INDIANAPOLIS, Indiana—Eli Lilly and Company researchers reported new data showing that patients with chronic low back pain on Cymbalta^® (duloxetine HCl) maintained reductions in pain for 41 weeks. Patients who initially responded to duloxetine also had a further statistically significant reduction in pain. The company said that the data was presented at the sixth triennial congress of the European Federation of Chapters of the International Association for the Study of Pain (EFIC(R)).

The open-label 41-week extension study enrolled 181 patients with chronic low back pain taking duloxetine 60 mg or 120 mg once daily after completing a 13-week, placebo-controlled, acute phase study. Maintenance of effect was assessed in the responders: 58 duloxetine patients who had experienced at least 30% pain reduction from baseline during the 13-week, placebo-controlled acute phase of the study.

The most common adverse events included headache, nausea, upper abdominal pain, excessive sweating (hyperhidrosis), back pain, diarrhea, and fatigue, and were similar to those seen in previous duloxetine studies, the company said. Eighteen discontinued due to adverse events during the extension phase.

"Chronic low back pain is a painful and debilitating condition and this study is an important step in the fight against it," said Vladimir Skljarevski, MD, lead study author and a neurologist and medical fellow at Lilly Research Laboratories in Indianapolis.

Maintenance of effect was assessed in 58 duloxetine patients who were responders (greater than or equal to 30% reduction in Brief Pain Inventory (BPI) average pain) at the end of the acute phase. If the upper bound of the 97.5% Confidence Interval (CI) of the mean change from the end of the acute phase for the BPI average pain was less than the pre-specified margin of 1.5, then maintenance of effect was established.

Lilly is seeking approval for Cymbalta for osteoarthritis and for low back pain. The drug is approved in the United States for the acute and maintenance treatment of major depressive disorder, the acute treatment of generalized anxiety disorder, the management of diabetic peripheral neuropathic pain, and the management of fibromyalgia,