ArQule to Introduce Novel FGFR Inhibitor Program Discovered Through Its Proprietary Kinase Inhibitor Platform at AACR-NCI-EORTC Conference.

WOBURN, Mass. -- ArQule, Inc. (Nasdaq: ARQL) today announced that a presentation at the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics in Boston on November 16, 2009, will highlight the discovery of potent, small molecule inhibitors of fibroblast growth factor receptor (FGFR) through the application of its proprietary ArQule Kinase Inhibitor Platform (AKIP[TM]).

"We have been successful in discovering non-ATP (adenosine triphosphate)-competitive inhibitors for a number of kinase targets," said Dr. Thomas C.K. Chan, chief scientific officer of ArQule. "The discovery of these FGFR inhibitors represents further proof-of-principle for ArQule's structure-based kinase inhibitor design paradigm. FGFR has been a difficult target to drug historically, and its role in oncology and other diseases, which has been described in the scientific literature, suggests its promise as a focal point of therapeutic intervention.

"Because they were developed using AKIP, the mode of binding for compounds generated in our FGFR program is distinct from commonly described ATP-competitive inhibitors," said Dr. Chan. "We believe that inhibitors that do not compete with ATP for binding will confer a higher degree of selectivity for the target kinase, with fewer off-target side effects and greater potential for effective combination with other therapies."

ArQule's first collaboration utilizing AKIP platform capabilities, with Daiichi Sankyo Co., Ltd., was announced in November 2008. This collaboration is focused on discovering therapeutic compounds directed to two kinase targets in the field of oncology.

About ArQule

ArQule is a biotechnology company engaged in the research and development of next-generation, small-molecule cancer therapeutics. The Company's targeted, broad-spectrum products and research programs are focused on key biological processes that are central to cancer. ArQule's lead product, in Phase 2 clinical development, is ARQ 197, an inhibitor of the c-MET receptor tyrosine kinase. The Company has also initiated Phase 1 clinical testing with ARQ 621, designed to inhibit the Eg5 kinesin motor protein. An additional clinical-stage program includes compounds that activate the cell's DNA damage response mechanism mediated by the E2F-1 transcription factor. The Company's pre-clinical pipeline includes a compound designed to inhibit the BRAF kinase. ArQule's current discovery efforts, which are based on the ArQule Kinase Inhibitor Platform (AKIP[TM]) are focused on the identification of novel kinase inhibitors that are potent, selective and do not compete with ATP for binding to the kinase.

This press release contains forward-looking statements regarding the Company's ArQule Kinase Inhibitor Platform (AKIP[TM]) and its fibroblast growth factor receptor (FGFR) program that utilizes this technology. These statements are based on the Company's current beliefs and expectations, and are subject to risks and uncertainties that could cause actual results to differ materially. As we learn more about the technology, our current expectations may not be met. Positive information about discovery activities and pre-clinical studies does not ensure that clinical trials will be successful. For example, compounds discovered through AKIP technology may not demonstrate promising therapeutic effect; in addition, they may not demonstrate an appropriate safety profile in clinical trials as a result of known or as yet unanticipated side effects. Furthermore, the results achieved in pre-clinical and clinical trials may not be sufficient to meet applicable regulatory standards. Problems or delays may arise during pre-clinical development, clinical trials or in the course of developing, testing or manufacturing these compounds that could lead the Company to discontinue development. Even if later stage clinical trials are successful, the risk exists that unexpected concerns may arise from analysis of data or from additional data or that obstacles may arise or issues be identified in connection with review of clinical data with regulatory authorities or that regulatory authorities may disagree with the Company's view of the data or require additional data or information or additional studies. In addition, the planned timing of initiation and completion of clinical trials with compounds from the FGFR program are subject to the ability of the Company to enroll patients, enter into agreements with clinical trial sites and investigators, and other technical hurdles and issues that may not be resolved. Furthermore, ArQule may not have the financial or human resources to successfully pursue this or its other drug discovery programs in the future. Drug development involves a high degree of risk. Only a small number of research and development programs result in the commercialization of a product. For more detailed information on the risks and uncertainties associated with the Company's drug development and other activities see the Company's periodic reports filed with the Securities and Exchange Commission. The Company does not undertake any obligation to publicly update any forward-looking statements.