An effective modestly intensive re-induction regimen with bortezomib in relapsed or refractory paediatric acute lymphoblastic leukaemia

Relapsed/Refractory T- Acute Lymphoblastic Leukemia - Current Options and Future Directions

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children. The T-cell subtype (T-ALL) accounts for 10-15% of pediatric ALL cases and has been historically associated with outcomes inferior to those of B-cell ALL (B-ALL). The prognosis of T-ALL has significantly improved with contemporary intensive pediatric regimens. However, most children with relapsed T-ALL have dismal outcomes and fewer therapeutic salvage options than those available for B-ALL. After demonstrating efficacy in relapsed T-ALL, nelarabine is being increasingly incorporated into frontline T-ALL regimens. The development of genomic sequencing has led to the identification of new T-ALL subgroups and potential targeted therapeutic approaches which could improve patients' outcomes and reduce the toxicity associated with current therapy. Immunotherapy and cellular therapy regimens are also under early investigation in T-cell malignancies. This review outlines the clinical and biological characteristics of T-ALL and provides an overview of novel treatment options for refractory and relapsed T-ALL.

Infectious Complications of Targeted Therapies in Children with Leukemias and Lymphomas

Simple Summary

Targeted therapies in children with hematological malignancies moderate the effects of cytotoxic therapy, thus improving survival rates. They have emerged over the last decade and are used in combination with or after the failure of conventional chemotherapy and as bridging therapy prior to hematopoietic stem cell transplantation (HSCT). Nowadays, there is a growing interest in their efficacy and safety in pediatric patients with refractory or relapsed disease. The compromised immune system, even prior to therapy, requires prompt monitoring and treatment. In children with hematological malignancies, targeted therapies are associated with a comparable incidence of infectious complications to adults. The exact impact of these agents that have different mechanisms of action and are used after conventional chemotherapy or HSCT is difficult to ascertain. Clinicians should be cautious of severe infections after the use of targeted therapies, especially when used in combination with chemotherapy.

Abstract

The aim of this review is to highlight mechanisms of immunosuppression for each agent, along with pooled analyses of infectious complications from the available medical literature. Rituximab confers no increase in grade ≥3 infectious risks, except in the case of patients with advanced-stage non-Hodgkin lymphoma. Gemtuzumab ozogamicin links with high rates of grade ≥3 infections which, however, are comparable with historical cohorts. Pembrolizumab exhibits a favorable safety profile in terms of severe infections. Despite high rates of hypogammaglobulinemia (HGG) with blinatumomab, low-grade ≥3 infection rates were observed, especially in the post-reinduction therapy of relapsed B-acute lymphoblastic leukemia. Imatinib and nilotinib are generally devoid of severe infectious complications, but dasatinib may slightly increase the risk of opportunistic infections. Data on crizotinib and pan-Trk inhibitors entrectinib and larotrectinib are limited. CAR T-cell therapy with tisagenlecleucel is associated with grade ≥3 infections in children and is linked with HGG and the emergence of immune-related adverse events. Off-label therapies inotuzumab ozogamicin, brentuximab vedotin, and venetoclax demonstrate low rates of treatment-related grade ≥3 infections, while the addition of bortezomib to standard chemotherapy in T-cell malignancies seems to decrease the infection risk during induction. Prophylaxis, immune reconstitution, and vaccinations for each targeted agent are discussed, along with comparisons to adult studies.

The Role of Proteasome Inhibitors in Treating Acute Lymphoblastic Leukaemia

Acute lymphoblastic leukaemia (ALL) is an aggressive haematolymphoid malignancy. The prognosis of ALL is excellent in paediatric population, however the outcome of relapse/refractory disease is dismal. Adult ALL has less favourable prognosis and relapse/refractory disease is not uncommonly encountered. Bortezomib is the first generation proteasome inhibitor licensed to treat plasma cell myeloma and mantle cell lymphoma with favourable side effect profile. Efficacy of bortezomib had been proven in other solid tumors. Clinical studies showed promising response for proteasome inhibitors in treating relapse/refractory ALL. Thus, proteasome inhibitors are attractive alternative agents for research in treating ALL. In the review article, we will introduce different proteasome inhibitors and their difference in pharmacological properties. Moreover, the mechanism of action of proteasome inhibitors on ALL will be highlighted. Finally, results of various clinical studies on proteasome inhibitors in both paediatric and adult ALL will be discussed. This review article provides the insights on the use of proteasome inhibitors in treating ALL with a summary of mechanism of action in ALL which facilitates future research on its use to improve the outcome of ALL.

A Semi-Mechanistic Population Pharmacokinetic/Pharmacodynamic Model of Bortezomib in Pediatric Patients with Relapsed/Refractory Acute Lymphoblastic Leukemia

INTRODUCTION

The pharmacokinetics (PK) of the 20S proteasome inhibitor bortezomib are characterized by a large volume of distribution and a rapid decline in plasma concentrations within the first hour after administration. An increase in exposure was observed in the second week of treatment, which has previously been explained by extensive binding of bortezomib to proteasome in erythrocytes and peripheral tissues. We characterized the nonlinear population PK and pharmacodynamics (PD) of bortezomib in children with acute lymphoblastic leukemia.

METHODS

Overall, 323 samples from 28 patients were available from a pediatric clinical study investigating bortezomib at an intravenous dose of 1.3 mg/m² twice weekly (Dutch Trial Registry number 1881/ITCC021). A semi-physiological PK model for bortezomib was first developed; the PK were linked to the decrease in 20S proteasome activity in the final PK/PD model.

RESULTS

The plasma PK data were adequately described using a two-compartment model with linear elimination. Increased concentrations were observed in week 2 compared with week 1, which was described using a Langmuir binding model. The decrease in 20S proteasome activity was best described by a direct effect model with a sigmoidal maximal inhibitory effect, representing the relationship between plasma concentrations and effect. The maximal inhibitory effect was 0.696 pmol AMC/s/mg protein (95% confidence interval 0.664-0.728) after administration.

CONCLUSION

The semi-physiological model adequately described the nonlinear PK and PD of bortezomib in plasma. This model can be used to further optimize dosing of bortezomib.

Treatment of children with relapsed and refractory acute lymphoblastic leukemia with mitoxantrone, vincristine, pegaspargase, dexamethasone, and bortezomib

BACKGROUND

The treatment of relapsed or refractory acute lymphoblastic leukemia (ALL) in children is challenging and new treatment options are needed. Bortezomib is a proteasome inhibitor with activity in pediatric acute lymphoblastic leukemia. Adding bortezomib to standard reinduction chemotherapy in relapsed and refractory pediatric ALL has produced very good response rates in prior studies.

METHODS

We evaluated bortezomib in combination with reinduction therapy (ALL R3) in 10 children with relapsed or refractory ALL. Bortezomib (1.3 mg/m² /dose) was administered to patients on days 1, 4, 8, and 11. In addition, patients received mitoxantrone, dexamethasone, pegaspargase, vincristine, and intrathecal methotrexate over 4 weeks.

RESULTS

Of the 10 patients, eight (80%) achieved a complete remission (CR) or complete remission with incomplete recovery (CRi). Of the patients in CR, two had undetectable minimal residual disease by flow cytometry (<0.01%). Five patients were subsequently treated with a stem cell transplant. All eight patients that achieved CR or CRi eventually relapsed. One patient remains alive following treatment with tisagenlecleucel after relapse. Grade 3 or higher infections occurred in four out of 10 patients, and other toxicities commonly associated with bortezomib were not seen.

CONCLUSIONS

In children with relapsed or refractory ALL, the addition of bortezomib to reinduction chemotherapy that includes mitoxantrone produces a complete response in the majority of cases and does not lead to excessive toxicity.

Pharmacotherapy in Children and Adolescents: Oncology

Pharmacotherapy in paediatric oncology is a difficult task. It is challenging to determine the optimal dose in children of different age groups. In addition, anticancer drugs display severe side effects reducing the quality of life. Late effects like secondary tumours and cardiotoxicity can be apparent years after treatment and must be taken into account when planning treatment schedules. Classical cytoreducing agents are still of great importance in treating children with leukaemia and solid tumours. In addition, drugs developed by rational drug design (targeted drugs) are a very important part of many treatment protocols, and newer drugs are emerging in several types of cancer. Unfortunately, there is only limited experience with newer drugs in children, because new drugs are mostly developed for adults. Complicated therapy regimens require a solid knowledge of the pharmacology of the drugs applied. This chapter attempts to introduce some pharmacological knowledge for the most important anticancer drugs in children with a focus on side effects and age-specific considerations.

Bortezomib for the Treatment of Hematologic Malignancies: 15 Years Later

Bortezomib is a dipeptidyl boronic acid that selectively inhibits the ubiquitin proteasome pathway, which plays a role in the degradation of many intracellular proteins. It is the first-in-class selective and reversible inhibitor of the 26S proteasome, with antiproliferative and antitumor activity. It exerts its anti-neoplastic action mainly via the inhibition of the nuclear factor-κB pathway components associated with cell proliferation, apoptosis, and angiogenesis. The drug has revolutionized the treatment of multiple myeloma and, more recently, mantle cell lymphoma. In 2003, bortezomib received accelerated approval from the US Food and Drug Administration for the treatment of relapsed/refractory multiple myeloma and in 2008 for patients with previously untreated multiple myeloma. In 2006, bortezomib was approved for the treatment of refractory/relapsed mantle cell lymphoma and, in 2014, for previously untreated mantle cell lymphoma. Bortezomib has also demonstrated clinical efficacy both as a single drug and in combination with other agents in light chain amyloidosis, lymphoplasmacytic lymphoma/Waldenstrom macroglobulinemia, and peripheral T-cell lymphomas. Furthermore, continued clinical studies are required to confirm its value for patients with indolent and aggressive B-cell non-Hodgkin lymphomas and acute leukemias.

"Feasible and effective administration of Bortezomib with Rituximab in children with relapsed/resistant B-cell precursor acute lymphoblastic leukemia (BCP-ALL): A step toward the first line"

Despite a high cure rate in childhood BCP-ALL, 20% of children still presents with relapse, mostly due to a persistent leukemic clone during the first-line treatment. In this context, obtaining a molecular remission is crucial for reaching a successful allogeneic hematopoietic stem cell transplantation. Bortezomib was effectively administered to children with resistant/relapsed (r/r) BCP-ALL. Moreover, high risk ALL is characterized by the increasing expression of CD20. For the first time we reported two children with r/r BCP-ALL who received a treatment schema including Bortezomib and Rituximab, achieving morphological and molecular remission. Children with high risk features, such as persistent minimal residual disease during induction, will benefit from this combination. Is it time to move toward the first line?

Efficacy and safety of a bortezomib and reduced-intensity cytarabine-based protocol, TMC ALLR1, for relapsed childhood ALL in India

The feasibility of bortezomib (BZB) in induction and reduced cytarabine doses in intensification was evaluated in children with relapsed acute lymphoblastic leukaemia (rALL) at a single centre in India. Of 55 children with rALL, 23 received supportive care and 7 refused treatment, with a median survival of 2 (interquartile range 1-6) months. Twenty-two (88%) of 25 children who were treated achieved second remission and 9 (69%) of 13 had end-of-induction minimal residual disease of <10-4 . The lower cytarabine dose was associated with decreased hospitalisation. One-year event-free and overall survival for the treated group was 74·7% (95% confidence interval 52-88) and 79·6% (58-91) respectively.

Cell-type-specific sensitivity of bortezomib in the methotrexate-resistant primary central nervous system lymphoma cells

BACKGROUND

Methotrexate (MTX) is used in first-line treatment of primary central nervous system lymphoma (PCNSL), but most cases result in relapse-acquired resistance to MTX. However, only few studies have reported on internal changes and chemotherapies in PCNSL.

METHODS

In this study, we generated two MTX-resistant PCNSL cell lines, designated MTX-HKBML and MTX-TK, in addition to a MTX-resistant Burkitt lymphoma cell line, designated MTX-RAJI. We examined gene expression changes and drug sensitivity to a proteasome inhibitor, bortezomib, in these cells.

RESULTS

Cytotoxic tests revealed that the 50% inhibitory concentration for MTX in MTX-HKBML is markedly higher than that in the other two cell lines. Expression of the genes in MTX and folate metabolisms, including gamma-glutamyl hydrolase and dihydrofolate reductase, are upregulated in both MTX-HKBML and MTX-TK, whereas the gene expression of folylpolyglutamate synthetase, thymidylate synthase, and methylenetetrahydrofolate dehydrogenase 1 were upregulated and downregulated in MTX-HKBML and MTX-TK, respectively, on the other hand, bortezomib sensitivity was observed in MTX-TK, as compared with control TK, but not in MTX-HKBML.

CONCLUSION

These results indicate the cell-type-specific changes downstream of metabolic pathways for MTX and folate, bortezomib sensitivity, and purine and pyrimidine syntheses, in each PCNSL cell line. The MTX-resistant lymphoma cell lines established may be useful for in vitro relapse models for MTX and development of salvage chemotherapy and drug discovery.