Interaction between myelodysplasia-related gene mutations and ontogeny in acute myeloid leukemia.

Accurate classification and risk stratification are critical for clinical decision making in patients with acute myeloid leukemia (AML). In the newly proposed World Health Organization and International Consensus classifications of hematolymphoid neoplasms, the presence of myelodysplasia-related (MR) gene mutations is included as 1 of the diagnostic criteria for AML, AML-MR, based largely on the assumption that these mutations are specific for AML with an antecedent myelodysplastic syndrome. ICC also prioritizes MR gene mutations over ontogeny (as defined in the clinical history). Furthermore, European LeukemiaNet (ELN) 2022 stratifies these MR gene mutations into the adverse-risk group. By thoroughly annotating a cohort of 344 newly diagnosed patients with AML treated at the Memorial Sloan Kettering Cancer Center, we show that ontogeny assignments based on the database registry lack accuracy. MR gene mutations are frequently observed in de novo AML. Among the MR gene mutations, only EZH2 and SF3B1 were associated with an inferior outcome in the univariate analysis. In a multivariate analysis, AML ontogeny had independent prognostic values even after adjusting for age, treatment, allo-transplant and genomic classes or ELN risks. Ontogeny also helped stratify the outcome of AML with MR gene mutations. Finally, de novo AML with MR gene mutations did not show an adverse outcome. In summary, our study emphasizes the importance of accurate ontogeny designation in clinical studies, demonstrates the independent prognostic value of AML ontogeny, and questions the current classification and risk stratification of AML with MR gene mutations.

Venetoclax-based salvage therapy in patients with relapsed/refractory acute myeloid leukemia previously treated with FLT3 or IDH1/2 inhibitors.

FLT3, IDH1 and IDH2 inhibitors as well as venetoclax in combination with hypomethylating agents or low-dose cytarabine have expanded treatment options for patients with acute myeloid leukemia (AML). However, little data exist on the efficacy of venetoclax-based therapies in AML patients previously treated with FLT3 or IDH1/2 inhibitors. In this multicenter, retrospective cohort study, we included 44 patients who received venetoclax-based therapy after FLT3, IDH1 or IDH2 inhibitors. The overall response rate (ORR; composite of complete remission [CR]/CR with incomplete count recovery, partial remission, and morphologic leukemia free state) was 56.8% (18.2% CR) and a median overall survival of 9.2 months. While 6 out of 7 patients with IDH1 mutations who had previously been treated with ivosidenib responded to venetoclax-based therapy, FLT3-ITD mutations were associated with a lower response rate. Our data suggest that venetoclax can be an effective salvage therapy in patients previously treated with IDH1/2 or FLT3 inhibitors.

Efficacy of FLT3 and IDH1/2 inhibitors in patients with acute myeloid leukemia previously treated with venetoclax.

Small molecule inhibitors targeting mutant FLT3, IDH1, and IDH2 as well as venetoclax-based combination therapies have expanded treatment options for patients with acute myeloid leukemia (AML). As the landmark trials leading to the approval of FLT3, IDH1, and IDH2 inhibitors in R/R-AML were conducted prior to the widespread use of venetoclax, it is unclear how these results apply in the current era of venetoclax based therapy frequently being used in the frontline treatment of AML. In this multicenter, retrospective cohort study, we included 53 patients who received FLT3, IDH1 or IDH2 inhibitors after disease progression on venetoclax-based therapy. Among patients treated with targeted agents after venetoclax, the overall response rate (ORR; composite of complete remission [CR]/CR with incomplete count recovery, partial remission, and morphologic leukemia free state) was 17.7 % (n = 9 patients) and median OS of 4.2 months. Eight of 9 patients responding to targeted agents after venetoclax received gilteritinib. None of the patients with RAS pathway mutations responded to targeted agents after venetoclax. Additionally, mutations in TP53 and KRAS were associated with shorter OS among patients treated targeted agents. Our data suggest that response rates to targeted therapies after venetoclax are low and novel therapeutic strategies are warranted.

FLT3 Inhibitors as Maintenance Therapy after Allogeneic Stem-Cell Transplantation.

Mutations in the FLT3 gene are associated with poor prognosis in patients with AML, even after consolidation with allogeneic hematopoietic cell transplantation (alloHCT) in first remission. Treatment failure in FLT3-mutated AML is largely driven by excessive risk of relapse compared to other genetic subtypes, including in patients post-alloHCT. As a result, there is substantial interest in studying posttransplant maintenance therapy in FLT3-mutated AML as an approach to optimize disease control and improve long-term outcomes. Clinical trials utilizing posttransplant FLT3 inhibitors, such as sorafenib and midostaurin, have shown feasibility, safety, and encouraging posttransplant outcomes, and there are ongoing studies using newer-generation tyrosine-kinase inhibitors as posttransplant maintenance therapy. Here, we review the toxicities and efficacy of FLT3 inhibitors as posttransplant maintenance, recommendations on the use of FLT3 inhibitors by international consensus guidelines, and highlight key remaining questions.

Venetoclax in combination with nucleoside analogs in acute myelogenous leukemia.

PURPOSE OF REVIEW: Venetoclax in combination with nucleoside analogs such as hypomethylating agents (HMA) and low-dose cytarabine (LDAC) has led to unprecedented response and survival outcomes in patients with acute myeloid leukemia (AML). This has spurred the development of regimens combining venetoclax with other nucleoside analogs with distinct mechanisms of action. Here, we review older and newer nucleoside analogs, the rationale for their combination with venetoclax, and clinical evidence for the combination when available. RECENT FINDINGS: Venetoclax with HMA prolonged survival in a phase 3 study. Additionally, biologic correlates of response and resistance to venetoclax with HMA have been identified. The addition of venetoclax to standard intensive regimens containing higher doses of cytarabine and purine nucleoside analogs are safe and induce very high rates of remission and measurable residual disease negativity (MRD) negativity in newly diagnosed and relapsed/refractory AML. Investigational nucleoside analogs aim to improve upon the safety, bioavailability, or efficacy of approved venetoclax combinations and are currently being evaluated in clinical studies. SUMMARY: The development of venetoclax with HMA has transformed care for elderly adults with AML and opened the door for novel combinations of venetoclax with other nucleoside analogs. Further clinical studies are needed to see if these novel combinations further improve outcomes in AML particularly for patients with high-risk disease.

Treatment outcomes for patients with myelodysplastic syndrome/myeloproliferative neoplasms with ring sideroblasts and thrombocytosis.

Myelodysplastic syndrome/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis (MDS/MPN-RS-T) is characterized by anemia, ring sideroblast erythroid precursors, and persistent thrombocytosis. Case reports suggest lenalidomide may be effective in treating MDS/MPN-RS-T. We evaluated a large series of patients with MDS/MPN-RS-T to compare hematological improvement (HI) response rates among different drug therapies including lenalidomide. We identified 167 patients with MDS/MPN-RS-T. Among the patients tested, 84% had SF3B1 mutations and 43% had JAK2 V617F mutations. The median OS for the cohort was 81 months. Overall, 76 patients (46%) received erythropoiesis-stimulating agents (ESAs), 47 patients (28%) received lenalidomide, and 45 patients (27%) received hypomethylating agents (HMAs). The HI rates were 58%, 53%, and 24%, respectively. The median duration of treatment was 11 months for lenalidomide compared to 6 months for HMAs. Rates of HI improvement were higher in patients with MDS/MPN-RS-T treated with ESAs or lenalidomide, in comparison to those treated with HMAs.