Efficacy and safety analysis by age cohort of inotuzumab ozogamicin in patients with relapsed or refractory acute lymphoblastic leukemia enrolled in INO-VATE

BACKGROUND

Inotuzumab ozogamicin (InO) has demonstrated efficacy and tolerability in patients aged 18 to 78 years with relapsed/refractory acute lymphoblastic leukemia (ALL) in the INO-VATE trial. This subset analysis compared the efficacy and safety of InO in younger and older patients.

METHODS

Intent-to-treat analyses of morphologic responses and overall survival (OS) included 326 randomized patients, and safety assessments included 307 patients receiving 1 or more doses of the study treatment. Of the 326 patients, 164 received InO at a starting dose of 1.8 mg/m² /cycle (0.8 mg/m² on day 1 and 0.5 mg/m² on days 8 and 15 of a 21- to 28-day cycle [≤6 cycles]); 60 patients were aged ≥55 years, and 104 were aged <55 years.

RESULTS

For older and younger patients, the median duration of InO therapy and the types and frequencies of adverse events of any grade were generally similar. Although the remission rates, median duration of remission (DOR), and progression-free survival were similar with InO for those aged <55 years and those aged ≥55 years, OS was longer for younger patients (median, 8.6 vs 5.6 months; hazard ratio, 0.610). Among patients proceeding to hematopoietic stem cell transplantation after InO treatment (28% of older patients and 58% of younger patients), the incidence of veno-occlusive disease was greater in older patients (41% vs 17%). The study database was not locked at the time of this analysis.

CONCLUSIONS

InO was tolerable in older patients with relapsed/refractory ALL. Although OS was longer for younger patients versus older patients, InO demonstrated high response rates with similar DOR in the 2 age groups. Cancer 2018;124:1722-32. © 2018 American Cancer Society.

Randomized comparison of liposomal amphotericin B versus placebo to prevent invasive mycoses in acute lymphoblastic leukaemia

Objectives

To prevent invasive fungal disease (IFD) in adult patients undergoing remission-induction chemotherapy for newly diagnosed acute lymphoblastic leukaemia (ALL).

Patients and methods

In a double-blind multicentre Phase 3 study, patients received prophylactic liposomal amphotericin B (L-AMB) at 5 mg/kg intravenously or placebo twice weekly in a 2:1 random allocation during remission-induction treatment. The primary endpoint was the development of proven or probable IFD. Secondary endpoints included those focused on the safety and tolerability of prophylactic L-AMB.

Results

Three hundred and fifty-five patients from 86 centres in Europe and South America received at least one dose of L-AMB ( n =  237) or placebo ( n =  118). Rates of proven and probable IFD assessed independently were 7.9% (18/228) in the L-AMB group and 11.7% (13/111) in the placebo group ( P  =   0.24). Rates of possible IFD were 4.8% (11/228) in the L-AMB and 5.4% (6/111) in the placebo group ( P  =   0.82). The remission-induction phase was a median of 22 days for both groups. Overall mortality was similar between the groups: 7.2% (17/237) for L-AMB and 6.8% (8/118) for placebo ( P  =   1.00). Hypokalaemia and creatinine increase were significantly more frequent with L-AMB.

Conclusions

The IFD rate among adult patients undergoing remission-induction chemotherapy for newly diagnosed ALL was 11.7% in the placebo group, and was not significantly different in patients receiving L-AMB, suggesting that the L-AMB regimen studied is not effective as prophylaxis against IFD. The IFD rate appears higher than previously reported, warranting further investigation. Tolerability of L-AMB was what might be expected. Further studies are needed to determine the optimal antifungal strategy during remission-induction chemotherapy of ALL.

Blinatumomab for minimal residual disease in adults with B-cell precursor acute lymphoblastic leukemia

Approximately 30% to 50% of adults with acute lymphoblastic leukemia (ALL) in hematologic complete remission after multiagent therapy exhibit minimal residual disease (MRD) by reverse transcriptase-polymerase chain reaction or flow cytometry. MRD is the strongest predictor of relapse in ALL. In this open-label, single-arm study, adults with B-cell precursor ALL in hematologic complete remission with MRD (≥10^-3) received blinatumomab 15 µg/m² per day by continuous IV infusion for up to 4 cycles. Patients could undergo allogeneic hematopoietic stem-cell transplantation any time after cycle 1. The primary end point was complete MRD response status after 1 cycle of blinatumomab. One hundred sixteen patients received blinatumomab. Eighty-eight (78%) of 113 evaluable patients achieved a complete MRD response. In the subgroup of 110 patients with Ph-negative ALL in hematologic remission, the Kaplan-Meier estimate of relapse-free survival (RFS) at 18 months was 54%. Median overall survival (OS) was 36.5 months. In landmark analyses, complete MRD responders had longer RFS (23.6 vs 5.7 months; P = .002) and OS (38.9 vs 12.5 months; P = .002) compared with MRD nonresponders. Adverse events were consistent with previous studies of blinatumomab. Twelve (10%) and 3 patients (3%) had grade 3 or 4 neurologic events, respectively. Four patients (3%) had cytokine release syndrome grade 1, n = 2; grade 3, n = 2), all during cycle 1. After treatment with blinatumomab in a population of patients with MRD-positive B-cell precursor ALL, a majority achieved a complete MRD response, which was associated with significantly longer RFS and OS compared with MRD nonresponders. This study is registered at www.clinicaltrials.gov as #NCT01207388.

Cell adhesion-mediated mitochondria transfer contributes to mesenchymal stem cell-induced chemoresistance on T cell acute lymphoblastic leukemia cells

BACKGROUND

Despite the high cure rate of T cell acute lymphoblastic leukemia (T-ALL), drug resistance to chemotherapy remains a significant clinical problem. Bone marrow mesenchymal stem cells (MSCs) protect leukemic cells from chemotherapy, but the underlying mechanisms are poorly understood. In this study, we aimed to uncover the mechanism of MSC-induced chemoresistance in T-ALL cells, thus providing a promising clinical therapy target.

METHODS

Cell viability was determined using the viability assay kit CCK-8. The mitochondrial ROS levels were detected using the fluorescent probe MitoSOX™ Red, and fluorescence intensity was measured by flow cytometry. In vitro, MSCs and Jurkat cells were cocultured. MSCs were labeled with green fluorescent protein (GFP), and Jurkat cells were labeled with the mitochondria-specific dye MitoTracker Red. Bidirectional mitochondrial transfer was detected by flow cytometry and confocal microscopy. The mechanism of mitochondria transfer was analyzed by inhibitor assays. Transcripts related to Jurkat cell/MSC adhesion in the coculture system were assessed by qRT-PCR. After treatment with a neutralizing antibody against a key adhesion molecule, mitochondria transfer from Jurkat cells to MSCs was again detected by flow cytometry and confocal microscopy. Finally, we verified our findings using human primary T-ALL cells cocultured with MSCs.

RESULTS

Chemotherapeutic drugs caused intracellular oxidative stress in Jurkat cells. Jurkat cells transfer mitochondria to MSCs but receive few mitochondria from MSCs, resulting in chemoresistance. This process of mitochondria transfer is mediated by tunneling nanotubes, which are protrusions that extend from the cell membrane . Moreover, we found that most Jurkat cells adhered to MSCs in the coculture system, which was mediated by the adhesion molecule ICAM-1. Treatment with a neutralizing antibody against ICAM-1 led to a decreased number of adhering Jurkat cells, decreased mitochondria transfer, and increased chemotherapy-induced cell death.

CONCLUSIONS

We show evidence that mitochondria transfer from Jurkat cells to MSCs, which is mediated by cell adhesion, may be a potential therapeutic target for T-ALL treatment.

Genomic CDKN2A/2B deletions in adult Ph+ ALL are adverse despite allogeneic stem cell transplantation

We investigated the role of copy number alterations to refine risk stratification in adult Philadelphia chromosome positive (Ph)⁺ acute lymphoblastic leukemia (ALL) treated with tyrosine kinase inhibitors (TKIs) and allogeneic stem cell transplantation (aSCT). Ninety-seven Ph⁺ ALL patients (median age 41 years; range 18-64 years) within the prospective multicenter German Multicenter ALL Study Group studies 06/99 (n = 8) and 07/2003 (n = 89) were analyzed. All patients received TKI and aSCT in first complete remission (CR1). Copy number analysis was performed with single nucleotide polymorphism arrays and validated by multiplex ligation-dependent probe amplification. The frequencies of recurrently deleted genes were: IKZF1, 76%; CDKN2A/2B, 45%; PAX5, 43%; BTG1, 18%; EBF1, 13%; ETV6, 5%; RB, 14%. In univariate analyses, the presence of CDKN2A/2B deletions had a negative impact on all endpoints: overall survival (P = .023), disease-free survival (P = .012), and remission duration (P = .036). The negative predictive value of CDKN2A/2B deletions was retained in multivariable analysis along with other factors such as timing of TKI therapy, intensity of conditioning, achieving remission after induction phase 1 and BTG1 deletions. We therefore conclude that acquired genomic CDKN2A/2B deletions identify a subgroup of Ph⁺ ALL patients, who have an inferior prognosis despite aSCT in CR1. Their poor outcome was attributable primarily to a high relapse rate after aSCT.

The histone demethylase PHF8 promotes adult acute lymphoblastic leukemia through interaction with the MEK/ERK signaling pathway

Adult acute lymphoblastic leukemia (ALL) is a malignant disorder of lymphoid progenitor cells that is associated with a high risk of relapse and poor prognosis. Thus, novel pathogenic mechanisms and therapeutic targets need to be explored. Histone methylation is one of the most significant chromatin post-translational modifications. Here, we show that the histone demethylase PHF8 is highly expressed in a large number of ALL clinical specimens and that PHF8 expression is associated with ALL progression. PHF8 knockdown inhibits proliferation and promotes the apoptosis of ALL cells in vitro as well as attenuates tumor growth in vivo. PHF8 transcriptionally upregulates MEK1, a key molecule in the MEK/ERK pathway, at least partially by directly binding to its promoter, thereby activating the MEK/ERK pathway. In addition, we found that an inhibitor of the MEK/ERK pathway, PD184352, subsequently suppresses PHF8 expression. Thus, PHF8 forms a positive feedback loop with the MEK/ERK pathway, and PHF8 knockdown enhances the lethality of PD184352 in ALL cells. In conclusion, this study identifies oncogenic functions of PHF8 in adult ALL and suggests a novel epigenetic strategy for disease intervention.

Calcineurin complex isolated from T-cell acute lymphoblastic leukemia (T-ALL) cells identifies new signaling pathways including mTOR/AKT/S6K whose inhibition synergize with calcineurin inhibition to promote T-ALL cell death

Calcineurin (Cn) is a calcium activated protein phosphatase involved in many aspects of normal T cell physiology, however the role of Cn and/or its downstream targets in leukemogenesis are still ill-defined. In order to identify putative downstream targets/effectors involved in the pro-oncogenic activity of Cn in T-cell acute lymphoblastic leukemia (T-ALL) we used tandem affinity chromatography, followed by mass spectrometry to purify novel Cn-interacting partners. We found the Cn-interacting proteins to be part of numerous cellular signaling pathways including eIF2 signaling and mTOR signaling. Coherently, modulation of Cn activity in T-ALL cells determined alterations in the phosphorylation status of key molecules implicated in protein translation such as eIF-2α and ribosomal protein S6. Joint targeting of PI3K-mTOR, eIF-2α and 14-3-3 signaling pathways with Cn unveiled novel synergistic pro-apoptotic drug combinations. Further analysis disclosed that the synergistic interaction between PI3K-mTOR and Cn inhibitors was prevalently due to AKT inhibition. Finally, we showed that the synergistic pro-apoptotic response determined by jointly targeting AKT and Cn pathways was linked to down-modulation of key anti-apoptotic proteins including Mcl-1, Claspin and XIAP. In conclusion, we identify AKT inhibition as a novel promising drug combination to potentiate the pro-apoptotic effects of Cn inhibitors.

Loss of T-cell quiescence by targeting Slfn2 prevents the development and progression of T-ALL

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy of thymocytes. Despite significant improvement in the treatment of T-ALL, approximately 20% of children and most adults undergo relapse. Previous findings demonstrated that loss of T-cell quiescence due to a mutation in the Slfn2 gene (elektra) leads to acquisition of an aberrant developmental program by which T-cells lose their renewal capabilities and undergo apoptosis. Here we show that the elektra mutation in Slfn2 completely prevents a severe lymphoproliferative disease caused by overexpression of BCL2 in combination with Fas deficiency in mice. Moreover, Slfn2 impaired-function protects mice from experimental disease similar to human T-ALL by severely impairing the proliferation potential and survival of leukemic T-cells, partially by activation of the p53 tumor suppressor protein. Our study suggest that in certain malignancies, such as T-ALL, a novel therapeutic strategy may be applied by imposing aberrant development of leukemic cells. Furthermore, as the elektra mutation in Slfn2 seems to impair only T-cells and monocytes, targeting Slfn2 is expected to be harmless to other cell types, and thereby could be a promising target for treating malignancies. Together our results demonstrate the potential of targeting Slfn2 and its human paralog for T-ALL treatment.

Dual Targeting of Acute Leukemia and Supporting Niche by CXCR4-Directed Theranostics

C-X-C chemokine receptor 4 (CXCR4) is a transmembrane receptor with pivotal roles in cell homing and hematopoiesis. CXCR4 is also involved in survival, proliferation and dissemination of cancer, including acute lymphoblastic and myeloid leukemia (ALL, AML). Relapsed/refractory ALL and AML are frequently resistant to conventional therapy and novel highly active strategies are urgently needed to overcome resistance. Methods: We used patient-derived (PDX) and cell line-based xenograft mouse models of ALL and AML to evaluate the efficacy and toxicity of a CXCR4-targeted endoradiotherapy (ERT) theranostic approach. Results: The positron emission tomography (PET) tracer 68Ga-Pentixafor enabled visualization of CXCR4 positive leukemic burden. In xenografts, CXCR4-directed ERT with 177Lu-Pentixather distributed to leukemia harboring organs and resulted in efficient reduction of leukemia. Despite a substantial in vivo cross-fire effect to the leukemia microenvironment, mesenchymal stem cells (MSCs) subjected to ERT were viable and capable of supporting the growth and differentiation of non-targeted normal hematopoietic cells ex vivo. Finally, three patients with refractory AML after first allogeneic hematopoietic stem cell transplantation (alloSCT) underwent CXCR4-directed ERT resulting in leukemia clearance, second alloSCT, and successful hematopoietic engraftment. Conclusion: Targeting CXCR4 with ERT is feasible and provides a highly efficient means to reduce refractory acute leukemia for subsequent cellular therapies. Prospective clinical trials testing the incorporation of CXCR4 targeting into conditioning regimens for alloSCT are highly warranted.

Prognostic and therapeutic role of targetable lesions in B-lineage acute lymphoblastic leukemia without recurrent fusion genes

To shed light into the molecular bases of B-lineage acute lymphoblastic leukemia lacking known fusion transcripts, i.e. BCR-ABL1, ETV6-RUNX1, E2A-PBX1, and MLL rearrangements (B-NEG ALL) and the differences between children, adolescents/young adults (AYA) and adults, we analyzed 168 B-NEG ALLs by genome-wide technologies. This approach showed that B-NEG cases carry 10.5 mutations and 9.1 copy-number aberrations/sample. The most frequently mutated druggable pathways were those pertaining to RAS/RTK (26.8%) and JAK/STAT (12.5%) signaling. In particular, FLT3 and JAK/STAT mutations were detected mainly in AYA and adults, while KRAS and NRAS mutations were more frequent in children. RAS/RTK mutations negatively affected the outcome of AYA and adults, but not that of children. Furthermore, adult B-NEG ALL carrying JAK/STAT mutations had a shorter survival. In vitro experiments showed that FLT3 inhibitors reduced significantly the proliferation of FLT3-mutated primary B-NEG ALL cells. Likewise, PI3K/mTOR inhibitors reduced the proliferation of primary cells harboring RAS and IL7R mutations. These results refine the genetic landscape of B-NEG ALL and suggest that the different distribution of lesions and their prognostic impact might sustain the diverse outcome between children, adults and partly AYA - whose genomic scenario is similar to adults - and open the way to targeted therapeutic strategies.

Primary prophylaxis of invasive fungal infections in patients with haematological malignancies: 2017 update of the recommendations of the Infectious Diseases Working Party (AGIHO) of the German Society for Haematology and Medical Oncology (DGHO)

Immunocompromised patients are at high risk of invasive fungal infections (IFI), in particular those with haematological malignancies undergoing remission-induction chemotherapy for acute myeloid leukaemia (AML) or myelodysplastic syndrome (MDS) and recipients of allogeneic haematopoietic stem cell transplants (HSCT). Despite the development of new treatment options in the past decades, IFI remains a concern due to substantial morbidity and mortality in these patient populations. In addition, the increasing use of new immune modulating drugs in cancer therapy has opened an entirely new spectrum of at risk periods. Since the last edition of antifungal prophylaxis recommendations of the German Society for Haematology and Medical Oncology in 2014, seven clinical trials regarding antifungal prophylaxis in patients with haematological malignancies have been published, comprising 1227 patients. This update assesses the impact of this additional evidence and effective revisions. Our key recommendations are the following: prophylaxis should be performed with posaconazole delayed release tablets during remission induction chemotherapy for AML and MDS (AI). Posaconazole iv can be used when the oral route is contraindicated or not feasible. Intravenous liposomal amphotericin B did not significantly decrease IFI rates in acute lymphoblastic leukaemia (ALL) patients during induction chemotherapy, and there is poor evidence to recommend it for prophylaxis in these patients (CI). Despite substantial risk of IFI, we cannot provide a stronger recommendation for these patients. There is poor evidence regarding voriconazole prophylaxis in patients with neutropenia (CII). Therapeutic drug monitoring TDM should be performed within 2 to 5 days of initiating voriconazole prophylaxis and should be repeated in case of suspicious adverse events or of dose changes of interacting drugs (BIItu). General TDM during posaconazole prophylaxis is not recommended (CIItu), but may be helpful in cases of clinical failure such as breakthrough IFI for verification of compliance or absorption.

Retrospective chart review of hospitalizations and costs associated with the treatment of adults with Philadelphia-negative B-cell relapsed or refractory acute lymphoblastic leukemia in Belgium

OBJECTIVES

To quantify hospitalizations and costs among adults with Philadelphia-negative relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (ALL) who received current salvage chemotherapies in Belgium.

METHODS

A retrospective chart review identified patients aged ≥18 years and hospitalized between 2005 and 2015 for Ph-negative R/R B-cell ALL. Data were collected from the index date (first diagnosis of R/R ALL) until death or loss to follow-up. The salvage chemotherapy period was defined as the first chemotherapy hospitalization after the index date to the earliest of death, loss to follow-up, last chemotherapy dose plus 30 days, or initiation of hematological stem cell transplantation (HSCT). The primary endpoint was the percent of time in the hospital during the salvage chemotherapy period. Hospitalization costs were reported from the public health care payer perspective.

RESULTS

Nineteen patients were included, with median age of 37 years. The average proportion of time patients spent in the hospital during the salvage chemotherapy period was 50.5%. From the index date to death, patients received a mean of 1.8 lines of chemotherapy, most commonly hyper-CVAD (31%). There was a mean of 5.5 inpatient hospitalizations and 40.1 outpatient visits with 40.8 outpatient lab tests. Mean costs per patient were €79,973 for hospitalization (excluding HSCT), €26,337 for HSCT, €21,007 for chemotherapy drugs, and €6,341 for outpatient management, resulting in a total cost from the payer's perspective of €133,965 per patient.

CONCLUSION

Adults with Ph-negative R/R ALL spend half the time receiving salvage chemotherapy in the hospital. Their treatment is associated with large reimbursement costs in Belgium.

Prognostic relevance of HER2/neu in acute lymphoblastic leukemia and induction of NK cell reactivity against primary ALL blasts by trastuzumab

The epidermal growth factor receptor HER2/neu is expressed on various cancers and represents a negative prognostic marker, but is also a target for the therapeutic monoclonal antibody Trastuzumab. In about 30% of cases, HER2/neu is expressed on acute lymphoblastic leukemia (ALL) cells and was proposed to be associated with a deleterious prognosis. Here we evaluated clinical data from 65 ALL patients (HER2/neu+, n = 17; HER2/neu-, n = 48) with a median follow-up of 19.4 months (range 0.6-176.5 months) and observed no association of HER2/neu expression with response to chemotherapy, disease free or overall survival. In vitro, treatment of primary ALL cells (CD20+HER2/neu+, CD20+HER2/neu- and CD20-HER2/neu-) with Rituximab and Trastuzumab led to activation of NK cells in strict dependence of the expression of the respective antigen. NK reactivity was more pronounced with Rituximab as compared to Trastuzumab, and combined application could lead to additive effects in cases where both antigens were expressed. Besides providing evidence that HER2/neu expression is no risk factor in ALL patients, our data demonstrates that HER2/neu can be a promising target for Trastuzumab therapy in the subset of ALL patients with the potential to improve disease outcome.

High mTOR expression independently prognosticates poor clinical outcome to induction chemotherapy in acute lymphoblastic leukemia

In acute lymphoblastic leukemia (ALL), limited data are available on mTOR gene expression in clinical samples and its role in predicting response to induction chemotherapy. mRNA expression of mTOR gene was determined quantitatively by real-time PCR in 50 ALL patients (30 B-ALL and 20 T-ALL) and correlated with clinical outcome after induction chemotherapy. Expression level of mTOR was upregulated in more than 50% of cases of ALL. In T-ALL, high expression of mTOR was commonly seen, more in adults than children (82 vs. 55% cases), while in B-ALL it was same (~ 63% cases) in both adults and children. Mean fold change of mTOR expression was significantly higher in non-responders compared to responders of both adult B-ALL (7.4 vs. 2.7, p = 0.05) and T-ALL (13.9 vs. 2.4, p = 0.001). Similar results were seen in pediatric non-responders when compared to responders of both B-ALL (14.5 vs. 2.5, p = 0.006) and T-ALL (24.2 vs. 1.7, p = 0.002). Interestingly, we have observed that mTOR expression was two times higher in non-responders of children compared to adults in both B-ALL (14.5 vs. 7.4, p = 0.05) and T-ALL (24.2 vs. 13.9, p = 0.01). Multivariate analysis with other known prognostic factors revealed that mTOR expression independently predicts clinical response to induction chemotherapy in ALL. This study demonstrates that high mTOR expression is associated with poor clinical outcome in ALL and can serve as a potential target for novel therapeutic strategies.

The presence of Philadelphia chromosome does not confer poor prognosis in adult pre-B acute lymphoblastic leukaemia in the tyrosine kinase inhibitor era - a surveillance, epidemiology, and end results database analysis

The BCR-ABL1 fusion gene is caused by a translocation between chromosomes 9 and 22, resulting in an abnormal chromosome 22 (Philadelphia chromosome; Ph). Prior to the introduction of tyrosine kinase inhibitors (TKI), the presence of BCR-ABL1 conferred a poor prognosis in patients with acute lymphoblastic leukaemia (ALL). We compared the survival of Ph+ and Ph-ALL during the period when TKIs were universally available in the US for Ph+ALL, using a Surveillance, Epidemiology, and End Results (SEER) Database analysis. A total of 2694 patients with pre-B ALL (206 Ph+ALL; 2488 Ph-ALL) aged ≥18 years, who were diagnosed between 2010 and 2014, were identified in SEER registries. The median overall survival (OS) was 32 months in Ph+ALL (95% confidence interval [CI] 18 months-not reached) and 27 months (95% CI 24-30 months) in Ph-ALL (Log-rank test P-value 0·34). Older age was associated with worse prognosis in both Ph+ALL and Ph-ALL. Age-adjusted OS was inferior in Hispanics and African-Americans compared to non-Hispanic whites. Survival of pre-B ALL shows continued improvement with time. Philadelphia chromosome status does not confer poor prognosis in pre-B ALL in the TKI era: prognostic factors in pre-B ALL should be re-evaluated in the light of this finding.

Efficacy and safety of G-CSF, low-dose cytarabine and aclarubicin in combination with l-asparaginase, prednisone in the treatment of refractory or relapsed acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) patients who fail to acquire complete remission (CR) or who relapse after initial response have poor prognosis. At present there is no consensus as to the standard salvage therapy for these patients. In this study, we retrospectively evaluate safety and efficacy of a salvage regimen (CAGLP) consisting of G-CSF, low-dose cytarabine, aclarubicin, l-asparaginase and prednisone. Thirty-six patients were included with primary refractory (n=13) or relapse (n=23). The overall response rate (ORR) and CR rate were 86.1% and 63.9%, respectively. With a median follow-up of 34 months, the probability of overall survival (OS) at 2 years was 30%±10% and the disease-free survival (DFS) rate was 15%±8%. Treatment-related mortality was 5.6%. Our preliminary results indicated that CAGLP was feasible, safe and effective as a salvage reinduction chemotherapy for primary refractory and relapsed ALL patients.

The Approach to Acute Lymphoblastic Leukemia in Older Patients: Conventional Treatments and Emerging Therapies

Acute lymphoblastic leukemia (ALL) among older adult patients presents significant clinical challenges. As opposed to pediatric populations, in whom long-term outcomes are markedly superior, those for adults remain grim. Nevertheless, younger adults with ALL have experienced a steady improvement in long-term survival in the last few decades. This is significantly different for older ALL patients, for whom long-term outcomes remain poor. Conventional chemotherapies are associated with sub-optimal outcomes and increased toxicity in this population. However, several emerging therapies, including antibody-drug conjugates, bi-specific engagers, and chimeric antigen receptor (CAR) T cells, have demonstrated much promise and are either incorporated into the existing therapeutic paradigms or being actively investigated to improve outcomes.

Leukemia-Initiating Cells in T-Cell Acute Lymphoblastic Leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is a hematological malignancy characterized by the clonal proliferation of immature T-cell precursors. T-ALL has many similar pathophysiological features to acute myeloid leukemia, which has been extensively studied in the establishment of the cancer stem cell (CSC) theory, but the CSC concept in T-ALL is still debatable. Although leukemia-initiating cells (LICs), which can generate leukemia in a xenograft setting, have been found in both human T-ALL patients and animal models, the nature and origin of LICs are largely unknown. In this review, we discuss recent studies on LICs in T-ALL and the potential mechanisms of LIC emergence in this disease. We focus on the oncogenic transcription factors TAL1, LMO2, and NOTCH1 and highlight the significance of the transcriptional regulatory programs in normal hematopoietic stem cells and T-ALL.

GATA4 is highly expressed in childhood acute lymphoblastic leukemia, promotes cell proliferation and inhibits apoptosis by activating BCL2 and MDM2

Members of the GATA‑binding factor protein family, including GATA1, GATA2 and GATA3, serve an inhibiting role in leukemia. The present study demonstrated that GATA4 was upregulated in children with acute lymphoblastic leukemia (ALL). Results from a number of functional experiments, including cell proliferation analysis, cell cycle analysis, cell apoptosis assay and Transwell migration and invasion analyses, have suggested that high expression of GATA4 may facilitate proliferation and metastasis, and suppress apoptosis in ALL cells. Chromatin immunoprecipitation assay and luciferase reporter assay revealed that GATA4 was a transcription factor that activated mouse double minute 2 homolog (MDM2) and B cell lymphoma 2 (BCL2) expression in ALL cells. BCL2 is a key anti‑apoptosis protein that was demonstrated to suppress cell apoptosis. In addition, GATA4 was revealed to regulate p53 through the transcriptional activation of MDM2, subsequently influencing cell cycle and apoptosis. Results from the present study suggested that GATA4 may be a key marker in ALL diagnosis and a potential target of molecular therapy.

Low-dose decitabine enhances chidamide-induced apoptosis in adult acute lymphoblast leukemia, especially for p16-deleted patients through DNA damage

AIM

To investigate the combined action of decitabine (DAC) with chidamide (CS055) on acute lymphoblastic leukemia (ALL) cells.

MATERIALS & METHODS

ALL cell lines as well as primary cells from 17 ALL patients were subjected to different treatments and thereafter cell counting Kit-8 (CCK-8) assay, flow cytometry and western blot were employed to determine IC₅₀, apoptosis and checkpoint kinase 1 and γH2A.X expression.

RESULTS

Low-dose DAC combined with CS055 could effectively kill ALL cells by the reduction of cell viability and induction of apoptosis. This was also observed in primary cells from 17 ALL patients, especially for those with p16 gene deletion. Suppression of checkpoint kinase 1 phosphorylation and upregulation of γH2A.X expression was demonstrated to participate in DAC plus CS055-induced apoptosis.

CONCLUSION

Low-dose DAC could enhance chidamide-induced apoptosis in adult ALL, especially for patients with p16 gene deletion through DNA damage.

Immunotargeting relapsed or refractory precursor B-cell acute lymphoblastic leukemia - role of blinatumomab

Patients with refractory or relapsed (R/R) acute lymphoblastic leukemia (ALL) have a dismal prognosis of around 5% long-term survival when treated with cytotoxic chemotherapy and allogenic stem cell transplantation. T-cell immunobased strategies open up new therapeutic perspectives. Blinatumomab is the first of a new class of antibody constructs that was labeled bispecific T-cell engager (BiTE): it consists of two single chain variable fragment connected with a flexible linker, one side binding CD3, the other CD19. The tight binding and the close proximity to the CD19-positive B-cells and leukemic cells leads to non-major histocompatibility complex-restricted T-cell activation, polyclonal T-cell expansion and direct target cell killing. Applied by continuous infusion, blinatumomab achieves morphological complete response rates ranging from 39% to 69% in R/R ALL patients (compared to 25% after second-line chemotherapy) with prolonged overall survival (blinatumomab median overall survival, 7.7 months vs chemotherapy, 4.0 months). In comparison to conventional cytotoxic second-line protocols blinatumomab has a favorable safety profile. The main adverse event is related to the mode of action of blinatumomab: the induction of a cytokine-release syndrome that can be managed by interruption and/or the application of steroids or tocilizumab. Another typical complication is the occurrence of neurological side effects, such as seizures and encephalopathy. This neurotoxicity is reversible after application of steroids and/or withdrawal of blinatumomab. Blinatumomab has proven to be a powerful therapeutic option in R/R ALL patients both adult and pediatric because of its efficacy and limited toxicity.

Phase II Study of Sequential Infusion of Donor Lymphocyte Infusion and Cytokine-Induced Killer Cells for Patients Relapsed after Allogeneic Hematopoietic Stem Cell Transplantation

Seventy-four patients who relapsed after allogeneic stem cell transplantation were enrolled in a phase IIA study and treated with the sequential infusion of donor lymphocyte infusion (DLI) followed by cytokine-induced killer (CIK) cells. Seventy-three patients were available for the intention to treat analysis. At least 1 infusion of CIK cells was given to 59 patients, whereas 43 patients received the complete cell therapy planned (58%). Overall, 12 patients (16%) developed acute graft-versus-host disease (aGVHD) of grades I to II in 7 cases and grades III to IV in 5). In 8 of 12 cases, aGVHD developed during DLI treatment, leading to interruption of the cellular program in 3 patients, whereas in the remaining 5 cases aGVHD was controlled by steroids treatment, thus allowing the subsequent planned administration of CIK cells. Chronic GVHD (cGVHD) was observed in 11 patients (15%). A complete response was observed in 19 (26%), partial response in 3 (4%), stable disease in 8 (11%), early death in 2 (3%), and disease progression in 41 (56%). At 1 and 3 years, rates of progression-free survival were 31% and 29%, whereas rates of overall survival were 51% and 40%, respectively. By multivariate analysis, the type of relapse, the presence of cGVHD, and a short (<6 months) time from allogeneic hematopoietic stem cell transplantation to relapse were the significant predictors of survival. In conclusion, a low incidence of GVHD is observed after the sequential administration of DLI and CIK cells, and disease control can be achieved mostly after a cytogenetic or molecular relapse.

Eviction from the sanctuary: Development of targeted therapy against cell adhesion molecules in acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is a malignant hematological disease afflicting hematopoiesis in the bone marrow. While 80%-90% of patients diagnosed with ALL will achieve complete remission at some point during treatment, ALL is associated with high relapse rate, with a 5-year overall survival rate of 68%. The initial remission failure and the high rate of relapse can be attributed to intrinsic chemoprotective mechanisms that allow persistence of ALL cells despite therapy. These mechanisms are mediated, at least in part, through the engagement of cell adhesion molecules (CAMs) within the bone marrow microenvironment. This review assembles CAMs implicated in protection of leukemic cells from chemotherapy. Such studies are limited in ALL. Therefore, CAMs that are associated with poor outcomes or are overexpressed in ALL and have been shown to be involved in chemoprotection in other hematological cancers are also included. It is likely that these molecules play parallel roles in ALL because the CAMs identified to be a factor in ALL chemoresistance also work similarly in other hematological malignancies. We review the signaling mechanisms activated by the engagement of CAMs that provide protection from chemotherapy. Development of targeted therapies against CAMs could improve outcome and raise the overall cure rate in ALL.

TP53 in adult acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is characterized by a great biological and clinical heterogeneity. Despite most adult patients enter complete hematologic remission after induction therapy only 40% survive five or more years. Over the last 20 years, the definition of an accurate biologic leukemia profile and the minimal residual disease evaluation in addition to conventional risk criteria led to a significant improvement for the risk stratification. The alterations of the oncosuppressor gene TP53, including deletions, sequence mutations and defect in its expression due to regulatory defects, define a new important predictor of adverse outcome. More recently, new drugs have been developed with the aim of targeting p53 protein itself or its regulatory molecules, such as Mdm2, and restoring the pathway functionality. Therefore, TP53 alterations should be considered in the diagnostic work-up to identify high risk ALL patients in need of intensive treatment strategies or eligible for new innovative targeted therapies.

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

This study evaluated the safety, antitumor activity, pharmacokinetics, and pharmacodynamics of inotuzumab ozogamicin (InO) for CD22-positive relapsed/refractory acute lymphoblastic leukemia. In phase 1, patients received InO 1.2 (n = 3), 1.6 (n = 12), or 1.8 (n = 9) mg/m² per cycle on days 1, 8, and 15 over a 28-day cycle (≤6 cycles). The recommended phase 2 dose (RP2D) was confirmed (expansion cohort; n = 13); safety and activity of InO were assessed in patients receiving the RP2D in phase 2 (n = 35) and in all treated patients (n = 72). The RP2D was 1.8 mg/m² per cycle (0.8 mg/m² on day 1; 0.5 mg/m² on days 8 and 15), with reduction to 1.6 mg/m² per cycle after complete remission (CR) or CR with incomplete marrow recovery (CRi). Treatment-related toxicities were primarily cytopenias. Four patients experienced treatment-related venoocclusive disease/sinusoidal obstruction syndrome (VOD/SOS; 1 fatal). Two VOD/SOS events occurred during treatment without intervening transplant; of 24 patients proceeding to poststudy transplant, 2 experienced VOD/SOS after transplant. Forty-nine (68%) patients had CR/CRi, with 41 (84%) achieving minimal residual disease (MRD) negativity. Median progression-free survival was 3.9 (95% confidence interval, 2.9-5.4) months; median overall survival was 7.4 (5.7-9.2) months for all treated patients, with median 23.7 (range, 6.8-29.8) months of follow-up for all treated patients alive at data cutoff. Achievement of MRD negativity was associated with higher InO exposure. InO was well tolerated and demonstrated high single-agent activity and MRD-negativity rates. This trial was registered at www.clinicaltrials.gov as #NCT01363297.

Identification of a novel functional JAK1 S646P mutation in acute lymphoblastic leukemia

The survival rate of childhood acute lymphoblastic leukemia (ALL) is approaching 90%, while the prognosis of adults remains poor due to the limited therapeutic approaches. In order to identify new targets for ALL, we performed whole-exome sequencing on four adults with B-ALL and discovered a somatic JAK1 S646P mutation. Sanger sequencing of JAK1 was conducted on 53 ALL patients, and two cases exhibited A639G and P960S mutations separately. Functional studies demonstrated that only JAK1 S646P mutation could activate multiple signaling pathways, drive cytokine-independent cell growth, and promote proliferation of malignant cells in nude mice. Moreover, a high sensitivity to the JAK1/2 inhibitor ruxolitinib was observed in S646P mutant model. Exploration in a total of 209 ALL cases showed that JAK1 mutations occur at a frequency of 10.5% in T-ALL (2/19) and 1.6% in B-ALL (3/190). Collectively, our results suggested that JAK1 S646P is an activating mutation in vitro and in vivo. JAK-STAT pathway might represent a promising therapeutic target for ALL.

Managing CNS disease in adults with acute lymphoblastic leukemia

The central nervous system (CNS) is an important site of involvement by acute lymphoblastic leukemia (ALL) in adults. The prevalence is sufficiently high that prophylactic treatment is routinely given to this sanctuary site in order to eradicate occult disease that might otherwise lead to a relapse. A lumbar puncture should be routinely performed in all newly diagnosed patients with ALL. The risks of CNS leukemia vary by phenotype and genotype. Preventive treatment of the CNS during post-remission therapy has become an integral part of all current ALL treatment protocols. Most treatment regimens combine multiple doses of intrathecal chemotherapy with high-dose systemic methotrexate and/or cytarabine. Cranial irradiation is less commonly used for prophylaxis but is still the most effective treatment for overt CNS leukemia. Recurrences within the CNS usually coincide with or predict soon afterwards for systemic relapse in the marrow and blood.

Blinatumomab versus Chemotherapy for Advanced Acute Lymphoblastic Leukemia

BACKGROUND

Blinatumomab, a bispecific monoclonal antibody construct that enables CD3-positive T cells to recognize and eliminate CD19-positive acute lymphoblastic leukemia (ALL) blasts, was approved for use in patients with relapsed or refractory B-cell precursor ALL on the basis of single-group trials that showed efficacy and manageable toxic effects.

METHODS

In this multi-institutional phase 3 trial, we randomly assigned adults with heavily pretreated B-cell precursor ALL, in a 2:1 ratio, to receive either blinatumomab or standard-of-care chemotherapy. The primary end point was overall survival.

RESULTS

Of the 405 patients who were randomly assigned to receive blinatumomab (271 patients) or chemotherapy (134 patients), 376 patients received at least one dose. Overall survival was significantly longer in the blinatumomab group than in the chemotherapy group. The median overall survival was 7.7 months in the blinatumomab group and 4.0 months in the chemotherapy group (hazard ratio for death with blinatumomab vs. chemotherapy, 0.71; 95% confidence interval [CI], 0.55 to 0.93; P=0.01). Remission rates within 12 weeks after treatment initiation were significantly higher in the blinatumomab group than in the chemotherapy group, both with respect to complete remission with full hematologic recovery (34% vs. 16%, P<0.001) and with respect to complete remission with full, partial, or incomplete hematologic recovery (44% vs. 25%, P<0.001). Treatment with blinatumomab resulted in a higher rate of event-free survival than that with chemotherapy (6-month estimates, 31% vs. 12%; hazard ratio for an event of relapse after achieving a complete remission with full, partial, or incomplete hematologic recovery, or death, 0.55; 95% CI, 0.43 to 0.71; P<0.001), as well as a longer median duration of remission (7.3 vs. 4.6 months). A total of 24% of the patients in each treatment group underwent allogeneic stem-cell transplantation. Adverse events of grade 3 or higher were reported in 87% of the patients in the blinatumomab group and in 92% of the patients in the chemotherapy group.

CONCLUSIONS

Treatment with blinatumomab resulted in significantly longer overall survival than chemotherapy among adult patients with relapsed or refractory B-cell precursor ALL. (Funded by Amgen; TOWER ClinicalTrials.gov number, NCT02013167 .).

Significance of recurrence of minimal residual disease detected by multi-parameter flow cytometry in patients with acute lymphoblastic leukemia in morphological remission

We sought to determine the significance of minimal residual disease (MRD) relapse in patients with ALL after achieving MRD negative status following induction and consolidation therapy. Between January 2003 and September 2014, 647 newly diagnosed patients were treated [HyperCVAD-based (n = 531); Augmented BFM (n = 116)]. Six hundred and one (93%) achieved complete remission (CR), and 546 (91%) became MRD negative. Fifty-five patients [HyperCVAD-based (n = 49); Augmented BFM (n = 6)] developed recurrence of MRD while still in morphological CR and are the subjects of this study. MRD was assessed by 6-color (4-color prior to 2009) multi-parameter flow cytometry (MFC) at CR and multiple time points thereafter. Their median age was 44 years (range, 18-72 years), median WBC at initial presentation was 7.3 K/µL^-1 (range, 0.6-303.8 K/µL^-1 ) and median bone marrow blast percentage 88% (range, 26-98%). The median time to MRD relapse was 14 months (range 3-58 months). Forty-four (80%) patients subsequently developed morphological relapse after median of 3 months (range, <1-33 months) from detection of MRD recurrence. Treatments received after MRD positivity and prior to morphological relapse: 16 continued maintenance chemotherapy; 15 received late intensification; 9 allogeneic stem cell transplant, 9 changed chemotherapy, 6 no further therapy. Only six remain alive and in CR1 and nine are alive after morphological relapse. MRD relapse detected by MFC at any time after achieving CR is associated with a high risk for morphological relapse. SCT can result in long-term remission in some patients. Prospective studies of long-term MRD assessments, together with less toxic treatment strategies to eradicate MRD, are warranted.

Prognostic stratification improvement by integrating ID1/ID3/IGJ gene expression signature and immunophenotypic profile in adult patients with B-ALL

Background

Survival of adults with B-Acute Lymphoblastic Leukemia requires accurate risk stratification of patients in order to provide the appropriate therapy. Contemporary techniques, using clinical and cytogenetic variables are incomplete for prognosis prediction.

Methods

To improve the classification of adult patients diagnosed with B-ALL into prognosis groups, two strategies were examined and combined: the expression of the ID1/ID3/IGJ gene signature by RT-PCR and the immunophenotypic profile of 19 markers proposed in the EuroFlow protocol by Flow Cytometry in bone marrow samples.

Results

Both techniques were correlated to stratify patients into prognostic groups. An inverse relationship between survival and expression of the three-genes signature was observed and an immunophenotypic profile associated with clinical outcome was identified. Markers CD10 and CD20 were correlated with simultaneous overexpression of ID1, ID3 and IGJ. Patients with simultaneous expression of the poor prognosis gene signature and overexpression of CD10 or CD20, had worse Event Free Survival and Overall Survival than patients who had either the poor prognosis gene expression signature or only CD20 or CD10 overexpressed.

Conclusion

By utilizing the combined evaluation of these two immunophenotypic markers along with the poor prognosis gene expression signature, the risk stratification can be significantly strengthened. Further studies including a large number of patients are needed to confirm these findings.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-017-0506-4) contains supplementary material, which is available to authorized users.

Targeting BET proteins improves the therapeutic efficacy of BCL-2 inhibition in T-cell acute lymphoblastic leukemia

Inhibition of anti-apoptotic BCL-2 (B-cell lymphoma 2) has recently emerged as a promising new therapeutic strategy for the treatment of a variety of human cancers, including leukemia. Here, we used T-cell acute lymphoblastic leukemia (T-ALL) as a model system to identify novel synergistic drug combinations with the BH3 mimetic venetoclax (ABT-199). In vitro drug screening in primary leukemia specimens that were derived from patients with high risk of relapse or relapse and cell lines revealed synergistic activity between venetoclax and the BET (bromodomain and extraterminal) bromodomain inhibitor JQ1. Notably, this drug synergism was confirmed in vivo using T-ALL cell line and patient-derived xenograft models. Moreover, the therapeutic benefit of this drug combination might, at least in part, be mediated by an acute induction of the pro-apoptotic factor BCL2L11 and concomitant reduction of BCL-2 upon BET bromodomain inhibition, ultimately resulting in an enhanced binding of BIM (encoded by BCL2L11) to BCL-2. Altogether, our work provides a rationale to develop a new type of targeted combination therapy for selected subgroups of high-risk leukemia patients.

Inhibition of telomerase using BIBR1532 enhances doxorubicin-induced apoptosis in pre-B acute lymphoblastic leukemia cells

OBJECTIVES

Interest into targeting telomerase in cancer has increased by the recent disclosure that elevated telomerase activity is associated with disease recurrence and poor outcome in cancers. In addition, cellular acquisition of unlimited replicative potential, which is closely related to the maintenance of telomeres mostly via the reactivation of telomerase, has been shown to confer loss of sensitivity to a wide range of anti-neoplastic agents.

METHODS

To evaluate whether telomerase inhibition using non-nucleosidic inhibitor of telomerase BIBR1532 could enhance cytotoxic effect of doxorubicin in acute lymphoblastic leukemia, Nalm-6 pre-B ALL cells were subjected to combination treatment and subsequent cell viability, growth kinetics, caspase-3 activity, and transcriptional alteration of p73, p21, FOXO3a, c-Myc, hTERT, and other apoptosis-related target genes were investigated.

RESULTS

Combination of BIBR1532 with doxorubicin produced a synergistic anticancer effect probably through induction of p73. Transcription factor p73 not only suppressed the proliferative capacity of the cells through induction of p21-mediated G1 arrest, but also down-regulated the mRNA level of hTERT and c-Myc. Our results also report that BIBR1532 induced a caspase-dependent apoptosis, at least partially, through heightened ROS levels, and noteworthy enhanced the pro-oxidant property of doxorubicin. In harmony, transcriptional repression of survivin could be a probable underlying mechanism for the induction of apoptosis through shifting the ratio of death promoters to death repressors via alteration of Bax and Bcl2 expression.

CONCLUSIONS

Overall, it seems that combination of BIBR1532 and doxorubicin could be a novel therapeutic strategy for acute lymphoblastic leukemia that may be clinically accessible in the near future.

Effects of intensive induction and consolidation chemotherapy with idarubicin and high dose cytarabine on minimal residual disease levels in newly diagnosed adult precursor-B acute lymphoblastic leukemia

An intensive induction regimen, consisting of idarubicin and high dose cytarabine, was assessed in 19 adult patients, median age 44 years, with newly diagnosed precursor-B acute lymphoblastic leukemia (ALL). Patients achieving a complete response (CR) were given an attenuated consolidation course. The primary endpoints were induction death rate and incidence of serious non-hematological toxicity. Grades 3–4 diarrhoea occurred in 47% of patients during induction. Two patients (11%) died during induction therapy, and 2 were withdrawn due to resistant disease or prolonged marrow hypoplasia. Fifteen patients achieved CR (79%), but levels of minimal residual disease (MRD) after induction were comparable with those previously observed using a modified pediatric protocol. Overall survival at 5 years was 36.8% while leukemia-free survival was 44.1%. An intensive AML protocol used in adults with ALL resulted in substantial toxicity and provided similar levels of cytoreduction to conventional ALL protocols, without improving long-term outcomes.

Clinical significance of the ABCB1 and ABCG2 gene expression levels in acute lymphoblastic leukemia

OBJECTIVES

Acute lymphoblastic leukemia (ALL) is a clonal disease that accounts for 20% of acute leukemias in adults. A high percentage of adult patients (ranging from 70 to 80%) reach complete remission; however, the 5-year survival rate is only 20-40%. One of the main obstacles to treatment success is the drug resistance of leukemic cells. Therefore, our research group analyzed the ABCB1 and ABCG2 gene expression levels in 61 patients diagnosed with ALL and assessed whether the levels affected the clinical parameters and 40-month survival rate.

METHODS

The ABCB1 and ABCG2 gene expression levels were analyzed using real-time polymerase chain reaction in 61 patients diagnosed with ALL and 99 healthy donors as controls. The association between ABCB1 and ABCG2 gene expression levels and clinical variables was determined using the Chi-square test and Fisher's exact test. Overall survival (OS) was determined using the Kaplan-Meier method.

RESULTS

The results showed high ABCB1 and ABCG2 gene levels, which were 4.5 and 2.3 times the levels of healthy donors, respectively. A total of 52% of the study patients expressed high ABCB1 levels and were significantly associated with the high-risk patient group and a decreased 40-month survival rate of 78%. Only 49% of the patients expressed high ABCG2 gene levels. No association was found between the clinical parameters and the ABCG2 gene expression levels.

CONCLUSIONS

Early detection of ABCB1 gene expression levels could be important for the diagnosis and monitoring of ALL patients.

Treatment of older patients with acute lymphoblastic leukemia

The treatment of older patients with acute lymphoblastic leukemia (ALL) is an unmet medical need. With increasing age, ALL patients have a significantly lower clinical remission rate, higher early mortality, higher relapse rate, and poorer survival compared with younger patients. This is only partly explained by a higher incidence of poor prognostic factors in the older age group. Most importantly, intensive chemotherapy with or without stem cell transplantation (SCT) is less well tolerated in older patients. Some progress has been made with delivering age-adapted, moderately intensive chemotherapy protocols for Ph/BCR-ABL-negative ALL and combinations of tyrosine kinase inhibitors with chemotherapy in Ph/BCR-ABL-positive ALL. For the future, optimizing supportive care, introducing targeted therapies, novel immunotherapies, moderately intensified consolidation strategies, and reduced intensity SCT are promising approaches. Prospective clinical trials for older patients are urgently needed to test these approaches.

International reference analysis of outcomes in adults with B-precursor Ph-negative relapsed/refractory acute lymphoblastic leukemia

Adults with relapsed/refractory acute lymphoblastic leukemia have an unfavourable prognosis, which is influenced by disease and patient characteristics. To further evaluate these characteristics, a retrospective analysis of 1,706 adult patients with Ph-negative relapsed/refractory B-precursor acute lymphoblastic leukemia diagnosed between 1990-2013 was conducted using data reflecting the standard of care from 11 study groups and large centers in Europe and the United States. Outcomes included complete remission, overall survival, and realization of stem cell transplantation after salvage treatment. The overall complete remission rate after first salvage was 40%, ranging from 35%-41% across disease status categories (primary refractory, relapsed with or without prior transplant), and was lower after second (21%) and third or greater (11%) salvage. The overall complete remission rate was higher for patients diagnosed from 2005 onward (45%, 95% CI: 39%-50%). One- and three-year survival rates after first, second, and third or greater salvage were 26% and 11%, 18% and 6%, and 15% and 4%, respectively, and rates were 2%-5% higher among patients diagnosed from 2005. Prognostic factors included younger age, longer duration of first remission, and lower white blood cell counts at primary diagnosis. This large dataset can provide detailed reference outcomes for patients with relapsed/refractory Ph-negative B-precursor acute lymphoblastic leukemia. clinicaltrials.gov identifier: 02003612.

Hyper-CVAD Compared With BFM-like Chemotherapy for the Treatment of Adult Acute Lymphoblastic Leukemia. A Retrospective Single-Center Analysis

BACKGROUND

Several induction regimens have been developed for treatment of adult patients with acute lymphoblastic leukemia (ALL). However, only a few prospective randomized trials have directly compared these regimens.

PATIENTS AND METHODS

In this report, we retrospectively evaluated the outcome of 62 adult ALL patients treated with either hyper-CVAD (hyper fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone; n = 38) or a BFM (Berlin-Frankfurt-Munster)-like regimen (n = 24) between November 2000 and January 2016 at the American university of Beirut Medical Center in Lebanon. The feasibility of allogeneic stem cell transplantation (allo-SCT) for those patients was also evaluated.

RESULTS

The median follow-up time was 29 (range, 1-129) months. Fifteen (39%) and 10 (42%) patients underwent allo-SCT in the hyper-CVAD and BFM-like group, respectively. At the time of the last follow-up, 28 patients (74%) were in complete remission in the hyper-CVAD group versus 18 patients (75%) in the BFM-like group. Of those, 20 patients (53%) versus 11 patients (46%) were minimal residual disease-negative at the last follow-up, respectively. The 3-year overall survival rate (71.9% vs. 76.9%; P = .808) and 3-year disease-free survival (54.7% vs. 76.4%; P = .435) were similar in hyper-CVAD group compared with the BFM-like group, respectively. Both chemotherapies were relatively well tolerated.

CONCLUSION

Overall, despite the older age and a greater number of patients with high-risk category (including Philadelphia chromosome-positive) in the hyper-CVAD group, this did not translate into a difference in survival outcome between the 2 groups. The hyper-CVAD regimen appears to be feasible for adult patients with ALL in terms of tolerability and efficacy.

ERK/Drp1-dependent mitochondrial fission is involved in the MSC-induced drug resistance of T-cell acute lymphoblastic leukemia cells

The bone marrow microenvironment facilitates the proliferation and survival of leukemia cells, contributing to disease relapse. Bone marrow-derived mesenchymal stem cells (MSCs) are well known to promote cancer chemoresistance via soluble factors and cell adhesion. However, little is known about the effects of MSCs on the mitochondrial dynamics of T-cell acute lymphoblastic leukemia (T-ALL) cells, or how this may influence the chemoresistance of these cells. Here, we tested both indirect (Transwell) and direct coculture strategies, and found that MSCs protected T-ALL cells from chemotherapeutic cell death and cytotoxicity under both culture conditions. In addition, cell viability was higher in the direct contact system compared with the Transwell system. We further showed that exposure of T-ALL cells to MSCs decreased mitochondrial reactive oxygen species (ROS) levels and promoted a pro-glycolytic shift that was characterized by increased glucose uptake and lactate production with concomitant reductions in adenosine triphosphate production and mitochondrial membrane potential. In T-ALL cells cocultured with MSCs, the mitochondrial morphology of T-ALL cells were altered from elongation to fragmentation because of the extracellular signal-regulated kinase activation-mediated phosphorylation of the pro-fission factor, dynamin-related protein 1 (Drp1), at residue S616. Consistent with this, the expression of S616-phosphorylated Drp1 recapitulated the mitochondrial dynamics, mitochondrial ROS levels, metabolic switching and chemoresistance seen in T-ALL cells cocultured with MSCs. These findings suggest that the ability of MSCs to trigger Drp1 activation-induced changes in mitochondrial dynamics is crucial to their ability to protect cells against chemotherapeutic agents.

Harnessing T cells to fight cancer with BiTE® antibody constructs--past developments and future directions

Bispecific T-cell engager (BiTE(®)) antibody constructs represent a novel immunotherapy that bridges cytotoxic T cells to tumor cells, thereby inducing target cell-dependent polyclonal T-cell activation and proliferation, and leading to apoptosis of bound tumor cells. Anti-CD19 BiTE(®) blinatumomab has demonstrated clinical activity in Philadelphia chromosome (Ph)-negative relapsed or refractory (r/r) acute lymphoblastic leukemia (ALL) eventually resulting in conditional approval by the U.S. Food and Drug Administration in 2014. This drug is currently further developed in pediatric and Ph(+) r/r, as well as in minimal residual disease-positive ALL, and might also offer clinical benefit for patients with non-Hodgkin's lymphoma, especially for those with aggressive forms like diffuse large B-cell lymphoma. Another BiTE(®) antibody construct in hemato-oncology designated AMG 330 targets CD33 on acute myeloid leukemia blast cells. After showing promising ex vivo activity, this drug candidate has recently entered phase 1 clinical development, and has further indicated potential for combination with checkpoint inhibitors. In solid tumor indications, three BiTE(®) antibody constructs have been tested in phase 1 studies so far: anti-EpCAM BiTE(®) AMG 110, anti-CEA BiTE(®) MEDI-565/AMG 211, and anti-PSMA BiTE(®) BAY2010112/AMG 212. Pertinent questions comprise how to maximize BiTE(®) penetration and T-cell infiltration of the tumor while simultaneously minimizing any adverse events, which is currently explored by a continuous intravenous infusion approach. Thus, BiTE(®) antibody constructs will hopefully provide new treatment options for patients in several indications with high unmet medical need.