MPN-236: Different Treatment Approaches to Blast-Phase Myeloproliferative Neoplasms

Abstract

Context: Transformation to acute myeloid leukemia (AML) occurs in 5–20% of patients with myeloproliferative neoplasms (MPN). Several retrospective studies have reported poor survival in blast-phase MPN (MPN-BP) in the range of 3 to 6 months that is not significantly impacted by intensive chemotherapy. Current guidelines favor treatment with a hypomethylating agent (HMA), but survival remains poor, and allogeneic stem cell transplant (ASCT) holds the only potential for long-term survival. Objective: To describe the clinical characteristics and overall survival of MPN-BP according to different treatment approaches. Design: Single-institution, retrospective analysis of 70 MPN patients who progressed to blast phase and presented to our institution between 2001 and 2020. Transformation to AML was defined as >20% myeloblasts in peripheral blood or bone marrow. We stratified the patients according to initial treatment strategy for AML. Baseline variables were compared between groups. Median overall survival (mOS) was measured from time of AML diagnosis to date of death. Kaplan-Meier plots were created to compare mOS. Results: Among 70 MF patients who progressed to AML, initial treatment was: 19 best supportive care (BSC), 25 HMA (20 HMA only and 5 HMA + venetoclax), and 26 intensive chemotherapy (12 patients received 7+3, 12 received CLAG/CLAG-M, 2 received CPX-351). Patients receiving intensive chemotherapy were younger than those receiving BSC or HMA (64 years vs 74 years; p=0.002) and proceeded to ASCT more frequently (46% vs 5%; p Conclusions: In MPN-BP, the receipt of an ASCT primarily influenced OS. Additionally, patients receiving treatment had superior outcomes to those who received BSC. Intensive chemotherapy is a reasonable approach in younger patients, as it can provide an effective bridge to ASCT.