In October 2018, Rigel entered into an exclusive license and supply agreement with Kissei to develop and commercialize fostamatinib disodium hexahydrate (fostamatinib) in all current and potential indications in Japan, China, Taiwan and the Republic of Korea

Fostamatinib is commercially available in the U.S. under the brand name TAVALISSE® and is the first and only spleen tyrosine kinase (SYK) inhibitor indicated for the treatment of thrombocytopenia in adult patients with chronic immune thrombocytopenia (ITP) who have had an insufficient response to a previous treatment.

Rigel received an upfront cash payment and is eligible for development and commercial milestone payments. Rigel will also receive product transfer price payments based on tiered net sales for the exclusive supply of product. 

Development of fostamatinib in Japan:

  • As of April 2021, Kissei had completed enrollment of its ongoing Phase 3 clinical trial in Japanese patients. This trial is required for approval by the Pharmaceuticals and Medical Devices Agency (PMDA) in Japan
  • A new drug application is anticipated to be submitted to the PMDA in 2022