Outcomes of blast-phase MPN and JAK2, MPL, and CALRmutated de novo AML: A propensity score-adjusted cohort study.

Abstract

6526 Background: Progression to blast phase (BP) occurs in about 10% of patients with BCR-ABL-negative myeloproliferative neoplasms (MPN) and is associated with an extremely poor prognosis with no defined standard of care. The VIALE-A trial, which showed that venetoclax (VEN) improves overall survival (OS) in patients with acute myeloid leukemia (AML) when combined with azacitidine, excluded patients with MPN-BP. Rarely, patients develop de novo AML with a genetic profile like an MPN, harboring JAK2, MPL, or CALR mutations. However, there are a lack of data on the outcomes of these patients. Methods: We conducted a single-center retrospective cohort study to compare composite complete response (CCR), OS and event-free survival (EFS) of patients with MPN-BP or de novo AML with underlying JAK2, MPL, or CALR mutations (AML-D-MPN). CCR was defined as complete response (CR) or CR with incomplete count recovery. Propensity score (PS) modeling was used to adjust for baseline characteristics at AML diagnosis: age, sex, race, comorbidities, ECOG status, cytogenetics, and underlying mutations. Results: Of 750 patients treated from 2015 to 2023, 61 had MPN-BP and 12 had AML-D-MPN. The table describes baseline characteristics. The median time for MPN to BP transformation was 8 years (IQR: 2.8-13.6). With a median follow-up of 8.2 months (mo) (95CI: 1.6-59.6), the median OS for MPN-BP was 4.8 mo (95CI: 2.7-8) and for AML-D-MPN was 6.1 mo (95CI: 1.6-NC). In the MPN-BP, 40 received therapy, which included: intensive regimen [7+3 (n=13); CPX-351 (n=1)], hypomethylating agents (HMA) (n=11), HMA+VEN (n=11) and others (n=4). All AML-D-MPN received therapy, which included 7+3 (n=4), HMA (n=1), HMA+VEN (n=2), and others (n=5). In the whole treated population (n=52), the unadjusted CCR was 60% in intensive regimen, 20% in HMA, 20% in HMA+VEN and 0% in others (p=0.3). The PS-adjusted median (m) OS in mo (95%CI) was: 2.6 (1.4-NC) in intensive regimen, 6.2 (1.2-NC) in HMA, 15 (10-15) in HMA+VEN and 1.7 (0.46-NC) in others (p=0.1). The adjusted m-EFS in the same treatment groups was 1.5 (0.43-NC), 6.2 (1.2-NC), 15 (4.3-15) and 0.92 (0.46-NC) (p=0.16), respectively. In MPN-BP group, the adjusted m-EFS in mo (95%CI) was: 0.62 (0.43-NC) in the intensive regimen, 6.2 (1.2-NC) in HMA, 15 (4.2-15) in HMA+VEN and 0.92 (0.92-NC) in others (p=0.25). Conclusions: Patients with MPN-BP and AML-D-MPN have poor survival with similar responses to therapy. These patients have variable outcomes with different treatments; however, there is a trend toward improved survival with the use of HMA+VEN. [Table: see text]