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In the development of novel immunotherapeutic approaches, the step of target identification is a challenging process, because it aims at identifying robust tumor‐associated antigens (TAAs) specific for the pathological population and causing no off‐target effects. Here we propose CD72 as a novel and robust TAA for pediatric acute leukemias. We provided an outline of CD72 expression assessed by flow cytometry on a variety of cancer cell lines and primary samples, including normal bone marrow (BM) samples and hematopoietic stem and progenitor cells. We analyzed CD 72 expression on a cohort of 495 pathological pediatric BM aspirates, including: 215 B‐cell precursor acute lymphoblastic leukemias (BCP‐ALL), 156 acute myeloid leukemias (AMLs), 88 T‐lineage ALLs or lymphoblastic lymphomas with BM infiltration, 13 B‐lineage lymphoblastic lymphomas with BM infiltration, 9 myelodysplastic syndromes with increased blasts (5%–9% blasts on BM: MDS‐IB1) and 14 non‐hematopoietic solid tumors infiltrating BM. Results showed that CD72 is highly expressed in almost all BCP‐ALL and the majority of AML at diagnosis, including BCP‐ALL cases characterized by CD19 loss. These findings support a potential role for advanced diagnostics and novel immunotherapy approaches, providing a pan‐ALL and AML target. [ABSTRACT FROM AUTHOR]

Asparaginase is widely used in chemotherapeutic regimens for the treatment of acute lymphoblastic leukemia (ALL) and has led to a substantial improvement in cure rates, especially in children. Optimal therapeutic effects depend on a complete and sustained depletion of serum asparagine. However, pronounced interpatient variability, differences in pharmacokinetic properties between asparaginases and the formation of asparaginase antibodies make it difficult to predict the degree of asparagine depletion that will result from a given dose of asparaginase. The pharmacological principles underlying asparaginase therapy in the treatment of ALL are summarized in this article. A better understanding of the many factors that influence asparaginase activity and subsequent asparagine depletion may allow physicians to tailor treatment to the individual, maximizing therapeutic effect and minimizing treatment-related toxicity. Therapeutic drug monitoring provides a means of assessing a patient's current depletion status and can be used to better evaluate the potential benefit of treatment adjustments. [ABSTRACT FROM PUBLISHER]

In the last two decades great improvements have been made in the treatment of childhood acute lymphoblastic leukemia, with 5-year overall survival rates currently approaching almost 90%. In comparison, results reported in adolescents and young adults (AYAs) are relatively poor. In adults, results have improved, but are still lagging behind those obtained in children. Possible reasons for this different pattern of results include an increased incidence of unfavorable and a decreased incidence of favorable cytogenetic abnormalities in AYAs compared with children. Furthermore, in AYAs less intensive treatments (especially lower cumulative doses of drugs such as asparaginase, corticosteroids and methotrexate) and longer gaps between courses of chemotherapy are planned compared to those in children. However, although favorable results obtained in AYAs receiving pediatric protocols have been consistently reported in several international collaborative trials, physicians must also be aware of the specific toxicity pattern associated with increased success in AYAs, since an excess of toxicity may compromise overall treatment schedule intensity. Cooperative efforts between pediatric and adult hematologists in designing specific protocols for AYAs are warranted. [ABSTRACT FROM AUTHOR]

Asparaginases are a cornerstone of treatment protocols for acute lymphoblastic leukemia (ALL) and are used for remission induction and intensification treatment in all pediatric regimens and in the majority of adult treatment protocols. Extensive clinical data have shown that intensive asparaginase treatment improves clinical outcomes in childhood ALL. Three asparaginase preparations are available: the native asparaginase derived from Escherichia coli (E. coli asparaginase), a pegylated form of this enzyme (PEG-asparaginase), and a product isolated from Erwinia chrysanthemi, ie, Erwinia asparaginase. Clinical hypersensitivity reactions and silent inactivation due to antibodies against E. coli asparaginase, lead to inactivation of E coli asparaginase in up to 60% of cases. Current treatment protocols include E. coli asparaginase or PEG-asparaginase for first-line treatment of ALL. Typically, patients exhibiting sensitivity to one formulation of asparaginase are switched to another to ensure they receive the most efficacious treatment regimen possible. Erwinia asparaginase is used as a second- or third-line treatment in European and US protocols. Despite the universal inclusion of asparaginase in such treatment protocols, debate on the optimal formulation and dosage of these agents continues. This article provides an overview of available evidence for optimal use of Erwinia asparaginase in the treatment of ALL. [ABSTRACT FROM AUTHOR]

Simple Summary: Blinatumomab, a bispecific T-cell engager, binding T-cell CD3 and B-cell CD19 antigens, has remarkably enlarged the treatment options for patients with relapsed/refractory B-cell precursor acute lymphoblastic leukemia (r/r BCP-ALL). The aim of our study was to retrospectively assess the safety and efficacy profile of blinatumomab in 39 r/r ALL children treated in seven AIEOP centers in a compassionate or off-label program. This report is among the largest multicentric real-life retrospective analyses on blinatumomab in pediatric r/r BCP ALL. Blinatumomab showed a tolerable safety profile (34.8% of adverse events ≥grade 3, no cytokine release syndrome and no associated toxic deaths) and proved to be very effective (complete remission rate 46% in the 13 patients with ≥5% blasts and 81% PCR/FC MRD negativity in the 26 patients with <5% blasts) in this group of patients affected by r/r BCP-ALL already treated in the frame of very intensive front-line and relapsed protocols. Five-year event-free survival in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL) currently exceeds 80–85%. However, 15–20% of patients still experience a relapsed/refractory disease. From 1 January 2015 to 31 December 2020, thirty-nine patients, 0–21 years old with r/r BCP-ALL were treated with blinatumomab with the aim of inducing remission (n = 13) or reducing MRD levels (n = 26) in the frame of different multiagent chemotherapy schedules, in seven AIEOP centers. Patients were treated in compassionate and/or off-label settings and were not enrolled in any controlled clinical trials. Treatment was well tolerated; 22 (56.4%) patients reported adverse events (AE) on a total of 46 events registered, of which 27 (58.7%) were ≤2 grade according to CTCAE. Neurological AEs were 18 (39.1%); only two patients required transient blinatumomab discontinuation. Complete remission (CR) rate was 46% for the 13 patients treated with ≥5% blasts and 81% PCR/FC MRD negativity in the 26 patients with blasts < 5%. Median relapse-free survival was 33.4 months (95% CI; 7.5–59.3); median overall survival was not reached over a mean follow-up of 16 months. In our study, as in other real-life experiences, blinatumomab proved to be effective and well-tolerated, able to induce a high rate of CR and MRD negativity. [ABSTRACT FROM AUTHOR]