Phase III PERSIST-2 trial of SB 1518 in myelofibrosis published in JAMA Oncology.- CTI BioPharma Corp.

CTI BioPharma Corp announced that results from the Phase III PERSIST-2 clinical trial of SB 1518 (pacritinib) have been published online in JAMA Oncology. The randomized, international, multicenter study compared the efficacy and safety of pacritinib at two dose levels, compared with best available therapy (BAT), which included ruxolitinib, in patients with myelofibrosis and thrombocytopenia (defined as platelet counts ?100 x 109/L).

In the intent-to-treat patient population of the study, the combined pacritinib arms (400mg once daily and 200mg twice daily dosing, 149 patients total) demonstrated a significant improvement of 35% or more in spleen volume reduction (SVR) at 24 weeks of treatment in 27 patients (18%) compared to 2 patients (3%) out of 72 patients in the BAT arm, which included treatment with ruxolitinib (P=0.001). The combined pacritinib treatment arms also demonstrated a greater than 50% reduction in total symptom score (TSS) in 37 patients (25%), compared to 10 patients (14%) in the BAT arm (P=0.079).

Additionally, an exploratory analysis of the 74 patients who received pacritinib 200mg twice daily showed an improvement of 35% or more reduction of SVR in 16 patients (22%; P=0.001 vs BAT) and 50% or greater reduction of TSS in 24 patients (32%; P=0.01 vs BAT). Pacritinib was generally well tolerated. The most commonly reported (?15%) nonhematologic adverse events with pacritinib were gastrointestinal events, fatigue, peripheral edema, and dizziness, and those with BAT (including 19 patients with watchful-waiting only) were abdominal pain, fatigue, diarrhea, and peripheral edema.

See: "Pacritinib vs Best Available Therapy, Including Ruxolitinib, in Patients With Myelofibrosis - A Randomized Clinical Trial." John Mascarenhas et al. JAMA Oncol. Published online March 8, 2018. doi:10.1001/jamaoncol.2017.5818