NEW YORK (AP) -- Drugmaker Pfizer Inc. said Wednesday that a dose of its rheumatoid arthritis drug Xeljanz fared on par with another drug when tested in late-stage research as a possible treatment for a form of psoriasis.
The New York company said early study results showed that a 10-milligram dose of the pill, known chemically as tofacitinib, taken twice daily proved to be not inferior to a dose of Enbrel, an established treatment for the disease. A 5-milligram dose did not meet the study's non-inferiority criteria, meaning that researchers saw no statistical evidence that the effectiveness of the drug at that dose was equivalent to Enbrel.
A separate study showed that patients taking the drug fared better after administration of the treatment stopped than those taking a placebo.
Pfizer is conducting five late-stage studies of the drug and will use that research to apply for approval for the additional use. It said initial results from other studies should be released by next year's second quarter.
Psoriasis is a chronic, inflammatory disease that affects the skin, nails and joints. It affects about 175 million people worldwide.
Xeljanz is viewed as a potential big seller for Pfizer, the world's second-largest drugmaker. Regulators in the United States, Japan and other countries have approved it as a treatment for rheumatoid arthritis, a condition in which the immune system mistakenly attacks tissue in the body, primarily the joints, limiting mobility and sometimes leaving fingers bent at uncomfortable angles.
Shares of Pfizer added 2 cents to $28.26 Wednesday morning, while the Dow Jones Industrial Average was flat. The stock has traded between $23.55 and $31.15 over the past year.