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 Oncology, a clinical-stage biotech company focused on targeted therapies in oncology, who renamed the product RAIN-32.
  • In May 2023, Rain Oncology announced topline results from their Phase 3 MANTRA trial of milademetan for the treatment of dedifferentiated liposarcoma. The trial did not meet the primary endpoint of progression free survival vs. standard of care.