The results were generated from 221 patients who reached the primary analysis time point of Week 24 at the time the clinical hold was imposed by the US Food and Drug Administration in February this year.
Preliminary results showed a statistically significant response rate as measured by minimum spleen volume reduction (SVR) of 35% compared to BAT, including ruxolitinib.
The other primary endpoint, at least a 50% reduction in Total Symptom Score (TSS) was not met.
CTI BioPharma plans to present additional data from ongoing analyses along with top-line results from PERSIST-2 at an upcoming scientific meeting.
Pacritinib is an oral tyrosine kinase inhibitor with activity against Janus Associated Kinase 2 (JAK2), FMS-like tyrosine kinase 3 (FLT3), IRAK1 and CSF1R. It is being developed and commercialized jointly by CTI BioPharma and Shire.
CTI BioPharma president and CEO James Bianco said: "Having analyzed data from two Phase 3 trials with the only JAK inhibitor to be studied in severely thrombocytopenic patients, including patients on JAK2 therapy or those who failed prior JAK2, we are encouraged by pacritinib's clinical profile in this difficult-to-treat group of patients with myelofibrosis.”
Under a global license deal, the companies will jointly commercialize pacritinib in the US, while Shire has exclusive commercialization rights for all indications outside the US.
Image: CTI BioPharma announces top-line results from PERSIST-2 phase 3 trial of pacritinib for high-risk patients with advanced myelofibrosis. Photo: courtesy of jk1991 at FreeDigitalPhotos.net.