Oxymorphone Extended Release in Patients With Cancer or Neuropathic Pain

Inclusion Criteria: * ≥ 18 years of age or older, with moderate to severe chronic malignant and/or neuropathic pain of at least 3 months duration and either: 1. have an initial pain intensity score of greater than 4 on a 10-point scale using BPI Question 5, if sub-optimally responding to their current analgesic regimen, or 2. have intolerable side effects to one or more components of their current opioid-containing analgesic regimen. * Currently receive a stable (at least 2 weeks duration) analgesic regimen * If female, must be practicing abstinence or using a medically acceptable form of contraception (e.g., intrauterine device, hormonal birth control, or double barrier method). * Understand written and spoken English * Have been informed of the nature of the study and provided written informed consent Additional Inclusion Criteria for Cancer Patients Only: * Have a life expectancy of at least 12 months Additional Inclusion Criteria for Neuropathic Patients Only: * Have a diagnosis of: * post-herpetic neuralgia (PHN) * diabetic neuropathy (DN) * complex regional pain syndrome (CRPS) * HIV neuropathy * idiopathic sensory neuropathy * traumatic peripheral neuropathy * central neuropathic pain condition (spinal cord injury, post-stroke pain), OR * other peripheral neuropathy (upon mutual agreement of the sponsor and investigator). Exclusion Criteria: * Have a positive pregnancy test (females only) * Have a history of or active asthma or emphysema * Have clinically significant hepatic impairment * Have a history of alcohol or substance abuse within the last 3 years * Have a history of opioid abuse within 6 months prior to study entry * Have a known allergy or significant reaction to opioids, including codeine * Have a known oxymorphone sensitivity or allergy * Have received an investigational drug or product or participated in an investigational drug study within a period of 30 days prior to receiving study medication