Phase I study results of Pharmacyclics' PCI-32765 Btk inhibitor for B cell NHL presented at ASCO

Pharmacyclics, Inc. (Nasdaq: PCYC) today announced results from a Phase I study of its novel orally administered Bruton's tyrosine kinase (Btk) inhibitor, PCI-32765, in patients with relapsed or refractory B cell non-Hodgkin's lymphoma (NHL) including chronic lymphocytic leukemia (CLL) and Waldenstroms Macroglobulinemia (WM). These data are being presented at the American Society of Clinical Oncology (ASCO) Annual Meeting taking place this week in Chicago, IL.

This multicenter Phase I study is being conducted in collaboration with investigators at leading lymphoma centers including Stanford University, MD Anderson Cancer Center, the University of Chicago, the University of Vermont, and US Oncology group. The trial is an ongoing open-label, dose-escalation study of PCI-32765 in recurrent B cell malignancies treating a minimum of 6 patients per cohort. Five dose levels are being explored—1.25, 2.5, 5.0, 8.3 and 12.5 mg/kg/day. Each cycle of treatment consists of 28 consecutive days of once daily dosing followed by a 7-day rest period.  An additional dose group at 8.3 mg/kg/day is also being explored using a 35-day cycle with no rest period ("continuous dosing" or "CD"). Dose limiting toxicities were evaluated at the end of the first cycle and drug efficacy is evaluated every 2 cycles. Safety is being monitored throughout the trial.  Data, from the second cohort on, has demonstrated that PCI-32765 fully occupied the active site of the target enzyme Btk in peripheral blood cells with minimal variability, fully inhibited surrogate biomarkers for up to 24 hours, and was well tolerated by patients.