Clinico-laboratory pertinences and management of relapsed and refractory.

PURPOSE: The purpose of this study was to assess the biological significance of lactate dehydrogenase (LDH), T315I mutation and treatment options in newly diagnosed and relapsed patients with chronic myeloid leukemia (CML). METHODS: Our clinical-analytical and descriptive study enrolled 27 patients with different phases of CML, who were followed up and treated at the Institute of Oncology between 1995-2020. Venous blood samples were taken for LDH measurement, molecular screening and detection of T315I mutation of the ABL gene in order to investigate the biological significance of the increased LDH values and T315I mutation. CML patients underwent chemotherapy with alkylating agents, antimetabolites and tyrosine kinase inhibitors (TKIs). RESULTS: The patient age ranged from 20 to 67 years (mean 51.3±2,14). The diagnosis of CML was established in the late chronic phase in 25 (92.6%) patients. The quantitative real-time PCR revealed p210 transcript of the BCR-ABL chimeric gene in all cases, with the range of 23.17-100% and median value of 74.73±3.21%. LDH at diagnosis ranged between 169-1609.4 U/L and was increased in 14 (63.6%) patients, especially in those with leukocytosis over 100x109/l. The complete cytogenetic and complete or major molecular responses were recorded under treatment with different generations of TKIs in 16 (59.3%) cases, including 3 cases with T315I mutation. Relapses occurred in 10 (71.4%) patients with initially increased LDH values and in 5 of 6 patients with T315I mutation. One (3.7%) patient with T315I mutation evolved into the acute phase disease, and achieved the complete hematological response after treatment with ponatinib, a 3rd generation TKI. The survival of patients from the disease onset till the last monitoring visit ranged between 21 and 234.8 months (median 93.97±4.52). CONCLUSIONS: The increased LDH values may indicate the activity at diagnosis and relapse of CML. In our study T315I mutation of the ABL gene and the increased values of LDH were associated with a higher rate of relapses and resistance to imatinib. Notwithstanding the treatment line and in relapses TKIs improve considerably the survival and ECOG-WHO score of CML patients.

Assessment of droplet digital polymerase chain reaction for measuring BCR-ABL1 in chronic myeloid leukaemia in an international interlaboratory study.

Measurement of BCR activator of RhoGEF and GTPase -ABL proto-oncogene 1, non-receptor tyrosine kinase (BCR-ABL1) mRNA levels by reverse transcription quantitative polymerase chain reaction (RTqPCR) has been critical to treatment protocols and clinical trials in chronic myeloid leukaemia; however, interlaboratory variation remains a significant issue. Reverse transcriptase droplet digital PCR (RTddPCR) has shown potential to improve testing but a large-scale interlaboratory study is required to definitively establish this. In the present study, 10 BCR-ABL1-positive samples with levels ranging from molecular response (MR)1·0 -MR5·0 were tested by 23 laboratories using RTddPCR with the QXDX BCR-ABL %IS kit. A subset of participants tested the samples using RTqPCR. All 23 participants using RTddPCR detected BCR-ABL1 in all samples to MR4·0 . Detection rates for deep-response samples were 95·7% at MR4·5 , 78·3% at MR4·7 and 87·0% at MR5·0 . Interlaboratory coefficient of variation was indirectly proportional to BCR-ABL1 level ranging from 29·3% to 69·0%. Linearity ranged from 0·9330 to 1·000 (average 0·9936). When results were compared for the 11 participants who performed both RTddPCR and RTqPCR, RTddPCR showed a similar limit of detection to RTqPCR with reduced interlaboratory variation and better assay linearity. The ability to detect deep responses with RTddPCR, matched with an improved linearity and reduced interlaboratory variation will allow improved patient management, and is of particular importance for future clinical trials focussed on achieving and maintaining treatment-free remission.

Relationship between trough level of tyrosine kinase inhibitor (imatinib and nilotinib) and BCR-ABL ratios in an Indonesian chronic-phase chronic myeloid leukemia (CML) population.

Objectives Among Chronic Myeloid Leukemia (CML) patients treated with Tyrosine Kinase Inhibitor (TKI-imatinib-nilotinib), some showed a suboptimal response. Based on pharmacokinetic studies, TKI trough level ( C m i n ∞ ${C}_{min}\hat{\infty }$ ) is associated with clinical outcomes, reflected by the BCR-ABL ratio. However, the interindividual pharmacokinetic variability of imatinib and nilotinib is found to be moderate-high. This study aims to analyze the relationship between TKI C m i n ∞   ${C}_{min}\hat{\infty }$ and BCL-ABL ratio in chronic-phase CML patients. Methods Cross-sectional study to CML chronic-phase patients treated with imatinib 400 mg daily or nilotinib 400 or 800 mg daily for ≥12 months. The exclusion criteria were therapy discontinuation within 29 days (imatinib) or 8 days (nilotinib) before the sampling day. Blood samples were drawn 1 h before the next dose. Imatinib-nilotinib C m i n ∞ ${C}_{min}\hat{\infty }$ and BCR-ABL ratio were measured using HPLC and RT-qPCR. The relationship was analyzed using bivariate correlation Spearman's rho test. Results Twenty-three imatinib and 11 nilotinib patients met the inclusion criteria. The mean imatinib and nilotinib C m i n ∞ ${C}_{min}\hat{\infty }$ were 1,065.46 ± 765.71 and 1,445 ± 1,010.35 ng/mL respectively. There were large interindividual variations in both groups (71.87% vs. 69.88%). Half of the patients in each group were found to reach C m i n ∞ ${C}_{min}\hat{\infty }$ target (≥1.000 ng/mL, imatinib; ≥800 ng/mL nilotinib), but only 12 (35,29%) of them result in BCR-ABL ratio ≤0.1%. C m i n ∞   ${C}_{min}\hat{\infty }$ imatinib was found to be significantly associated with BCR-ABL ratio. But, not with the nilotinib group. Conclusions There were high interindividual variations of imatinib and nilotinib correlated with BCR-ABL ratio, but no correlation in nilotinib.

Expression of Ki-67 and CD34 on blood and bone marrow cells of CML patients with different response to imatinib and nilotinib therapy.

AIM: To assess the expression of Ki-67 protein and CD34 antigen on peripheral blood (PB) and bone marrow (BM) cells in chronic myelogenous leukemia (CML) patients with different response to tyrosine kinase inhibitors (TKI) imatinib (IM) and nilotinib (NI) therapy. PATIENTS AND METHODS: BM aspirate and PB samples from 41 CML patients treated with IM and NI were studied by cytogenetic, molecular genetic, and flow cytometry methods. According to the response to TKIs, the patients were distributed into the optimal response, warning, and treatment failure groups. RESULTS: The patients with optimal response to TKI therapy showed the lowest levels of Ki-67 expression in PB and BM compared with the patients from warning and falure treatment groups, however, Ki-67 expression was close to the reference values in PB (0.7 ± 0.3)%, only in NI-treated patients, The highest expression of Ki-67 in PB was observed in patients from treatment failure groups. In PB of patients who received NI and did not achieve optimal response, CD34+ cell count increased by almost 4 times compared with that in the optimal response group. The results indicated that CD34+ cell pool expanded in patients with poor response to both IM and NI. In patients with optimal response to NI therapy, CD34+ cell counts in PB were within the reference range ​​and did not exceed 0.5%. Similar results were observed for Ki-67 and CD34+ in BM hematopoietic cells. CONCLUSIONS: Ki-67 expression and CD34+ cell count in PB and BM of CML patients increased with the acquisition of clonal resistance to IM and NI. NI provides a deeper molecular response compared with IM.

Prospects for achieving treatment-free remission in chronic myeloid leukaemia.

In addition to the best possible overall survival, discontinuation of the tyrosine kinase-inhibitor (TKI) treatment [treatment free remission (TFR)] without observing a recurrence of the disease has become a major goal of the therapy of chronic myelogenous leukemia (CML). Many clinical studies have demonstrated that TFR is possible, although for the moment limited to a fraction of the CML patients able to achieve a stable deep molecular response (DMR). The factors associated to the possibility of remaining in TFR or of losing it, have been investigated by a number of controlled and observation clinical trials and although total TKI treatment duration, DMR duration and stability and, more recently, also the depth of the molecular response obtained at the time of discontinuation have been shown to be significant elements, most of the factors associated with a higher possibility of a successful discontinuation still remain elusive and are here reviewed.

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.

Imatinib independent aberrant methylation of NOV/CCN3 in chronic myelogenous leukemia patients: a mechanism upstream of BCR-ABL1 function?

BACKGROUND: The NOV gene product, CCN3, has been reported in a diverse range of tumors to serve as a negative growth regulator, while acting as a tumor suppressor in Chronic Myelogenous Leukemia (CML). However, the precise mechanism of its silencing in CML is poorly understood. In the current study, we aimed to query if the gene regulation of CCN3 is mediated by the promoter methylation in the patients with CML. In addition, to clarify whether the epigenetic silencing is affected by BCR-ABL1 inhibition, we assessed the methylation status in the patients at different time intervals following the tyrosine kinase inhibition using imatinib therapy, as the first-line treatment for this type of leukemia. METHODS: To address this issue, we applied bisulfite-sequencing technique as a high-resolution method to study the regulatory segment of the CCN3 gene. The results were analyzed in newly diagnosed CML patients as well as following imatinib therapy. We also evaluated the correlation of CCN3 promoter methylation with BCR-ABL1 levels. RESULTS: Our findings revealed that the methylation occurs frequently in the promoter region of CML patients showing a significant increase of the methylated percentage at the CpG sites compared to normal individuals. Interestingly, this hypermethylation was indicated to be independent of BCR-ABL1 titers in both groups, which might suggest a mechanism beyond the BCR-ABL1 function. CONCLUSION: Despite suggesting that the CCN3 hypermethylation acts as a molecular mechanism independent of BCR-ABL1 function in CML patients, this scenario requires further validation by complementary experiments. In the case of acting upstream of BCR-ABL1 signaling, the methylation marker can provide early detection and a novel platform for targeted epigenetic modifiers for efficient treatment in imatinib resistant patients.

The clinical outcomes of chronic myeloid leukemia patients harboring alternatively spliced BCR-ABL variants.

Objectives and importance: Tyrosine kinase inhibitors (TKIs) are indispensable for the treatment of chronic myeloid leukemia (CML). However, alternative splicing variants have been recently proposed as mechanisms of TKI resistance, although the clinical significance of these mutations remains controversial. We here present the long-term clinical courses of three CML patients harboring such unique mutations and try to assess their clinical significances. Moreover, the exon 6 frameshift presented here has been rarely reported, which may provide important information on this rare mutation. Clinical presentation: We report three cases of CML harboring an exon 7 deletion, insertion of 35 intronic nucleotides and an exon 6 frameshift, respectively. Remarkably, all patients obtained better than molecular response4.0 following administration of TKIs. Discussion and conclusion: Three CML cases highlighted an association between such splicing variants and clinical outcomes. The premature termination in the kinase domain due to these mutations likely causes conformational changes and inhibits TKI binding, but it also results in abrogating kinase activities of CML cells. Thus, the above-mentioned mutants might less affect outcomes of treatment. Noteworthy, clinically available International Scale RT-PCR system cannot distinguish kinase-active mutants from kinase-inactive mutants, which may possibly influence upon interpretation of the treatment efficacy. Clonal quantification on respective mutants could more precisely evaluate CML status in these patients. Therefore, one should realize these important splicing variants and accumulate further experiences.

A simple fluorescence biosensing strategy for ultrasensitive detection of the BCR-ABL1 fusion gene based on a DNA machine and multiple primer-like rolling circle amplification.

A one-step, rapid fluorescence biosensing method has been developed for ultrasensitive detection of the BCR-ABL1 fusion gene based on a polymerase/nicking endonuclease DNA machine and multiple primer-like rolling circle amplification (RCA). In the strategy, the BCR-ABL1 fusion gene can be specifically identified by using a dual probe to form a three-way junction structure (3-WJ). Then the 3-WJ based DNA machine is driven by polymerase and nicking endonuclease to generate a large number of triggers, initiating a downstream RCA reaction. The introduction of two nicking endonuclease recognition sites into a circular DNA template makes RCA occur in a multiple primer-like manner, achieving exponential growth of the signal. Benefiting from the cascade amplification, the developed method generates a wide linear response from 10 fM to 1 nM with a low detection limit of 5.52 fM. In addition, the one-step operation allows the assay to be completed within 60 min and acceptable recovery is obtained in complex samples. These merits endow the biosensing strategy with certain potential for the clinical diagnosis and scientific research of the BCR-ABL1 fusion gene.

Discontinuation of tyrosine kinase inhibitors in chronic myeloid leukemia: Recommendations for clinical practice from the French Chronic Myeloid Leukemia Study Group.

BACKGROUND: The ultimate goal of chronic myeloid leukemia management in the tyrosine kinase inhibitor (TKI) era for patients who obtain deep molecular responses is maintaining a durable off-treatment response after treatment discontinuation; this situation is called treatment-free remission (TFR). Knowledge accumulated during the last 10 years justifies moving TFR strategies from research to clinical practice. METHODS: Twenty experts from the French Chronic Myeloid Leukemia Study Group (France Intergroupe des Leucémies Myéloïdes Chroniques), including 17 hematologists, 2 molecular biologists, and 1 cytogeneticist, critically reviewed published data with the goal of developing evidence-based recommendations for TKI discontinuation in clinical practice. RESULTS: Clinically relevant questions were addressed, including the selection of candidate patients (with known prognostic factors for outcomes taken into account), detailed monitoring procedures during the treatment-free phase, a definition of relapse requiring therapy resumption, and monitoring after treatment reintroduction. CONCLUSIONS: This work presents consensus statements with the aim of guiding physicians and biologists by means of pragmatic recommendations for safe TKI discontinuation in daily practice. Cancer 2018;124:2956-63. © 2018 American Cancer Society.

Myeloproliferative neoplasms with concurrent BCR-ABL1 translocation and JAK2 V617F mutation: a multi-institutional study from the bone marrow pathology group.

Myeloproliferative neoplasms arise from hematopoietic stem cells with somatically altered tyrosine kinase signaling. Classification of myeloproliferative neoplasms is based on hematologic, histopathologic and molecular characteristics including the presence of the BCR-ABL1 and JAK2 V617F. Although thought to be mutually exclusive, a number of cases with co-occurring BCR-ABL1 and JAK2 V617F have been identified. To characterize the clinicopathologic features of myeloproliferative neoplasms with concomitant BCR-ABL1 and JAK2 V617F, and define the frequency of co-occurrence, we conducted a retrospective multi-institutional study. Cases were identified using a search of electronic databases over a decade at six major institutions. Of 1570 patients who were tested for both BCR-ABL1 and JAK2 V617F, six were positive for both. An additional five patients were identified via clinical records providing a total of 11 cases for detailed evaluation. For each case, clinical variables, hematologic and genetic data, and bone marrow histomorphologic features were analyzed. The sequence of identification of the genetic abnormalities varied: five patients were initially diagnosed with a JAK2 V617F+ myeloproliferative neoplasm, one patient initially had BCR-ABL1+ chronic myeloid leukemia, while both alterations were identified simultaneously in five patients. Classification of the BCR-ABL1-negative myeloproliferative neoplasms varied, and in some cases, features only became apparent following tyrosine kinase inhibitor therapy. Seven of the 11 patients showed myelofibrosis, in some cases before identification of the second genetic alteration. Our data, reflecting the largest reported study comprehensively detailing clinicopathologic features and response to therapy, show that the co-occurrence of BCR-ABL1 and JAK2 V617F is rare, with an estimated frequency of 0.4%, and most often reflects two distinct ('composite') myeloproliferative neoplasms. Although uncommon, it is important to be aware of this potentially confounding genetic combination, lest these features be misinterpreted to reflect resistance to therapy or disease progression, considerations that could lead to inappropriate management.

Prediction for sustained deep molecular response of BCR-ABL1 levels in patients with chronic myeloid leukemia in chronic phase.

BACKGROUND: The achievement of a sustained deep molecular response is a goal of increasing relevance because it opens the possibility of treatment discontinuation. The objective of this analysis was to develop a prediction model for a sustained molecular response with BCR-ABL1 level <0.0032% on the international scale (MR4.5 ) for at least 2 years according to BCR-ABL1 levels achieved within the first 12 months of therapy. METHODS: Data for 603 patients with newly diagnosed chronic myeloid leukemia in chronic phase in consecutive prospective clinical trials were analyzed. The best fit average molecular response was defined by robust linear regression models, with which the average molecular levels were defined. The minimum acceptable molecular response was defined by quantile regression for the 95th percentile, with which the worst 5% BCR-ABL1 levels were identified. RESULTS: In 603 patients with a median follow-up of 103 months, 2002 BCR-ABL1-level data points within 1 year of tyrosine kinase inhibitors were identified. The regression equation for the best fit average levels for a sustained MR4.5 was Log10 (PCR) = -0.1424 × (Months) - 0.8668, and the regression equation for minimum acceptable levels was Log10 (PCR) = -0.1403 × (Months) + 0.6142 (where PCR indicates polymerase chain reaction). To achieve a sustained MR4.5 , the best fit average levels were 0.051%, 0.019%, 0.007%, and 0.003% at 3, 6, 9, and 12 months, respectively; the minimum acceptable levels were 1.561%, 0.592%, 0.225%, and 0.085% at 3, 6, 9, and 12 months, respectively. CONCLUSIONS: This model proposes optimal values that predict the highest probability of reaching such a goal. These values can be used to guide therapy when a sustained MR4.5 is the objective. Cancer 2018;124:1160-8. © 2017 American Cancer Society.

Medical Devices; Immunology and Microbiology Devices; Classification of the BCR­ABL Quantitation Test. Final order.

The Food and Drug Administration (FDA or we) is classifying the BCR-ABL quantitation test into class II (special controls). The special controls that apply to the device type are identified in this order and will be part of the codified language for the BCR-ABL quantitation test's classification. We are taking this action because we have determined that classifying the device into class II (special controls) will provide a reasonable assurance of safety and effectiveness of the device. We believe this action will also enhance patients' access to beneficial innovative devices, in part by reducing regulatory burdens.

Mixed-Phenotype Acute Leukemia: Diagnostic Criteria and Pitfalls.

Mixed-phenotype acute leukemia (MPAL) is a heterogeneous category in the World Health Organization classification that comprises acute leukemias with discrete admixed populations of myeloid and lymphoid blasts ("bilineal") or with extensive coexpression of lymphoid and myeloid markers in a single blast population ("biphenotypic"). Flow cytometric findings suggestive of MPAL are often met with consternation by pathologists and oncologists alike, owing to unfamiliarity with the disease and uncertainty about how MPAL fits into established paradigms for treatment of acute leukemia. The purpose of this review is to explain the diagnostic criteria for MPAL, summarize its biological and clinical features, and address common diagnostic pitfalls of these unusual leukemias.