A Study to Evaluate Tapentadol (CG5503) in the Treatment of Chronic Tumor-Related Pain Compared With Placebo and Morphine

Inclusion Criteria

* Male and non-pregnant, non-lactating female subjects.
* Of at least 18 years of age with chronic malignant tumor-related pain with a mean pain intensity (NRS) of 5 points or higher.
* Subjects who are opioid-naïve or pretreated with an equianalgesic dose range equivalent of up to 160 mg oral morphine per day and are dissatisfied with prior treatment.
* Women must be postmenopausal, surgically sterile, or practicing or agree to practice an effective method of birth control throughout the trial.
* Expected course of the disease and the pain that would permit compliance with the trial protocol over the entire trial period.

Exclusion Criteria

Key Exclusion Criteria:

* Subjects will be excluded from the study if they have a history of seizure disorder or epilepsy;
* known history and/or presence of cerebral tumor or cerebral metastases.
* history of alcohol or drug abuse;
* uncontrolled hypertension,
* clinical laboratory values reflecting severe renal insufficiency,
* moderate or severe hepatic impairment,
* hepatitis B or C, HIV,
* inadequate bone marrow reserve
* currently treated with radiotherapy,
* pain-inducing chemotherapy,
* anti-parkinsonian drugs, neuroleptics, monoamine oxidase inhibitors, serotonin norepinephrine reuptake inhibitor (SNRI) or any other analgesic therapy than investigational medication or rescue medication during the trial.
* selective serotonin reuptake inhibitor (SSRI) treatments are allowed if taken for at least 30 days before the screening period of the study at an unchanged dose.