Rigel leaps as fostamatinib meets primary endpoint in Phase III Study in chronic ITP

Clinical-stage US drug developer Rigel Pharmaceuticals (Nasdaq: RIGL) saw its share soar nearly 49%% to $3.93 on heavy trading volume by close of trading on Tuesday, after the company reported that its investigational drug fostamatinib, for patients with an autoimmune platelet disease, achieved its goals in a Phase III study.

The company said fostamatinib, its oral spleen tyrosine kinase (SYK) inhibitor, met the primary endpoint in the first of two double-blind studies in the FIT Phase III clinical program for the treatment of adult chronic/persistent immune thrombocytopenia (ITP).  The study (n=76) showed that 18% of patients receiving fostamatinib achieved a stable platelet response compared to none receiving a placebo control (p=0.0261).  A stable platelet response was defined as achieving greater than 50,000 platelets per uL of blood on at least four of the last six scheduled visits between weeks 14 and 24 of treatment. The results from the second FIT Phase III study are expected in October/November 2016.

The most frequent adverse events were gastrointestinal-related, and the safety profile of the product was consistent with prior clinical experience, and no new or unusual safety issues were discovered.