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

Long-term exposure and response to azacitidine for post-hematopoietic stem cell transplantation relapse of early T-cell precursor acute lymphoblastic leukemia: a case report and review of the literature

Adult T-cell acute lymphoblastic leukemia has a poor outcome after relapse. Because the subtype of early T-cell precursor displays characteristics close of those of acute myeloid leukemia, such as epigenetic dysregulation, hypomethylating agents might prove of interest. We describe the case of a patient relapsing 3 months only after allogeneic stem cell transplantation who achieved complete remission on azacitidine, and is still on therapy 9 years later. We discuss the biological background of this very long-term response, underlining the immunological effects of hypomethylating agents, and the perspectives opened by combination of hypomethylating agents with other drugs such as venetoclax.

Synergistic Effect of Venetoclax and Bendamustine in Early T-cell Precursor Acute Lymphoblastic Leukemia

BACKGROUND/AIM

To date, therapeutic options for T-cell acute lymphoblastic leukemia (T-ALL) remain very limited. This study evaluated the efficacy of monotherapies and combination therapies including a selective BCL-2 inhibitor for T-ALL cell lines, namely Jurkat, CCRF-CEM, and Loucy.

MATERIALS AND METHODS

Loucy is an early T-precursor ALL (ETP-ALL) cell line characterized by an immature phenotype, whereas Jurkat and CCRF-CEM are late T-cell progenitor ALL (LTP-ALL) cell lines. Monotherapy was conducted with venetoclax, cytarabine, bendamustine, or azacytidine, whereas combination therapy was performed with venetoclax plus cytarabine, venetoclax plus bendamustine, or venetoclax plus azacytidine. Cell viability assay was conducted after 48 h using Trypan blue and the 3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS). Statistical analysis for evaluating synergistic interactions between anticancer drugs was performed by using the SynergyFinder Plus and drc R package.

RESULTS

Adding venetoclax to cytarabine, bendamustine, or azacitidine achieved an additive effect, with Loewe synergic scores ranging from -10 to 10 in Jurkat and CCRF-CEM. Conversely, the combination of venetoclax and cytarabine displayed an additive effect (Loewe synergic score: 8.45 and 5.82 with MTS and Trypan blue assays, respectively), whereas venetoclax plus bendamustine or azacitidine exhibited a synergistic effect (Loewe synergic score >10 with MTS assay) in Loucy. Remarkably, the Bliss/Loewe score revealed that the combination of venetoclax and bendamustine was the most synergistic, yielding a score of 13.832±0.55.

CONCLUSION

The combination of venetoclax and bendamustine demonstrated the greatest synergistic effect in suppressing ETP-ALL cell proliferation. Further studies are warranted to determine the mechanisms for the synergism between venetoclax and bendamustine in high-risk T-ALL.

[Clinical efficacy and safety of venetoclax combined with multidrug chemotherapy in the treatment of 15 patients with relapsed or refractory early T-cell precursor acute lymphoblastic leukemia]

Objective: To explore the efficacy and safety of Venetoclax combined with multidrug chemotherapy in patients with relapsed or refractory early T-cell precursor acute lymphoblastic leukemia (R/R ETP-ALL) . Methods: This study retrospectively analyzed 15 patients with R/R ETP-ALL who received Venetoclax combined with multidrug chemotherapy from December 2018 to February 2022. Among them, eight cases were combined with demethylated drugs, four cases were combined with demethylated drugs and HAAG chemotherapy regimen, two cases were combined with demethylated drugs and CAG regimen, and one case was combined with Cladribine. Specific usage and dosage of Venetoclax: 100 mg on day 1, 200 mg on day 2, 400 mg on day 3-28, orally; when combined with azole antifungal drugs, dosage was reduced to 100 mg/d. Results: Fifteen patients (10 males and 5 females) with R/R ETP-ALL were treated with Venetoclax and multidrug chemotherapy with a median age of 35 (12-42) years old. Of 4 refractory and 11 relapsed patients, the efficacy was evaluated on the 21th day following combined chemotherapy: the overall response rate, the complete response (CR) rate, and the CR with incomplete hematological recovery (CRi) rate were 67.7% (10/15), 60.0% (9/15), and 6.7% (1/15), respectively. For the overall study population, the 12-month overall survival (OS) rate was 60.0%, and the median OS was 17.7 months. The disease-free survival (DFS) rate of all CR patients at 12 months was 60.0%, and the median DFS did not reach. About 14 patients had Ⅲ-Ⅳ hematological toxicity, but these adverse reactions were all controllable. No adverse reaction in the nervous system and tumor lysis syndrome occurred in this study, and no adverse reaction of organs above grade Ⅲ occurred. Conclusion: Venetoclax combined with multidrug chemotherapy may be a safe and promising treatment option for patients with R/R ETP-ALL.

Short-course Venetoclax With Standard Chemotherapy Is Effective in Early T-cell Precursor Acute Lymphoblastic Leukemia

BACKGROUND

Early T-cell precursor acute lymphoblastic leukemia (ETP ALL) is a high-risk subgroup of acute lymphoblastic leukemia characterized by unique immune phenotype and disease biology. ETP ALL cells share similarities with hematopoietic stem cells and myeloid progenitor cells. These patients have lower rates of complete remission and overall survival. High BCL2 expression is the main rationale for using venetoclax in ETP ALL.

RESULTS

We report the treatment outcomes of 2 patients with ETP ALL who achieved minimal residual disease negative remission with the short course of venetoclax.

CONCLUSIONS

Combination therapy of short-course venetoclax with Berlin-Frankfurt-Meunster 95 regimen is an effective regimen for treating patients with ETP ALL.

In Silico Integration of Transcriptome and Interactome Predicts an ETP-ALL-Specific Transcriptional Footprint that Decodes its Developmental Propensity

Early T precursor acute lymphoblastic leukemia (ETP-ALL) exhibits poor clinical outcomes and high relapse rates following conventional chemotherapeutic protocols. Extensive developmental flexibility of the multipotent ETP-ALL blasts with considerable intra-population heterogeneity in terms of immunophenotype and prognostic parameters might be a target for novel therapeutic interventions. Using a public gene expression dataset (GSE28703) from NCBI GEO DataSets with 12 ETP-ALL and 40 non-ETP-ALL samples, such heterogeneity was found to be reflected in their transcriptome as well. Hub genes were identified from the STRING-derived functional interaction network of genes showing differential expression between ETP-ALL and non-ETP-ALL as well as variable expression across ETP-ALL. Nine genes (KIT, HGF, NT5E, PROM1, CD33, ANPEP, CDH2, IL1B, and CXCL2) among the hubs were further validated as possible diagnostic ETP-ALL markers using another gene expression dataset (GSE78132) with 17 ETP-ALL and 27 non-ETP-ALL samples. Linear dimensionality reduction analysis with the expression levels of the hub genes in ETP-ALL revealed their divergent inclinations towards different hematopoietic lineages, proposing them as novel indicators of lineage specification in the incompletely differentiated ETP-ALL blasts. This further led to the formulation of a personalized lineage score calculation algorithm, which uncovered a considerable B-lineage-bias in a substantial fraction of ETP-ALL subjects from the GSE28703 and GSE78132 cohorts. In addition, STRING-derived physical interactome of the potential biomarkers displayed complete segregation of the B-lineage-skewed markers from other lineage-associated factors, highlighting their distinct functionality and possible druggability in ETP-ALL. A panel of these biomarkers might be useful in pinpointing the dominant lineage specification programmes in the ETP-ALL blasts on a personalized level, urging the development of novel lineage-directed precision therapies as well as repurposing of existing therapies against leukemia of different hematopoietic lineages; which might overcome the drawbacks of conventional chemotherapy.

A Novel Case of Concurrent T-cell and Early T-cell Precursor Lymphoblastic Lymphoma in an Adolescent Female

In the context of an evolving understanding of early T-cell precursor (ETP) lymphoma and leukemia, we present a case of concurrent T-cell lymphoblastic lymphoma and ETP lymphoma in an adolescent female. To our knowledge, this represents the first reported case of both lymphoblastic lymphoma and ETP lymphoma as distinct and conjoined components of the same neoplasm. As an exception to current literature, our patient had a strictly lymphomatous ETP component with no leukemic manifestation. Her ETP component remained viable following induction, supporting ETP resistance to chemotherapy. The patient remains in remission 4 years postallogeneic matched sibling donor bone marrow transplant.

Venetoclax for Children and Adolescents with Acute Lymphoblastic Leukemia and Lymphoblastic Lymphoma

Simple Summary

Pediatric patients with relapsed or refractory acute lymphoblastic leukemia (ALL) or lymphoma (LBL) currently have unsatisfactory outcomes, and novel treatment options are needed. Venetoclax is approved for adult patients with several types of leukemia and is being investigated in the pediatric population. Here, we retrospectively reviewed the safety and efficacy of venetoclax for the treatment of ALL/LBL in the pediatric and young adult populations. The purpose of this study is to provide evidence that venetoclax is safe and effective to use in pediatric patients with ALL/LBL and should be considered in both the relapsed and upfront settings.

Abstract

Venetoclax is approved for adult patients with chronic lymphocytic leukemia and acute myeloid leukemia. Expanding its use to the pediatric population is currently under investigation, but more robust data are needed. We retrospectively analyzed the safety and efficacy of venetoclax in children/AYA with ALL/LBL. We identified 18 patients (T-cell ALL, n = 7; T-cell LBL, n = 6; B-cell ALL, n = 5) aged 6–22 years. No new venetoclax safety signals were identified; the most common toxicity was myelosuppression. No deaths occurred within 30 days from the start of the therapy. A mean of 2.6 (range 0–8) prior lines of therapy were given. The mean duration of venetoclax was 4.06 months (range 0.2–24.67 months). Complete remission was achieved in 11 (61%) patients. Of the eight patients who remain alive, four are continuing on venetoclax combination therapy, and four proceeded to hematopoietic stem cell transplantation. Three patients who initially achieved CR, later relapsed, and are deceased. Nine patients are deceased, and one patient was lost to follow-up. Overall survival is 9.14 months (range 1.1–33.1), and progression-free survival is 7.34 months (range 0.2–33.1). This is the largest cohort of pediatric/AYA patients who received venetoclax for ALL/LBL. Our data support the consideration of venetoclax-based regimens in pediatric patients with R/R ALL/LBL and its investigation as upfront therapy for T-cell ALL/LBL.

Inside the biology of early T-cell precursor acute lymphoblastic leukemia: the perfect trick

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is a rare, distinct subtype of T-ALL characterized by genomic instability, a dismal prognosis and refractoriness to standard chemotherapy. Since its first description in 2009, the expanding knowledge of its intricate biology has led to the definition of a stem cell leukemia with a combined lymphoid-myeloid potential: the perfect trick. Several studies in the last decade aimed to better characterize this new disease, but it was recognized as a distinct entity only in 2016. We review current insights into the biology of ETP-ALL and discuss the pathogenesis, genomic features and their impact on the clinical course in the precision medicine era today.

Long term outcome of a patient with relapsed refractory early thymic precursor acute lymphoblastic leukemia treated with daratumumab

The prognosis of patients with relapsed Early Thymic Precursor acute lymphoblastic leukemia (ETP-ALL) remains poor. Unlike B cell Precursor-ALL (BCP-ALL), there are no approved targeted therapies for ETP-ALL. Recent studies have identified a consistent expression of CD38 on the blasts of patients with T-ALL (both ETP-ALL and non ETP-ALL). Pre-clinical studies indicate that CD38 expression persists on the blasts of T-ALL even after receipt of conventional chemotherapy. These findings make CD38 an attractive targetable surface protein for patients with relapsed refractory T-ALL. We were the first to describe the clinical use of daratumumab in a patient of ETP-ALL, with relapsed disease post allogeneic transplant. We describe here the long term outcome of this patient more than 3 years after starting single agent daratumumab.

A Chinese Child Presented with Early T Cell Precursor Lymphoblastic Lymphoma

T cell lymphoblastic lymphoma (T-LBL) is regarded as the leukemic phase of T cell acute lymphoblastic leukemia (T-ALL). The early T cell precursors ALL/LBL (ETP-LBL/ALL) are derived from thymic cells at the ETP differentiation stage and recognized as a high-risk subgroup of T-ALL/LBL. Most of these cases presented with ALL at the disease onset, but the ETP-LBL phase is uncommon. Here, we report a patient who presented with ETP-LBL at the disease onset. In this case, ALL developed even despite receiving chemotherapy, but the patient achieved a complete remission with intensive chemotherapy.

A New Treatment Strategy for Early T-Cell Precursor Acute Lymphoblastic Leukemia: A Case Report and Literature Review

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is an aggressive and extremely fatal subtype of T-cell acute lymphoblastic leukemia (T-ALL), characterized by the similar transcriptional and immunophenotypic profiles to those of early T-cell precursors and positive expressions of myeloid antigens. Besides, the gene expression profile in ETP-ALL is similar to that in myeloid malignancies. The clinical characteristics, treatments and prognoses of ETP-ALL are significantly heterogeneous. In the present study, we reported a 43-year-old female patient who lacked terminal deoxynucleotidyl transferase (TDT) expression in immunophenotype and displayed mutations of fms-like tyrosine kinase-internal tandem duplication (FLT3-ITD), paired-box domain 5 (PAX5) and SH2B adaptor protein 3 (SH2B3) (PAX5 and SH2B3, the genes critical to B cell identity and function), which represent myeloid and precursor B-lineage associated gene mutations, respectively. It was a rare T-ALL or T-lineage case. Because of multiple poor prognostic factors in this case, conventional induction regimens, like hyper-CVAD (cyclophosphamide, vincristine, doxorubicin, dexamethasone), were invalid. The patient showed inadequate response, suggesting that this treatment was not employed on the basis of the immunophenotype. FLAG-IDA regimen (fludarabine, cytarabine [Ara-C], granulocyte-colony stimulating factor [G-CSF] and idarubicin), which is usually applied to eliminate leukemia cells, was administered combining with sorafenib as an effective induction chemotherapy. The case achieved long-term survival following the allogeneic hematopoietic stem cell transplantation (allo-HSCT). We recommend that adult ETP-ALL patients can be treated with a myeloid-oriented chemotherapy (as frontline induction treatment) along with gene-targeting inhibitors, followed by allo-HSCT.

Prognostic Value of the Immunological Subtypes of Adolescent and Adult T-Cell Lymphoblastic Lymphoma; an Ultra-High-Risk Pro-T/CD2(-) Subtype

(1) Background: T-cell lymphoblastic lymphoma (T-LBL) is extremely rare and highly aggressive, with no practical risk model defined yet. The prognostic value of T-LBL immunological subtypes is still a matter of controversy. (2) Methods: We re-evaluated 49 subsequent adult T-LBL patients treated according to the German Multicenter Study Group for Adult Acute Lymphoblastic Leukemia (GMALL) protocols, 05/93 (n = 20) and T-LBL 1/2004 (n = 29), 85.7% of which achieved complete remission (CR). (3) Results: The 5/10-year overall survival (OS) and event-free survival (EFS) were 62%/59% and 48%/43%, respectively. In 96% of patients, flow cytometry analyses defining the WHO 2008 immunophenotypes were available. Cortical, early/pro-T/CD2(-), early/pre-T/CD2(+), and mature subtypes were identified in 59.5%, 19%, 15%, and 6.5% of patients, respectively. Overall, 20% of patients had the early T-cell precursor (ETP)-LBL immunophenotype, as proposed by the WHO 2017 classification. For the early/pro-T/CD2(-) subtype, the five-year OS and EFS were 13% and 13%, while for all the other, non-pro-T subtypes, they were 69% and 67%. By multivariate analysis, only CD2(-) status and age > 35 years emerged as strong, independent factors influencing OS and EFS, while the risk of CR failure was influenced by age only (>35 years). (4) Conclusions: ETP was non-significant for OS, unless an ultra-high-risk pro-T/CD2(-) subtype was concerned.

Impact of disease status at allogeneic stem cell transplantation on adolescent and young adult patients with early T-cell precursor acute lymphoblastic leukemia

Early T-cell precursor (ETP) acute lymphoblastic leukemia (ALL) is an aggressive subset of T-cell ALL, and the role of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in adolescent and young adult (AYA) patients has not been sufficiently described. We retrospectively analysed the data of 30 AYA patients (19 in first complete remission [CR1], 3 in CR2, and 8 with active disease) with ETP-ALL who underwent myeloablative allogeneic hematopoietic stem cell transplantation (allo-HSCT) from HLA-matched related, n = 2, unrelated, n = 5, or HLA-haploidentical related, n = 23 donors with an emphasis on the impact of disease status on the outcomes of transplant. The stem cell source was unmanipulated G-CSF mobilized bone marrow or peripheral blood stem cells. All patients achieved neutrophil engraftment with full donor chimerism. The cumulative incidences of grade II to IV acute graft-versus-host disease (GVHD) and chronic GVHD at 2 years were 37% and 33%, respectively. Overall, 16 patients died. The causes of death were relapse (8 patients), infection (4 patients) and GVHD (4 patients). The estimated 2-year overall survival (OS) and leukemia-free survival (LFS) for the whole cohort were 47.8% and 46.2%, respectively. Patients transplanted in CR1/2 had significantly better 2-year OS and LFS than patients with active disease (61.7% vs. 12.5%, p = 0.02; and 58.3% vs. 12.5%, p = 0.04, respectively). There was a trend toward an inferior OS rate in those patients in CR1 with chemoresistance or in CR2 compared with patients in CR1 with chemosensitivity, although this did not reach statistical significance. Our data support allo-HSCT, especially from HLA-haploidentical donors as an effective therapeutic strategy in AYA patients with ETP-ALL and disease status was significantly associated with survival in these patients.

SET-NUP214 Fusion Gene Involved Early T-Cell Precursor Acute Lymphoblastic Leukemia in Adult with B Marker Expression

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is rare and associated with poor clinical outcome especially in adults. ETP tumor cells that express cross-lineage antigens or lack pan T markers usually pose big challenges to diagnosis, and their prognostic implications are therefore more uncertain. This study reports the unique case of a 44-year-old woman with breast mass as the initial presentation of acute leukemia possessing both T- and B-cell features (cytoplasmic CD3⁺CD7⁺CD19⁺CD79a⁺). Despite the presence of gene rearrangements of IGH and IGK probably in a small amount of B cells, the patient was diagnosed with T-ALL mainly according to WHO criteria, and further ETP-ALL rather than mixed phenotype ALL based on additional positive expression of stem/myeloid lineage antigens (CD34⁺CD13⁺CD33⁺HLA-DR⁺). Moreover, in spite of normal karyotype, SET-NUP214 gene fusion is identified, which has not been described in ETP-ALL with bi-phenotype. After intensive chemotherapy, the patient achieved short-term morphologic complete remission but relapsed within one month. This report may expand immunophenotype and clinical behavior of ETP-ALL in adults. Comprehensive evaluations are emphasized in making a differential diagnosis and distinguishing subtypes of acute leukemia.