Spleen Tyrosine Kinase Inhibitor Benefits RA Patients
R788 found effective for rheumatoid arthritis patients not responding to methotrexate
WEDNESDAY, Sept. 22 (HealthDay News) -- A spleen tyrosine kinase (Syk) inhibitor significantly reduces rheumatoid arthritis (RA) disease activity in patients not responding to methotrexate, according to a study published online Sept. 22 in the New England Journal of Medicine.
Michael E. Weinblatt, M.D., of Brigham and Women's Hospital in Boston, and colleagues enrolled 457 patients whose RA was active in spite of long-term methotrexate therapy. The subjects were randomized for treatment with R788, an oral Syk inhibitor, at 100 mg twice daily or 150 mg once daily, or placebo. Treatment response was measured using American College of Rheumatology (ACR) criteria.
After six months of treatment, the researchers found that 67 percent of the subjects taking the 100 mg dosage and 57 percent taking the 150 mg dosage of R788 achieved 20 percent improvement on ACR-defined treatment response measures, compared to 35 percent for placebo. The results for 50 percent improvement were 43, 32, and 19 percent, respectively; and, for 70 percent improvement the results were 28, 14, and 10 percent, respectively (P = 0.34 for comparison of the 150 mg dose with placebo). Adverse events included diarrhea (19 percent of subjects taking the 100 mg dose versus 3 percent on placebo), upper respiratory infection (14 versus 7 percent), and neutropenia (6 versus 1 percent). Twenty-three percent of patients on R788 required initiation of or change in antihypertensive therapy, versus 7 percent on placebo.
"Additional studies will be needed to further assess the safety and efficacy of Syk-inhibition therapy in patients with RA," the authors write.
The study was supported by Rigel. The authors reported numerous financial relationships with pharmaceutical and/or medical device companies, including Rigel.