The role of the primitive marker CD133 in CD34-negative acute myeloid leukemia for the detection of leukemia stem cells.

The most important reason for dismal outcomes in acute myeloid leukemia (AML) is the development of relapse. Leukemia stem cells (LSCs) are hypothesized to initiate relapse, and high CD34+CD38- LSC load is associated with poor prognosis. In 10% of AML patients, CD34 is not or is low expressed on the leukemic cells (<1%), and CD34+CD38- LSCs are absent. These patients are classified as CD34-negative. We aimed to determine whether the primitive marker CD133 can detect LSCs in CD34-negative AML. We retrospectively quantified 148 CD34-negative patients for proportions of CD34-CD133+ and CD133+CD38- cell fractions in the diagnostic samples of CD34-negative patients in the HOVON102 and HOVON132 trials. No prognostic difference was found between patients with high or low proportions of CD34-CD133+, which is found to be aberrantly expressed in AML. A high level of CD133+CD38- cells was not associated with poor overall survival, and expression in AML was similar to normal bone marrow. To conclude, CD133 is useful as an additional primitive marker for the detection of leukemic blast cells in CD34-negative AML. However, CD133+CD38 alone is not suitable for the detection of LSCs at diagnosis.

Impact of hemodilution on flow cytometry based measurable residual disease assessment in acute myeloid leukemia.

Measurable residual disease (MRD) measured in the bone marrow (BM) of acute myeloid leukemia (AML) patients after induction chemotherapy is an established prognostic factor. Hemodilution, stemming from peripheral blood (PB) mixing within BM during aspiration, can yield false-negative MRD results. We prospectively examined hemodilution by measuring MRD in BM aspirates obtained from three consecutive 2 mL pulls, along with PB samples. Our results demonstrated a significant decrease in MRD percentages between the first and second pulls (P = 0.025) and between the second and third pulls (P = 0.025), highlighting the impact of hemodilution. Initially, 39% of MRD levels (18/46 leukemia-associated immunophenotypes) exceeded the 0.1% cut-off, decreasing to 30% (14/46) in the third pull. Additionally, we assessed the performance of six published methods and parameters for distinguishing BM from PB samples, addressing or compensating for hemodilution. The most promising results relied on the percentages of CD16dim granulocytic population (scarce in BM) and CD117high mast cells (exclusive to BM). Our findings highlight the importance of estimating hemodilution in MRD assessment to qualify MRD results, particularly near the common 0.1% cut-off. To avoid false-negative results by hemodilution, it is essential to collect high-quality BM aspirations and preferably utilizing the initial pull for MRD testing.

Understanding differential technologies for detection of MRD and how to incorporate into clinical practice.

Patient- and leukemia-specific factors assessed at diagnosis classify patients with acute myeloid leukemia (AML) in risk categories that are prognostic for outcome. The induction phase with intensive chemotherapy in fit patients aims to reach a complete remission (CR) of less than 5% blasts in bone marrow by morphology. To deepen and sustain the response, induction is followed by consolidation treatment. This postremission treatment of patients with AML is graduated in intensity based on this favorable, intermediate, or adverse risk group classification as defined in the European Leukemia Network (ELN) 2022 recommendations. The increment of evidence that measurable residual disease (MRD) after induction can be superimposed on risk group at diagnosis is instrumental in tailoring further treatment accordingly. Several techniques are applied to detect MRD such as multiparameter flow cytometry (MFC), quantitative (digital) polymerase chain reaction (PCR), and next-generation sequencing. The clinical implementation of MRD and the technique used differ among institutes, leading to the accumulation of a wide range of data, and therefore harmonization is warranted. Currently, evidence for MRD guidance is limited to the time point after induction using MFC or quantitative PCR for NPM1 and core binding factor abnormalities in intermediate-risk patients. The role of MRD in targeted or nonintensive therapies needs to be clarified, although some data show improved survival in patients achieving CR-MRD negativity. Potential application of MRD for selection of conditioning before stem cell transplantation, monitoring after consolidation, and use as an intermediate end point in clinical trials need further evaluation.

Concordance in measurable residual disease result after first and second induction cycle in acute myeloid leukemia: An outcome- and cost-analysis.

Measurable residual disease (MRD) measured using multiparameter flow-cytometry (MFC) has proven to be an important prognostic biomarker in acute myeloid leukemia (AML). In addition, MRD is increasingly used to guide consolidation treatment towards a non-allogenic stem cell transplantation treatment for MRD-negative patients in the ELN-2017 intermediate risk group. Currently, measurement of MFC-MRD in bone marrow is used for clinical decision making after 2 cycles of induction chemotherapy. However, measurement after 1 cycle has also been shown to have prognostic value, so the optimal time point remains a question of debate. We assessed the independent prognostic value of MRD results at either time point and concordance between these for 273 AML patients treated within and according to the HOVON-SAKK 92, 102, 103 and 132 trials. Cumulative incidence of relapse, event free survival and overall survival were significantly better for MRD-negative (<0.1%) patients compared to MRD-positive patients after cycle 1 and cycle 2 (p ≤ 0.002, for all comparisons). A total of 196 patients (71.8%) were MRD-negative after cycle 1, of which the vast majority remained negative after cycle 2 (180 patients; 91.8%). In contrast, of the 77 MRD-positive patients after cycle 1, only 41 patients (53.2%) remained positive. A cost reduction of -€571,751 per 100 patients could be achieved by initiating the donor search based on the MRD-result after cycle 1. This equals to a 50.7% cost reduction compared to the current care strategy in which the donor search is initiated for all patients. These results show that MRD after cycle 1 has prognostic value and is highly concordant with MRD status after cycle 2. When MRD-MFC is used to guide consolidation treatment (allo vs non-allo) in intermediate risk patients, allogeneic donor search may be postponed or omitted after cycle 1. Since the majority of MRD-negative patients remain negative after cycle 2, this could safely reduce the number of allogeneic donor searches and reduce costs.

Technical Aspects of Flow Cytometry-based Measurable Residual Disease Quantification in Acute Myeloid Leukemia: Experience of the European LeukemiaNet MRD Working Party.

Measurable residual disease (MRD) quantified by multiparameter flow cytometry (MFC) is a strong and independent prognostic factor in acute myeloid leukemia (AML). However, several technical factors may affect the final read-out of the assay. Experts from the MRD Working Party of the European LeukemiaNet evaluated which aspects are crucial for accurate MFC-MRD measurement. Here, we report on the agreement, obtained via a combination of a cross-sectional questionnaire, live discussions, and a Delphi poll. The recommendations consist of several key issues from bone marrow sampling to final laboratory reporting to ensure quality and reproducibility of results. Furthermore, the experiences were tested by comparing two 8-color MRD panels in multiple laboratories. The results presented here underscore the feasibility and the utility of a harmonized theoretical and practical MFC-MRD assessment and are a next step toward further harmonization.

2021 Update on MRD in acute myeloid leukemia: a consensus document from the European LeukemiaNet MRD Working Party.

Measurable residual disease (MRD) is an important biomarker in acute myeloid leukemia (AML) that is used for prognostic, predictive, monitoring, and efficacy-response assessments. The European LeukemiaNet (ELN) MRD Working Party evaluated standardization and harmonization of MRD in an ongoing manner and has updated the 2018 ELN MRD recommendations based on significant developments in the field. New and revised recommendations were established during in-person and online meetings, and a 2-stage Delphi poll was conducted to optimize consensus. All recommendations are graded by levels of evidence and agreement. Major changes include technical specifications for next-generation sequencing-based MRD testing and integrative assessments of MRD irrespective of technology. Other topics include use of MRD as a prognostic and surrogate end point for drug testing; selection of the technique, material, and appropriate time points for MRD assessment; and clinical implications of MRD assessment. In addition to technical recommendations for flow- and molecular-MRD analysis, we provide MRD thresholds and define MRD response, and detail how MRD results should be reported and combined if several techniques are used. MRD assessment in AML is complex and clinically relevant, and standardized approaches to application, interpretation, technical conduct, and reporting are of critical importance.

Bimodal expression of potential drug target CLL-1 (CLEC12A) on CD34+ blasts of AML patients.

OBJECTIVES: This study aims to retrospectively assess C-lectin-like molecule 1 (CLL-1) bimodal expression on CD34+ blasts in acute myeloid leukemia (AML) patients (total N = 306) and explore potential CLL-1 bimodal associations with leukemia and patient-specific characteristics. METHODS: Flow cytometry assays were performed to assess the deeper immunophenotyping of CLL-1 bimodality. Cytogenetic analysis was performed to characterize the gene mutation on CLL-1-negative subpopulation of CLL-1 bimodal AML samples. RESULTS: The frequency of a bimodal pattern of CLL-1 expression of CD34+ blasts ranged from 8% to 65% in the different cohorts. Bimodal CLL-1 expression was most prevalent in patients with MDS-related AML (P = .011), ELN adverse risk (P = .002), NPM1 wild type (WT, P = .049), FLT3 WT (P = .035), and relatively low percentages of leukemia-associated immunophenotypes (P = .006). Additional immunophenotyping analysis revealed the CLL-1- subpopulation may consist of pre-B cells, immature myeloblasts, and hematopoietic stem cells. Furthermore, (pre)-leukemic mutations were detected in both CLL-1+ and CLL-1- subfractions of bimodal samples (N = 3). CONCLUSIONS: C-lectin-like molecule 1 bimodality occurs in about 25% of AML patients and the CLL-1- cell population still contains malignant cells, hence it may potentially limit the effectiveness of CLL-1-targeted therapies and warrant further investigation.

Measurable residual disease as a biomarker in acute myeloid leukemia: theoretical and practical considerations.

Several methodologies that rely on the detection of immunophenotypic or molecular abnormalities of the neoplastic cells are now available to quantify measurable ("minimal") residual disease (MRD) in acute myeloid leukemia (AML). Although the perfect MRD test does not (yet) exist, the strong association between MRD and adverse patient outcomes has provided the impetus to use measures of MRD as biomarker in the routine care of AML patients and during clinical trials. MRD test results may inform the selection of postremission therapy in some patients but evidence supporting the use of MRD as predictive biomarker is still limited. Several retrospective studies have shown that conversion from undetectable to detectable MRD or increasing MRD over time is associated with overt disease recurrence, and MRD testing may therefore be valuable as a monitoring biomarker for early detection of relapse. Interpreting serial MRD data is complex, with open questions regarding the optimal timing and frequency of testing, as well as the identification of test-specific thresholds to define relapse. Importantly, it is unknown whether intervening at the time of MRD detection, rather than at overt disease recurrence, improves outcomes. Finally, using MRD as a surrogate efficacy-response biomarker to accelerate drug development/approval has already been accepted by regulatory authorities in other diseases and is of great interest as a potential strategy in AML. While the prognostic value of MRD in AML is well established, data from prospective clinical trials confirming that treatment effects on MRD directly relate to clinical outcomes are needed to further establish the role of MRD as a surrogate endpoint in AML.

Quality of Life During Palliative Systemic Therapy for Esophagogastric Cancer: Systematic Review and Meta-Analysis.

BACKGROUND: Palliative systemic therapy can prolong life and reduce tumor-related symptoms for patients with advanced esophagogastric cancer. However, side effects of treatment could negatively affect health-related quality of life (HRQoL). Our aim was to review the literature and conduct a meta-analysis to examine the effect of palliative systemic therapy on HRQoL. METHODS: EMBASE, Medline, and Central were searched for phase II/III randomized controlled trials until April 2018 investigating palliative systemic therapy and HRQoL. Meta-analysis was performed on baseline and follow-up summary values of global health status (GHS) and other European Organisation for Research and Treatment of Cancer scales. A clinically relevant change and difference of 10 points (scale 0-100) was set to assess the course of HRQoL over time within treatment arms as well as between arms. RESULTS: We included 43 randomized controlled trials (N = 13 727 patients). In the first-line and beyond first-line treatment setting, pooled baseline GHS mean estimates were 54.6 (95% confidence interval = 51.9 to 57.3) and 57.9 (95% confidence interval = 55.7 to 60.1), respectively. Thirty-nine (81.3%) treatment arms showed a stable GHS over the course of time. Anthracycline-based triplets, fluoropyrimidine-based doublets without cisplatin, and the addition of trastuzumab to chemotherapy were found to have favorable HRQoL outcomes. HRQoL benefit was observed for taxane monotherapy and several targeted agents over best supportive care beyond first line. CONCLUSIONS: Patients reported impaired GHS at baseline and generally remained stable over time. Anthracycline-based triplets and fluoropyrimidine-based doublets without cisplatin may be preferable first-line treatment options regarding HRQoL for HER2-negative disease. Taxanes and targeted agents could provide HRQoL benefit beyond first line compared with best supportive care.

MRD Tailored Therapy in AML: What We Have Learned So Far.

Acute myeloid leukemia (AML) is a heterogeneous clonal disease associated with a dismal survival, partly due to the frequent occurrence of relapse. Many patient- and leukemia-specific characteristics, such as age, cytogenetics, mutations, and measurable residual disease (MRD) after intensive chemotherapy, have shown to be valuable prognostic factors. MRD has become a rich field of research where many advances have been made regarding technical, biological, and clinical aspects, which will be the topic of this review. Since many laboratories involved in AML diagnostics have experience in immunophenotyping, multiparameter flow cytometry (MFC) based MRD is currently the most commonly used method. Although molecular, quantitative PCR based techniques may be more sensitive, their disadvantage is that they can only be applied in a subset of patients harboring the genetic aberration. Next-generation sequencing can assess and quantify mutations in many genes but currently does not offer highly sensitive MRD measurements on a routine basis. In order to provide reliable MRD results, MRD assay optimization and standardization is essential. Different techniques for MRD assessment are being evaluated, and combinations of the methods have shown promising results for improving its prognostic value. In this regard, the load of leukemic stem cells (LSC) has also been shown to add to the prognostic value of MFC-MRD. At this moment, MRD after intensive chemotherapy is most often used as a prognostic factor to help stratify patients, but also to select the most appropriate consolidation therapy. For example, to guide post-remission treatment for intermediate-risk patients where MRD positive patients receive allogeneic stem cell transplantation and MRD negative receive autologous stem cell transplantation. Other upcoming uses of MRD that are being investigated include: selecting the type of allogeneic stem cell transplantation therapy (donor, conditioning), monitoring after stem cell transplantation (to allow intervention), and determining drug efficacy for the use of a surrogate endpoint in clinical trials.

TOXview: a novel graphical presentation of cancer treatment toxicity profiles.

Background: Toxicity profiles play a crucial role in the choice between specific palliative chemotherapy regimens. To optimize the quality of life for cancer patients, patients should be adequately informed about potential toxicities before undergoing chemotherapy. Therefore, we constructed TOXviews, a novel graphical presentation and overview of toxicity profiles to improve information provision about adverse events. As an example, we analyzed first-line chemotherapy regimens for advanced esophagogastric cancer (AEGC). Methods: We searched PubMed, EMBASE, CENTRAL, ASCO and ESMO for prospective phase II or III randomized controlled trials (RCTs) on palliative first-line systemic treatment for AEGC until February 2017. We extracted proportions of Common Terminology Criteria for Adverse Events grade 1-2 (mild) and 3-4 (severe) adverse events from each chemotherapy arm and pooled these by using single-arm meta-analysis. Toxicity profiles per chemotherapy regimen were visualized in bidirectional bar charts with pooled proportions plus 95% confidence intervals. For comparative analysis, chemotherapy regimens were grouped in singlets, doublets and triplets. Results: We included 92 RCTs with a total of 16,963 patients. TOXviews for 3 fluoropyrimidine singlets, 5 cisplatin-containing doublets (C-doublets), 10 fluoropyrimidine non-cisplatin containing doublets (F-doublets), 4 anthracycline-containing triplets (A-triplets) and 5 taxane-containing triplets (T-triplets) were constructed. C-doublets, A-triplets and T-triplets all showed an increased incidence of grade 3-4 adverse events and clinically relevant grade 1-2 adverse events compared to F-doublets. Conclusion: TOXview provides a new graphical presentation and overview of chemotherapy toxicities. TOXviews can be used to educate physicians about the incidences of AEs of systemic therapy and improve informed decision-making.

Capecitabine, 5-fluorouracil and S-1 based regimens for previously untreated advanced oesophagogastric cancer: A network meta-analysis.

As evidence is inconsistent and based on either isolated Asian or Western studies, we conducted a network meta-analysis (NMA) to examine efficacy and safety of 5-FU (5-fluorouracil), capecitabine and S-1-based first-line treatment of advanced esophagogastric cancer in Asian and Western patients. Medline, EMBASE, CENTRAL and conferences ASCO and ESMO were searched up to January 2016 for randomized-controlled-trials comparing 5-FU, capecitabine or S-1-based regimens with equal chemotherapy backbones. Direct and indirect data for overall survival (OS) and progression-free-survival (PFS) were combined on the Hazard Ratio (HR)-scale using random-effects NMA and calculated as combined HRs and 95%credible intervals (95%CrI). Grade 1-2 and grade 3-4 adverse events were compared with pair-wise meta-analysis. Fifteen studies were identified including capecitabine (n = 945), 5-FU (n = 2,132) or S-1 (n = 1,636). No differences were found in respectively OS and PFS for capecitabine-based versus 5-FU-based regimens (HR = 0.89, 95%CrI = 0.76-1.04 and HR = 0.98, 95%CrI = 0.75-1.32), S-1-based versus 5-FU-based regimens (HR = 0.92, 95%CrI = 0.82-1.04 and HR = 0.88, 95%CrI = 0.70-1.11) and S-1-based versus capecitabine-based regimens (HR = 1.03, 95%CrI = 0.87-1.22 and HR = 0.89, 95%CrI = 0.65-1.20). Effects were similar in Asian and Western subgroups. Toxicity profiles were different but a lower frequency of relevant adverse events was observed with S-1 In conclusion, as efficacy was similar, choosing fluoropyrimidines should be based on their individual toxicity profiles.

The Efficacy and Safety of First-line Chemotherapy in Advanced Esophagogastric Cancer: A Network Meta-analysis.

BACKGROUND: A globally accepted standard first-line chemotherapy regimen in advanced esophagogastric cancer (AEGC) is not clearly established. We conducted a systematic review to investigate the efficacy and safety of first-line chemotherapy using Network meta-analysis (NMA). METHODS: Medline, EMBASE, CENTRAL, and conferences were searched until June 2015 for randomized controlled trials that compared regimens containing: fluoropyrimidine (F), platinum (cisplatin [C] and oxaliplatin [Ox]), taxane (T), anthracycline (A), irinotecan (I), or methotrexate (M). Direct and indirect evidence for overall survival (OS) and progression-free-survival (PFS) were combined using random-effects NMA on the hazard ratio (HR) scale and calculated as combined hazard ratios and 95% credible intervals (CrIs). RESULTS: The NMA incorporated 17 chemotherapy regimens with 37 direct comparisons between regimens for OS (50 studies, n = 10 249) and 29 direct comparisons for PFS (34 studies, n = 7795). Combining direct and indirect effects showed increased efficacy for fluoropyrimidine noncisplatin doublets (F-doublets) over cisplatin doublets (C-doublets): FI vs CF (combined HR = 0.85, 95% CrI = 0.71 to 0.99), FOx vs CF (combined HR = 0.83, 95% CrI = 0.71 to 0.98) in OS and FOx vs CF (combined HR = 0.82, 95% CrI = 0.66 to 0.99) in PFS. Anthracycline-containing triplets (A-triplets: ACF, AFOx, AFM) and TCF triplet showed no benefit over F-doublets in OS and PFS. The triplet FOxT showed increased PFS vs F-doublets FT (combined HR = 0.61, 95% CrI = 0.38 to 0.99), FI (combined HR = 0.62, 95% CrI = 0.38 to 0.99), and FOx (combined HR = 0.67, 95% CrI = 0.44 to 0.99). Increased grade 3 to 4 toxicity was found for CF vs F-doublets, for ACF vs FI for TCF vs CF, and for FOxT vs FOx. CONCLUSIONS: Based on efficacy and toxicity, F-doublets FOx, FI, and FT are preferred as first-line treatment for AEGC compared with C-doublets, A-triplets, and TCF. FOxT is the most promising triplet.

Second- and third-line systemic therapy in patients with advanced esophagogastric cancer: a systematic review of the literature.

The optimal second- and third-line chemotherapy and targeted therapy for patients with advanced esophagogastric cancer is still a matter of debate. Therefore, a literature search was carried out in Medline, EMBASE, CENTRAL, and oncology conferences until January 2016 for randomized controlled trials that compared second- or third-line therapy. We included 28 studies with 4810 patients. Second-line, single-agent taxane/irinotecan showed increased survival compared to best supportive care (BSC) (hazard ratio 0.65, 95 % confidence interval 0.53-0.79). Median survival gain ranged from 1.4 to 2.7 months among individual studies. Taxane- and irinotecan-based regimens showed equal survival benefit. Doublet chemotherapy taxane/irinotecan plus platinum and fluoropyrimidine was not different in survival, but showed increased toxicity vs. taxane/irinotecan monotherapy. Compared to BSC, second-line ramucirumab and second- or third-line everolimus and regorafenib showed limited median survival gain ranging from 1.1 to 1.4 months, and progression-free survival gain, ranging from 0.3 to 1.6 months. Third- or later-line apatinib showed increased survival benefit over BSC (HR 0.50, 0.32-0.79). Median survival gain ranged from 1.8 to 2.3 months. Compared to taxane-alone, survival was superior for second-line ramucirumab plus taxane (HR 0.81, 0.68-0.96), and olaparib plus taxane (HR 0.56, 0.35-0.87), with median survival gains of 2.2 and 4.8 months respectively. Targeted agents, either in monotherapy or combined with chemotherapy showed increased toxicity compared to BSC and chemotherapy-alone. This review indicates that, given the survival benefit in a phase III study setting, ramucirumab plus taxane is the preferred second-line treatment. Taxane or irinotecan monotherapy are alternatives, although the absolute survival benefit was limited. In third-line setting, apatinib monotherapy is preferred.

The efficacy and safety of S-1-based regimens in the first-line treatment of advanced gastric cancer: a systematic review and meta-analysis.

BACKGROUND: S-1 is first-line therapy for advanced gastric cancer in Asia and is used with increased frequency in Western counties. We conducted a meta-analysis to investigate the efficacy and toxicity of S-1-based therapy compared with 5-fluorouracil (5-FU)/capecitabine-based therapy and S-1-based combination therapy compared with S-1 monotherapy. METHODS: MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, American Society of Clinical Oncology meeting abstracts, European Society for Medical Oncology meeting abstracts and ClinicalTrials.gov were searched for randomized clinical trials until May 2015. Data were extracted for overall survival (OS), progression-free-survival (PFS), objective response rate (ORR) and grade 1-2 and grade 3-4 adverse events. Stratified OS data for subgroups were extracted. RESULTS: S-1 was not different from 5-FU (eight studies, n = 2788) in terms of OS [hazard ratio (HR) 0.93, 95 % confidence interval (CI) 0.85-1.01] and PFS (HR 0.87, 95 % CI 0.73-1.04), whereas ORR was higher (risk ratio 1.43, 95 % CI 1.05-1.96). There was no subgroup difference in efficacy among Asian and Western patients, but in Western patients S-1 was associated with a lower rate of febrile neutropenia, toxicity-related deaths and grade 3-4 stomatitis and mucositis compared with 5-FU. S-1 showed no difference in efficacy compared with capecitabine (three studies, n = 329), but was associated with a lower rate of grade 3-4 neutropenia and grade 1-2 hand-foot syndrome. S-1-combination therapy was superior to S-1 monotherapy (eight studies, n = 1808) in terms of OS (HR 0.76, 95 % CI 0.65-0.90), PFS (HR 0.68, 95 % CI 0.56-0.82) and ORR (risk ratio 1.20, 95 % CI 1.04-1.38) but was more toxic. Survival benefit of S-1 combination therapy over S-1 monotherapy was most pronounced in patients with non-measurable disease, diffuse-type histological features and peritoneal metastasis. CONCLUSIONS: S-1 is effective and tolerable as first-line therapy for advanced gastric cancer in both Asian and Western countries.