New analysis of Phase III data on SB 1518 (pacritinib) shows benefits in myelofibrosis- CTI BioPharma/Baxalta

CTI BioPharma Corp and Baxalta have announced results from a new analysis of the pivotal Phase III trial, PERSIST-1, evaluating SB 1518 (pacritinib) versus best available therapy, excluding treatment with JAK2 inhibitors (BAT), in patients with myelofibrosis. Data examining patient outcomes across baseline demographic factors that are associated with prognosis � including age, baseline hemoglobin, baseline platelet count, ECOG status, JAK2 mutation status and red blood cell transfusion dependency � showed that treatment with pacritinib resulted in consistent rates of spleen volume reduction and control of disease-related symptoms across all intermediate or high-risk myelofibrosis subgroups.

Findings showed that results (from the primary analysis) were consistent across all subgroups evaluated. Achievement of 35 percent or greater spleen volume reduction was independent of most risk factors assessed and a 50 percent or more decrease in Total Symptom Score was independent of characteristics evaluated, except bone pain score greater than three at baseline. The most common adverse events in the pacritinib arm vs. BAT that showed more than 5 percent difference were diarrhea (57 percent vs. 12 percent), nausea (29 percent vs. 6 percent) and vomiting (19 percent vs. 5 percent). No Grade 4 gastrointestinal events were reported. These findings were presented at the 57th American Society of Hematology Annual Meeting.

Comment: Pacritinib may offer an advantage over other JAK inhibitors through effective treatment of symptoms while having less treatment-emergent thrombocytopenia and anemia than has been seen in currently approved and in-development JAK inhibitors.