Prognosis in Chronic Myeloid Leukemia: Baseline Factors, Dynamic Risk Assessment and Novel Insights.

The introduction of tyrosine kinase inhibitors (TKIs) has changed the treatment paradigm of chronic myeloid leukemia (CML), leading to a dramatic improvement of the outcome of CML patients, who now have a nearly normal life expectancy and, in some selected cases, the possibility of aiming for the more ambitious goal of treatment-free remission (TFR). However, the minority of patients who fail treatment and progress from chronic phase (CP) to accelerated phase (AP) and blast phase (BP) still have a relatively poor prognosis. The identification of predictive elements enabling a prompt recognition of patients at higher risk of progression still remains among the priorities in the field of CML management. Currently, the baseline risk is assessed using simple clinical and hematologic parameters, other than evaluating the presence of additional chromosomal abnormalities (ACAs), especially those at "high-risk". Beyond the onset, a re-evaluation of the risk status is mandatory, monitoring the response to TKI treatment. Moreover, novel critical insights are emerging into the role of genomic factors, present at diagnosis or evolving on therapy. This review presents the current knowledge regarding prognostic factors in CML and their potential role for an improved risk classification and a subsequent enhancement of therapeutic decisions and disease management.

The EMA Assessment of Asciminib for the Treatment of Adult Patients With Philadelphia Chromosome-Positive Chronic Myeloid Leukemia in Chronic Phase Who Were Previously Treated With at Least Two Tyrosine Kinase Inhibitors.

Asciminib is an allosteric high-affinity tyrosine kinase inhibitor (TKI) of the BCR-ABL1 protein kinase. This kinase is translated from the Philadelphia chromosome in chronic myeloid leukemia (CML). Marketing authorization for asciminib was granted on August 25, 2022 by the European Commission. The approved indication was for patients with Philadelphia chromosome-positive CML in the chronic phase which have previously been treated with at least 2 TKIs. Clinical efficacy and safety of asciminib were evaluated in the open-label, randomized, phase III ASCEMBL study. The primary endpoint of this trial was major molecular response (MMR) rate at 24 weeks. A significant difference in MRR rate was shown between the asciminib treated population and the bosutinib control group (25.5% vs. 13.2%, respectively, P = .029). In the asciminib cohort, adverse reactions of at least grade 3 with an incidence ≥ 5% were thrombocytopenia, neutropenia, increased pancreatic enzymes, hypertension, and anemia. The aim of this article is to summarize the scientific review of the application which led to the positive opinion by the European Medicines Agency's Committee for Medicinal Products for Human Use.

Assessment of regulatory T cells (Tregs) and Foxp3 methylation level in chronic myeloid leukemia patients on tyrosine kinase inhibitor therapy.

The key cell population permits cancer cells to avoid immune-surveillance is regulatory T cells (Tregs). This study evaluates the level of Tregs in chronic myeloid leukemia (CML) patients and the effect of Tyrosine kinase inhibitor (TKI) on Treg levels, as a pathway to understand the immune response and behavior among advance stage and optimal response CML patients using imatinib therapy. Blood samples were collected from 30 CML patients (optimal response to TKI), 30 CML patients (failure response to TKI), and 30 age- and gender-matched controls. Analysis involved measuring percentages of Tregs (CD4 + CD25 + FOXP3 +) by flow cytometer and demethylation levels of FOXP3 Treg-specific demethylated region (TSDR) by PCR. The data revealed that Tregs and the FOXP3-TSDR demethylation percentages significantly increased in failure response group in comparison to the optimal response and control groups, while no significant difference between optimal response and control groups. Tregs and FOXP3 TSDR demethylation percentages showed high sensitivity and specificity, suggesting powerful discriminatory biomarkers between failure and optimal groups. An assessment of the Tregs and demethylation percentage among different BCR-ABL levels of CML patients on TKI revealed no significant differences in parameter percentage in the optimal response to TKI patients with different molecular responses (log 3 reduction or other deeper log 4.5 and 5 reduction levels). Our findings demonstrate an effective role of functional Tregs among different CML stages. Also, the study suggests that the major molecular response to therapy at level 0.1% of BCR-ABL transcript could be enough to induce immune system restoration in patients.

Assessment of quantitative polymerase chain reaction for BCR-ABL1 transcripts in chronic myeloid leukaemia: Are improved outcomes in patients with e14a2 transcripts an artefact of technology?

The clinical outcome of chronic myeloid leukaemia patients has vastly improved since the introduction of tyrosine kinase inhibitor treatment, with a significant proportion of patients able to achieve treatment-free remission. However, studies have shown that patients with the e13a2 transcript were less likely to achieve major molecular response compared to those with e14a2 transcripts. Most quantitative polymerase chain reaction (PCR) assays for detection of the BCR-ABL1 fusion gene do not differentiate between the two transcripts and we therefore hypothesised that technical bias linked to the qPCR assay could partially explain the discrepancy in outcomes. We designed an e14a2-specific assay and identified no difference in results compared to an e13a2 standard assay. We then demonstrated that the commercial e14a2 standards were causing a significant overestimation of the e13a2 transcripts. Finally, we reviewed patient management after the qPCR values were corrected, using our new evaluation. We concluded that despite statistically significant differences in qPCR results, there was no impact on patient management or outcome. We conclude that, at least in our institution, it would be inappropriate to perform separate assays for patients with e13a2 or e14a2.

Integrating genetic and epigenetic factors in chronic myeloid leukemia risk assessment: toward gene expression-based biomarkers.

Cancer treatment is constantly evolving from a one-size-fits-all towards bespoke approaches for each patient. In certain solid cancers, including breast and lung, tumor genome profiling has been incorporated into therapeutic decision-making. For chronic phase chronic myeloid leukemia (CML), while tyrosine kinase inhibitor therapy is the standard treatment, current clinical scoring systems cannot accurately predict the heterogeneous treatment outcomes observed in patients. Biomarkers capable of segregating patients according to outcome at diagnosis are needed to improve management, and facilitate enrollment in clinical trials seeking to prevent blast crisis transformation and improve the depth of molecular responses. To this end, gene expression (GE) profiling studies have evaluated whether GE signatures at diagnosis are clinically informative. Patient material from a variety of sources has been profiled using microarrays, RNA sequencing and, more recently, single-cell RNA sequencing. However, differences in the cell types profiled, the technologies used, and the inherent complexities associated with the interpretation of genomic data pose challenges in distilling GE datasets into biomarkers with clinical utility. The goal of this paper is to review previous studies evaluating GE profiling in CML, and explore their potential as risk assessment tools for individualized CML treatment. We also review the contribution that acquired mutations, including those seen in clonal hematopoiesis, make to GE profiles, and how a model integrating contributions of genetic and epigenetic factors in resistance to tyrosine kinase inhibitors and blast crisis transformation can define a route to GE-based biomarkers. Finally, we outline a four-stage approach for the development of GE-based biomarkers in CML.

Comparison of 3-month cytogenetic and molecular assays for early assessment of long-term clinical impact after BCR-ABL1 tyrosine kinase inhibitor treatment in chronic myeloid leukemia.

To compare the clinical significance of 3-month cytogenetic and molecular monitoring, we analyzed 1,410 paired cytogenetic and molecular data from 705 chronic-phase chronic myeloid leukemia patients. Based on early cytogenetic response (ECyR, Ph+≤35 %) and molecular response (EMR, BCR-ABL1IS≤10 %) at 3 months, the patients were divided into four groups (group 1: ECyR + EMR, n = 560; group 2: no ECyR + EMR, n = 27; group 3: ECyR + no EMR, n = 55; group 4: no ECyR + no EMR, n = 63). By 10 years, major molecular response (MMR), deep molecular response (MR4.5), overall survival (OS), and progression-free survival (PFS) rates were significantly high in group 1 (P < 0.001). Comparing groups 2 and 3, the MMR (P = 0.096), MR4.5 (P = 0.945), OS (P = 0.832), and PFS (P = 0.627) rates tended to be higher in group 2, although not significantly. Thus, the cytogenetic assay can not only be useful but its addition may also provide a more precise prediction of MR4.5.

Use of the «BCR/ABL - multitest¼ kit in the algorithm of laboratory diagnostics of oncohematological diseases: economic aspects.

Abnormal mRNAs of the hybrid BCR-ABL gene in the majority of cases initiate the synthesis of proteins with a mass of 210 kDa (p210), 190 kDa (p190), and 230 kDa (p230). Expression of the p210 variant is most common in CML (95% of cases), while the p190 and p230 variants are less common (1-4%). On the contrary, p190 predominates in ALL. Measurement of BCR/ABL gene expression is included in clinical guidelines for the diagnosis of CML and ALL as sequential tests in accordance with their occurrence. At the same time, in the context of primary patients testing with suspected hematological malignancies with a low prevalence of BCR-ABL positive patients in the cohort of examined individuals, sequential testing is associated with low cost-effectiveness. Purpose: approbation of a parallel algorithm for detecting all three (p210, p190 and p230) using the multiplex RT-PCR format implemented in the «BCR/ABL-MULTITEST¼ reagent kit. We used anonymized blood samples from patients with suspected CML, as well as samples from ALL patients before starting therapy. Testing of blood samples was carried out using two variants of the algorithm: sequential determination of individual BCR-ABL transcripts and parallel determination using the developed set of reagents «BCR/ABL-MULTITEST¼. To detect the p210 transcript, a commercial kit «AmpliSens® Leukemia Quantum M-bcr-FRT¼ (Central Research Institute of Epidemiology of Rospotrebnadzor, Russia) was used. Simultaneously, a test was used to detect all three variants of BCR-ABL transcripts using the «BCR/ABL - MULTITEST¼ reagent kit based on a monochrome multiplex reaction «in one test tube¼. Reverse transcription were carried out using the REVERTA-L reagent kit (Central Research Institute of Epidemiology of Rospotrebnadzor, Russia) in accordance with the manufacturer's instructions. Using the reagent kits «BCR/ABL-MULTITEST¼ and «AmpliSens® Leukemia Quantum M-bcr-FRT¼ there is a high level of correlation of quantitative results of determining the chimeric transcript BCR-ABL р210 (r = 0.99). When using the proposed parallel algorithm with the primary use of the «BCR/ABL-MULTITEST¼ reagent kit, out of 95 patients with suspected CML, 9 samples with p210 transcript were identified, one with p190 BCR / ABL, and in one case a transcript variant characteristic of chronic neutrophilic leukemia - p230 BCR / ABL. The estimated cost for detecting one positive case of BCR-ABL when using the parallel diagnostic algorithm «BCR/ABL-MULTITEST¼ with a focused flow of studies is reduced by about 2 times due to a decrease in the amount of laboratory plastic used and the volume of the reaction mixture, as well as the absence of the need for repeated separate tests to detect p190 and p230. The use of the multiplex PCR-RT test system «BCR/ABL-MULTITEST¼ allows detecting in one test tube all three main variants of BCR-ABL transcripts - p210, p190, p230 and achieving significant resource savings when examining a cohort of patients with suspected CML and ALL and low frequency of positive samples.

Assessment of individual molecular response in chronic myeloid leukemia patients with atypical BCR-ABL1 fusion transcripts: recommendations by the EUTOS cooperative network.

PURPOSE: Approximately 1-2% of chronic myeloid leukemia (CML) patients harbor atypical BCR-ABL1 transcripts that cannot be monitored by real-time quantitative PCR (RT-qPCR) using standard methodologies. Within the European Treatment and Outcome Study (EUTOS) for CML we established and validated robust RT-qPCR methods for these patients. METHODS: BCR-ABL1 transcripts were amplified and sequenced to characterize the underlying fusion. Residual disease monitoring was carried out by RT-qPCR with specific primers and probes using serial dilutions of appropriate BCR-ABL1 and GUSB plasmid DNA calibrators. Results were expressed as log reduction of the BCR-ABL1/GUSB ratio relative to the patient-specific baseline value and evaluated as an individual molecular response (IMR). RESULTS: In total, 330 blood samples (2-34 per patient, median 8) from 33 CML patients (19 male, median age 62 years) were analyzed. Patients expressed seven different atypical BCR-ABL1 transcripts (e1a2, n = 6; e6a2, n = 1; e8a2, n = 2; e13a3, n = 4; e14a3, n = 6; e13a3/e14a3, n = 2; e19a2, n = 12). Most patients (61%) responded well to TKI therapy and achieved an IMR of at least one log reduction 3 months after diagnosis. Four patients relapsed with a significant increase of BCR-ABL1/GUSB ratios. CONCLUSIONS: Characterization of atypical BCR-ABL1 transcripts is essential for adequate patient monitoring and to avoid false-negative results. The results cannot be expressed on the International Scale (IS) and thus the common molecular milestones and guidelines for treatment are difficult to apply. We, therefore, suggest reporting IMR levels in these cases as a time-dependent log reduction of BCR-ABL1 transcript levels compared to baseline prior to therapy.

Assessment of Outcomes After Stopping Tyrosine Kinase Inhibitors Among Patients With Chronic Myeloid Leukemia: A Nonrandomized Clinical Trial.

IMPORTANCE: Tyrosine kinase inhibitors (TKIs) have been associated with improved survival of patients with chronic myeloid leukemia (CML) but are also associated with adverse effects, especially fatigue and diarrhea. Discontinuation of TKIs is safe and is associated with the successful achievement of treatment-free remission (TFR) for some patients. OBJECTIVE: To evaluate molecular recurrence (MRec) and patient-reported outcomes (PROs) after TKI discontinuation for US patients with CML. DESIGN, SETTING, AND PARTICIPANTS: The Life After Stopping TKIs (LAST) study was a prospective single-group nonrandomized clinical trial that enrolled 172 patients from 14 US academic medical centers from December 18, 2014, to December 12, 2016, with a minimum follow-up of 3 years. Participants were adults with chronic-phase CML whose disease was well controlled with imatinib, dasatinib, nilotinib, or bosutinib. Statistical analysis was performed from August 13, 2019, to March 23, 2020. INTERVENTION: Discontinuation of TKIs. MAIN OUTCOMES AND MEASURES: Molecular recurrence, defined as loss of major molecular response (BCR-ABL1 International Scale ratio >0.1%) by central laboratory testing, and PROs (Patient-Reported Outcomes Measurement Information System computerized adaptive tests) were monitored. Droplet digital polymerase chain reaction (ddPCR) was performed on samples with undetectable BCR-ABL1 by standard real-time quantitative polymerase chain reaction (RQ-PCR). RESULTS: Of 172 patients, 89 were women (51.7%), and the median age was 60 years (range, 21-86 years). Of 171 patients evaluable for molecular analysis, 112 (65.5%) stayed in major molecular response, and 104 (60.8%) achieved TFR. Undetectable BCR-ABL1 by either ddPCR or RQ-PCR at the time of TKI discontinuation (hazard ratio, 3.60; 95% CI, 1.99-6.50; P < .001) and at 3 months (hazard ratio, 5.86; 95% CI, 3.07-11.1; P < .001) was independently associated with MRec. Molecular recurrence for patients with detectable BCR-ABL1 by RQ-PCR was 50.0% (14 of 28), undetectable BCR-ABL1 by RQ-PCR but detectable by ddPCR was 64.3% (36 of 56), and undetectable BCR-ABL1 by both ddPCR and RQ-PCR was 10.3% (9 of 87) (P ≤ .001). Of the 112 patients in TFR at 12 months, 90 (80.4%) had a clinically meaningful improvement in fatigue, 39 (34.8%) had a clinically meaningful improvement in depression, 98 (87.5%) had a clinically meaningful improvement in diarrhea, 24 (21.4%) had a clinically meaningful improvement in sleep disturbance, and 5 (4.5%) had a clinically meaningful improvement in pain interference. Restarting a TKI resulted in worsening of PROs. CONCLUSIONS AND RELEVANCE: In this study, TKI discontinuation was safe, and 60.8% of patients remained in TFR. Discontinuation of TKIs was associated with improvements in PROs. These findings should assist patients and physicians in their decision-making regarding discontinuation of TKIs. Detectable BCR-ABL1 by RQ-PCR or ddPCR at the time of TKI discontinuation was associated with higher risk of MRec; clinical application of this finding should be confirmed in other studies. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02269267.

Molecular testing of chronic myeloid leukaemia in low resource areas.

Most cancer cases occur in areas of low resources. The diagnosis, treatment and monitoring of cancers is especially challenging in these locations. Unique partnerships exist between non-profit organisations and pharmaceutical companies to provide free drugs to CML patients throughout the world if the diagnosis can be rigorously and unambiguously established. But there lies the rub: How do you perform molecular diagnostics in areas where even electricity is unreliable? Here we describe the evolution of testing patients from low resource areas, which, when merged with a remarkable effort to bring tyrosine kinase inhibitors to patients across the globe, have led to survival outcomes similar to cases in industrialised countries.

Investigating the cytotoxic and apoptotic effects of sunitinib upon K-562 chronic myelogenous leukemia cell line and assessment of gene profiling.

OBJECTIVE: Tyrosine kinase inhibitors (TKIs) which efficiently inhibit BCR-ABL are highly effective for clinical treatment of chronic myeloid leukemia (CML), but development of resistance to TKIs is a big challenge to treatment. Sunitinib is a multitargeted TKI targeting vascular endothelial growth factor receptor and is defined a safe and effective candidate target, but its effect on other signaling pathways is unknown. To investigate the cytotoxic and apoptotic effect of sunitinib in CML cell model K-562 on JAK-STAT signaling pathway components, suppressor genes and oncogenes, hematopoiesis-related genes, cell cycle and VEGF pathway components, and mRNA level expression changes was aimed. MATERIALS AND METHODS: Sunitinib's effective dose cytotoxic IC50 was determined by trypan blue and WST-1 cell proliferation assay tests. Expression levels of target genes were determined by quantitative reverse transcriptase polymerase chain reaction simultaneously after sunitinib application. Protein expression analysis was determined by "WesternBreeze Chromogenic Kit-Anti-Rabbit" based on the principles of the application kit by Western blot analysis. RESULTS: Assessing the cytotoxicity of K-562 cells following sunitinib treatment revealed that sunitinib decreased cell proliferation in a time- and dose-dependent manner. According to the sunitinib inhibition curve, IC50 dose was calculated as 3.5 µM at 48th h for K-562 cells and apoptosis assays pointed that sunitinib induces apoptotic cell death of leukemic cells at moderate levels. CONCLUSION: Our study supports that sunitinib might be used as a novel therapeutic target to trigger apoptosis in CML cells which in turn might accelerate therapeutic response in regard to inhibiting oncogenes and enhancing tumor suppressors in cooperation with cell cycle regulatory genes.

Comparison of BCR-ABL1 quantification in peripheral blood and bone marrow using an International Scale-standardized assay for assessment of deep molecular response in chronic myeloid leukemia.

Background Monitoring of molecular response (MR) using quantitative polymerase chain reaction (PCR) for BCR-ABL1 is a pivotal tool for guiding tyrosine kinase inhibitor therapy and the long-term follow-up of patients with chronic myeloid leukemia (CML). Results of MR monitoring are standardized according to the International Scale (IS), and specific time-dependent molecular milestones for definition of optimal response and treatment failure have been included in treatment recommendations. The common practice to use peripheral blood (PB) instead of bone marrow (BM) aspirate to monitor the MR monitoring in CML has been questioned. Some studies described differences between BCR-ABL1 levels in paired PB and BM specimens. Methods We examined 631 paired PB and BM samples from 283 CML patients in a retrospective single-center study using an IS normalized quantitative reverse transcription (qRT)-PCR assay for quantification of BCR-ABL1IS. Results A good overall concordance of BCR-ABL1IS results was found, a systematic tendency towards higher BCR-ABL1IS levels in PB was observed in samples of CML patients in a major MR. This difference was most pronounced in patients treated with imatinib for at least 1 year. Importantly, the difference resulted in a significantly lower rate of deep MR when BCR-ABL1IS was assessed in the PB compared to BM aspirates. Conclusions In summary, our data suggest that the classification of deep MR in patients with CML is more stringent in PB than in BM. Our study supports the current practice to primarily use PB for long-term molecular follow-up monitoring in CML.

Prospective assessment of NGS-detectable mutations in CML patients with nonoptimal response: the NEXT-in-CML study.

In chronic myeloid leukemia (CML) patients, tyrosine kinase inhibitors (TKIs) may select for drug-resistant BCR-ABL1 kinase domain (KD) mutants. Although Sanger sequencing (SS) is considered the gold standard for BCR-ABL1 KD mutation screening, next-generation sequencing (NGS) has recently been assessed in retrospective studies. We conducted a prospective, multicenter study (NEXT-in-CML) to assess the frequency and clinical relevance of low-level mutations and the feasibility, cost, and turnaround times of NGS-based BCR-ABL1 mutation screening in a routine setting. A series of 236 consecutive CML patients with failure (n = 124) or warning (n = 112) response to TKI therapy were analyzed in parallel by SS and NGS in 1 of 4 reference laboratories. Fifty-one patients (22 failure, 29 warning) who were negative for mutations by SS had low-level mutations detectable by NGS. Moreover, 29 (27 failure, 2 warning) of 60 patients who were positive for mutations by SS showed additional low-level mutations. Thus, mutations undetectable by SS were identified in 80 out of 236 patients (34%), of whom 42 (18% of the total) had low-level mutations somehow relevant for clinical decision making. Prospective monitoring of mutation kinetics demonstrated that TKI-resistant low-level mutations are invariably selected if the patients are not switched to another TKI or if they are switched to a inappropriate TKI or TKI dose. The NEXT-in-CML study provides for the first time robust demonstration of the clinical relevance of low-level mutations, supporting the incorporation of NGS-based BCR-ABL1 KD mutation screening results in the clinical decision algorithms.

Cost effectiveness of therapeutic drug monitoring for imatinib administration in chronic myeloid leukemia.

BACKGROUND: Imatinib mesylate (IM) is a first-line treatment option for patients with chronic myeloid leukemia (CML). Patients who fail or are intolerant to IM therapy are treated with more expensive second and third-generation tyrosine kinase inhibitors. Patients show wide variation in trough concentrations in response to standard dosing. Thus, many patients receive subtherapeutic or supratherapeutic doses. Therapeutic drug monitoring (TDM) may improve dose management that, in turn, may reduce costs and improve outcomes. However, TDM also adds to the cost of patient care. The objective of this study was to determine the cost-effectiveness of TDM for generic IM therapy. METHODS: We developed a microsimulation model for the trough plasma concentration of IM which is related to a cytogenetic or molecular response. We compared two cohorts: one with TDM and one without TDM (NTDM). The lifetime incremental cost-effectiveness ratio (ICER) was calculated using quality-adjusted life years (QALYs) as the effectiveness measure. One-way and probabilistic sensitivity analyses were performed. RESULTS: The lifetime cost and QALY of treatment with TDM were $2,137K [95% Ci: 2,079K; 2,174K] and 12.37 [95% CI: 12.07; 12.55], respectively. The cost and QALY of NTDM were $2,132K [95% CI: 2,091K; 2,197K] and 12.23 [95% CI: 11.96; 12.50], respectively. The incremental cost and QALY for TDM relative to NTDM was $4,417 [95% CI: -52,582; 32,097]) and 0.15 [95% CI: -0.13; 0.28]. The ICER for TDM relative to NTDM was $30,450/QALY. Probabilistic sensitivity analysis showed that TDM was cost-effective relative to NTDM in 90% of the tested scenarios at a willingness-to-pay threshold of $100,000/QALY. CONCLUSIONS: Although the impact of TDM is modest, the cost-effectiveness over a lifetime horizon (societal perspective, ($30,450/QALY) falls within the acceptable range (< $100k/QALY).

Laying the foundation for genomically-based risk assessment in chronic myeloid leukemia.

Outcomes for patients with chronic myeloid leukemia (CML) have substantially improved due to advances in drug development and rational treatment intervention strategies. Despite these significant advances there are still unanswered questions on patient management regarding how to more reliably predict treatment failure at the time of diagnosis and how to select frontline tyrosine kinase inhibitor (TKI) therapy for optimal outcome. The BCR-ABL1 transcript level at diagnosis has no established prognostic impact and cannot guide frontline TKI selection. BCR-ABL1 mutations are detected in ~50% of TKI resistant patients but are rarely responsible for primary resistance. Other resistance mechanisms are largely uncharacterized and there are no other routine molecular testing strategies to facilitate the evaluation and further stratification of TKI resistance. Advances in next-generation sequencing technology has aided the management of a growing number of other malignancies, enabling the incorporation of somatic mutation profiles in diagnosis, classification, and prognostication. A largely unexplored area in CML research is whether expanded genomic analysis at diagnosis, resistance, and disease transformation can enhance patient management decisions, as has occurred for other cancers. The aim of this article is to review publications that reported mutated cancer-associated genes in CML patients at various disease phases. We discuss the frequency and type of such variants at initial diagnosis and at the time of treatment failure and transformation. Current limitations in the evaluation of mutants and recommendations for future reporting are outlined. The collective evaluation of mutational studies over more than a decade suggests a limited set of cancer-associated genes are indeed recurrently mutated in CML and some at a relatively high frequency. Genomic studies have the potential to lay the foundation for improved diagnostic risk classification according to clinical and genomic risk, and to enable more precise early identification of TKI resistance.

Using healthcare claims data to analyze the prevalence of BCR-ABL-positive chronic myeloid leukemia in France: A nationwide population-based study.

BACKGROUND: Data on Chronic Myeloid Leukemia (CML) prevalence are scarce. Here we provide an estimation of the prevalence of CML in France for the year 2014 using French national health insurance data. METHODS: We selected patients claiming reimbursement for tyrosine kinase inhibitors (TKI) or with hospital discharge diagnoses for CML, BCR/ABL-positive or with full reimbursement of health care expenses for myeloid leukemia. We built an algorithm which we validated on a random sample of 100 potential CML patients by comparing the results obtained using the algorithm and the opinion of two hematologists who reviewed the patient demographics and sequence of care abstracted from claims data (internal validity). For external validity, we compared the number of incident CML patients identified using the algorithm with those recorded in French population-based cancer registries in departments covered by such a registry. RESULTS: We identified 10 789 prevalent CML patients in 2014, corresponding to a crude prevalence rate of 16.3 per 100 000 inhabitants [95% confidence interval (CI) 16.0-16.6]: 18.5 in men [18.0-19.0] and 14.2 in women [13.8-14.6]. The crude CML prevalence was less than 1.6 per 100 000 [1.2-2.0] under age 20, increasing to a maximum of 48.2 [45.4-51.2) at ages 75-79. It varied from 10.2 to 23.8 per 100 000 across French departments. The algorithm showed high internal and external validity. Concordance rate between the algorithm and the hematologists was 96%, and the numbers of incident CML patients identified using the algorithm and the registries were 162 and 150, respectively. CONCLUSION: We built and validated an algorithm to identify CML patients in administrative healthcare databases. In addition to prevalence estimation, the algorithm could be used for future economic evaluations or pharmaco-epidemiological studies in this population.

Results of the European survey on the assessment of deep molecular response in chronic phase CML patients during tyrosine kinase inhibitor therapy (EUREKA registry).

PURPOSE: The advent of tyrosine kinase inhibitor (TKI) therapies has revolutionized the treatment of chronic myeloid leukemia (CML). The European LeukemiaNet (ELN) recommends quantification of BCR-ABL1 transcripts by real-time quantitative PCR every 3 months during TKI treatment. Since a proportion of patients in deep molecular response (DMR: MR4, MR4.5, MR5) maintain remission after treatment stop, assessment of DMR is crucial. However, systematically collected molecular data, monitored with sensitive standardized assays, are not available outside clinical trials. METHODS: Data were collected on the standardized assessment of molecular response in the context of real-life practice. BCR-ABL1 transcript levels after > 2 years of TKI therapy were evaluated for DMR by local laboratories as well as standardized EUTOS laboratories. Since standardized molecular monitoring is a prerequisite for treatment discontinuation, central surveillance of the performance of the participating laboratories was carried out. RESULTS: Between 2014 and 2017, 3377 peripheral blood samples from 1117 CML patients were shipped to 11 standardized reference laboratories in six European countries. BCR-ABL1 transcript types were b3a2 (41.63%), b2a2 (29.99%), b2a2/b3a2 (3.58%) and atypical (0.54%). For 23.72% of the patients, the initial transcript type had not been reported. Response levels (EUTOS laboratory) were: no MMR, n = 197 (6.51%); MMR, n = 496 (16.40%); MR4, n = 685 (22.64%); MR4.5, n = 937 (30.98%); MR5, n = 710 (23.47%). With a Cohen's kappa coefficient of 0.708, a substantial agreement between EUTOS-certified and local laboratories was shown. CONCLUSIONS: Multicenter DMR assessment is feasible in the context of real-life clinical practice in Europe. Information on the BCR-ABL1 transcript type at diagnosis is crucial to accurately monitor patients' molecular response during or after TKI therapy.

Using the EPIDEM Model of Quality Improvement to Increase Value of BCR-ABL1 Tests.

Objectives: As pathologists and laboratorians, we can enhance patient care by promoting the appropriate ordering of diagnostic tests. Our goal was to improve the ordering of BCR-ABL1 tests by using the EPIDEM model of quality improvement. Methods: We applied the EPIDEM model, which emphasizes understanding local context, culture, and resources, to explore inappropriate BCR-ABL1 ordering, promote and implement a new reflexive testing strategy in-house, document and evaluate effectiveness, and make stepwise modifications. Results: Multiple quality improvement interventions correlated with cost savings and decreased total errors and incorrect orders for both BCR-ABL1 major and minor positive patients. Furthermore, our laboratory built stronger collaborative relationships with colleagues within and outside of pathology. Conclusions: Our molecular pathology laboratory successfully used the EPIDEM model of quality improvement to improve the ordering of BCR-ABL1 tests and promote better patient care by focusing on educational efforts and modification of laboratory workflow.

Real-time quantitative PCR: a reliable molecular diagnostic and follow-up tool for 'minimal residual disease' assessment in chronic myeloid leukemia.

Molecular monitoring of BCR-ABL transcript levels by real-time quantitative PCR is increasingly being used to diagnose the disease and assess treatment response in patients with chronic myeloid leukemia (CML). This has become particularly relevant when residual levels of leukemia usually fall below the level of detection by cytogenetic analysis. Forty-two CML patients, including 18 males (42.86%) and 24 females (57.14%) aged 7-75 years, were enlisted for the study and followed-up for the response to imatinib treatment. Patients were subjected to Multiplex RT-PCR (reverse-transcriptase PCR) and were all found to harbor either e13a2 or the e14a2, which could be analyzed by a single Taqman probe based quantitation kit (Geno-Sen's) to quantitate the BCR-ABL transcript load. The Multiplex RT-PCR and peripheral blood cytogenetics providing specific and sensitive detection of BCR-ABL fusion transcripts and metaphase signal load respectively were used as parallel reference tools to authenticate the q-PCR findings. There was 100% concordance between the multiplex RT-PCR and the q-PCR as every positive RT-PCR assay for a transcript reflected as q-PCR load of above 0% for that transcript. q-PCR also demonstrated a strong Pearson correlation with the cytogenetic response.

Impact of Genetic Mutations and Health Plan Access to Therapies on Treatment Response and Drug Costs Related to Tyrosine Kinase Inhibitor Treatment Among Patients With Chronic Myelogenous Leukemia.

OBJECTIVES: This study assessed treatment responses and economic consequences of limiting access to the second-generation BCR-ABL1 tyrosine kinase inhibitors (2G-TKI), dasatinib and nilotinib, for treatment of chronic myelogenous leukemia, while taking into account frequencies of genetic mutations that exhibit different sensitivities to the 2G-TKIs. METHODS: Frequencies of BCR-ABL1 mutations and the impact of mutations on responses to 2G-TKIs were obtained from published literature and used as inputs in a decision analytics model. Complete hematologic response (CHR) and major cytogenetic response (MCyR) were estimated after 12 months of 2G-TKI treatment. Total annual 2G-TKI drug costs per CHR and MCyR were estimated and compared among 3 2G-TKI access scenarios: (1) open access to both 2G-TKIs; (2) access restricted to dasatinib (DASA-only); and (3) access restricted to nilotinib (NILO-only). RESULTS: Among a hypothetical cohort of 1000 2G-TKI-treated chronic myelogenous leukemia patients, the percentage of patients with CHR and MCyR were greatest for the open access plan (CHR: 93%, MCyR: 56%), followed by DASA-only (88%, 53%) and NILO-only (67%, 47%). Compared with the 2G-TKI costs per CHR in open access ($120,706/CHR), the costs were 5% higher ($126,753/CHR) in DASA-only and 41% higher ($169,990/CHR) in NILO-only. Likewise, compared with the 2G-TKI costs per MCyR in open access ($198,284/MCyR), the costs were 6% higher ($209,259/MCyR) in DASA-only and 22% higher ($241,515/MCyR) in NILO-only. CONCLUSION: Open access to both 2G-TKIs is associated with improved clinical and economic outcomes: greater treatment response rates (CHR and MCyR) and lower drug costs compared with restricted access to 2G-TKIs.