Pacritinib Approved for Patients With Intermediate or High-Risk Myelofibrosis

The US Food and Drug Administration (FDA) has granted accelerated approval to pacritinib for the treatment of adult patients with intermediate or high-risk primary or secondary (occurring after polycythemia vera or essential thrombocythemia) myelofibrosis with platelet counts below 50 × 10⁹/L.

Pacritinib, an oral kinase inhibitor targeting JAK2 and IRAK1 without inhibiting JAK1, represents the first therapy approved specifically for patients with cytopenic myelofibrosis.

This decision is based on efficacy data from the phase III PERSIST-2 study. Patients with myelofibrosis were randomized 1:1:1 to receive either pacritinib 200 mg twice daily, pacritinib 400 mg once daily, or best available therapy. Among patients with baseline platelet counts below 50 × 10⁹/L who received pacritinib 200 mg, 29% experienced reductions in spleen volume of 35% or greater, compared with 3% of patients treated with best available therapy.

Adverse events (AEs) occurring in at least 20% of patients treated with pacritinib 200 mg twice daily included diarrhea, thrombocytopenia, nausea, anemia, and peripheral edema. Serious AEs reported in at least 3% of patients treated at this dose were anemia, thrombocytopenia, pneumonia, cardiac failure, disease progression, pyrexia, and squamous cell carcinoma of skin.

Source: CTI BioPharma press release, February 28, 2022.