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Blinatumomab is the first in its class bispecific T-cell engager monoclonal antibody, which binds to CD19 expressed on B-cells and CD3 expressed on T-cells, resulting in lysis of CD19-positive cells common in B-cell malignancies. Blinatumomab is Food and Drug Administration (FDA) approved for the treatment of adults and children with relapsed/refractory or minimal residual disease (MRD) positive precursor B-cell ALL (B-ALL). Despite impressive efficacy for the approved indications and favorable toxicity profile compared to standard-of-care chemotherapy, blinatumomab presents unique health-system challenges related to preparation, administration, toxicity monitoring and medication error prevention. Blinatumomab delivery also offers plethora of opportunities for interdisciplinary planning and collaboration. The purpose of this paper is to discuss practical considerations for safe blinatumomab delivery from the pharmacy and nursing perspectives. [ABSTRACT FROM AUTHOR]

The MTXPK.org webtool was launched in December 2019 and was developed to facilitate model‐informed supportive care and optimal use of glucarpidase following the administration of high‐dose methotrexate (HDMTX). One limitation identified during the original development of the MTXPK.org tool was the perceived generalizability because the modeled population comprised solely of Nordic pediatric patients receiving 24‐h infusions for the treatment of acute lymphoblastic leukemia. The goal of our study is to describe the pharmacokinetics of HDMTX from a diverse patient population (e.g., races, ethnicity, indications for methotrexate, and variable infusion durations) and identify meaningful factors that account for methotrexate variability and improve the model's performance. To do this, retrospectively analyzed pharmacokinetic and toxicity data from pediatric and adolescent young adult patients who were receiving HDMTX (>0.5 g/m2) for the treatment of a cancer diagnosis from three pediatric medical centers. We performed population pharmacokinetic modeling referencing the original MTXPK.org NONMEM model (includes body surface area and serum creatinine as covariates) on 1668 patients, 7506 administrations of HDMTX, and 30,250 concentrations. Our results support the parameterizations of short infusion duration (<8 h) and the presence of Down syndrome on methotrexate clearance, the parameterization of severe hypoalbuminemia (<2.5 g/dL) on the intercompartmental clearance (Q2 and Q3), and the parameterization of pleural effusion on the volume of distribution (V1 and V2). These novel parameterizations will increase the generalizability of the MTXPK.org model once they are added to the webtool. [ABSTRACT FROM AUTHOR]

Simple Summary: Novel well-tolerated agents are urgently needed to improve outcomes for children with acute myeloid leukemia. Atovaquone is an anti-infective agent which can be used to prevent and treat a type of pneumonia that all children with acute myeloid leukemia require prophylaxis against. In addition, atovaquone has been shown to have anti-leukemic effects. In the clinical trial described here, atovaquone is tolerated well during intensive chemotherapy with no attributable adverse events. However, perhaps due to side effects from intensive chemotherapy, plasma concentrations of atovaquone were lower than expected. Thus, for patients getting intensive leukemia-directed therapy, atovaquone plasma concentrations should be followed. Additionally, embedded correlative biology studies demonstrated that atovaquone produced anti-leukemia effects in patient samples in vitro and in patient-derived xenograft models. Our results support further study of atovaquone and other agents that target the dysregulated metabolism of acute myeloid leukemia cells. Survival of pediatric AML remains poor despite maximized myelosuppressive therapy. The pneumocystis jiroveci pneumonia (PJP)-treating medication atovaquone (AQ) suppresses oxidative phosphorylation (OXPHOS) and reduces AML burden in patient-derived xenograft (PDX) mouse models, making it an ideal concomitant AML therapy. Poor palatability and limited product formulations have historically limited routine use of AQ in pediatric AML patients. Patients with de novo AML were enrolled at two hospitals. Daily AQ at established PJP dosing was combined with standard AML therapy, based on the Medical Research Council backbone. AQ compliance, adverse events (AEs), ease of administration score (scale: 1 (very difficult)-5 (very easy)) and blood/marrow pharmacokinetics (PK) were collected during Induction 1. Correlative studies assessed AQ-induced apoptosis and effects on OXPHOS. PDX models were treated with AQ. A total of 26 patients enrolled (ages 7.2 months–19.7 years, median 12 years); 24 were evaluable. A total of 14 (58%) and 19 (79%) evaluable patients achieved plasma concentrations above the known anti-leukemia concentration (>10 µM) by day 11 and at the end of Induction, respectively. Seven (29%) patients achieved adequate concentrations for PJP prophylaxis (>40 µM). Mean ease of administration score was 3.8. Correlative studies with AQ in patient samples demonstrated robust apoptosis, OXPHOS suppression, and prolonged survival in PDX models. Combining AQ with chemotherapy for AML appears feasible and safe in pediatric patients during Induction 1 and shows single-agent anti-leukemic effects in PDX models. AQ appears to be an ideal concomitant AML therapeutic but may require intra-patient dose adjustment to achieve concentrations sufficient for PJP prophylaxis. [ABSTRACT FROM AUTHOR]

Importance: Standard chemotherapy for first relapse of B-cell acute lymphoblastic leukemia (B-ALL) in children, adolescents, and young adults is associated with high rates of severe toxicities, subsequent relapse, and death, especially for patients with early relapse (high risk) or late relapse with residual disease after reinduction chemotherapy (intermediate risk). Blinatumomab, a bispecific CD3 to CD19 T cell-engaging antibody construct, is efficacious in relapsed/refractory B-ALL and has a favorable toxicity profile.Objective: To determine whether substituting blinatumomab for intensive chemotherapy in consolidation therapy would improve survival in children, adolescents, and young adults with high- and intermediate-risk first relapse of B-ALL.Design, Setting, and Participants: This trial was a randomized phase 3 clinical trial conducted by the Children's Oncology Group at 155 hospitals in the US, Canada, Australia, and New Zealand with enrollment from December 2014 to September 2019 and follow-up until September 30, 2020. Eligible patients included those aged 1 to 30 years with B-ALL first relapse, excluding those with Down syndrome, Philadelphia chromosome-positive ALL, prior hematopoietic stem cell transplant, or prior blinatumomab treatment (n = 669).Interventions: All patients received a 4-week reinduction chemotherapy course, followed by randomized assignment to receive 2 cycles of blinatumomab (n = 105) or 2 cycles of multiagent chemotherapy (n = 103), each followed by transplant.Main Outcome and Measures: The primary end point was disease-free survival and the secondary end point was overall survival, both from the time of randomization. The threshold for statistical significance was set at a 1-sided P <.025.Results: Among 208 randomized patients (median age, 9 years; 97 [47%] females), 118 (57%) completed the randomized therapy. Randomization was terminated at the recommendation of the data and safety monitoring committee without meeting stopping rules for efficacy or futility; at that point, 80 of 131 planned events occurred. With 2.9 years of median follow-up, 2-year disease-free survival was 54.4% for the blinatumomab group vs 39.0% for the chemotherapy group (hazard ratio for disease progression or mortality, 0.70 [95% CI, 0.47-1.03]); 1-sided P = .03). Two-year overall survival was 71.3% for the blinatumomab group vs 58.4% for the chemotherapy group (hazard ratio for mortality, 0.62 [95% CI, 0.39-0.98]; 1-sided P = .02). Rates of notable serious adverse events included infection (15%), febrile neutropenia (5%), sepsis (2%), and mucositis (1%) for the blinatumomab group and infection (65%), febrile neutropenia (58%), sepsis (27%), and mucositis (28%) for the chemotherapy group.Conclusions and Relevance: Among children, adolescents, and young adults with high- and intermediate-risk first relapse of B-ALL, postreinduction treatment with blinatumomab compared with chemotherapy, followed by transplant, did not result in a statistically significant difference in disease-free survival. However, study interpretation is limited by early termination with possible underpowering for the primary end point.Trial Registration: ClinicalTrials.gov Identifier: NCT02101853. [ABSTRACT FROM AUTHOR]