SEATTLE, Jan. 9, 2013 /PRNewswire/ -- Cell Therapeutics, Inc. (CTI) (Nasdaq and MTA: CTIC) today announced that the Company has initiated clinical trial sites and began enrolling patients in a Phase 3 clinical trial, known as PERSIST-1 or PAC325, for pacritinib, CTI's investigational JAK2 inhibitor, which is being evaluated for the treatment of patients with myelofibrosis. The randomized trial is expected to enroll 270 patients and will evaluate the safety and efficacy of pacritinib compared to best available therapy, excluding JAK inhibitors, in patients with myelofibrosis. Pacritinib is a selective oral JAK2 inhibitor that demonstrated meaningful clinical benefits and good tolerability in myelofibrosis patients in Phase 2 clinical trials, without apparent drug-related thrombocytopenia or anemia. Myelofibrosis patients will be enrolled in the PERSIST-1 trial without exclusion for low platelet counts. Principal Investigators for the trial are Ruben A. Mesa, M.D., Deputy Director, Mayo Clinic Cancer Center and Chair, Hematology and Medical Oncology, Mayo Clinic in Arizona, and Claire Harrison, M.D., Consultant Hematologist, Guy's and St. Thomas' NHS Foundation Trust, Guy's Hospital, London, United Kingdom. "Current treatment of myelofibrosis by targeting JAK2 inhibition has been shown to be effective in managing the debilitating symptoms that are associated with this disease, although thrombocytopenia and anemia continue to be a challenge in managing this disease," said Steven E. Benner, M.D., Chief Medical Officer of CTI. "Data from earlier studies of pacritinib showed a clinically meaningful improvement in symptoms without suppression of platelets or red blood cells. We believe that pacritinib has the potential to offer an effective and well-tolerated treatment option for myelofibrosis patients, and are pleased to be initiating the Phase 3 PERSIST-1 clinical trial." Myelofibrosis is classified as a myeloproliferative neoplasm and is a chronic bone marrow disorder. Myelofibrosis is caused by the accumulation of malignant bone marrow cells that triggers an inflammatory response, scarring the bone marrow and limiting its ability to produce red blood cells prompting the spleen and liver to take over this function. Symptoms that arise from this disease include enlargement of the spleen, anemia, extreme fatigue and pain. It is estimated that the prevalence of myelofibrosis is approximately 30,000 in the United States. 1About PERSIST-1 PERSIST-1 is a multicenter, randomized, controlled Phase 3 trial comparing the efficacy and safety of pacritinib with that of best available therapy in patients with primary myelofibrosis, post-polycythemia vera myelofibrosis or post-essential thrombocythemia myelofibrosis. A total of 270 eligible patients will be randomized 2:1 to receive either pacritinib 400 mg taken orally, once daily or the best available therapy. Best available therapy includes any physician-selected treatment with the exclusion of JAK inhibitors. There will be no exclusion by patient platelet count. The primary endpoint will be the percentage of patients achieving a ≥ 35% reduction in spleen volume measured by MRI or CT at 24 weeks of treatment. The trial is expected to enroll patients at clinical sites in Europe, Australia and the United States. Additional PERSIST-1 (A Randomized Controlled Phase 3 Study of Oral Pacritinib v ERsus Be St Available Therapy in Pat Ient S with Primary Myelofibrosis, Post-Polycythemia Vera Myelofibrosis, or Post Essential Thrombocythemia Myelofibrosis) study details will be available at www.clinicaltrials.gov. PERSIST-1 is the first of two planned Phase 3 clinical trials in patients with myelofibrosis. The second Phase 3 clinical trial is planned to evaluate pacritinib compared to best available therapy, including JAK inhibitors, in patients with myelofibrosis whose platelet counts are <100,000 / µL.