Update on results of phase III trial of R 788 (fostamatinib) in thrombocytopenic purpura- Rigel Pharma

Rigel Pharmaceuticals announced updates from the clinical program of R 788 (fostamatinib) in patients with chronic immune thrombocytopenic purpura (ITP). Previously released results from the FIT Phase III clinical studies (047, 048) of fostamatinib in chronic ITP demonstrated that patients who responded to fostamatinib have a timely, robust, and sustained response to treatment. As of September 2016, the open-label, long-term extension study (049), was tracking the experience of 124 patients who opted to receive treatment with fostamatinib after their participation in either Study 047 or Study 048. Seventeen patients who achieved a stable response to fostamatinib in the parent studies enrolled in Study 049. As of September 2016, responders who enrolled in the 049 study had maintained a median platelet count of 106,500/uL over this extended period of time. These patients have been on fostamatinib treatment for a median of 16 months as of September 2016.

In addition, there were now 41 out of 44 former placebo patients who had been treated with fostamatinib for a minimum of 12 weeks. Of those, 22% (9/41, p=0.0078) achieved a prospectively defined stable platelet response, which Rigel believes further validates fostamatinib as a potential new treatment option for some patients with this serious disease. Rigel also announced its calculations of an overall response rate for Study 047 and Study 048 by combining stable and transient responders. The overall response rate to fostamatinib is 29% (29/101) compared to 2% (1/49) for placebo (p=<0.0001).>