A 12-week, randomized, placebo-controlled trial assessing the safety and efficacy of oxymorphone extended release for opioid-naive patients with chronic low back pain.

Objective: Determine the efficacy and tolerability of oxymorphone extended release (OPANA ER) in opioid-naive patients with moderate to severe chronic low back pain (CLBP).

Design And Methods: Patients > or = 18 years of age were titrated with oxymorphone ER (5- to 10-mg increments every 12 h, every 3-7 days) to a well-tolerated, stabilized dose. Patients were then randomized to continue their oxymorphone ER dose or receive placebo every 12 h for 12 weeks. Oxymorphone immediate release was available every 4-6 h, as needed, for the first 4 days and twice daily thereafter.

Results: Sixty-three percent of patients (205/325) were titrated to a stabilized dose of oxymorphone ER, most (203/205) within 1 month. During titration, 18% discontinued from adverse events (AEs) and 1% from lack of efficacy. For patients completing titration, average pain intensity decreased from 69.4 mm at screening to 22.7 mm (p < 0.0001). After randomization, 68% of oxymorphone ER and 47% of placebo patients completed 12 weeks of double-blind treatment. Approximately 8% of patients in each group discontinued because of AEs. Placebo patients discontinued significantly sooner from lack of efficacy than those receiving oxymorphone ER (p < 0.0001). Pain intensity increased significantly more in the placebo group (least squares [LS] mean change 26.9 +/- 2.4 [median 28.0]) than in the oxymorphone ER group (LS mean change 10.0 +/- 2.4 [median 2.0]; p < 0.0001). Oxymorphone ER was generally well tolerated without unexpected AEs. Although limitations of a randomized withdrawal study include the potential for unblinding and opioid withdrawal in placebo patients, opioid withdrawal was limited to two patients in the placebo group and one in the oxymorphone ER group.

Conclusions: Stabilized doses of oxymorphone ER were generally safe and effective over a 12-week double-blind treatment period in opioid-naive patients with CLBP.