SAN DIEGO, Dec. 12, 2011 /PRNewswire/ -- Pharmacyclics, Inc. (Nasdaq: PCYC), a biopharmaceutical company focused on developing and commercializing innovative small molecule drugs for the treatment of cancer and immune mediated diseases, announced today interim results from an ongoing Phase II trial of the selective irreversible Bruton's tyrosine kinase (BTK) inhibitor PCI-32765 in MCL. Dr. Michael Wang, Director of Mantle Cell Lymphoma Program at the University of Texas MD Anderson Cancer Center, presented these data at the ASH Annual Meeting in San Diego, CA. In this interim report, the investigational agent PCI-32765 demonstrated a high rate of overall response as a single therapy in patients with relapsed or refractory MCL, including patients that had been previously treated with the FDA-approved agent bortezomib (Velcade®). MCL is a B-cell lymphoma that is relatively rare, with about 16,000 people living with the disease in the U.S. This interim analysis included a total of 68 patients accrued to this Phase II trial. PCI-32765 was administered orally at 560 mg daily until disease progression. 51 patients (31 patients had bortezomib-naive disease, 20 patients had previously received bortezomib) had post-baseline tumor assessments and were thus evaluable for response. The ORR, according to the 2007 Non-Hodgkin's Lymphoma International Working Group criteria, was 69% (35/51 patients). ORR was similar in bortezomib-naive and bortezomib-exposed patients (71% and 65%, respectively). At the time of this analysis 31 of 35 (89%) responding patients have ongoing responses with the median follow-up of 3.7 months. Consistent with previous trials of PCI-32765, the most common adverse events reported in this trial were Grade 1 (mild) or 2 (moderate) fatigue, diarrhea and nausea. Three patients discontinued the study due to adverse events regardless of causality. Overall, these data support Phase III evaluation of PCI-32765 as a single agent in patients previously treated MCL.