Relevance of pathologic classifications and diagnosis of acute myeloid leukemia to clinical trials and clinical practice

Outcomes and challenges treating pediatric acute myeloid leukemia: a retrospective analysis of patients treated at the Fundación Valle del Lili between 2011 and 2020

INTRODUCTION

Acute myeloid leukemia is a challenging disease, due to a poor prognosis in developing countries. Herein, we aim to describe the clinical characteristics and outcomes after chemotherapy and transplantation.

METHODS

A retrospective analytic observational study was performed with patients under 18 years of age with newly diagnosed acute myeloid leukemia treated at a referral center in Colombia. Two groups were compared: induction therapy (IT) and induction therapy plus consolidation (IT + C). The survival analysis was performed using the Kaplan-Meier method.

RESULTS

We analyzed 34 patients diagnosed with acute myeloid leukemia; 20 received hematopoietic stem cell transplantation. Most were French-American-British (FAB) classification types M1, M5 and M0. The transplantation was haploidentical in 65%, conditioning was myeloablative in 67% and graft-versus-host disease prophylaxis was performed with post-transplant cyclophosphamide in 70%. Overall, the 5-year survival was 52% and the overall 5-year survival in the transplanted group was 80%. There were 16 deaths; in the IT group, n = 12, and in the IT + C group, n = 4. In the former, the main cause of death was septic shock and in the latter, it was relapse.

CONCLUSION

Transplantation is a safe option. Receiving treatment and supportive measures in hematopoietic stem cell transplantation units is necessary to avoid infections, especially during induction cycles.

Prognosis of Acute Myeloid Leukemia in the General Population: Data from Southern Switzerland

Aims and background

To evaluate the outcome of adult patients with de novo acute myeloid leukemia in the Italian-speaking part of Switzerland and to identify prognostic factors, time to progression and overall survival.

Methods and study design

Data of all adult patients diagnosed with acute myeloid leukemia from January 1984 to December 2003 were collected retrospectively. Univariate and multivariate analysis for time to progression and overall survival were performed.

Results

The incidence of acute myeloid leukemia in the adult population in southern Switzerland is 2.6/100,000 per year. Complete clinical and pathological data and follow-up information were available for 128 patients. The median age was 67 years (range, 18 to 94). The median follow-up was 97 months. Median overall survival was 6 months, with a 2-year overall survival of 16%. Median time to progression was 3 months. Thirty-five patients (median age, 80 years) were given best supportive care and/or palliative chemotherapy. The median survival in this subset was 2 months. Of the 93 patients treated with a curative intent, 48 were older than 60 years. The complete remission rate after induction chemotherapy was 80% for patients younger than 60 years and 31% for those older than 60 years (P <0.0001). Overall survival at 2 years was 40% and 12%, respectively (P <0.0005). The relapse rate was 61%, and only 28% of the patients who were given reinduction chemotherapy reached a second complete remission. Of the patients treated with curative intent, 52% were treated in a clinical trial. Their median age was significantly lower than those not included in a trial: 57 vs 66 years (P <00001). Patients treated in a trial had a significantly better prognosis than those not so treated (median survival, 12 vs 6 months). Patients treated with high-dose cytarabine as first-line therapy (given to 25 of 93 patients treated with a curative intent) had a better survival than those given standard cytarabine doses (P <0.0005). The outcome of the patients treated after 1993 was significantly better (P = 0.026) than that of the previously treated cohort. In multivariate analysis (not including cytogenetic data), only age (P = 0.005), performance status >1 (P = 0.001) and treatment given before/after 1993 (P = 0.044) were found to be independent prognostic factors for both overall survival and time to progression.

Conclusions

Most patients with acute myeloid leukemia are older than 60 years, and their outcome is still disappointing. For younger patients, the prognosis is better if they receive high-dose cytarabine as post-remission therapy and if they are treated in the setting of a clinical trial.

Telomerase reverse transcriptase (TERT) A1062T mutation as a prognostic factor in Egyptian patients with acute myeloid leukemia (AML)

This study aimed to evaluate the incidence and clinical and prognostic impact of TERT A1062T mutation in AML patients treated at Mansoura Oncology Center. Screening for TERT A1062T mutation in exon 15 of the TERT gene was performed on diagnostic DNA samples from 153 AML patients and 197 healthy subjects as a control group by using sequence-specific primers. TERT A1062T mutation was detected in 18 cases out of 153 patients (11.8 %) and in one out of 197 control group subjects (0.51 %). The achievement of complete remission was significantly higher in AML group with wild type as compared to that in the mutant one (53.3 vs 16.7 %, respectively). In addition, the relapse rate was significantly higher in the mutant patients as compared to those with wild type (62.5 vs 28.2 %, respectively). The AML patients with TERT (A1062T) mutation had shorter overall survival than patients with wild type (P = 0.001). In a multivariable analysis, TERT (A1062T) mutational status is independently worse predictor factor (P = 0.007) when controlling for cytogenetic status (P = <0.001), performance status (P = <0.001) and bone marrow blast cells (P = 0.001). In conclusion, TERT A1062T mutation is an independent negative prognostic factor in AML patients. Therefore, molecular testing for TERT A1062T mutation in patients with AML is recommended in order to delineate their prognostic status.

Expression of immune inhibitory receptor ILT3 in acute myeloid leukemia with monocytic differentiation

BACKGROUND

The diagnosis of AML with monocytic differentiation is limited by the lack of highly sensitive and specific monocytic markers. Immunoglobulin-like transcript 3 (ILT3) is an immune inhibitory receptor expressed by myelomonocytic cells and at high levels by tolerogenic dendritic cells.

METHODS

Using flow cytometry, we analyzed the expression of ILT3 in 37 patients with AML and 20 patients with no detectable disease.

RESULTS

We showed that ILT3 was expressed in all cases of AML displaying monocytic differentiation (FAB M4/M5; N = 18), but not in AML M1/M2 and M3 (N = 19; P < 0.0001). Co-expression of ILT3 and immature cell markers, such as CD34 and CD117, was observed in monoblastic leukemia. ILT3 expression was preserved after treatment in M4/M5 patients with refractory or relapsed disease. ILT3 expression was associated with the presence of cytogenetic abnormalities linked to an intermediate prognosis (P = 0.001). Rare CD45dimCD34+CD117+ILT3+ cells were identified in noninvolved bone marrow, suggesting that ILT3 expression is acquired at an early stage by normal myelomonocytic precursors.

CONCLUSIONS

ILT3 is a highly sensitive and specific marker which distinguishes AML with monocytic differentiation from other types of AML. Testing of ILT3 expression should be incorporated into the initial diagnostic work-up and monitoring of patients with AML.

Elevated calpain activity in acute myelogenous leukemia correlates with decreased calpastatin expression

Calpains are intracellular cysteine proteases that have crucial roles in many physiological and pathological processes. Elevated calpain activity has been associated with many pathological states. Calpain inhibition can be protective or lethal depending on the context. Previous work has shown that c-myc transformation regulates calpain activity by suppressing calpastatin, the endogenous negative regulator of calpain. Here, we have investigated calpain activity in primary acute myelogenous leukemia (AML) blast cells. Calpain activity was heterogeneous and greatly elevated over a wide range in AML blast cells, with no correlation to FAB classification. Activity was particularly elevated in the CD34+CD38− enriched fraction compared with the CD34+CD38+ fraction. Treatment of the cells with the specific calpain inhibitor, PD150606, induced significant apoptosis in AML blast cells but not in normal equivalent cells. Sensitivity to calpain inhibition correlated with calpain activity and preferentially targeted CD34+CD38− cells. There was no correlation between calpain activity and p-ERK levels, suggesting the ras pathway may not be a major contributor to calpain activity in AML. A significant negative correlation existed between calpain activity and calpastatin, suggesting calpastatin is the major regulator of activity in these cells. Analysis of previously published microarray data from a variety of AML patients demonstrated a significant negative correlation between calpastatin and c-myc expression. Patients who achieved a complete remission had significantly lower calpain activity than those who had no response to treatment. Taken together, these results demonstrate elevated calpain activity in AML, anti-leukemic activity of calpain inhibition and prognostic potential of calpain activity measurement.

New agents for the treatment of acute myeloid leukemia

The heterogeneity of acute myeloid leukemia (AML) has been established by many new insights into the diagnosis, pathogenesis, clinical manifestations, treatment, and prognosis of patients with AML. Morphology remains the foundation for the diagnosis. However, additional diagnostic studies, including immunophenotyping, cytogenetic evaluation, and molecular genetic studies, are necessary to develop treatments because specific subtypes of AML can now be approached with targeted therapy. Acute promyelocytic leukemia (APL), defined by a single molecular abnormality, is now treated with specific targeted therapy, all-trans retinoic acid (ATRA), and this subtype of AML is now highly curable. Currently, a number of agents have been explored in AML, including anti-CD33 antibodies and immunoconjugate drugs, inhibitors of multidrug resistance proteins, farnesyl transferase inhibitors, tyrosine kinase inhibitors, anti-Bcl-2 transcription agents, and inhibitors of mammalian target of rapamycin (mTOR). New alkylating agents, and purine analogs such as Cloretazine and clofarabine, affect DNA and ribonucleoside reductases, respectively. These agents have shown promise in small studies. Large phase III studies will address whether these are effective in inducing complete responses. Combining targeted agents with chemotherapy may improve the response rates. The plan for the future is to find therapeutic strategies that are specific for patients based on the specific biology of the disease. Future studies will investigate combinations of targeted therapies with each other and with chemotherapies to maximize the inhibition of multiple pathways present in AML. Additionally, evaluation of the identified prognostic factors and gene mutations will enable further pathologic classification of patients with AML.

Modeling the Pharmacodynamics of Highly Schedule-Dependent Agents: Exemplified by Cytarabine-Based Regimens in Acute Myeloid Leukemia

BACKGROUND

Many agents in antineoplastic chemotherapy are highly schedule dependent. Therefore, variables such as total dose and also the area under the curve (AUC) that are schedule insensitive are generally insufficient to adequately represent treatment strength.

PURPOSE

To establish a descriptor of treatment strength that takes into account the differential contribution of plasma concentrations (C) and exposure times (T) towards the cytotoxic effect and to investigate whether such a pharmacodynamically weighed descriptor is better correlated to the clinical effect than conventional variables.

PATIENTS AND METHODS

The paradigm "C(N) x T = constant" (for an isoeffect) incorporates a weighing factor N (concentration coefficient) into the conventional description of the AUC that quantitates the differential contribution of C and T towards the cytotoxic effect. N was to be numerically derived from a multitude of in vitro isoeffect analyses of the major agents in acute myeloid leukemia (AML) therapy from patient samples (n = 57).

RESULTS

For cytarabine, N was 0.45, numerically expressing the substantially higher relevance of T versus C for its cytotoxic effect. In a meta-analysis of 49 study arms involving >10,000 patients, neither total dose, dose intensity, nor AUC was correlated to the clinical effect. However, when AUC was pharmacodynamically weighed (N-weighed AUC, N-AUC = C(0.45) x T), this new descriptor was highly significantly correlated to the clinical effect (P < 0.001).

CONCLUSION

The N-AUC concept is able to characterize schedule-dependent agents and is the only descriptor of cytarabine treatment strength actually correlated to the clinical effect in AML.

Global approach to the diagnosis of leukemia using gene expression profiling

Accurate diagnosis and classification of leukemias are the bases for the appropriate management of patients. The diagnostic accuracy and efficiency of present methods may be improved by the use of microarrays for gene expression profiling. We analyzed gene expression profiles in 937 bone marrow and peripheral blood samples from 892 patients with all clinically relevant leukemia subtypes and from 45 nonleukemic controls by U133A and U133B GeneChip arrays. For each subgroup, differentially expressed genes were calculated. Class prediction was performed using support vector machines. Prediction accuracy was estimated by 10-fold cross-validation and was assessed for robustness in a 100-fold resampling approach using randomly chosen test sets consisting of one third of the samples. Applying the top 100 genes of each subgroup, an overall prediction accuracy of 95.1% was achieved that was confirmed by resampling (median, 93.8%; 95% confidence interval, 91.4%-95.8%). In particular, acute myeloid leukemia (AML) with t(15;17), AML with t(8;21), AML with inv(16), chronic lymphatic leukemia (CLL), and pro–B-cell acute lymphoblastic leukemia (pro–B-ALL) with t(11q23) were classified with 100% sensitivity and 100% specificity. Accordingly, cluster analysis completely separated all 13 subgroups analyzed. Gene expression profiling can predict all clinically relevant subentities of leukemia with high accuracy.

Thromsbospondin-1 binds to the heavy chain of elastase activated coagulation factor V (FVaHNE) and enhances thrombin generation on the surface of a promyelocytic cell line

INTRODUCTION

Thrombospondin 1 (TSP1) has the ability to bind to HL-60 cells and to reversibly inhibit human neutrophil elastase (HNE). Human factor V (FV) can be cleaved by HNE thereby providing FV with cofactor activity (FVa(HNE)). Experiments were performed to evaluate the ability of HNE expressed on the surface of HL-60 cells to generate FVa(HNE) to support thrombin generation, and to determine the effect of TSP1 on this reaction.

RESULTS

Western blot analysis showed TSP1 forming a complex with FVa(HNE) within a region corresponding to the heavy chain of FV. Enzymatic reactions were performed to determine the role of TSP1-HNE-FVa(HNE) on the surface of HL-60 cells, namely the assembly of the prothrombinase complex. Thrombin generation was measured by the chromogenic substrate S2238. Exposure of factor V to HL-60 cells prior to the addition of prothrombin and activated factor X provided FV with cofactor activity. HL-60 cells were found capable of synthesizing factor V with cofactor activity, but HL-60 cells failed to synthesize and/or to provide factor X with enzymatic activity. The ability of HL-60 cells to synthesize FV and TSP1 was demonstrated. The addition of exogenous TSP1 enhanced both the rate and amount of thrombin generated on the HL-60 cell surface.

CONCLUSION

Despite the ability of TSP1 to reversibly inhibit HNE in a purified system, TSP1 expression favors the reactions leading to thrombin generation on the HL-60 cell surface. These observations are relevant to clinical conditions where there is a prothrombotic state such as malignant tumors.