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OPANA® ER improves pain quality measures in opioid-experienced patients with chronic low back pain
Arnold R. Gammaitoni, PharmD1, Errol M. Gould, PhD2, Harry Ahdieh, PhD1, and Tina Ma, PhD1. (1) Endo Pharmaceuticals Inc., 100 Endo Blvd., Chadds Ford, PA 19317, (2) Medical Affairs, Endo Pharmaceuticals, Inc., 100 Endo Blvd., Chadds Ford, PA 19317
The Pain Quality Assessment Scale (PQAS) is a validated tool for evaluating the multidimensional nature of pain; it was used to characterize pain qualities in patients with moderate to severe chronic low back pain (CLBP) and to assess changes in pain qualities during placebo-controlled, double-blind treatment with OPANA® ER (oxymorphone extended-release). At screening, adult opioid-experienced patients were evaluated on 20 pain qualities (PQAS-20) with an 11-point scale (0= no pain and 10= worst pain imaginable for each question). Patients were titrated to a stable dose of OPANA® ER given every 12 hours that reduced average pain intensity to ≤40 mm (100-mm Visual Analog Scale). Stabilized patients (143/251; 57%) experienced large decreases in the most severe pain qualities; “sharp”, “intense”, “aching”, “unpleasant”, and “intense deep” qualities decreased from mean values ranging from 6.9-8.0 at screening to 2.6–3.6 at stabilization. Similarly, the mean PQAS-20 score decreased from 101 to 41 (P<0.001). During titration, commonly reported adverse events (AEs) were nausea (19.6%), constipation (11.6%), headache (11.6%), and somnolence (11.2%). Following titration, stabilized patients were randomized to double-blind treatment for 12 weeks with their stabilized dose of OPANA® ER or placebo. The placebo group experienced clinically significant increases in the same pain qualities that had been severe before titration with OPANA® ER. Mean increases from baseline were 2.8 [“intense deep” and “aching”] and 3.4 [“unpleasant”] for placebo versus 0.4 [“intense deep”], 0.5 [“aching”] and 0.6 [“unpleasant”] for OPANA® ER. Commonly reported AEs for OPANA® ER and placebo groups were pain exacerbation (5.7% and 4.2%, respectively) and constipation (5.7% and 1.4%, respectively). In this study, the PQAS identified the most severe pain qualities experienced by patients with CLBP. Titration with OPANA® ER improved severe pain qualities and these effects were verified in a 12-week, placebo-controlled, double-blind trial. Research funded by Endo Pharmaceuticals Inc.