Rigel Welcomes Brian Kotzin, M.D. to Board of Directors

SOUTH SAN FRANCISCO, Calif., Aug. 25, 2017

"We are excited to welcome Dr. Kotzin to our board, and we feel confident that his leadership will be of great value to Rigel," said Raul Rodriguez, president and chief executive officer of Rigel. "We look forward to working with Dr. Kotzin and benefitting from his strategic counsel, as we continue to evolve our pipeline and move our new IRAK molecule into clinical development."

A board-certified rheumatologist and internist, Dr. Kotzin is currently Principal Fellow, Clinical Development at Nektar Therapeutics.  From 2004 to 2015, he was Vice President, Global and Clinical Development and Head, Inflammation Therapeutic Area at Amgen, directing the global development efforts for product candidates in the inflammation area. Before joining Amgen, Dr. Kotzin was the head of Clinical Immunology in the Department of Medicine and director of the Autoimmunity Center of Excellence at the University of Colorado Health Sciences Center in Denver. He earned his medical degree from Stanford and undergraduate degree in mathematics from the University of Southern California.  Dr. Kotzin has won numerous honors, including elected "Master" of the American College of Rheumatology, the Kirkland Scholar Award for Lupus Research, the Henry Claman Chair in Clinical Immunology, the Gretchen Kramer Award for Outstanding Contributions to Medicine, and Chairmanship of the National Institutes of Health Autoimmunity Centers of Excellence.

"I am very enthusiastic about joining Rigel to support its research and development efforts as it continues to advance its pipeline," said Dr. Kotzin. "I believe the IRAK program has significant potential for the treatment of autoimmune and inflammatory diseases, and I look forward to offering my insights and experience as they advance this program into the clinic next year."

About Rigel (www.rigel.com)
Rigel Pharmaceuticals, Inc. is a biotechnology company dedicated to discovering, developing and providing novel small molecule drugs that significantly improve the lives of patients with immune and hematological disorders, cancer and rare diseases. Rigel's pioneering research focuses on signaling pathways that are critical to disease mechanisms. The company's current clinical programs include clinical trials of fostamatinib, an oral spleen tyrosine kinase (SYK) inhibitor, in a number of indications. Rigel has submitted an NDA to the FDA for fostamatinib in patients with chronic or persistent immune thrombocytopenia (ITP). In addition, Rigel has product candidates in development with partners BerGenBio AS, Daiichi Sankyo and Aclaris Therapeutics.

Forward Looking Statements
This release contains forward-looking statements relating to, among other things, the ability of a Rigel IRAK molecule to be taken into the clinic as well as the potential of such molecules to treat autoimmune and inflammatory diseases. Any statements contained in this press release that are not statements of historical fact may be deemed to be forward-looking statements. Words such as "planned," "will," "may," "expect," "potential" and similar expressions are intended to identify these forward-looking statements. These forward-looking statements are based on Rigel's current expectations and inherently involve significant risks and uncertainties. Actual results and the timing of events could differ materially from those anticipated in such forward looking statements as a result of these risks and uncertainties, which include, without limitation, the FDA may not approve Rigel's submitted NDA; the availability of resources to develop Rigel's product candidates; Rigel's need for additional capital in the future to sufficiently fund Rigel's operations and research; the uncertain timing of enrollment and completion of and the results of clinical studies; market competition, risks associated with and Rigel's dependence on Rigel's corporate partnerships; risks related to changes in estimated cash position based on the completion of financial closing procedures and the audit of Rigel's financial statements; as well as other risks detailed from time to time in Rigel's reports filed with the Securities and Exchange Commission, including its Quarterly Report on Form 10-Q for the period ended June 30, 2017. Rigel does not undertake any obligation to update forward-looking statements and expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein.

Contact: Ryan D. Maynard
Phone: 650.624.1284
Email: invrel@rigel.com