Ambit Expands Collaboration with Bristol-Myers Squibb Company, In-Licenses Kinase Inhibitor Program Targeting Solid Tumors.

SAN DIEGO -- Ambit Biosciences today announced that it has expanded its collaboration with Bristol-Myers Squibb Company (NYSE:BMY) for the discovery of kinase inhibitors. The five-year agreement provides Bristol-Myers Squibb with access to Ambit's proprietary kinase profiling technology, KinomeScan, to accelerate its internal drug discovery and development efforts. As part of the transaction, Bristol-Myers Squibb granted Ambit an exclusive license to develop product candidates from a solid tumor-directed preclinical kinase inhibitor program. In addition, Ambit will receive an upfront payment, an equity investment and profiling revenues over the five-year term.

In January 2005, Ambit and Bristol-Myers Squibb entered into a drug screening collaboration in which Bristol-Myers Squibb used Ambit's KinomeScan platform to characterize the specificity of certain Bristol-Myers Squibb compounds. Under the expanded collaboration, Bristol-Myers Squibb will use Ambit's proprietary technology to rapidly identify, characterize and quantify kinase-small molecule interactions. Ambit will also conduct preclinical and clinical development of compounds under an exclusive license to one of Bristol-Myers Squibb's preclinical kinase inhibitor programs, which may result in development-based milestone payments and royalties should the compound receive regulatory approval for commercialization.

"In-licensing this preclinical kinase inhibitor program from Bristol-Myers Squibb complements Ambit's own internal pipeline of kinase inhibitors for the treatment of cancer," said Scott Salka, CEO of Ambit. "Ambit's kinase profiling technology, KinomeScan, creates significant value by enhancing and expediting the drug discovery and development process, from library and early discovery screening through preclinical and clinical development. The unique ability of KinomeScan to rapidly characterize entire libraries of compounds across a panel of well over 200 kinases makes the power of chemogenomics a reality and provides broad insight that cannot be obtained from profiling individual compounds or libraries using conventional enzyme activity assays."

About Ambit Biosciences

Ambit Biosciences is a privately-held biopharmaceutical company engaged in the discovery and development of small molecule kinase inhibitors for the treatment of cancer. Ambit plans to initiate clinical trials for oncology in 2006. Ambit's proprietary kinase screening technology, designed to expedite the drug discovery and development process, has been validated through collaborations with Roche, Bristol-Myers Squibb Company, GlaxoSmithKline, Pfizer and others. Ambit has raised a total of more than $50 million from investors including Perseus-Soros Biopharmaceutical Fund, Forward Ventures, Roche Venture Fund, Avalon Ventures, GIMV NV, MDS Capital and Genechem.