Results of ibrutinib Phase 2 study in patients with mantle cell lymphoma published in NEJM

Jun 20 2013

Pharmacyclics, Inc. (the "Company") (Nasdaq: PCYC) today announced that The New England Journal of Medicine (NEJM) published results of a Phase 2 study evaluating the investigational oral Bruton's tyrosine kinase (BTK) inhibitor ibrutinib in patients with relapsed/refractory mantle cell lymphoma (MCL) online. These data suggested ibrutinib may be effective and generally well-tolerated in patients with relapsed/refractory MCL.

Results of a separate study examining the safety and efficacy of ibrutinib monotherapy for the treatment of patients with relapsed/refractory chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL), some of whom had deletion of part of chromosome 17 (del 17p), has also been published online by The NEJM. Pharmacyclics sponsored both studies and is jointly developing ibrutinib with Janssen Research & Development, LLC.

"There remains a significant unmet need for patients with MCL," said lead author Michael Wang, M.D., Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center. "These data are exciting because they demonstrate that the longer MCL patients are treated with ibrutinib the better they respond to the treatment."

The study evaluated 111 patients with relapsed/refractory MCL treated with ibrutinib. The majority of patients (86 percent) had intermediate or high-risk MCL and had previously undergone treatment with a median of three prior therapies before enrollment in the study. Patients were enrolled in two cohorts based on whether they had prior exposure to bortezomib. Overall response rate across both cohorts was 68 percent with 47 percent of patients achieving a partial response and 21 percent achieving a complete response where all signs of cancer are gone. The estimated median response duration was 17.5 months. The median progression free survival was 13.9 months and while the median overall survival for this study has not yet been reached it is estimated to be 58 percent at 18 months. The overall response to ibrutinib was independent of prior treatment including bortezomib and lenalidomide or underlying risk/prognosis, bulky disease, gender or age. In an initial subset of patients enrolled in the study who have the longest follow up>

The majority of adverse events (AEs) were Grade 1 or 2 in severity, with the most common AEs attributed to ibrutinib being diarrhea, infections and fatigue. Only 7 percent of patients irrespective of relationship experienced an AE leading to treatment discontinuation. Grade 3-4 hematological toxicities were infrequent, with neutropenia (16 percent), thrombocytopenia (11 percent) and anemia (10 percent) as the most frequent hematological AEs reported.

Data from this study were presented at the annual meeting of the American Society of Hematology in December 2012, the European Hematology Association annual meeting in June 2013 and are being presented at the 12th International Conference on Malignant Lymphoma in Lugano, Switzerland this week.