Rigel has a long-standing collaboration with Daiichi-Sankyo (Daiichi) for developing murine double minute 2 (MDM2) protein inhibitors in cancer, which were discovered in Rigel’s laboratories.

Preliminary safety and efficacy data from an early Phase 1 study of milademetan (formerly DS-3032), an oral selective MDM2 inhibitor, in hematological malignancies suggests that it may be a promising potential treatment for oncology indications.

Rigel received an upfront payment and is eligible for milestone payments, as well as tiered royalty payments on any future net sales of any products emerging from the collaboration.

Development of milademetan:

  • In September 2020, worldwide rights were out-licensed from Daiichi-Sankyo to Rain Therapeutics, a privately held, clinical-stage biotech company focused on targeted therapies in oncology, who renamed the product RAIN-32
  • In April 2021, Rain announced a planned Phase 3 study for the asset in liposarcoma, a cancer that occurs in the body’s fat cells, to start in H2 2021