Deal includes Phase II candidate and R&D on additional compounds in various indications.

Ambit Biosciences is receiving an up-front payment of $40 million as part of its agreement with Astellas Pharma related to FLT3 kinase inhibitors in oncology and nononcology indications. Precommercialization milestone fees under the worldwide development and commercialization deal could reach $350 million.

The partnership covers AC220, Ambit’s lead drug, which is in a Phase II trial covering relapsed/refractory acute myeloid leukemia (AML) patients.  The companies will collaborate to develop the compound for AML as well as other indications. They will also conduct R&D on additional FLT3 inhibitors.

The firms will share equally in the responsibilities and expenses of developing all products in the U.S. and Europe. Astellas has sole responsibility to fund development in all other territories.

Astellas will handle commercialization of all products, including funding. Ambit will be entitled to postapproval milestone payments upon the achievement of certain sales thresholds as well as tiered double-digit royalties on net sales. In the U.S. Ambit will also have the option to co-promote AC220 and other products. If exercised, Astellas and Ambit will share equally in profits and losses generated from U.S. sales.

AC220 is an orally available, potent, and highly selective small molecule that was designed as a second-generation FMS-like tyrosine kinase-3 inhibitor using Ambit’s discovery engine, KINOMEscan™.

The Phase II trial is designed to support potential registration of AC220 as monotherapy treatment in adult and elderly patients with relapsed/refractory AML that have the internal tandem duplication mutation in the FLT3 kinase. The FLT3 kinase is mutated and constitutively activated in 25–40% of such patients, according to Ambit.

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