Effect of complete remission and responses less than complete remission on survival in acute myeloid leukemia: a combined Eastern Cooperative Oncology Group, Southwest Oncology Group, and M. D. Anderson Cancer Center Study

Primary refractory acute myeloid leukaemia - in search of better definitions and therapies

The definition of primary refractory acute myeloid leukaemia is the failure to achieve a response after one or two cycles of induction. Given that there are many different strategies involving different doses of cytarabine and anthracyclines, which may or may not be equivalent, and as this is an area of unmet need with the potential for the development of new agents and strategies, uniform criteria for response have been described that need to be adhered to. The outcome of patients with chemoresistant disease is poor with only a proportion of patients salvaged by allogeneic stem cell transplantation. Progress in supportive care strategies and donor identification has enabled more of these patients to undergo unrelated donor transplantation. Novel strategies and new agents directed at the biology of the disease and the mechanisms of resistance are needed.

Induction and postremission strategies in acute myeloid leukemia: what is new?

PURPOSE OF REVIEW

Induction followed by postremission therapy is recognized as the main road toward cure in acute myeloid leukemia (AML). Induction approach has not changed substantially for many years. Despite identifying numerous heterogeneous factors in AML, bench-derived insights are sluggishly translated into clinical protocols. In the current review, advances in intensified dose induction protocols, risk stratification, and disease monitoring are presented. Some promising as well as disappointing agents used for tailoring and targeting therapies in AML are also discussed.

RECENT FINDINGS

Intensifying anthracycline dose in young AML patients was recently shown to improve induction results. Importantly, maximal doses in induction have been shown to be safe also in older adults, negating a common perception that too often led to attenuation of induction therapy in this population. Novel targeted agents and the explosive number of newly identified prognostic factors or disease-specific biomarkers are promoting AML therapy toward a more personalized future.

SUMMARY

Survival of AML patients is constantly improving. High doses of 'old drugs' for chemotherapy induction, followed by a postremission combination of chemotherapy and novel targeted agents may hold the key for cure. Disease-specific molecular abnormalities may play a role in monitoring and guiding therapy.

Use of gemtuzumab ozogamycin combined with conventional chemotherapy in patients with acute myeloid leukemia

Objective: To analyze the outcome of patients treated with gemtuzumab ozogamycin combined with conventional therapy treated at Hospital Israelita Albert Einstein. Methods: 14 patients who had high risk features (secondary leukemia, unfavorable cytogenetics, and refractory disease) were treated with gemtuzumab ozogamycin combined with conventional therapy and their outcome was analysed by reviewing their medical records. Results: Overall response rate was 58%, with 43% achieving complete response, with a median follow-up of 11 months, event-free survival was 3 months. Eleven patients died, 6 of them due to refractory acute myeloid leukemia. Only four patients presented with grade 3 to 4 toxicities and only one patient had sinusoidal obstruction syndrome after bone marrow transplant. Conclusion: gemtuzumab ozogamycin combined with chemotherapy is a feasible treatment regimen in acute myeloid leukemia patients. However, further studies are necessary to clarify which subgroup of patients may beneft from this treatment.

Platelet recovery before allogeneic stem cell transplantation predicts posttransplantation outcomes in patients with acute myelogenous leukemia and myelodysplastic syndrome

Complete remission (CR) is the gold standard for assessing outcomes following chemotherapy for acute myelogenous leukemia (AML). "CRp," a response criterion defined as fulfillment of all criteria for CR except platelet count recovery to ≥100 × 10(9)/L, is associated with inferior outcomes following chemotherapy. The prognostic importance of CRp before allogeneic stem cell transplantation (allo-SCT) remains unknown. We analyzed a cohort of AML (n = 334) and myelodysplastic syndrome (MDS; n = 10) patients to determine the prognostic significance of achieving CR versus CRp before allo-SCT. At time of transplantation, 266 patients were in CR (CR1 and ≥CR2) and 78 in CRp (CR1p and ≥CR2p). Median follow-up was 38 months (3-131 months). Overall survival, progression-free survival, and nonrelapse mortality (NRM) were most favorable in patients transplanted in CR (CR1 or ≥CR2) compared with CRp (CR1p or ≥CR2p). Achieving CR is therefore associated with improved posttransplantation outcomes compared with achieving CRp and is a significant prognostic factor that needs to be considered when evaluating AML/MDS patients for clinical trials and allo-SCT.

Novel approaches to the treatment of acute myeloid leukemia

Approximately 12 000 adults are diagnosed with acute myeloid leukemia (AML) in the United States annually, the majority of whom die from their disease. The mainstay of initial treatment, cytosine arabinoside (ara-C) combined with an anthracycline, was developed nearly 40 years ago and remains the worldwide standard of care. Advances in genomics technologies have identified AML as a genetically heterogeneous disease, and many patients can now be categorized into clinicopathologic subgroups on the basis of their underlying molecular genetic defects. It is hoped that enhanced specificity of diagnostic classification will result in more effective application of targeted agents and the ability to create individualized treatment strategies. This review describes the current treatment standards for induction, consolidation, and stem cell transplantation; special considerations in the management of older AML patients; novel agents; emerging data on the detection and management of minimal residual disease (MRD); and strategies to improve the design and implementation of AML clinical trials.

Characteristics and outcome of patients with acute myeloid leukemia refractory to 1 cycle of high-dose cytarabine-based induction chemotherapy

Pretreatment characteristics and outcome of patients treated with induction regimens containing high-dose ara-C (HiDAC) at M. D. Anderson Cancer Center refractory to 1 cycle of induction were compared with similar patients achieving a complete response (CR). Among 1597 patients treated with HiDAC-based induction from 1995 to 2009, 285 were refractory to 1 cycle. Median age was 59 years (range, 18-85 years). Induction regimens included HiDAC with anthracyclines (n = 181; 64%) or HiDAC with nonanthracycline chemotherapy (n = 104; 36%). Refractory patients were older (median age, 59 vs 56 years; P < .001), more likely with unfavorable cytogenetics (P < .001) and antecedent hematologic disorder (P < .001), and had a higher presentation white blood cell count (P = .04), but not a higher incidence of FLT3 mutations (P = .85), than those achieving CR. Forty-three patients (22%) responded to salvage (35 CR and 8 CR without platelet recovery). With a median follow-up of 72 months (range, 27-118 months) in responders, 11 are alive. Nineteen patients (7%) were alive and in CR for at least 6 months, including 9 who underwent allogeneic stem cell transplantation. On multivariate analysis, severe thrombocytopenia, leukocytosis, increasing marrow blast percentage, unfavorable cytogenetics, and salvage not including allogeneic stem cell transplantation were associated with a worse survival. Alternative strategies are needed for these patients.

Complete remission and early death after intensive chemotherapy in patients aged 60 years or older with acute myeloid leukaemia: a web-based application for prediction of outcomes

BACKGROUND

About 50% of patients (age ≥60 years) who have acute myeloid leukaemia and are otherwise medically healthy (ie, able to undergo intensive chemotherapy) achieve a complete remission (CR) after intensive chemotherapy, but with a substantially increased risk of early death (ED) compared with younger patients. We verified the association of standard clinical and laboratory variables with CR and ED and developed a web-based application for risk assessment of intensive chemotherapy in these patients.

METHODS

Multivariate regression analysis was used to develop risk scores with or without knowledge of the cytogenetic and molecular risk profiles for a cohort of 1406 patients (aged ≥60 years) with acute myeloid leukaemia, but otherwise medically healthy, who were treated with two courses of intensive induction chemotherapy (tioguanine, standard-dose cytarabine, and daunorubicin followed by high-dose cytarabine and mitoxantrone; or with high-dose cytarabine and mitoxantrone in the first and second induction courses) in the German Acute Myeloid Leukaemia Cooperative Group 1999 study. Risk prediction was validated in an independent cohort of 801 patients (aged >60 years) with acute myeloid leukaemia who were given two courses of cytarabine and daunorubicin in the Acute Myeloid Leukaemia 1996 study.

FINDINGS

Body temperature, age, de-novo leukaemia versus leukaemia secondary to cytotoxic treatment or an antecedent haematological disease, haemoglobin, platelet count, fibrinogen, and serum concentration of lactate dehydrogenase were significantly associated with CR or ED. The probability of CR with knowledge of cytogenetic and molecular risk (score 1) was from 12% to 91%, and without knowledge (score 2) from 21% to 80%. The predicted risk of ED was from 6% to 69% for score 1 and from 7% to 63% for score 2. The predictive power of the risk scores was confirmed in the independent patient cohort (CR score 1, from 10% to 91%; CR score 2, from 16% to 80%; ED score 1, from 6% to 69%; and ED score 2, from 7% to 61%).

INTERPRETATION

The scores for acute myeloid leukaemia can be used to predict the probability of CR and the risk of ED in older patients with acute myeloid leukaemia, but otherwise medically healthy, for whom intensive induction chemotherapy is planned. This information can help physicians with difficult decisions for treatment of these patients.

FUNDING

Deutsche Krebshilfe and Deutsche Forschungsgemeinschaft.

New Prognostic Markers in Acute Myeloid Leukemia: Perspective from the Clinic

Acute myeloid leukemia (AML) is a disease with marked heterogeneity in both response to therapy and survival. Cytogenetics, age, and performance status have long determined prognosis and therapy. The advent of molecular diagnostics has heralded an explosion in new prognostic factors, including gene mutations in KIT, FLT3 (Fms-like tyrosine kinase 3), NPM1 (nucleophosmin 1), and CEBPA (CCAAT enhancer-binding protein-α). Microarray technology can now identify unique gene expression signatures associated with prognosis. Similarly microRNA expression, single nucleotide polymorphism arrays, and DNA methylation signatures have recently described important new prognostic subgroups of AML, and are contributing to our understanding of AML disease biology. Combined with proteomic profiling, these technologies have helped identify new targets and signaling pathways, and may soon help to identify individual patients likely to benefit from specific therapies, including allogeneic hematopoietic cell transplantation. In summary, new clinical and molecular prognostic markers have begun to significantly improve our understanding of AML biology. We are now close to a time when we will be able to use these prognostic factors and technologies to identify new targets for therapy and to determine who may benefit from that therapy, and ultimately change how we treat individual patients with AML.

How I treat acute myeloid leukemia

More than one quarter of a million adults throughout the world are diagnosed annually with acute myeloid leukemia (AML). Despite considerable progress during the past 3 decades in the therapy of AML, two-thirds of young adults and 90% of older adults still die of their disease. The reported median age has increased over the past few decades, mostly because of a greater willingness of physicians to diagnose and treat older patients, and now is 72 years. The greatest challenge is in this age group. However, much improvement in therapy is needed for all adults with AML. Recent advances in allogeneic transplantation, a better understanding of prognostic factors, and development of targeted agents have only modestly improved overall outcome when large populations of patients are considered. Although an explosion in knowledge about the molecular pathogenesis of AML has outpaced treatment advances, such insights hold promise for the development of new therapies directed at specific molecular abnormalities that perturb malignant cell survival pathways. The current approach in 2010 to the management of this disease is presented through a discussion of illustrative cases.

Shortcomings in the clinical evaluation of new drugs: acute myeloid leukemia as paradigm

Drugs introduced over the past 25 years have benefitted many patients with acute myeloid leukemia (AML) and provided cure for some. Still, AML remains difficult to treat, and most patients will eventually die from their disease. Therefore, novel drugs and drug combinations are under intense investigation, and promising results eagerly awaited and embraced. However, drug development is lengthy and costs are staggering. While the phase 1-phase 2-phase 3 sequence of clinical drug testing has remained inviolate for decades, it appears intrinsically inefficient, and scientific flaws have been noted by many authors. Of major concern is the high frequency of false-positive results obtained in phase 2 studies. Here, we review features of phase 2 trials in AML that may contribute to this problem, particularly lack of control groups, patient heterogeneity, selection bias, and choice of end points. Recognizing these problems and challenges should provide us with opportunities to make drug development more efficient and less costly. We also suggest strategies for trial design improvement. Although our focus is on the treatment of AML, the principles that we highlight should be broadly applicable to the evaluation of new treatments for a variety of diseases.