Safety of Pacritinib Versus Best Available Therapies in Patients with Myelofibrosis

Investigators, led by Naveen Pemmaraju, evaluated the toxicities and risk-adjusted safety of pacritinib, a novel JAK2/IRAK1 inhibitor, against best available therapies in patients with myelofibrosis. According to their poster, featured at the 2022 American Society of Clinical Oncology Annual Meeting, the safety profile of pacritinib was “comparable or superior” to best available therapies, including ruxolitinib.

Patients in the study were a treated with pacritinib 200 mg twice a day. The risk-adjusted rate of overall and fatal adverse events (AEs), bleeding AEs, cardiac AEs, major cardiac events (MACE), infections, thrombosis, and secondary malignancies.

The pacritinib group was comprised of 160 patients, and the best available therapy group had 98 patients, 44 of which were on ruxolitinib. Notably, the rate of AEs was higher for pacritinib compared to best available therapy, but the rate of fatal AEs was lower. Bleeding and cardiac AEs were slightly lower on pacritinib. The rate of malignant neoplasms was comparable between the groups, though non-melanoma skin cancers occurred less frequently with pacritinib.

Ultimately, the authors judged that pacritinib at 200 mg two times a day “may represent a full-dose therapeutic option for patients with myelofibrosis, including those with thrombocytopenia.”