Treatment of acute myeloid leukemia in older patients

PRL2 phosphatase enhances oncogenic FLT3 signaling via dephosphorylation of the E3 ubiquitin ligase CBL at tyrosine 371

Acute myeloid leukemia (AML) is an aggressive blood cancer with poor prognosis. FMS-like tyrosine kinase receptor-3 (FLT3) is one of the major oncogenic receptor tyrosine kinases aberrantly activated in AML. Although protein tyrosine phosphatase PRL2 is highly expressed in some subtypes of AML compared with normal human hematopoietic stem and progenitor cells, the mechanisms by which PRL2 promotes leukemogenesis are largely unknown. We discovered that genetic and pharmacological inhibition of PRL2 significantly reduce the burden of FLT3-internal tandem duplications-driven leukemia and extend the survival of leukemic mice. Furthermore, we found that PRL2 enhances oncogenic FLT3 signaling in leukemia cells, promoting their proliferation and survival. Mechanistically, PRL2 dephosphorylates the E3 ubiquitin ligase CBL at tyrosine 371 and attenuates CBL-mediated ubiquitination and degradation of FLT3, leading to enhanced FLT3 signaling in leukemia cells. Thus, our study reveals that PRL2 enhances oncogenic FLT3 signaling in leukemia cells through dephosphorylation of CBL and will likely establish PRL2 as a novel druggable target for AML.

Allogeneic TCRαβ deficient CAR T-cells targeting CD123 in acute myeloid leukemia

Acute myeloid leukemia (AML) is a disease with high incidence of relapse that is originated and maintained from leukemia stem cells (LSCs). Hematopoietic stem cells can be distinguished from LSCs by an array of cell surface antigens such as CD123, thus a candidate to eliminate LSCs using a variety of approaches, including CAR T cells. Here, we evaluate the potential of allogeneic gene-edited CAR T cells targeting CD123 to eliminate LSCs (UCART123). UCART123 cells are TCRαβneg T cells generated from healthy donors using TALEN® gene-editing technology, decreasing the likelihood of graft vs host disease. As safety feature, cells express RQR8 to allow elimination with Rituximab. UCART123 effectively eliminates AML cells in vitro and in vivo with significant benefits in overall survival of AML-patient derived xenograft mice. Furthermore, UCART123 preferentially target AML over normal cells with modest toxicity to normal hematopoietic stem/progenitor cells. Together these results suggest that UCART123 represents an off-the shelf therapeutic approach for AML.

CD123, the interleukin-3 receptor alpha chain, is aberrantly expressed in acute myeloid leukemia blasts and leukemia stem cells. Here the authors report the design and characterize the anti-tumor activity of allogeneic CD123-targeted CAR-T cells as a therapeutic approach for acute myeloid leukemia.

Efficacy and Safety of Metronomic Chemotherapy Versus Palliative Hydroxyurea in Unfit Acute Myeloid Leukemia Patients: A Multicenter, Open-Label Randomized Controlled Trial

Background:

Management of unfit AML patients is a therapeutic challenge. Most hematologists tend to avoid aggressive treatment leaving patients with a choice of best supportive care. We hypothesized that metronomic chemotherapy could be an alternative treatment for unfit AML patients.

Methods:

A multi-center randomized controlled trial was conducted in seven university-affiliated hospitals in Thailand. Unfit AML patients were recruited and followed up from December 2014 to December 2017. Patients were randomly assigned to receive either metronomic chemotherapy or palliative hydroxyurea. Overall survival rates were compared using Cox’s proportional hazard survival analysis.

Results:

A total of 81 eligible patients were randomly allocated and included for ITT analysis. The OS rate was higher in group receiving metronomic chemotherapy than in group receiving palliative treatment at 6 and 12 months with borderline significance (6 months HR 0.60; 95%CI 0.36, 1.02; p-value 0.060; 12 months: HR 0.66; 95%CI 0.41, 1.08; p-value 0.097).

Conclusion:

Metronomic chemotherapy could prolong survival time of unfit AML patients, especially in the first 12 months after diagnosis without increasing treatment-associated adverse events.

Phosphatase of regenerating liver in hematopoietic stem cells and hematological malignancies

The phosphatases of regenerating liver (PRLs), consisting PRL1, PRL2 and PRL3, are dual-specificity protein phosphatases that have been implicated as biomarkers and therapeutic targets in several solid tumors. However, their roles in hematological malignancies are largely unknown. Recent findings demonstrate that PRL2 is important for hematopoietic stem cell self-renewal and proliferation. In addition, both PRL2 and PRL3 are highly expressed in some hematological malignancies, including acute myeloid leukemia (AML), chronic myeloid leukemia (CML), multiple myeloma (MM) and acute lymphoblastic leukemia (ALL). Moreover, PRL deficiency impairs the proliferation and survival of leukemia cells through regulating oncogenic signaling pathways. While PRLs are potential novel therapeutic targets in hematological malignancies, their exact biological function and cellular substrates remain unclear. This review will discuss how PRLs regulate hematopoietic stem cell behavior, what signaling pathways are regulated by PRLs, and how to target PRLs in hematological malignancies. An improved understanding of how PRLs function and how they are regulated may facilitate the development of PRL inhibitors that are effective in cancer treatment.

Extramedullary relapse of the AML transformed from MDS following auto-HSCT: a case report

The treatment for AML (Acute myeloid/myelogenous leukemia) transformed from MDS (myelodysplastic syndrome) is difficult and controversial clinically, especially in elder patients. In this case report, we diagnosed a 59-year-old female patient with AML-M2a transformed form MDS which might be caused by her chemotherapy for mastocarcinoma. After achieving complete remission (CR) through combined chemotherapy, autologous peripheral blood stem cell transplantation (auto-PBSCT) was attempted. Following auto-HSCT, marrow showed continuous CR but the patient later developed extramedullary bone-infiltration relapse. Then local radiotherapy has been applied, and the patient now has prolonged survival. This is the first (or a successful) case report of auto-HSCT in an elderly patient with AML transformed from MDS.

Mimic of manganese superoxide dismutase induces apoptosis in human acute myeloid leukemia cells

Abstract Increasing manganese superoxide dismutase (MnSOD) expression can suppress the malignant phenotype in various cancer cell lines and suppress tumor formation in xenograft and transgenic mouse models. A mimic of manganese superoxide dismutase (MnSODm), synthesized by a chemical method, has been shown to possess antitumor properties. However, the anticancer activity of MnSODm in acute myeloid leukemia (AML) is still obscure. In this study, we investigated the effects of MnSODm on the apoptosis of human leukemia HL-60 cells. Results showed that MnSODm significantly reduced the proliferation of HL-60 cells in a concentration- and time-dependent manner. By flow cytometric analysis, we found that MnSODm treatment resulted in increased apoptosis in HL-60 cells. Further analysis demonstrated involvement of activation of the caspase cascade, cleavage of poly(ADP-ribose) polymerase (PARP) and release of cytochrome c in MnSODm-induced apoptosis. The results also showed that the expression of anti-apoptotic Bcl-2 and Bid were dose-dependently decreased, whereas the expression of pro-apoptotic Bax protein was increased. Thus, MnSODm induced apoptosis in HL-60 cells via mitochondria-mediated, caspase-dependent pathways. MnSODm inhibition of Akt phosphorylation may contribute to MnSODm-mediated acute myeloid leukemia cell growth inhibition and apoptosis induction.

Clinical symptoms and chemotherapy completion in elderly patients with newly diagnosed acute leukemia: a retrospective comparison study with a younger cohort

Background

Cancer affects older adults disproportionately. The disease is often difficult to diagnose and treat due to co-morbidities and performance status, and patients tend to discontinue chemotherapy prematurely. There are no systemic studies of the reasons and factors that create a higher withdrawal rate in older acute leukemia patients. This study tried to understand the initial characteristics, blood counts and bone marrow measurements in older acute leukemia patients by comparing them with a younger group to provide information and assistance in early clinical diagnosis, treatment and reasons for treatment withdrawal.

Methods

Using retrospective medical record reviews, we examined clinical characteristics and chemotherapy completion status in the patients of two groups (age ≥ 60, n = 183 and age <60, n = 183) who were diagnosed with acute leukemia for the first time and were hospitalized in Union Hospital Affiliated with Fujian Medical University from 2004 to 2008.

Results

There were no statistical differences in initial presenting symptoms of fatigue (67.2% vs. 57.9%, P>0.05) and pallor (53% vs. 59.6%, P>0.05) between the two groups, but older patients demonstrated more underlying diseases including lung infections (25.7%, P = <0.001), cardiovascular disease (4.4%, P = 0.007), and hypertension (20.8%, P =< 0.001). The complete remission rate after chemotherapy (1 to 2 courses) was 49.5% in the older group and 66.7% in the younger group (χ² = 6.202, P = 0.013). The percentage of patients age 60 and older who prematurely discontinued chemotherapy (50.3%), mainly due to the influences of traditional Chinese concept of critical illness, financial difficulties, and intolerance to adverse reactions to chemotherapy, was significantly higher than that of younger patients (37.7%) (χ² = 5.866, P = 0.015).

Conclusions

A comprehensive approach to diagnosis, treatment selection, and toxicity management, and implementing strategies to enhance treatment compliance may improve outcomes in older adults with acute leukemia.

Acute myeloid leukaemia in the elderly: a review

The majority of patients with acute myeloid leukaemia (AML) are elderly. Advancements in supportive care and regimen intensification have resulted in improvements in clinical outcomes for younger AML patients, but analogous improvements in older patients have not been realized. While outcomes are compromised by increased comorbidities and susceptibility to toxicity from therapy, it is now recognized that elderly AML represents a biologically distinct disease that is more aggressive and less responsive to therapy. Some patients tolerate and benefit from intensive remission-induction approaches, while others are best managed with less aggressive strategies. The challenge is to differentiate these groups based on host-related and biological features, in order to maximize the therapeutic benefit and minimize toxicity. As more is understood about the complicated pathogenesis and molecular basis of AML, there are more opportunities to develop and test targeted therapies. Elderly patients, with their narrow therapeutic window, are well positioned to derive a benefit from these novel agents, and therefore, despite a difficult past, there are reasons to be optimistic about the future of elderly AML.

Acute myeloid leukemia stem cells: seek and destroy

Most adult patients with acute myeloid leukemia (AML) die from their disease. Relapses are frequent even after aggressive multiagent chemotherapy and allogeneic stem cell transplantation. AML is a biologically heterogeneous disease, characterized by frequent cytogenetic abnormalities and an increasing spectrum of genetic mutations and molecular aberrations. Laboratory data suggest that AML originates from a rare population of cells, termed leukemic stem cells (LSCs) or leukemia-initiating cells, which are capable of self-renewal, proliferation and differentiation. These cells may persist after treatment and are probably responsible for disease relapse. This review will describe bench and translational research in LSCs and discuss how the data should be used to change the direction of developmental therapeutics and clinical trials in AML.

Haplophytin-A induces caspase-8-mediated apoptosis via the formation of death-inducing signaling complex in human promyelocytic leukemia HL-60 cells

Haplophytin-A (10-methoxy-2,2-dimethyl-2,6-dihydro-pyrano[3,2-c]quinolin-5-one), a novel quinoline alkaloid, was isolated from the Haplophyllum acutifolium. In this study, we investigated the effect of haplophytin-A on the apoptotic activity and the molecular mechanism of action in human promyelocytic leukemia HL-60 cells. Treatment with haplophytin-A (50μM) induced classical features of apoptosis, such as, DNA fragmentation, DNA ladder formation, and the externalization of annexin-V-targeted phosphatidylserine residues in HL-60 cells. In addition, haplophytin-A triggered the activations of caspase-8, -9, and -3, and the cleavage of poly (ADP-ribose) polymerase (PARP) in HL-60 cells. In addition, haplophytin-A caused the loss of mitochondrial membrane potential (ΔΨ(m)) and the release of cytochrome c and Smac/DIABLO to the cytosol, and modulated the expression levels of Bcl-2 family proteins. We further demonstrated that knockdown of caspase-8 using its siRNA inhibited the mitochondrial translocation of tBid, the activations of caspase-9 and caspase-3, and subsequent DNA fragmentation by haplophytin-A. Furthermore, haplophytin-A-induced the formation of death-inducing signaling complex (DISC) and then activated caspase-8 in HL-60 cells. During haplophytin-A-induced apoptosis, caspase-8-stimulated tBid provide a link between the death receptor-mediated extrinsic pathway and the mitochondria- mediated intrinsic pathway. Taken together, these results suggest that the novel compound haplophytin-A play therapeutical role for leukemia via the potent apoptotic activity through the extrinsic pathway, involving the intrinsic pathway.

Levels of care: defining best supportive care in elderly patients with acute myeloid leukemia

This article reviews published data on best supportive care (BSC) in older patients with acute myeloid leukemia (AML) and proposes improvements in defining this critical aspect of treatment. A clinical challenge is to prospectively identify patients who could benefit from existing therapies and to optimize their treatment tolerance by improving BSC. Advanced age and poor performance status consistently emerge as reliable indicators of poor outcome in older AML patients and have historically been the most important variables used to stratify treatment. Performance status is notoriously difficult to assess, and a "snapshot" view at the time of initial presentation can be misleading. Comorbidity scales may be a better predictor of outcome, but studies looking at their effectiveness are variable. New methods are needed to stratify patients. Although the prognosis of older AML patients is generally dismal, selected patients benefit from treatment and can have prolonged survival. Because it has never been shown that BSC as a sole therapeutic approach is kinder, less expensive, or better for older AML patients, it should be reserved for select clinical situations.

Sequence of administration and methylation of SOCS3 may govern response to gemtuzumab ozogamicin in combination with conventional chemotherapy in patients with refractory or relapsed acute myelogenous leukemia (AML)

In older patients suffering from acute myelogenous leukemia (AML), aggressive chemotherapy is accompanied with high treatment-related morbidity and mortality. Gemtuzumab ozogamicin (GO), a humanized monoclonal anti-CD33 antibody, represents a well tolerated treatment option, but optimal treatment schedules are still unknown. Additionally, Suppressor of cytokine signaling 3 (SOCS3) inhibits the CD33-induced block on cytokine-induced proliferation. Consequently, a variable response of AML cells to anti-CD33-targeted therapy may be caused by modulation of SOCS3 expression. Twenty-four patients with refractory or relapsed CD33-positive AML received GO as a single agent before or after conventional chemotherapy. The methylation status of the SOCS3 CpG island was assessed by methylation-specific polymerase chain reaction. Response (RR) and overall survival (OS) were significantly higher in 16 patients receiving chemotherapy before GO (RR 81%, OS 14.8 months) compared to three patients who received GO single agent therapy (RR 33%, OS 7.2 months) or 16 with GO before chemotherapy (RR 0% OS 2.2 months, P = 0.01 for RR and P < 0.001 for OS). Methylation of the SOCS3 CpG island was found in 8/24 patients. There was a trend towards a higher RR and longer OS in patients with SOCS3 hypermethylation (RR 86%, OS 25.1 months) compared to unmethylated SOCS3 (RR 56%, OS 10.3 months, P = 0.09). Administration of GO a few days after chemotherapy seems to provide better response and survival compared to administration of GO directly before chemotherapy. The potential role of SOCS3 hypermethylation as a biomarker should be further investigated in patients undergoing GO containing therapies.

Phase II study of clofarabine monotherapy in previously untreated older adults with acute myeloid leukemia and unfavorable prognostic factors

PURPOSE

This phase II study assessed clofarabine monotherapy in older adults (>or= 60 years of age) with untreated acute myeloid leukemia (AML) and at least one unfavorable baseline prognostic factor.

PATIENTS AND METHODS

Clofarabine was administered intravenously for 5 days at 30 mg/m(2)/d during induction and 20 mg/m(2)/d during reinduction/consolidation (six cycles maximum). The primary end point was overall remission rate (ORR; ie, complete remission [CR] plus CR with incomplete platelet recovery [CRp]).

RESULTS

In 112 evaluable patients who were treated (median age, 71 years; range, 60 to 88 years), the ORR was 46% (38% CR, 8% CRp). ORR by unfavorable prognostic factor was 39% for patients >or= 70 years of age; 32% for Eastern Cooperative Oncology Group (ECOG) performance status 2; 51% for antecedent hematologic disorder; 54% for intermediate karyotype; 42% for unfavorable karyotype; and 48%, 51%, and 38% for one, two, and three risk factors, respectively. The median disease-free survival was 37 weeks (95% CI, 26 to 56 weeks). Median duration of remission was 56 weeks (95% CI, 33 to not estimable). The estimated median overall survival was 41 weeks (95% CI, 28 to 53 weeks) for all patients, 59 weeks for patients with CR/CRp, and 72 weeks for patients with CR. The 30-day all-cause mortality was 9.8%. The most common non-laboratory drug-related toxicities (>or= 20% patients) were nausea, febrile neutropenia, vomiting, diarrhea, rash, and fatigue.

CONCLUSION

Clofarabine is an active agent with acceptable toxicity in patients age 60 years or older with untreated AML who have at least one unfavorable prognostic factor. ORR did not seem affected by the presence of multiple unfavorable prognostic factors.

Treating octogenarian and nonagenarian acute myeloid leukemia patients--predictive prognostic models

BACKGROUND

Treating the octogenarian and nonagenarian patients who have acute myeloid leukemia (AML) with intensive chemotherapy is controversial. Several models to predict outcome were proposed, including the use of a comorbidity index. However, it is unclear whether the Charlson comorbidity index (CCI) or the hematopoietic cell transplant comorbidity index (HCTCI) is more sensitive.

METHODS

The authors analyzed their experience with 92 patients aged >or=80 years who had AML. Patients' pretreatment characteristics and their treatment outcomes were recorded.

RESULTS

All patients were offered intensive treatment; 59 patients (64%) were treated intensively with a variety of regimens, whereas 33 patients (36%) elected to receive supportive care. The CCI and the HCTCI had similar predictive ability for outcome in both groups. A multivariate analyses of prognostic factors identified near-normal albumin (48% of patients; 1-year survival rate, >27%) as a favorable factor for the whole cohort, age <83 years (47% of patients; 1-year survival rate, >25%) and nonmonocytic morphology (75% of patients; 1-year survival rate, >26%) as favorable factors for the intensively treated cohort, and bone marrow blasts <46% (50% of patients; 1-year survival rate, >19%) as a favorable factor for patients who received supportive care.

CONCLUSIONS

This retrospective analysis was developed to assist in treatment decisions for octogenarian and nonagenarian patients with AML. The findings will need validation in a prospective study.

Arsenic trioxide and low-dose cytarabine in older patients with untreated acute myeloid leukemia, excluding acute promyelocytic leukemia

BACKGROUND

Acute myeloid leukemia (AML) carries a dismal prognosis in older patients. In this study, the authors evaluated the safety and efficacy of arsenic trioxide combined with low-dose cytarabine in untreated patients aged >or=60 years with AML.

METHODS

In a phase 1/2 design, arsenic trioxide was administered intravenously at a dose of 0.25 mg/kg on Days 1 through 5 and on Days 8 through 12, and low-dose cytarabine was given subcutaneously twice daily on Days 1 through 14 in escalating doses to a target of 10 mg/m(2) per dose. Of 64 patients who had pathologically confirmed AML, excluding patients with acute promyelocytic leukemia and using World Health Organization criteria, the median age was 71 years, 10 patients (16%) had treatment-related AML, 40 patients (63%) had an antecedent myelodysplastic syndrome or myeloproliferative disorder, and 35 patients (55%) had unfavorable cytogenetics. Thirty-four patients (53%) had an Eastern Cooperative Oncology Group performance status of 2 or 3.

RESULTS

Complete remission was achieved in 21 of 61 patients (34%), including 15 of 50 patients (30%) who had secondary or treatment-related AML, 10 of 33 patients (30%) who had unfavorable cytogenetics, and 6 of 34 patients (18%) who had a poor baseline performance status. The mortality rate within the first 4 weeks was 8%. Neutropenic fever was observed in >80% of patients, and 41% of patients had bacteremia. Nonhematologic toxicity generally was mild and reversible and included fatigue, nausea, diarrhea, rash, peripheral edema, and elevated transaminases. There were no clinically significant cardiac arrhythmias.

CONCLUSIONS

The addition of arsenic trioxide to low-dose cytarabine appeared to improve responses in elderly patients who had AML compared with either agent alone, and a randomized trial of the combination versus single-agent low-dose cytarabine is ongoing.

Tannic acid-induced apoptosis and -enhanced sensitivity to arsenic trioxide in human leukemia HL-60 cells

Tannic acid (TA), a glucoside of gallic acid polymer, has been shown to possess anti-bacterial, anti-enzymatic, anti-tumor and astringent properties. However, the anti-cancer activity of TA in leukemia is still obscure. In this study, we showed TA-induced apoptotic death in acute myeloid leukemia (AML) HL-60 cells via dose- and time-dependent manner as well as increase of sub-G1 fraction, chromosome condensation, and DNA fragmentation. Further analysis demonstrated the involvement of activation of caspase cascade, cleavage of poly (ADP-ribose) polymerase (PARP), disruption of mitochondrial membrane potential, and release of Cytochrome C, in TA-induced apoptosis. These effects were probably associated with the increase of intracellular superoxide in mitochondrial signaling pathway which attributed to the down-regulation of superoxide dismutase (SOD). Notably, a low dose of TA is sufficient to aggravate arsenic trioxide (As(2)O(3))-induced cytotoxicity in HL-60 cells. Altogether, this study suggested the effects of TA to induce apoptosis in HL-60 and therapeutic potential in AML by being an adjunct to As(2)O(3).