Efficacy and safety evaluation of once-daily OROS hydromorphone in patients with chronic low back pain: a pilot open-label study (DO-127).

OBJECTIVE

To evaluate the safety, tolerability, and efficacy of once-daily osmotic controlled-release oral delivery system (OROS) hydromorphone in patients with chronic low back pain of moderate-to-severe intensity.

RESEARCH DESIGN AND METHODS

This was a 6-week, multicenter, nonrandomized, noncomparative, open-label, repeat-dose study of chronic (> or = 6 weeks) low back pain. The study comprised three periods: prior opioid stabilization (2-7 days); OROS hydromorphone conversion, titration, and stabilization (3-14 days); and OROS hydromorphone maintenance (28 days). Patients were evaluated weekly. Baseline pain assessment was performed at the end of prior opioid stabilization. For pain relief rating, endpoint was defined as the mean pain relief score from the last 2 nonmissing days before study termination. For other assessments, endpoint was defined as the last post-baseline evaluation.

RESULTS

Of the 207 patients who received the study drug, 131 completed the trial. Scores (mean +/- SD) for Brief Pain Inventory 'worst pain in the last 24 hours' decreased significantly from baseline to endpoint (-0.8 +/- 2.06, p < 0.0001). The proportions of patients and investigators rating the global effectiveness as good, very good, or excellent increased from 31.6% at baseline while patients were on prior opioids to 63.2% at endpoint while patients received OROS hydromorphone, and from 29.8% at baseline while patients were on prior opioids to 65.8% at endpoint while patients received OROS hydromorphone, respectively. Daily pain relief ratings also increased significantly (+0.26 +/- 1.084, p = 0.0008). Significant improvements in health-related quality of life and sleep problems were observed. Adverse events were mild to moderate in severity; the most common of these were constipation, nausea, headache, and somnolence. The limitations of this study include its pilot-type design and the lack of comparison of OROS hydromorphone with a placebo or another drug. Additional comparative and longer-term studies are needed to confirm these findings.

CONCLUSIONS

OROS hydromorphone may be an effective treatment for chronic low back pain of moderate-to-severe intensity. Adverse events were typical of those associated with opioid therapy.