CTI BioPharma Corp. (CTI or the Company) (NASDAQ and MTA: CTIC) announced today that it has completed recruitment in the PERSIST-1 pivotal Phase 3 clinical trial of pacritinib, a novel oral JAK2/FLT3 inhibitor that is being evaluated for the treatment of myelofibrosis. Under the development and commercialization agreement for pacritinib with Baxter International, Inc. (Baxter), CTI expects to receive a $20 million development milestone payment in connection with the first treatment dosing of the last patient enrolled in PERSIST-1. CTI expects to achieve this milestone and receive payment by mid-third quarter 2014.
"The PERSIST-1 clinical trial evaluating pacritinib, a novel JAK2/FLT3 inhibitor, is the most inclusive study of myelofibrosis patients seen in routine clinical practice to date," said Claire Harrison, M.D., Consultant Hematologist, Guy's and St. Thomas' NHS Foundation Trust, Guy's Hospital, London, United Kingdom and one of the principal investigators for PERSIST-1. "Previous randomized clinical trials have excluded patients with low platelet counts (below 50,000-100,000 per microliter (uL)) despite almost 30 percent of all myelofibrosis patients having disease-related thrombocytopenia. Currently available JAK1/JAK2 inhibitors are associated with treatment-emergent myelosuppression, including thrombocytopenia as a side effect of their therapy requiring reduced doses and sometimes early cessation of treatment when used in patients with disease-related thrombocytopenia. These patients represent an unmet medical need; a non-myelosuppressive JAK2 inhibitor would represent a significant advancement in the treatment of this chronic disease."
The PERSIST-1 trial is the first of two Phase 3 trials in the pacritinib development program in myelofibrosis. The second Phase 3 trial, PERSIST-2, is currently evaluating pacritinib for the treatment of patients with low platelet counts compared to best available therapy, including approved JAK2 inhibitors at their recommended dose and schedule for myelofibrosis patients with thrombocytopenia. The two clinical trials are intended to support an anticipated New Drug Application (NDA) regulatory submission in the U.S. in late 2015, followed by an anticipated Marketing Authorization Application (MAA) in Europe in 2016.
"Completing recruitment in the PERSIST-1 trial is a significant milestone in our development program for pacritinib, and we look forward to reporting top-line results in early 2015," said James A. Bianco, M.D., President and CEO of CTI BioPharma. "The high physician and patient interest in participating in this trial underscores the need for new, effective and less toxic treatment options for patients with myelofibrosis."
The PERSIST-1 trial was designed to enroll approximately 320 patients and is a randomized, open-label, multicenter trial comparing the efficacy and safety of pacritinib with that of best available therapy, other than JAK inhibitors, in patients with primary myelofibrosis, post-polycythemia vera myelofibrosis or post-essential thrombocythemia myelofibrosis, without exclusion for low platelet counts. The primary endpoint is the percentage of patients achieving a greater than or equal to 35 percent reduction in spleen volume measured by MRI or CT at 24 weeks of treatment.
Pacritinib Development Program in Myelofibrosis
Based on pacritinib's efficacy and tolerability profile demonstrated to date, CTI is pursuing a broad approach to advancing this therapy for myelofibrosis patients by conducting two Phase 3 clinical trials: one in a broad set of patients without limitations on blood platelet counts, the ongoing PERSIST-1 trial, and the other in patients with low platelet counts, the PERSIST-2 trial.
In March 2014, CTI announced the initiation of the PERSIST-2 trial, which will evaluate pacritinib in patients with myelofibrosis whose platelet counts are less than or equal to 100,000/uL. The trial is designed to enroll up to 300 patients in North America, Europe, Australia, New Zealand and Russia. In October 2013, CTI reached agreement with the U.S. Food and Drug Administration (FDA) on a Special Protocol Assessment for the PERSIST-2 trial, which is a written agreement between CTI and the FDA regarding the planned design, endpoints and statistical analysis approach of the trial to be used in support of a potential NDA submission.