US-based CTI BioPharma has reported positive results from a Phase II trial of pacritinib, a next-generation oral JAK2/FLT3 multikinase inhibitor, in patients with myelofibrosis.
The trial evaluated safety and efficacy of pacritinib in patients with myelofibrosis who had clinical splenomegaly poorly controlled with standard therapies or were newly diagnosed with intermediate or high-risk disease, and not considered candidates for standard therapy.
Pacritinib is undergoing Phase III development in the PERSIST programme, which is led by Moffitt Cancer Center clinical director of the Department of Malignant Hematology Dr Rami Komrokji.
Data from this trial showed that pacritinib is active in patients with myelofibrosis, resulting in spleen volume reduction, while showing improvement in disease-related symptoms without causing clinically significant myelosuppression, the company claimed.
According to the company, pacritinib was well tolerated, including in patients with disease-related anemia and thrombocytopenia, with the predominant side effect being manageable gastrointestinal toxicity.
CTI BioPharma president James Bianco said: "The results of this Phase II study are consistent with our recently reported top-line results from the PERSIST-1 randomised Phase III trial with a comparable reduction in spleen volume of up to week 24, in addition to the observation that patients on pacritinib continued to respond over time.
"Based on the results of this study and the recently announced PERSIST-1 top-line data, we believe pacritinib may provide an important therapeutic option for a broader spectrum of patients suffering from this challenging disease.
"We look forward to presenting additional data from PERSIST-1 at a scientific conference this year."
During the multicenter, single-arm, open-label Phase II trial, patients were allowed to enroll irrespective of their degree of thrombocytopenia, anemia or neutropenia.
A total of 35 patients with median age of 69 years were enrolled in the trial and treated with pacritinib 400mg administered once daily in 28-day cycles.
Dr Komrokji said: "The publication of the Phase II results in the Blood journal was timely as we recently learned about the positive results from PERSIST-1 randomised Phase III study.
"Currently, myelofibrosis patients with anemia and thrombocytopenia have limited treatment options for splenomegaly and constitutional symptoms and these data show that pacritinib has potential to help patients that are sub-optimally managed on currently available treatments."
The trial's endpoint was assessment of the spleen response rate, defined as the proportion of subjects achieving 35% or greater reduction in spleen volume from baseline up to week 24, as measured by magnetic resonance imaging (MRI).
Other endpoints of the trial included the proportion of patients with 50% or greater reduction in spleen size, as determined by physical exam and the proportion of patients with 50% or greater reduction in total symptom score (TSS), from baseline up to week 24.