Ambit Biosciences Announces Second Expansion of Collaboration with Bristol-Myers Squibb.

SAN DIEGO -- Ambit Biosciences today announced a second expansion of its collaboration with Bristol-Myers Squibb Company (NYSE:BMY) for the discovery and development of novel kinase inhibitors. As part of this expansion, Ambit will screen Bristol-Myers Squibb's kinase-focused library using Ambit's proprietary KinomeScan[TM] technology.

KinomeScan is an innovative, high-throughput method for screening small molecule libraries against a large number of human kinases. At 353 human kinases, Ambit's largest panel, KinoMAX[TM], is the world's most comprehensive kinase profiling panel. Ambit and Bristol-Myers Squibb began their first KinomeScan collaboration in 2004.

"We are very pleased with Bristol-Myers Squibb's continued adoption of our KinomeScan technology for their kinase discovery efforts. This next step in our relationship joins Bristol-Myers Squibb's premier chemistry with Ambit's unparalleled kinase screening and discovery technology to accelerate the advancement of high quality drug candidates into clinical development," said Scott Salka, Chief Executive Officer of Ambit. "The unprecedented scale of this library screening project provides us with yet another opportunity to showcase the unique attributes of KinomeScan: panel size, screening throughput, data quality, turnaround time and cost efficiency."

Under the terms of the agreement, Bristol Myers-Squibb will make an undisclosed up-front cash payment to Ambit. In addition, Ambit will receive rights to certain preclinical and clinical compounds of Bristol-Myers Squibb.

About KinomeScan[TM]

KinomeScan is an innovative, high-throughput system for screening small molecule libraries against a large number of human kinases. KinomeScan employs proprietary active-site dependent competition binding assays to determine how compounds bind to both intended and unintended kinases. In addition to helping keep discovery programs on target, KinomeScan screens can opportunistically identify unanticipated interactions that can expand the therapeutic utility of compounds or serve as advanced starting points for new programs. Ambit's largest panel, KinoMAX, with 353 assays, is the world's most comprehensive kinase profiling panel.

Ambit's KinomeScan Division provides custom kinase profiling services to drug companies in addition to supporting the company's separate, internal drug development programs. KinomeScan is a key component of Ambit's partnerships with Roche, Bristol-Myers Squibb, GlaxoSmithKline, Cephalon, and others. The technology has been featured in papers published in Nature Biotechnology and The Proceedings of the National Academy of Sciences of the United States of America.

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. The company also markets the industry's most comprehensive kinase profiling service through its KinomeScan Division. KinomeScan is a proprietary technology designed to screen small molecule libraries against a large number of human kinases. Ambit has multiple drug candidates in pre-clinical and clinical development, including AC220, a selective class III receptor tyrosine kinase inhibitor currently in Phase I for treatment of acute myeloid leukemia. The company has partnerships with Roche, Bristol-Myers Squibb, GlaxoSmithKline, Cephalon, and other leading organizations. Ambit has a strong syndicate of investors including Perseus-Soros Biopharmaceutical Fund, Forward Ventures, Avalon Ventures, Genechem, Jov-CMDF, GIMV NV, Roche Venture Fund, and Bristol-Myers Squibb. For more information, please visit www.ambitbio.com.