ORGANIZATION AND NATURE OF OPERATIONS	12 Months Ended
Dec. 31, 2012
Organization and Nature Of Operations [Abstract]
ORGANIZATION AND NATURE OF OPERATIONS	1. ORGANIZATION AND NATURE OF OPERATIONS We are a clinical-stage biotechnology company organized as a Delaware corporation in 1993 engaged in the research and development of innovative cancer therapeutics. Our mission is to produce novel drugs with differentiated mechanisms of action that will extend the lives of our patients. These drugs target biological pathways implicated in a wide range of cancers. We employ technologies such as our ArQule Kinase Inhibitor Platform (“AKIP^TM”) to design and develop drugs that have the potential to fulfill this mission. Our lead product candidate is tivantinib (ARQ 197), an orally administered, small molecule inhibitor of the c-Met receptor tyrosine kinase (“c-MET”) and its biological pathway. C-MET is a promising target for cancer therapy, based on its multiple roles in cancerous cell proliferation, tumor spread, new blood vessel formation and resistance to certain drug therapies. We and our partners, Daiichi Sankyo Co., Ltd. (“Daiichi Sankyo”) and Kyowa Hakko Kirin Co., Ltd. (“Kyowa Hakko Kirin”), are implementing a clinical development program designed to realize the broad potential of tivantinib as a single agent and in combination with other anti-cancer therapies in a number of disease indications. Our strategy is to focus on the most promising indications within our clinical programs based upon continually generated and updated data. Our most advanced indication is liver cancer (“hepatocellular carcinoma” or “HCC”). We are also completing earlier-stage combination therapy trials with tivantinib and other anti-cancer agents that may provide data to support later-stage trials in additional indications. On January 31, 2013, we announced that the first patient had been enrolled in the pivotal Phase 3 METIV trial of tivantinib for patients diagnosed with HCC who have received one or two prior systemic anti-cancer therapies. The METIV trial is a randomized, double-blind, controlled study of previously treated patients with MET-high inoperable HCC who will receive tivantinib as a single agent or placebo. The primary endpoint of this trial is overall survival (“OS”), and the secondary endpoint is progression-free survival (“PFS”). Approximately 300 patients are planned to be enrolled at approximately 120 clinical sites worldwide. This trial is being conducted under a Special Protocol Assessment (“SPA”) agreement with the U.S. Food and Drug Administration (“FDA”). The METIV trial builds upon the results of a randomized, double-blind, placebo controlled, Phase 2 trial in HCC announced in January 2012 demonstrating that treatment with tivantinib as single agent therapy produced a statistically significant improvement in the primary endpoint of time-to-progression (“TTP”) in previously treated patients. Patients with higher levels of MET who were treated with tivantinib in this Phase 2 trial experienced pronounced benefit in prolonged TTP. Additional data from this trial, presented at the Annual Meeting of the American Society of Clinical Oncology (“ASCO”) in June 2012, demonstrated significant improvements in median overall survival (“OS”) and progression-free survival (“PFS”) in these MET-high patients. On January 11, 2013, we announced the top-line results of a randomized Phase 2 signal generation trial of tivantinib used in combination with irinotecan and cetuximab in patients with refractory or relapsed colorectal cancer (“CRC”). Although the trial did not meet its primary endpoint of PFS, the analysis of the patients enrolled (n=122) showed that median PFS was 8.3 months in the experimental arm (patients treated with irinotecan and cetuximab plus tivantinib), compared with 7.3 months in the control arm (patients treated with irinotecan and cetuximab plus placebo) (hazard ratio = 0.85, 95% CI: 0.55, 1.33). Objective Response Rate (“ORR”), a secondary endpoint, was 45 percent in the experimental arm versus 33 percent in the control arm but the difference was not statistically significant. The PFS results obtained in both the control arm and the experimental arm were longer than expected compared to previously published historical norms. Additional data and analyses from this trial are planned for presentation at a future medical meeting and will include mature OS data as well as analyses of patient sub-groups, biomarker status and regional variability, including pre- and post-study treatments. Adverse events were reported at similar rates in the experimental and control arms, except for increased neutropenia observed in the experimental arm, with no discontinuations of treatment for this reason. No treatment-emergent adverse events leading to death were assessed as related to study treatment. Tivantinib was generally well tolerated in combination with the doses of cetuximab and irinotecan studied in this trial. On October 2, 2012, we and Daiichi Sankyo announced that the independent Data Monitoring Committee (“DMC”) of the Phase 3 MARQUEE (Met inhibitor ARQ 197 plus Erlotinib vs. Erlotinib plus placebo in NSCLC) trial recommended the study be discontinued early following a planned interim analysis, when they concluded that the study would not meet its primary endpoint of improved OS. Although the interim analysis showed a statistically significant improvement in PFS in the intent-to-treat (ITT) population, this benefit did not carry over to OS. There were no safety concerns identified by the DMC to Daiichi Sankyo or ArQule during this interim analysis. MARQUEE is a randomized, double-blind, controlled pivotal trial conducted under an SPA to evaluate tivantinib in combination with erlotinib, an approved anti-cancer agent, in previously treated patients with locally advanced or metastatic, non-squamous NSCLC. We and Daiichi Sankyo have provided information regarding the study discontinuation to health authorities and those clinical investigators participating in studies of tivantinib. Data from this study will be presented at an upcoming peer review forum. Our analysis of these data will inform our decisions regarding potential further development in NSCLC or in certain biomarker-defined sub-groups within this disease population. In NSCLC, we are also conducting a Phase 2, randomized trial of tivantinib and erlotinib in patients with a mutated form of the KRAS gene. On October 30, 2012, we reported that we had been informed by Kyowa Hakko Kirin that it will permanently suspend enrollment in its ongoing Phase 3 ATTENTION (Asian Trial of Tivantinib plus Erlotinib for NSCLC without EGFR Mutation) trial following the recommendation of an independent Safety Review Committee (“SRC”) in Japan after the reporting of cases of interstitial lung disease (“ILD”) in the study as a drug-related adverse event. It is our understanding that patients who were enrolled in the ATTENTION trial at the time of the safety finding can continue to receive treatment with the combination of tivantinib and erlotinib upon request from the patient and investigator and after providing new informed consent. Data from the trial is expected in late 2013 or early 2014. The ATTENTION trial is investigating the use of tivantinib and erlotinib versus erlotinib and placebo in second line non-squamous non-small cell lung cancer (NSCLC). This trial is being conducted by Kyowa Hakko Kirin in Japan, South Korea and Taiwan. We have licensed commercial rights to tivantinib for human cancer indications to Daiichi Sankyo in the U.S., Europe, South America and the rest of the world, excluding Japan and certain other Asian countries, where we have licensed commercial rights to Kyowa Hakko Kirin. Our agreements with these partners provide for possible future milestone payments, royalties on product sales, and development funding, in addition to significant payments that we have already received. The most recent milestone payments under these agreements were made during 2011, when , we received $25 million from Daiichi Sankyo resulting from the dosing of the first patient in the MARQUEE trial and $10 million from Kyowa Hakko Kirin resulting from dosing of the first patient in the ATTENTION trial. The terms of our tivantinib licensing agreements with Daiichi Sankyo and Kyowa Hakko Kirin remain in effect following the recent developments in both of these trials. On November 10, 2011, we and Daiichi Sankyo announced the execution of a license agreement for the development of a new AKT inhibitor, ARQ 092, the first compound to emerge from the companies’ AKIP^TM collaboration. The license agreement provides exclusive rights to Daiichi Sankyo for the development, manufacturing and marketing of ARQ 092 on a worldwide basis. Under this agreement, we received a $10 million upfront fee from Daiichi Sankyo in November 2011. Our proprietary pipeline is directed toward molecular targets and biological processes with demonstrated roles in the development of human cancers. The most advanced candidates in this pipeline are ARQ 087, an inhibitor of fibroblast growth factor receptor, ARQ 621, an inhibitor of the Eg5 kinesin motor protein, and ARQ 736, an inhibitor of the RAF kinases, all of which are in Phase 1 clinical testing.

ORGANIZATION AND NATURE OF OPERATIONS

12 Months Ended

Dec. 31, 2012

Organization and Nature Of Operations [Abstract]

1. ORGANIZATION AND NATURE OF OPERATIONS

We are a clinical-stage biotechnology company organized as a Delaware corporation in 1993 engaged in the research and development of innovative cancer therapeutics. Our mission is to produce novel drugs with differentiated mechanisms of action that will extend the lives of our patients. These drugs target biological pathways implicated in a wide range of cancers. We employ technologies such as our ArQule Kinase Inhibitor Platform (“AKIP^TM”) to design and develop drugs that have the potential to fulfill this mission.

Our lead product candidate is tivantinib (ARQ 197), an orally administered, small molecule inhibitor of the c-Met receptor tyrosine kinase (“c-MET”) and its biological pathway. C-MET is a promising target for cancer therapy, based on its multiple roles in cancerous cell proliferation, tumor spread, new blood vessel formation and resistance to certain drug therapies. We and our partners, Daiichi Sankyo Co., Ltd. (“Daiichi Sankyo”) and Kyowa Hakko Kirin Co., Ltd. (“Kyowa Hakko Kirin”), are implementing a clinical development program designed to realize the broad potential of tivantinib as a single agent and in combination with other anti-cancer therapies in a number of disease indications. Our strategy is to focus on the most promising indications within our clinical programs based upon continually generated and updated data. Our most advanced indication is liver cancer (“hepatocellular carcinoma” or “HCC”). We are also completing earlier-stage combination therapy trials with tivantinib and other anti-cancer agents that may provide data to support later-stage trials in additional indications.

On January 31, 2013, we announced that the first patient had been enrolled in the pivotal Phase 3 METIV trial of tivantinib for patients diagnosed with HCC who have received one or two prior systemic anti-cancer therapies. The METIV trial is a randomized, double-blind, controlled study of previously treated patients with MET-high inoperable HCC who will receive tivantinib as a single agent or placebo. The primary endpoint of this trial is overall survival (“OS”), and the secondary endpoint is progression-free survival (“PFS”). Approximately 300 patients are planned to be enrolled at approximately 120 clinical sites worldwide. This trial is being conducted under a Special Protocol Assessment (“SPA”) agreement with the U.S. Food and Drug Administration (“FDA”). The METIV trial builds upon the results of a randomized, double-blind, placebo controlled, Phase 2 trial in HCC announced in January 2012 demonstrating that treatment with tivantinib as single agent therapy produced a statistically significant improvement in the primary endpoint of time-to-progression (“TTP”) in previously treated patients. Patients with higher levels of MET who were treated with tivantinib in this Phase 2 trial experienced pronounced benefit in prolonged TTP. Additional data from this trial, presented at the Annual Meeting of the American Society of Clinical Oncology (“ASCO”) in June 2012, demonstrated significant improvements in median overall survival (“OS”) and progression-free survival (“PFS”) in these MET-high patients.

On January 11, 2013, we announced the top-line results of a randomized Phase 2 signal generation trial of tivantinib used in combination with irinotecan and cetuximab in patients with refractory or relapsed colorectal cancer (“CRC”). Although the trial did not meet its primary endpoint of PFS, the analysis of the patients enrolled (n=122) showed that median PFS was 8.3 months in the experimental arm (patients treated with irinotecan and cetuximab plus tivantinib), compared with 7.3 months in the control arm (patients treated with irinotecan and cetuximab plus placebo) (hazard ratio = 0.85, 95% CI: 0.55, 1.33). Objective Response Rate (“ORR”), a secondary endpoint, was 45 percent in the experimental arm versus 33 percent in the control arm but the difference was not statistically significant. The PFS results obtained in both the control arm and the experimental arm were longer than expected compared to previously published historical norms. Additional data and analyses from this trial are planned for presentation at a future medical meeting and will include mature OS data as well as analyses of patient sub-groups, biomarker status and regional variability, including pre- and post-study treatments. Adverse events were reported at similar rates in the experimental and control arms, except for increased neutropenia observed in the experimental arm, with no discontinuations of treatment for this reason. No treatment-emergent adverse events leading to death were assessed as related to study treatment. Tivantinib was generally well tolerated in combination with the doses of cetuximab and irinotecan studied in this trial.

On October 2, 2012, we and Daiichi Sankyo announced that the independent Data Monitoring Committee (“DMC”) of the Phase 3 MARQUEE (Met inhibitor ARQ 197 plus Erlotinib vs. Erlotinib plus placebo in NSCLC) trial recommended the study be discontinued early following a planned interim analysis, when they concluded that the study would not meet its primary endpoint of improved OS. Although the interim analysis showed a statistically significant improvement in PFS in the intent-to-treat (ITT) population, this benefit did not carry over to OS. There were no safety concerns identified by the DMC to Daiichi Sankyo or ArQule during this interim analysis. MARQUEE is a randomized, double-blind, controlled pivotal trial conducted under an SPA to evaluate tivantinib in combination with erlotinib, an approved anti-cancer agent, in previously treated patients with locally advanced or metastatic, non-squamous NSCLC. We and Daiichi Sankyo have provided information regarding the study discontinuation to health authorities and those clinical investigators participating in studies of tivantinib. Data from this study will be presented at an upcoming peer review forum. Our analysis of these data will inform our decisions regarding potential further development in NSCLC or in certain biomarker-defined sub-groups within this disease population. In NSCLC, we are also conducting a Phase 2, randomized trial of tivantinib and erlotinib in patients with a mutated form of the KRAS gene.

On October 30, 2012, we reported that we had been informed by Kyowa Hakko Kirin that it will permanently suspend enrollment in its ongoing Phase 3 ATTENTION (Asian Trial of Tivantinib plus Erlotinib for NSCLC without EGFR Mutation) trial following the recommendation of an independent Safety Review Committee (“SRC”) in Japan after the reporting of cases of interstitial lung disease (“ILD”) in the study as a drug-related adverse event. It is our understanding that patients who were enrolled in the ATTENTION trial at the time of the safety finding can continue to receive treatment with the combination of tivantinib and erlotinib upon request from the patient and investigator and after providing new informed consent. Data from the trial is expected in late 2013 or early 2014. The ATTENTION trial is investigating the use of tivantinib and erlotinib versus erlotinib and placebo in second line non-squamous non-small cell lung cancer (NSCLC). This trial is being conducted by Kyowa Hakko Kirin in Japan, South Korea and Taiwan.

We have licensed commercial rights to tivantinib for human cancer indications to Daiichi Sankyo in the U.S., Europe, South America and the rest of the world, excluding Japan and certain other Asian countries, where we have licensed commercial rights to Kyowa Hakko Kirin. Our agreements with these partners provide for possible future milestone payments, royalties on product sales, and development funding, in addition to significant payments that we have already received. The most recent milestone payments under these agreements were made during 2011, when , we received $25 million from Daiichi Sankyo resulting from the dosing of the first patient in the MARQUEE trial and $10 million from Kyowa Hakko Kirin resulting from dosing of the first patient in the ATTENTION trial. The terms of our tivantinib licensing agreements with Daiichi Sankyo and Kyowa Hakko Kirin remain in effect following the recent developments in both of these trials.

On November 10, 2011, we and Daiichi Sankyo announced the execution of a license agreement for the development of a new AKT inhibitor, ARQ 092, the first compound to emerge from the companies’ AKIP^TM collaboration. The license agreement provides exclusive rights to Daiichi Sankyo for the development, manufacturing and marketing of ARQ 092 on a worldwide basis. Under this agreement, we received a $10 million upfront fee from Daiichi Sankyo in November 2011.

Our proprietary pipeline is directed toward molecular targets and biological processes with demonstrated roles in the development of human cancers. The most advanced candidates in this pipeline are ARQ 087, an inhibitor of fibroblast growth factor receptor, ARQ 621, an inhibitor of the Eg5 kinesin motor protein, and ARQ 736, an inhibitor of the RAF kinases, all of which are in Phase 1 clinical testing.