threonine protein kinase 1 (RIPK1) inhibitors for the treatment of immunological and neurodegenerative diseases. The partnership includes an upfront payment of $125 million to Rigel (RIGL) and possible development, regulatory and sales milestone payments of up to $835 million from Lilly. Rigel is also entitled to royalty payments varying from mid single digits to high teens dependent on its investment in clinical development. As part of the collaboration, Rigel expects to start Phase 2 clinical trials in 2021 for RIPK1 inhibitor R552.