Rigel Pharma Shares Suffering After Phase 3 Study Failure

Rigel Pharmaceuticals, Inc. RIGL shares are on a free fall, pulling back to a three-month low, with the downside accompanied by huge volumes.

The company's announced that fostamatinib, its oral investigational candidate for immune thrombocytopenia failed to meet the primary end-point in a late-stage study.

Immune thrombocytopenia is a condition in which the immune system attacks and destroys the body's own blood platelets, leading to excessive bruising, bleeding and fatigue due to low platelet counts.

The primary endpoint of the Phase 3 clinical program of the study dubbed FIT was a stable platelet response. Stable platelet response was defined as platelet counts over 50,000/uL of blood on at least four of the last 6 scheduled clinical visits between week 14 and 24 of treatment.

The company noted that the results of the double-blind FIT 2 Phase 3 study showed 18 percent response rate for fostamatinib, which though consistent with the FIT 1 Phase 3 study, were not statistically significant, given the 4 percent of response rate seen in the placebo group.

However, the company clarified that when data from both studies were combined, the difference is statistically significant. The data from both studies and the open label extension study confirm the consistent benefits of fostamatinib in ITP, the company said.

At last check, Rigel Pharma shares were down 24.07 percent at $2.44.