CTI BioPharma Corp. (Nasdaq: CTIC) (“CTI” or “the Company”) today announced the outcome of a Type B, End-of-Phase-2a meeting with the U.S. Food and Drug Administration (“FDA” or “the Agency”) for the continued development of its investigational myelofibrosis treatment candidate, pacritinib. Following this meeting, CTI plans to evaluate 200 mg of pacritinib administered twice daily (BID) in 180 patients with myelofibrosis and severe thrombocytopenia. The Company plans to initiate the Phase 3 PACIFICA study in the third quarter of 2019.
“We are pleased to be able to move the pacritinib program forward and are now in the process of finalizing an amendment to the PAC203 protocol, which the FDA will review, to allow a transition to the new PACIFICA Phase 3 study, in which we plan to compare the 200 mg BID dose of pacritinib to Physician’s Choice in myelofibrosis patients with severe thrombocytopenia, an important unmet medical need,” said Adam R. Craig, M.D., Ph.D., President and Chief Executive Officer of CTI BioPharma. “We anticipate initiating the trial in the third quarter, which would put us on track for topline Phase 3 data in mid-2021.”
The randomized, open-label Phase 2 PAC203 dose-finding study was designed to evaluate the safety and efficacy of three dosing regimens of oral pacritinib in 150 patients with myelofibrosis. The Company expects topline safety and efficacy results from the Phase 2 portion of the PAC203 study in the third quarter of 2019 and is targeting presentation of the Phase 2 results at a scientific conference before the end of 2019.
The previous Phase 3 PERSIST program consisted of the PERSIST-1 trial, which was conducted in a broad set of patients without limitations on platelet counts, and the PERSIST-2 trial, which was conducted in patients with low platelet counts. An ad-hoc analysis of pooled data from PERSIST-1 and PERSIST-2 evaluated results from patients with platelet counts of less than 50,000 per microliter and showed that 23% (n=104) of patients administered pacritinib had a ≥35% spleen volume reduction (SVR), compared to 2% (n=48) (p=0.0007) given the best available therapy, which in the PERSIST-1 trial excluded JAK2 inhibitors and in the PERSIST-2 trial included the approved JAK2 inhibitor, ruxolitinib. The most common treatment-emergent adverse events of any grade occurring in 20% or more of patients treated with pacritinib within 24 weeks during the PERSIST-1 and PERSIST-2 trials were gastrointestinal (generally manageable diarrhea, nausea and vomiting) and hematologic (anemia and thrombocytopenia).
The Company is currently amending the protocol for the ongoing Phase 2 PAC203 study to include the new PACIFICA Phase 3 portion, in which CTI intends to compare the safety and efficacy of 200 mg of pacritinib administered twice daily to Physician’s Choice in 180 myelofibrosis patients with severe thrombocytopenia (platelet counts of less than 50,000 per microliter) at approximately 120 sites worldwide. Patients will be randomized in a ratio of 2:1 between pacritinib and Physician’s Choice. The primary endpoint of the trial is the percentage of patients who achieve at least 35% reduction in spleen volume at week 24. Dr. Srdam Verstovsek, Professor, Department of Leukemia, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, and Dr. John Mascarenhas, Associate Professor of Medicine Myeloproliferative Disorders Program, Tisch Cancer Institute, Mount Sinai School of Medicine, will be co-principal investigators in the PACIFICA study. In addition, Professor Claire Harrison, Professor of Medicine, Guy’s and St Thomas’ NHS Foundation Trust, London, will chair the study’s Steering Committee. – PR Newswire