Characteristics and prognosis analysis of additional chromosome abnormalities in newly diagnosed acute promyelocytic leukemia treated with arsenic trioxide as the front-line therapy

Prognosis influence of additional chromosome abnormalities in newly diagnosed acute promyelocytic leukemia with t(15;17)(q24;q21)

OBJECTIVES

In patients with acute promyelocytic leukemia (APL), additional chromosomal abnormalities (ACAs) are prognostic indicators. However, the clinical features of ACAs were not systematically reported in Chinese patients. Therefore, we enrolled a large cohort of APLs to demonstrate the clinical characteristics and prognostic value of ACAs.

METHODS

268 patients with newly diagnosed APL with t(15;17)(q24;q21) were retrospectively enrolled, and their clinical characteristics and the predictive value of ACAs were assessed between patients with the presence and absence of ACAs.

RESULTS

APL patients with and without ACAs did not differ significantly in their clinical features or treatment response and clinical outcomes like overall survival (OS) and disease-free survival (DFS). It appeared to be substantially associated with worse OS in APL patients with trisomy 8, which was the most common ACA, although DFS was unaffected. Interestingly, the presence of ACAs or trisomy 8 affected OS and DFS in the subgroup of patients aged ≥60 years; by contrast, ACAs had no effect on OS or DFS in any treatment subgroup (ATRA + ATO/RIF or ATRA + ATO/RIF + CH or ATRA + CH), except for the ATRA + ATO/RIF + CH treatment subgroup, where their impact on DFS was less favorable.

CONCLUSIONS

Our results suggested that OS and DFS were unaffected by ACAs. Nonetheless, in the subgroup of patients older than 60, the existence of ACAs or trisomy 8 appeared to impact OS and DFS negatively. Individuals with t(15;17) alone had a higher DFS and were more susceptible to ATRA + ATO/RIF + CH than individuals with t(15;17) ACAs.

Comparison of laboratory characteristics and clinical prognosis of APL with negative and positive PML-RARα gene

This study analyzes the laboratory characteristics and prognosis of patients between PML-RARα negative APL and PML-RARα positive APL and compares the differences in order to improve the understanding of this rare APL and guide clinical diagnosis and treatment. A total of 81 patients with newly diagnosed APL based on bone marrow cell morphology were included, with 14 in the PML-RARα gene negative group and 67 in the PML-RARα gene positive group. The sex, age, peripheral blood routine test, coagulation related indicators, bone marrow cell morphology, flow cytometric immunophenotype, abnormal chromosome expression and prognosis of the 2 groups were analyzed and compared. PML-RARα gene-negative and PML-RARα gene-positive groups were statistically significant in leukocyte count, fibrinogen content, proportion of abnormal promyelocytes, positive rate of Auer bodies, strongly positive peroxidase staining, positive CD13, CD4, CD11b, CD15, CD25 expression and complete response rate during 1 course (P < .05). By the end of follow-up in February 2021, the duration of CR in the PML-RARα gene-negative group was short (P < .05). This study found that the efficacy and prognosis of patients with PML-RARα gene negative were worse than those of the positive group, but the correlation between indicators and prognosis needs to be further explored and confirmed in more diverse samples.

Risk factors and remaining challenges in the treatment of acute promyelocytic leukemia

The treatment of acute promyelocytic leukemia (APL) has evolved with the introduction of all-trans retinoic acid (ATRA) and subsequent arsenic trioxide (ATO), particularly in standard-risk APL with an initial white blood cell count (WBC) < 10,000/μL, where a high cure rate can now be achieved. However, for some patients with risk factors, early death or relapse remains a concern. Insights from the analysis of patients treated with ATRA and chemotherapy have identified risk factors such as WBC, surface antigens, complex karyotypes, FLT3 and other genetic mutations, p73 isoforms, variant rearrangements, and drug resistance mutations. However, in the ATRA + ATO era, the significance of these risk factors is changing. This article provides a comprehensive review of APL risk factors, taking into account the treatment approach, and explores the challenges associated with APL treatments.

Cytogenetics in the management of acute myeloid leukemia and histiocytic/dendritic cell neoplasms: Guidelines from the Groupe Francophone de Cytogénétique Hématologique (GFCH)

Genetic data are becoming increasingly essential in the management of hematological neoplasms as shown by two classifications published in 2022: the 5th edition of the World Health Organization Classification of Hematolymphoid Tumours and the International Consensus Classification of Myeloid Neoplasms and Acute Leukemias. Genetic data are particularly important for acute myeloid leukemias (AMLs) because their boundaries with myelodysplastic neoplasms seem to be gradually blurring. The first objective of this review is to present the latest updates on the most common cytogenetic abnormalities in AMLs while highlighting the pitfalls and difficulties that can be encountered in the event of cryptic or difficult-to-detect karyotype abnormalities. The second objective is to enhance the role of cytogenetics among all the new technologies available in 2023 for the diagnosis and management of AML.

Case Report: Co-existence of a novel EXOC4-TRHDE gene fusion with PML-RARA in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is a type of myeloid leukemia with a specific chromosomal translocation t(15;17)(q22; q12) forming the PML-RARA fusion gene. However, approximately one third of newly diagnosed patients with APL have additional chromosomal abnormalities. Here, we report a case of APL with co-existence of a novel translocation t(7;12)(q32;q13) involving an out-of-frame fusion between EXOC4 and TRHDE, together with PML-RARA. The patient achieved complete remission after treatment with conventional therapy with all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). Although the causative link between EXOC4-TRHDE and PML-RARA has yet to be established, the patient had a good response to therapy, suggesting that the EXOC4-TRHDE fusion does not affect the efficacy of combined treatment with ATRA and ATO.

Effect of Additional Cytogenetic Abnormalities on Survival in Arsenic Trioxide-Treated Acute Promyelocytic Leukemia

Complex karyotype is associated with inferior event-free survival in patients who have acute promyelocytic leukemia treated with ATO.

Frontline arsenic trioxide (ATO)–based treatment regimens achieve high rates of long-term relapse-free survival in treating acute promyelocytic leukemia (APL) and form the current standard of care. Refining prognostic estimates for newly diagnosed patients treated with ATO-containing regimens remains important in continuing to improve outcomes and identify patients who achieve suboptimal outcomes. We performed a pooled analysis of exclusively ATO-treated patients at a single academic institution and from the ALLG APML4 and Alliance C9710 studies to determine the prognostic importance of additional cytogenetic abnormalities and/or complex karyotype. We demonstrated inferior event-free survival for patients harboring complex karyotype (hazard ratio [HR], 3.74; 95% confidence interval [CI], 1.63-8.56; P = .002), but not for patients harboring additional cytogenetic abnormalities (HR, 2.13; 95% CI, 0.78-5.82; P = .142). These data support a role for full karyotypic analysis of all patients with APL and indicate a need for novel treatment strategies to overcome the adverse effect of APL harboring complex karyotype.

Outcome of older (≥70 years) APL patients frontline treated with or without arsenic trioxide-an International Collaborative Study

Data on outcome in older (≥70 years) patients with acute promyelocytic leukemia after treatment with arsenic trioxide (ATO) compared with standard chemotherapy (CTX) is scarce. We evaluated 433 patients (median age, 73.4 years) treated either with ATO+ all-trans retinoic acid (ATO/ATRA; n = 26), CTX/ATRA + ATO during consolidation (CTX/ATRA/ATO; n = 148), or with CTX/ATRA (n = 259). Median follow-up for overall survival (OS) was 4.8 years. Complete remissions (CR) were achieved in 92% with ATO/ATRA and 82% with CTX/ATRA; induction death rates were 8% and 18%, respectively. For analysis of postremission outcomes we combined the ATO/ATRA and CTX/ATRA/ATO groups (ATO/ATRA ± CTX). Cumulative incidence of relapse (CIR) was significantly lower after ATO/ATRA ± CTX compared with CTX/ATRA (P < 0.001). The same held true when restricting the analysis according to the treatment period after the year 2000. OS of patients in CR1 was not different between ATO/ATRA ± CTX compared with CTX/ATRA (P = 0.20). High (>10 × 10⁹/l) white blood cell (WBC) counts at diagnosis were associated with higher CIR (P < 0.001) compared with lower WBC in the CTX/ATRA group, but not in the ATO/ATRA ± CTX group (P = 0.48). ATO, when added to ATRA or CTX/ATRA is feasible and effective in elderly patients for remission induction and consolidation, particularly in patients with high WBC at diagnosis.

[Application of immunophenotypic analysis and molecular genetics in the diagnosis of acute promyelocytic leukemia]

Objective: To investigate the application values of immunophenotypic analysis and molecular genetics in the diagnosis of acute promyelocytic leukemia (APL) . Methods: The retrospective analyses of flow cytometric (FCM) immunophenotypic anyalysis, chromosome karyotype and chromosome fluorescence in situ hybridization (FISH) of 798 outpatient or hospitalization APL patients referred to our hospital between May 2012 and December 2017 were performed to further study the application values of FCM and molecular genetics in the diagnosis of APL. Results: The sensitivity and specificity of FCM were 91.9% and 98.7% respectively. The typical characteristic immunophenotype for APL was as of follows: a high SSC, absence of expression of cluster differntiation (CD) CD34 and HLA-DR, and expression or stronger expression of CD33, consistent expression of CD13, CD9, CD123, expression of CD56, CD7, CD2 (sometimes) . The rest 10% of the cases harbored atypical APL phenotypes, generally accompanied by CD34 and/or HLA-DR expression, decreased SSC and often accompanied by CD2 expression, it was difficult to definitively diagnose APL by this FCM phenotype, and their diagnoses depended on the results of genetics or molecular biology tests. Compared with normal individuals, complex karyotypes APL with t (15;17) translocation, other variant translocations and variant t (11;17) , t (5;17) had no significant differences in terms of their FCM phenotypes. Conclusions: FCM could rapidly and effectively diagnose APL. Despite the fact that complex karyotypes with various additional chromosomal abnormalities were detected in approximately one third of APL cases in addition to the pathognomonic t (15;17) (q22;q21) , they had no observable impact on the overall immunophenotype. Molecular and genetic criteria were the golden criteria for the diagnosis of APL. About 10% of immunophenotyping cases relied on molecular genetics for diagnosis.

Clinical significance of complex karyotype at diagnosis in pediatric and adult patients with de novo acute promyelocytic leukemia treated with ATRA and chemotherapy

Although additional cytogenetic abnormalities (ACA) do not affect the prognosis of patients with t(15;17) acute promyelocytic leukemia (APL), the role of a complex karyotype (CK) is yet to be clarified. We aimed to investigate the relationship of CK with relapse incidence in 1559 consecutive APL patients enrolled in three consecutive trials. Treatment consisted of AIDA induction followed by risk-adapted consolidation. A CK (CK) was defined as the presence of ≥2 ACA, and a very CK (CK+) as ≥3 ACA. Eighty-nine patients (8%) had a CK, of whom 41 (4%) had CK+. The 5-year cumulative incidence of relapse (CIR) in patients with CK was 18%, and 12% in those with <2 ACA (p=.09). Among patients with CK+, the 5-year CIR was 27% vs 12% (p=.003), retaining the statistical significance in multivariate analysis. This study shows an increased risk of relapse among APL patients with CK + treated with ATRA plus chemotherapy front-line regimens.

Clinical implications of molecular markers in acute myeloid leukemia

The recently updated World Health Organization (WHO) Classification of myeloid neoplasms and leukemia reflects the fact that research in the underlying pathogenic mechanisms of acute myeloid leukemia (AML) has led to remarkable advances in our understanding of the disease. Gene mutations now allow us to explore the enormous diversity among cytogenetically defined subsets of AML, particularly the large subset of cytogenetically normal AML. Despite the progress in unraveling the tumor genome, only a small number of recurrent mutations have been incorporated into risk-stratification schemes and have been proven to be clinically relevant, targetable lesions. We here discuss the utility of molecular markers in AML in prognostication and treatment decision making, specifically highlighting the aberrations included in the current WHO classification.

Characteristics and outcome of patients with therapy-related acute promyelocytic leukemia front-line treated with or without arsenic trioxide

Therapy-related acute promyelocytic leukemia (t-APL) is relatively rare, with limited data on outcome after treatment with arsenic trioxide (ATO) compared to standard intensive chemotherapy (CTX). We evaluated 103 adult t-APL patients undergoing treatment with all-trans retinoic acid (ATRA) alone (n=7) or in combination with ATO (n=24), CTX (n=53), or both (n=19). Complete remissions were achieved after induction therapy in 57% with ATRA, 100% with ATO/ATRA, 78% with CTX/ATRA, and 95% with CTX/ATO/ATRA. Early death rates were 43% for ATRA, 0% for ATO/ATRA, 12% for CTX/ATRA and 5% for CTX/ATO/ATRA. Three patients relapsed, two developed therapy-related acute myeloid leukemia and 13 died in remission including seven patients with recurrence of the prior malignancy. Median follow-up for survival was 3.7 years. None of the patients treated with ATRA alone survived beyond one year. Event-free survival was significantly higher after ATO-based therapy (95%, 95% CI, 82-99%) as compared to CTX/ATRA (78%, 95% CI, 64-87%; P=0.042), if deaths due to recurrence of the prior malignancy were censored. The estimated 2-year overall survival in intensively treated patients was 88% (95% CI, 80-93%) without difference according to treatment (P=0.47). ATO when added to ATRA or CTX/ATRA is feasible and leads to better outcomes as compared to CTX/ATRA in t-APL.

Persistent Hypoplastic Acute Promyelocytic Leukemia with a Novel Chromosomal Abnormality of 46, XY, t(15;17), t(9;11)(q13;p13)

A diagnosis of acute promyelocytic leukemia (APL) is usually made when normal hematopoietic cells are substituted by APL cells. We encountered a unique APL patient who presented with persistent hypoplastic features of APL. An 84-year-old man presented with leukopenia (2.2 × 10(9)/L) and anemia (Hb 12.5 g/dL). Five months later, the bone marrow (BM) was hypoplastic with a normal proportion of blasts and promyelocytes (5.2%), although the latter cells were hypergranular. The karyotype of BM cells was 46, XY, t(15;17)(q22;q12), t(9;11)(q13;p13). Two months later, the BM remained hypoplastic with 8.5% hypergranular promyelocytes, some of which contained faggot of Auer rods. RT-PCR examination yielded the PML-RARα transcript, and its sequencing revealed the breakpoint of PML to be bcr2. The patient was treated with all-trans retinoic acid under a diagnosis of APL with improvement of the bicytopenia. FISH analysis of BM cells yielded a negative result regarding t(15;17), although RT-PCR was positive for PML-RARα mRNA. Six months later, APL recurred with the same karyotypic abnormalities and therapeutic resistance, and the patient died of pneumonia. A persistent hypoplastic state of APL may be a rare event, and the association of t(15;17) and t(9;11) is novel.

Use of arsenic trioxide in remission induction and consolidation therapy for acute promyelocytic leukaemia in the Australasian Leukaemia and Lymphoma Group (ALLG) APML4 study: a non-randomised phase 2 trial

BACKGROUND

Initial treatment of acute promyelocytic leukaemia traditionally involves tretinoin (all-trans retinoic acid) combined with anthracycline-based risk-adapted chemotherapy, with arsenic trioxide being the treatment of choice at relapse. To try to reduce the relapse rate, we combined arsenic trioxide with tretinoin and idarubicin in induction therapy, and used arsenic trioxide with tretinoin as consolidation therapy.

METHODS

Patients with previously untreated genetically confirmed acute promyelocytic leukaemia were eligible for this study. Eligibilty also required Eastern Cooperative Oncology Group performance status 0-3, age older than 1 year, normal left ventricular ejection fraction, Q-Tc interval less than 500 ms, absence of serious comorbidity, and written informed consent. Patients with genetic variants of acute promyelocytic leukaemia (fusion of genes other than PML with RARA) were ineligible. Induction comprised 45 mg/m(2) oral tretinoin in four divided doses daily on days 1-36, 6-12 mg/m(2) intravenous idarubicin on days 2, 4, 6, and 8, adjusted for age, and 0·15 mg/kg intravenous arsenic trioxide once daily on days 9-36. Supportive therapy included blood products for protocol-specified haemostatic targets, and 1 mg/kg prednisone daily as prophylaxis against differentiation syndrome. Two consolidation cycles with tretinoin and arsenic trioxide were followed by maintenance therapy with oral tretinoin, 6-mercaptopurine, and methotrexate for 2 years. The primary endpoints of the study were freedom from relapse and early death (within 36 days of treatment start) and we assessed improvement compared with the 2 year interim results. To assess durability of remission we compared the primary endpoints and disease-free and overall survival at 5 years in APML4 with the 2 year interim APML4 data and the APML3 treatment protocol that excluded arsenic trioxide. This study is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12605000070639.

FINDINGS

124 patients were enrolled between Nov 10, 2004, and Sept 23, 2009, with data cutoff of March 15, 2012. Four (3%) patients died early. After a median follow-up of 4·2 years (IQR, 3·2-5·2), the 5 year freedom from relapse was 95% (95% CI 89-98), disease-free survival was 95% (89-98), event-free survival was 90% (83-94), and overall survival was 94% (89-97). The comparison with APML3 data showed that hazard ratios were 0·23 (95% CI 0·08-0·64, p=0·002) for freedom from relapse, 0·21 (0·07-0·59, p=0·001) for disease-free survival, 0·34 (0·16-0·69, p=0·002) for event-free survival, and 0·35 (0·14-0·91, p=0·02) for overall survival.

INTERPRETATION

Incorporation of arsenic trioxide in initial therapy induction and consolidation for acute promyelocytic leukaemia reduced the risk of relapse when compared with historical controls. This improvement, together with a non-significant reduction in early deaths and absence of deaths in remission, translated into better event-free and overall survival.

FUNDING

Phebra.

Immunophenotypes and immune markers associated with acute promyelocytic leukemia prognosis

CD2+, CD34+, and CD56+ immunophenotypes are associated with poor prognoses of acute promyelocytic leukemia (APL). The present study aimed to explore the role of APL immunophenotypes and immune markers as prognostic predictors on clinical outcomes. A total of 132 patients with de novo APL were retrospectively analyzed. Immunophenotypes were determined by flow cytometry. Clinical features, complete remission (CR), relapse, and five-year overall survival (OS) rate were assessed and subjected to multivariate analyses. The CD13+CD33+HLA-DR-CD34− immunophenotype was commonly observed in patients with APL. Positive rates for other APL immune markers including cMPO, CD117, CD64, and CD9 were 68.7%, 26%, 78.4%, and 96.6%, respectively. When compared with patients with CD2− APL, patients with CD2+ APL had a significantly higher incidence of early death (50% versus 15.7%; P = 0.016), lower CR rate (50% versus 91.1%; P = 0.042), and lower five-year OS rate (41.7% versus 74.2%; P = 0.018). White blood cell (WBC) count before treatment was found to be the only independent risk factor of early death, CR failure, and five-year mortality rate. Flow cytometric immunophenotype analysis can facilitate prompt APL diagnosis. Multivariate analysis has demonstrated that WBC count before treatment is the only known independent risk factor that predicts prognosis for APL in this study population.