ArQule Provides Clinical Update on ARQ 197

Enrollment completed in Phase 2 trial in non-small cell lung cancer;

Enrollment begins in Phase 2 trial in hepatocellular carcinoma
WOBURN, Mass.--(Business Wire)--
ArQule, Inc. (Nasdaq: ARQL) today announced that patient enrollment in a Phase 2
trial with ARQ 197 in non-small cell lung cancer (NSCLC) has been completed.

Approximately 160 patients were enrolled in the NSCLC trial, which is a
randomized, double-blind trial comparing combination therapy with ARQ 197 and
erlotinib against erlotinib and placebo in EGFR (epidermal growth factor
receptor) inhibitor-naïve patients in second and third line settings, with the
primary endpoint being progression-free survival. Final data from this trial is
expected to be available in the first half of 2009.

The Company also announced that patient enrollment in a Phase 2 trial with ARQ
197 in hepatocellular carcinoma (HCC) has been initiated. The Phase 2 initiation
follows the successfully completed evaluation of patients enrolled in a safety
trial in this indication.

Approximately 100 patients with unresectable HCC who have failed one prior
systemic therapy are expected to be enrolled in the HCC trial, which is a
randomized, double-blind trial comparing patients treated with ARQ 197 to those
treated with placebo, with the primary endpoint being time-to-progression.

Separately and as part of the HCC tumor program, a Phase 1 safety trial in HCC
is being conducted with the combination therapy of ARQ 197 and sorafenib.

Additional trials with ARQ 197 are ongoing in MiT (Microphthalmia Transcription
Factor)-associated tumors and pancreatic cancer. Patients, physicians and other
healthcare professionals seeking additional information about these trials may
call 1-800-373-7827.

About ARQ 197 and Non-Small Cell Lung Cancer

Published scientific literature supports the role of c-Met in the onset of
resistance to EGFR therapy, and pre-clinical efficacy studies in NSCLC cells
conducted by ArQule have demonstrated synergy between ARQ 197 and erlotinib in
halting cancer cell proliferation.

According to the American Cancer Society, lung cancer (both small cell and
non-small cell) is the leading cause of cancer death for both men and women in
the U.S. About 85 percent to 90 percent of all lung cancers are of the non-small
cell type. In 2008, the American Cancer Society estimates that there will be
about 215,000 new cases of lung cancer in the U.S. and that 162,000 people will
die of this disease.

About ARQ 197 and HCC

Scientific literature related to HCC provides evidence of the aberrant
activation of the MET pathway. In addition, the dysregulation of c-Met and HGF
(hepatocyte growth factor) has been shown to be common in this disease. Cell
proliferation is a central mechanism responsible for liver cancer progression,
and c-Met is believed to play an important role in this process.

According to the National Cancer Institute, 21,370 new cases of HCC in the U.S.
were projected in 2008, and 18,410 deaths were projected to be caused by the
disease. In the U.S., the increasing incidence of HCC is related primarily to
hepatitis C infection and cirrhosis.

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. 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) are focused on the identification of novel kinase inhibitors that are
potent, selective and do not compete with ATP (adenosine triphosphate) for
binding to the kinase.

This press release contains forward-looking statements regarding the progress of
the Company`s clinical trials, including Phase 2 trials with ARQ 197.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.Positive information about early stage clinical trial results is not
necessarily indicative of clinical efficacy and does not ensure that later stage
or larger scale clinical trials will be successful. For example, ARQ 197 may not
demonstrate promising therapeutic effect; in addition, this compound may not
demonstrate an appropriate safety profile in further pre-clinical testing and in
current, later stage or larger scale clinical trials as a result of known or as
yet unanticipated side effects. The results achieved in later stage trials may
not be sufficient to meet applicable regulatory standards. Problems or delays
may arise during clinical trials or in the course of developing, testing or
manufacturing these compounds that could lead the Company or its partner 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, information or studies.In addition, the planned timing
of initiation and completion of clinical trials for ARQ 197 is 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.Drug development involves a high degree of risk. Only a small
number of research and development programs result in the commercialization of a
product. Furthermore, ArQule may not have the financial or human resources to
pursue drug discovery successfully in the future. 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.

ArQule, Inc.
William B. Boni, 781-994-0300
VP, Investor Relations/
Corp. Communications
www.ArQule.com

Copyright Business Wire 2009