Imatinib combined with induction or consolidation chemotherapy in patients with de novo Philadelphia chromosome-positive acute lymphoblastic leukemia: results of the GRAAPH-2003 study

How I treat adult Ph+ ALL

ABSTRACT

The Philadelphia (Ph) chromosome is one of the few genetic aberrations in which a casualty has been proven and, as such, represents a success in the history of medicine. This is also evident in the setting of Ph+ acute lymphoblastic leukemia (ALL), the most frequent genetic subgroup in adult ALL, whose incidence increases with age and whose prognosis, before the advent of tyrosine kinase inhibitors (TKIs), was particularly poor. The outcome and management of patients with Ph+ ALL have greatly improved since the incorporation of first-, second-, and third-generation TKIs in the therapeutic backbone and is further changing with the more recent introduction of immunotherapy. This allows for long-term survival rates currently ranging between 75% and 80%. The clinical scenario of adult Ph+ ALL has thus changed profoundly, and new challenges are emerging. In this article, illustrative clinical cases are used to discuss the current role of systemic chemotherapy and allogeneic stem cell transplant, the difficulty in treating central nervous system relapses and, more in general, relapses in the current therapeutic era, and the possibility of stopping TKIs. Finally, the challenges related to an optimal management of these patients are discussed.

Impact of the Type of Tyrosine Kinase Inhibitor (imatinib or dasatinib) Used Before allo-HCT on Outcome of Patients with Philadelphia-Positive Acute Lymphoblastic Leukemia. A Study on Behalf of the Acute Leukemia Working Party of the EBMT

The use of tyrosine kinase inhibitors (TKIs) during induction and consolidation, followed by allogeneic hematopoietic cell transplantation (allo-HCT), is a standard of care for patients with Philadelphia (Ph)-positive acute lymphoblastic leukemia (ALL). The goal of this study was to compare results of allo-HCT according to the type of TKI used pre-transplant, either imatinib, dasatinib or both. This was a retrospective, registry-based analysis including adult patients with Ph-positive ALL treated with allo-HCT between years 2010-2022. The analysis included 606 patients pre-treated with imatinib, 163 with dasatinib and 94 with both imatinib and dasatinib. Allo-HCTs were performed in first complete remission from either unrelated (56%), matched sibling (36%) or haploidentical donors (8%). Relapse incidence at 2 years was 26% in the imatinib group and 21% in the dasatinib group and 19% in the imatinib + dasatinib group (P = .06) while non-relapse mortality was 19%, 15%, and 23%, respectively (P = .37). No significant differences were found for leukemia-free survival (55% vs. 63% vs. 58%, P = .11) and overall survival (72% vs. 76% vs. 65%, P = .32). The incidence of grade 2-4 acute graft-versus-host disease (GVHD) and chronic GVHD was comparable across study groups, while the incidence of grade 3-4 acute GVHD was significantly increased for patients pre-treated with dasatinib alone (20%) than in the imatinib group (10%) or imatinib + dasatinib group (13%) (P = .002). On multivariate analysis a chance of GVHD and relapse-free survival (GRFS) was significantly decreased while the risk of grade 3-4 acute GVHD was increased for the dasatinib compared to imatinib group (hazard ratio, HR = 1.27, P = .048 and HR = 2.26, P = .0009, respectively). This study provides no evidence for the advantage of one TKI over another in terms of LFS and OS. However, the use of dasatinib is associated with increased risk of severe acute GVHD and decreased GRFS.

HVEM in acute lymphocytic leukemia facilitates tumour immune escape by inhibiting CD8+ T cell function

PURPOSE

Leukaemia remains a major contributor to global mortality, representing a significant health risk for a substantial number of cancer patients. Despite notable advancements in the field, existing treatments frequently exhibit limited efficacy or recurrence. Here, we explored the potential of abolishing HVEM (herpes virus entry mediator, TNFRSF14) expression in tumours as an effective approach to treat acute lymphoblastic leukaemia (ALL) and prevent its recurrence.

METHODS

The clinical correlations between HVEM and leukaemia were revealed by public data analysis. HVEM knockout (KO) murine T cell lymphoblastic leukaemia cell line EL4 were generated using CRISPR-Cas9 technology, and syngeneic subcutaneous tumour models were established to investigate the in vivo function of HVEM. Immunohistochemistry (IHC), RNA-seq and flow cytometry were used to analyse the tumour immune microenvironment (TIME) and tumour draining lymph nodes (dLNs). Immune functions were investigated by depletion of immune subsets in vivo and T cell functional assays in vitro. The HVEM mutant EL4 cell lines were constructed to investigate the functional domain responsible for immune escape.

RESULTS

According to public databases, HVEM is highly expressed in patients with ALL and acute myeloid leukemia (AML) and is negatively correlated with patient prognosis. Genetic deletion of HVEM in EL4 cells markedly inhibited tumour progression and prolonged the survival of tumour-bearing mice. Our experiments proved that HVEM exerted its immunosuppressive effect by inhibiting antitumour function of CD8+ T cell through CRD1 domain both in vivo and in vitro. Additionally, we identified a combination therapy capable of completely eradicating ALL tumours, which induces immune memory toward tumour protection.

CONCLUSIONS

Our study reveals the potential mechanisms by which HVEM facilitates ALL progression, and highlights HVEM as a promising target for clinical applications in relapsed ALL therapy.

How I treat newly diagnosed acute lymphoblastic leukemia

Treatment algorithms differ for adult patients with Philadelphia-negative (Ph-) and Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL). For Ph- ALL intensive induction-consolidation chemotherapy using "pediatric-inspired" protocols is a standard of care. Allogeneic hematopoietic cell transplantation (allo-HCT) from either an HLA-matched sibling, unrelated or haploidentical donor should be considered for patients with high estimated risk of relapse. Inadequate response at the level of measurable residual disease (MRD) is the strongest adverse prognostic factor. Patients with B-ALL and detectable MRD should be treated with blinatumomab. In the future, the use of blinatumomab and/or inotuzumab ozogamycin in addition to first-line chemotherapy may become a new standard of care reducing the role of allo-HCT. For patients with Ph+ ALL, tyrosine kinase inhibitors (TKI) are the most important components of treatment protocols, while the intensity of chemotherapy may be reduced. Allo-HCT is recommended for all patients treated with imatinib along with low-intensity chemotherapy. Results of phase-II studies using front-line dasatinib or ponatinib in sequence or in combination with blinatumomab are very promising. Such a strategy may allow the avoidance of systemic chemotherapy. The future role of allo-HCT in this context appears uncertain.

Tyrosine kinase inhibitor resistance in de novo BCR::ABL1-positive BCP-ALL beyond kinase domain mutations

ABSTRACT

A better understanding of ABL1 kinase domain mutation-independent causes of tyrosine kinase inhibitor (TKI) resistance is needed for BCR::ABL1-positive B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Although TKIs have dramatically improved outcomes, a subset of patients still experiences relapsed or refractory disease. We aimed to identify potential biomarkers of intrinsic TKI resistance at diagnosis in samples from 32 pediatric and 19 adult patients with BCR::ABL1-positive BCP-ALL. Reduced ex vivo imatinib sensitivity was observed in cells derived from newly diagnosed patients who relapsed after combined TKI and chemotherapy treatment compared with cells derived from patients who remained in continuous complete remission. We observed that ex vivo imatinib resistance was inversely correlated with the amount of (phosphorylated) BCR::ABL1/ABL1 protein present in samples that were taken at diagnosis without prior TKI exposure. This suggests an intrinsic cause of TKI resistance that is independent of functional BCR::ABL1 signaling. Simultaneous deletions of IKZF1 and CDKN2A/B and/or PAX5 (IKZF1plus), as well as deletions of PAX5 alone, were related to ex vivo imatinib resistance. In addition, somatic lesions involving ZEB2, SETD2, SH2B3, and CRLF2 were associated with reduced ex vivo imatinib sensitivity. Our data suggest that the poor prognostic value of IKZF1(plus) deletions is linked to intrinsic mechanisms of TKI resistance other than ABL1 kinase domain mutations in newly diagnosed pediatric and adult BCR::ABL1-positive BCP-ALL.

Long-Term Results of the Dasatinib-Blinatumomab Protocol for Adult Philadelphia-Positive ALL

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned coprimary or secondary analyses are not yet available. Clinical trial updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.We report the long-term results of the frontline trial with dasatinib and blinatumomab in induction/consolidation (GIMEMA LAL2116, D-ALBA) for adult Philadelphia-positive ALL (Ph+ ALL), which enrolled 63 patients of all ages. At a median follow-up of 53 months, disease-free survival, overall survival, and event-free survival are 75.8%, 80.7%, and 74.6%, respectively. No events have occurred among early molecular responders. A significantly worse outcome was recorded for IKZF1plus patients. Twenty-nine patients-93.1% being in molecular response (ie, complete molecular response or positive nonquantifiable) after dasatinib/blinatumomab-never received chemotherapy/transplant and continued with a tyrosine kinase inhibitor only; 28 patients remain in long-term complete hematologic response (CHR). An allogeneic transplant was carried out in first CHR mainly in patients with persistent minimal residual disease; 83.3% of patients are in continuous CHR. The transplant-related mortality was 12.5% for patients transplanted in first CHR and 13.7% overall. Nine relapses and six deaths have occurred. ABL1 mutations were found in seven cases. The final analysis of the D-ALBA study shows that a chemotherapy-free induction/consolidation regimen on the basis of a targeted strategy (dasatinib) and immunotherapy (blinatumomab) is effective in inducing durable long-term hematologic and molecular responses in adult Ph+ ALL, paving the way for a new era in the management of these patients.

Reduced-dose chemotherapy followed by blinatumomab in induction therapy for newly diagnosed B-cell acute lymphoblastic leukemia

BACKGROUND

Blinatumomab early-line treatment in B-cell precursor acute lymphoblastic leukemia (B-ALL) might improve clinical outcomes.

METHODS

We conducted a retrospective real-world cohort analysis in 20 newly diagnosed B-ALL patients who received reduced-dose chemotherapy (idarubicin, vindesine, and dexamethasone) for 1-3 weeks, followed by blinatumomab for 1-4 weeks as an induction therapy.

RESULTS

At the end of the induction therapy, a complete remission rate of 100% was achieved; 17 (85%) patients were minimal residual disease (MRD) negative (<1 × 10-4 ). Adverse events (AEs) were reported in 12 (60%) patients-43.8% were grade 1-2 and 56.2% were grade 3-4. No incidence of neurotoxicity or grade ≥3 cytokine release syndrome was reported.

CONCLUSIONS

Blinatumomab demonstrated a significant improvement in clinical outcomes in patients with newly diagnosed B-ALL irrespective of their poor-risk factor status and the pretreatment blast burden.

Haematopoietic Stem Cell Transplant Trends in Pakistan: Activity Survey from Pakistan Bone Marrow Transplant Group

Pakistan is the fifth most populous country with a population of 225 million and has health expenditure accounting for only 2.8 percent of gross domestic product (GDP). Accordingly, there are a limited number of haematology-oncology and transplant centers in the country. The Pakistan Blood and Marrow Transplant (PBMT) group was established in 2020, and this report is the first activity survey from January 2021 to December 2022 focusing on the trends of matched-related donor, haploidentical, and autologous transplants in a developing country. A total of 12 transplant centers contributed data on the modified PBMT survey form retrospectively and 806 haematopoietic stem cell transplants (HSCTs) were carried out during the study duration. Allogeneic HSCT constituted 595 (73.8%) of all the transplants; this is in stark contrast to Western data, where autologous HSCT accounts for the majority of transplants. ß-thalassemia major and aplastic anemia were the commonest indications for allogeneic HSCT, in contrast to Western data, where acute leukemia is the leading transplant indication. Autologous transplants were more frequently performed for Hodgkin's lymphoma as compared to non-Hodgkin's lymphoma and multiple myeloma. The use of peripheral and bone marrow stem cells was comparable. A myeloablative conditioning regimen was routinely used in patients with acute leukemia. This report provides an insight of HSCT trends in Pakistan which are different from those of Western centers contributing to transplant data from South Asia.

Ponatinib vs. Imatinib as Frontline Treatment for Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia: A Matching Adjusted Indirect Comparison

INTRODUCTION

Efficacy of ponatinib-based treatment for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL) has not been compared to imatinib-based treatments in head-to-head clinical trials. We evaluated its efficacy versus imatinib-based regimens using a matching adjusted indirect comparison.

METHODS

Two ponatinib studies were used: the phase 2 MDACC study of ponatinib + hyper-CVAD (cyclophosphamide, vincristine, doxorubicin, and dexamethasone) in adult patients and the phase 2 GIMEMA LAL1811 study of ponatinib + steroids in patients > 60 years/unfit for intensive chemotherapy and stem cell transplant. Studies on imatinib as first-line treatment in adults with Ph + ALL were identified using a systematic literature search. Population adjustment was based on the prognostic factors and effect modifiers identified by clinical experts. Hazard ratios (HRs) were calculated for overall survival (OS) and odds ratios (ORs) for complete molecular response (CMR).

RESULTS

The systematic literature search identified two studies (GRAAPH-2005 and NCT00038610) reporting the efficacy of first-line imatinib + hyper-CVAD and one study reporting the efficacy of first-line imatinib monotherapy induction + imatinib-based consolidation (CSI57ADE10). Ponatinib + hyper-CVAD prolonged OS and gave a higher CMR rate than imatinib + hyper-CVAD. The adjusted HR [95% confidence interval (CI)] for OS was 0.35 (0.17-0.74) for MDACC vs. GRAAPH-2005 and 0.35 (0.18-0.70) for MDACC vs. NCT00038610; the adjusted OR (95% CI) for CMR was 12.11 (3.77-38.87) for MDACC vs. GRAAPH-2005 and 5.65 (2.02-15.76) for MDACC vs. NCT00038610. Ponatinib + steroids prolonged OS and gave a higher CMR rate than imatinib monotherapy induction + imatinib-containing consolidation. The adjusted HR (95% CI) for OS was 0.24 (0.09-0.64) and the adjusted OR (95% CI) for CMR was 6.20 (1.60-24.00) for GIMEMA LAL1811 vs. CSI57ADE10.

CONCLUSION

In adults with newly diagnosed Ph + ALL, first-line treatment with ponatinib was associated with better outcomes than first-line treatment with imatinib.

Establishment and Characterization of an Acute Lymphocytic Leukemia Cell Line Expressing CD13 and CD33 with a Complex Philadelphia Translocation

Objective To investigate the pathogenesis of Philadelphia (Ph)-positive acute lymphocytic leukemia (ALL), we established a lymphoblastoid cell line. Methods Bone marrow cells from a patient with Ph-positive ALL were enriched by Ficoll-Hypaque centrifugation and cultured in medium with fetal calf serum. Materials The mononuclear cells of bone marrow aspirate were obtained from an adult man with ALL after he experienced relapse following induction therapy including imatinib mesylate. Results The cell line termed TNA-M was established, carrying a three-way Ph translocation involving two chromosome 9s and one chromosome 22 as a sole karyotypic abnormality. Furthermore, the cells were positive for CD13 and CD33 in addition to CD19, CD22 and CD79a antigens. Conclusion This unique cell line is expected to be a valuable tool for understanding the pathogenesis of Ph-positive ALL.

Thiotepa, busulfan and fludarabine conditioning-regimen is a promising approach for older adult patients with acute lymphoblastic leukemia treated with allogeneic stem cell transplantation

For acute lymphoblastic leukemia (ALL) patients, total body irradiation (TBI)- based conditioning regimens are the first choice specially in young population. However, several studies have shown an equivalence in clinical outcomes with thiotepa-based conditioning regimen. We performed a retrospective study to evaluate the outcome of adult ALL patients who received allogeneic hematopoietic stem cell transplantation (allo-HCT) with a thiotepa-busulfan-fludarabine (TBF) myeloablative conditioning regimen with reduced toxicity. Fifty-five patients received a TBF regimen. The median age of the patients was 51 years (range, 17 to 72.4). Most patients had a diagnosis of B-ALL (93%) with 7% having T-ALL. Two - and 5-year overall survival was 73.2% and 64%, respectively. At 2 years, leukemia-free survival and GVHD-free, relapse-free survival were 59.5% and 57.6%, and at 5 years, 53.4% and 51.8%, respectively. The 5-year non-relapse mortality was 15%. The day 180 cumulative incidence (CI) of grade II-IV acute GVHD and grade III-IV acute GVHD were 38.2% and 5.5%, respectively. At 2 years, the CI of chronic GVHD and extensive chronic GVHD was 16.9% and 1.9%, respectively. Our study results do suggest that using TBF as the conditioning regimen in adult ALL patients is a promising option with acceptable toxicity.

Evidence-Based Minireview: What is the optimal tyrosine kinase inhibitor for adults with newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia?

The incorporation of BCR::ABL1 tyrosine kinase inhibitors (TKIs) to intensive chemotherapy significantly improved the outcomes of patients with Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL). This was first shown with the addition of the first-generation TKI imatinib, which allowed more patients to be bridged to an allogeneic stem cell transplant (SCT) and led to superior long-term outcomes compared with chemotherapy alone. The use of second-generation TKIs (eg, dasatinib and nilotinib) has led to further improvement in outcomes of patients with Ph- positive ALL, with a long-term survival of 40% to 60% in several studies. Ponatinib is a third-generation, more potent TKI that results in high rates of molecular response and promising long-term survival even when allogeneic SCT is not routinely performed. While randomized data to support the TKI selection in Ph-positive ALL are lacking, data from single-arm studies suggest deeper molecular responses and superior survival outcomes with each successive generation of TKI. More recently, chemotherapy-free regimens with blinatumomab and TKIs have shown excellent results in the frontline setting and may represent an emerging paradigm shift in the treatment of Ph-positive ALL.

Treatment of Adults With Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia-From Intensive Chemotherapy Combinations to Chemotherapy-Free Regimens: A Review

Importance

With the advent of potent BCR::ABL1 tyrosine kinase inhibitors (TKIs), Philadelphia chromosome-positive (Ph-positive) acute lymphoblastic leukemia (ALL) is now a relatively favorable-risk acute leukemia. In this review, we discuss the current evidence for frontline therapies of Ph-positive ALL, the major principles that guide therapy, and the progress with chemotherapy-free regimens.

Observations

Incorporating TKIs into the chemotherapy regimens of patients with newly diagnosed Ph-positive ALL has led to improved remission rates, higher probability of reaching allogeneic stem cell transplantation (SCT), and longer survival compared with chemotherapy alone. Early achievement of a complete molecular remission (CMR) is an important end point in Ph-positive ALL and identifies patients who have excellent long-term survival and may not need allogeneic SCT. Second-generation TKIs combined with intensive or low-intensity chemotherapy resulted in higher CMR rates compared with imatinib-based regimens. This translated into better outcomes, with less reliance on allogeneic SCT. To further improve the outcomes, the potent third-generation TKI ponatinib was added to chemotherapy. The combination of hyper-CVAD and ponatinib resulted in an overall CMR rate of 84% and a 5-year survival rate of 73% and 86% among patients who did and did not undergo allogeneic SCT, respectively, suggesting that allogeneic SCT may not be needed with this regimen. The recent chemotherapy-free combination of dasatinib and blinatumomab was safe and effective in patients with newly diagnosed Ph-positive ALL and resulted in an estimated 3-year OS rate of 80%; 50% of patients underwent allogeneic SCT. The chemotherapy-free regimen of ponatinib and blinatumomab resulted in a CMR rate of 86% and a 2-year survival rate of 93%, with no relapses or leukemia-related deaths, and with only 1 patient proceeding to allogeneic SCT.

Conclusions and Relevance

The promising results obtained with the chemotherapy-free regimens of blinatumomab plus TKIs question the role of allogeneic SCT in first remission. Patients with Ph-positive ALL who achieve early and deep molecular responses have excellent long-term outcomes and may not benefit from allogeneic SCT.

Treatment of Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia in Adults

Simple Summary

Outcome of patients with Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ ALL) dramatically improved during the past 20 years with the advent of tyrosine kinase inhibitors and monoclonal antibodies. Their great efficacy in young and fit patients led to question our reliance on chemotherapy and allogeneic hematopoietic stem cell transplantation. Moreover, these well-tolerated treatments can be safely administrated even in the elderly that represent the majority of Ph+ ALL patient. This review will focus on the recent changes of paradigm in the management of Ph+ ALL patients and the development of novel therapeutic strategies.

Abstract

Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ ALL) is the most common subtype of B-ALL in adults and its incidence increases with age. It is characterized by the presence of BCR-ABL oncoprotein that plays a central role in the leukemogenesis of Ph+ ALL. Ph+ ALL patients traditionally had dismal prognosis and long-term survivors were only observed among patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) in first complete remission (CR1). However, feasibility of allo-HSCT is limited in this elderly population. Fortunately, development of increasingly powerful tyrosine kinase inhibitors (TKIs) from the beginning of the 2000′s dramatically improved the prognosis of Ph+ ALL patients with complete response rates above 90%, deep molecular responses and prolonged survival, altogether with good tolerance. TKIs became the keystone of Ph+ ALL management and their great efficacy led to develop reduced-intensity chemotherapy backbones. Subsequent introduction of blinatumomab allowed going further with development of chemo free strategies. This review will focus on these amazing recent advances as well as novel therapeutic strategies in adult Ph+ ALL.

BCR/ABL1-Like Acute Lymphoblastic Leukemia: From Diagnostic Approaches to Molecularly Targeted Therapy

BACKGROUND

BCR/ABL1-like acute lymphoblastic leukemia is a newly recognized high-risk subtype of ALL, characterized by the presence of genetic alterations activating kinase and cytokine receptor signaling. This subtype is associated with inferior outcomes, compared to other B-cell precursor ALL.

SUMMARY

The recognition of BCR/ABL1-like ALL is challenging due to the complexity of underlying genetic alterations. Rearrangements of CRLF2 are the most frequent alteration in BCR/ABL1-like ALL and can be identified by flow cytometry. The identification of BCR/ABL1-like ALL can be achieved with stepwise algorithms or broad-based testing. The main goal of the diagnostic analysis is to detect the underlying genetic alterations, which are critical for the diagnosis and targeted therapy.

KEY MESSAGES

The aim of the manuscript is to review the available data on BCR/ABL1-like ALL characteristics, diagnostic algorithms, and novel, molecularly targeted therapeutic options.

Acute Lymphoblastic Leukemia, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Acute Lymphoblastic Leukemia (ALL) focus on the classification of ALL subtypes based on immunophenotype and cytogenetic/molecular markers; risk assessment and stratification for risk-adapted therapy; treatment strategies for Philadelphia chromosome (Ph)-positive and Ph-negative ALL for both adolescent and young adult and adult patients; and supportive care considerations. Given the complexity of ALL treatment regimens and the required supportive care measures, the NCCN ALL Panel recommends that patients be treated at a specialized cancer center with expertise in the management of ALL This portion of the Guidelines focuses on the management of Ph-positive and Ph-negative ALL in adolescents and young adults, and management in relapsed settings.

Acute Lymphoblastic Leukemia and Acute Lymphoblastic Lymphoma: Same Disease Spectrum but Two Distinct Diagnoses

PURPOSE OF REVIEW

Rare malignancies developing from lymphocyte precursor cells, lymphoblastic leukemia (LBL), and acute lymphoblastic lymphoma (ALL) have historically been viewed as different manifestations of the same disease process. This review examines data on their epidemiology, genetics, clinical presentation, and response to treatment while highlighting areas of similarity and divergence between these two clinical entities.

RECENT FINDINGS

Pediatric-type ALL chemotherapy regimens, compared to both lymphoma-type chemotherapy and adult-type ALL regimens, have led to improved outcomes for children, adolescents, and young adults with ALL. BCR-ABL-targeting tyrosine kinase inhibitors (TKIs) have improved outcomes in Philadelphia chromosome-positive (Ph +) ALL and in rare cases of Ph + LBL. Newer therapies including blinatumomab, inotuzumab, CAR-T therapy, and nelarabine have improved outcomes in selected cases of ALL and have an emerging role in the management of LBL. Better understanding of ALL and LBL biology allows for the development of therapies that target immunophenotypic or genetic features found in subsets of both diseases. Novel therapies are leading to improved outcomes in Ph + and relapsed and refractory disease.

Applicability of droplet digital polymerase chain reaction for minimal residual disease monitoring in Philadelphia-positive acute lymphoblastic leukaemia

In Ph+ acute lymphoblastic leukaemia (Ph+ ALL), minimal residual disease (MRD) is the most relevant prognostic factor. Currently, its evaluation is based on quantitative real‐time polymerase chain reaction (Q‐RT‐PCR). Digital droplet PCR (ddPCR) was successfully applied to several haematological malignancies. We analyzed 98 samples from 40 Ph+ ALL cases, the majority enrolled in the GIMEMA LAL2116 trial: 10 diagnostic samples and 88 follow‐up samples, mostly focusing on positive non‐quantifiable (PNQ) or negative samples by Q‐RT‐PCR to investigate the value of ddPCR for MRD monitoring. DdPCR BCR/ABL1 assay showed good sensitivity and accuracy to detect low levels of transcripts, with a high rate of reproducibility. The analysis of PNQ or negative cases by Q‐RT‐PCR revealed that ddPCR increased the proportion of quantifiable samples (p < 0.0001). Indeed, 29/54 PNQ samples (53.7%) proved positive and quantifiable by ddPCR, whereas 13 (24.1%) were confirmed as PNQ by ddPCR and 12 (22.2%) proved negative. Among 24 Q‐RT‐PCR‐negative samples, 13 (54.1%) were confirmed negative, four (16.7%) resulted PNQ and seven (29.2%) proved positive and quantifiable by ddPCR. Four of 5 patients, evaluated at different time points, who were negative by Q‐RT‐PCR and positive by ddPCR experienced a relapse. DdPCR appears useful for MRD monitoring in adult Ph+ ALL.

Emerging tyrosine kinase inhibitors for the treatment of adult acute lymphoblastic leukemia

Introduction: The broadening of targeted and immunotherapeutic strategies markedly impacted on the management of acute lymphoblastic leukemia (ALL). The advent of tyrosine kinase inhibitors (TKIs) changed the history of Philadelphia-chromosome positive (Ph+) ALL. Nowadays, almost all Ph+ ALL patients treated with TKIs achieve a complete hematologic response, and most become minimal residual disease negative. In Ph- ALL, genomic profiling studies have identified a subtype associated with a high relapse risk and a transcriptional profile similar to that of Ph+ ALL, the so-called Ph-like ALL. Given the high prevalence of kinase-activating lesions in this subset, there is compelling evidence from experimental models and clinical observations favoring TKI administration.Areas covered: We discuss the main findings exploring the efficacy of TKIs in ALL.Expert opinion: The use of more potent TKIs will further enhance the inhibitory activity on leukemia cells and increase the possibility of eradicating the disease at a molecular level. In the future, 'combined' approaches of different inhibitors may be considered to prevent/avoid resistance and/or mutations. A rapid identification of Ph-like ALL patients is needed to propose early TKI-based intervention. Several questions remain open, including the initial TKI choice in Ph+ ALL and whether Ph-like ALL patients might benefit from immunotherapy.

Targeted Therapy in Acute Lymphoblastic Leukaemia

The last decade has seen a significant leap in our understanding of the wide range of genetic lesions underpinning acute lymphoblastic leukaemia (ALL). Next generation sequencing has led to the identification of driver mutations with significant implications on prognosis and has defined entities such as BCR-ABL-like ALL, where targeted therapies such as tyrosine kinase inhibitors (TKIs) and JAK inhibitors may play a role in its treatment. In Philadelphia positive ALL, the introduction of TKIs into frontline treatment regimens has already transformed patient outcomes. In B-ALL, agents targeting surface receptors CD19, CD20 and CD22, including monoclonal antibodies, bispecific T cell engagers, antibody drug conjugates and chimeric antigen receptor (CAR) T cells, have shown significant activity but come with unique toxicities and have implications for how treatment is sequenced. Advances in T-ALL have lagged behind those seen in B-ALL. However, agents such as nelarabine, bortezomib and CAR T cell therapy targeting T cell antigens have been examined with promising results seen. As our understanding of disease biology in ALL grows, as does our ability to target pathways such as apoptosis, through BH3 mimetics, chemokines and epigenetic regulators. This review aims to highlight a range of available and emerging targeted therapeutics in ALL, to explore their mechanisms of action and to discuss the current evidence for their use.

A multicenter total therapy strategy for de novo adult Philadelphia chromosome positive acute lymphoblastic leukemia patients: final results of the GIMEMA LAL1509 protocol

The GIMEMA LAL1509 protocol, designed for adult (≥18-60 years) de novo Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia (ALL) patients, was based on dasatinib plus steroids induction - with central nervous system prophylaxis - followed by dasatinib alone in patients in complete molecular response or by chemotherapy and/or allogeneic transplant in patients not reaching complete molecular response. Sixty patients (median age 41.9 years) were enrolled: 33 were p190+, 18 p210+ and nine p190/p210+. At the end of induction (day +85), 58 patients (97%) achieved complete hematologic remission. No deaths in induction were recorded. Eleven patients (18.3%) obtained complete molecular response. Among the incomplete molecular responders (n=47), 22 underwent an allogeneic transplant. Seventeen hematologic relapses occurred (median 7 months; range, 3-40.1): 13 during consolidation and four post-transplant. ABL1 mutations (five T315I, three V299L, one E281K and one G254E) were found in ten of 13 relapsed cases. With a median follow-up of 57.4 months (range, 4.2-75.6), overall survival and disease-free survival were 56.3% and 47.2%. A better disease-free survival was observed in patients who obtained a molecular response at day +85 compared to cases who did not. The presence of additional copy number aberrations - IKZF1 plus CDKN2A/B and/or PAX5 deletions - was the most important unfavorable prognostic factor on overall and disease-free survival (P=0.005 and P=0.0008). This study shows that in adult Ph+ ALL long-term survivals can be achieved with a total-therapy strategy based on a chemotherapyfree induction and, in complete molecular responders, also without further systemic chemotherapy. Finally, the screening of additional copy number aberrations should be included in the diagnostic work-up (clinicatrial gov. Identifier: EudraCT 2010-019119-39).

The impact of tyrosine kinase inhibitors on allogeneic hematopoietic stem cell transplantation for adult patients with Philadelphia chromosome-positive acute lymphoblastic leukemia

In the tyrosine kinase inhibitor (TKI) era, allogeneic hematopoietic stem cell transplantation (allo-HSCT) is still the most potential approach for cure of adult patients with Philadelphia chromosome-positive acute lymphocytic leukemia (Ph⁺ ALL). TKI plus chemotherapy has strikingly increased response rates and depth of response, and facilitated allo-HSCT, which decreases relapse and improves survival eventually. Meanwhile, for those with older age or comorbidities at diagnosis, TKI in combination with reduced-intensity chemotherapy or chemotherapy-free strategy reduces treatment-related mortality, deferred intensive chemotherapy increases molecular responses and reduced-intensity conditioning (RIC) allo-HSCT improves survival finally. Of note, according to minimal residual disease (MRD) and BCR/ABL1 kinase domain mutation screening, prophylactic or preemptive maintenance therapy with a sensitive TKI decreases relapse further. Regarding transplantation-related mortality and impaired quality of life related to complications of allo-HSCT, autologous-HSCT (auto-HSCT) among those with early and persistent molecular remission and the most potent TKI ponatinib plus intensive chemotherapy has exhibited non-inferior survival to allo-HSCT. Even so, risk-adapted strategy isn't available now. Lastly, outcomes of relapse after allo-HSCT are dismal due to TKIs exposure, and new therapeutic interventions combined with TKIs shed light on this thorny problem.

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.

Retrospective study of Dana Farber Consortium Protocol in newly diagnosed Egyptian adolescents and young adults with acute lymphoblastic leukemia: Tanta experience

BACKGROUND

Intensive acute lymphoblastic leukemia (ALL) regimens in children improve the 5-year event-free survival (EFS) to reach ~ 90%. Adolescents and young adults (AYA) have EFS (30% to 45%). Young AYA ALL patients treated with pediatric chemotherapy protocols such as Dana Farber Consortium Protocol (DFCP) experience a better prognosis. This study aimed to assess the efficacy [EFS and overall survival (OS)] and the toxicity of DFCP in the treatment of Egyptian AYA with newly diagnosed ALL. A retrospective study was performed on 41 patients with newly diagnosed ALL (15 and 39 years) who were treated with DFCP. EFS and OS were estimated using the Kaplan-Meier method.

RESULTS

Thirty-eight patients (92.68%) achieved complete remission (CR). Eleven patients (26.83%) relapsed. Ten (24.39%) patients died. One, two, and three years of EFS were 75.61%, 72.91%, and 67.51% respectively. One, two, and three years OS were 85.3%, 77.26%, and 74.39% respectively. Neutropenia was the most common adverse event observed in 100% of patients.

CONCLUSION

DFCP can be considered as an effective ALL protocol for the AYA group of patients with good CR, EFS, and OS rates. DFCP seemed to be feasible in AYA despite the toxicities experienced.

Dasatinib-Blinatumomab for Ph-Positive Acute Lymphoblastic Leukemia in Adults

BACKGROUND

Outcomes in patients with Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL) have improved with the use of tyrosine kinase inhibitors. Molecular remission is a primary goal of treatment.

METHODS

We conducted a phase 2 single-group trial of first-line therapy in adults with newly diagnosed Ph-positive ALL (with no upper age limit). Dasatinib plus glucocorticoids were administered, followed by two cycles of blinatumomab. The primary end point was a sustained molecular response in the bone marrow after this treatment.

RESULTS

Of the 63 patients (median age, 54 years; range, 24 to 82) who were enrolled, a complete remission was observed in 98%. At the end of dasatinib induction therapy (day 85), 29% of the patients had a molecular response, and this percentage increased to 60% after two cycles of blinatumomab; the percentage of patients with a molecular response increased further after additional blinatumomab cycles. At a median follow-up of 18 months, overall survival was 95% and disease-free survival was 88%; disease-free survival was lower among patients who had an IKZF1 deletion plus additional genetic aberrations (CDKN2A or CDKN2B, PAX5, or both [i.e., IKZF1 ^plus]). ABL1 mutations were detected in 6 patients who had increased minimal residual disease during induction therapy, and all these mutations were cleared by blinatumomab. Six relapses occurred. Overall, 21 adverse events of grade 3 or higher were recorded. A total of 24 patients received a stem-cell allograft, and 1 death was related to transplantation (4%).

CONCLUSIONS

A chemotherapy-free induction and consolidation first-line treatment with dasatinib and blinatumomab that was based on a targeted and immunotherapeutic strategy was associated with high incidences of molecular response and survival and few toxic effects of grade 3 or higher in adults with Ph-positive ALL. (Funded by Associazione Italiana per la Ricerca sul Cancro and others; GIMEMA LAL2116 D-ALBA EudraCT number, 2016-001083-11; ClinicalTrials.gov number, NCT02744768.).

How we approach Philadelphia chromosome-positive acute lymphoblastic leukemia in children and young adults

Treatment for children with Philadelphia chromosome-positive acute lymphoblastic leukemia has changed radically over the past 20 years. This type of leukemia used to have dismal prognosis, but today cure rates have improved with combination of cytotoxic chemotherapy and a tyrosine kinase inhibitor such as imatinib or dasatinib, with hematopoietic stem cell transplant reserved for patients who are at high risk based on slow response to therapy or who relapse. Treating these patients can be challenging particularly if they are not enrolled on a clinical trial. Here, we describe our approach to these patients.

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.

The impacts of BCR-ABL1 mutations in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia who underwent allogeneic hematopoietic cell transplantation

The prognostic impacts of BCR-ABL1 fusion gene mutations in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL) remain unknown. Using data from a nationwide Japanese registry, we have evaluated the prognostic impact of BCR-ABL1 mutations prior to the first allogeneic hematopoietic cell transplantation (HCT). The cohort included 289 patients with a median of 48 years of age (range: 16-70). Point mutations were detected in 110 patients. Of these, 90 (82%) harbored T315I mutations, while 20 had other mutations. With a median follow-up period of 29 months (range: 1-125), outcomes after 2 years were worse with mutations than without (overall survival [OS]: 34% vs 68%, p < 0.001; relapse rate [RR]: 48% vs 18%, p < 0.001), particularly with the presence of the T315I mutation (OS: 29% vs 68%, p < 0.001; RR: 54% vs 18%, p < 0.001). OS was significantly worse in the T315I group even among the cohort with hematological (p < 0.001) or molecular complete remission (p = 0.025) as compared to the no mutation group. Multivariate analysis determined the prognostic impact of the T315I mutation (OS: hazard ratio [HR] = 2.19, 95% confidence interval [CI]: 1.5-3.3, p < 0.001; RR: HR = 2.51, 95% CI: 1.5-4.2, p < 0.001). This study is the first to report on the prognostic significance of BCR-ABL1 mutations in Ph + ALL.

Maintenance Strategies After Hematopoietic Cell Transplantation

Hematopoietic cell transplantation (HCT) is an essential component of potentially curative therapy for patients with hematologic malignancies. High-dose chemotherapy with autologous (auto) stem cell rescue is used to overcome chemoresistance in multiple myeloma, non-Hodgkin lymphoma, and Hodgkin lymphoma. Alternatively, poor-risk acute leukemias rely on the graft versus leukemia effect of allogeneic (allo) products. Long-term remissions are feasible with both auto- and allo-HCT; however, disease relapse is the leading cause of death after HCT for many patients. In recognition of this, novel therapies are being investigated in the upfront, relapsed/refractory, and post-HCT maintenance settings to deepen response and maintain disease control. To date, the most robust data to support this approach are in multiple myeloma, where post-transplant maintenance therapy has improved clinical outcomes. In Hodgkin lymphoma, patients with high-risk features may benefit from post-auto-HCT vedotin (BV) regardless of pre-HCT BV exposure. Apart from mantle cell lymphoma, where rituximab maintenance is generally accepted, post-auto-HCT maintenance in other forms of NHL is less established. In patients who undergo allo-HCT, the utilization of maintenance therapy is an important component of improving post-HCT outcomes, however, an individualized approach that considers patient factors such as residual toxicity from HCT, an immature graft with poor graft function, infection, and graft-versus-host disease create a complex environment for aggressive interventions. Initiation of directed agents in patients with identified mutations prior to allo-HCT, including FLT3 in acute myeloid leukemia and Philadelphia chromosome in acute lymphoid leukemia have generally improved post-HCT outcomes. Ongoing studies are exploring the safety and efficacy of additional maintenance strategies post-allo-HCT in an effort to further improve post-HCT outcomes.

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.

Hematopoietic stem cell transplantation for blood cancers in the era of precision medicine and immunotherapy

Hematopoietic stem cell transplantation (HCT) has been an integral component in the treatment of many hematologic malignancies. Since the development of HCT nearly 50 years ago, the role of this modality has evolved as newer treatment approaches have been developed and integrated into the standard of care. In the last decade, novel and highly active targeted therapies and immunotherapies have been approved for many hematologic malignancies, raising the question of whether HCT continues to retain its prominent role in the treatment paradigms of various hematologic malignancies. In this review, the authors have described the current role of autologous and allogeneic HCT in the treatment of patients with acute leukemias, aggressive B-cell lymphomas, and multiple myeloma and discussed how novel targeted therapies and immunotherapies have changed the potential need, timing, and goal of HCT in patients with these diseases.

Trends in the use of hematopoietic stem cell transplantation for adults with acute lymphoblastic leukemia in Europe: a report from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation (EBMT)

Hematopoietic stem cell transplantation (HSCT) is considered an effective way to prevent relapse in adults with acute lymphoblastic leukemia (ALL). This study aimed to assess general trends in the use of various types of HSCTs performed between 2001 and 2015 in Europe, based on data reported to the European Society for Blood and Marrow Transplantation registry. We also evaluated HSCT rates with respect to ALL incidence in selected countries. Altogether, 15,346 first allogeneic (n = 13,460) or autologous (n = 1886) HSCTs were performed in the study period. Comparing 2013–2015 and 2001–2003, the number of allogeneic HSCTs performed in first complete remission increased by 136%, most prominently for transplantations from unrelated (272%) and mismatched related donors (339%). The number of HSCTs from matched sibling donors increased by 42%, while the total number of autologous HSCTs decreased by 70%. Increased use of allogeneic HSCT was stronger for Philadelphia chromosome (Ph)-positive (166%) than for Ph-negative ALL (38%) and for patients aged > 55 years (599%) than for younger adults (59%). The proportion of allogeneic HSCT with reduced-intensity conditioning (RIC) increased from 6 to 27%. The age-standardized rates of allogeneic HSCT per ALL incidence varied strongly among countries. Our analysis showed a continued trend toward increased allogeneic HSCT use for adults with ALL, which may be attributed to increasing availability of unrelated donors, wider use of RIC regimens, and improving efficacy of pretransplant therapy, including tyrosine kinase inhibitors for Ph-positive ALL. Allogeneic HSCT remains a major tool in the fight against ALL in adults.

Treatment and monitoring of Philadelphia chromosome-positive leukemia patients: recent advances and remaining challenges

The Philadelphia (Ph) chromosome, resulting from the t(9;22)(q34;q11) translocation, can be found in chronic myeloid leukemia (CML) as well as in a subset of acute lymphoblastic leukemias (ALL). The deregulated BCR-ABL1 tyrosine kinase encoded by the fusion gene resulting from the translocation is considered the pathogenetic driver and can be therapeutically targeted. In both CML and Ph-positive (Ph+) ALL, tyrosine kinase inhibitors (TKIs) have significantly improved outcomes. In the TKI era, testing for BCR-ABL1 transcript levels by real-time quantitative polymerase chain reaction (RQ-PCR) has become the gold standard to monitor patient response, anticipate relapse, and guide therapeutic decisions. In CML, key molecular response milestones have been defined that draw the ideal trajectory towards optimal long-term outcomes. Treatment discontinuation (treatment-free remission, TFR) has proven feasible in a proportion of patients, and clinical efforts are now focused on how to increase this proportion and how to best select TFR candidates. In Ph+ ALL, results of trials with second- and third-generation TKIs are challenging the role of intensive chemotherapy and even that of allogeneic stem cell transplantation. Additional weapons are offered by the recently introduced monoclonal antibodies. In patients harboring mutations in the BCR-ABL1 kinase domain, prompt therapeutic reassessment and individualization based on mutation status are important to regain response and prevent disease progression. Next-generation sequencing is likely to become a precious tool for mutation testing because of the greater sensitivity and the possibility to discriminate between compound and polyclonal mutations. In this review, we discuss the latest advances in treatment and monitoring of CML and Ph+ ALL and the issues that still need to be addressed to make the best use of the therapeutic armamentarium and molecular testing technologies currently at our disposal.

Immune cell constitution in bone marrow microenvironment predicts outcome in adult ALL

As novel immunological treatments are gaining a foothold in the treatment of acute lymphoblastic leukemia (ALL), it is elemental to examine ALL immunobiology in more detail. We used multiplexed immunohistochemistry (mIHC) to study the immune contexture in adult precursor B cell ALL bone marrow (BM). In addition, we developed a multivariate risk prediction model that stratified a poor survival group based on clinical parameters and mIHC data. We analyzed BM biopsy samples of ALL patients (n = 52) and healthy controls (n = 14) using mIHC with 30 different immunophenotype markers and computerized image analysis. In ALL BM, the proportions of M1-like macrophages, granzyme B+CD57+CD8+ T cells, and CD27+ T cells were decreased, whereas the proportions of myeloid-derived suppressor cells and M2-like macrophages were increased. Also, the expression of checkpoint molecules PD1 and CTLA4 was elevated. In the multivariate model, age, platelet count, and the proportion of PD1+TIM3+ double-positive CD4+ T cells differentiated a poor survival group. These results were validated by flow cytometry in a separate cohort (n = 31). In conclusion, the immune cell contexture in ALL BM differs from healthy controls. CD4+PD1+TIM3+ T cells were independent predictors of poor outcome in our multivariate risk model, suggesting that PD1 might serve as an attractive immuno-oncological target in B-ALL.

Impact of anti-thymocyte globulin on results of allogeneic peripheral blood stem cell transplantation for patients with Philadelphia-positive acute lymphoblastic leukaemia: An analysis by the Acute Leukemia Working Party of the EBMT

BACKGROUND

Anti-thymocyte globulin (ATG) is widely used to prevent graft-versus-host disease (GVHD) after allogeneic peripheral blood stem cell transplantation (alloPBSCT). The goal of this study was to retrospectively assess the effect of ATG on outcomes in the setting of Philadelphia chromosome-positive acute lymphoblastic leukaemia (Ph+ ALL).

METHODS

In the analysis, 1170 adult patients undergoing alloPBSCT from human leucocyte antigen-matched sibling or unrelated donors in the first complete remission between 2007 and 2016 were included. ATG was used in 429/575 (75%) and 121/595 (20%) patients transplanted from unrelated or sibling donors, respectively.

RESULTS

The incidence of chronic GVHD was 35% for patients treated with ATG compared with 52% in those not receiving ATG (p < 0.001), while the rate of extensive chronic GVHD was 16% and 36%, respectively (p < 0.001). The probability of survival free from GVHD and relapse (GRFS) was 42% and 32%, respectively (p = 0.002). In a multivariate model, the use of ATG was associated with reduced risk of overall chronic GVHD (hazard ratio [HR] = 0.52, p < 0.001) and extensive chronic GVHD (HR = 0.46, p < 0.001). It was also associated with better GRFS (HR = 0.77, p = 0.007), despite increased risk of relapse (HR = 1.41, p = 0.02). No significant effect was found with regard to the risk of non-relapse mortality and overall mortality.

CONCLUSIONS

The use of ATG for patients with Ph+ ALL undergoing alloPBSCT is associated with reduced risk of chronic GVHD without impact on survival and therefore, could be considered. However, increased risk of relapse suggests the need for strict monitoring of minimal residual diseases and appropriate interventions after transplantation.

Prognostic implications of additional genomic lesions in adult Philadelphia chromosome-positive acute lymphoblastic leukemia

To shed light onto the molecular basis of Philadelphia chromosome-positive acute lymphoblastic leukemia and to investigate the prognostic role of additional genomic lesions, we analyzed copy number aberrations using the Cytoscan HD Array in 116 newly diagnosed adult patients with Philadelphia chromosome-positive acute lymphoblastic leukemia enrolled in four different GIMEMA protocols, all based on a chemotherapy-free induction strategy. This analysis showed that patients with Philadelphia chromosome-positive acute lymphoblastic leukemia carry an average of 7.8 lesions/case, with deletions outnumbering gains (88% versus 12%). The most common deletions were those targeting IKZF1, PAX5 and CDKN2A/B, which were detected in 84%, 36% and 32% of cases, respectively. Patients carrying simultaneous deletions of IKZF1 plus CDKN2A/B and/or PAX5 had a significantly lower disease-free survival rate (24.9% versus 43.3%; P=0.026). The only IKZF1 isoform affecting prognosis was the dominant negative one (P=0.003). Analysis of copy number aberrations showed that 18% of patients harbored MEF2C deletions, which were of two types, differing in size: the longer deletions were associated with the achievement of a complete molecular remission (P=0.05) and had a favorable impact on disease-free survival (64.3% versus 32.1% at 36 months; P=0.031). These findings retained statistical significance also in multivariate analysis (P=0.057). KRAS deletions, detected in 6% of cases, were associated with the achievement of a complete molecular remission (P=0.009). These results indicate that in adults with Philadelphia chromosome-positive acute lymphoblastic leukemia a detailed evaluation of additional deletions - including CDKN2A/B, PAX5, IKZF1, MEF2C and KRAS - has prognostic implications and should be incorporated in the design of more personalized treatment strategies.

Comparable results of autologous and allogeneic haematopoietic stem cell transplantation for adults with Philadelphia-positive acute lymphoblastic leukaemia in first complete molecular remission: An analysis by the Acute Leukemia Working Party of the EBMT

BACKGROUND

Allogeneic haematopoietic stem cell transplantation (alloHSCT) is considered a standard treatment for patients with Philadelphia chromosome-positive acute lymphoblastic leukaemia (Ph+ ALL) achieving complete remission after induction containing tyrosine kinase inhibitors (TKIs).

METHODS

We retrospectively compared results of myeloablative alloHSCT from either matched sibling donor (MSD) or unrelated donor (URD) with autologous (auto) HSCT for adults with Ph+ ALL in molecular remission, treated between 2007 and 2014.

RESULTS

In univariate analysis, the incidence of relapse at 2 years was 47% after autoHSCT, 28% after MSD-HSCT and 19% after URD-HSCT (P = 0.0002). Respective rates of non-relapse mortality were 2%, 18%, and 22% (P = 0.001). The probabilities of leukaemia-free survival were 52%, 55% and 60% (P = 0.69), while overall survival rates were 70%, 70% and 69% (P = 0.58), respectively. In multivariate analysis, there was a trend towards increased risk of overall mortality after MSD-HSCT (hazard ratio [HR], 1.5, P = 0.12) and URD-HSCT (HR, 1.6, P = 0.08) when referred to autoHSCT. The use of total body irradiation (TBI)-based regimens was associated with reduced risk of relapse (HR, 0.65, P = 0.02) and overall mortality (HR, 0.67, P = 0.01).

CONCLUSION

In the era of TKIs, outcomes of myeloablative autoHSCT and alloHSCT for patients with Ph+ ALL in first molecular remission are comparable. Therefore, autoHSCT appears to be an attractive treatment option potentially allowing for circumvention of alloHSCT sequelae. Irrespective of the type of donor, TBI-based regimens should be considered the preferable type of conditioning for Ph+ ALL.

Efficacy of Ponatinib Versus Earlier Generation Tyrosine Kinase Inhibitors for Front-line Treatment of Newly Diagnosed Philadelphia-positive Acute Lymphoblastic Leukemia

INTRODUCTION

Complete molecular response (CMR) and 2- and 3-year overall survival (OS) were compared for patients with newly diagnosed Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL) who had undergone front-line combination chemotherapy plus ponatinib versus combination therapy plus earlier generation tyrosine kinase inhibitors (TKIs; imatinib, dasatinib, and nilotinib).

PATIENTS AND METHODS

We identified 26 Ph+ ALL studies: 25 of earlier generation TKIs and 1 of ponatinib. The outcomes from studies of combination chemotherapy plus earlier generation TKIs were summarized using pooled estimates with 95% confidence intervals (CIs) from a random-effects meta-analysis. A binomial distribution was assumed to calculate the 95% CIs for the results from the single-arm combination chemotherapy plus ponatinib trial. Adjusted logistic meta-regression analyses were used to compare the outcomes between the TKI groups.

RESULTS

The percentage of patients achieving a CMR was greater with combination chemotherapy plus ponatinib (79%) than the pooled percentage of patients achieving a CMR with combination chemotherapy plus earlier generation TKIs (34%). Greater OS was observed with ponatinib compared with the pooled OS for earlier generation TKIs (2-year, 83% vs. 58%; 3-year, 79% vs. 50%). Odds ratios for ponatinib versus earlier generation TKIs were 6.09 (95% CI, 1.16-31.90; P = .034) for CMR, 3.70 (95% CI, 0.93-14.73; P = .062) for 2-year OS, and 4.49 (95% CI, 1.00-20.13; P = .050) for 3-year OS.

CONCLUSION

Ponatinib plus chemotherapy might be associated with better outcomes than chemotherapy with earlier generation TKIs in patients with newly diagnosed Ph+ ALL.