Pfizer's oral RA drug passes mid-stage test

Pfizer is claiming success in a mid-stage trial of an experimental oral drug for rheumatoid arthritis, saying the data has helped it hone in on the doses that will be tested in an upcoming Phase III study of CP-690,550.

The drug is a Jak-3 inhibitor designed to block enzymes that play a key role in the inflammatory disease. Researchers for the pharma giant say that the therapy, which is taken twice a day, demonstrated a statistically significant response when compared to a placebo. The goal of the trial, which tested four doses, was a 20 percent improvement (ACR 20) in tender and swollen joints.

At 10 and 15 mgs, 75.4 percent of the patients hit that goal--compared to 28.8 percent of the patients in the placebo arm. At 3 mg the ACR 20 response rate was 49 percent and at 5 mg the rate was 63.3 percent. The data was presented at the European League Against Rheumatism meeting in Copenhagen. Significant response rates were also seen for ACR 50 improvements in symptoms at the three highest doses. Researchers now plan to take the 5 mg and 10 mg doses into a late-stage study. 

- read the story from Reuters