Source: Jpn J Clin Hematol  |  Posted 5 years ago

By Crystal Phend

SAN DIEGO, C.A. -- March 1, 2006 -- Opioid na?ve patients with chronic low back pain may get better relief from once daily morphine sulfate (Avinza) than twice daily oxycodone (OxyContin), according to a study presented here at the annual meeting of the American Academy of Pain Management (AAPM).

Morphine treated patients also had significantly lower daily morphine-equivalent doses compared to those in the oxycodone group.

"You don't need to give as much opioid [with morphine sulfate]], and it's always better to give less opioid," said co-author Richard Ghalie, MD, Vice President of Medical Affairs, Ligand Pharmaceuticals, San Diego, California, United States, in a presentation on February 23[^]rd[].

In the open-label study, opioid-na?ve patients with moderate to severe chronic low back pain were randomized to receive oxycodone or morphine sulfate. The 266 patients who completed the dose titration phase went on to the 8 week evaluation phase.

Of these, 174 entered the optional 4 month extension phase. Demographics in the extension phase were statistically different in the morphine and oxycodone groups: 68% versus 84% were Caucasian, 9 versus 7 years average duration of back pain, 23% versus 11% non-mechanical cause of back pain, and 43% versus 28% with nerve involvement, respectively.

The average morphine dose was 86 mg; the average daily oxycodone dose was 79.5 mg. Using the American Pain Society's conversion factor, patients in the oxycodone group received significantly more opioid daily (119 mg vs. 86 mg).

Brief pain inventory scores reported at monthly office visits were similar between treatment groups, Dr. Ghalie said.

Absolute changes in pain scores from baseline were about 1 point lower on a 10 point scale at the second, third and fourth monthly visits for patients in the morphine group, but this difference was significant only at the second and third visits. Dr. Ghalie said this finding narrowly missed significance at month 4 because the number of patients was getting smaller.

Sleep scores on the Pittsburg Sleep Quality Index were consistently lower for the morphine group, while the relative change from baseline on the same index was significantly better at month 1, according to Dr. Ghalie.

Patients in the two groups reported similar incidence and severity of adverse effects.

Dr. Ghalie said both drugs clearly work well, but one reason for differences in outcomes between the groups is that about a third of patients typically need three times daily dosing for oxycodone rather than the twice daily dosing indicated on the label.

[Presentation title: ACTION Study (AVINZA vs. OxyContin Comparator Trial In Opioid-Na?ve Patients) a Randomized, Open-label, Multicenter Study of Once-a-day AVINZA vs. Twice Daily OxyContin for the Treatment of Chronic Moderate to Severe Low Back Pain Final Report of the 16-Week Extension Phase. Poster 158]