Effect of tofacitinib in synovial response of rheumatoid arthritis patients

The authors analyzed the effect of tofacitinib (Xeljanz) in controlling inflammation of the synovium (joint lining) in rheumatoid arthritis (RA).

In RA, the immune system begins attacking healthy tissue the way it normally attacks viruses or bacteria. This can cause inflammation, leading to chronic pain.

In several studies, tofacitinib alone or in combination with other RA drugs has shown effectiveness in reducing the signs and symptoms of RA. It works by blocking a certain protein, named Janus kinase (JAK), in the body that contributes to inflammation. Since JAK  is involved in rheumatoid synovitis (inflammation of synovium), the effectiveness tofacitinib in controlling this condition needs to be investigated.

The authors aimed to investigate the effect of tofacitinib in reducing rheumatoid synovitis.

29 patients were included in this 28-day study. All patients had inadequate response to methotrexate (Trexall) treatment previously.15 patients received tofacitinib plus methotrexate (Group 1).14 patients received a placebo (a substance with no therapeutic effect) plus methotrexate (Group 2).

On day 28, 11 patients in Group 1 had moderate to good EULAR response. This was compared to 1 patient in Group 2. The average decrease in DAS28 score from the beginning of the study to day 28 was 1.65 points in Group 1. In Group 2, the score remained almost unchanged.

Levels of several proteins involved in inflammation of the synovial lining were reduced in patients in Group 1, but not in Group 2. Blood level of the inflammatory protein CXCL10 were significantly reduced by treatment with tofacitinib, compared to placebo. 

The authors concluded that tofacitinib was possibly involved in JAK-mediated inflammation in rheumatoid synpovitis.

A larger patient population is needed for the results to be widely applied.