Incidence and survival of T-cell acute lymphoblastic leukemia in the United States

The efficacy and safety of nelarabine in relapsed or refractory T-cell acute lymphoblastic leukemia: a systematic review and meta-analysis

T-cell Acute Lymphoblastic Leukemia (T-ALL) is a subtype of acute lymphoblastic leukemia characterized by the proliferation of abnormal T-cell precursors. Nelarabine, a purine analog, has been approved as a targeted therapy for patients with refractory or relapsed T-ALL. This study aims to evaluate the efficacy and safety of Nelarabine, either as monotherapy or in combination with other therapies, in treating T-ALL. A systematic review and meta-analysis were conducted following PRISMA guidelines. We searched Cochrane CENTRAL, PubMed, and Google Scholar up to August 2024 for studies evaluating Nelarabine's efficacy and safety in T-ALL patients. The primary outcome was complete response (CR), with secondary outcomes focusing on adverse events (AEs). Data were analyzed using a random effects model, with statistical significance set at p ≤ 0.05. Sixteen studies involving 1,865 patients were included, with 1,345 receiving Nelarabine. The pooled analysis revealed a CR rate of 37.9% (95% CI: 20.5-55.4%, p < 0.001) for Nelarabine monotherapy. Significant adverse events included neutropenia at 29.1% (95% CI: 9.1-49.1%, p < 0.001), thrombocytopenia at 32.4% (95% CI: 14.8-50.0%, p < 0.001), peripheral motor neuropathy at 17.1% (95% CI: 4.2-30.1%, p = 0.001), and peripheral sensory neuropathy at 15.3% (95% CI: 5.8-24.9%, p = 0.003). For combination therapy, infections occurred in 65.0% (95% CI: 27.1-103.0%, p < 0.001) of patients, febrile neutropenia in 48.7% (95% CI: -8.8-106.3%, p < 0.001), peripheral motor neuropathy in 10.5% (95% CI: 7.9-13.0%, p < 0.001), and peripheral sensory neuropathy in 23.1% (95% CI: 10.6-35.7%, p < 0.001). Nelarabine shows significant efficacy in treating refractory or relapsed T-ALL, with notable CR rates. However, its use, both as monotherapy and in combination therapy, is associated with considerable adverse events, particularly neurotoxicity and hematologic toxicities, necessitating careful monitoring. Further research is needed to optimize its application across diverse patient populations and to better manage its associated toxicities.

Notch Inhibitors and BH3 Mimetics in T-Cell Acute Lymphoblastic Leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy with poor response to conventional therapy, derived from hematopoietic progenitors committed to T-cell lineage. Relapsed/Refractory patients account for nearly 20% of childhood and 45% of adult cases. Aberrant Notch signaling plays a critical role in T-ALL pathogenesis and therapy resistance. Notch inhibition is a promising therapeutic target for personalized medicine, and a variety of strategies to prevent Notch activation, including γ-secretase (GS) inhibitors (GSIs) and antibodies neutralizing Notch receptors or ligands, have been developed. Disruption of apoptosis is pivotal in cancer development and progression. Different reports evidenced the interplay between Notch and the anti-apoptotic Bcl-2 family proteins in T-ALL. Although based on early research data, this review discusses recent advances in directly targeting Notch receptors and the use of validated BH3 mimetics for the treatment of T-ALL and their combined action in light of current evidence of their use.

Clinicopathologic features and outcomes of acute leukemia harboring PICALM::MLLT10 fusion

The PICALM::MLLT10 fusion is a rare but recurrent cytogenetic abnormality in acute leukemia, with limited clinicopathologic and outcome data available. Herein, we analyzed 156 acute leukemia patients with PICALM::MLLT10 fusion, including 12 patients from our institutions and 144 patients from the literature. The PICALM::MLLT10 fusion preferentially manifested in pediatric and young adult patients, with a median age of 24 years. T-lymphoblastic leukemia/lymphoma (T-ALL) constituted 65% of cases, acute myeloid leukemia (AML) 27%, and acute leukemia of ambiguous lineage (ALAL) 8%. About half of T-ALL were classified as an early T-precursor (ETP)-ALL. In our institutions' cohort, mediastinum was the most common extramedullary site of involvement. Eight of 12 patients were diagnosed with T-ALL exhibiting a pro-/pre-T stage phenotype (CD4/CD8-double negative, CD7-positive), and frequent CD79a expression. NGS revealed pathogenic mutations in 5 of 6 tested cases, including NOTCH1, and genes in RAS and JAK-STAT pathways and epigenetic modifiers. Of 138 cases with follow-up, pediatric patients (<18 years) had 5-year overall survival (OS) of 71%, significantly better than adults at 33%. The 5-year OS for AML patients was 25%, notably shorter than T-ALL patients at 54%; this distinction was observed in both pediatric and adult populations. Furthermore, adult but not pediatric ETP-ALL patients demonstrated inferior survival compared to non-ETP-ALL patients. Neither karyotype complexity nor transplant status had a discernible impact on OS. In conclusion, PICALM::MLLT10 fusion is most commonly seen in T-ALL patients, particularly those with an ETP phenotype. AML and adult ETP-ALL patients had adverse prognosis. PICALM::MLTT10 fusion testing should be considered in T-ALL, AML, and ALAL patients.

Adult-Onset T-Cell Acute Lymphoblastic Lymphoma-Leukemia Presenting With Petechial Rash: A Case Report

T-cell acute lymphoblastic lymphoma-leukemia (T-ALL) is a rare neoplastic disease with presenting symptoms that are often non-specific. As such, accurate diagnosis requires high clinical suspicion and assessment of bone marrow aspirate with flow cytometry and morphology. While remission is achievable in most patients, the five-year survival rate is only 48% despite treatment. The standard chemotherapy regimen is referred to as hyper-CVAD, where CVAD stands for cyclophosphamide, vincristine sulfate, Adriamycin (doxorubicin), methotrexate, and dexamethasone. In this study, we describe a 38-year-old female who presented with atraumatic abdominal bruising and a petechial rash on the upper and lower extremities. Imaging revealed a 16 cm anterior mediastinal mass and a bone marrow and mediastinal mass biopsy confirmed a diagnosis of T-ALL. The patient received hyper-CVAD cycle 1A with several complications but ultimately achieved remission after four cycles. Here, we stress the importance of broadening differentials for new-onset petechial rashes in adults to include systematic lymphomas, such as T-ALL, and the need for early recognition so patients can receive timely treatment.

Chidamide combined with a modified Bu-Cy conditioning regimen improves survival in patients with T-cell acute lymphoblastic leukemia/lymphoma undergoing allogeneic hematopoietic stem cell transplantation

This study aimed to evaluate the efficacy and safety of chidamide (Chi) combined with a modified Busulfan-Cyclophosphamide (mBuCy) conditioning regimen for T-cell acute lymphoblastic leukemia/lymphoma (T-ALL/LBL) patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Twenty-two patients received chidamide combined with mBuCy conditioning regimen (Chi group). A matched-pair control (CON) group of 44 patients (matched 1:2) received mBuCy only in the same period. The leukemia-free survival (LFS), overall survival (OS), cumulative incidence of relapse (CIR), and non-relapse-related mortality (NRM) were evaluated. Patients in the Chi group were associated with lower 2-year CIR (19.0 vs. 41.4%, P = 0.030), better 2-year LFS (76.1 vs. 48.1%, P = 0.014), and had no significant difference in 2-year OS (80.5 vs. 66.4%, P = 0.088). Patients with minimal residual disease (MRD) positive before HSCT in the Chi group exhibited an advantage in 2-year LFS and a trend towards better 2-year OS (75.0 vs. 10.2%, P = 0.048; 75.0 vs. 11.4%, P = 0.060, respectively). Multivariable analysis showed that the chidamide intensified regimen was independently associated with better LFS (HR 0.23; 95%CI, 0.08-0.63; P = 0.004), and showed no significant impact with OS for all patients (HR 0.34, 95%CI, 0.11-1.07; P = 0.064). The cumulative incidence rates of grade II-IV aGVHD were similar (36.4 vs. 38.6%, P = 0.858). 20 patients in Chi group evinced an elevation in γ-glutamyltransferase, as compared to the mBuCy group (90.9 vs. 65.9%, P = 0.029). No transplantation-related mortality was documented within the first 100 days after transplantation. The results demonstrate that the chidamide intensified regimen may be an effective and acceptable safety option for T-ALL/LBL undergoing allo-HSCT, and further validation is needed.

Nelarabine: when and how to use in the treatment of T-cell acute lymphoblastic leukemia

ABSTRACT

T-cell acute lymphoblastic leukemia or lymphoblastic lymphoma (T-ALL/LBL) is a rare hematologic malignancy most commonly affecting adolescent and young adult males. Outcomes are dismal for patients who relapse, thus, improvement in treatment is needed. Nelarabine, a prodrug of the deoxyguanosine analog 9-β-arabinofuranosylguanine, is uniquely toxic to T lymphoblasts, compared with B lymphoblasts and normal lymphocytes, and has been developed for the treatment of T-ALL/LBL. Based on phase 1 and 2 trials in children and adults, single-agent nelarabine is approved for treatment of patients with relapsed or refractory T-ALL/LBL, with the major adverse effect being central and peripheral neurotoxicity. Since its approval in 2005, nelarabine has been studied in combination with other chemotherapy agents for relapsed disease and is also being studied as a component of initial treatment in pediatric and adult patients. Here, we review current data on nelarabine and present our approach to the use of nelarabine in the treatment of patients with T-ALL/LBL.

Diagnostic and therapeutic advances in adults with acute lymphoblastic leukemia in the era of gene analysis and targeted immunotherapy

Acute lymphoblastic leukemia (ALL) is one of the most rapidly changing hematological malignancies with advanced understanding of the genetic landscape, detection methods of minimal residual disease (MRD), and the development of immunotherapeutic agents with good clinical outcomes. The annual incidence of adult ALL in Korea is 300-350 patients per year. The WHO classification of ALL was revised in 2022 to reflect the molecular cytogenetic features and suggest new adverse- risk subgroups, such as Ph-like ALL and ETP-ALL. We continue to use traditional adverse-risk features and cytogenetics, with MRD-directed post-remission therapy including allogeneic hematopoietic cell transplantation. However, with the introduction of novel agents, such as ponatinib, blinatumomab, and inotuzumab ozogamicin incorporated into frontline therapy, good MRD responses have been achieved, and overall survival outcomes are improving. Accordingly, some clinical trials have suggested a possible era of chemotherapy-free or transplantation-free approaches in the near future. Nevertheless, relapse of refractory ALL still occurs, and some poor ALL subtypes, such as Ph-like ALL and ETP-ALL, are unsolved problems for which novel agents and treatment strategies are needed. In this review, we summarize the currently applied diagnostic and therapeutic practices in the era of advanced genetic analysis and targeted immunotherapies in United States and Europe and introduce real-world Korean data.

IDH2-mutated near ETP-ALL with aggressive leukemia cutis and brisk response to venetoclax and decitabine

Near early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is a rare hematologic malignancy, for which second line therapeutic options are limited. T-cell leukemias are also rarely associated with leukemia cutis, which is more often seen in leukemias of myeloid origin. We present the case of an adult male diagnosed with near ETP-ALL, with IDH2 and DNMT3A mutations, suggestive of a myeloid origin, and leukemia cutis. After the patient progressed on hyper-CVAD and nelarabine, we treated him with the BCL-2 inhibitor venetoclax and the hypomethylating agent decitabine. The regimen induced a rapid bone marrow response and resolution of the leukemia cutis.

Idasanutlin and navitoclax induce synergistic apoptotic cell death in T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignancy in which activating mutations in the Notch pathway are thought to contribute to transformation, in part, by activating c-Myc. Increased c-Myc expression induces oncogenic stress that can trigger apoptosis through the MDM2-p53 tumor suppressor pathway. Since the great majority of T-ALL cases carry inactivating mutations upstream in this pathway but maintain wildtype MDM2 and TP53, we hypothesized that T-ALL would be selectively sensitive to MDM2 inhibition. Treatment with idasanutlin, an MDM2 inhibitor, induced only modest apoptosis in T-ALL cells but upregulated the pro-apoptotic BH3 domain genes BAX and BBC3, prompting us to evaluate the combination of idasanutlin with BH3 mimetics. Combination treatment with idasanutlin and navitoclax, a potent Bcl-2/Bcl-xL inhibitor, induces more consistent and potent synergistic killing of T-ALL PDX lines in vitro than venetoclax, a Bcl-2 specific inhibitor. Moreover, a marked synergic response to combination treatment with idasanutlin and navitoclax was seen in vivo in all four T-ALL xenografts tested, with a significant increase in overall survival in the combination treatment group. Collectively, these preclinical data show that the combination of idasanutlin and navitoclax is highly active in T-ALL and may merit consideration in the clinical setting.

Updates on lymphoblastic leukemia/lymphoma classification and minimal/measurable residual disease analysis

Lymphoblastic leukemia/lymphoma (ALL/LBL), especially certain subtypes, continues to confer morbidity and mortality despite significant therapeutic advances. The pathologic classification of ALL/LBL, especially that of B-ALL, has recently substantially expanded with the identification of several distinct and prognostically important genetic drivers. These discoveries are reflected in both current classification systems, the World Health Organization (WHO) 5th edition and the new International Consensus Classification (ICC). In this article, novel subtypes of B-ALL are reviewed, including DUX4, MEF2D and ZNF384-rearranged B-ALL; the rare pediatric entity B-ALL with TLF3::HLF, now added to the classifications, is discussed; updates to the category of B-ALL with BCR::ABL1-like features (Ph-like B-ALL) are summarized; and emerging genetic subtypes of T-ALL are presented. The second half of the article details current approaches to minimal/measurable residual disease (MRD) detection in B-ALL and T-ALL and presents anticipated challenges to current approaches in the burgeoning era of antigen-directed immunotherapy.

Early T-Cell Precursor Leukemia: A High-Risk Subtype of Acute Lymphoblastic Leukemia, Single Center Experience in Jordan

BACKGROUND AND OBJECTIVES

Early T-cell precursor (ETP) acute lymphoblastic leukemia/lymphoma (ALL/LBL) is a newly recognized entity of T-lymphoblastic leukemia/lymphoma. The optimal therapeutic approaches to adult patients are poorly studied.

PATIENTS AND METHODS

We compared the outcomes of adult's patents with ETP-ALL/LBL who received frontline chemotherapy regimens with other T-ALL/LBL immunophenotypic subtypes. Patients with ETP-ALL/LBL were identified based on CD1a (-), CD8 (-), CD5 (-) (dim), and positivity for 1 or more stem cell or myeloid antigens.

RESULTS

Sixty-nine patients were included between the years 2010 and 2021 (19 ETP-T-ALL/LBL; 50 non ETP- T-cell ALL/LBL). The median age was 26 year (IQR: 21, 33). Fifty-six patients presented as ALL, while 16 with lymphoblastic lymphoma. Forty-seven patients achieved complete remission, and 43 were alive at last encounter. The complete remission rate in patients with ETP-ALL/LBL was lower than that of non-ETP-ALL/LBL patients (32% vs. 68%; P = .2), and the MRD at end of induction was significantly higher (26% vs. 6.2%, P < .001), and more likely to receive allo-SCT consolidation in CR1 (95% vs. 40%, P < .001). After a median follow-up of survivors of 48 months (range: 32-74 months), the median overall survival for patients with ETP-ALL/LBL was not reached versus 11.5 months for the non-ETP-ALL/LBL patients (P = .014)). Twenty-six patients receive allo-SCT in CR1. There was no significant difference in overall survival (79% vs. 70%; P = .49) between both transplant-cohorts in both groups.

CONCLUSION

ETP-ALL/LBL represents a high-risk disease subtype of adult ALL. Novel treatment strategies are needed to improve treatment outcomes in this patient's population.

A functional role of Ephrin type-B receptor 6 (EPHB6) in T-cell acute lymphoblastic leukemia

T-cell lymphoblastic acute leukemia (T-ALL) is an aggressive blood cancer, characterized by restricted cellular subsets with enriched leukemia initiating cells (LICs). Recently, Ephrin receptors (Eph) were described to be highly expressed in cancer stem cells. Here, using public RNA-Seq datasets of human T-ALL, we reported that EphB6 was the only member within the Eph family overexpressed in over 260 samples. We also found the highest level of EphB6 in a minor cell subpopulation within bulk tumors of patient-derived xenografts, obtained through the injection of primary patient biopsy material into immunocompromised NOD-Scid/IL2Rγc-/- (NSG) mice. Interestingly, this EphB6 positive (EphB6+) subset showed an enriched LIC activity after in vivo transplantation into NSG mice. Additionally, gene expression data at the single-cell level of primary patients' leukemic cells revealed that EphB6 + cells were significantly selected in minimal residual disease up to 30 days from the standard treatments and characterized by high levels of markers related to cell proliferation and poor clinical outcome, such as CCNB1 and KIF20A. Taken together, our data suggest that EphB6 supports LICs' maintenance and progression in T-ALL and, thus, targeting EphB6 + cells could be therapeutically relevant for the treatment of T-ALL patients.

Cytogenetics in the management of T-cell acute lymphoblastic leukemia (T-ALL): Guidelines from the Groupe Francophone de Cytogénétique Hématologique (GFCH)

Molecular analysis is the hallmark of T-cell acute lymphoblastic leukemia (T-ALL) categorization. Several T-ALL sub-groups are well recognized based on the aberrant expression of specific transcription factors. This recently resulted in the implementation of eight provisional T-ALL entities into the novel 2022 International Consensus Classification, albeit not into the updated World Health Organization classification system. Despite this extensive molecular characterization, cytogenetic analysis remains the backbone of T-ALL diagnosis in many countries as chromosome banding analysis and fluorescence in situ hybridization are relatively inexpensive techniques to obtain results of diagnostic, prognostic and therapeutic interest. Here, we provide an overview of recurrent chromosomal abnormalities detectable in T-ALL patients and propose guidelines regarding their detection. By referring in parallel to the more general molecular classification approach, we hope to offer a diagnostic framework useful in a broad clinical genetic setting.

Endothelial cell-leukemia interactions remodel drug responses, uncovering T-ALL vulnerabilities

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive and often incurable disease. To uncover therapeutic vulnerabilities, we first developed T-ALL patient-derived tumor xenografts (PDXs) and exposed PDX cells to a library of 433 clinical-stage compounds in vitro. We identified 39 broadly active drugs with antileukemia activity. Because endothelial cells (ECs) can alter drug responses in T-ALL, we developed an EC/T-ALL coculture system. We found that ECs provide protumorigenic signals and mitigate drug responses in T-ALL PDXs. Whereas ECs broadly rescued several compounds in most models, for some drugs the rescue was restricted to individual PDXs, suggesting unique crosstalk interactions and/or intrinsic tumor features. Mechanistically, cocultured T-ALL cells and ECs underwent bidirectional transcriptomic changes at the single-cell level, highlighting distinct "education signatures." These changes were linked to bidirectional regulation of multiple pathways in T-ALL cells as well as in ECs. Remarkably, in vitro EC-educated T-ALL cells transcriptionally mirrored ex vivo splenic T-ALL at single-cell resolution. Last, 5 effective drugs from the 2 drug screenings were tested in vivo and shown to effectively delay tumor growth and dissemination thus prolonging overall survival. In sum, we developed a T-ALL/EC platform that elucidated leukemia-microenvironment interactions and identified effective compounds and therapeutic vulnerabilities.

Cytogenetic and molecular characteristics and outcomes of adult patients with early T-cell precursor acute lymphoblastic leukemia

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is a recently identified high-risk subgroup of T-cell ALL in children. However, there have been conflicting reports and limited data have been reported in adult patients. We retrospectively analyzed the cytogenetic and molecular characteristics and long-term survival outcomes of adult patients with ETP-ALL versus non-ETP-ALL. We analyzed 58 patients (median age, 35 years [range, 18-76 years]) with newly diagnosed T-cell ALL who received a uniform remission induction and consolidation chemotherapy with suitable samples for genetic analyses. If a donor was available, all patients were recommended allogeneic hematopoietic cell transplantation (allo-HCT) for post-remission therapy. Out of 58 patients, 21 (36.2%) had ETP-ALL. Patients with ETP-ALL were older and had a higher proportion of complex karyotype than non-ETP-ALL. Additionally, more DNMT3A mutations were detected in ETP-ALL, whereas FBXW7 mutations and CDKN2A/CDKN2B deletions were found nearly exclusively in non-ETP-ALL. The overall complete remission (CR) rates were not different between ETP-ALL (95.2%) and non-ETP-ALL (81.1%) and subsequent allo-HCT proceeding rates in CR1 were 61.9% for ETP-ALL and 43.2% for non-ETP-ALL, respectively. The overall prognosis of patients with T-ALL was poor that estimated 5-year overall survival (OS) was 33.3% for ETP-ALL and 29.5% for non-ETP-ALL. In a subgroup analysis of patients treated with allo-HCT in CR1 (n = 29), 5-year OS was 53.8% for ETP-ALL and 55.4% for non-ETP-ALL. Our data showed molecular characteristics of ETP-ALL and non-ETP-ALL and revealed that intensive chemotherapy followed by allo-HCT for post-remission therapy can contribute to preserved survival outcome of adult patients with ETP-ALL.

Optimal approach to T-cell ALL

T-lineage acute lymphoblastic leukemia (T-ALL) is curable for most children and adolescent and young adult patients with contemporary frontline chemotherapy regimens. During the past decade, improved survival rates have resulted from the optimization of frontline chemotherapy regimens, the use of minimal residual disease (MRD) assessment for evaluating a patient's risk for relapse, and the intensification of treatment based on the persistence of MRD. Optimization of initial therapy is critical because relapsed T-ALL after initial intensive chemotherapy is incurable for most adult patients. Current T-ALL salvage chemotherapy regimens are minimally effective, and unlike in B-cell ALL, there are no approved antibody therapies or chimeric antigen receptor T-cell therapies for relapsed disease. Immunotherapy and small-molecule inhibitors are beginning to be tested in relapsed T-ALL and have the potential to advance the treatment. Until effective salvage strategies are discovered, however, intensive frontline therapy is required for cure. In this article I review the current frontline chemotherapy regimens for adult patients with T-ALL, summarize the novel targeted and immune therapeutics currently in early-phase clinical trials, and outline how these therapies are helping to define an optimal approach for T-ALL.

Optimal approach to T-cell ALL

T-lineage acute lymphoblastic leukemia (T-ALL) is curable for most children and adolescent and young adult patients with contemporary frontline chemotherapy regimens. During the past decade, improved survival rates have resulted from the optimization of frontline chemotherapy regimens, the use of minimal residual disease (MRD) assessment for evaluating a patient's risk for relapse, and the intensification of treatment based on the persistence of MRD. Optimization of initial therapy is critical because relapsed T-ALL after initial intensive chemotherapy is incurable for most adult patients. Current T-ALL salvage chemotherapy regimens are minimally effective, and unlike in B-cell ALL, there are no approved antibody therapies or chimeric antigen receptor T-cell therapies for relapsed disease. Immunotherapy and small-molecule inhibitors are beginning to be tested in relapsed T-ALL and have the potential to advance the treatment. Until effective salvage strategies are discovered, however, intensive frontline therapy is required for cure. In this article I review the current frontline chemotherapy regimens for adult patients with T-ALL, summarize the novel targeted and immune therapeutics currently in early-phase clinical trials, and outline how these therapies are helping to define an optimal approach for T-ALL.

Latest Contributions of Genomics to T-Cell Acute Lymphoblastic Leukemia (T-ALL)

As for many neoplasms, initial genetic data about T-cell acute lymphoblastic leukemia (T-ALL) came from the application of cytogenetics. This information helped identify some recurrent chromosomal alterations in T-ALL at the time of diagnosis, although it was difficult to determine their prognostic impact because of their low incidence in the specific T-ALL cohort analyzed. Genetic knowledge accumulated rapidly following the application of genomic techniques, drawing attention to the importance of using high-resolution genetic techniques to detect cryptic aberrations present in T-ALL, which are not usually detected by cytogenetics. We now have a clearer appreciation of the genetic landscape of the different T-ALL subtypes at diagnosis, explaining the particular oncogenetic processes taking place in each T-ALL, and we have begun to understand relapse-specific mechanisms. This review aims to summarize the latest advances in our knowledge of the genome in T-ALL. We highlight areas where the research in this subtype of ALL is progressing with the aim of identifying key questions that need to be answered in the medium-long term if this knowledge is to be applied in clinics.

Pharmacotherapeutic management of T-cell acute lymphoblastic leukemia in adults: an update of the literature

INTRODUCTION

T-cell acute lymphoblastic leukemia (T-ALL) is a rare but potentially life-threatening heterogeneous hematologic malignancy that requires prompt diagnosis and treatment by hematologists. So far, therapeutic advances have been achieved in the management of this disease mainly by adopting pediatric-like regimens, and cure rates are significantly worse than in childhood. In T-ALL, less than 70% of adults achieve long-term survival. The prognosis after relapse is still very poor. Hence, there is urgent need to improve therapy of T-ALL by testing new compounds and combinations for the treatment of this disease.

AREAS COVERED

This review provides a comprehensive update on the most recent treatment approaches in adults with de novo and relapsed/refractory adult T-ALL.

EXPERT OPINION

Intensifying chemotherapy may reduce the incidence of recurrent disease in adult patients, but it has not come without a cost. Novel agents with selective T-ALL activity (e.g. nelarabine) may improve survival in some patient subsets. Due to modern genomic and transcriptomic techniques, various novel potential targets might change the treatment landscape in the next few years and will, hopefully alongside with cellular therapies, augment the therapeutic armamentarium in the near future.

Bilateral nephromegaly due to direct leukemic cell invasion in the initial and relapse phases of T-cell acute lymphoblastic leukaemia: A case report

RATIONALE

T-cell acute lymphoblastic leukemia is a relatively uncommon disorder in adults. Kidneys are not frequently invaded by leukemic cells, and patients with adult ALL showing nephromegaly as an initial presentation are rare.

PATIENT CONCERNS

A 54-year-old man was referred to our institution for mild anemia and thrombocytopenia. Laboratory tests showed bicytopenia with abnormal lymphoid cells in the peripheral blood and mild renal dysfunction.

DIAGNOSIS

Ultrasonography and computed tomography (CT) revealed bilateral enlargement of the kidneys. [18F]-fluorodeoxyglucose positron emission tomography/CT demonstrated a strong increase in metabolic uptake in the bilateral kidneys. A kidney biopsy revealed a leukemia invasion into the parenchyma. Based on the lymphocytic repertoire, the patient's condition was diagnosed as T-cell acute lymphoblastic leukaemia.

INTERVENTIONS

The patient received hyper-cyclophosphamide, vincristine, adriamycin, and dexamethasone and high-dose methotrexate and cytarabine as induction chemotherapy. After his leukemia relapsed, he received nelarabine as a second induction therapy and underwent haploidentical peripheral blood stem cell transplantation.

OUTCOMES

Complete remission (CR) was achieved after chemotherapy. Chemotherapy also improved renal function associated with the normalization of bilateral nephromegaly. Repeated [18F]-fluorodeoxyglucose - positron emission tomography/CT posttreatment showedregression of metabolic uptake in the bilateral kidneys. The patient underwent cord blood transplantation at the first CR, but his leukemia relapsed 9 months later. At relapse, bilateral nephromegaly reappeared. Then, the second induction therapy induced CR for at least 10 months after induction therapy.

LESSONS

Although rare, ALL in the initial and relapsed phases can be associated with bilateral nephromegaly and renal impairment due to the invasion of leukemic cells into the parenchyma with or without abnormal leukemic cells in circulation. Leukemia is an important differential diagnosis of renal impairment with bilateral nephromegaly.

Early T-Cell Precursor Acute Lymphoblastic Leukemia: Diagnosis, Updates in Molecular Pathogenesis, Management, and Novel Therapies

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is a distinct subtype of T lymphoblastic leukemia (T-ALL) identified in 2009, due to its unique immunophenotypic and genomic profile. The outcome of patients was poor in earlier studies, and they were prone to have induction failure, with more frequent relapse/refractory disease. Recent advances had been made in discoveries of genetic aberrations and molecular pathogenesis of ETP-ALL. However, the diagnosis and management of ETP-ALL is still challenging. There are limited choices of novel therapies so far. In this review article, it highlighted the diagnostic issue of ETP-ALL, pitfall in diagnosis, and strategy of accurate diagnosis. The review also summarized current understanding of molecular mechanism of leukemogenesis. The emerging role of risk-adapted therapy and allogenic stem cell transplant in optimizing the outcome of patients with ETP-ALL was discussed. Finally, some potential novel therapies were proposed based on the current understanding of molecular pathogenesis.

Chidamide inhibits the NOTCH1-MYC signaling axis in T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is one of the most dangerous hematological malignancies, with high tumor heterogeneity and poor prognosis. More than 60% of T-ALL patients carry NOTCH1 gene mutations, leading to abnormal expression of downstream target genes and aberrant activation of various signaling pathways. We found that chidamide, an HDAC inhibitor, exerts an antitumor effect on T-ALL cell lines and primary cells including an anti-NOTCH1 activity. In particular, chidamide inhibits the NOTCH1-MYC signaling axis by down-regulating the level of the intracellular form of NOTCH1 (NICD1) as well as MYC, partly through their ubiquitination and degradation by the proteasome pathway. We also report here the preliminary results of our clinical trial supporting that a treatment by chidamide reduces minimal residual disease (MRD) in patients and is well tolerated. Our results highlight the effectiveness and safety of chidamide in the treatment of T-ALL patients, including those with NOTCH1 mutations and open the way to a new therapeutic strategy for these patients.

State-of-Art of Cellular Therapy for Acute Leukemia

With recent clinical breakthroughs, immunotherapy has become the fourth pillar of cancer treatment. Particularly, immune cell-based therapies have been envisioned as a promising treatment option with curative potential for leukemia patients. Hence, an increasing number of preclinical and clinical studies focus on various approaches of immune cell-based therapy for treatment of acute leukemia (AL). However, the use of different immune cell lineages and subsets against different types of leukemia and patient disease statuses challenge the interpretation of the clinical applicability and outcome of immune cell-based therapies. This review aims to provide an overview on recent approaches using various immune cell-based therapies against acute B-, T-, and myeloid leukemias. Further, the apparent limitations observed and potential approaches to overcome these limitations are discussed.

Secular trends in the incidence and survival of all leukemia types in the United States from 1975 to 2017

Background: Various studies have indicated that the prognosis of leukemia has been improved in recent years, but the secular trends of incidence and long-term survival of all leukemia have not been thoroughly examined.

Methods: We estimated the leukemia incidence and 5-year survival rate along with the temporal trends by sex, race, age, and subtype in the United States over the past four decades using Surveillance, Epidemiology, and End Results (SEER) database.

Results: The overall incidence of leukemia steadily increased from 12.39/100 000 in 1975 to 14.65/100 000 in 2011, and then began to decline in recent years (13.73/100 000 in 2017), with average annual percent changes (APC) of 0.350 (P<0.001). The 5-year relative survival rate of leukemia patients significantly improved from 33.2% in 1975 to 66.1% in 2012 (APC=1.980, P<0.001). The main subtypes of leukemia, including acute lymphoblastic leukemia, acute myeloid leukemia, chronic lymphocytic leukemia, and chronic myeloid leukemia, increased in most age groups; conversely, the incidences of all other subtypes were gradually declined during the monitoring period. The incremental advancement in leukemia prognosis had been achieved in almost all histological subtypes, especially among young patients.

Conclusions: Based on SEER data, the leukemia incidence increased gradually over the past decades, and then began to decline in recent years in the United States. The 5-year relative survival rate increased incrementally over time, especially among young patients. However, the huge disparities among different sexes, races, histological subtypes, and age groups, emphasize that precise causes control and innovative treatments need to be developed to reduce the incidence and improve the prognosis, especially among specific populations.

Ring chromosome 7 in a child with T-cell acute lymphoblastic leukemia with myeloid markers

Ring chromosomes are uncommon in hematological diseases. Here we present the case of a 13-year-old girl with leukocytosis, anemia, and lymphadenopathy. Flow cytometry analysis revealed a predominant precursor T lymphoid population expressing CD7, CD5, CD2, and cytoplasmic CD3 with partial expression of CD33, CD34, CD117, and CD11c; TdT was positive, and myeloperoxidase was negative. The bone marrow aspirate showed markedly increased blasts that were positive for CD3, CD7, CD34, TdT, and myeloperoxidase (rare positivity) by immunohistochemistry stain, consistent with T-cell acute lymphoblastic leukemia (T-ALL) extensively involving a hypercellular marrow for age. The karyotype showed a ring 7 in 12 of the 21 metaphase cells examined and deletions of the subtelomeric regions on chromosome 7. Deletions in the short arm of chromosome 7 and the long arm of chromosome 7 are present in 2% to 4% of pediatric T-ALL cases. Ring chromosome 7 is typically seen in myeloid malignancies, including acute myeloid leukemia.

Chimeric Antigen Receptor T Cells Targeting NKG2D-Ligands Show Robust Efficacy Against Acute Myeloid Leukemia and T-Cell Acute Lymphoblastic Leukemia

CAR T cell approaches to effectively target AML and T-ALL without off-tumor effects on healthy myeloid or T cell compartments respectively are an unmet medical need. NKG2D-ligands are a promising target given their absence on healthy cells and surface expression in a wide range of malignancies. NKG2D-ligand expression has been reported in a substantial group of patients with AML along with evidence for prognostic significance. However, reports regarding the prevalence and density of NKG2D-ligand expression in AML vary and detailed studies to define whether low level expression is sufficient to trigger NKG2D-ligand directed CART cell responses are lacking. NKG2D ligand expression in T-ALL has not previously been interrogated. Here we report that NKG2D-ligands are expressed in T-ALL cell lines and primary T-ALL. We confirm that NKG2D-ligands are frequently surface expressed in primary AML, albeit at relatively low levels. Utilizing CAR T cells incorporating the natural immune receptor NKG2D as the antigen binding domain, we demonstrate striking in vitro activity of CAR T cells targeting NKG2D-ligands against AML and T-ALL cell lines and show that even low-level ligand expression in primary AML targets results in robust NKG2D-CAR activity. We found that NKG2D-ligand expression can be selectively enhanced in low-expressing AML cell lines and primary AML blasts via pharmacologic HDAC inhibition. Such pharmacologic NKG2D-ligand induction results in enhanced NKG2D-CAR anti-leukemic activity without affecting healthy PBMC, thereby providing rationale for the combination of HDAC-inhibitors with NKG2D-CAR T cell therapy as a potential strategy to achieve clinical NKG2D-CAR T cell efficacy in AML.

Population-Level Outcomes of Pediatric Acute Promyelocytic Leukemia in the United States

OBJECTIVE

To determine whether the population level outcomes of pediatric acute promyelocytic leukemia have improved over time.

STUDY DESIGN

We conducted a retrospective analysis of the Surveillance Epidemiology and End Results database for patients with acute promyelocytic leukemia, up to 20 years of age, diagnosed between 1976 and 2016 and actively followed. Patients were stratified based on their period of diagnosis (1976-1989, 1990-1999, 2000-2009, 2010-2016) to assess the temporal trends in overall survival and early mortality.

RESULTS

A total of 553 patients with a median age of 15 years (range, 0-20 years) were included. The 5-year overall survival increased significantly over time (by 22.6% from 1976 to 1989; by 59.2% from 1990 to 1999; by 77.7% from 2000 to 2009; and by 88.9% from 2010 to 2016; P < .001). Early mortality showed an improvement over time in the most recent cohort (by 14% from 1976 to 1989; by 13.5% from1990 to 1999; by 13.3% 2000 to 2009; and by 7.2% from 2010 to 2016) after adjusting for other demographic characteristics in a logistic regression model. On multivariate analysis of overall survival, diagnosis in the earlier time periods was associated with higher mortality as compared with the 2010-2016 period. Age, sex, and race/ethnicity were not significant predictors of overall survival.

CONCLUSIONS

Outcomes of pediatric acute promyelocytic leukemia have continued to improve over time at the population level.

Early precursor T-cell acute lymphoblastic leukemia: current paradigms and evolving concepts

Early precursor T cell-acute lymphoblastic leukemia (ETP-ALL) is a rare entity characterized by chemo-resistance and a paucity of data regarding optimal management. We review here the literature regarding the management of ETP-ALL and focus on the recent, emerging data, regarding the potential role of molecularly targeted approaches with a focus on venetoclax.