Pfizer Inc said on Friday its Xeljanz rheumatoid arthritis drug succeeded in meeting primary and secondary goals of a pair of late stage clinical trials in ulcerative colitis, results that could help pave the way for an additional approval for the oral medicine.

The largest U.S. drugmaker said results of the two studies and data from two others will be used in its application to regulators seeking approval in ulcerative colitis (UC) for Xeljanz, known chemically as tofacitinib.

In the two Phase III studies, presented at a European medical meeting, Xeljanz reduced symptoms of moderate to severe UC and induced disease remission at significantly higher rates compared with a placebo.

In one study, 18.5 percent of patients who received 10 milligrams of Xeljanz twice a day achieved remission, including no rectal bleeding, after eight weeks versus 8.2 percent of patients who received a placebo.

In another study, 16.6 percent of Xeljanz patients achieved remission compared with 3.6 percent for placebo, researchers reported.

A significantly higher number of Xeljanz patients also experienced mucosal healing, a secondary goal of the trials.

A similar proportion of patients in the tofacitinib and placebo groups reported serious adverse side effects, the company said.

"Ulcerative colitis can be a difficult disease to manage, as many patients fail or become intolerant to conventional therapies," Dr. Geert D'Haens, a study investigator, said in a statement, adding that improvement in symptoms was observed as early as Week 2.

The trials included patients who had been previously treated with commonly used injectable biotech drugs as well as those who were not.

UC is a chronic, often debilitating inflammatory bowel disease that affects millions of people worldwide. Its symptoms can include abdominal pain, fever, weight loss and chronic, bloody diarrhea.