Prognostic Factors and Clinical Outcomes in Patients with Blast Phase Chronic Myeloid Leukemia.

BACKGROUND: Given the low incidence of patients with advanced chronic myeloid leukemia (CML), comprehensive clinical characteristics and outcomes of cohort studies of patients diagnosed with blast phase chronic myeloid leukemia (BP-CML) are limited. We examined the clinical features of blast phase CML, including the TKI selection, treatment response, and whether they have had hematopoietic stem cell transplantation (HSCT) or not. METHODS: We performed a retrospective cohort study, including BP-CML patients diagnosed in our center from January 2013 to December 2022. Clinical features, treatment therapy, and overall survival (OS) were investigated. RESULTS: Out of the 11 patients, 2 were myeloid type, eight patients were B-lymphoid, and one was T-lymphoid. Four patients suffered from chromosome abnormalities. Four patients were identified with BCR-ABL1 kinase domain mutation, including T315I, E255K, M244v, and E279K. The overall CR, CRi, PR, and MLFS rates were 9%, 54%, 27%, and 9%, respectively. The median follow-up was 21 months (9.5 - 33 months). At the end of the follow-up time, seven patients died. CML patients with lymphoids tended to get a better OS than patients with a type of myeloid, but the difference was not statistically significant (p > 0.05). Patients who received HSCT had an improved OS by two years compared to those who had not received HSCT. CONCLUSIONS: The prognosis of BP-CML patients was poor. Given the rarity of BP-CML and the limitation of clinical trial data, large-scale multi-center prospective studies are urgently needed to confirm and improve the treatment of patients with BP-CML in the future.

ETV6::ABL1 positive myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions (MLN-TK) with blast crisis treated with flumatinib mesylate.

ETV6::ABL1 fusion gene is a rare but recurrent genomic rearrangement in hematological malignancies with poor prognosis. Here, we report 1 case of Ph negative myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions (MLN-TK) who carry ETV6::ABL1 fusion gene. The patient achieved clinical remission after treatment with imatinib. However, disease progression of blast crisis was observed around 2 years later. The patient was treated with second-generation tyrosine kinase inhibitor of flumatinib, yielded a short term second therapeutic response. ETV6::ABL1 positive myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions (MLN-TK) is rare and may be misdiagnosed by conventional cytogenetical analysis. Early treatment with TKIs, particularly second-generation TKIs, may be beneficial to improve treatment results.

Assessment of Total Antioxidant Capacity, 8-Hydroxy-2'-deoxy-guanosine, the Genetic Landscape, and Their Associations in BCR::ABL-1-Negative Chronic and Blast Phase Myeloproliferative Neoplasms.

Myeloproliferative neoplasms (MPNs), namely, polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), are clonal stem cell disorders defined by an excessive production of functionally mature and terminally differentiated myeloid cells. MPNs can transform into secondary acute myeloid leukemia (sAML/blast phase MPN) and are linked to alterations in the redox balance, i.e., elevated concentrations of reactive oxygen species and markers of oxidative stress (OS), and changes in antioxidant systems. We evaluated OS in 117 chronic phase MPNs and 21 sAML cases versus controls by measuring total antioxidant capacity (TAC) and 8-hydroxy-2'-deoxy-guanosine (8-OHdG) concentrations. TAC was higher in MPNs than controls (p = 0.03), particularly in ET (p = 0.04) and PMF (p = 0.01). MPL W515L-positive MPNs had higher TAC than controls (p = 0.002) and triple-negative MPNs (p = 0.01). PMF patients who had treatment expressed lower TAC than therapy-free subjects (p = 0.03). 8-OHdG concentrations were similar between controls and MPNs, controls and sAML, and MPNs and sAML. We noted associations between TAC and MPNs (OR = 1.82; p = 0.05), i.e., ET (OR = 2.36; p = 0.03) and PMF (OR = 2.11; p = 0.03), but not sAML. 8-OHdG concentrations were not associated with MPNs (OR = 1.73; p = 0.62) or sAML (OR = 1.89; p = 0.49). In conclusion, we detected redox imbalances in MPNs based on disease subtype, driver mutations, and treatment history.

Treatment approach and outcomes of patients with accelerated/blast-phase myeloproliferative neoplasms in the current era.

ABSTRACT: Progression of myeloproliferative neoplasms (MPNs) to accelerated or blast phase is associated with poor survival outcomes. Since 2017 there have been several therapies approved for use in acute myeloid leukemia (AML); these therapies have been incorporated into the management of accelerated/blast-phase MPNs (MPN-AP/BP). We performed a multicenter analysis to investigate outcomes of patients diagnosed with MPN-AP/BP in 2017 or later. In total, 202 patients were identified; median overall survival (OS) was 0.86 years. We also analyzed patients based on first-line treatment; the 3 most common approaches were intensive chemotherapy (n = 65), DNA methyltransferase inhibitor (DNMTi)-based regimens (n = 65), and DNMTi + venetoclax-based regimens (n = 54). Median OS was not significantly different by treatment type. In addition, we evaluated response by 2017 European LeukemiaNet AML criteria and 2012 MPN-BP criteria in an effort to understand the association of response with survival outcomes. We also analyzed outcomes in 65 patients that received allogeneic hematopoietic stem cell transplant (allo-HSCT); median OS was 2.30 years from time of allo-HSCT. Our study demonstrates that survival among patients with MPN-AP/BP is limited in the absence of allo-HSCT even in the current era of therapeutics and underscores the urgent need for new agents and approaches.

Targeting MCL1-driven anti-apoptotic pathways overcomes blast progression after hypomethylating agent failure in chronic myelomonocytic leukemia.

RAS pathway mutations, which are present in 30% of patients with chronic myelomonocytic leukemia (CMML) at diagnosis, confer a high risk of resistance to and progression after hypomethylating agent (HMA) therapy, the current standard of care for the disease. Here, using single-cell, multi-omics technologies, we seek to dissect the biological mechanisms underlying the initiation and progression of RAS pathway-mutated CMML. We identify that RAS pathway mutations induce transcriptional reprogramming of hematopoietic stem and progenitor cells (HSPCs) and downstream monocytic populations in response to cell-intrinsic and -extrinsic inflammatory signaling that also impair the functions of immune cells. HSPCs expand at disease progression after therapy with HMA or the BCL2 inhibitor venetoclax and rely on the NF-κB pathway effector MCL1 to maintain survival. Our study has implications for the development of therapies to improve the survival of patients with RAS pathway-mutated CMML.

A comparative analysis of the clinical and genetic profiles of blast phase BCR::ABL1-negative myeloproliferative neoplasm and acute myeloid leukemia, myelodysplasia-related.

INTRODUCTION: The classic Philadelphia chromosome-negative myeloproliferative neoplasms (Ph (-) MPNs), have variable potential for progression to the blast phase (MPN-BP) of the disease. Except initiated by distinct driver mutations, MPN-BP frequently carry similar genetic abnormalities defining acute myeloid leukemia myelodysplasia-related (AML-MR). Because of dissimilar initial pathogenesis, MPN-BP and AML-MR are retained under different disease categories. To determine if separately classifying these entities is justified, we compare MPN-BP with AML-MR patients based on mutational landscape and clinical parameters. METHODS: 104 MPN-BP patients and 145 AML-MR patients were identified with available clinical, cytogenetic, and genetic data. RESULTS: AML-MR patients presented with a higher blast count (median, 51% vs. 30%) while MPN-BP patients had higher WBC counts, platelet counts and bone marrow cellularity (all p<0.0001). Patients with MPN-BP showed similar genetic mutations with similar mutation pattern (functional domain, hotspot and locus involved by the mutations) but a different mutation rate from AML-MR, with more frequent JAK2, CALR, MPL, ASXL1, IDH2, SETBP1 and SRSF2 mutations and less frequent TP53 and DNMT3A mutations. The overall survival (OS) of MPN-BP (OS post-BP-progression) is comparable to that of AML-MR (median OS, 9.5 months vs. 13.1 months, p=0.20). In addition, the subgroups of MPN-BP show similar OS as AML-MR. When harboring certain mutation such as TP53, ASXL1, DNMT3A, TET2, RUNX1, IDH1, IDH2, EZH2, U2AF1, BCOR and SRSF2, MPN-BP and AML-MR patients carrying the same somatic mutation show no difference in OS. CONCLUSION: MPN-BP and AML-MR harbor similar somatic mutations and clinical outcomes, suggesting a unified clinical disease entity.

Management and outcome of patients with chronic myeloid leukemia in blast phase in the tyrosine kinase inhibitor era - analysis of the European LeukemiaNet Blast Phase Registry.

Blast phase (BP) of chronic myeloid leukemia (CML) still represents an unmet clinical need with a dismal prognosis. Due to the rarity of the condition and the heterogeneity of the biology and clinical presentation, prospective trials and concise treatment recommendations are lacking. Here we present the analysis of the European LeukemiaNet Blast Phase Registry, an international collection of the clinical presentation, treatment and outcome of blast phases which had been diagnosed in CML patients after 2015. Data reveal the expected heterogeneity of the entity, lacking a clear treatment standard. Outcomes remain dismal, with a median overall survival of 23.8 months (median follow up 27.8 months). Allogeneic stem cell transplantation (alloSCT) increases the rate of deep molecular responses. De novo BP and BP evolving from a previous CML do show slightly different features, suggesting a different biology between the two entities. Data show that outside clinical trials and in a real-world setting treatment of blast phase is individualized according to disease- and patient-related characteristics, with the aim of blast clearance prior to allogeneic stem cell transplantation. AlloSCT should be offered to all patients eligible for this procedure.

Spotlight on the real-world treatment of CML pts in Germany: a retrospective survey in private oncology practices.

Clinical trials in chronic myeloid leukemia (CML) are usually carried out in specialized centers whereas primary care for patients (pts) with CML is mainly provided by local oncology practices. The aim of this study was to assess treatment practices in pts with CML in the setting of private oncology practices in Germany. We collected data of 819 pts with a confirmed diagnosis (dx) of CML in 2013 or later from 43 practices. At dx, 84.2% (n=690) and 9.4% (n=77) of pts were in chronic or accelerated phase, 0.7% (n=6) had a blast crisis. Molecular monitoring was provided by EUTOS certified laboratories in 87.7% of pts. Typical BCR::ABL1 transcripts were detected in 86.6% (n=709). Molecular response was assessed after 2.8, 6.0, 9.4 and 12.9 m (mean) after start of treatment. Of the pts with available data, 11.1% did not achieve early molecular response and at 18 m, 83.7% had at least a major molecular response. 288 (35.2%) of pts switched to 2nd line (2L) treatment after a mean of 21.0 months. Reasons for 2L treatment were side effects in 43.4% and suboptimal response or failure in 31.4% of pts. 106 pts went on to third line (3L) treatment. 36.8 % of pts switched to and 92.8 % of pts still on 3L treatment achieved BCR::ABL1IS ≤1% at 12 m. In conclusion, in Germany pts with CML are routinely monitored by qPCR and good responses are achieved in the majority. Treatment changes are mainly due to adverse events rather than suboptimal responses.

Chronic Myeloid Leukemia, Version 2.2024, NCCN Clinical Practice Guidelines in Oncology.

Chronic myeloid leukemia (CML) is defined by the presence of Philadelphia chromosome resulting from a reciprocal translocation between chromosomes 9 and 22 [t9;22] that gives rise to a BCR::ABL1 fusion gene. CML occurs in 3 different phases (chronic, accelerated, and blast phase) and is usually diagnosed in the chronic phase in developed countries. Tyrosine kinase inhibitor (TKI) therapy is a highly effective treatment option for patients with chronic phase-CML. The primary goal of TKI therapy in patients with chronic phase-CML is to prevent disease progression to accelerated phase-CML or blast phase-CML. Discontinuation of TKI therapy with careful monitoring is feasible in selected patients. This manuscript discusses the recommendations outlined in the NCCN Guidelines for the diagnosis and management of patients with chronic phase-CML.

De novo accelerated phase of chronic myeloid leukemia should be recognized even in the era of tyrosine kinase inhibitors.

Overall survival of patients classified according to the European LeukemiaNet 2020 classification. Chronic phase (CP), accelerated phase (AP), blast crisis (BC), low risk (LR), intermediate risk (IR), high risk (HR).