Inotuzumab ozogamicin in adults with relapsed or refractory CD22-positive acute lymphoblastic leukemia: a phase 1/2 study

Inotuzumab ozogamicin in adult acute lymphoblastic leukemia: Development, current status, and future directions

Inotuzumab ozogamicin (InO) is an antibody-drug conjugate approved for the treatment of relapsed/refractory B-cell acute lymphoblastic leukemia (ALL). Several clinical trials are investigating InO in combination with low-intensity chemotherapy or other anti-ALL-targeted therapies in the salvage and frontline settings, notably in older adults who often cannot tolerate intensive chemotherapy and tend to have higher-risk disease. InO is also increasingly used to bridge patients to hematopoietic stem cell transplantation (HSCT), in sequence with chimeric antigen receptor T-cell therapy, to eliminate measurable residual disease and to prevent post-HSCT relapse. Veno-occlusive disease/sinusoidal obstruction syndrome is a potential complication of InO treatment, particularly when followed by HSCT. Herein, the authors review the historical development and current status of InO, strategies for mitigating the risk of InO-related veno-occlusive disease/sinusoidal obstruction syndrome, and future directions for InO research and clinical use.

Association of leukemic molecular profile with efficacy of inotuzumab ozogamicin in adults with relapsed/refractory ALL

ABSTRACT

The phase 3 INO-VATE trial demonstrated higher rates of remission, measurable residual disease negativity, and improved overall survival for patients with relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL) who received inotuzumab ozogamicin (InO) vs standard-of-care chemotherapy (SC). Here, we examined associations between genomic alterations and the efficacy of InO. Of 326 randomized patients, 91 (InO, n = 43; SC, n = 48) had samples evaluable for genomic analysis. The spectrum of gene fusions and other genomic alterations observed was comparable with prior studies of adult ALL. Responses to InO were observed in all leukemic subtypes, genomic alterations, and risk groups. Significantly higher rates of complete remission (CR)/CR with incomplete count recovery were observed with InO vs SC in patients with BCR::ABL1-like ALL (85.7% [6/7] vs 0% [0/5]; P = .0076), with TP53 alterations (100% [5/5] vs 12.5% [1/8]; P = .0047), and in the high-risk BCR::ABL1- (BCR::ABL1-like, low-hypodiploid, KMT2A-rearranged) group (83.3% [10/12] vs 10.5% [2/19]; P < .0001). This retrospective, exploratory analysis of the INO-VATE trial demonstrated potential for benefit with InO for patients with R/R ALL across leukemic subtypes, including BCR::ABL1-like ALL, and for those bearing diverse genomic alterations. Further confirmation of the efficacy of InO in patients with R/R ALL exhibiting the BCR::ABL1-like subtype or harboring TP53 alterations is warranted. This trial was registered at www.ClinicalTrials.gov as #NCT01564784.

MRD in Philadelphia Chromosome-Positive ALL: Methodologies and Clinical Implications

PURPOSE OF REVIEW

Measurable residual disease (MRD) is integral in the management of Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). This review discusses the current methods used to evaluate MRD as well as the interpretation, significance, and incorporation of MRD in current practice.

RECENT FINDINGS

New molecular technologies have allowed the detection of MRD to levels as low as 10- 6. The most used techniques to evaluate MRD are multiparametric flow cytometry (MFC), quantitative reverse transcription polymerase chain reaction (RT-qPCR), and high-throughput next-generation sequencing (NGS). Each method varies in terms of advantages, disadvantages, and MRD sensitivity. MRD negativity after induction treatment and after allogeneic hematopoietic cell transplantation (HCT) is an important prognostic marker that has consistently been shown to be associated with improved outcomes. Blinatumomab, a new targeted therapy for Ph + ALL, demonstrates high efficacy in eradicating MRD and improving patient outcomes. In the relapsed/refractory setting, the use of inotuzumab ozogamicin and tisagenlecleucel has shown promise in eradicating MRD. The presence of MRD has become an important predictive measure in Ph + ALL. Current studies evaluate the use of MRD in treatment decisions, especially in expanding therapeutic options for Ph + ALL, including tyrosine kinase inhibitors, targeted antibody therapies, chimeric antigen receptor cell therapy, and HCT.

Inotuzumab ozogamicin for the treatment of adult acute lymphoblastic leukemia: past progress, current research and future directions

Inotuzumab ozogamicin (INO) is an anti-CD22 antibody-drug conjugate that was first evaluated in B-cell lymphomas but was subsequently shown to be highly effective in acute lymphoblastic leukemia (ALL). INO improved response rates and survival in a randomized study in adults with relapsed/refractory B-cell ALL, leading to its regulatory approval in the United States in 2017. While the formal approval for INO is as monotherapy in relapsed/refractory ALL, subsequent studies with INO administered in combination with chemotherapy and/or blinatumomab both in the frontline and salvage settings have yielded promising results. In this review, we discuss the clinical development of INO in ALL, highlighting lessons learned from the initial clinical trials of INO, as well as the many ongoing studies that are seeking to expand the role of INO in ALL.

Immune therapies of B-cell acute lymphoblastic leukaemia in children and adults

B-cell acute lymphoblastic leukaemia (B-cell ALL) is a common haematologic cancer in children and adults. About 10 percent of children and 50 percent of adults fail to achieve a histological complete remission or subsequently relapse despite current anti-leukaemia drug therapies and/or haematopoietic cell transplants. Several new immune therapies including monoclonal antibodies and chimeric antigen receptor (CAR)-T-cells are proved safe and effective in this setting. We review data on US Food and Drug Administration (FDA)-approved immune therapies for B-cell ALL in children and adults including blinatumomab, inotuzumab ozogamicin, tisagenlecleucel, and brexucabtagene autoleucel. We also summarize pharmaco-dynamics, pharmaco-kinetics, and pharmaco-economics of these interventions.

A review of the clinical efficacy of FDA-approved antibody‒drug conjugates in human cancers

While strategies such as chemotherapy and immunotherapy have become the first-line standard therapies for patients with advanced or metastatic cancer, acquired resistance is still inevitable in most cases. The introduction of antibody‒drug conjugates (ADCs) provides a novel alternative. ADCs are a new class of anticancer drugs comprising the coupling of antitumor mAbs with cytotoxic drugs. Compared with chemotherapeutic drugs, ADCs have the advantages of good tolerance, accurate target recognition, and small effects on noncancerous cells. ADCs occupy an increasingly important position in the therapeutic field. Currently, there are 13 Food and Drug Administration (FDA)‒approved ADCs and more than 100 ADC drugs at different stages of clinical trials. This review briefly describes the efficacy and safety of FDA-approved ADCs, and discusses the related problems and challenges to provide a reference for clinical work.

Targeting CD22 for B-cell hematologic malignancies

CD19-targeted chimeric receptor antigen (CAR)-T cell therapy has shown remarkable clinical efficacy in the treatment of relapsed or refractory (R/R) B-cell malignancies. However, 30%-60% of patients eventually relapsed, with the CD19-negative relapse being an important hurdle to sustained remission. CD22 expression is independent of CD19 expression in malignant B cells. Consequently, CD22 is a potential alternative target for CD19 CAR-T cell-resistant patients. CD22-targeted therapies, mainly including the antibody-drug conjugates (ADCs) and CAR-T cells, have come into wide clinical use with acceptable toxicities and promising efficacy. In this review, we explore the molecular and physiological characteristics of CD22, development of CD22 ADCs and CAR-T cells, and the available clinical data on CD22 ADCs and CAR-T cell therapies. Furthermore, we propose some perspectives for overcoming tumor escape and enhancing the efficacy of CD22-targeted therapies.

Inotuzumab ozogamicin in B-cell precursor acute lymphoblastic leukemia: efficacy, toxicity, and practical considerations

Inotuzumab ozogamicin (InO) is an antibody drug conjugate composed of a humanized monoclonal antibody targeting the cell surface receptor CD22 coupled to a cytotoxic calicheamicin payload via an acid labile linker. InO has shown significant activity in relapsed and refractory B-cell precursor acute lymphoblastic leukemia (BCP-ALL) in both single agent and combination chemotherapy regimens in adult and pediatric trials. Its use in newly diagnosed elderly patients has also been established while clinical trials investigating its use in newly diagnosed pediatric patients and fit adults are ongoing. Notable toxicities include sinusoidal obstruction syndrome (SOS), particularly in patients who undergo hematopoietic stem cell transplantation (HSCT) after InO as well as myelosuppression and B-cell aplasia which confer increased infection risk, particularly in combination with cytotoxic chemotherapy. In the relapsed/refractory (R/R) setting, the planned subsequent curative therapy modality must be considered when using InO to mitigate SOS risk if proceeding to HSCT and account for potential B-cell aplasia if proceeding to chimeric antigen receptor CAR-T therapy. Studies exploring mechanisms of resistance or failure of InO are ongoing but modulation or loss CD22 expression, alternative CD22 splicing, and high Bcl-2 expression have been implicated. In this review, we will summarize the currently available data on InO, with an emphasis on pediatric trials, and explore future directions including combinatorial therapy.

Harnessing the Immune System: Current and Emerging Immunotherapy Strategies for Pediatric Acute Lymphoblastic Leukemia

Treatment for relapsed acute lymphoblastic leukemia (ALL) in children and young adults continues to evolve. Despite optimization of cytotoxic chemotherapeutic approaches and risk-adapted therapy, about 12% of pediatric patients still relapse, and survival rates in this population remain poor. Salvage therapy for relapsed patients continues to be challenging as attempts to further intensify chemotherapy have resulted in excessive toxicity without improving outcomes. Immunotherapy has profoundly impacted the landscape of relapsed ALL by harnessing the patient's immune system to target and eliminate leukemia cells. In this review, we provide an overview and summary of immunotherapy agents that have been approved and remain under investigation for children, including blinatumomab, inotuzumab, daratumomab, and chimeric antigen receptor T-cell therapy. We discuss the landmark clinical trials that have revolutionized the field and provide an update on ongoing clinical trials involving these agents for children in the relapsed and upfront setting. The incorporation of these novel immunotherapies into ALL treatment, either as monotherapy or in combination with cytotoxic chemotherapy, has demonstrated promising potential to augment outcomes while decreasing toxicity. However, we also highlight the many challenges we still face and the research critically needed to achieve our goals for cure in children.

Diagnosis and management of adult central nervous system leukemia

Central nervous system leukemia (CNSL) is a prominent infiltration reason for therapy failing in acute leukemia. Recurrence rates and the prognosis have alleviated with current prophylactic regimens. However, the accurate stratification of relapse risk and treatment regimens for relapsed or refractory patients remain clinical challenges yet to be solved. Recently, with hematopoietic stem cell transplantation (HSCT) and chimeric antigen receptor-T (CAR-T) cellular therapy showing encouraging effects in some CNSL patients, advances in treating CNSL have already been reported. The development of molecular targeted agents as well as antibody-based drugs will provide patients with more personalized treatment. This article summarized recent research developments about risk factors, diagnosis, prevention, and treatment in adults with CNSL.

Sequencing antigen-targeting antibodies and cellular therapies in adults with relapsed/refractory B-cell acute lymphoblastic leukemia

The recent approvals of four CD19-or CD22-targeted therapies for B-cell acute lymphoblastic leukemia (B-ALL) have transformed the treatment of relapsed/refractory (r/r) disease. Adults with r/r B-ALL are usually eligible for all options, but there are no studies directly comparing these agents, and the treating physician must decide which to select. Each therapy has notable activity as a single agent but has limitations in particular settings, and the optimal choice varies. These therapies can be complementary and used either sequentially or concomitantly. Here, we review the current landscape of antigen-targeted therapies for r/r B-ALL and discuss considerations for their use.

Mechanisms of ADC Toxicity and Strategies to Increase ADC Tolerability

Anti-cancer antibody-drug conjugates (ADCs) aim to expand the therapeutic index of traditional chemotherapy by employing the targeting specificity of monoclonal antibodies (mAbs) to increase the efficiency of the delivery of potent cytotoxic agents to malignant cells. In the past three years, the number of ADCs approved by the Food and Drug Administration (FDA) has tripled. Although several ADCs have demonstrated sufficient efficacy and safety to warrant FDA approval, the clinical use of all ADCs leads to substantial toxicity in treated patients, and many ADCs have failed during clinical development due to their unacceptable toxicity profiles. Analysis of the clinical data has demonstrated that dose-limiting toxicities (DLTs) are often shared by different ADCs that deliver the same cytotoxic payload, independent of the antigen that is targeted and/or the type of cancer that is treated. DLTs are commonly associated with cells and tissues that do not express the targeted antigen (i.e., off-target toxicity), and often limit ADC dosage to levels below those required for optimal anti-cancer effects. In this manuscript, we review the fundamental mechanisms contributing to ADC toxicity, we summarize common ADC treatment-related adverse events, and we discuss several approaches to mitigating ADC toxicity.

Switching from salvage chemotherapy to immunotherapy in adult B-cell acute lymphoblastic leukemia

About one-half of adults with acute B-cell lymphoblastic leukemia (B-ALL) who do not achieve molecular complete remission or who subsequently relapse are not cured by current chemo- or targeted therapies. Previously, the sole therapeutic option for such persons was a hematopoietic stem cell transplant. Recently, several immune therapies including monoclonal antibodies, bispecific T-cell engagers (BiTEs), antibody-drug conjugates (ADCs), and chimeric antigen receptor T-cells (CARs) have been shown safe and effective in this setting. In this manuscript, we summarize data on US FDA-approved immune therapies of advanced adult B-ALL including rituximab, blinatumomab, inotuzumab ozogamicin, tisagenlecleucel and brexucabtagene autoleucel. We consider the results of clinical trials focusing on efficacy, safety, and quality of life (QoL). Real-world evidence is presented as well. We also briefly discuss pharmacodynamics, pharmacokinetics, and pharmacoeconomics followed by risk-benefit analyses. Lastly, we present future directions of immune therapies for advanced B-ALL in adults.

Monoclonal antibodies: new chance in the management of B-cell acute lymphoblastic leukemia

OBJECTIVES

This review aims to see the progress of several clinically-used monoclonal antibodies in treating ALL patients and how they improved patients' outcomes.

METHODS

We searched Web of Science, Elsevier and PubMed for relevant published studies, and summarized eligible evidence on the management of newly-diagnosed and relapsed or refractory ALL with monoclonal antibodies. Ongoing trials were identified from ClinicalTrials.gov.

RESULTS

Rituximab, an anti-CD20 monoclonal antibody, prolonged patients' complete remission duration and overall survival when combined with hyper-CVAD regimen. Another anti-CD20 monoclonal antibody, Ofatumumab, was reported to have similar benefits. Blinatumomab allows endogenous CD3-positive cytotoxic T cells to target and eliminate CD19-positive blasts. FDA has approved its efficacy in patients with R/R B-ALL and eliminating minimal residual disease (MRD). It serves as a bridge to eradicate MRD before transplantation, and may also be a new choice for patients unable to undergo transplantation. An anti-CD22 monoclonal antibody named Inotuzumab Ozogamicin showed great improvement in patients' outcome, but its toxicity to liver is also worthy of our attention.

CONCLUSION

Monoclonal antibodies are proven to be a promising immunotherapeutic strategy to improve ALL patients' outcome in the long term. There's still a need for individualized treatment with effective and well-tolerated medicines.Trial registration: ClinicalTrials.gov identifier: NCT01363128.Trial registration: ClinicalTrials.gov identifier: NCT01466179.Trial registration: ClinicalTrials.gov identifier: NCT02013167.Trial registration: ClinicalTrials.gov identifier: NCT02000427.Trial registration: ClinicalTrials.gov identifier: NCT01564784.Trial registration: ClinicalTrials.gov identifier: NCT03677596.Trial registration: ClinicalTrials.gov identifier: NCT01363297.Trial registration: ClinicalTrials.gov identifier: NCT02981628.Trial registration: ClinicalTrials.gov identifier: NCT03094611.Trial registration: ClinicalTrials.gov identifier: NCT01371630.Trial registration: ClinicalTrials.gov identifier: NCT04224571.Trial registration: ClinicalTrials.gov identifier: NCT02458014.Trial registration: ClinicalTrials.gov identifier: NCT04546399.Trial registration: ClinicalTrials.gov identifier: NCT02879695.Trial registration: ClinicalTrials.gov identifier: NCT03913559.Trial registration: ClinicalTrials.gov identifier: NCT03441061.Trial registration: ClinicalTrials.gov identifier: NCT03739814.Trial registration: ClinicalTrials.gov identifier: NCT02877303.Trial registration: ClinicalTrials.gov identifier: NCT03698552.Trial registration: ClinicalTrials.gov identifier: NCT04601584.Trial registration: ClinicalTrials.gov identifier: NCT04684147.Trial registration: ClinicalTrials.gov identifier: NCT04681105.

Updates in the Management of Relapsed and Refractory Acute Lymphoblastic Leukemia: An Urgent Plea for New Treatments Is Being Answered!

The treatment of acute lymphoblastic leukemia (ALL) has dramatically changed over the past three decades. However, relapsed and/or refractory ALL still remains with a very low survival and high morbidity associated with its treatment. Here, we will review the outstanding progress that has been made in the treatment of relapsed and/or refractory ALL and discuss future directions and challenges that require further investigation.

Antibody-drug conjugates: Resurgent anticancer agents with multi-targeted therapeutic potential

Antibody-drug conjugates (ADCs) constitute a relatively new group of anticancer agents, whose first appearance took place about two decades ago, but a renewed interest occurred in recent years, following the success of anti-cancer immunotherapy with monoclonal antibodies. Indeed, an ADC combines the selectivity of a monoclonal antibody with the cell killing properties of a chemotherapeutic agent (payload), joined together through an appropriate linker. The antibody moiety targets a specific cell surface antigen expressed by tumor cells and/or cells of the tumor microenvironment and acts as a carrier that delivers the cytotoxic payload within the tumor mass. Despite advantages in terms of selectivity and potency, the development of ADCs is not devoid of challenges, due to: i) low tumor selectivity when the target antigens are not exclusively expressed by cancer cells; ii) premature release of the cytotoxic drug into the bloodstream as a consequence of linker instability; iii) development of tumor resistance mechanisms to the payload. All these factors may result in lack of efficacy and/or in no safety improvement compared to unconjugated cytotoxic agents. Nevertheless, the development of antibodies engineered to remain inert until activated in the tumor (e.g., antibodies activated proteolytically after internalization or by the acidic conditions of the tumor microenvironment) together with the discovery of innovative targets and cytotoxic or immunomodulatory payloads, have allowed the design of next-generation ADCs that are expected to possess improved therapeutic properties. This review provides an overview of approved ADCs, with related advantages and limitations, and of novel targets exploited by ADCs that are presently under clinical investigation.

OUP accepted manuscript

BCR-ABL1 kinase inhibitors have improved the prognosis of Philadelphia-chromosome-positive (Ph⁺)-acute lymphoblastic leukemia (ALL). Ph-like (or BCR-ABL1-like) ALL does not express BCR-ABL1 but commonly harbors other genomic alterations of signaling molecules that may be amenable to therapy. Here, we report a case with a NUP214-ABL1 fusion detected at relapse by multiplexed, targeted RNA sequencing. It had escaped conventional molecular work-up at diagnosis, including cytogenetic analysis and fluorescence in situ hybridization for ABL1 rearrangements. The patient had responded poorly to initial multi-agent chemotherapy and inotuzumab immunotherapy at relapse before the fusion was revealed. The addition of dasatinib targeting NUP214-ABL1 to inotuzumab resulted in complete molecular remission, but recurrence occurred rapidly with dasatinib alone. However, deep molecular remission was recaptured with a combination of blinatumomab and ponatinib, so he could proceed to allotransplantation. This case illustrates that next-generation sequencing approaches designed to discover cryptic gene fusions can benefit patients with Ph-like ALL.

KTE-X19 for relapsed or refractory adult B-cell acute lymphoblastic leukaemia: phase 2 results of the single-arm, open-label, multicentre ZUMA-3 study

BACKGROUND

Despite treatment with novel therapies and allogeneic stem-cell transplant (allo-SCT) consolidation, outcomes in adult patients with relapsed or refractory B-precursor acute lymphoblastic leukaemia remain poor, underlining the need for more effective therapies.

METHODS

We report the pivotal phase 2 results of ZUMA-3, an international, multicentre, single-arm, open-label study evaluating the efficacy and safety of the autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy KTE-X19 in adult patients with relapsed or refractory B-precursor acute lymphoblastic leukaemia. Patients were enrolled at 25 sites in the USA, Canada, and Europe. Eligible patients were aged 18 years or older, with Eastern Cooperative Oncology Group performance status of 0-1, and morphological disease in the bone marrow (>5% blasts). After leukapheresis and conditioning chemotherapy, patients received a single KTE-X19 infusion (1 × 106 CAR T cells per kg bodyweight). The primary endpoint was the rate of overall complete remission or complete remission with incomplete haematological recovery by central assessment. Duration of remission and relapse-free survival, overall survival, minimal residual disease (MRD) negativity rate, and allo-SCT rate were assessed as secondary endpoints. Efficacy and safety analyses were done in the treated population (all patients who received a dose of KTE-X19). This study is registered with ClinicalTrials.gov, NCT02614066.

FINDINGS

Between Oct 1, 2018, and Oct 9, 2019, 71 patients were enrolled and underwent leukapheresis. KTE-X19 was successfully manufactured for 65 (92%) patients and administered to 55 (77%). The median age of treated patients was 40 years (IQR 28-52). At the median follow-up of 16·4 months (13·8-19·6), 39 patients (71%; 95% CI 57-82, p<0·0001) had complete remission or complete remission with incomplete haematological recovery, with 31 (56%) patients reaching complete remission. Median duration of remission was 12·8 months (95% CI 8·7-not estimable), median relapse-free survival was 11·6 months (2·7-15·5), and median overall survival was 18·2 months (15·9-not estimable). Among responders, the median overall survival was not reached, and 38 (97%) patients had MRD negativity. Ten (18%) patients received allo-SCT consolidation after KTE-X19 infusion. The most common adverse events of grade 3 or higher were anaemia (27 [49%] patients) and pyrexia (20 [36%] patients). 14 (25%) patients had infections of grade 3 or higher. Two grade 5 KTE-X19-related events occurred (brain herniation and septic shock). Cytokine release syndrome of grade 3 or higher occurred in 13 (24%) patients and neurological events of grade 3 or higher occurred in 14 (25%) patients.

INTERPRETATION

KTE-X19 showed a high rate of complete remission or complete remission with incomplete haematological recovery in adult patients with relapsed or refractory B-precursor acute lymphoblastic leukaemia, with the median overall survival not reached in responding patients, and a manageable safety profile. These findings indicate that KTE-X19 has the potential to confer long-term clinical benefit to these patients.

FUNDING

Kite, a Gilead Company.

Optimizing the treatment of acute lymphoblastic leukemia in younger and older adults: new drugs and evolving paradigms

In the past decade, the available treatments for patients with acute lymphoblastic leukemia (ALL) have rapidly expanded, in parallel with an increased understanding of the genomic features that impact the disease biology and clinical outcomes. With the development of the anti-CD22 antibody-drug conjugate inotuzumab ozogamicin, the CD3-CD19 bispecific T-cell engager antibody blinatumomab, CD19 chimeric antigen receptor T-cell therapy, and the potent BCR-ABL1 tyrosine kinase inhibitor ponatinib, the outlook of ALL in both younger and older adults has substantially improved. The availability of highly effective drugs raised important questions concerning the optimal combination and sequence of these agents, their incorporation into frontline regimens, and the role of hematopoietic stem cell transplantation. In this review, we discuss the rapidly evolving paradigms in the treatment of ALL, highlighting both established and effective regimens, as well as promising new therapies that are being evaluated in ongoing clinical trials. We specifically focus on novel combination regimens in both the frontline and salvage settings that are leading to new standards of care in the treatment of ALL.

Current Approaches to Philadelphia Chromosome-Positive B-Cell Lineage Acute Lymphoblastic Leukemia: Role of Tyrosine Kinase Inhibitor and Stem Cell Transplant

PURPOSE OF REVIEW

Over the past two decades, tyrosine kinase inhibitors (TKIs) have changed the management of patients with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL), and this has led to significant improvement in their outcome. In this review, we will provide an overview of the current understanding of treatment of Ph+ ALL focusing on TKIs, alloHSCT, and novel therapies.

RECENT FINDINGS

The advent of more potent TKIs and the novel therapeutic options including blinatumomab, inotuzumab ozogamicin, and CD19 CAR-T therapy has changed the role of allogeneic hematopoietic stem cell transplant (alloHSCT) and intensive chemotherapy. To avoid toxicity from the historical treatment strategies, a more individualized, targeted approach to therapy including detection and monitoring of measurable residual disease (MRD) has become of interest. The treatment of patients with Ph+ ALL has been rapidly evolving with a more individualized, targeted treatment and use of TKIs and novel therapy.

Inotuzumab Ozogamicin for Relapsed/Refractory Acute Lymphoblastic Leukemia in the INO-VATE Trial: CD22 Pharmacodynamics, Efficacy, and Safety by Baseline CD22

PURPOSE

We assessed the relationship between cluster of differentiation-22 (CD22) expression and outcomes of inotuzumab ozogamicin versus standard of care (SC) in INO-VATE (NCT01564784).

PATIENTS AND METHODS

Adults with relapsed/refractory B-cell precursor CD22-positive (by local or central laboratory) acute lymphoblastic leukemia were randomized to inotuzumab ozogamicin (n = 164) or SC (n = 162). Outcomes were analyzed by baseline CD22 positivity (percentage of leukemic blasts CD22 positive, ≥90% vs. <90%) and CD22 receptor density [molecules of equivalent soluble fluorochrome (MESF), quartile analysis].

RESULTS

Most patients had high (≥90%) CD22 positivity per central laboratory. The response rate was significantly higher with inotuzumab ozogamicin versus SC. Minimal/measurable residual disease negativity, duration of remission (DoR), progression-free survival, and overall survival (OS) were significantly better with inotuzumab ozogamicin versus SC in patients with CD22 positivity ≥90%. Fewer patients had CD22 positivity <90%; for whom, response rates were higher with inotuzumab ozogamicin versus SC, but DoR and OS appeared similar. Similar trends were evident in quartile analyses of CD22 MESF and CD22 positivity per local laboratory. Among inotuzumab ozogamicin-responding patients with subsequent relapse, decrease in CD22 positivity and receptor density was evident, but not the emergence of CD22 negativity. Rates of grade ≥3 hematologic adverse events (AEs) were similar and hepatobiliary AEs rate was higher for inotuzumab ozogamicin versus SC. No apparent relationship was observed between the rates of hematologic and hepatic AEs and CD22 expression.

CONCLUSIONS

Inotuzumab ozogamicin demonstrated a favorable benefit-risk profile versus SC in patients with higher and lower CD22 expression. Patients with high CD22 expression and normal cytogenetics benefited the most from inotuzumab ozogamicin therapy.

Measurable residual disease affects allogeneic hematopoietic cell transplantation in Ph+ ALL during both CR1 and CR2

Although measurable residual disease (MRD) at the time of allogeneic hematopoietic cell transplantation (allo-HCT) has been reported to be an important prognostic factor for Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL) during first complete remission (CR1), the prognostic impact of MRD is unclear during second CR (CR2). To clarify the impact of MRD for both CR1 and CR2, we analyzed data from a registry database including 1625 adult patients with Ph+ ALL who underwent first allo-HCT during either CR1 or CR2 between 2002 and 2017. Adjusted overall and leukemia-free survival rates at 4 years were 71% and 64%, respectively, for patients undergoing allo-HCT during CR1 with MRD-, 55% and 43% during CR1 with MRD+, 51% and 49% during CR2 with MRD-, and 38% and 29% during CR2 with MRD+. Although survival rates were significantly better among patients with CR1 MRD- than among patients with CR2 MRD-, no significant difference was observed in survival rate between patients with CR1 MRD+ and CR2 MRD-. Relapse rates after 4 years were 16% in patients with CR1 MRD-, 29% in CR1 MRD+, 21% in patients with CR2 MRD-, and 46% in patients with CR2 MRD+. No significant difference was identified in relapse rate between patients with CR1 MRD- and CR2 MRD-. CR2 MRD- was not a significant risk factor for relapse in multivariate analysis (hazard ratio, 1.26; 95% confidence interval, 0.69-2.29; P = .45 vs CR1 MRD-). MRD at time of allo-HCT was an important risk factor in patients with Ph+ ALL during both CR1 and CR2.

Model-Informed Therapeutic Dose Optimization Strategies for Antibody-Drug Conjugates in Oncology: What Can We Learn From US Food and Drug Administration-Approved Antibody-Drug Conjugates?

Antibody–drug conjugates (ADCs) combine the specificity of an antibody with the cytotoxicity of a chemical agent. They represent a rapidly evolving area of oncology drug development and hold significant promise. There are currently nine ADCs on the market, more than half of which gained US Food and Drug Administration approval more recently, since 2019. Despite their enormous promise, the therapeutic window for these ADCs remains relatively narrow, especially when compared with other oncology drugs, such as targeted therapies or checkpoint inhibitors. In this review, we provide a detailed overview of the five dosing regimen optimization strategies that have been leveraged to broaden the therapeutic window by mitigating the safety risks while maintaining efficacy. These include body weight cap dosing; treatment duration capping; dose schedule (e.g., dosing frequency and dose fractionation); response‐guided dosing recommendations; and randomized dose‐finding. We then discuss how the lessons learned from these studies can inform ADC development going forward. Informed application of these dosing strategies should allow researchers to maximize the safety and efficacy for next‐generation ADCs.

The clinical development of antibody-drug conjugates - lessons from leukaemia

Advances in our understanding of cancer biology have enabled drug development to progress towards better targeted therapies that are both more effective and safer owing to their lack of off-target toxicities. In this regard, antibody-drug conjugates (ADCs), which have the potential to combine the selectivity of therapeutic antibodies with the cytotoxicity of highly toxic small molecules, are a rapidly developing drug class. The complex and unique structure of an ADC, composed of a monoclonal antibody conjugated to a potent cytotoxic payload via a chemical linker, is designed to selectively target a specific tumour antigen. The success of an ADC is highly dependent on the specific properties of its components, all of which have implications for the stability, cytotoxicity, pharmacokinetics and antitumour activity of the ADC. The development of therapeutic ADCs, including gemtuzumab ozogamicin and inotuzumab ozogamicin, provided great knowledge of the refinements needed for the optimization of such agents. In this Review, we describe the key components of ADC structure and function and focus on the clinical development and subsequent utilization of two leukaemia-directed ADCs - gemtuzumab ozogamicin and inotuzumab ozogamicin - as well as on the mechanisms of resistance and predictors of response to these two agents.

Monoclonal Antibodies: A Prospective and Retrospective View

BACKGROUND

Monoclonal Antibodies (mAbs) represent one of the most important classes of biotherapeutic agents. They are used to cure many diseases, including cancer, autoimmune diseases, cardiovascular diseases, angiogenesis-related diseases and, more recently also haemophilia. They can be highly varied in terms of format, source, and specificity to improve efficacy and to obtain more targeted applications. This can be achieved by leaving substantially unchanged the basic structural components for paratope clustering.

OBJECTIVES

The objective was to trace the most relevant findings that have deserved prestigious awards over the years, to report the most important clinical applications and to emphasize their latest emerging therapeutic trends.

RESULTS

We report the most relevant milestones and new technologies adopted for antibody development. Recent efforts in generating new engineered antibody-based formats are briefly reviewed. The most important antibody-based molecules that are (or are going to be) used for pharmacological practice have been collected in useful tables.

CONCLUSION

The topics here discussed prove the undisputed role of mAbs as innovative biopharmaceuticals molecules and as vital components of targeted pharmacological therapies.

Recent Advances in Managing Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is characterized by chromosomal translocations and somatic mutations that lead to leukemogenesis. The incorporation of pediatric-type regimens has improved survival in young adults, and the incorporation of tyrosine kinase inhibitors for patients with Philadelphia chromosome-positive disease has led to further improvements in outcomes. However, older patients often have poor-risk biology and reduced tolerance to chemotherapy, leading to lower remission rates and overall survival. Regardless of age, patients with relapsed or refractory ALL have extremely poor outcomes. The advent of next-generation sequencing has facilitated the revolution in understanding the genetics of ALL. New genetic risk stratification together with the ability to measure minimal residual disease, leukemic blasts left behind after cytotoxic chemotherapy, has led to better tools to guide postremission approaches-that is, consolidation chemotherapy or allogeneic stem cell transplantation. In this article, we discuss the evolving and complex genetic landscape of ALL and the emerging therapeutic options for patients with relapsed/refractory ALL and older patients with ALL.

Efficacy and Safety of Inotuzumab Ozogamicin (CMC-544) for the Treatment of Relapsed/Refractory Acute Lymphoblastic Leukemia and Non-Hodgkin Lymphoma: A Systematic Review and Meta-Analysis

INTRODUCTION

The purpose of this systematic review and meta-analysis was to evaluate the efficacy and safety of inotuzumab ozogamicin (INO) in patients with relapsed/refractory acute lymphocytic leukemia (ALL) and non-Hodgkin lymphoma (NHL).

MATERIALS AND METHODS

Databases (PubMed, EMBASE, and Cochrane databases) were searched through April 4, 2020. Outcome measures of efficacy covered complete remission (CR) rates and minimal residual disease response rates. Safety was evaluated by hepatic venous obstructive disease/sinus obstructive syndrome and grade ≥ 3 hematologic adverse events. We also evaluated the quality of enrolled studies by the Newcastle-Ottawa Quality Assessment Scale.

RESULTS

A total of 12 studies involving 644 patients were included. The summary estimates of the CR and minimal residual disease response rates for patients with ALL were 67% (95% confidence interval [CI], 61%-73%) and 45% (95% CI, 37%-53%) of patients with NHL. The pooled CR rate was 28% (95% CI, 15%-47%). Thrombocytopenia and neutropenia were the most common adverse events. In patients receiving INO, venous obstructive disease/sinus obstructive syndrome, grade ≥ 3 thrombocytopenic events, grade ≥ 3 neutropenic events of the pooled estimated incidence were 8% (95% CI, 5%-14%), 29% (95% CI, 20%-39%), and 48% (95% CI, 38%-57%).

CONCLUSIONS

According to our study, INO was effective in the treatment of relapsed/refractory ALL and NHL with limited adverse effects. High-quality randomized controlled trials and extensive follow-up are pending to confirm and update the results of this analysis in the future.

Role of blinatumomab, inotuzumab, and CAR T-cells: Which to choose and how to sequence for patients with relapsed disease

Recent approval of several novel agents has dramatically improved outcomes for patients with relapsed and refractory (R/R) B-cell acute lymphoblastic leukemia. Blinatumomab, a bi-specific T-cell engager targeted to CD3 and CD19, inotuzumab ozogamicin (InO), an antibody-drug conjugate to CD22, and tisagenlecleucel, a CD19 chimeric antigen receptor T-cell with a 4-1BB costimulatory domain, have all demonstrated impressive response rates in R/R B-ALL as compared to historic controls. However, important considerations when choosing among these novel agents include clinical features that may impact efficacy, such as relative disease burden, antigen expression, and T-cell function, as well as patient and disease characteristics that may contribute to risk of toxicity. In addition, suitability of the patient for hematopoietic stem cell transplant (HSCT) as well as patient preference must also be considered. This review will focus on factors to weigh when choosing an agent in the setting of R/R disease and important challenges moving forward.

Efficacy of inotuzumab ozogamicin in patients with Philadelphia chromosome-positive relapsed/refractory acute lymphoblastic leukemia

BACKGROUND

Patients with relapsed/refractory (R/R) Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) have a poor prognosis and limited treatment options.

METHODS

The efficacy of inotuzumab ozogamicin (InO), a humanized anti-CD22 monoclonal antibody conjugated to the cytotoxic antibiotic calicheamicin, was evaluated in R/R ALL patients in the phase 1/2 study 1010 (NCT01363297) and open-label, randomized, phase 3 study 1022 (INO-VATE; NCT01564784). This analysis focused specifically on Ph+ R/R ALL patients. In study 1022, Ph+ patients were randomly assigned 1:1 to InO (n = 22) or standard intensive chemotherapy (SC) (n = 27) and 16 Ph+ patients in study 1010 received InO.

RESULTS

In study 1022, rates of complete remission/complete remission with incomplete hematologic recovery (CR/CRi) and minimal residual disease (MRD) negativity (patients achieving CR/CRi) were higher with InO (CR/CRi = 73%; MRD = 81%) versus SC (CR/CRi = 56%; MRD = 33%). The corresponding rates in study 1010 were 56% (CR/CRi) and 100% (MRD). The hematopoietic stem cell transplantation (HSCT) rate in study 1022 was 41% versus 19% for InO versus SC; however, there was no benefit in overall survival (median OS: 8.7 vs 8.4 months; hazard ratio, 1.17 [95% CI, 0.64-2.14]). The probability of being event-free (progression-free survival) at 12 months was greater with InO versus SC (20.1% vs 4.8%).

CONCLUSION

Given the substantial improvement in responses and rates of HSCT, InO is an important treatment option for patients with R/R Ph+ ALL. Future studies need to consider better characterization of disease characteristics, more sensitive MRD measurements, MRD-directed therapy before HSCT, and potentially combination therapies, including tyrosine kinase inhibitors.

Combination of clofarabine, etoposide, and cyclophosphamide in adult relapsed/refractory acute lymphoblastic leukemia: a phase 1/2 dose-escalation study by the Japan Adult Leukemia Study Group

This phase 1/2 study aimed to identify the maximum tolerated dose, the recommended phase 2 dose (RP2D), and efficacy of the clofarabine, etoposide, and cyclophosphamide combination regimen in adult patients with relapsed/refractory acute lymphoblastic leukemia (ALL). Patients aged ≥ 15 years with relapsed/refractory ALL were enrolled. Escalating doses of clofarabine (20-30 mg/m²/day × 5 days), etoposide (50-100 mg/m²/day × 5 days), and cyclophosphamide (200-440 mg/m²/day × 5 days) were administered. Dose-limiting toxicity was defined as Grade 3 or more non-hematological toxicities and others. A total of 18 patients (B-ALL; n = 13, T-ALL; n = 5) were recruited in phase 1; however, the protocol was amended to close study without proceeding to phase 2. Three patients were enrolled in cohort 1, three in cohort 2, six in cohort 3, and six in cohort 4. The RP2D of clofarabine, etoposide, and cyclophosphamide was 30, 100, and 440 mg/m² daily, respectively. Complete remission (CR) was achieved in four patients (22%) and CR without platelet recovery in four patients (22%), with an overall response rate of 44%. The RP2D of the combination therapy was successfully determined in this study.

Monoclonal antibodies in frontline acute lymphoblastic leukemia

The recent development of monoclonal antibodies targeting CD19, CD20, and CD22 has significantly improved long-term survival in patients with acute lymphoblastic leukemia (ALL), both in the frontline and relapsed and refractory setting. The incorporation of CD20 monoclonal antibodies (e.g. rituximab) has improved cure rates from 35% to 50% in those with precursor B-cell ALL and from 40 to 80% in those with Burkitt leukemia. More novel antibodies, such as drug conjugates antibodies (e.g. inotuzumab ozogamicin) and bispecific T-cell engagers (e.g. blinatumomab), have shown significant promise in improving outcomes in the relapsed and refractory setting and are currently being studied in the frontline setting, with hopes to further improve long-term outcomes. In this chapter, we will review the role of monoclonal antibodies and how the incorporation of these agents has revolutionized and changed the treatment management of ALL in the frontline setting.

Evaluating Blinatumomab for the Treatment of Relapsed/Refractory ALL: Design, Development, and Place in Therapy

Although adults with B-cell acute lymphoblastic leukemia (B-ALL) achieve high complete remission (CR) rates following treatment with intensive multi-agent chemotherapy regimens, up to two-thirds of these patients eventually relapse. Unfortunately, adults with relapsed or refractory (R/R) B-ALL have a poor prognosis, with variable responses to salvage chemotherapy regimens and allogeneic stem cell transplant. As such, the need to develop effective and well-tolerated treatments for this patient population has been of paramount importance over the past decade. In this regard, treatment options for R/R B-ALL patients have expanded considerably over a relatively short period of time, with the approvals of blinatumomab, inotuzumab ozogamicin and tisagenlecleucel occurring within only the past six years. Blinatumomab, a CD19 x CD3 bispecific T-cell engager (BiTE) was the first of these immune therapies to receive approval, and for many patients, is used as first-line salvage therapy. A number of large clinical trials have demonstrated improved progression-free survival and overall survival for R/R B-ALL patients receiving blinatumomab as compared to those receiving conventional salvage chemotherapy. In addition to being approved for both Philadelphia chromosome-negative and Philadelphia chromosome-positive R/R B-ALL, blinatumomab is also the only ALL therapy that carries approval for the treatment of measurable residual disease (MRD). Although blinatumomab has changed the therapeutic landscape for adults with R/R B-ALL, a number of important clinical considerations and questions remain, including the potential role of blinatumomab in the frontline setting, mechanisms of resistance, optimal goal MRD level, the role of transplant following MRD clearance, the optimal place for blinatumomab in the context of other recently approved immune-mediated therapies, and real world outcomes for patients treated outside the context of clinical trials. These issues are the focus of ongoing studies, which will hopefully inform future clinical practice regarding the utility of blinatumomab in the treatment of B-ALL patients.

Immunotherapy in Pediatric B-Cell Acute Lymphoblastic Leukemia: Advances and Ongoing Challenges

Leukemia, most commonly B-cell acute lymphoblastic leukemia (B-ALL), accounts for about 30% of childhood cancer diagnoses. While there have been dramatic improvements in childhood ALL outcomes, certain subgroups-particularly those who relapse-fare poorly. In addition, cure is associated with significant short- and long-term side effects. Given these challenges, there is great interest in novel, targeted approaches to therapy. A number of new immunotherapeutic agents have proven to be efficacious in relapsed or refractory disease and are now being investigated in frontline treatment regimens. Blinatumomab (a bispecific T-cell engager that targets cluster of differentiation [CD]-19) and inotuzumab ozogamicin (a humanized antibody-drug conjugate to CD22) have shown the most promise. Chimeric antigen receptor T (CAR-T) cells, a form of adoptive immunotherapy, rely on the transfer of genetically modified effector T cells that have the potential to persist in vivo for years, providing ongoing long-term disease control. In this article, we discuss the clinical biology and treatment of B-ALL with an emphasis on the role of immunotherapy in overcoming the challenges of conventional cytotoxic therapy. As immunotherapy continues to move into the frontline of pediatric B-ALL therapy, we also discuss strategies to address unique side effects associated with these agents and efforts to overcome mechanisms of resistance to immunotherapy.

Hepatic veno-occlusive disease in allogeneic stem cell transplant recipients with prior exposure to gemtuzumab ozogamicin or inotuzumab ozogamicin

Hepatic veno-occlusive disease (VOD/sinusoidal obstructive syndrome) represents a constellation of clinical findings including right upper quadrant pain, jaundice, hepatomegaly, and ascites. In the post-hematopoietic stem cell transplant (SCT) setting, the reported incidence has been 10-15%, with severe VOD historically resulting in high mortality rates. Novel agents including calicheamicin conjugated with CD33 (gemtuzumab ozogamicin; GO) and CD22 (inotuzumab ozogamicin; InO) are increasingly used for the treatment of acute myeloid leukemia and acute lymphoblastic leukemia, respectively. Both GO and InO are highly active, but also have unique hepatotoxicity profiles, including a higher risk of VOD in recipients of SCT. Introduction of GO and InO into pre-SCT leukemia management adds additional complexity to SCT patient selection and toxicity monitoring. In this article, we describe and review the risks and management associated with VOD in SCT recipients exposed to GO and InO.

New monoclonal antibodies and tyrosine kinase inhibitors in B-cell acute lymphoblastic leukemia

Patients with acute lymphoblastic leukemia (ALL) are characterized by an unfavorable outcome in the majority of adult cases. Several clinical trials have confirmed the usefulness of a pediatric-type therapy applied to adult patients. Adults present with higher risk features at diagnosis that predispose them to chemotherapy resistance and disease relapse after an initial achievement of complete remission. The recent introduction of novel immune-targeted therapies, including monoclonal antibodies (MoAbs) targeting B cell-associated antigens such as CD19 (blinatumumab) and CD22 (inotuzumab), tyrosine kinase inhibitors targeting BCR-ABL1 tyrosine kinase, bispecific antibodies and chimeric antigen receptor T- cell therapy (CAR-T), circumvent B-ALL cell chemo-refractoriness through novel mechanisms of action, potentially eradicating minimal residual disease (MRD) and enabling more patients to receive allogeneic hematopoietic stem cell transplantation and to achieve a better clinical outcome.

Characterization of the Relationship of Inotuzumab Ozogamicin Exposure With Efficacy and Safety End Points in Adults With Relapsed or Refractory Acute Lymphoblastic Leukemia

Inotuzumab ozogamicin (InO), an anti‐CD22 monoclonal antibody conjugated to calicheamicin, is approved in Europe and the United States for treatment of adults with relapsed or refractory acute lymphoblastic leukemia (ALL). Population analyses were performed to evaluate the relationship between InO exposure and efficacy and safety end points in patients with ALL. The probability of achieving complete remission/complete remission with incomplete hematologic recovery (CR/CRi) and minimal residual disease (MRD)‐negativity for InO relative to chemotherapy was also investigated. Data from study 1010 (NCT01363297) and INO‐VATE (NCT01564784) were pooled for exposure–response (InO, n = 234) and treatment–response (InO, n = 234; chemotherapy, n = 143) analyses. The analyses demonstrated that InO exposure was significantly correlated with achieving CR/CRi and MRD‐negativity, as well as with hepatic event adjudication board‐reported veno‐occlusive disease/sinusoidal obstruction. Patients with ALL treated with InO had significantly greater odds of achieving CR/CRi (7‐times higher) and MRD‐negativity (13‐times higher) than those receiving chemotherapy.

Antibody-drug conjugates for multiple myeloma

Introduction: Antibody-drug conjugates (ADC) are a new class of treatment for multiple myeloma (MM) patients, delivering a potent cytotoxic agent directly to the myeloma cell. The target is defined by the specificity of the monoclonal antibody which is linked to the cytotoxic agent. This mechanism of action minimizes bystander cell injury and allows a favorable therapeutic window.Areas covered: This review describes the rationale, pre- and clinical data for ADCs that have been and are currently in development for MM. As the treatment landscape for MM rapidly evolves, the treatment paradigm and a description of novel agents in development including immunotherapies are provided to understand how ADCs may fit in the pathway.Expert opinion: ADCs have a significant potential for the treatment for MM. As they are 'off the shelf' treatments, they can be used across nearly all MM treatment centers and to a wide range of patients. Some ADCs have specific adverse events that may require specialist input to optimally manage. The most clinically advanced ADC is belantamab mafodotin which has demonstrated clinically meaningful responses in patients with heavily pre-treated MM. Additionally, it is being combined with standard of care agents and at earlier lines of treatment.

Inotuzumab ozogamicin for relapsed/refractory acute lymphoblastic leukemia: outcomes by disease burden

Adults with relapsed/refractory acute lymphoblastic leukemia (R/R ALL) have a poor prognosis, especially if disease burden is high. This post hoc analysis of the phase 3 INO-VATE trial examined the efficacy and safety of inotuzumab ozogamicin (InO) vs. standard of care chemotherapy (SC) among R/R ALL patients with low, moderate, or high disease burden, respectively, defined as bone marrow blasts (BMB) < 50% (n = 53 vs. 48), 50–90% (n = 79 vs. 83), and >90% (n = 30 vs. 30). Patients in the InO vs. SC arm with low, moderate, and high BMB%, respectively, had improved rates of complete remission/complete remission with incomplete hematologic recovery (74% vs. 46% [p = 0.0022], 75 vs. 27% [p < 0.0001], and 70 vs. 17% [p < 0.0001]), and improved overall survival (hazard ratio: 0.64 [p = 0.0260], 0.81 [p = 0.1109], and 0.60 [p = 0.0335]). Irrespective of BMB%, cytopenias were the most common treatment-emergent adverse events, and post-transplant veno-occlusive disease was more common with InO vs. SC. Patients with extramedullary disease or lymphoblastic lymphoma showed similar efficacy and safety outcomes. This favorable benefit-to-risk ratio of InO treatment irrespective of disease burden supports its use in challenging and high disease burden subpopulations. INO-VATE is registered at www.clinicaltrials.gov: #NCT01564784.

Acute lymphoblastic leukemia (ALL for short) is a type of blood cancer where the body makes too many immature white blood cells called lymphoblasts. This study involved people with ALL whose cancer had returned after, or stopped responding to, previous treatment. These people received either inotuzumab ozogamicin (InO for short) or standard chemotherapy. Researchers divided people into groups, based on the level of lymphoblast cells they had in their bone marrow (called disease burden): low, medium, or high disease burden. In this study, compared with people who received standard chemotherapy, people who received InO were more likely to have no signs of their cancer (called remission), live to the end of the study, and/or reach the end of the study without their cancer getting worse. The researchers saw these results across all disease burden groups. For people who received InO, those with high disease burden were equally as likely as those with low disease burden to achieve remission, and/or experience medical problems. For people who received standard chemotherapy, those with high disease burden were less likely than those with low disease burden to achieve remission. Further information in a plain language format is available in Supplementary Information (SI) Fig. S1.

Recent Advances in Adult Acute Lymphoblastic Leukemia

PURPOSE OF REVIEW

This article reviews the recent advances in the pathophysiology and management of acute lymphoblastic leukemia (ALL) in adults.

RECENT FINDINGS

Addition of rituximab to standard chemotherapy improves survival in the frontline treatment of B cell ALL, and measurable residual disease (MRD) is the most important prognostic factor. Tyrosine kinase inhibitors (TKI), particularly ponatinib, in combination with Hyper-CVAD significantly improve outcomes in Ph + ALL challenging the benefit of allogeneic stem cell transplant in first line for these patients. Blinatumomab, inotuzumab ozogamicin, and chimeric antigen receptor (CAR) T cells are better options than chemotherapy alone for the treatment of relapsed or refractory ALL. Combination of these agents with chemotherapy and their incorporation in the frontline setting show promises to improve cure rates of ALL. Development of monoclonal antibodies, CAR T, and potent TKI has improved the outcome of ALL. Advances in our understanding of ALL biology are expected to bring new therapeutic strategies in the upcoming years.

Using Pharmacology to Squeeze the Life Out of Childhood Leukemia, and Potential Strategies to Achieve Breakthroughs in Medulloblastoma Treatment

Eliminating cancer was once thought of as a war. This analogy is still apt today; however, we now realize that cancer is a much more formidable enemy than scientists originally perceived, and in some cases, it harbors a profound ability to thwart our best efforts to defeat it. However, before we were aware of the complexity of cancer, chemotherapy against childhood acute lymphoblastic leukemia (ALL) was successful because it applied the principles of pharmacology. Herein, we provide a historic perspective of the experience at St. Jude Children's Research Hospital. In 1962, when the hospital opened, fewer than 3% of patients experienced durable cure. Through judicious application of pharmacologic principles (e.g., combination therapy with agents using different mechanisms of action) plus appropriate drug scheduling, dosing, and pharmacodynamics, the survival of patients with ALL now exceeds 90%. We contrast this approach to treating ALL with the contemporary approach to treating medulloblastoma, in which genetics and molecular signatures are being used to guide the development of more-efficacious treatment strategies with minimal toxicity. Finally, we highlight the emerging technologies that can sustain and propel the collaborative efforts to squeeze the life out of these cancers. SIGNIFICANCE STATEMENT: Up until the early 1960s, chemotherapy for childhood acute lymphoblastic leukemia was mostly ineffective. This changed with the knowledge and implementation of rational approaches to combination therapy. Although the therapeutics of brain cancers such as medulloblastoma are not as refined (in part because of the blood-brain barrier obstacle), recent extraordinary advances in knowledge of medulloblastoma pathobiology has led to innovations in disease classification accompanied with strategies to improve therapeutic outcomes. Undoubtedly, additional novel approaches, such as immunological therapeutics, will open new avenues to further the goal of taming cancer.

Patient Selection Strategies to Maximize Therapeutic Index of Antibody-Drug Conjugates: Prior Approaches and Future Directions

Antibody-drug conjugates (ADC) are targeted agents that have shown promise in treating cancer. A central challenge in development of ADCs is the relatively narrow therapeutic index observed in clinical studies. Patient selection strategies based on expression of the target in tumors have the potential to maximize benefit and provide the best chance of clinical success; however, implementation of biomarker-driven trials can be difficult both practically and scientifically. We conducted a survey of recent clinical experience from early-phase ADC trials completed between 2000 and 2019 to evaluate the different approaches to patient selection currently being used and assess whether there is evidence that target expression is associated with clinical activity. Our analysis of patient selection strategies indicates that optimal trial design for early-stage trials should be based on multiple factors, including prevalence and heterogeneity of target expression among intent-to-treat patients, as well as biological factors influencing expression of cell surface and soluble target. To ensure a high probability of success, early implementation of patient selection strategies centered around target expression are pivotal to development of ADCs. In this review, we propose a strategic approach that can be applied for optimization of trial design.

Evolving therapy of adult acute lymphoblastic leukemia: state-of-the-art treatment and future directions

Recent years have witnessed major advances that have improved outcome of adults with acute lymphoblastic leukemia (ALL). The emergence of the concept of measurable residual disease has fine-tuned our prognostic models and guided our treatment decisions. The treatment paradigms of ALL have been revolutionized with the advent of tyrosine kinase inhibitors targeting BCR-ABL1, monoclonal antibodies targeting CD20 (rituximab), antibody-drug conjugates targeting CD22 (inotuzumab ozogamicin), bispecific antibodies (blinatumomab), and CD19 chimeric antigen receptor T cell therapy (tisagenlecleucel). These highly effective new agents are allowing for novel approaches that reduce reliance on intensive cytotoxic chemotherapy and hematopoietic stem cell transplantation in first remission. This comprehensive review will focus on the recent advances and future directions in novel therapeutic strategies in adult ALL.

Personalized therapy in pediatric high-risk B-cell acute lymphoblastic leukemia

Although cure rates for pediatric acute lymphoblastic leukemia (ALL) have now risen to more than 90%, subsets of patients with high-risk features continue to experience high rates of treatment failure and relapse. Recent work in minimal residual disease stratification and leukemia genomics have increased the ability to identify and classify these high-risk patients. In this review, we discuss this work to identify and classify patients with high-risk ALL. Novel therapeutics, which may have the potential to improve outcomes for these patients, are also discussed.

Acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia develops in both children and adults, with a peak incidence between 1 year and 4 years. Most acute lymphoblastic leukaemia arises in healthy individuals, and predisposing factors such as inherited genetic susceptibility or environmental exposure have been identified in only a few patients. It is characterised by chromosomal abnormalities and genetic alterations involved in differentiation and proliferation of lymphoid precursor cells. Along with response to treatment, these abnormalities are important prognostic factors. Disease-risk stratification and the development of intensified chemotherapy protocols substantially improves the outcome of patients with acute lymphoblastic leukaemia, particularly in children (1-14 years), but also in adolescents and young adults (15-39 years). However, the outcome of older adults (≥40 years) and patients with relapsed or refractory acute lymphoblastic leukaemia remains poor. New immunotherapeutic strategies, such as monoclonal antibodies and chimeric antigen receptor (CAR) T cells, are being developed and over the next few years could change the options for acute lymphoblastic leukaemia treatment.

Cutting to the Front of the Line: Immunotherapy for Childhood Acute Lymphoblastic Leukemia

Although many children and young adults with B-cell acute lymphoblastic leukemia (B-ALL) are cured with modern, risk-adapted chemotherapy regimens, 10% to 15% of patients will experience relapse or have refractory disease. Recent efforts to further intensify cytotoxic chemotherapy regimens in the frontline setting have failed as a result of excessive toxicity or lack of improvement in efficacy. As a result, novel approaches will be required to achieve cures in more newly diagnosed patients. Multiple immune-based therapies have demonstrated considerable efficacy in the setting of relapsed or refractory (R/R) disease, including CD19 targeting with blinatumomab and tisagenlecleucel and CD22 targeting with inotuzumab ozogamicin. These agents are now under investigation by the Children's Oncology Group (COG) in clinical trials for newly diagnosed B-ALL, with integration into standard chemotherapy regimens based on clinically and biology-based risk stratification as well as disease response.

Prevention of hepatitis B virus reactivation in patients with hematological malignancies and resolved hepatitis B virus infection: a systematic review and meta-analysis

OBJECTIVE

Patients with resolved hepatitis B virus (HBV) infection are at risk of HBV reactivation during treatment for hematological malignancies. We conducted a systematic review and meta-analysis of the data on the efficacy of antiviral prophylaxis for the prevention of HBV reactivation in this group of patients.

METHODS

We conducted a systemic literature search of PubMed including MEDLINE and EMBASE databases to 31 January 2019 to identify studies published in English comparing antiviral prophylaxis with no prophylaxis for HBV reactivation in patients treated for hematological malignancies. The search terms used were ("occult hepatitis B" OR "resolved hepatitis B") AND ("reactivation") AND ("haematological malignancy" OR "hematological malignancy" OR "chemotherapy" OR "immunotherapy" OR "chemoimmunotherapy" OR "lymphoma" OR "leukemia" OR "transplant"). The primary outcome was the reactivation of HBV infection. Pooled estimates of relative risk (RR) were calculated.

RESULTS

We identified 13 relevant studies including two randomized controlled trials (RCT), one post hoc analysis from RCT and 10 cohort studies. There was a trend towards a lower rate of HBV reactivation using antiviral prophylaxis, but the difference was not significant (RR 0.57, 95% confidence interval [CI] 0.23-1.40, P = 0.22). When limiting the analysis to the three prospective studies of patients receiving anti-CD20 monoclonal antibodies, we found antiviral prophylaxis was associated with a significantly lower risk of HBV reactivation (RR 0.17, 95% CI 0.06-0.49, P = 0.001).

CONCLUSION

Antiviral prophylaxis reduced the risk of HBV reactivation in patients receiving anti-CD20 monoclonal antibodies for hematological malignancies but not in a broader group of patients receiving anticancer therapy.