Eli Lilly and Co.‘s new antidepressant Cymbalta was shown in a small clinical trial to be effective in reducing pain in women suffering from fibromyalgia, a chronic disorder that causes widespread pain in the muscles and soft tissues, researchers said.

The results of the 12-week study of 354 women, who took either Cymbalta once or twice a day compared with those taking a placebo, are scheduled to be presented later this week at the American College of Rheumatology annual meeting in Texas.

Fibromyalgia affects about six million Americans, most of them women, Lilly said.

More than half of the patients treated with 60 milligrams of Cymbalta responded to treatment after 12 weeks, compared to one third of those taking sugar pills, researchers said.

They said 44 percent of patients taking Cymbalta reported a sustained reduction in pain compared with 19 percent taking a placebo.

Roughly one-third of the 354 women in the study received Cymbalta once a day, one-third took the drug twice a day and one-third received a placebo, a Lilly spokesman said.

The effect of both doses of Cymbalta on significant pain reduction was independent of the drug’s effect on mood and the presence of major depression in patients, researchers concluded.

Cymbalta raises the level of two chemicals in the brain, serotonin and norepinephrine. Many scientists believe it is norepinephrine that is mainly responsible for the effect on pain.

In addition to treating depression, Cymbalta last month was approved by U.S. regulators for pain associated with nerve damage in diabetics.

Lilly has not yet said whether it planned to use data from the new study as a basis for seeking expanded approval for Cymbalta to treat fibromyalgia.