Fostamatinib Safe, Not Effective in Rheumatoid Arthritis
Among patients unresponsive to biologic agents, fostamatinib may help certain subgroups
MONDAY, Feb. 21 (HealthDay News) -- Fostamatinib disodium (R788), an oral spleen tyrosine kinase inhibitor, is safe but ineffective for treatment of patients with rheumatoid arthritis (RA) who failed biologic therapies, according to a study published in the February issue of Arthritis & Rheumatism.
Mark C. Genovese, M.D., of Stanford University in Palo Alto, Calif., and colleagues investigated the efficacy and safety of fostamatinib in a double-blind, placebo-controlled study. A group of 229 patients with active RA who failed to respond to biologic therapies were randomized to receive 100 mg fostamatinib or placebo. The primary end point was the American College of Rheumatology 20 percent improvement (ACR20) response after three months. Secondary end points included changes in inflammation and damage assessed by magnetic resonance imaging (MRI) and changes in the disease activity score.
The researchers found no significant difference in the ACR20 response between fostamatinib and placebo groups; although, there was a meaningful difference in the ACR20 among patients who had entered the study with elevated C-reactive protein. Secondary outcomes were different between the groups: the fostamatinib group showed improved synovitis scores on MRI and in C-reactive protein. Outcomes may have been affected by baseline differences in steroid use, prior biologic use, and MRI synovitis scores.
"Safety results appeared to suggest that 100 mg twice a day of R788 was a tolerable dose for chronic administration in RA. There appears to be sufficient grounds to study R788 in this refractory population again, with some important lessons learned from this phase II study," the authors write.