Interpretation of clinical endpoints in trials of acute myeloid leukemia

Designing patient-oriented combination therapies for acute myeloid leukemia based on efficacy/toxicity integration and bipartite network modeling

Acute myeloid leukemia (AML), a heterogeneous and aggressive blood cancer, does not respond well to single-drug therapy. A combination of drugs is required to effectively treat this disease. Computational models are critical for combination therapy discovery due to the tens of thousands of two-drug combinations, even with approved drugs. While predicting synergistic drugs is the focus of current methods, few consider drug efficacy and potential toxicity, which are crucial for treatment success. To find effective new drug candidates, we constructed a bipartite network using patient-derived tumor samples and drugs. The network is based on drug-response screening and summarizes all treatment response heterogeneity as drug response weights. This bipartite network is then projected onto the drug part, resulting in the drug similarity network. Distinct drug clusters were identified using community detection methods, each targeting different biological processes and pathways as revealed by enrichment and pathway analysis of the drugs' protein targets. Four drugs with the highest efficacy and lowest toxicity from each cluster were selected and tested for drug sensitivity using cell viability assays on various samples. Results show that ruxolitinib-ulixertinib and sapanisertib-LY3009120 are the most effective combinations with the least toxicity and the best synergistic effect on blast cells. These findings lay the foundation for personalized and successful AML therapies, ultimately leading to the development of drug combinations that can be used alongside standard first-line AML treatment.

Comparative Efficacy of Venetoclax-Based Combination Therapies and Other Therapies in Treatment-Naive Patients With Acute Myeloid Leukemia Ineligible for Intensive Chemotherapy: A Network Meta-Analysis

OBJECTIVES

This network meta-analysis (NMA) assessed the efficacy of venetoclax (VEN) + azacitidine (AZA) and VEN + low-dose cytarabine (LDAC) compared with AZA, LDAC, and decitabine monotherapies and best supportive care (BSC) in adults with untreated acute myeloid leukemia ineligible for intensive chemotherapy.

METHODS

A systematic literature review and feasibility assessment was conducted to select phase III randomized controlled trials for inclusion in the NMA. Complete remission + complete remission with incomplete blood count recovery and overall survival (OS) were compared using a Bayesian fixed-effects NMA. Treatments were ranked using surface under the cumulative ranking curves (SUCRAs) with higher values indicating a higher likelihood of being effective.

RESULTS

A total of 1140 patients across 5 trials were included. VEN + LDAC (SUCRA 91.4%) and VEN + AZA (87.5%) were the highest ranked treatments for complete remission + complete remission with incomplete blood count recovery. VEN + LDAC was associated significantly higher response rates versus AZA (odds ratio 5.64), LDAC (6.39), and BSC (23.28). VEN + AZA was also associated significantly higher response rates than AZA (5.06), LDAC (5.74), and BSC (20.68). In terms of OS, VEN + AZA (SUCRA: 95.2%) and VEN + LDAC (75.9%) were the highest ranked treatments. VEN + AZA was associated with significant improvements in OS compared with AZA (hazard ratio 0.66), LDAC (0.57), and BSC (0.37), and VEN + LDAC was associated with significant improvements in OS compared with LDAC (0.70) and BSC (0.46).

CONCLUSIONS

VEN + AZA and VEN + LDAC demonstrated improved efficacy compared with alternative therapies among treatment-naive patients with acute myeloid leukemia ineligible for intensive chemotherapy.

Defining Current Patterns of Blood Product Use during Intensive Induction Chemotherapy in Newly Diagnosed Acute Myeloid Leukemia Patients

Introduction

Blood product transfusion retains a critical role in the supportive care of patients with acute myeloid leukemia (AML). Whereas previous studies have shown increased transfusion dependency to portend inferior outcome, predictive factors of an increased transfusion burden and the prognostic impact of transfusion support have not been assessed recently.

Methods/Patients

We performed a retrospective analysis on a recent cohort of patients given intensive induction chemotherapy in 2014-2022.

Results

The analysis comprised 180 patients with a median age of 57 years with 80% designated as de novo AML. Fifty-four patients (31%) were FLT3-ITD mutated, and 73 patients (42%) harbored NPM1. Favorable risk and intermediate risk ELN 2017 patients accounted for 43% and 34% of patients, respectively. The median number of red blood cell (RBC) and platelet units given during induction were 9 and 7 units, respectively. Seventeen patients (9%) received cryoprecipitate, and fresh frozen plasma (FFP) was given to 12 patients (7%). Lower initial hemoglobin and platelet levels were predictive of increased use of RBC (p < 0.0001) and platelet transfusions (p < 0.0001). FFP was significantly associated with induction related mortality (42% vs. 5%; p < 0.0001) and with FLT3-ITD (72% vs. 28%; p = 0.004). Blood group AB experienced improved mean overall survival compared to blood group O patients (4.1 years vs. 2.8 years; p = 0.025). In multivariate analysis, increased number of FFP (hazard ratio [HR], 4.23; 95% confidence interval [CI], 2.1-8.6; p < 0.001) and RBC units (HR, 1.8; 95% CI, 1.2-2.8; p = 0.008) given was associated with inferior survival.

Conclusion

Transfusion needs during induction crucially impact the clinical trajectory of AML patients.

Endpoint selection and evaluation in hematology studies

Observational studies and clinical trials in hematology aim to examine treatments for blood disorders. The outcomes being studied must address the goals of the study and provide meaningful information about treatment course, disease progression, describe patients' survival experience and quality of life. Endpoints are the specific measures of these outcomes, and much consideration should be given to their selection. In this review, we describe the outcomes and endpoints frequently used in studying hematologic diseases and provide general guidelines for their statistical analysis. The main focus is on clinical outcomes which are commonly used in establishing treatment safety and efficacy. We also briefly discuss the role surrogate and composite endpoints play in hematology studies. The importance of patient reported outcomes to comprehensive assessment of the treatment effectiveness is highlighted. Provided practical considerations for choosing primary and secondary endpoints may be helpful in designing hematology clinical trials.

The occurrence of thrombosis during intensive chemotherapy treatment for acute myeloid leukemia patients does not impact on long-term survival

Venous thromboembolism (VTE) is frequently seen in acute myeloid leukemia (AML) patients and presents a significant clinical challenge. The association of VTE during intensive chemotherapy with risk models such as the Medical Research Council (MRC) cytogenetic-based assessment and the European LeukemiaNet (ELN) 2017 molecular risk model have not been rigorously evaluated. Additionally, there is a paucity of data pertaining to the long-term prognostic impact of VTE in AML patients. We performed an analysis of baseline parameters of AML patients diagnosed with VTE during intensive chemotherapy and compared them with patients without VTE. The analyzed cohort consisted of 335 newly diagnosed AML patients with a median age of 55 years. Thirty-five patients (11%) were classified as MRC favorable risk, 219 (66%) patients as intermediate risk, 58 patients (17%) as adverse risk. Per ELN 2017, 132 patients (40%) had favorable risk disease, 122 patients (36%) intermediate risk, and 80 patients (24%) had adverse risk. VTE was seen in 33 patients (9.9%), occurring mostly during induction (70%), and required catheter removal in 9 patients (28%). Baseline clinical, laboratory, molecular, and ELN 2017 parameters were not significantly different groups. However, MRC intermediate-risk group patients were significantly more likely to experience thrombosis compared to favorable risk and adverse risk patients (12.8% versus 5.7% and 1.7%, respectively; p = 0.049). Median overall survival was not significantly impacted by the diagnosis of thrombosis (3.7 years versus 2.2 years; p = 0.47). VTE is tightly associated with temporal and cytogenetic parameters in AML but does not significantly impact on long-term outcomes.

Use of endpoints in phase III randomized controlled trials for acute myeloid leukemia over the last 15 years: a systematic review

We systematically evaluated the primary and secondary endpoints used in acute myeloid leukemia (AML) phase III randomized controlled trials (RCTs). We included 238 phase III AML RCTs in the past 15 years that reported 279 primary endpoints and 657 secondary endpoints. Overall survival (OS), progression-free survival (PFS), event-free survival (EFS), and complete remission (CR) were primary endpoints in 120 (43%), 34 (12%), 30 (11%), and 41 (15%) studies, respectively. OS (12.5%), PFS (13.2%), CR (14%), safety (11%), and EFS (9%) were commonly reported secondary endpoints. Among primary endpoints, a higher use of OS (OR 2.03, 95%CI 1.10-3.75, p = 0.023) and lower use of PFS (OR 0.25, 95%CI 0.12-0.52, p < 0.001) was observed from 2014 to 2021 compared to 2006-2013; CR was frequently used in relapsed/refractory compared to frontline RCTs (OR 2.20, 95%CI 1.11-4.38, p = 0.025); EFS was frequently used in frontline compared to relapsed/refractory AML RCTs (OR 10.11, 95%CI 1.34-76.34, p = 0.025). A higher trend in the use of clinically meaningful and objective endpoint of OS over the last 15 years.

Wilms tumor 1 gene expression in acute myeloid leukemia: prognostic significance and usefulness in minimal residual disease monitoring—a case–control study

Background

Minimal residual disease (MRD), which is characterized as leukemic cells at a level below morphologic detection, has been connected to the risk of relapse in acute myeloid leukemia. In 80–90% of acute myeloid leukemia (AML) patients, the Wilms tumor (WT1) gene is overexpressed at the mRNA level. In our prospective study, a total of 55 patients were enrolled in the study. Group I involved 40 AML patients and group II involved 15 patients healthy controls. WT1 gene expression was quantified using quantitative real-time PCR on bone marrow samples from AML patients at initial diagnosis and at day 28 after induction chemotherapy, and compared to 15 healthy controls in group II. Follow up of patients for prognosis evaluation was assessed. IBM SPSS software was used to capture and analyses the data.

Results

At diagnosis, the mean WT1 transcript value in AML patients was substantially higher than the expression observed in control patient’s Bone marrow. There was no statistically relevant relationship between the onset of relapse and WT1 expression. Patients with WT1 overexpression at diagnosis had a shorter overall survival than patients with negative WT1 expression.

Conclusions

Wilms tumor 1 gene expression was found to be significantly higher in AML patients than control cases, overall, our results confirmed the prognostic significance of WT1 overexpression in AML patients. Our findings support the application of MRD in AML patients based on WT1 overexpression.

Contemporary evaluation of acute myeloid leukemia patients with long-term survival exceeding five years

OBJECTIVES

Define clinical and laboratory attributes of acute myeloid leukemia (AML) patients with long-term survival exceeding five years and compare them with AML patients succumbing to disease within two years of diagnosis.

METHODS

A retrospective analysis of AML patients alive at least five years from the time of initial diagnosis. Baseline clinical data were compared with patients who died within two years of diagnosis.

RESULTS

The long-term cohort consisted of 93 patients treated in 2007-2016 with a median follow-up duration of 7.7 years (range 5-13.6 years). European LeukemiaNet (ELN) 2017 favorable risk patients accounted for 60% of the cohort. All long-term survivors achieved remission following induction chemotherapy. Multivariate analysis showed that compared with 132 patients experiencing death within 2 years of diagnosis, long term survivors were more likely to be of younger age [odds ratio (OR), 0.92; 95% confidence interval (CI), 0.9-0.95; p<0.001], have a lower initial WBC count (OR, 0.58; 95% CI, 0.43-0.79; p=0.0004), undergo an allogeneic stem cell transplantation (OR, 7.95; 95% CI, 3.07-20.59; p<0.0001), and harbor favorable risk cytogenetics (OR, 0.03; 95% CI, 0.006-0.23; p=0.0004).

CONCLUSIONS

Long term survival of AML is seen in a distinct demographic and biologic patient subset.

A retrospective comparison of salvage intensive chemotherapy versus venetoclax-combined regimen in patients with relapsed/refractory acute myeloid leukemia (AML)

Background:

Evidence that a venetoclax (VEN)-combined regimen is effective in relapsed/refractory acute myeloid leukemia (R/R AML) is emerging. However, it is unknown how VEN-combined low intensity treatment compares to intensive chemotherapy (IC) in medically fit patients with R/R AML.

Methods:

We compared AML patients who received IC (n = 89) to those who received a VEN in combination with hypomethylating agents or low dose cytarabine (VEN combination) (n = 54) as their first- or second-line salvage after failing anthracycline-containing intensive chemotherapy.

Results:

The median age was 49 years, and significantly more patients in the VEN combination group were in their second salvage and had received prior stem cell transplantation (SCT). Overall response rates including CR, CRi, and MLFS were comparable (44.0% for IC vs. 59.3% for VEN combination, p = 0.081), but VEN combination group compared to IC group tended to show lower treatment related mortality. The rate of bridging to SCT was the same (68.5%), but the percentage of SCT at blast clearance was significantly higher in the VEN-combined group (62.3% vs. 86.5%, p = 0.010). After median follow-up periods of 22.5 (IC) and 11.3 months (VEN combination), the median overall survival was 8.9 (95% CI, 5.4-12.4) and 12.4 months (95% CI, 9.5-15.2) (p = 0.724), respectively.

Conclusion:

VEN combination provides a comparable anti-leukemic response and survival to salvage IC, and provide a bridge to SCT with better disease control in medically-fit patients with R/R AML.

Acute Myeloid Leukemia Patients Requiring Two Cycles of Intensive Induction for Attainment of Remission Experience Inferior Survival Compared with Patients Requiring a Single Course of Induction Chemotherapy

BACKGROUND

Achievement of initial remission remains the most important clinical factor predicting long term survival in acute myeloid leukemia (AML) patients treated with intensive chemotherapy. Yet, whether the patient subset in need of a second cycle of intensive induction chemotherapy to reach remission experiences inferior outcomes compared to patients reaching remission after a single cycle of therapy, remains uncertain.

PATIENTS AND METHODS

Retrospective analysis of 302 consecutive AML patients treated with intensive induction chemotherapy in our institution in 2007-2020.

RESULTS

Median patient age was 55 years with a median follow-up duration of 23 months. In terms of European LeukemiaNet (ELN) 2017 classification, 122 patients (40%) were designated as favorable risk disease, 108 patients (36%) were intermediate risk, and 71 patients (24%) were adverse risk. A hundred and seventy-seven patients (60%) attained remission following initial chemotherapy while 58 patients (20%) required an additional cycle of intensive chemotherapy for remission. Patients requiring 2 cycles to reach remission were less likely to be NPM1 mutated (33% versus 51%; P=.025) or be in the ELN 2017 favorable risk category (25% versus 57%; P<.001). In multivariate analysis achievement of remission following 2 cycles of intensive compared with a single cycle resulted in significantly inferior survival [hazard ratio (HR)=1.67, 95% CI, 1.07-2.59; P=.025] whereas leukemia-free survival was not significantly impacted (HR=1.26, 95% CI, 0.85-1.85) (P=.23). Relapse rates also did not differ to a significant degree between groups (45% versus 47%, P=.8).

CONCLUSION

Attainment of an early remission significantly impacts long term survival in AML patients.

European LeukemiaNet 2017 risk stratification for acute myeloid leukemia: validation in a risk-adapted protocol

The ELN 2017 classification has been validated in a risk-adapted intensive protocol, supporting its utility to predict outcome.

Within the ELN 2017 adverse group, there is a subset of patients (inv(3) and TP53 abnormalities) with a particularly poor prognosis.

The 2017 European LeukemiaNet (ELN 2017) guidelines for the diagnosis and management of acute myeloid leukemia (AML) have become fundamental guidelines to assess the prognosis and postremission therapy of patients. However, they have been retrospectively validated in few studies with patients included in different treatment protocols. We analyzed 861 patients included in the Cooperativo Para el Estudio y Tratamiento de las Leucemias Agudas y Mielodisplasias-12 risk-adapted protocol, which indicates cytarabine-based consolidation for patients allocated to the ELN 2017 favorable-risk group, whereas it recommends allogeneic stem cell transplantation (alloSCT) as a postremission strategy for the ELN 2017 intermediate- and adverse-risk groups. We retrospectively classified patients according to the ELN 2017, with 327 (48%), 109 (16%), and 245 (36%) patients allocated to the favorable-, intermediate-, and adverse-risk group, respectively. The 2- and 5-year overall survival (OS) rates were 77% and 70% for favorable-risk patients, 52% and 46% for intermediate-risk patients, and 33% and 23% for adverse-risk patients, respectively. Furthermore, we identified a subgroup of patients within the adverse group (inv(3)/t(3;3), complex karyotype, and/or TP53 mutation/17p abnormality) with a particularly poor outcome, with a 2-year OS of 15%. Our study validates the ELN 2017 risk stratification in a large cohort of patients treated with an ELN-2017 risk-adapted protocol based on alloSCT after remission for nonfavorable ELN subgroups and identifies a genetic subset with a very poor outcome that warrants investigation of novel strategies.

Donor lymphocyte infusions after first allogeneic hematopoietic stem-cell transplantation in adults with acute myeloid leukemia: a single-center landmark analysis

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is potentially curative for acute myeloid leukemia (AML). The inherent graft-versus-leukemia activity (GvL) may be optimized by donor lymphocyte infusions (DLI). Here we present our single-center experience of DLI use patterns and effectiveness, based on 342 consecutive adult patients receiving a first allo-HSCT for AML between 2009 and 2017. The median age at transplantation was 57 years (range 19-79), and the pre-transplant status was active disease in 58% and complete remission (CR) in 42% of cases. In a combined landmark analysis, patients in CR on day +30 and alive on day +100 were included. In this cohort (n=292), 93 patients received cryopreserved aliquots of peripheral blood-derived grafts for DLI (32%) and median survival was 55.7 months (2-year/5-year probability: 62%/49%). Median survival for patients receiving a first dose of DLI "preemptively," in the absence of relapse and guided by risk marker monitoring (preDLI; n=42), or only after hematological relapse (relDLI; n=51) was 40.9 months (2-year/5-year: 64%/43%) vs 10.4 months (2-year/5-year: 26%/10%), respectively. Survival was inferior when preDLI was initiated at a time of genetic risk marker detection vs mixed chimerism or clinical risk only. Time to first-dose preDLI vs time to first-dose relDLI was similar, suggesting that early warning and intrinsically lower dynamics of AML recurrence may contribute to effectiveness of preDLI-modified GvL activity. Future refinements of the preemptive DLI concept will benefit from collaborative efforts to diagnose measurable residual disease more reliably across the heterogeneous genomic spectrum of AML.

Adjunctive Volasertib in Patients With Acute Myeloid Leukemia not Eligible for Standard Induction Therapy: A Randomized, Phase 3 Trial

In this phase 3 trial, older patients with acute myeloid leukemia ineligible for intensive chemotherapy were randomized 2:1 to receive the polo-like kinase inhibitor, volasertib (V; 350 mg intravenous on days 1 and 15 in 4-wk cycles), combined with low-dose cytarabine (LDAC; 20 mg subcutaneous, twice daily, days 1–10; n = 444), or LDAC plus placebo (P; n = 222). Primary endpoint was objective response rate (ORR); key secondary endpoint was overall survival (OS). Primary ORR analysis at recruitment completion included patients randomized ≥5 months beforehand; ORR was 25.2% for V+LDAC and 16.8% for P+LDAC (n = 371; odds ratio 1.66 [95% confidence interval (CI), 0.95–2.89]; P = 0.071). At final analysis (≥574 OS events), median OS was 5.6 months for V+LDAC and 6.5 months for P+LDAC (n = 666; hazard ratio 0.97 [95% CI, 0.8–1.2]; P = 0.757). The most common adverse events (AEs) were infections/infestations (grouped term; V+LDAC, 81.3%; P+LDAC, 63.5%) and febrile neutropenia (V+LDAC, 60.4%; P+LDAC, 29.3%). Fatal AEs occurred in 31.2% with V+LDAC versus 18.0% with P+LDAC, most commonly infections/infestations (V+LDAC, 17.1%; P+LDAC, 6.3%). Lack of OS benefit with V+LDAC versus P+LDAC may reflect increased early mortality with V+LDAC from myelosuppression and infections.

Guidance for biostatisticians on their essential contributions to clinical and translational research protocol review

Rigorous scientific review of research protocols is critical to making funding decisions, and to the protection of both human and non-human research participants. Given the increasing complexity of research designs and data analysis methods, quantitative experts, such as biostatisticians, play an essential role in evaluating the rigor and reproducibility of proposed methods. However, there is a common misconception that a statistician's input is relevant only to sample size/power and statistical analysis sections of a protocol. The comprehensive nature of a biostatistical review coupled with limited guidance on key components of protocol review motived this work. Members of the Biostatistics, Epidemiology, and Research Design Special Interest Group of the Association for Clinical and Translational Science used a consensus approach to identify the elements of research protocols that a biostatistician should consider in a review, and provide specific guidance on how each element should be reviewed. We present the resulting review framework as an educational tool and guideline for biostatisticians navigating review boards and panels. We briefly describe the approach to developing the framework, and we provide a comprehensive checklist and guidance on review of each protocol element. We posit that the biostatistical reviewer, through their breadth of engagement across multiple disciplines and experience with a range of research designs, can and should contribute significantly beyond review of the statistical analysis plan and sample size justification. Through careful scientific review, we hope to prevent excess resource expenditure and risk to humans and animals on poorly planned studies.

Immune landscapes predict chemotherapy resistance and immunotherapy response in acute myeloid leukemia

Acute myeloid leukemia (AML) is a molecularly and clinically heterogeneous hematological malignancy. Although immunotherapy may be an attractive modality to exploit in patients with AML, the ability to predict the groups of patients and the types of cancer that will respond to immune targeting remains limited. This study dissected the complexity of the immune architecture of AML at high resolution and assessed its influence on therapeutic response. Using 442 primary bone marrow samples from three independent cohorts of children and adults with AML, we defined immune-infiltrated and immune-depleted disease classes and revealed critical differences in immune gene expression across age groups and molecular disease subtypes. Interferon (IFN)-γ-related mRNA profiles were predictive for both chemotherapy resistance and response of primary refractory/relapsed AML to flotetuzumab immunotherapy. Our compendium of microenvironmental gene and protein profiles provides insights into the immuno-biology of AML and could inform the delivery of personalized immunotherapies to IFN-γ-dominant AML subtypes.

Clinical value of event-free survival in acute myeloid leukemia

The value of event-free survival (EFS) as an end point in acute myeloid leukemia (AML) trials has been questioned. We hypothesized that rather than a surrogate for overall survival (OS), improvement in EFS may decrease the use of health care. In this retrospective study, we identified 400 patients with AML who were treated on first-line therapy trials and had OS between 2 and 36 months. We captured health care use from diagnosis until death or until the patient was censored at stem cell transplantation (SCT). We used correlation and regression analysis to determine the relation between health care use and EFS. Among patients with newly diagnosed AML, 35% had adverse-risk AML, 48% received intensive chemotherapy, and 28% received hypomethylating agents. The median EFS censored at SCT was 9.7 months. Longer EFS led to a significant decline in health care use regardless of OS. This held true for all observations, including overall health care use (r = -0.45), sum of clinic visits, emergency room visits, hospitalizations, consultations (r = -0.44), sum of invasive procedures, laboratory and imaging studies (r = -0.51), and blood product transfusions (r = -0.19). These correlations were stronger for patients who achieved a complete remission and held true across age, treatment, and disease risk subgroups. In patients with newly diagnosed AML, improvement in EFS correlates with a decrease in all health care use irrespective of OS duration.

Prognostic Impact of Serum Growth Differentiation Factor 15 Level in Acute Myeloid Leukemia Patients

Growth differentiation factor 15 (GDF15) plays an important role in cancer pathophysiology and prognosis. However, limited studies analyzed its level and prognostic value in acute myeloid leukemia (AML) patients. This study included 56 adult AML patients. Serum GDF15 level was measured at diagnosis in all patients by enzyme-linked immunosorbent assay. Remission and survival statuses were assessed at 90 days following treatment. GDF15 level was significantly higher in patients than in controls (P < 0.001). GDF15 level correlated positively with age (P < 0.001), hemoglobin level (P = 0.027), and platelet count (P = 0.024). High GDF15 above the median level was associated with inferior OS (P = 0.044) together with high platelet count (P = 0.006) and high bone marrow blast percent (P = 0.038). There was no statistically significant difference between patients with GDF15 above and below the median level regarding DFS (P = 0.881). On multivariate analysis for OS, GDF15 level was an independent risk factor (P = 0.047). In conclusion, serum GDF15 level is significantly elevated in AML patients and high GDF15 level is associated with inferior OS.

Two decades of targeted therapies in acute myeloid leukemia

Precision medicine is gaining importance in the treatment of acute myeloid leukemia (AML). Objectively reviewing past and current knowledge aids guiding future research. Therefore, we provide a complete overview of all phase II and phase III trials investigating targeted therapies in AML and their primary endpoints over the past two decades in perspective of their clinical benefit. We assessed whether drugs were primarily designed to treat AML or were repurposed and how successful they were based on progression of distinct drugs from phase II to phase III to FDA-approval. Between January 2000 and September 2020, 167 agents with 96 targets were investigated in 397 phase II trials. Twenty-eight agents were steered towards phase III, after three phase II trials on average. Repurposed drugs less often advanced in clinical development than drugs primarily developed for AML. Composite responses were the most prevalent primary endpoints in phase II. Of the eight FDA-approved drugs, none investigated quality of life at time of approval, and three out of eight have yet to show benefit in overall survival. Returns on targeted therapy research remain lean for AML patients. Future trials should not overlook non-targeted agents and foremost study endpoints proven to predict patient well-being.

Clinical Trial Design and Drug Approval in Oncology: A Primer for the Advanced Practitioner in Oncology

Evidenced-based practice requires timely and accurate integration of scientific advances. This presents a challenge for the oncology clinician given the robust pace of scientific discovery and the increasing number of new drug approvals and expanded indications for previously approved drugs. All currently available antineoplastic therapies have been developed through the clinical trials process. Advanced practitioners (APs) in oncology are often involved in the conduct of clinical trials as primary investigators, sub-investigators, study coordinators, or in the delivery and monitoring of care to patients enrolled in these trials. A prerequisite to evidenced-based practice is understanding how clinical trials are conducted and how to critically analyze published results of studies leading to U.S. Food & Drug Administration approval. Any AP involved in the clinical management and supportive care of patients receiving antineoplastic therapies should be able to critically review published data to glean findings that warrant a change in practice. The goals of this manuscript are to summarize key elements of the clinical trial process for oncology drug development and approval in the United States and to provide a primer for the interpretation of clinical data.

Gene expression analysis of activating and inhibitory receptors of natural killer cells in patients with acute myeloblastic leukemia

PURPOSE

Natural killer (NK) cells are cytotoxic lymphocytes, which have long been known to play an essential role in immune surveillance of tumor cells. The results of several clinical studies imply evidence of impaired activity of NK cells in acute myeloblastic leukemia (AML). The aim of this study was to investigate the gene expression of activating and inhibitory receptors of NK cells in patients with newly diagnosed AML before and after induction therapy using 7 + 3 regimen in comparison to healthy donors.

MATERIALS AND METHODS

Sixteen AML patients aged 16-64 years as well as 16 matched healthy individuals were studied. Peripheral blood samples from patients were obtained in two steps, namely, in newly diagnosed patients and 28 days after receiving induction therapy. Real-time PCR was performed to evaluate the expression levels of activating receptors, including DNAM-1 and NKp46 as well as inhibitory receptors of KIR2DL1 and NKG2A.

RESULTS

Our results demonstrated that the newly diagnosed patients showed over 50% decrease in NKp46 expression and a 6-fold increase in KIR2DL1 expression compared to healthy controls. The mRNA expression analysis in patients after induction therapy suggested a significant decrease in mRNA expressions of KIR2DL1 and NKG2A in comparison to newly diagnosed patients.

CONCLUSION

Herewith, we show a statistical difference in mRNA expression levels of activating (NKp46) and inhibitory receptors from NK cells in newly diagnosed AML patients when compared with healthy controls or patients who received induction therapy, supporting the findings of researchers who reported the impaired NK cells cytotoxicity in AML patients.

Lyon-University Hospital Experience with Gemtuzumab Ozogamicin Therapy in Acute Myeloid Leukemia: a 'Real-Life' Study

Ninety-four adults with newly diagnosed or relapsed/refractory acute myeloid leukemia (AML) were treated with fractionated doses of gemtuzumab ozogamicin (GO) at one-single French center over ten years. We attempted to define predictive factors for response and survival. The overall response rate was 70% (86% in newly diagnosed and 65% in relapsed/refractory AML). Mortality during induction was 6%. Disease-free survival (DFS) and overall survival at three years after GO treatment was 36% and 31%, respectively. Median DFS in relapsed/refractory patients was eight months with a 3-year DFS at 34%. Among remitters, allogeneic hematopoietic stem cell transplantation (HSCT) can be performed in 28 cases (42%), including two patients in first-line therapy and 26 in further line. In relapsed/refractory patients undergoing allogeneic HSCT after responding to GO therapy, the median DFS was not reached. Incidences of transplant-related mortality, grade ≥ 3 acute graft-versus-host (GvH) disease, and extensive chronic GvH disease were 11%, 14%, and 25%, respectively. No sinusoidal obstruction syndromes were reported among allografted patients as among the other patients in the studied cohort. GO-based chemotherapy is a viable option for the treatment of relapsed/refractory AML patients and is a feasible schedule as a bridge to allogeneic transplant.

MIRROS: a randomized, placebo-controlled, Phase III trial of cytarabine ± idasanutlin in relapsed or refractory acute myeloid leukemia

Patients with refractory or relapsed acute myeloid leukemia (R/R AML) have a poor prognosis, with a high unmet medical need. Idasanutlin is a small-molecule inhibitor of MDM2, a negative regulator of tumor suppressor p53. By preventing the p53–MDM2 interaction, idasanutlin allows for p53 activation, particularly in patients with TP53 wild-type (WT) status. MIRROS (NCT02545283) is a randomized Phase III trial evaluating idasanutlin + cytarabine versus placebo + cytarabine in R/R AML. The primary end point is overall survival in the TP53-WT population. Secondary end points include complete remission rate (cycle 1), overall remission rate (cycle 1) and event-free survival in the TP53-WT population. MIRROS has an innovative design that integrates a stringent interim analysis for futility; continuation criteria were met in mid-2017 and accrual is ongoing.

Trial registration number: NCT02545283

A phase 1 study of azacitidine with high-dose cytarabine and mitoxantrone in high-risk acute myeloid leukemia

In this phase 1 study, azacitidine (AZA) was given before high-dose cytarabine (HiDAC) and mitoxantrone (mito) based on the hypothesis that epigenetic priming with a hypomethylating agent before cytotoxic chemotherapy would improve response rates in patients with high-risk acute myeloid leukemia (AML), including relapsed/refractory disease. The primary objective was to establish the recommended phase 2 dose of AZA given before standard HiDAC/mito. In a dose escalation scheme, 46 patients (median age, 66 years) received AZA at 37.5, 50, or 75 mg/m2 subcutaneously or IV once daily on days 1 to 5 followed by HiDAC (3000 mg/m2) and mitoxantrone (30 mg/m2) once each on days 6 and 10 (the HiDAC/mito dose was reduced 33% in elderly subjects). Two dose-limiting toxicities occurred (both in the same patient): acute liver failure and kidney injury at the 50 mg/m2 dose. The 30-day induction death rate was 2.2% (1 of 46). The overall response rate, including complete remission and complete remission with incomplete count recovery, was 61% (28 of 46). Previously untreated patients aged ≥60 years with therapy-related AML and de novo AML were more likely to respond than untreated patients with AML progressing from an antecedent hematologic disorder (myelodysplastic syndrome and chronic myelomonocytic leukemia). Patients with favorable European Leukemia Network risk (P = .008), NPM1 mutations (P = .007), or IDH2 mutations (P = .03) were more likely to respond, and those with TP53 mutations (P = .03) were less likely to respond. The recommended phase 2 dose of AZA is 75 mg/m2 per day on days 1 to 5 followed by HiDAC (3000 mg/m2) and mitoxantrone (30 mg/m2) once each on days 6 and 10. This trial was registered at www.clinicaltrials.gov as #NCT01839240.

Flow-Cytometric Monitoring of Minimal Residual Disease in Pediatric Patients With Acute Myeloid Leukemia: Recent Advances and Future Strategies

Minimal residual disease (MRD) by multiparametric flow cytometry (MFC) has been recently shown as a strong and independent prognostic marker of relapse in pediatric AML (pedAML) when measured at specific time points during Induction and/or Consolidation therapy. Hence, MFC-MRD has the potential to refine the current strategies of pedAML risk stratification, traditionally based on the cytogenetic and molecular genetic aberrations at diagnosis. Consequently, it may guide the modulation of therapy intensity and clinical decision making. However, the use of non-standardized protocols, including different staining panels, analysis, and gating strategies, may hamper a broad implementation of MFC-MRD monitoring in clinical routine. Besides, the thresholds of MRD positivity still need to be validated in large, prospective and multi-center clinical studies, as well as optimal time points of MRD assessment during therapy, to better discriminate patients with different prognosis. In the present review, we summarize the most relevant findings on MFC-MRD testing in pedAML. We examine the clinical significance of MFC-MRD and the recent advances in its standardization, including innovative approaches with an automated analysis of MFC-MRD data. We also touch upon other technologies for MRD assessment in AML, such as quantitative genomic breakpoint PCR, current challenges and future strategies to enable full incorporation of MFC-MRD into clinical practice.