Combination of White Blood Cell Count at Presentation With Molecular Response at 3 Months Better Predicts Deep Molecular Responses to Imatinib in Newly Diagnosed Chronic-Phase Chronic Myeloid Leukemia Patients

Clinical Insights into Structure, Regulation, and Targeting of ABL Kinases in Human Leukemia

Chronic myeloid leukemia is a multistep, multi-lineage myeloproliferative disease that originates from a translocation event between chromosome 9 and chromosome 22 within the hematopoietic stem cell compartment. The resultant fusion protein BCR::ABL1 is a constitutively active tyrosine kinase that can phosphorylate multiple downstream signaling molecules to promote cellular survival and inhibit apoptosis. Currently, tyrosine kinase inhibitors (TKIs), which impair ABL1 kinase activity by preventing ATP entry, are widely used as a successful therapeutic in CML treatment. However, disease relapses and the emergence of resistant clones have become a critical issue for CML therapeutics. Two main reasons behind the persisting obstacles to treatment are the acquired mutations in the ABL1 kinase domain and the presence of quiescent CML leukemia stem cells (LSCs) in the bone marrow, both of which can confer resistance to TKI therapy. In this article, we systemically review the structural and molecular properties of the critical domains of BCR::ABL1 and how understanding the essential role of BCR::ABL1 kinase activity has provided a solid foundation for the successful development of molecularly targeted therapy in CML. Comparison of responses and resistance to multiple BCR::ABL1 TKIs in clinical studies and current combination treatment strategies are also extensively discussed in this article.

Identification of multivariable microRNA and clinical biomarker panels to predict imatinib response in chronic myeloid leukemia at diagnosis

Imatinib Mesylate (imatinib) was once hailed as the magic bullet for chronic myeloid leukemia (CML) and remains a front-line therapy for CML to this day alongside other tyrosine kinase inhibitors (TKIs). However, TKI treatments are rarely curative and patients are often required to receive life-long treatment or otherwise risk relapse. Thus, there is a growing interest in identifying biomarkers in patients which can predict TKI response upon diagnosis. In this study, we analyze clinical data and differentially expressed miRNAs in CD34+ CML cells from 80 patients at diagnosis who were later classified as imatinib-responders or imatinib-nonresponders. A Cox Proportional Hazard (CoxPH) analysis identified 16 miRNAs that were associated with imatinib nonresponse and differentially expressed in these patients. We also trained a machine learning model with different combinations of the 16 miRNAs with and without clinical parameters and identified a panel with high predictive performance based on area-under-curve values of receiver-operating-characteristic and precision-recall curves. Interestingly, the multivariable panel consisting of both miRNAs and clinical features performed better than either miRNA or clinical panels alone. Thus, our findings may inform future studies on predictive biomarkers and serve as a tool to develop more optimized treatment plans for CML patients in the clinic.

[Application and clinical significance of intercellular proximity labeling technique in chronic myelogenous leukemia]

Objective: This study aimed to explore the application of interaction-dependent fucosyl-biotinylation (FucoID), a chemical biology-based proximity labeling technique, in capturing tumor antigen-specific T cells and its clinical value in chronic myelogenous leukemia (CML) . Methods: Flow cytometry and fluorescence microscopy were employed to evaluate the experimental parameters for FucoID in CML. Peripheral blood samples were obtained from 14 newly diagnosed CML patients in the chronic phase. These samples underwent flow cytometry-based sorting and were subsequently labeled with FucoID to facilitate the isolation of tumor cells and T cells, followed by the immunophenotypic identification of tumor antigen-specific T cells. Finally, the diagnostic and therapeutic potential of FucoID in CML was assessed. Results: Initially, the experimental parameters for FucoID in CML were established. The proportion of CD3(+) T cells in patients was (8.96±6.47) %, exhibiting a marked decrease compared with that in healthy individuals at (38.89±22.62) %. The proportion of tumor-specific antigen-reactive T cells was (3.34±4.49) %, which demonstrated interpatient variability. In addition, the proportion of tumor-specific antigen-active T cells in CD4(+) T cells was (3.95±1.72) %, which was generally lower than the proportion in CD8(+) T cells at (5.68±2.18) %. Compared with those in tumor-specific antigen-nonreactive T cells, CCR7(-)CD45RA(-) effector memory T cells and CCR7(-)CD45RA(+) effector T cells were highly enriched in tumor-specific antigen-reactive T cells. Moreover, the intensity of tumor immune reactivity in patients exhibited a significant correlation with white blood cell count (WBC) and hemoglobin (HGB) levels in peripheral blood, while no such correlation was observed with other clinical baseline characteristics. Conclusion: The combination of FucoID and flow cytometry enables the rapid identification and isolation of tumor antigen-specific T cells in CML. The successful application of this method in CML and the implications of our findings suggest its potential clinical value in the field of hematologic malignancies.

Predictive scoring systems for molecular responses in persons with chronic phase chronic myeloid leukemia receiving initial imatinib therapy

It is vital for physicians and persons with chronic myeloid leukemia (CML) to accurately predict the likelihood of achieving a major molecular response (MMR) and a deep molecular response (DMR; at least MR⁴) at the start of imatinib-therapy, which could help in decision making of treatment goals and strategies. To answer this question, we interrogated data from 1369 consecutive subjects with chronic phase CML receiving initial imatinib-therapy to identify predictive co-variates. Subjects were randomly-assigned to training (n = 913) and validation (n = 456) datasets. Male sex, higher WBC concentration, lower haemoglobin concentration, higher percentage blood blasts and larger spleen size were significantly-associated with lower cumulative incidences of MMR and MR⁴ in training dataset. Using Fine-Gray model, we developed the predictive scoring systems for MMR and MR⁴ which classified subjects into the low-, intermediate- and high-risk cohorts with significantly-different cumulative incidences of MMR and MR⁴ with good predictive discrimination and accuracy in training and validation cohorts with high area under the receiver-operator characteristic curve (AUROC) values. These data may help physicians decide appropriateness of initial imatinib therapy.

A predictive scoring system for therapy-failure in persons with chronic myeloid leukemia receiving initial imatinib therapy

Data from 1,364 consecutive subjects with chronic-phase chronic myeloid leukemia (CML) receiving initial imatinib-therapy were interrogated to identify co-variates predicting therapy failure. Subjects were randomly divided into training (n = 908) and validation datasets (n = 456). In the training dataset, WBC count ≥120 × 10E + 9/L, haemoglobin concentration <115 g/L, blood basophils ≥12% and European Treatment and Outcome Study for CML Long-Term Survival (ELTS) risk score were significantly-associated with failure-free survival (FFS). Each co-variate was assigned 1 point to develop the imatinib-therapy failure (IMTF) model except ELTS high-risk category which was assigned 2 points based on multi-variable regression coefficients. Area under receiver-operator characteristic curve values in the IMTF model for 1-, 3- and 5-year FFS were 0.79-0.84 in the training dataset and 0.78-0.85 in the validation dataset. Calibration plots showed high agreement between predicted and observed outcomes. Decision curve analyses indicated subjects benefited from clinical use of this model. Cumulative incidences of imatinib-therapy failure and probabilities of FFS among the 5 risk cohorts (very low-, low-, intermediate-, high- and very high-risk) using the IMTF model were significantly different (all p values < 0.001). The IMTF model also correlated with probabilities of progression-free survival and survival (all p values < 0.001). These data should help physicians optimize TKI-therapy strategy at diagnosis in persons with chronic phase CML.

[Combination of socio-demographic and clinical co-variates for predicting treatment responses and outcomes in patients with chronic myeloid leukemia in the chronic phase]

Objective: To explore the impacts of socio-demographic and clinical co-variates on treatment responses and outcomes in patients with chronic myeloid leukemia in the chronic phase (CML-CP) receiving tyrosine kinase inhibitor (TKI) and identified the predictive models for them. Methods: Data of newly diagnosed adult patients with CML-CP receiving first-line TKI and having complete socio-demographic data and clinical information were reviewed. Cox model was used to identify the independent variables associated with complete cytogenetic response (CCyR) , major molecular response (MMR) , molecular response 4 (MR(4)) and molecular response 4.5 (MR(4.5)) , as well as failure-free survival (FFS) , progression-free survival (PFS) , overall survival (OS) and CML-related OS. Results: A total of 1414 CML-CP patients treated with first-line imatinib (n=1176) , nilotinib (n=170) or dasatinib (n=68) were reviewed. Median age was 40 (18-83) years and 873 patients (61.7% ) were males. Result of the multivariate analysis showed that lower educational level (P<0.001-0.070) and EUTOS long-term survival intermediate or high-risk (P<0.001-0.009) were significantly associated with lower cumulative incidences of CCyR, MMR, MR(4) and MR(4.5), as well as the inferior FFS, PFS, OS and CML-related OS. In addition, those who were males, from rural households, had white blood cells (WBC) ≥120×10(9)/L, hemoglobin (HGB) <115 g/L and treated with first-line imatinib had significantly lower cumulative incidences of cytogenetic and/or molecular responses. Being single, divorced or widowed, having, rural household registration, WBC≥120×10(9)/L, HGB<15 g/L, and comorbidity (ies) was significantly associated with inferior FFS, PFS, OS, and/or CML-related OS. Thereafter, the patients were classified into several subgroups using the socio-demographic characteristics and clinical variables by cytogenetic and molecular responses, treatment failure and disease progression, as well as overall survival and CML-related OS, respectively. There were significant differences in treatment responses and outcomes among the subgroups (P<0.001) . Conclusion: Except for clinical co-variates, socio-demographic co-variates significantly correlated with TKI treatment responses and outcomes in CML-CP patients. Models established by the combination of independent socio-demographic and clinical co-variates could effectively predict the responses and outcome.

Is the Sokal or EUTOS long-term survival (ELTS) score a better predictor of responses and outcomes in persons with chronic myeloid leukemia receiving tyrosine-kinase inhibitors?

Data from 1661 consecutive subjects with chronic-phase chronic myeloid leukemia (CML) receiving initial imatinib (n = 1379) or a 2^nd-generation tyrosine-kinase inhibitor (2G-TKI; n = 282) were interrogated to determine whether the Sokal or European Treatment and Outcome Study for CML (EUTOS) long-term survival (ELTS) scores were more accurate responses and outcome predictors. Both scores predicted probabilities of achieving complete cytogenetic response (CCyR), major molecular response (MMR), failure- and progression-free survivals (FFS, PFS), and survival in all subjects and those receiving imatinib therapy. However, the ELTS score was a better predictor of MR⁴, MR^4.5, and CML-related survival than the Sokal score. In subjects receiving 2G-TKI therapy, only the ELTS score accurately predicted probabilities of CCyR, MMR, MR⁴, FFS, and PFS. In the propensity score matching, subjects classified as intermediate risk by the ELTS score receiving a 2G-TKI had better responses (p < 0.001~0.061), FFS (p = 0.002), and PFS (p = 0.03) but not survival. Our data suggest better overall prediction accuracy for the ELTS score compared with the Sokal score in CML patients, especially those receiving 2G-TKIs. People identified as intermediate risk by the ELTS score may benefit more from initial 2G-TKI therapy in achieving surrogate endpoints but not survival, especially when a briefer interval to stopping TKI therapy is the therapy objective.

Molecular response to imatinib in patients with chronic myeloid leukemia in Tanzania

Imatinib is the mainstay of treatment of patients with chronic myeloid leukemia (CML) in Tanzania. Monitoring molecular response to therapy by real-time polymerase chain reaction at defined milestones is necessary for early detection of treatment failure. However, this assay is not routinely performed in Tanzania; therefore, the depth of molecular response among patients with CML is not known. A total of 158 patients with previously diagnosed CML who received imatinib treatment were recruited from January 2019 and followed up through October 2020 at Ocean Road Cancer Institute. Information was obtained at the time of diagnosis and follow-up. Blood samples were collected in EDTA tubes to measure the BCR/ABL ratio on the Gene Xpert system for molecular response determination. The median age of the 158 adult patients was 45 years (range, 18-86). By reference to established treatment milestones, only 37 (23.4%) achieved optimal molecular response. Signs of advanced-stage disease, in particular the need for red cell transfusions before diagnosis (adjusted odds ratio [AOR], 3.4; 95% CI, 1.32-9.17) and cytopenias (AOR, 2.26; 95% CI, 1.03-4.96) necessitating drug interruptions were statistically validated predictors of treatment failure on multivariate, multinomial logistic regression. Patient survival at the 22-month follow-up was lowest, with 78.6% (95% CI, 69.4-85.4) in the failure-to-respond category and highest in patients achieving optimal response 97.0% (95% CI, 80.9-99.6). In summary, the majority of patients with CML treated with imatinib in Tanzania do not obtain deep molecular response. This outcome can be attributed to late diagnosis, the development of cytopenias requiring multiple drug interruptions, and poor adherence to treatment.

The Levels of FoxO3a Predict the Failure of Imatinib Mesylate Therapy among Chronic Myeloid Leukemia Patients

INTRODUCTION: Forkhead Transcription Factor 3a (FoxO3a) has been proposed to have a high efficacy to predict the failure of imatinib mesylate (IM) therapy among Chronic Myeloid Leukemia (CML) patients. However, the limited evidence had made this marker remained controversy. OBJECTIVES: We aimed to investigate the correlation between the levels of FoxO3a and the risk of treatment failure of IM therapy in CML patients. METHODS: A prospective cohort study was carried out between February 2019 and February 2020 in Saiful Anwar Hospital, Malang, Indonesia. All CML patients treated with IM on our hospital during the study period were included. The levels of FoxO3a was determined using the Enzyme-linked immunosorbent assay (ELISA) using Cusabio Biotech Kit (Cusabio Biotech Co., New York, USA). The treatment response was assessed using the European Leukemia criteria. The correlation and effect estimate between the levels of FoxO3a and treatment response of CML patients was assessed using multiple logistic regression. RESULTS: 53 CML patients receiving IM in our hospital were included, consisting of 29 patients with good response and 24 patients with non-response. Our study found that CML patients with lower levels of FoxO3a was associated with increased risk to develop treatment failure when treated with IM. Moreover, we also found that higher risk of treatment failure of IM therapy was also found in patients with increased levels of thrombocytes, basophils, and leukocytes, and lower levels of hemoglobin. CONCLUSION: We reveal that FoxO3a is the prominent marker to predict the treatment response of CML patients treated with IM.

Moderate anemia at diagnosis is an independent prognostic marker of the EUTOS, Sokal, and Hasford scores for survival and treatment response in chronic-phase, chronic myeloid leukemia patients with frontline imatinib

OBJECTIVES

This study aimed to examine the prognostic value of anemia for the diagnosis of chronic myeloid leukemia in the chronic phase (CML-CP) receiving imatinib.

METHODS

One hundred and fifty-four CML-CP patients were enrolled. The influences of moderate anemia with hemoglobin (Hb) < 10 g/dl, four scoring systems, and the early molecular response at 3 months (BCR-ABL ≤10%; 3M-EMR) on the achievement of a deep molecular response (DMR, MR4.5), progression-free survival (PFS), event-free survival (EFS), and overall survival (OS) were compared.

RESULTS

Moderate anemia was identified in 44 (28.6%) patients. These patients had more aggressive baseline features and higher risks, as assessed by scoring systems, and less favorable treatment responses vs those without anemia, including 3M-EMR (50.0% vs 69.1%), a complete cytogenetic response at 6 months (20.5% vs 50.9%), and a major molecular response at 12 months (22.5% vs 45.2%), with a median follow-up of 54.0 months. Furthermore, an Hb of 10 g/dl better distinguished DMR, EFS, PFS, and OS than the EUTOS, Sokal, and Hasford scores, and better predicted the responses and survivals in combination with 3M-EMR than 3M-EMR alone.

CONCLUSIONS

This finding highlights the significance of anemia in CML-CP, and suggests that patients with anemia at diagnosis should be carefully monitored and might benefit from more potent TKIs if not achieving 3M-EMR.

[Analysis on tyrosine kinase inhibitor discontinuation in patients with chronic myeloid leukemia in the real world: experience from single center]

Objective: To explore status of tyrosine kinase inhibitor (TKI) discontinuation in patients with chronic myeloid leukemia (CML) in the chronic phase (CP) in the real world, to analyze causes, factors and outcomes associated with TKI discontinuation and the possibility of pursuit treatment-free remission (TFR) in China. Methods: From January 2013 to August 2016, data of CML-CP patients in Peking University People's Hospital which were not enrolled in clinical trials were retrospectively collected and analyzed. Results: Data of 662 CML-CP patients were collected. With a median follow-up after TKI-therapy of 26 months (range, 3-187 months) , 187 patients (28.2%) experienced TKI cessation of at least 2 weeks. Causes of TKI discontinuation included hematologic adverse events 57.8% (n=108) , non-hematologic adverse events 30.4% (n=57) , financial burden 25.1% (n=47) , and others 7.0% (n= 13) . Multivariate analyses showed female, ≥40 years, no co-morbidity, and interval from diagnosis to TKI initiation ≥6 months, TKI switch and patients from other hospitals were factors associated with TKI discontinuation because of hematologic adverse effects. Female and patients from other hospitals were factors associated with TKI discontinuation because of non-hematologic adverse effect. TKI switch, generic TKI used and patients from other hospitals were factors associated with TKI discontinuation because of financial toxicity. Patients TKI discontinuation because of hematologic, non-hematologic or financial toxicity achieved a lower complete cytogenetic response or complete molecular response (CMR) than those with uninterrupted TKI-therapy. Patients with TKI discontinuation because of hematologic or financial toxicity had a shorter progression-free survival than those with uninterrupted TKI-therapy. 5 of 7 patients who obtained sustained CMR and discontinued TKI-therapy experienced disease recurrence with a median duration of 3 months (range, 2-32 months) . In 39 patients from other hospitals who aimed to confirm their optimal response of sustained CMR in Peking University People's Hospital, 21 (53.8%) were BCR-ABL positive. Conclusion: In the real world in China, half of CML-CP patients who discontinued TKI-therapy were incurred to TKI-related hematologic adverse effect, and both a quarter of them, TKI-related non-hematologic toxicities and financial toxicity, respectively. Discontinued TKI-therapy due to hematologic adverse events or financial toxicity was associated with lower TKI-therapy response rates. Nowadays, based on the Chinese situation, it is too early to talk about TFR.

Concordant optimal molecular and cytogenetic responses at both 3 and 6 months predict a higher probability of MR4.5 achievement in patients with chronic myeloid leukemia treated with imatinib

To investigate the impact of the combination of early molecular and cytogenetic responses on the achievement of MR4.5, 228 newly diagnosed chronic phase chronic myeloid leukemia patients treated with imatinib were categorized into 3-month and 6-month concordant optimal, discordant, concordant warning, and failure groups. Among them, 85.3% at 3 months and 78.1% at 6 months had concordant molecularly and cytogenetically defined responses. At both 3 and 6 months, patients with discordant, concordant warning and failure responses had similar 3-year MR4.5 rates, and all were significantly lower than the rate in patients with concordant optimal responses. Patients with concurrent 3-month and 6-month concordant optimal responses had a significantly higher 3-year MR4.5 rate than those with other responses, and 3-month and 6-month concurrent molecular optimal, but not cytogenetic optimal responses. Therefore, achieving concordant optimal molecular and cytogenetic responses at both 3 and 6 months with imatinib treatment are associated with MR4.5 achievement.