High-sensitivity next-generation sequencing MRD assessment in ALL identifies patients at very low risk of relapse

Advances in the treatment of Philadelphia chromosome negative acute lymphoblastic leukemia

There have been major paradigm shifts in the treatment of Philadelphia chromosome negative (Ph-) acute lymphoblastic leukemia (ALL) in the last decade with the introduction of new immunotherapies and targeted agents, adoption of pediatric-type chemotherapy protocols in younger adults as well as chemotherapy light approaches in older adults and the incorporation of measurable residual disease (MRD) testing to inform clinical decision making. With this, treatment outcomes in adult Ph- ALL have improved across all age groups. However, a subset of patients will still develop relapsed disease, which can be challenging to treat and associated with poor outcomes. Here we review the treatment of Ph- ALL in both younger and older adults, including the latest advancements and future directions.

SOHO State of the Art Updates and Next Questions, Measurable Residual Disease in Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia

Assessment of measurable residual disease (MRD) provides important prognostic information and can inform decision-making about appropriate consolidative therapy in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL). Many contemporary treatment protocols for Ph+ ALL achieve high rates of MRD negativity, and several analyses suggest that allogeneic hematopoietic stem cell transplant in first remission can be safely deferred in most patients who achieve MRD negativity by PCR for BCR::ABL1 within 3 months. Given the close association between achievement of MRD negativity and favorable long-term outcomes in Ph+ ALL, MRD response rates may aid in the evaluation of novel regimens, particularly in the absence of randomized data or robust survival data. While most studies in Ph+ ALL have used PCR for BCR::ABL1 to measure MRD and correlate with outcomes, this assay has several limitations. PCR or next-generation sequencing-based assays for immunoglobin or T-cell receptor (IG/TR) gene rearrangements may provide a more accurate assessment of clinically significant MRD in Ph+ ALL, particularly in patients with multilineage involvement of BCR::ABL1. Herein, we discuss the prognostic and therapeutic role of MRD in Ph+ ALL. We review the available methods of MRD assessment in Ph+ ALL and discuss the advantages of MRD assays that track IG/TR rearrangements rather than BCR::ABL1.

Comparison of Measurable Residual Disease in Pediatric B-Lymphoblastic Leukemia Using Multiparametric Flow Cytometry and Next-Generation Sequencing

Measurable residual disease (MRD) testing, a standard procedure in B-lymphoblastic leukemia (B-ALL) diagnostics, is assessed using multiparametric flow cytometry (MFC) and next-generation sequencing (NGS) analysis of immunoglobulin gene rearrangements. We evaluated the concordance between eight-color, two-tube MFC-MRD the LymphoTrack NGS-MRD assays using 139 follow-up samples from 54 pediatric patients with B-ALL. We also assessed the effect of hemodilution in MFC-MRD assays. The MRD-concordance rate was 79.9% (N=111), with 25 (18.0%) and 3 (2.2%) samples testing positive only by NGS-MRD (MFC-NGS+MRD) and MFC-MRD (MFC+NGS-MRD), respectively. We found a significant correlation in MRD values from total nucleated cells between the two methods (r=0.736 [0.647-0.806], P<0.001). The median MRD value of MFC-NGS+MRD samples was estimated to be 0.0012% (0.0001%-0.0263%) using the NGS-MRD assays. Notably, 14.3% of MFC-NGS+MRD samples showed NGS-MRD values below the limit of detection in the MFC-MRD assays. The percentages of hematogones detected in MFC-MRD assays significantly differed between the discordant and concordant cases (P<0.001). MFC and NGS-MRD assays showed relatively high concordance and correlation in MRD assessment, whereas the NGS-MRD assay detected MRD more frequently than the MFC-MRD assay in pediatric B-ALL. Evaluating the hematogone percentages can aid in assessing the impact of sample hemodilution.

Acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia (ALL) is a haematological malignancy characterized by the uncontrolled proliferation of immature lymphoid cells. Over past decades, significant progress has been made in understanding the biology of ALL, resulting in remarkable improvements in its diagnosis, treatment and monitoring. Since the advent of chemotherapy, ALL has been the platform to test for innovative approaches applicable to cancer in general. For example, the advent of omics medicine has led to a deeper understanding of the molecular and genetic features that underpin ALL. Innovations in genomic profiling techniques have identified specific genetic alterations and mutations that drive ALL, inspiring new therapies. Targeted agents, such as tyrosine kinase inhibitors and immunotherapies, have shown promising results in subgroups of patients while minimizing adverse effects. Furthermore, the development of chimeric antigen receptor T cell therapy represents a breakthrough in ALL treatment, resulting in remarkable responses and potential long-term remissions. Advances are not limited to treatment modalities alone. Measurable residual disease monitoring and ex vivo drug response profiling screening have provided earlier detection of disease relapse and identification of exceptional responders, enabling clinicians to adjust treatment strategies for individual patients. Decades of supportive and prophylactic care have improved the management of treatment-related complications, enhancing the quality of life for patients with ALL.

Advances in the treatment of adults with newly diagnosed B-cell acute lymphoblastic leukemia: the role of frontline immunotherapy-based regimens

Blinatumomab and inotuzumab ozogamicin (INO) are both active in relapsed/refractory B-cell acute lymphoblastic leukemia (ALL) and improve outcomes compared with conventional chemotherapy in this setting. Several prospective clinical trials have explored the use of these agents in adults with newly diagnosed B-cell ALL, with promising outcomes observed in younger and older adults and in both Philadelphia chromosome (Ph)-positive and Ph-negative ALL. These novel regimens result in high rates of deep measurable residual disease (MRD) negativity and may improve survival compared with chemotherapy-only approaches, allowing for less reliance on intensive chemotherapy and allogeneic hematopoietic stem cell transplantation (HSCT). This review discusses novel approaches to integrating INO and/or blinatumomab into frontline ALL regimens, including the potential role of chemotherapy-free regimens in some subgroups. The role of MRD monitoring is also discussed, including how this can inform decisions for consolidative allogeneic HSCT or investigational approaches with CD19 CAR T-cells.

SOHO State of the Art Updates and Next Questions | Next Questions: Acute Lymphoblastic Leukemia

The integration of immune and targeted therapies into the treatment of acute lymphoblastic leukemia (ALL) has significantly improved outcomes, reduced the intensity and duration of chemotherapy, and the reliance on allogeneic stem cell transplantation (SCT). In younger patients with Philadelphia chromosome (Ph)-negative ALL, treatment with Hyper-CVAD and blinatumomab +/- inotuzumab has improved the 3-year overall survival (OS) to above 85%. In older patients, using less intensive chemotherapy (mini-Hyper-CVD) in combination with inotuzumab and blinatumomab has improved the 5-year OS rate to 50%. In Ph+ ALL, the chemotherapy-free combinations of blinatumomab and ponatinib (or dasatinib) have become a new standard of care resulting in 3-year OS of 85% to 90%. Because the methotrexate-cytarabine courses were omitted in the nonchemotherapy regimens, central nervous system (CNS) relapses were noted, particularly in patients with a WBC count > 70 × 109/L, requiring to consider increasing the number of prophylactic intrathecals (from 12 to 15) and perhaps developing a CNS risk-directed high-dose systemic chemotherapy. In relapsed/refractory ALL, a dose-dense regimen integrating blinatumomab and inotuzumab with low-intensity chemotherapy followed by consolidation with chimeric antigen receptor T-cell therapy is being investigated. The detection of measurable residual disease (MRD) following ALL therapy is predictive of disease relapse. Using next-generation sequencing allows the detection of MRD at 1 × 10-6 which was shown to be superior to multiparameter flow cytometry and polymerase chain reaction in predicting relapse, and could be used to decide on the duration of therapy or need to change therapy. Herein, we review the recent updates and areas of unmet need in ALL.

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.

SOHO State of the Art Updates and Next Questions: Update on the Approach to Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia

The outcome of Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL) has improved significantly following the introduction of the BCR::ABL1 tyrosine kinase inhibitors (TKIs). The addition of newer-generation and more potent TKIs resulted in higher rates of molecular responses and better survival. Achieving a complete molecular remission (CMR; disappearance of the BCR::ABL1 transcripts) within the first 3 months of therapy is an important endpoint in newly diagnosed Ph-positive ALL that identifies patients who have an excellent long-term survival and who may not need to receive an allogeneic hematopoietic stem cell transplantation (HSCT) in first complete remission (CR). Chemotherapy-free combinations with blinatumomab plus TKIs showed encouraging results with estimated 2 to 4 year overall survival (OS) rates of 80% to 90%. Treatment with blinatumomab and ponatinib resulted in a CMR rate of 84%, a 2-year event-free survival (EFS) of 78%, and a 2-year OS rate of 90%; only 1 patient underwent HSCT. The detection of measurable residual disease (MRD) is the most important factor predicting for disease relapse. Studies have shown that the next-generation sequencing (NGS) assay is more sensitive than RT-PCR for the detection of MRD in Ph-positive ALL. Approximately 15% to 30% of patients who achieve NGS MRD negativity at a sensitivity of 1 × 10-6 may still have detectable BCR::ABL1 transcripts by RT-PCR. Achieving NGS MRD negativity can also identify patients who may have durable remissions with a low risk of relapse. Herein, we discuss the current approach to the management of adults with Ph-positive ALL, the role of HSCT, MRD monitoring, and future therapies.

Benefits and risks of clofarabine in adult acute lymphoblastic leukemia investigated in depth by multi-state modeling

BACKGROUND

We recently reported results of the prospective, open-label HOVON-100 trial in 334 adult patients with acute lymphoblastic leukemia (ALL) randomized to first-line treatment with or without clofarabine (CLO). No improvement of event-free survival (EFS) was observed, while a higher proportion of patients receiving CLO obtained minimal residual disease (MRD) negativity.

AIM

In order to investigate the effects of CLO in more depth, two multi-state models were developed to identify why CLO did not show a long-term survival benefit despite more MRD-negativity.

METHODS

The first model evaluated the effect of CLO on going off-protocol (not due to refractory disease/relapse, completion or death) as a proxy of severe treatment-related toxicity, while the second model evaluated the effect of CLO on obtaining MRD negativity. The subsequent impact of these intermediate events on death or relapsed/refractory disease was assessed in both models.

RESULTS

Overall, patients receiving CLO went off-protocol more frequently than control patients (35/168 [21%] vs. 18/166 [11%], p = 0.019; HR 2.00 [1.13-3.52], p = 0.02), especially during maintenance (13/44 [30%] vs. 6/56 [11%]; HR 2.85 [95%CI 1.08-7.50], p = 0.035). Going off-protocol was, however, not associated with more relapse or death. Patients in the CLO arm showed a trend towards an increased rate of MRD-negativity compared with control patients (HR MRD-negativity: 1.35 [0.95-1.91], p = 0.10), which did not translate into a significant survival benefit.

CONCLUSION

We conclude that the intermediate states, i.e., going off-protocol and MRD-negativity, were affected by adding CLO, but these transitions were not associated with subsequent survival estimates, suggesting relatively modest antileukemic activity in ALL.

A comprehensive case study on successful multimodal therapy in philadelphia chromosome-positive acute myeloid leukemia with NPM1 and IDH2 mutations

A 67-year-old female came to Tampa General Hospital with Philadelphia chromosome-positive (Ph+) acute myeloid leukemia (AML) featuring an intriguing combination of mutations, including NPM1 and IDH2 mutations. Novel combination therapy with azacitidine, venetoclax and ponatinib allowed her to successfully achieve a complete response (CR) and undergo an allogeneic hematopoietic stem cell transplant (HSCT). This case report provides an overview of her clinical course, emphasizing the significance of integrated therapy and the challenges associated with balancing treatment for AML. It also underscores the importance of a multidisciplinary approach and careful monitoring of patients with complex hematologic conditions.

Non-invasive prenatal test identifies circulating cell-free DNA chromosomal abnormalities derived from clonal hematopoiesis in aggressive hematological malignancies

Liquid biopsy is a minimally invasive diagnostic tool for identification of tumor-related mutations in circulating cell-free DNA (cfDNA). The aim of this study was to investigate feasibility, sensitivity, and specificity of non-invasive prenatal test (NIPT) for identification of chromosomal abnormalities in cfDNA from a total of 77 consecutive patients with non-Hodgkin B-cell lymphomas, Hodgkin lymphoma (HL), or plasma cell dyscrasia. In this case series, half of patients had at least one alteration, more frequently in chromosome 6 (23.1%), chromosome 9 (20.5%), and chromosomes 3 and 18 (16.7%), with losses of chromosome 6 and gains of chromosome 7 negatively impacting on overall survival (OS), with a 5-year OS of 26.9% and a median OS of 14.6 months, respectively (P = 0.0009 and P = 0.0004). Moreover, B-cell lymphomas had the highest NIPT positivity, especially those with aggressive lymphomas, while patients with plasma cell dyscrasia with extramedullary disease had a higher NIPT positivity compared to conventional cytogenetics analysis and a worse outcome. Therefore, we proposed a NIPT-based liquid biopsy a complementary minimally invasive tool for chromosomal abnormality detection in hematological malignancies. However, prospective studies on larger cohorts are needed to validate clinical utility of NIPT-based liquid biopsy in routinely clinical practice.

Dose-Dense Mini-Hyper-CVD, Inotuzumab Ozogamicin and Blinatumomab Achieves Rapid MRD-Negativity in Philadelphia Chromosome-Negative B-cell Acute Lymphoblastic Leukemia

BACKGROUND

The combination of low-intensity chemotherapy and inotuzumab ozogamicin (INO), with sequential blinatumomab, is highly effective in older adults with newly diagnosed B-cell acute lymphoblastic leukemia (ALL) and in relapsed or refractory B-cell ALL. Earlier, "dose-dense" administration of blinatumomab could lead to earlier and deeper measurable residual disease (MRD) responses and better outcomes.

PATIENTS AND METHODS

We performed a retrospective analysis of the safety and efficacy of a dose-dense regimen of mini-hyper-CVD (mini-hyperfractionated cyclophosphamide, vincristine, and dexamethasone alternating with mini-methotrexate and cytarabine), INO, and blinatumomab in patients with B-cell ALL.

RESULTS

Twenty-one patients were treated (frontline, n = 9; MRD consolidation, n = 4; relapsed/refractory, n = 8). In the frontline cohort, all patients achieved CR/CRi and MRD negativity by flow cytometry at the end of cycle 1. Across the frontline and MRD consolidation cohorts, 10/11 patients (91%) achieved next-generation sequencing MRD negativity at a sensitivity of 10-6, including 6/10 evaluable patients (60%) who achieved next-generation sequencing MRD negativity after cycle 1. The CR/CRi rate in the relapsed/refractory cohort was 63%, and all responders achieved MRD negativity by flow cytometry at the end of cycle 1. The 1-year overall survival rate for the combined cohort of the frontline and MRD-positive patients was 83%. No new safety signals were observed with the dose-dense mini-hyper-CVD, INO, and blinatumomab regimen.

CONCLUSION

Dose-dense delivery of mini-hyper-CVD, INO, and blinatumomab was safe and resulted in rapid and deep MRD negativity in patients with B-cell ALL. This regimen is now being prospectively evaluated in both the frontline and relapsed/refractory settings.

Concordance of Next-Generation Sequencing and Multiparametric Flow Cytometry Methods for Detecting Measurable Residual Disease in Adult Acute Lymphoblastic Leukemia: Optimizing Prediction of Clinical Outcomes From a Single-Center Study

INTRODUCTION

Detection of measurable residual disease (MRD) in adults with acute lymphoblastic leukemia (ALL) is a vital biomarker in risk prediction and treatment selection. Next-generation sequencing (NGS) offers greater sensitivity relative to multiparametric flow cytometry (MFC) and may be a better predictive tool for identifying ALL patients at risk of relapse.

PATIENTS AND METHODS

This single-center retrospective study compares MRD detection by NGS versus MFC in 52 adult B- and T-ALL patients treated at our institution between 2018 and 2023. Pretreatment bone marrow samples were used for assay calibration, while post-treatment MRD assessment was completed up to 4.5 months after the first complete remission (CR1) using an MRD cutoff of 10-6 for distinguishing relapse risk.

RESULTS

The 2-year cumulative incidence of relapse (CIR) among patients who were MRD positive using MFC and NGS was 39.5% and 46.2%, respectively. Unlike MFC, post-CR1 MRD positivity with NGS significantly predicted CIR (HR = 9.47, P = .028). In patients who were MRD negative by MFC, low levels of MRD detected by NGS distinguished patients at high risk of relapse (HR 10.3, P = .026, 2-year CIR 51.6%).

CONCLUSION

Our data suggests that assessment of post-CR1 MRD using a highly sensitive NGS assay can identify ALL patients undergoing frontline therapy at increased risk of relapse and guide the use of adjuvant therapy.

Quantification of Measurable Residual Disease Detection by Next-Generation Sequencing-Based Clonality Testing in B-Cell and Plasma Cell Neoplasms

Next-generation sequencing (NGS)-based measurable residual disease (MRD) monitoring in post-treatment settings can be crucial for relapse risk stratification in patients with B-cell and plasma cell neoplasms. Prior studies have focused on validation of various technical aspects of the MRD assays, but more studies are warranted to establish the performance characteristics and enable standardization and broad utilization in routine clinical practice. Here, the authors describe an NGS-based IGH MRD quantification assay, incorporating a spike-in calibrator for monitoring B-cell and plasma cell neoplasms based on their unique IGH rearrangement status. Comparison of MRD status (positive or undetectable) by NGS and flow cytometry (FC) assays showed high concordance (91%, 471/519 cases) and overall good linear correlation in MRD quantitation, particularly for chronic lymphocytic leukemia and B-lymphoblastic leukemia/lymphoma (R = 0.85). Quantitative correlation was lower for plasma cell neoplasms, where underestimation by FC is a known limitation. No significant effects on sequencing efficiency by the spike-in calibrator were observed, with excellent inter- and intra-assay reproducibility within the authors' laboratory, and in comparison to an external laboratory, using the same assay and protocols. Assays performed both at internal and external laboratories showed highly concordant MRD detection (100%) and quantitation (R = 0.97). Overall, this NGS-based MRD assay showed highly reproducible results with quantitation that correlated well with FC MRD assessment, particularly for B-cell neoplasms.

Leveraging health care technology to improve health outcomes and reduce outcome disparities in AYA leukemia

Significant improvements have occurred for adolescent and young adult (AYA) B-cell acute lymphoblastic leukemia (B-ALL) patients following the widespread adoption of "pediatric-inspired" treatment regimens for AYA patients cared for in adult oncology settings. However, for AYA patients, aged 15 to 39, an outcomes gap remains in B-ALL, necessitating the incorporation of novel therapies into up-front treatment regimens. As a result, clinical trial enrollment remains the current standard of care for AYA B-ALL across disease subtypes when available and accessible. Currently, several up-front trials are looking to incorporate the use of inotuzumab, blinatumomab, and chimeric antigen receptor T-cell therapy into existing chemotherapy backbones for AYA patients, as well as tyrosine kinase inhibitors for both Philadelphia-positive (Ph+) and Ph-like B-ALL. In addition to ongoing attempts to improve up-front treatments by incorporating immunotherapy and targeted approaches, the increased use of next generation sequencing for measurable residual disease evaluation has led to superior risk-stratification and a decreased need to pursue consolidative hematopoietic stem cell transplantation during the first complete remission for many patients.

An Update on the Management of Advanced Phase Chronic Myeloid Leukemia

PURPOSE OF REVIEW

While most patients with chronic myeloid leukemia (CML) present in a chronic phase and are expected to have a normal life expectancy, some patients present with or progress to a more aggressive accelerated phase (AP) or blast phase (BP) of CML. Herein, we discuss the diagnostic considerations of advanced phase CML and review its contemporary management.

RECENT FINDINGS

Later-generation, more potent BCR::ABL1 tyrosine kinase inhibitors (TKIs) such as ponatinib may result in superior outcomes in patients with advanced phase CML. For CML-BP, combination approaches directed against the blast immunophenotype appear superior to TKI monotherapy. The role of allogeneic stem cell transplantation is controversial in CML-AP but has consistently been shown to improve outcomes for patients with CML-BP. Advanced phase CML, particularly CML-BP, remains a poor risk subtype of CML. However, novel combination approaches using later-generation TKIs are being explored in clinical trials and may lead to improved outcomes.

The effectiveness of blinatumomab in clearing measurable residual disease in pediatric B-cell acute lymphoblastic leukemia patients detected by next-generation sequencing

BACKGROUND

Blinatumomab improved survival outcomes in B-cell acute lymphoblastic leukemia (B-ALL) patients with measurable residual disease (MRD) <10-4 . However, data on blinatumomab clearing MRD with high sensitivity of 10-6 remain scarce. This study evaluates the effectiveness of blinatumomab in eradicating extremely low level (up to <10-6 ) of MRD, as detected by next-generation sequencing (NGS), in children with B-ALL.

METHODS

Patients (n = 19) whose MRD was undetectable by multiparameter flow cytometry (MFC) (sensitivity of 10-4 ) but detectable by NGS after chemotherapy and followed by blinatumomab consolidation were included retrospectively.

RESULTS

After one course of blinatumomab, 13/19 patients (68%) successfully achieved NGS-MRD clearance (undetectable). With a median follow-up of 13.3 months, three of patients who were NGS-MRD positive relapsed within 1.8 months, while another three remained complete remission.

CONCLUSIONS

Our study was the first to demonstrate that blinatumomab could further eradicate MRD after patients achieve MFC-MRD undetectable in B-ALL patients.

Minimal residual disease detection by next-generation sequencing of different immunoglobulin gene rearrangements in pediatric B-ALL

While the prognostic role of immunoglobulin heavy chain locus (IGH) rearrangement in minimal residual disease (MRD) in pediatric B-acute lymphoblastic leukemia (B-ALL) has been reported, the contribution of light chain loci (IGK/IGL) remains elusive. This study is to evaluate the prognosis of IGH and IGK/IGL rearrangement-based MRD detected by next-generation sequencing in B-ALL at the end of induction (EOI) and end of consolidation (EOC). IGK/IGL rearrangements identify 5.5% of patients without trackable IGH clones. Concordance rates for IGH and IGK/IGL are 79.9% (cutoff 0.01%) at EOI and 81.0% (cutoff 0.0001%) at EOC, respectively. Patients with NGS-MRD < 0.01% at EOI or <0.0001% at EOC present excellent outcome, with 3-year event-free survival rates higher than 95%. IGH-MRD is prognostic at EOI/EOC, while IGK-MRD at EOI/EOC and IGL-MRD at EOI are not. At EOI, NGS identifies 26.2% of higher risk patients whose MRD < 0.01% by flow cytometry. However, analyzing IGK/IGL along with IGH fails to identify additional higher risk patients both at EOI and at EOC. In conclusion, IGH is crucial for MRD monitoring while IGK and IGL have relatively limited value.

CSRP2 transcript levels after consolidation therapy increase prognostic prediction ability in B-cell acute lymphoblastic leukaemia

Quantification of measurable residual disease (MRD) correlates with the risk of leukemia recurrence in adults with B-cell acute lymphoblastic leukemia (ALL). However, it remains unknown whether collecting data on cysteine and glycine-rich protein 2 (CSRP2) transcript levels, after completing the second course of consolidation, improves prognosis prediction accuracy. A total of 204 subjects with B-cell ALL were tested for CSPR2 transcripts after completing the second course of consolidation using quantitative real-time polymerase chain reaction (qRT-PCR) and divided into high (N = 32) and low (N = 172) CSRP2 expression cohorts. In multivariable analyses, subjects with high expression of CSRP2 had a higher 5-year cumulative incidence of relapse (CIR) (hazard ratio [HR] = 2.57, 95% confidence interval [CI] 1.38-4.76; P = 0.003), lower 5-year relapse-free survival (RFS) (HR = 3.22, 95% CI 1.75-5.93; P < 0.001), and overall survival (OS) (HR = 4.59, 95% CI 2.64-7.99; P < 0.001) in the whole cohort, as well as in the multi-parameter flow cytometry (MPFC) MRD-negative cohort (for CIR, HR = 2.70, 95% CI 1.19-6.12; for RFS, HR = 4.37, 95% CI 1.94-9.85; for OS, HR = 4.90, 95% CI 2.43-9.90; all P < 0.05). Prognostic analysis showed that allogeneic hematopoietic stem cell transplantation (allo-HSCT) could significantly improve the prognosis of patients with high CSRP2 expression (allo-HSCT vs chemotherapy: 5-year CIR, 52% vs 91%; RFS, 41% vs 9%; OS, 38% vs 20%; all P < 0.05). Our data indicate that incorporating data from CSPR2 transcript levels to the MRD-testing at the end of the second course of consolidation therapy enhances prognosis prediction accuracy in adults with B-cell ALL.

Tisagenlecleucel utilisation and outcomes across refractory, first relapse and multiply relapsed B-cell acute lymphoblastic leukemia: a retrospective analysis of real-world patterns

Background

Tisagenlecleucel was approved by the Food and Drug Administration (FDA) in 2017 for refractory B-cell acute lymphoblastic leukemia (B-ALL) and B-ALL in ≥2nd relapse. Outcomes of patients receiving commercial tisagenlecleucel upon 1st relapse have yet to be established. We aimed to report real-world tisagenlecleucel utilisation patterns and outcomes across indications, specifically including patients treated in 1st relapse, an indication omitted from formal FDA approval.

Methods

We conducted a retrospective analysis of real-world tisagenlecleucel utilisation patterns across 185 children and young adults treated between August 30, 2017 and March 6, 2020 from centres participating in the Pediatric Real-World CAR Consortium (PRWCC), within the United States. We described definitions of refractory B-ALL used in the real-world setting and categorised patients by reported Chimeric Antigen Receptor (CAR) T-cell indication, including refractory, 1st relapse and ≥2nd relapse B-ALL. We analysed baseline patient characteristics and post-tisagenlecleucel outcomes across defined cohorts.

Findings

Thirty-six percent (n = 67) of our cohort received tisagenlecleucel following 1st relapse. Of 66 evaluable patients, 56 (85%, 95% CI 74-92%) achieved morphologic complete response. Overall-survival (OS) and event-free survival (EFS) at 1-year were 69%, (95% CI 58-82%) and 49%, (95% CI 37-64%), respectively, with survival outcomes statistically comparable to remaining patients (OS; p = 0.14, EFS; p = 0.39). Notably, toxicity was increased in this cohort, warranting further study. Interestingly, of 30 patients treated for upfront refractory disease, 23 (77%, 95% CI 58-90%) had flow cytometry and/or next-generation sequencing (NGS) minimum residual disease (MRD)-only disease at the end of induction, not meeting the historic morphologic definition of refractory.

Interpretation

Our findings suggested that tisagenlecleucel response and survival rates overlap across patients treated with upfront refractory B-ALL, B-ALL ≥2nd relapse and B-ALL in 1st relapse. We additionally highlighted that definitions of refractory B-ALL are evolving beyond morphologic measures of residual disease.

Funding

St. Baldrick's/Stand Up 2 Cancer, Parker Institute for Cancer Immunotherapy, Virginia and D.K. Ludwig Fund for Cancer Research.

SOHO State of the Art Updates and Next Questions | Philadelphia Chromosome Positive Acute Lymphoblastic Leukemia in Adults: Therapeutic Options and Challenges in 2023

The therapeutic landscape of Philadelphia chromosome positive acute lymphoblastic leukemia (ALL) for adults has dramatically changed over the past 2 decades; the emergence of newer generations of tyrosine kinase inhibitors and incorporation of targeted immunotherapies into front-line therapy have significantly improved outcomes to the point where an argument can be made that this entity may no longer be considered a high-risk ALL subgroup. In this review article, we discuss different front-line regimens (both intensive and deintensified regimens including chemotherapy-free regimens). We also review disease monitoring strategies, discuss the role of allogeneic hematopoietic stem cell transplantation, and discuss the rapidly changing therapeutic landscape for patients with relapsed disease.

Single-Step IGHV Next-Generation Sequencing Detects Clonality and Somatic Hypermutation in Lymphoid Malignancies: A Phase III Diagnostic Accuracy Study

BACKGROUND

Multiplex PCR based on consensus primers followed by capillary electrophoresis and Sanger sequencing are considered as the gold standard method for the evaluation of clonality and somatic hypermutation in lymphoid malignancies. As an alternative, the next-generation sequencing (NGS) of immune receptor genes has recently been proposed as a solution, due to being highly effective and sensitive. Here, we designed a phase III diagnostic accuracy study intended to compare the current gold standard methods versus the first commercially available NGS approaches for testing immunoglobulin heavy chain gene rearrangements.

METHODS

We assessed IGH rearrangements in 68 samples by means of both the NGS approach (LymphoTrack® IGH assay, and LymphoTrack® IGH somatic hypermutation assay, run on Illumina MiSeq) and capillary electrophoresis/Sanger sequencing to assess clonality and somatic hypermutations (SHM).

RESULTS

In comparison to the routine capillary-based analysis, the NGS clonality assay had an overall diagnostic accuracy of 96% (63/66 cases). Other studied criteria included sensitivity (95%), specificity (100%), positive predictive value (100%) and negative predictive value (75%). In discrepant cases, the NGS results were confirmed by a different set of primers that provided coverage of the IGH leader sequence. Furthermore, there was excellent agreement of the SHM determination with both the LymphoTrack® FR1 and leader assays when compared to the Sanger sequencing analysis (84%), with NGS able to assess the SHM rate even in cases where the conventional approach failed.

CONCLUSION

Overall, conventional Sanger sequencing and next-generation-sequencing-based clonality and somatic hypermutation analyses gave comparable results. For future use in a routine diagnostic workflow, NGS-based approaches should be evaluated prospectively and an analysis of cost-effectiveness should be performed.

Pediatric Hematopathology in the Era of Advanced Molecular Diagnostics: What We Know and How We Can Apply the Updated Classifications

Pediatric hematologic malignancies often show genetic features distinct from their adult counterparts, which reflect the differences in their pathogenesis. Advances in the molecular diagnostics including the widespread use of next-generation sequencing technology have revolutionized the diagnostic workup for hematologic disorders and led to the identification of new disease subgroups as well as prognostic information that impacts the clinical treatment. The increasing recognition of the importance of germline predisposition in various hematologic malignancies also shapes the disease models and management. Although germline predisposition variants can occur in patients with myelodysplastic syndrome/neoplasm (MDS) of all ages, the frequency is highest in the pediatric patient population. Therefore, evaluation for germline predisposition in the pediatric group can have significant clinical impact. This review discusses the recent advances in juvenile myelomonocytic leukemia, pediatric acute myeloid leukemia, B-lymphoblastic leukemia/lymphoma, and pediatric MDS. This review also includes a brief discussion of the updated classifications from the International Consensus Classification (ICC) and the 5th edition World Health Organization (WHO) classification regarding these disease entities.

Using Measurable Residual Disease to Optimize Management of AML, ALL, and Chronic Myeloid Leukemia

In this review, we discuss the use of measurable residual disease (MRD) in AML, ALL, and chronic myeloid leukemia (CML). Our aims were to review the different methodologies for MRD assessment; describe the clinical relevance and medical decision making on the basis of MRD; compare and contrast the usage of MRD across AML, ALL, and CML; and discuss what patients need to know about MRD as it relates to their disease status and treatment. Finally, we discuss ongoing challenges and future directions with the goal of optimizing MRD usage in leukemia management.

Ultrasensitive NGS MRD assessment in Ph+ ALL: Prognostic impact and correlation with RT-PCR for BCR::ABL1

Reverse transcription polymerase chain reaction (RT-PCR) for BCR::ABL1 is the most common and widely accepted method of measurable residual disease (MRD) assessment in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL); however, RT-PCR may not be an optimal measure of MRD in many cases of Ph+ ALL. We evaluated the clinical impact of a highly sensitive next-generation sequencing (NGS) MRD assay (sensitivity of 10^-6 ) and its correlation with RT-PCR for BCR::ABL1 in patients with Ph+ ALL. Overall, 32% of patients had a discordance between MRD assessment by RT-PCR and NGS, and 31% of patients who achieved NGS MRD negativity were PCR+ at the same timepoint. Among eight patients with long-term detectable BCR::ABL1 by PCR, six were PCR+/NGS-. These patients generally had stable PCR levels that persisted despite therapeutic interventions, and none subsequently relapsed; in contrast, patients who were PCR+/NGS+ had more variable PCR values that responded to therapeutic intervention. In a separate cohort of prospectively collected clinical samples, 11 of 65 patients (17%) with Ph+ ALL who achieved NGS MRD negativity had detectable BCR::ABL1 by PCR, and none of these patients relapsed. Relapse-free survival and overall survival were similar in patients who were PCR+/NGS- and PCR-/NGS-, suggesting that PCR for BCR::ABL1 did not provide additional prognostic information in patients who achieved NGS MRD negativity. NGS-based assessment of MRD is prognostic in Ph+ ALL and identifies patients with low-level detectable BCR::ABL1 who are unlikely to relapse nor to benefit from therapeutic interventions.

Phase II study of dose-adjusted EPOCH as initial therapy for adults with high-risk acute lymphoblastic leukemia

Treatments for adults with newly-diagnosed acute lymphoblastic leukemia (ALL) may be prohibitively toxic and/or resource-intense. To address this, we performed a phase II study of dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin (DA-EPOCH). Imatinib or dasatinib was added for Ph + disease; rituximab was added when CD20+. Fifty-three patients were evaluable: 28 with Ph + disease, and 25 with Ph-. All patients had ≥1 high-risk clinical feature. Measurable residual disease-negativity by multiparameter flow cytometry within 4 cycles was achieved in 71% in patients with Ph + ALL and 64% in Ph - ALL. Median overall survival (OS) was 49 months, with a 2-year OS of 71%. Median relapse-free survival (RFS) in the 47 patients that attained morphologic remission was 24 months, with a 2-year RFS of 57%. Early mortality was 2%. In summary, DA-EPOCH yields deep and durable remissions in adults with ALL comparable to some resource-intense strategies but with a low rate of treatment-related death.

[Optimized treatment of childhood B-lineage acute lymphoblastic leukemia]

Childhood acute lymphoblastic leukemia (ALL) accounts for about 75% of childhood leukemia cases, and B-lineage acute lymphoblastic leukemia (B-ALL) accounts for more than 80% of childhood ALL cases. Over the past half century, new molecular biological targets discovered by new techniques have been used in precise stratification of disease prognosis, and there has been a gradual increase in the 5-year overall survival rate of childhood ALL. With the increasing attention to long-term quality of life, the treatment of childhood B-ALL has been constantly optimized from induction therapy to the intensity of maintenance therapy, including the treatment of extramedullary leukemia without radiotherapy, which has been tried with successful results. The realization of optimized treatment also benefits from the development of new techniques associated with immunology and molecular biology and the establishment of standardized clinical cohorts and corresponding biobanks. This article summarizes the relevant research on the implementation of precise stratification and the intensity reduction and optimization treatment of B-ALL in recent years, providing reference for clinicians.

Challenges of detecting measurable/minimal disease in acute leukemia

Measurable/minimal residual disease (MRD) tracking has emerged as a powerful tool for assessing treatment response and predicting outcomes in acute leukemia. However, the clinical and technological challenges associated with MRD tracking must be addressed to improve its utility in routine patient care. This review article aims to provide a summary of the different MRD methodologies used in acute leukemia. It highlights the strengths, diagnostic pitfalls, and clinical utility associated with MRD tracking in this rapidly evolving field.

SOHO State of the Art Updates and Next Questions | Hyper-CVAD in 2022: Lessons Learned and New Approaches

Combination chemotherapy is the mainstay of treatment for acute lymphoblastic leukemia (ALL). The Hyper-CVAD regimen was developed in 1992 at MD Anderson Cancer Center and has since become a standard of care option for adult patients with ALL. Since its conception, a number of modifications have been implemented to customize the regimen for different patient populations and safely incorporate novel therapies without compromising tolerability. We aim to review the evolution of the Hyper-CVAD regimen over the past 3 decades, focusing on clinical pearls, as well as future directions.

Using immunotherapy and novel trial designs to optimise front-line therapy in adult acute lymphoblastic leukaemia: breaking with the traditions of the past

Multidrug chemotherapy has historically been the cornerstone of therapy for both children and adults with acute lymphocytic leukaemia. However, in the past decade, several novel immunotherapies have proven to be highly effective in the treatment of acute lymphocytic leukaemia, including the anti-CD22 antibody-drug conjugate inotuzumab ozogamicin, the CD3 × CD19 bispecific antibody blinatumomab, and two CD19-directed chimeric antigen receptor T-cell products. These agents are all approved in the USA as monotherapy for relapsed or refractory B-cell acute lymphocytic leukaemia. However, their use as single agents in the salvage setting might not be taking full advantage of their anti-leukaemia potential, because our ability to cure a patient is likely to be greatest when the most effective therapies are safety integrated into front-line treatment regimens. Several ongoing studies have yielded encouraging data with routine incorporation of inotuzumab ozogamicin or blinatumomab, or both, in patients with newly diagnosed acute lymphocytic leukaemia, and these approaches are emerging as new standards of care. In Philadelphia chromosome-positive acute lymphocytic leukaemia, chemotherapy-free regimens combining blinatumomab and a BCR-ABL1 tyrosine kinase inhibitor are changing acute lymphocytic leukaemia therapy, highlighting the potential for these novel agents to reduce-or perhaps eliminate-the need for chemotherapy in some subtypes. In this Viewpoint, we review promising data from ongoing clinical trials of novel immunotherapy-based combinations that are being explored in patients with newly diagnosed acute lymphocytic leukaemia. We also discuss the challenges of randomised studies in the rapidly evolving therapeutic landscape and argue for the ability of well designed, non-randomised studies to more rapidly advance the standard of care in acute lymphocytic leukaemia.

Frontline combination of ponatinib and hyper-CVAD in Philadelphia chromosome-positive acute lymphoblastic leukemia: 80-months follow-up results

The combination of ponatinib, a third-generation BCR::ABL1 tyrosine kinase inhibitor, with hyper-CVAD chemotherapy resulted in high rates of complete molecular remissions and survival, without the need for stem cell transplantation (SCT) in most patients with Philadelphia chromosome(Ph)-positive acute lymphocytic leukemia (ALL). Confirming these results in a large cohort of patients with longer follow-up would establish this regimen as a new standard of care. Adults with newly diagnosed Ph-positive ALL were treated with the hyper-CVAD regimen. Ponatinib was added as 45 mg daily × 14 during induction, then 45 mg daily continuously (first 37 patients) or 30 mg daily continuously, with dose reduction to 15 mg daily upon achievement of a complete molecular response (CMR; absence of a detectable BCR::ABL1 transcript by quantitative reverse transcription polymerase-chain reaction at a sensitivity of 0.01%). Maintenance therapy consisted of daily ponatinib and vincristine-prednisone monthly for 2 years, followed by daily ponatinib indefinitely. Twelve intrathecal injections of cytarabine alternating with methotrexate were given as central nervous system prophylaxis. The trial is registered on clinicaltrials.gov with the identifier NCT01424982. Eighty-six patients were treated. Their median age was 46 years (range, 21-80). All 68 patients with active disease at the initiation of therapy achieved complete response (CR) The cumulative CMR rate was 86%. Twenty- patients (23%) underwent allogeneic SCT. With a median follow-up of 80 months (range, 16-129 months), the estimated 6-year event-free survival rate was 65% and the overall survival rate was 75%. There was no difference in outcome by performance of allogeneic SCT in first CR. Common grade 3-5 adverse events included infection (n = 80, 93%), increased liver transaminases (n = 26, 31%) and total bilirubin (n = 13, 15%), hypertension (n = 15, 17%), pancreatitis (n = 13, 15%), hemorrhage (n = 12, 13%), and skin rash (n = 9, 10%). Two ponatinib-related deaths from myocardial infarction (3%; at months 2.6 and 4.3, respectively; both in CR) in the first 37 patients treated led to the ponatinib dose-modifications mentioned earlier, with no further ponatinib-related deaths observed. The long-term results of ponatinib and hyper-CVAD continue to demonstrate excellent outcome results and acceptable safety data, indicating that this strategy is another standard of care approach in frontline Ph-positive ALL.

Treatment de-escalation in Philadelphia chromosome-positive B-cell acute lymphoblastic leukemia: the emerging role of chemotherapy-free regimens

The management of Philadelphia chromosome-positive (Ph-positive) acute lymphoblastic leukemia (ALL) has witnessed major progress over the past two decades. Initially, the incorporation of the first-generation BCR::ABL1 tyrosine kinase inhibitor (TKI) imatinib into intensive chemotherapy regimens improved outcomes compared with chemotherapy alone. The combinations of chemotherapy with second- or third-generation TKIs further improved outcomes, with higher rates of complete molecular remission (CMR) and superior survival. The combination of ponatinib plus chemotherapy resulted in durable remissions and prolonged long-term survival, even in patients who did not receive allogeneic stem cell transplantation (SCT). The promising results seen with later-generation TKIs have caused many to re-evaluate the role of allogeneic SCT for patients who achieve CMR with potent TKI regimens. Recently, the chemotherapy-free combinations of blinatumomab plus TKIs were shown to be safe and effective in newly diagnosed Ph-positive ALL, sparing patients the toxicities associated with intensive chemotherapy. In particular, encouraging early results have been seen with the combination of blinatumomab plus ponatinib, suggesting that this regimen may represent a chemotherapy-free and SCT-sparing strategy for patients with Ph-positive ALL. Herein, we discuss the current evidence for frontline therapies of Ph-positive ALL, the treatment de-escalation strategies over time, and the role of allogeneic SCT in view of the emergence of newer chemotherapy-free regimens using potent TKIs.

Antigen Receptors Gene Analysis for Minimal Residual Disease Detection in Acute Lymphoblastic Leukemia: The Role of High Throughput Sequencing

The prognosis of adult acute lymphoblastic leukemia (ALL) is variable but more often dismal. Indeed, its clinical management is challenging, current therapies inducing complete remission in 65–90% of cases, but only 30–40% of patients being cured. The major determinant of treatment failure is relapse; consequently, measurement of residual leukemic blast (minimal residual disease, MRD) has become a powerful independent prognostic indicator in adults. Numerous evidences have also supported the clinical relevance of MRD assessment for risk class assignment and treatment selection. MRD can be virtually evaluated in all ALL patients using different technologies, such as polymerase chain reaction amplification of fusion transcripts and clonal rearrangements of antigen receptor genes, flow cytometric study of leukemic immunophenotypes and, the most recent, high throughput sequencing (HTS). In this review, the authors focused on the latest developments on MRD monitoring with emphasis on the use of HTS, as well as on the clinical impact of MRD monitoring.

Ponatinib and blinatumomab for Philadelphia chromosome-positive acute lymphoblastic leukaemia: a US, single-centre, single-arm, phase 2 trial

BACKGROUND

Ponatinib and blinatumomab are effective therapies in patients with Philadelphia chromosome-positive (Ph-positive) acute lymphoblastic leukaemia, and their combination might be a promising treatment option. In this study, we aimed to evaluate this chemotherapy-free strategy.

METHODS

We did a single-centre, single-arm, phase 2 study at the University of Texas MD Anderson Cancer Center, Houston, TX, USA, in patients aged 18 years or older with newly diagnosed or relapsed or refractory Ph-positive acute lymphoblastic leukaemia or chronic myeloid leukaemia in lymphoid blast phase. Patients with an ECOG performance status of 2 or less who had a total bilirubin concentration two-times the upper limit of normal (ULN) or less (≤2·4 mg/dL), alanine aminotransferase and aspartate aminotransferase concentration no more than three-times the ULN, and serum lipase and amylase concentrations no more than three-times the ULN were eligible for inclusion. Ponatinib 30 mg orally and continuous intravenous blinatumomab 28 μg over 24 h (for 28 days each cycle) were given in combination for up to five 42-day cycles, followed by ponatinib monotherapy. Patients received 12 doses of intrathecal chemotherapy as CNS prophylaxis. The primary endpoints were complete molecular response (defined as absence of a detectable BCR-ABL1 transcript by PCR at a sensitivity of 0·01%) in patients with newly diagnosed disease and overall response in patients with relapsed or refractory disease or chronic myeloid leukaemia in lymphoid blast phase. All assessments were done according to the intention-to-treat principle. The trial completed its original target accrual and was amended on March 23, 2022, to enrol an additional 30 patients, thus increasing the sample size to 90 patients. The trial is registered with ClinicalTrials.gov, NCT03263572, and it is ongoing.

FINDINGS

Between Feb 6, 2018, to May 6, 2022, 60 (83%) of 72 patients assessed were enrolled and received ponatinib and blinatumomab (40 [67%] patients had newly diagnosed Ph-positive acute lymphoblastic leukaemia, 14 [23%] had relapsed or refractory Ph-positive acute lymphoblastic leukaemia, and six [10%] had chronic myeloid leukaemia in lymphoid blast phase). 32 (53%) patients were men and 28 (47%) were women; 51 (85%) patients were White or Hispanic; and the median age of participants was 51 years (IQR 36-68). The median duration of follow-up for the entire cohort was 16 months (IQR 11-24). Of patients with newly diagnosed Ph-positive acute lymphoblastic leukaemia, 33 (87%) of 38 evaluable patients had a complete molecular response. 12 (92%) of 13 evaluable patients with relapsed or refractory Ph-positive acute lymphoblastic leukaemia had an overall response. 11 (79%) had a complete molecular response. Five (83%) of six patients with chronic myeloid leukaemia in lymphoid blast phase had an overall response. Two (33%) had a complete molecular response. The most common grade 3-4 adverse events that occurred in more than 5% of patients were infection (22 [37%] patients), increased amylase or lipase concentration (five [8%] patients), increased alanine aminotransferase or aspartate aminotransferase concentration (four [7%] patients), pain (four [7%] patients), and hypertension (four [7%] patients). One (2%) patient discontinued blinatumomab due to tremor. Three (5%) patients discontinued ponatinib secondary to cerebrovascular ischaemia, portal vein thrombosis, and coronary artery stenosis in one patient each. No treatment-related deaths were observed.

INTERPRETATION

The chemotherapy-free combination of ponatinib and blinatumomab resulted in high rates of complete molecular response in patients with newly diagnosed and relapsed or refractory Ph-positive acute lymphoblastic leukaemia. Patients with newly diagnosed Ph-positive acute lymphoblastic leukaemia could be spared the toxicities associated with chemotherapy and the need for allogeneic haematopoietic stem-cell transplantation in first response.

FUNDING

Takeda Oncology and Amgen.

SOHO State of the Art Updates and Next Questions: Measurable Residual Disease in Acute Lymphoblastic Leukemia - Optimization and Innovation in 2022 and Beyond

Measurable residual disease (MRD) is an established component of acute lymphoblastic leukemia (ALL) management in both children and adults. Society guidelines and expert consensus documents include assessment of MRD as the standard of care following induction therapy, consolidation therapy, and at additional time points, depending on the treatment regimen administered. Further, the approval of blinatumomab for MRD+ B-ALL has advanced the concept of MRD response as a clinical endpoint in ALL. Although the utility of MRD in ALL has been well defined over the last decades, several questions remain. In this review we focus on areas of ongoing controversy and exploration in ALL MRD, including the following: (1) Does increasing the depth of MRD assessment add prognostic value? (2) Is there a role for ongoing MRD monitoring once patients achieve MRD response? (3) Can MRD assessment of the peripheral blood be substituted for bone marrow? (4) Should MRD assays be applied to the analysis of the central nervous system (CNS)? Ongoing studies should answer the majority of these questions in the coming years.