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