There is a paucity of data regarding the impact of mutations on outcomes in accelerated-phase (AP) and blast-phase (BP) myeloproliferative neoplasms (MPNs). Moreover, it is unknown whether mutational status affects survival, as seen in chronic-phase MPNs. Therefore, we performed a retrospective analysis of all patients treated at our institution with AP/BP MPNs (N = 122; AP = 14; BP = 108) to comprehensively describe the mutational profile and correlate with clinical outcomes. Targeted sequencing with a 54-gene panel was performed. Forty-four patients were treated with intensive therapy, 27 with nonintensive therapy, and 51 with best supportive care (BSC). The most common mutation was JAK2V617F, occurring in 55% of subjects; CALR was found in 13% of patients and MPL in 6%. Thirty-two (26%) patients were triple negative. Other frequently mutated genes were ASXL1 (30%), TET2 (25%), SRSF2 (22%), RUNX1 (20%), and TP53 (17%). Mutations in 1, 2, 3, and ≥4 genes were seen in 15%, 13%, 25%, and 46% of patients, respectively. There was no difference in survival between patients treated with intensive vs nonintensive therapy, and the benefit of intensive therapy was limited to patients who were able to undergo transplantation. TP53 was the only individual mutation to correlate with shorter overall survival (hazard ratio, 1.89; P = .03). In the multivariate analysis, mutated TP53, ≥4 mutations, low albumin, increased peripheral blood blasts, ≥3 cytogenetic abnormalities, and BSC were associated with shorter survival. In conclusion, mutational data enhance the understanding of patients with AP/BP MPN who are likely to benefit from current therapeutic options.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is incurable with conventional therapies. Limited retrospective data have shown durable remissions after haematopoietic cell transplantation (HCT) [allogeneic (allo) or autologous (auto)]. We conducted a multicentre retrospective study in BPDCN patients treated with allo-HCT and auto-HCT at 8 centres in the United States and Canada. Primary endpoint was overall survival (OS). The population consisted of 45 consecutive patients who received an allo-HCT (n = 37) or an auto-HCT (n = 8) regardless of age, pre-transplant therapies, or remission status at transplantation. Allo-HCT recipients were younger (50 (14-74) vs. 67 (45-72) years, P = 0·01) and had 1-year and 3-year OS of 68% [95% confidence interval (CI) = 49-81%] and 58% (95% CI = 38-75%), respectively. Allo-HCT in first complete remission (CR1) yielded superior 3-year OS (versus not in CR1) [74% (95% CI = 48-89%) vs. 0, P < 0·0001]. Allo-HCT outcomes were not impacted by regimen intensity [3-year OS for myeloablative conditioning = 61% (95% CI = 28-83%) vs. reduced-intensity conditioning = 55% (95% CI = 28-76%)]. One-year OS for auto-HCT recipients was 11% (95% CI = 8-50%). These results demonstrate efficacy of allo-HCT in BPDCN, especially in patients in CR1. Pertaining to auto-HCT, our results suggest lack of efficacy against BPDCN, but this observation is limited by the small sample size. Larger prospective studies are needed to better define the role of HCT in BPDCN.

Key Points ASXL1/EZH2, transfusion dependence, and a high prognostic risk score predict shorter TTF in MF patients on JAK1/2 inhibitors. These clinical and genetic factors were also associated with decreased overall survival.

Core-binding factor acute myeloid leukemia is characterized by t(8;21) or inv(16) and the fusion proteins RUNX1-RUNX1T1 and CBFB-MYH11. International guidelines recommend monitoring for measurable residual disease every 3 months for 2 years after treatment. However, it is unknown if serial molecular monitoring can predict and prevent morphologic relapse. We conducted a retrospective single-center study of 114 patients in complete remission who underwent molecular monitoring with RT-qPCR of RUNX1-RUNX1T1 or CBFB-MYH11 transcripts every 3 months. Morphologic relapse was defined as re-emergence of >5% blasts and molecular relapse as ≥1 log increase in transcript level between 2 samples. Over a median follow-up time of 3.7 years (range 0.2-14.3), remission persisted in 71 (62.3%) patients but 43 (37.7%) developed molecular or morphologic relapse. Patients who achieved <3 log reduction in RUNX1-RUNX1T1 or CBFB-MYH11 transcripts at end of chemotherapy had a significantly higher risk of relapse compared to patients who achieved ≥3 log reduction (61.1% vs. 33.7%, p=0.004). The majority of relapses (74.4%, n=32) were not predicted by molecular monitoring and occurred rapidly with <100 days from molecular to morphologic relapse. Molecular monitoring enabled the detection of impending relapse and permitted pre-emptive intervention prior to morphologic relapse in only 11 (25.6%) patients. The current practice of molecular monitoring every 3 months provided insufficient lead-time to identify molecular relapses and prevent morphologic relapse in the majority of patients with core-binding factor acute myeloid leukemia treated at our institution. Further research is necessary to determine the optimal monitoring strategies for these patients.