Current Approaches to Transplantation for FLT3-ITD AML

Frugal alignment-free identification of FLT3-internal tandem duplications with FiLT3r

BACKGROUND

Internal tandem duplications in the FLT3 gene, termed FLT3-ITDs, are useful molecular markers in acute myeloid leukemia (AML) for patient risk stratification and follow-up. FLT3-ITDs are increasingly screened through high-throughput sequencing (HTS) raising the need for robust and efficient algorithms. We developed a new algorithm, which performs no alignment and uses little resources, to identify and quantify FLT3-ITDs in HTS data.

RESULTS

Our algorithm (FiLT3r) focuses on the k-mers from reads covering FLT3 exons 14 and 15. We show that those k-mers bring enough information to accurately detect, determine the length and quantify FLT3-ITD duplications. We compare the performances of FiLT3r to state-of-the-art alternatives and to fragment analysis, the gold standard method, on a cohort of 185 AML patients sequenced with capture-based HTS. On this dataset FiLT3r is more precise (no false positive nor false negative) than the other software evaluated. We also assess the software on public RNA-Seq data, which confirms the previous results and shows that FiLT3r requires little resources compared to other software.

CONCLUSION

FiLT3r is a free software available at https://gitlab.univ-lille.fr/filt3r/filt3r . The repository also contains a Snakefile to reproduce our experiments. We show that FiLT3r detects FLT3-ITDs better than other software while using less memory and time.

Stepping out of antiquity: An update on emerging drugs for the treatment of polycythemia vera

Introduction: Polycythemia vera is a chronic hematologic malignancy frequently presented with constitutional symptoms and associated with an increased risk of thrombosis, hemorrhage, and progression to myelofibrosis or acute myeloid leukemia. Current treatment strategies reduce thrombohemorrhagic risk by controlling blood counts and inhibiting platelets, but often fail to address disease-related symptoms or biologically modify the disease.Areas covered: We review the current paradigm for treating polycythemia vera, highlight areas of unmet need, review therapeutic agents in late stage clinical development, and provide an overarching view of how these emerging agent may fit into the future armamentarium of polycythemia vera treatments.Expert opinion: The shift from focusing solely on secondary prevention of thrombohemorrhagic events to a comprehensive treatment strategy that additionally aims to improve quality of life and prevent disease progression has resulted in a rapidly evolving therapeutic landscape that promises to move the treatment of polycythemia vera out of antiquity into the modern age.

Clinical Outcomes in Patients with FLT3-ITD-Mutated Relapsed/Refractory Acute Myelogenous Leukemia Undergoing Hematopoietic Stem Cell Transplantation after Quizartinib or Salvage Chemotherapy in the QuANTUM-R Trial

Despite the substantial clinical activity of fms-related tyrosine kinase 3 (FLT3) inhibitors in relapsed or refractory (R/R) FLT3-ITD‒positive acute myelogenous leukemia (AML), durable remissions and prolonged survival in this population require allogeneic hematopoietic stem cell transplantation (allo-HSCT). Quizartinib, a once-daily oral, highly potent, and selective FLT3 inhibitor, significantly prolonged overall survival (OS) and improved clinical benefit compared with salvage chemotherapy (median OS, 6.2 months versus 4.7 months; hazard ratio [HR], .76; 95% confidence interval [CI], .58 to .98; P = .018; composite complete remission [CRc] rate, 48% versus 27%; median duration of CRc, 2.8 months versus 1.2 months; mortality rate, .8% versus 14% by day 30, 7% versus 24% by day 60) in patients with R/R FLT3-ITD AML in the phase 3 QuANTUM-R trial. In this post hoc analysis, we described the characteristics of and clinical outcomes in patients who underwent on-study HSCT in QuANTUM-R at the investigator's discretion and institutional practices. Of 367 randomized patients, 78 (32%) in the quizartinib arm and 14 (11%) in the salvage chemotherapy arm underwent on-study allo-HSCT without any intervening therapy for AML after quizartinib or study-specified salvage chemotherapy. Pooled data of patients from both treatment arms showed a longer median overall survival (OS) in transplant recipients versus those treated without allo-HSCT (12.2 months versus 4.4 months; HR, .315; 95% CI, .233 to .427). Pooled data also showed a longer median OS in patients with a last recorded response of CRc before allo-HSCT versus patients without a CRc (20.1 months versus 8.8 months; HR, .506; 95% CI, .296 to .864). By treatment arm, the median OS was 25.1 months with quizartinib and 20.1 months with salvage chemotherapy in patients with a last recorded response of CRc before allo-HSCT. Forty-eight patients in the quizartinib arm continued quizartinib treatment after allo-HSCT. In the 31 patients with a last recorded response of CRc before allo-HSCT who continued quizartinib after allo-HSCT, the median OS was 27.1 months. Continuation of quizartinib after allo-HSCT was tolerable, and no new safety signals were identified. These results suggest that post-transplantation survival following salvage chemotherapy and quizartinib treatment are similar. However, quizartinib response occurs more frequently than with salvage chemotherapy, potentially allowing more patients to undergo transplantation and achieve durable clinical benefit. In addition, post-transplant quizartinib was found to be tolerable and may be associated with prolonged survival in some patients, highlighting its potential value in the management of patients with FLT3-ITD R/R AML.