On December 3, 2018 ArQule, Inc. (Nasdaq: ARQL) reported its presented preliminary results from the Company’s Phase 1 dose escalation study for ARQ 531, an orally bioavailable, potent and reversible inhibitor of both wild type and C481S-mutant Bruton’s tyrosine kinase (BTK) in patients with relapsed or refractory hematologic malignancies at the 2018 American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting in San Diego (Press release, ArQule, DEC 3, 2018, View Source [SID1234531820]).

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Dr. Brian Schwartz, Chief Medical Officer of ArQule commented, "We are encouraged by the pace at which this trial is progressing and by the level of target engagement we are observing as we continue to dose escalate. Four out of the five heavily pretreated CLL patients enrolled in the last two cohorts with the BTK-C481S mutation have experienced tumor shrinkage."

"These data provide further evidence of ARQ 531’s potential to become a new therapeutic option for patients with B cell malignancies," commented Paolo Pucci, Chief Executive Officer of ArQule. "There is significant unmet need for patients with relapsed or refractory B-cell malignancies in particular those with the C481S-mediated resistance to irreversible BTK inhibitors such as ibrutinib."

The reported data are from the ongoing Phase 1, open label, single arm dose escalation 3+3 study and include the first six cohorts (n=20) at dose levels of 5, 10, 15, 20, 30 and 45 mg once a day in patients with relapsed or refractory chronic lymphocytic leukemia (CLL), small lymphocytic leukemia (SLL), Waldenstrom’s macroglobinemia and B-cell Non-Hodgkin lymphomas.

Key findings presented include the following:

ARQ 531 has demonstrated a manageable safety profile with no dose-limiting toxicities observed to date
Pharmacokinetic data are nearly dose proportional with a mean plasma half-life that supports QD dosing
Pharmacodynamic biomarkers for cohorts 4 through 6 showed profound pBTK inhibition
Anti-tumor activity, with reduction of tumor burden, was observed in 9 out of 20 patients
At the first assessment of tumor response, 80% of the ibrutinib refractory, heavily pretreated CLL patients (4 out of 5) in the highest dose cohorts (30 and 45 mg) experienced tumor shrinkages
Four out of 5 lymphoma patients derived benefit with shrinkages between 27 and 58%, including 1 PR in a Follicular Lymphoma patient who began at 5 mg, was dose escalated to 15 and then 45 mg, and remains on therapy after 70 weeks
The study is on-going and dose escalation continues
The presented poster, A Phase 1 Dose Escalation Study of ARQ 531 in Selected Patients with Relapsed or Refractory Hematologic Malignancies, is available on the company’s website at View Source

The Company will hold a conference call and webcast today at 9:00 a.m. ET to discuss these results. The live webcast can be accessed in the "Investors and Media" section of our website, www.arqule.com, under "Events & Presentations." You may also listen to the call by dialing (877) 868-1831 within the U.S. or (914) 495-8595 outside the U.S. A replay will be available two hours after the completion of the call and can be accessed in the "Investors & Media" section of our website, www.arqule.com, under "Events and Presentations."

About BTK and ARQ 531

Bruton’s tyrosine kinase, BTK, is a therapeutic target that has been clinically proven to inhibit B-cell receptor signaling in blood cancers. ARQ 531 is an orally bioavailable, potent and reversible BTK inhibitor. Biochemical and cellular studies have shown that ARQ 531 inhibits both the wild type and C481S-mutant forms of BTK. The C481S-mutation is a known resistance mechanism for first generation irreversible BTK inhibitors. In preclinical studies, ARQ 531 has demonstrated good oral bioavailability as well as favorable pharmacokinetic, pharmacodynamic and metabolic properties.