Rigel Pharmaceuticals, Inc. Experimental Eye Drug R348 Fails Mid-Stage Study

Published: Aug 14, 2014

Rigel Pharmaceuticals, Inc. Experimental Eye Drug R348 Fails Mid-Stage Study Rigel Pharmaceuticals, Inc. Experimental Eye Drug R348 Fails Mid-Stage Study

August 13, 2014
By Jessica Wilson, BioSpace.com Breaking News Staff

Rigel Pharmaceuticals, Inc. , a South San Francisco-based drug-development company, today announced that it has stopped the Phase 2 clinical study of the drug R348 for the treatment of dry eye disease. The company’s share price dropped nearly 11% in pre-market trading in the wake of the news. Thus far today, the share price has continued to fall.

The drug R348, which targets the JAK/SYK signaling pathways and is referred to as an ophthalmic JAK/SYK inhibitor, failed to meet primary and secondary endpoints in the study. According to the company, “the endpoints were measured by changes in corneal fluorescein staining, conjunctival staining, tear production and dry eye symptom scores from baseline over 12 weeks of treatment versus placebo.” The drug, an eye drop formulation, was meant to reduce the inflammation that causes chronic dry eye and thus alleviate the symptoms of the disease, from which more than five million Americans suffer.

Less than two weeks ago, Rigel released its second quarter earnings for 2014. The company reported a net loss of $25.4 million, or $0.29 per share, compared to a net loss of $22.8 million, or $0.26 per share, in the same period of 2013. In the announcement, James M. Gower, chairman and chief executive officer of Rigel, said, "We anticipate reporting the top-line results from the Phase 2 study of R348 in patients with dry eye shortly.” The failure of the drug so soon after Gower’s optimistic prediction is surprising and will likely affect future earnings.

The disappointment of R348 is one in a string of recent drug failures for Rigel. In August 2013, Rigel ended its Phase 2 trial of the inhaled SYK inhibitor R343 for the treatment of asthma after it, too, failed to meet its primary and secondary endpoints. In Oct 2013, the company saw another drug, R333, flunk its trials. The drug R333 was developed to treat skin lesions in patients with discoid lupus, a chronic skin disease, and failed to achieve its primary endpoint. In addition, in June 2013, AstraZeneca stopped developing fostamatinib, a rheumatoid arthritis treatment, which the biopharmaceutical giant had licensed from Rigel in 2010.

Rigel has said that it will continue the Phase 2 study of R348 for dry eye in patients with graft versus host disease (GvHD). The company is also continuing its research on the drug fostamatinib, including a recently initiated Phase 3 study in patients with the bleeding disorder immune thrombocytopenic purpura (ITP) and a planned Phase 2 study in patients with IgA Nephropathy (IgAN), an autoimmune disease of the kidneys.

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