Pacritinib Superior to Best Available Therapy for Myelofibrosis Patients With Thrombocytopenia, Anemia

Full-dose pacritinib is efficacious in terms of spleen volume reduction, symptoms, and transfusion response in patients with myelofibrosis (MF) with thrombocytopenia and anemia, according to a recent study. The study was led by Pankit Vachhani, MD, of the O’Neal Comprehensive Cancer Center at the University of Alabama at Birmingham, and presented at the Twelfth Annual Meeting of the Society of Hematologic Oncology in Houston, Texas.

“Thrombocytopenia and anemia pose treatment challenges in myelofibrosis,” wrote Dr. Vachhani and colleagues. “When these two cytopenias co-occur (‘bicytopenia’), management becomes particularly challenging, and appropriate treatment selection is critical to optimize efficacy while minimizing myelosuppressive side effects.”

The researchers presented data from the PERSIST-2 trial on spleen and symptom benefit in patients with moderate or severe bicytopenia at baseline (platelet count <100 × 10⁹L and hemoglobin <10 g/dL) who were treated with pacritinib. Endpoints included spleen volume reduction (SVR) ≥35%, total symptom score (TSS) reduction of ≥50%, Patient Global Impression of Change (PGIC), and transfusion independence response (TI-R).

Forty-six patients received pacritinib 200 mg twice daily, whereas 47 received best available therapy (BAT). Pacritinib demonstrated superiority to BAT for all endpoints. Twenty percent of patients in the pacritinib group had SVR ≥35%, compared with 0% in the BAT group (P=0.0054). This trend was also observed with TSS: 32.5% of patients in the pacritinib group had ≥50% TSS reduction, compared with 10.5% of patients in the BAT group (P=0.0274). Thirty percent of patients on pacritinib had a PGIC response of “very much” or “much” improved at week 24, compared with 13.2% patients on BAT.

Twenty-seven patients on pacritinib and 36 on BAT received red blood cell transfusions at baseline. Of those patients, 26% on pacritinib and 8% on BAT achieved TI-R (P=0.0838).

“Pacritinib at full dose demonstrates efficacy for spleen, symptoms, and transfusion response in patients with myelofibrosis and both thrombocytopenia and anemia,” the researchers concluded.

Reference

Vachhani P, Gupta V, Palandri F, et al. Efficacy of pacritinib in patients with myelofibrosis who have both thrombocytopenia and anemia. #MPN-470. Presented at the Twelfth Annual Meeting of the Society of Hematologic Oncology. September 4-7, 2024; Houston, Texas.