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Rain Therapeutics Garners Worldwide License to MDM2 Inhibitor Programs From Daiichi Sankyo

NEW YORK – Rain Therapeutics said on Wednesday that it has licensed worldwide rights to Daiichi Sankyo's investigational MDM2 inhibitor milademetan, which it will evaluate in solid and hematologic cancers with MDM2 amplification or overexpression.

The Newark, California-based biotechnology firm's global license extends to all indications under evaluation within the milademetan program, which the firm will rename RAIN-32. The financial terms of the deal were not disclosed.

Building on the research already conducted by Daiichi Sankyo, Rain will specifically focus on exploring the drug's activity in cancers characterized by MDM2 gene amplification or overexpression, starting with liposarcoma. Approximately two-thirds of liposarcoma patients have MDM2 amplification.

Milademetan is also being evaluated in combination with Daiichi Sankyo's investigational FLT3 inhibitor quizartinib in acute myeloid leukemia with FLT3 internal tandem duplication (ITD) mutations.

The US Food and Drug Administration and European regulators last year declined to approve quizartinib for relapsed or refractory FLT3-ITD AML based on data from the Quantum-R study, though Japanese regulators have approved the drug based on this data. Daiichi has said it is still committed to bringing the drug to market for this subset of AML patients, and is awaiting results from the Phase III Quantum-First study of quizartinib and chemotherapy in newly-diagnosed FLT3-ITD AML.

Meanwhile, in addition to being studied in combination with quizartinib in FLT3-ITD AML and MDM2-amplified liposarcoma, milademetan is being studied in various investigator-sponsored trials at MD Anderson Cancer Center and at the National Cancer Center Hospital in Tokyo. Studies have shown that continuous and intermittent dosing may improve tolerability of the agent compared to other MDM2 inhibitors.

"We hope to pursue a rapid registrational path for RAIN-32 in a challenging tumor type that lacks effective therapies, and look forward to rationally developing RAIN-32 for additional oncology indications where MDM2 activity plays a central role," Rain Cofounder Robert Doebele said in a statement.