NORTH CHICAGO, Ill., June 3, 2013 /PRNewswire/ -- AbbVie (NYSE: ABBV) today announced results from a Phase I study of ABT-199, an investigational BCL-2 (B-cell lymphoma 2) selective inhibitor, for the treatment of patients with relapsed/refractory chronic lymphocytic leukemia (CLL), the most common leukemia in the United States, and relapsed/refractory non-Hodgkin's lymphoma (NHL). Results from the study were presented at the 2013 Annual Meeting of the American Society of Clinical Oncology (ASCO). This Phase I, open-label, multicenter, international trial was designed to assess the safety, determine the maximum tolerated dose and recommended Phase II dose, and evaluate the pharmacokinetics of ABT-199 in patients with relapsed/refractory CLL and NHL. Secondary objectives included preliminary efficacy, including objective response rate (ORR), duration of response, time to progression, progression-free survival (PFS) and overall survival (OS). "The ABT-199 data underscore AbbVie's commitment to the development of treatments for some of the hardest-to-treat cancers like CLL and NHL," said Gary Gordon, M.D., divisional vice president, oncology clinical development, AbbVie. "Early trials of ABT-199 have shown the compound's potential in these hematological malignancies, which support the continuation of its clinical development program." CLL ArmAs of April 2013, 56 patients have enrolled in the CLL arm of the Phase I trial, and 40 patients are currently active. Study participants were given a single oral dose of ABT-199, followed by six days without medication, before continuous once-daily dosing. Due to concerns over tumor lysis syndrome (TLS), the initial dose was reduced and daily dosing was modified. Single-agent activity was observed in the trial and warrants further single-agent and combination trials evaluating ABT-199 in patients with CLL. Dose and schedule evaluation will continue. "While still early in the development process, the activity with ABT-199 as a single-agent supports further investigation of the compound in patients with CLL, a patient population with a high unmet need for new treatment options," said Matthew Davids, M.D., attending physician in the Lymphoma Program of the Division of Hematologic Malignancies at Dana-Farber Cancer Institute, and Instructor in Medicine at Harvard Medical School. During the study, 13 patients discontinued treatment; seven due to progression of disease and six for other reasons (two due to TLS, two for other illnesses, one for thromboembolic event and one consent withdrawal). The most common non-hematological adverse events (AEs) during the study were nausea (36%), diarrhea (30%), fatigue (25%), upper respiratory tract infection (23%) and cough (16%). In the first study group, TLS occurred in all three of the enrolled patients; once the modified dosing schedule was utilized, three of the 53 patients experienced adverse events of TLS. One fatal adverse event occurred in a patient with laboratory evidence of TLS.