• Rigel is focusing its oral Janus Tyrosine Kinase 3 (JAK3) program on the potential inhibition of autoimmune diseases such as psoriasis and rheumatoid arthritis (RA).


• Psoriasis is a lifelong autoimmune disease of the skin that affects approximately 7.5 million people in the United States and an estimated 125 million people worldwide. About 10-30% of patients with psoriasis also develop psoriatic arthritis, which causes pain, swelling and stiffness of the joints.


• RA affects approximately 1% of the population worldwide -- approximately 2.1 million Americans -- and is a debilitating and degenerative atuoimmune disease. The worldwide market for innovative RA drugs is projected to reach $13 billion by 2008.


• Rigel's R348 is a selective, potent inhibitor of Janus Tyrosine Kinase 3 (JAK3). JAK3 is critical to immune system activation and is an attractive target because its expression is limited to key cells in the immune system, particularly T-cells, which mediate these diseases.

• Initiated a Phase 1 clinical trial in January 2008.
• In preclinical studies, R348 was shown to be effective in models of psoriasis, as well as reducing arthritic symptoms, bone destruction and swelling in models of RA.

• We expect to initiate a POC study in '08 in Psoriasis.

• Rigel Announces Initiation of Phase 1 Clinical Trial of R348 for Rheumatoid Arthritis, Psoriasis and Other Immune Disorders
  
• Rigel Announces Selection of R348, a Novel JAK3 Inhibitor, for advanced preclinical development
  

Current therapeutic approaches
Current treatments for these diseases include steroids, methotrexate, and various injectable biologic agents. Our product candidate, R348, is believed to be orally bio-available and may provide an attractive alternative or supplement to currently used agents.