SEATTLE, Sept. 24, 2012 /PRNewswire/ -- Cell Therapeutics, Inc. ("CTI") (Nasdaq and MTA: CTIC) announced today that the phase 1 study data of its highly selective oral JAK2 inhibitor pacritinib, or SB1518, showed encouraging anti-tumor activity and good tolerability in 34 patients with relapsed/refractory lymphoma. The results were published online in the Journal of Clinical Oncology in September, 2012. Thirty-four patients received daily oral doses of pacritinib ranging from 100mg to 600mg. The maximal tolerated dose was not reached. Median time on study was 88 days (range of one to 574 days) with six patients on pacritinib for longer than six months. Seventeen of the 34 patients (50%) had measurable decreases in target tumor measurements ranging from 4% to 70% shrinkage. Partial remissions were noted in three patients (mantle cell (2), indolent lymphoma (1)) while 15 patients had stable disease. Median progression free and overall survival was 120 and 130 days, respectively. Gastrointestinal (GI) side effects were most frequent and mild to moderate (grade 1-2) with no patient reporting severe (grade 3-4) GI side effects even at the 600mg dose level. Cytopenias were infrequent and modest (less than 15% all grades). "While it is becoming increasingly accepted that activating mutations in JAK2 and FLT3 play an important role in a majority of patients with acute myeloid leukemia, this phase 1 study suggests the potential therapeutic value of targeting the JAK2 pathway in lymphomas with encouraging single agent activity demonstrated despite the extensive degree of prior therapy and refractory nature of the disease among the patients who were enrolled in this trial," noted Steven E. Benner, M.D., M.H.S., Chief Medical Officer of CTI. About the Phase 1 Study The primary objective was a dose finding, pharmacokinetic/pharmacodynamics study of oral pacritinib in patients with relapsed lymphoma.