Rigel's Bleeding Disorder Drug Flunks Phase III Test, Stock Tanks

Rigel's Bleeding Disorder Drug Flunks Phase III Test, Stock Tanks October 20, 2016
By Alex Keown, BioSpace.com Breaking News Staff

SOUTH SAN FRANCISCO – Shares of Rigel Pharmaceuticals are down more than 24 percent after the company announced its Phase III program for fostamatinib in adult chronic/persistent immune thrombocytopenia did not meet its primary endpoints. Despite the failure, the company said it intends to discuss options with regulators at the U.S. Food and Drug Administration.

This morning the company said the difference between patients treated with fostamatinib, an oral spleen tyrosine kinase (SYK) inhibitor, and placebo did not reach statistical significance. The primary endpoint in the study was a stable platelet response, defined as platelet counts greater than 50,000/uL of blood on at least four of the last six scheduled clinic visits between weeks 14 and 24 of treatment. The company said in the FIT 2 study, the fostamatinib response rate was 18 percent, which was consistent with the recent FIT 1 study. In the Fit 2 study, one patient in the placebo group achieved a stable platelet response, which means the difference between those on treatment and those on placebo did not reach statistical significance, the company said. However, Rigel said when data from both studies are combined, the difference is statistically significant. Data from both FIT Phase III studies and the open-label extension study demonstrates the consistent benefit of fostamatinib in ITP, Rigel said.

demonstrates the consistent benefit of fostamatinib in ITP, Rigel said. "We believe that the totality and consistency of data from the FIT Phase III program, which included two Phase III studies and one long-term extension study, strongly supports a clear treatment effect, with a sustained clinical benefit of fostamatinib," Raul Rodriguez, president and chief executive officer of Rigel, said in a statement. "We are encouraged by these results and believe that the risk/benefit ratio for fostamatinib is positive for patients with chronic/persistent ITP, a population with a serious unmet medical need. As a result, we will continue to pursue this opportunity. Our next step is to seek feedback from the FDA."

The company did say the safety profile of the experimental treatment was consistent with previous trials. The most frequent adverse events were gastrointestinal-related. However, Rigel said that The U.S. Food and Drug Administration (FDA) granted fostamatinib Orphan Drug designation. The drug is believed to treat the underlying autoimmune mechanism of ITP. In ITP, the patient’s blood platelets are attacked by the immune system. It affects about 50 to 60,000 adults in the U.S. Current treatments include steroids, blood platelet production boosters (TPOs) and splenectomy. Early data of fostamatinib has shown that 18 percent of patients taking the drug in the trials achieved a stable platelet response.

While Rodriguez put a positive spin on the trial, investors have not been convinced, given the massive sell-off of stock this morning. Shares of Rigel are trading at $2.40 as of 11:58 a.m.

In September, the company slashed 38 percent of its workforce as part of a restructuring program. The restructuring plan included a shift from a research-and-discovery company to a commercial organization. Part of that reorganization means the company slashed 38 percent of its workforce, 46 people. The reorganization is expected to save the company between $17 and $20 million annually.

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