Intensive versus less-intensive antileukemic therapy in older adults with acute myeloid leukemia: A systematic review

To compare the effectiveness and safety of intensive antileukemic therapy to less-intensive therapy in older adults with acute myeloid leukemia (AML) and intermediate or adverse cytogenetics, we searched the literature in Medline, Embase, and CENTRAL to identify relevant studies through July 2020. We reported the pooled hazard ratios (HRs), risk ratios (RRs), mean difference (MD) and their 95% confidence intervals (CIs) using random-effects meta-analyses and the certainty of evidence using the GRADE approach. Two randomized trials enrolling 529 patients and 23 observational studies enrolling 7296 patients proved eligible. The most common intensive interventions included cytarabine-based intensive chemotherapy, combination of cytarabine and anthracycline, or daunorubicin/idarubicin, and cytarabine plus idarubicin. The most common less-intensive therapies included low-dose cytarabine alone, or combined with clofarabine, azacitidine, and hypomethylating agent-based chemotherapy. Low certainty evidence suggests that patients who receive intensive versus less-intensive therapy may experience longer survival (HR 0.87; 95% CI, 0.76-0.99), a higher probability of receiving allogeneic hematopoietic stem cell transplantation (RR 6.14; 95% CI, 4.03-9.35), fewer episodes of pneumonia (RR, 0.25; 95% CI, 0.06-0.98), but a greater number of severe, treatment-emergent adverse events (RR, 1.34; 95% CI, 1.03-1.75), and a longer duration of intensive care unit hospitalization (MD, 6.84 days longer; 95% CI, 3.44 days longer to 10.24 days longer, very low certainty evidence). Low certainty evidence due to confounding in observational studies suggest superior overall survival without substantial treatment-emergent adverse effect of intensive antileukemic therapy over less-intensive therapy in older adults with AML who are candidates for intensive antileukemic therapy.

Is outcome of older people with acute myeloid leukemia improving with new therapeutic approaches and stem cell transplantation?

Introduction: The clinical outcome of older patients with acute myeloid leukemia (AML) is still poor, especially for those who are unfit to treatments aimed at altering the natural course of the disease. Hypomethylating agents (HMA) offer an important therapeutic opportunity to a consistent number of patients, but long-term results are largely unsatisfactory.Area covered: Recently, a number of new agents have been registered for AML, some of which selectively available for older patient population, with promising results in terms of response rate and survival. Furthermore, the upper age limit for allogeneic stem cell transplantation is constantly increasing, so that this procedure is offered and actually given to an increasing number of older patients with AML. A literature review was conducted of the PubMed database for articles published in English as well as for abstracts from most important and recent hematology meetings on AML in older patients.Expert opinion: Appropriate selection among different options on the basis of clinical fitness and molecular findings at diagnosis as well as at relapse would result in improvement of therapeutic results, sparing unnecessary toxicity and optimizing health systems resources.

ABCB1 genetic variants in leukemias: current insights into treatment outcomes

Despite improvements in treatment of different types of leukemia, not all patients respond optimally for a particular treatment. Some treatments will work better for some, while being harmful or ineffective for others. This is due to genetic variation in the form of single-nucleotide polymorphisms (SNPs) that affect gene expression or function and cause inherited interindividual differences in the metabolism and disposition of drugs. Drug transporters are one of the determinants governing the pharmacokinetic profile of chemotherapeutic drugs. The ABCB1 transporter gene transports a wide range of drugs, including drugs used in leukemia treatment. Polymorphisms in the ABCB1 gene do affect intrinsic resistance and pharmacokinetics of several drugs used in leukemia treatment protocols and thereby affect the efficacy of treatment and event-free survival. This review focuses on the impact of three commonly occurring SNPs (1236C>T, 2677G>T/A, and 3435C>T) of ABCB1 on treatment response of various types of leukemia. From the literature available, some of the genotypes and haplotypes of these SNPs have been found to be potential determinants of interindividual variability in drug disposition and pharmacologic response in different types of leukemia. However, due to inconsistencies in the results observed across the studies, additional studies, considering novel genomic methodologies, comprehensive definition of clinical phenotypes, adequate sample size, and uniformity in all the confounding factors, are warranted.

Azacitidine in the treatment of older patients affected by acute myeloid leukemia: A report by the Rete Ematologica Pugliese (REP)

The optimal treatment of older patients (>65 years) with acute myeloid leukemia (AML) remains challenging in daily clinical practice; a choice has to be made between intensive chemotherapy and best supportive care. To guide physicians, several prognostic factors have been identified and risk scores developed. Recently, the DNA methyltransferase inhibitor azacitidine has become available for use in MDS and AML patients with up to 30% bone marrow blasts. However, limited data are available on the outcome of older unfit AML patients, regardless of their bone marrow blast count. We retrospectively analyzed the outcome of 90 newly diagnosed older unfit AML patients in 9 Institutions from the Apulia Region (REP). Responder patients (evaluation performed after 4 cycles of treatment even in cases of primary failure) showed a better overall survival than non responders (23 vs 6 months, p<.001). ECOG PS≥2 seems to be correlated with OS in multivariate analysis, while neither primary treatment failure (documented after 2 cycles) nor bone marrow blast count were correlated with a worse overall survival either at univariate (22 vs 29 months, p=.ns; 16 vs 19 months, p=.ns) or multivariate analysis. Overall, the results of our retrospective analysis seem to confirm the efficacy of AZA treatment for this unfit AML patients setting, in terms of both CR and OS, regardless of the bone marrow blasts count, while primary treatment failure should not lead to a discontinuation of treatment.

A model for the functional assessment of elderly with myeloid neoplasms

OBJECTIVE

Myeloid neoplasms are heterogeneous diseases that are more incident in the elderly. The goals of this study were to aggregate a geriatric approach to the patient assessment, to show the impact of gender, age, hemoglobin concentration and comorbidities on the functionality of elderly with myeloid neoplasms and to better understand how the instruments of functional assessment work according to the aggressiveness of the disease.

METHODS

Elderly patients (≥60 years old) with myeloid neoplasms were assessed using the Karnofsky scale, Eastern Cooperative Oncologic Group scale, and basic and instrumental activities of daily living scales. The hematopoietic cell transplantation-comorbidity index assessed the comorbidities. A mixed logistical regression model was fitted to estimate the impact of gender, age, hemoglobin concentration and the hematopoietic cell transplantation-comorbidity index on patients' functionality.

RESULTS

Eighty-two patients with a mean age of 72.8 years (range: 60-92 years) were evaluated. Eighty percent had good Karnofsky and Eastern Cooperative Oncologic Group scales and 39% were independent according to the daily living activity scales. All of the patients with poor Karnofsky and Eastern Cooperative Oncologic Group scales were classified as dependent by the daily living activity scales. The mixed logistic regression models showed that age, gender, hemoglobin concentration and the comorbidity index impacted on the daily living activity scales. Karnofsky and Eastern Cooperative Oncologic Group scales were affected by hemoglobin and the comorbidity index. The model hypothesized the hemoglobin concentration at which there was a higher risk of poor Karnofsky and Eastern Cooperative Oncologic Group scales. This hemoglobin concentration depended on comorbidities and on the aggressiveness of the myeloid neoplasm.

CONCLUSION

The geriatric approach improved the sensitivity and specificity of the patients' assessment. Hemoglobin concentration associated to the risk of poor Karnofsky and Eastern Cooperative Oncologic Group scales depended on the comorbidity score and on the disease aggressiveness. The Karnofsky and Eastern Cooperative Oncologic Group scales had higher sensitivity in patients with more aggressive diseases.

Alternative novel therapies for the treatment of elderly acute myeloid leukemia patients

With a median age at diagnosis of approximately 65-70 years, acute myeloid leukemia (AML) represents a major therapeutic challenge in the elderly. Only 30-35% of elderly patients with AML are considered eligible for intensive chemotherapy and do actually receive it. However, the long-term benefit associated with intensive chemotherapy remains marginal, and the overall outcome for this population remains poor. The remaining 60-65% of elderly AML patients receives supportive care only. Nevertheless, several studies have indicated that patients who receive any therapy had a better outcome if compared with patients who receive supportive care only. Thus, the development of novel, less toxic, targeted agents is offering new options to older AML patients who are unfit for intensive approaches. In the present review, we will report on the results achieved using intensive chemotherapy and novel agents, and will describe some of the new strategies under development for treating older AML patients.

Easily manageable prognostic factors in 152 Chinese elderly acute myeloid leukemia patients: a single-center retrospective study

We retrospectively investigated the prognostic factors of acute myeloid leukemia (AML) in 152 Chinese patients with de novo AML who were older than 60 years of age and who received treatment at our hospital. Log-rank test showed that 6 parameters including older age, higher white blood cell (WBC) counts, lactate dehydrogenase (LDH) and bone marrow (BM) blasts at diagnosis, unfavorable risk cytogenetics, and non-mutated CEBPα were significant adverse prognostic factors of overall survival (OS) for elderly AML patients (P  =  0.0013, 0.0358, 0.0132, 0.0242, 0.0236 and 0.0130, respectively). Moreover, older age and higher LDH were significant adverse predictors for relapse-free survival (RFS) (P  =  0.0447 and 0.0470, respectively). Univariate analysis revealed similar results for OS to those of the log-rank test and only higher LDH at diagnosis was a significant adverse predictor for RFS (P  =  0.028, HR: 1.979, 95%CI: 1.075–3.644). In multivariate analysis, we identified 2 trends towards independent prognostic factors for OS, including BM blasts at diagnosis (P  =  0.057, HR: 1.676, 95%CI: 0.984–2.854) and mutation status of CEBPα (P  =  0.064, HR: 4.173, 95%CI: 0.918–18.966). Our data indicated that older age, gender and a previous history of hematologic diseases resulted in lower complete remission rate (P  =  0.012, 0.051 and 0.086, respectively). We further developed an easy scoring system for predicting prognosis and response to induction therapy in older AML patients. Patients who had lower scores showed significantly longer OS and RFS (P  =  0.0006 and 0.1001, respectively) and higher CR rate (P  =  0.014). Our research is limited by its retrospective nature and the results from our study need to be further validated by prospective randomized clinical trials.

Physician's Attitude Towards Treatment of Older Patients and the Choice of Therapy

The treatment of acute myeloid leukemia in older patients is still object of controversies, because of considerable heterogeneity among patients and different characteristics in the disease. Reluctance in administering conventional intensive chemotherapy relies on life-threatening complications induced by treatment in an often frail patient population. Nonetheless, while there is general consensus on the management of frail patients with supportive care only, a wide area of uncertainty remains for a considerable proportion of patients in whom treatment beyond support is feasible, with the aim of altering the natural history of the disease. Several predictive score have been proposed in order to prevent toxicity in absence of survival advantage; however in the daily practice patients' and physician attitude does still play a major role in the final therapeutic decision.

Conventional chemotherapy or hypomethylating agents for older patients with acute myeloid leukaemia?

Acute myeloid leukaemia (AML) is the second more frequent hematologic malignancy in developed countries and primarily affects older adults with a median age at diagnosis of 69 years. Given the progressive ageing of the general population, the incidence of the disease in elderly people is expected to further increase in the years to come. Along with cytogenetics at diagnosis, age represents the most relevant prognostic factor in AML, in that the outcome steadily declines with increasing age. Reasons for poor prognosis include more frequent unfavourable karyotype and other adverse biologic characteristics, such as high rates of expression of genes drug resistance related and high prevalence of secondary AML. Noticeably, as compared with young adults, poorer results in elderly patients have been reported within any cytogenetic and molecular prognostic subgroup, because of frequent comorbid diseases, which render many patients ineligible to intensive chemotherapy. Therefore, predictive models have been developed with the aim of achieving best therapeutic results avoiding unnecessary toxicity. Following conventional induction therapy, older AML patients have complete remission rates in the range of 45-65%, and fewer than 10% of them survive for a minimum of 5 years. On the other hand, hypomethylating agents, such as azacytidine and decitabine offer the possibility of long-term disease control without necessarily achieving complete remission and can represent a reasonable alternative to intensive chemotherapy. Either intensive chemotherapy or hypomethylating agents have lights and shadows, and the therapeutic selection is often influenced by physician's and patient's attitude rather than definite criteria. Research is progress in order to assess predictive biologic factors, which would help clinicians in the selection of patients who can take actual benefit from different therapeutic options.

Acute myeloid leukaemia in adults

The outlook for patients with acute myeloid leukaemia has improved in the past 30 years. Unlike other cancers, much of this progress is attributable to refinement of supportive treatment, rather than the introduction of new drugs. New antibacterial and antifungal agents, antiemetics, and improved transfusion support have decreased the rate of early death, and morbidity and mortality from allogeneic stem cell transplantation has been substantially reduced. However, more than half of young adult patients and about 90% of older patients still die from their disease. Refractoriness to initial induction treatment and, more frequently, relapse after complete remission, are still the main obstacles to cure. Accordingly, new treatment approaches with mechanisms of action different from those of conventional chemotherapy are needed. Our knowledge of the various chromosomal and molecular abnormalities implicated in the pathogenesis of the many subtypes of the disease has greatly expanded; as a result, clinical research is moving towards the investigation of new non-cytotoxic agents in combination with chemotherapy. The goal is to target the molecular abnormalities identified at diagnosis; however, several aberrations can coexist in subclones of acute myeloid leukaemia, making the disease less likely to be inhibited by a single agent.

ABCB1 genetic variation and P-glycoprotein expression/activity in a cohort of Brazilian acute myeloid leukemia patients

PURPOSE

Polymorphisms in the ABCB1 gene may influence P-glycoprotein (Pgp) expression and/or activity. Because the population in Brazil is markedly heterogeneous, we analyzed the relationship between ABCB1 polymorphisms and Pgp expression/activity in Brazilian acute myeloid leukemia (AML) patients.

METHODS

Acute myeloid leukemia samples from 109 patients were studied. ABCB1 gene variants rs1128503 (C1236T) and rs1045643 (C3435T) were analyzed by PCR-RFLP assay. Pgp expression and Pgp activity were analyzed by flow cytometry.

RESULTS

There was a similar distribution of Pgp expression and activity on polymorphisms C1236T, C1236C, and T1236T for exon 12, and C3435T, C3435C, and T3435T for exon 26. An exception was observed in the lowest ratio of mean fluorescence intensity (MFI) median for Pgp expression in the TT genotype for both studied exons, and its correspondence to a low MFI median for Pgp activity. Pgp expression did not show impact on the response to remission induction therapy, but the MFI median of Pgp expression in the remission failure group was higher than that of the complete remission (CR) group of patients (p = 0.04). Overall survival (OS) was significantly influenced by CR (p = 0.0001). Better 5-year OS and 5-year event-free survival rates (p = 0.04 and p = 0.007, respectively) were achieved in patients presenting the genetic variant CC in exon 12 followed by those presenting the variant CT in exon 26 (p = 0.001).

CONCLUSIONS

Polymorphisms in the ABCB1 gene and the levels of Pgp expression could be useful to identify prognostic in AML patients.

New agents for acute myeloid leukemia: is it time for targeted therapies?

INTRODUCTION

The prognosis of acute myeloid leukemia (AML) is improved in the last two decades, even though induction and consolidation chemotherapy has not involved new drugs. The more effective use of well-known agents as well as refinement of supportive care during the inevitable phase of severe pancytopenia following intensive chemotherapy accounts for the reduction of treatment-related death rate. In addition, mortality due to allogeneic and autologous stem cell transplantation has also been reduced, due to adoption of more effective therapies for graft versus host disease and other transplant-related complications.

AREAS COVERED

The multitude of chromosomal and molecular abnormalities makes the treatment of AML a challenging prospect. In addition, genetic aberrations are not mutually exclusive and coexist in the leukemic cells. As a consequence, the clinical development of new biologic agents proceeds slowly. Data for this review were identified from PubMed and references from relevant articles published in English from 2000 to 2011.

EXPERT OPINION

In Phase II studies, different new agents have been found to be active in AML and are currently under investigation in Phase III trials also in combination with conventional chemotherapy. In the near future, we would have more information about the possibility of introducing new drugs into daily practice.