When immune systems attack, Rigel Pharmaceuticals wants to be there. The drug discovery and development firm focuses its research and development efforts on inflammatory/autoimmune, muscle, and metabolic diseases. Drugs in development include candidates for treating rheumatoid arthritis, psoriasis, muscle wasting, multiple sclerosis, and transplant rejection. Rigel prefers to collaborate with larger pharmaceutical companies in the development of its drug candidates. Rigel Pharmaceuticals went public through a $140 million IPO in 2011. The company intends to use the funds to further develop its current pipeline and to form additional collaborations with larger pharmaceutical companies.