13 March 2018 - - Seattle,Washington-based blood-related cancers therapies specialist CTI BioPharma Corp. (NASDAQ/MTA: CTIC) has published results from the Phase 3 PERSIST-2 clinical trial of pacritinib, an investigational JAK2 inhibitor, online in JAMA Oncology, the company said.
The randomized, international, multicenter study compared the efficacy and safety of pacritinib at two dose levels, compared with best available therapy, which included ruxolitinib (a JAK1/JAK2 inhibitor), 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 at 24 weeks of treatment in 27 patients compared to 2 patients 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 in 37 patients, compared to 10 patients 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 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.
Bleeding events, most commonly epistaxis, were reported at similar rates in all arms.
Pacritinib is an investigational oral kinase inhibitor with specificity for JAK2, FLT3, IRAK1 and CSF1R. In addition to myelofibrosis, the kinase profile of pacritinib suggests its potential therapeutic utility in conditions such as acute myeloid leukemia, myelodysplastic syndrome, chronic myelomonocytic leukemia, and chronic lymphocytic leukemia, due to its inhibition of c-fms, IRAK1, JAK2 and FLT3.
CTI BioPharma is a biopharmaceutical company focused on the acquisition, development and commercialization of novel targeted therapies covering a spectrum of blood-related cancers. The company has a late-stage development pipeline, including pacritinib for the treatment of patients with myelofibrosis.