Goals of work: Inadequate analgesia and/or unmanageable adverse events frequently result in the need to rotate patients with cancer pain to a different opioid. The availability of a novel oral extended-release (ER) formulation of oxymorphone provides clinicians with another treatment option. In this study, we assessed the analgesic effectiveness and safety of the new oral ER formulation of oxymorphone following treatment with controlled-release (CR) morphine sulfate or oxycodone.
Patients and methods: Adults with moderate to severe cancer pain were stabilized for > or =3 days on morphine CR or oxycodone CR, and then treated for 7 days at their stabilized dose. Drug selection was based upon patients' previous use or investigator preference. Patients were then crossed over for 7 days of treatment at an estimated equianalgesic dosage of oxymorphone ER. Pain was assessed using a visual analog scale, and adverse events were recorded.
Main results: A total of 86 patients entered open-label treatment. Of 34 patients assigned to morphine CR and 52 assigned to oxycodone CR, 21 (61.8%) and 42 (80.8%) completed stabilization and began treatment with oxymorphone ER, respectively; 59 of 63 (93.7%) completed treatment with oxymorphone. There were no significant differences in daily pain intensity scores between oxymorphone ER and comparators (paired t -test). Rescue medication use, expressed as the percent of the daily dose of scheduled opioid, was greater during morphine CR treatment than after crossover to oxymorphone ER (25.2% vs 13.3%; P <0.05, Wilcoxon's test). The tolerability/safety profiles (e.g., nausea, drowsiness, somnolence) were similar for all opioids.
Conclusions: Cancer patients stabilized on morphine CR or oxycodone CR were safely and rapidly converted to a lower milligram dose of oxymorphone ER that provided adequate pain relief with comparable tolerability. These results justify additional trials with oxymorphone ER.