The RTK-RAS signaling pathway is enriched in patients with rare acute myeloid leukemia harboring t(16;21)(p11;q22)/FUS::ERG.

Acute myeloid leukemia (AML) with t(16;21)(p11;q22)/FUS::ERG is a rare AML subtype associated with poor prognosis. However, its clinical and molecular features remain poorly defined. We determined the clinicopathological, genomic, and transcriptomic characteristics and outcomes of patients with AML harboring FUS::ERG at our center. Thirty-six AML patients harboring FUS::ERG were identified, with an incidence rate of 0.3%. These patients were characterized by high lactate dehydrogenase levels (median: 838.5 U/L), elevated bone marrow blast counts (median: 71.5%), and a CD56-positive immunophenotype (94.3%). Notably, we found that RTK-RAS GTPase (RAS) pathway genes, including NRAS (33%) and PTPN11 (24%), were frequently mutated in this subtype. Transcriptome analysis revealed enrichment of the phosphatidylinositol-3-kinase-Akt (PI3K-Akt), mitogen-activated protein kinase (MAPK), and RAS signaling pathways and upregulation of BCL2, the target of venetoclax, in FUS::ERG AML compared to RUNX1::RUNX1T1 AML, a more common AML subtype with good prognosis. The median event-free survival in patients with FUS::ERG AML was 11.9 (95% confidence interval [CI]: 9.0-not available [NA]) months and the median overall survival was 18.2 (95% CI: 12.4-NA) months. Allogeneic hematopoietic stem cell transplantation failed to improve outcomes. Overall, the high incidence of RTK-RAS pathway mutations and high expression of BCL2 may indicate promising therapeutic targets in this high-risk AML subset.

Treatment Patterns and FLT3 Mutation Testing Among Patients with Acute Myeloid Leukemia in China: A Retrospective Observational Study.

Introduction: For acute myeloid leukemia (AML), prognosis is particularly poor in patients harboring FMS-like tyrosine kinase 3 (FLT3) gene mutations, though routine screening for these mutations at diagnosis has been shown to be insufficient. The understanding of the impact of FLT3 mutations on treatment decisions is limited. Methods: In this retrospective, observational study, we investigated the key epidemiological characteristics, treatment patterns and responses among adult patients with newly diagnosed (ND) AML in China, who initiated treatment from January 1, 2015, to December 31, 2019, or progressed to relapsed/refractory (R/R) AML by December 31, 2020. Results: Of the 853 ND AML patients included, 63.4% were screened for FLT3 status, and 20.1% tested positive (FLT3MUT) at initial diagnosis. Of 289 patients who progressed to R/R AML during the study period, 24.9% were screened at the diagnosis of R/R AML, and 19.4% tested positive; 20.5% of screened patients changed FLT3 status at first diagnosis of R/R AML. Initial treatment regimens or treatment responses did not seem to differ in patients with ND AML by FLT3 mutation status. In patients with R/R AML, there was an apparent difference in second-line treatment choices by FLT3 mutation status; however, the number of FLT3-mutated patients were limited to demonstrate any meaningful distinction. FLT3-mutated R/R AML was associated with shorter relapse time. Conclusion: Study findings showed that there was a lack of routine testing for FLT3 mutations at first diagnosis of R/R AML, and initial treatment decisions did not differ by FLT3 mutation status. Given the clinical burden of FLT3MUT, likelihood of FLT3 status changes, and emerging FLT3 inhibitors, further routine FLT3 screening is needed to optimize treatment of R/R AML.

A novel subclonal rearrangement of the STRN3::PDGFRB gene in de novo acute myeloid leukemia with NPM1 mutation and its leukemogenic effects.

Chromosome translocations in the 5q31-33 region are associated with a range of hematologic malignancies, some of which involve the platelet-derived growth factor receptor beta (PDGFRB) gene. We report a case of acute myeloid leukemia (AML) with a mutation in the NPM1 gene (NPM1-mut AML) and a subclonal gene rearrangement involving the PDGFRB gene. We identified a novel fusion gene, STRN3::PDGFRB, resulting from t(5;14) (q32;q12) chromosomal rearrangement. Sequential FISH confirmed that ~15% of leukemic cells carried the PDGFRB gene rearrangement, which suggests that STRN3::PDGFRB is a previously unreported fusion gene in a subclone. Reverse transcription PCR (RT-PCR) and Sanger sequencing confirmed that the fusion gene consisted of STRN3 exon 7 fused to PDGFRB exon 11, resulting in a chimeric protein containing the coiled-coil domain of striatin-3 and the transmembrane and intracellular tyrosine kinase domains of the PDGFRB. The new protein exhibited distinct cytoplasmic localization and had leukemogenic effects, as demonstrated by its ability to transform Ba/F3 cells to growth factor independence and cause a fatal myelodysplastic/myeloproliferative neoplasm (MDS/MPN)-like disease in mice, which then transformant to T-cell lymphoblastic lymphoma in secondary recipients. Ba/F3 cells expressing STRN3::PDGFRB or ETV6::PDGFRB were sensitive to tyrosine kinase inhibitors (TKIs) and selinexor, but in vitro experiments showed that the combination of imatinib and selinexor had a marked synergistic effect, although only the imatinib alone group could prolong the survival of T-cell blast transformation recipient mice. Our findings demonstrate the leukemogenic effects of the novel fusion gene and provide insights into the clone evolution of AML, which can be influenced by therapy selection. Furthermore, our results provide insight into the potential therapeutic options for patients with this type of mutation, as well as the need for careful consideration of treatment selection to prevent undesirable side effects.

[Clinical Analysis of SET-NUP214 Fusion Gene Positive Patients with Acute Leukemia].

OBJECTIVE: To analyze the characteristics and prognosis of acute leukemia(AL) with SET-NUP214 fusion gene. METHODS: The clinical data of 17 patients over 14 years old newly diagnosed with SET-NUP214 positive AL admitted in Institute of Hematology and Blood Diseases Hospital from August 2017 to May 2021 were analyzed retrospectively. RESULTS: Among the 17 SET-NUP214 positive patients, 13 cases were diagnosed as T-ALL (ETP 3 cases, Pro-T-ALL 6 cases, Pre-T-ALL 3 cases, Medullary-T-ALL 1 case), AML 3 cases (2 cases M5, 1 case M0) and ALAL 1 case. Thirteen patients presented extramedullary infiltration at initial diagnosis. All 17 patients received treatment, and a total of 16 cases achieved complete remission (CR), including 12 cases in patients with T-ALL. The total median OS and RFS time were 23 (3-50) months and 21 (0-48) months, respectively. Eleven patients received allogeneic hematopoietic stem cell transplantation(allo-HSCT), with median OS time of 37.5 (5-50) months and median RFS time of 29.5 (5-48) months. The median OS time of 6 patients in chemotherapy-only group was 10.5 (3-41) months, and median RFS time of 6.5 (3-39) months. The OS and RFS of patients with transplantation group were better than those of chemotherapy-only group (P=0.038). Among the 4 patients who relapsed or refractory after allo-HSCT, the SET-NUP214 fusion gene did not turn negative before transplantation. While, in the group of 7 patients who have not relapsed after allo-HSCT till now, the SET-NUP214 fusion gene expression of 5 patients turned negative before transplantation and other 2 of them were still positive. CONCLUSION: The fusion site of SET-NUP214 fusion gene is relatively fixed in AL patients, often accompanied by extramedullary infiltration. The chemotherapy effect of this disease is poor, and allo-HSCT may improve its prognosis.

A short report of novel RARG-HNRNPM fusion gene in resembling acute promyelocytic leukemia.

BACKGROUND: Resembling acute promyelocytic leukemia (APL) is a unique subtype of APL who sharing clinical, morphological, and immunophenotypic features with typical APL, but lacking evidence of PML-RARA fusion gene and usually insensitive to arsenic trioxide (ATO) and all-trans retinoic acid (ATRA). For years, RARA, RARB and RARG rearrangement were found in resembling APL continually. The confirmed partner genes of RARG rearrangement included CPSF6, NUP98, NPM1, PML, and HNRNPC. These patients were a group of resembling APL with rare molecular genetic abnormality and unfavorable prognosis. They usually were resistant to ATO and ATRA but partially sensitive to anthracycline-based chemotherapy. CASE PRESENTATION: We reported a 25-year-old female patient with a novel fusion gene RARG-HNRNPM (RARG chr12:53606869: -; HNRNPM chr19: 8527413: + based on GRCh37/hg19 Assembly) through RNA-seq as resembling APL. The patient with RARG-HNRNPM was benefited from a combined chemotherapy homoharringtonine, cytarabine, and aclacinomycin (HAA) regimen with no relapse. DISCUSSION AND CONCLUSIONS: RARG rearrangement resembling APL are various. The treatment should be switched from ATRA/ATO to AML combined chemotherapy regimen early.

The clinical characteristics and prognosis in adult Ph negative acute lymphoblastic leukemia with TP53 aberrations.

Very few reports elucidate the prognosis of patients with TP53 aberrations using both measurable residual disease (MRD) and the status of having undergone allogeneic hematopoietic stem cell transplantation (allo-SCT). In this study, aberrations of TP53 were analyzed using next-generation sequencing (NGS) and fluorescence in situ hybridization (FISH) in patients with Philadelphia chromosome-negative (Ph-) ALL enrolled in a prospective single-arm clinical trial at our leukemia center. We analyzed the survival of the patients grouped according to the MRD level at the third month and whether or not received allo-SCT. We found that allo-SCT could improve the OS in patients with TP53 aberrations; Patients having negative MRD at the third month still showed worse 3-year OS and 3-year DFS without undergoing allo-SCT, which is different from previous studies, moreover, the prognostic significance of TP53 deletions was as important as TP53 mutations, the importance of screening both TP53 deletions and mutations in adult Ph- ALL at diagnosis should be emphasized.

The prognostic factors in acute myeloid leukaemia with double-mutated CCAAT/enhancer-binding protein alpha (CEBPAdm).

The prognostic factors to stratify acute myeloid leukaemia (AML) with double-mutated CCAAT/enhancer-binding protein alpha (CEBPAdm) into different risk groups remains to be determined. In this retrospective study, we evaluated 171 consecutive patients with newly diagnosed AML with CEBPAdm by a Cox proportional hazards regression model. In univariate analyses, colony stimulating factor 3 receptor (CSF3R) and Wilms tumour 1 (WT1) mutations were associated with poor relapse-free survival (RFS). The induction regimens including homoharringtonine (omacetaxine mepesuccinate) or intermediate-dose cytarabine was associated with favourable RFS and overall survival (OS). The induction regimen including both homoharringtonine and intermediate-dose cytarabine was associated with the most favourable RFS (3-year RFS 84.7%) and OS (3-year OS 92.8%) compared to the conventional cytarabine and daunorubicin regimen (3-year RFS 27.7%, hazard ratio [HR] 0.126, 95% confidence interval [CI] 0.051-0.313, Wald p < 0.001; and 3-year OS 56.4%, HR 0.179, 95% CI 0.055-0.586, Wald p = 0.005). In multivariate analyses, the induction regimen including intermediate-dose cytarabine (HR 0.364, 95% CI 0.205-0.646, Wald p < 0.001) and CSF3R mutations (HR 2.667, 95% CI 1.276-5.572, Wald p = 0.009) were independently associated with RFS. Taken together, we found that induction regimen and CSF3R mutations were independent prognostic factors for AML with CEBPAdm.

Efficacy of combination of venetoclax with azacitidine or chemotherapy in refractory/relapse acute leukemias of ambiguous lineage, not otherwise specified.

Acute leukemias of ambiguous lineage, not otherwise specified (ALAL-NOS) is a rare type of acute leukemia. Management of relapse/refractory (R/R) patients is still challenging.traditional chemotherapy treatment is not effective. In this paper, we reported 6 R/R patients diagnosed as ALAL-NOS in our hospital, who were treated with venetoclax based treatment (venetoclax combining with azacitidine or chemotherapy). All 6 patients achieved CR. Five of the six patients received allo-HSCT, four patients were still alive in CR until the follow-up day. Our data provide preliminary evidence and show that venetoclax based regimens are effective and safety in patients with R/R ALAL-NOS.

Evaluation of pretreatment telomere length as a prognostic marker in intermediate-risk acute myeloid leukemia.

INTRODUCTION: The current framework for risk stratification is still insufficient for highly heterogeneous intermediate-risk acute myeloid leukemia (IRC-AML), which lacks specific genomic abnormalities. METHODS: In order to incorporate novel biomarkers to refine current risk stratification strategies for patients with this subtype, we investigated pretreatment telomere length (TL), which is essential for maintaining genomic stability, in 204 adults with de novo AML (non-acute promyelocytic leukemia). RESULTS: We found that TL measured at diagnosis did not decrease with advancing age in 204 patients with AML (R2  = 0.001, P = .695). A multivariate analysis demonstrated that short TL was independently associated with an inferior relapse-free survival (hazard ratio [HR] 3.08, 95% confidence interval [CI] 1.48-6.41, P = .003); event-free survival (HR 2.14, 95% CI 1.12-4.08, P = .021); and overall survival (HR 2.26, 95% CI 1.09-4.67, P = .028) in IRC-AML patients. In addition, IRC-AML patients with short TL also exhibited an increased cumulative incidence of hematologic relapse (HR 2.32, 95% CI 1.08-5.26, P = .032). CONCLUSION: Short TL is an independent prognostic factor for poor prognosis in patients with IRC-AML and may represent a novel mechanism that links genomic stability and disease progression.

A Higher Dose of Dasatinib May Increase the Possibility of Crossing the Blood-brain Barrier in the Treatment of Patients With Philadelphia Chromosome-positive Acute Lymphoblastic Leukemia.

PURPOSE: Dasatinib is a second-generation tyrosine kinase inhibitor with higher central nervous system (CNS) penetration compared with imatinib and nilotinib in in vitro studies. However, limited clinical data are available regarding the dosage and CNS penetration of dasatinib. The purpose of this study was to investigate the actual ability of dasatinib to cross the blood-brain barrier in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL). METHODS: Plasma and cerebrospinal fluid (CSF) samples collected from Ph+ ALL patients treated with dasatinib were analyzed by using an LC-MS/MS assay. FINDINGS: Orally administered dasatinib 100 mg once daily was well absorbed by the patient but penetrated poorly into the CSF. The use of a higher drug dosage (140 mg/d) may increase systemic drug exposure and enhance the penetration of dasatinib into the CSF. IMPLICATIONS: Based on this study, the use of a higher dosage of dasatinib (140 mg/d) is recommended in patients at high risk of CNS relapse or patients who need treatment for CNS leukemia. ClinicalTrials.gov identifier: NCT02523976.

Gene Deletions and Prognostic Values in B-Linage Acute Lymphoblastic Leukemia.

Although pediatric-like treatment regimen has remarkably improved the survival rates of adults with acute lymphoblastic leukemia (ALL), the outcome of some adult patients is still poor owing to adverse genetic features. These molecular abnormalities, especially gene deletions, may be considered for the prognosis assessment for adult patients with ALL. In this study, using multiplex ligation-dependent probe amplification (MLPA) method, gene deletions were analyzed in from 211 adult B-ALL patients treated in our center. The data showed that 68.2% (144/211) adult B-ALL patients carried gene deletions, and the frequency is much higher in Ph+B-ALL patients. IKZF1 gene deletion is the most common gene deletion in adult B-ALL, followed by CDKN2A/B deletion. In Ph-B-ALL patients, the overall survival of patients with gene deletions is inferior to that of patients without any gene deletions. More obviously, patients with IKZF1 or CDKN2A/B deletion had a worse prognosis, whereas, allogeneic hematopoietic stem cell transplantation could improve OS in patients with IKZF1 deletion, but not in patients with CDKN2A/B deletion. Moreover, the outcome of Ph-B-ALL patients with double deletion of IKZF1and CDKN2A/B may be much worse than that of patients with IKZF1 or CDKN2A/B alone. Minimal residual disease (MRD) was also analyzed together with gene deletions and demonstrated that gene deletions have a negative impact on survival only in MRD positive Ph-B-ALL patients. In conclusion, gene deletions are closely related with the prognosis of adult Ph-B-ALL patients.

Optimized clinical application of minimal residual disease in acute myeloid leukemia with RUNX1-RUNX1T1.

Minimal residual disease (MRD) levels monitored by polymerase chain reaction are associated with outcomes in acute myeloid leukemia with RUNX1-RUNX1T1. The objectives of our study were to quantitatively compare the predictive value of MRD reduction and absolute copies and assess the influence of other prognostic factors on MRD. A total of 224 consecutive patients with RUNX1-RUNX1T1 aged ≤55 years were included in the MRD study. Patients received different induction regimens including conventional- or intermediate-dose cytarabine plus low-dose daunorubicin and omacetaxine mepesuccinate or daunorubicin at 60 mg/m2/day on days 1-3. As continuous variables, both MRD reduction and absolute MRD level were significantly associated with cumulative incidence of relapse (CIR; hazard ratio [HR] = 1.610, 95% confidence interval [CI]: 1.370-1.890, p < 0.001, and HR = 1.170, 95% CI: 1.120-1.230, p < 0.001, respectively). For the CIR, the area under the curves (AUCs) of MRD reduction and absolute MRD level after the first consolidation chemotherapy were 0.629 and 0.629, respectively. Intermediate-dose cytarabine induction (HR = 0.494; p = 0.039 for CIR, HR, 0.451; p = 0.014 for RFS, and HR, 0.262; p = 0.006 for OS) remained significantly associated with outcomes after adjusting for MRD reduction after the first consolidation therapy (HR = 1.456, p < 0.001, for CIR; HR = 1.467, p = 0.001, for relapse-free survival; and HR = 1.468, p = 0.014, for overall survival) in multivariate analyses. In conclusion, the prognostic significance of MRD after the first consolidation therapy was influenced by the induction regimen in acute myeloid leukemia with RUNX1-RUNX1T1.

Adjuvant ruxolitinib therapy relieves steroid-refractory cytokine-release syndrome without impairing chimeric antigen receptor-modified T-cell function.

Aim: Although numerous pro-inflammatory cytokines promote signaling via intracellular pathways involving Janus kinases, it remains unclear if ruxolitinib, a Janus kinase1/2 inhibitor, provides control of cytokine-release syndrome (CRS) without toxicity against therapeutic T cells. Materials & methods: We report successful clinical experience using ruxolitinib as adjuvant therapy to treat steroid-refractory CRS, which was related to CD22/CD19 chimeric antigen receptor-modified T cell sequential infusion, in a patient with Philadelphia chromosome-like acute lymphoblastic leukemia. Results: His symptoms improved rapidly after first dose of ruxolitinib; this was associated with reduced levels of circulating pro-inflammatory indicators. He eventually achieved minimal residual disease negative remission. Discussion: This is the first case in which ruxolitinib was used to treat steroid-refractory CRS; furthermore, this intervention had no apparent impact on the antileukemic actions of the chimeric antigen receptor-modified T cells. Our results suggest that adjuvant ruxolitinib therapy may be an alternative therapeutic approach for the management of CRS.

Randomized Trial of Intermediate-dose Cytarabine in Induction and Consolidation Therapy in Adults with Acute Myeloid Leukemia.

PURPOSE: Cytarabine, 100-200 mg/mE+2/day, is commonly used in induction therapy of acute myelogenous leukemia (AML). Whether a higher dose of cytarabine would be more effective is unknown. Also, there is controversy whether high-dose cytarabine is better than an intermediate-dose combined with other drugs for post-remission therapy. In this open-label, randomized controlled, parallel group study, roles of intermediate-dose cytarabine were investigated. PATIENTS AND METHODS: Subjects with AML age 15-55 years were randomized to receive daunorubicin, omacetaxine mepesuccinate, and conventional- or intermediate-dose cytarabine. Subjects achieving complete remission were randomized to receive 3 courses of high-dose cytarabine or 2 courses of intermediate-dose cytarabine with daunorubicin in the 1st and mitoxantrone in the 2nd course. The primary endpoint was disease-free survival (DFS). RESULTS: 591 subjects were randomized to intermediate- (N = 295) or conventional-dose (N = 296) cytarabine group. Three-year DFSs were 67% [95% confidence interval (CI), 61-73] in the intermediate-dose cohort compared with 54% (95% CI, 48-61) in the conventional-dose cohort [Hazard Ratio (HR), 0.67; 95%CI, 0.51-0.89; P = 0.005). Three-year survivals were 68% (95%CI, 63-74) and 59% (95%CI, 53-65; HR, 0.720; 95%CI, 0.56-0.94; P = 0.014). Two courses of intermediate-dose cytarabine with daunorubicin or mitoxantrone resulted in similar DFS and survival as three courses of high-dose cytarabine when used for post-remission therapy. CONCLUSIONS: Induction therapy with intermediate-dose cytarabine with daunorubicin and omacetaxine mepesuccinate increases DFS and survival in persons with AML ages 15-55 years compared with conventional-dose cytarabine.See related commentary by Watts and Bradley, p. 3073.

[Efficacy of Arsenic Trioxide Combined with ATRA and Chemotherapy for Relapsed Acute Promyelocytic Leukemia Patients].

OBJECTIVE: To investigate the efficacy and safety of arsenic trioxide combined with ATRA and chemo- therapy for treatment of relapsed acute promyelocytic leukemia (APL) patients. METHODS: The clinic data of 25 patients with relapse APL treated in our hospital from 1996 to 2013 were collected and analyzed. Among the 25 patients, 15 patients suffered first-time hematological relapse (HR), and the other 10 patients showed first-time molecular relapse (MR). The patients with first-time replase were treated with ATO+ATRA+Anthracycline re-induction chemotherapy. The clinical features, complete remission (CR) rate, overall survival (OS), disease-free survival (DFS) and adverse events after re-induction therapy were analyzed. RESULTS: Fourteen of 15 hematological relapsed patients achieved the second-time hematological complete remission (CR2) after re-induction therapy except one patient died of bleeding complication during the re-induction. 8 of 14 patient showed molecular complete remission (CRm) after two cycles of therapy with this regimen. Totally, eleven out of the 14 HR patients were alive without disease till the last follow-up, and 3 of the 14 HR patients died because of bleeding complications. All of the 10 molecular relapsed patients received the second CRm after treated by the regimen. Among these 10 patients, 6 patients suffered only once relapse and continued with the molecular CR2 status, and for the other 4 patients with more than two-relapses, only 1 survived untill 89.3 months after achieved second-time CRm, and other 3 patients died because of bleeding complications. CONCLUSION: For relapsed APL patients, the treatment with ATO+ATRA+chemotherapy regimen after relapse still shows encouraging efficacy, no matter whether or not the application of ATO in the previous regimens. In addition, patients with more than two molecular relapses show a poor prognosis.