ARQULE PROVIDES UPDATE ON CANCER PROGRAMS

ArQule has begun dosing in its Phase I clinical trial with ARQ 171, a second-generation compound generated through its Activated Checkpoint TherapySM (ACT) program. Phase I data on this compound, together with Phase II data from the ongoing ARQ 501 program, will form the basis of a future licensing decision by Roche. As previously communicated, Roche has an option to license ArQule's E2F-1 program in the field of cancer therapy.

The population in this open-label, dose-escalation trial will consist of patients with advanced solid tumors. The primary objective of the trial is to determine the safety, tolerability and maximum tolerated dose of ARQ 171. Secondary objectives are to determine the pharmacokinetic profile and to assess the preliminary anti-tumor activity of the compound.

"ARQ 171, which entered and completed GLP toxicology testing earlier this year, is the result of our biological insights into DNA damage response pathways and our capabilities in small-molecule chemistry and intelligent drug design," Stephen Hill, president and CEO of ArQule, said.

ArQule also updated progress in its other clinical programs. These include three Phase II trials with the first-generation E2F-1 compound, ARQ 501, as monotherapy in leiomyosarcoma and head and neck cancer and as combination therapy with gemcitabine in pancreatic cancer, as well as a Phase I trial with ARQ 197, a proprietary, orally administered small-molecule inhibitor of the c-Met receptor tyrosine kinase.

Patient recruitment is also continuing in the Phase 1 dose escalation trial with ARQ 197. Thirty-six patients have been treated with ARQ 197, at doses ranging from 20 to 360 mg per day. Based on current estimates, ArQule anticipates choosing a recommended Phase II dose for this compound by the end of the year and beginning initial Phase II exploration in early 2007.