The "regular opioid analgesic" being used at the time of giving written informed consent has been taken at a fixed dosage throughout the baseline period. * The "immediate-release morphine" being used at the time of giving written informed consent (Opso® (morphine hydr…