Treatment and monitoring of Philadelphia chromosome-positive leukemia patients: recent advances and remaining challenges

LncRNA IRAIN overcomes imatinib resistance in chronic myeloid leukemia via NF-κB/CD44 pathway inhibition

The development of tyrosine kinase inhibitors (TKIs) has revolutionarily increased the overall survival of patients with chronic myeloid leukemia (CML). However, drug resistance remains a major obstacle. Here, we demonstrated that a BCR-ABL1-independent long non-coding RNA, IRAIN, is constitutively expressed at low levels in CML, resulting in imatinib resistance. IRAIN knockdown decreased the sensitivity of CD34+ CML blasts and cell lines to imatinib, whereas IRAIN overexpression significantly increased sensitivity. Mechanistically, IRAIN downregulates CD44, a membrane receptor favorably affecting TKI resistance, by binding to the nuclear factor kappa B subunit p65 to reduce the expression of p65 and phosphorylated p65. Therefore, the demethylating drug decitabine, which upregulates IRAIN, combined with imatinib, formed a dual therapy strategy which can be applied to CML with resistance to TKIs.

Advances in molecular targeted drugs in combination with CAR-T cell therapy for hematologic malignancies

Molecular targeted drugs and chimeric antigen receptor (CAR) T cell therapy represent specific biological treatments that have significantly improved the efficacy of treating hematologic malignancies. However, they face challenges such as drug resistance and recurrence after treatment. Combining molecular targeted drugs and CAR-T cells could regulate immunity, improve tumor microenvironment (TME), promote cell apoptosis, and enhance sensitivity to tumor cell killing. This approach might provide a dual coordinated attack on cancer cells, effectively eliminating minimal residual disease and overcoming therapy resistance. Moreover, molecular targeted drugs can directly or indirectly enhance the anti-tumor effect of CAR-T cells by inducing tumor target antigen expression, reversing CAR-T cell exhaustion, and reducing CAR-T cell associated toxic side effects. Therefore, combining molecular targeted drugs with CAR-T cells is a promising and novel tactic for treating hematologic malignancies. In this review article, we focus on analyzing the mechanism of therapy resistance and its reversal of CAR-T cell therapy resistance, as well as the synergistic mechanism, safety, and future challenges in CAR-T cell therapy in combination with molecular targeted drugs. We aim to explore the benefits of this combination therapy for patients with hematologic malignancies and provide a rationale for subsequent clinical studies.

Advancements in minimal residual disease detection: a practical approach using single-cell droplet PCR for comprehensive monitoring in hematological malignancy

The identification of chromosomal abnormalities accompanied by copy number alterations is important for understanding tumor characteristics. Testing methodologies for copy number abnormality have limited sensitivity, resulting in their use only for the sample provided at the time of diagnosis or recurrence of malignancy, but not for the monitoring of minimal residual disease (MRD) during and after therapy. We developped the "DimShift" technology which enable to measure the copy number of target gene/chromosome in each cell, which is given by the single cell droplet PCR. Qualitative result of DimShift given by peripheral blood was perfectly concordant with that of bone marrow. These findings and performances are promising to be the new methodology for MRD detection in malignant diseases utilizing bone marrow as well as peripheral blood.

Investigation of the mechanism of USP28-mediated IFITM3 elevation in BCR-ABL-dependent imatinib resistance in CML

Due to resistance and BCR-ABLT315I-mutated, CML remains a clinical challenge. It needs new potential therapeutic targets to overcome CML resistance related to BCR-ABL. Our research revealed that the deubiquitinating enzyme USP28 was highly expressed in BCR-ABL-dependent CML patients. Similarly, a high expression of USP28 was found in the K562 cell line, particularly in the imatinib-resistant strains. Notably, USP28 directly interacted with BCR-ABL. Furthermore, when BCR-ABL and its mutant BCR-ABLT315I were overexpressed in K562-IMR, they promoted the expression of IFITM3. However, when small molecule inhibitors targeting USP28 and small molecule degraders targeting BCR-ABL were combined, they significantly inhibited the expression of IFITM3. The experiments conducted on tumor-bearing animals revealed that co-treated mice showed a significant reduction in tumor size, effectively inhibiting the progression of CML tumors. In summary, USP28 promoted the proliferation and invasion of tumor cells in BCR-ABL-dependent CML by enhancing the expression of IFITM3. Moreover, imatinib resistance might be triggered by the activation of the USP28-BCR-ABL-IFITM3 pathway. Thus, the combined inhibition of USP28 and BCR-ABL could be a promising approach to overcome CML resistance dependent on BCR-ABL.

Pharmacovigilance study of BCR-ABL1 tyrosine kinase inhibitors: a safety analysis of the FDA adverse event reporting system

BACKGROUND

With the increased use of BCR-ABL1 tyrosine kinase inhibitors (TKIs) in cancer patients, adverse events (AEs) have garnered considerable interest. We conducted this pharmacovigilance study to evaluate the AEs of BCR-ABL1 TKIs in cancer patients using the Food and Drug Administration Adverse Event Reporting System (FAERS) database.

METHODS

To query AE reports from the FAERS database, we used OpenVigil 2.1. Descriptive analysis was then employed to describe the characteristics of TKIs-associated AE reports. We also utilized the disproportionality analysis to detect safety signals by calculating the proportional reporting ratio (PRR) and reporting odds ratios (ROR).

RESULTS

From the FAERS database, a total of 85,989 AE reports were retrieved, with 3,080 significant AE signals identified. Specifically, imatinib, nilotinib, dasatinib, bosutinib, and ponatinib had significant AE signals of 1,058, 813, 232, 186, and 791, respectively. These significant signals were further categorized into 26 system organ classes (SOCs). The AE signals of imatinib and ponatinib were primarily associated with general disorders and administration site conditions. On the other hand, nilotinib, dasatinib, and bosutinib were mainly linked to investigations, respiratory, thoracic and mediastinal disorders, and gastrointestinal disorders, respectively. Notably, new signals of 245, 278, 47, 55, and 253 were observed in imatinib, nilotinib, dasatinib, bosutinib, and ponatinib, respectively.

CONCLUSIONS

The results of this study demonstrated that AE signals differ among the five BCR-ABL1 TKIs. Furthermore, each BCR-ABL1 TKI displayed several new signals. These findings provide valuable information for clinicians aiming to reduce the risk of AEs during BCR-ABL1 TKI treatment.

A case report of a truncated ABL1 mutation in 2 cases with Philadelphia chromosome-positive B cell precursor acute lymphoblastic leukemia

Acquired point mutations in the ABL1 gene are widely recognized as a cause of Philadelphia chromosome-positive B cell precursor acute lymphoblastic leukemia (Ph+ B-ALL) that is resistant to tyrosine kinase inhibitors, whereas there are few reports about other types of the ABL1 mutation. Here, we report 2 cases of Ph+ B-ALL gaining a partial deletion type mutation of the ABL1 gene (Δ184-274 mutation), which resulted in truncation of the ABL1 molecule and loss of kinase activity. In both cases, the disease was refractory to multiple agents in the recurrent phase after allogeneic hematopoietic cell transplantation. This is a case report of a truncated ABL1 mutation in 2 patients with Ph+ B-ALL.

How to Manage Philadelphia-Positive Acute Lymphoblastic Leukemia in Resource-Constrained Settings

Recent studies have indicated that more than half of adult patients newly diagnosed with Ph+ ALL can now achieve a cure. However, determining the most suitable protocol for less-resourced settings can be challenging. In these situations, we must consider the potential for treatment toxicity and limited access to newer agents and alloSCT facilities. Currently, it is advisable to use less intensive induction regimens for Ph+ ALL. These regimens can achieve high rates of complete remission while causing fewer induction deaths. For consolidation therapy, chemotherapy should remain relatively intensive, with careful monitoring of the BCR-ABL1 molecular transcript and minimal residual disease. AlloSCT may be considered, especially for patients who do not achieve complete molecular remission or have high-risk genetic abnormalities, such as IKZF1-plus. If there is a loss of molecular response, it is essential to screen patients for ABL mutations and, ideally, change the TKI therapy. The T315I mutation is the most common mechanism for disease resistance, being targetable to ponatinib. Blinatumomab, a bispecific antibody, has shown significant synergy with TKIs in treating this disease. It serves as an excellent salvage therapy, aside from achieving outstanding results when incorporated into the frontline.

Identification by molecular dynamic simulation and in vitro validation of SISB-A1, N-[1-(4-bromophenyl)-3-methyl-1H-pyrazol-5-yl]-2-[(2-oxo-4-phenyl-2H-chromen-7-yl) oxy], as an inhibitor of the AblT315I mutant kinase to combat imatinib resistance in chronic myeloid leukemia

The discovery of imatinib, a specific inhibitor of Abl kinase, revolutionized the therapeutic approach to chronic myeloid leukemia (CML); however, its efficacy can be impeded by the emergence of novel mutations within the kinase domain, particularly AblT315I, that lead to the development of drug resistance. It therefore remains necessary to identify specific inhibitors that can effectively target imatinib-resistant CML harboring the AblT315I mutation. A natural product library sourced from the ZINC database was screened against the experimental structure of AblT315I kinase to identify compounds that selectively target the mutated kinase. The top-scoring compound was empirically tested for inhibition of AblT315I kinase using a luminescence-based kit and for impact on cellular proliferation using the BaF3-BCR-ABL-T315I stable cell line. Computational docking and molecular dynamic simulations identified the compound SISB-A1, N-[1-(4-bromophenyl)-3-methyl-1H-pyrazol-5-yl]-2-[(2-oxo-4-phenyl-2H-chromen-7-yl)oxy] acetamide, to effectively bind the catalytic domain of the mutant AblT315I kinase. Moreover, SISB-A1 exhibited greater preference than imatinib for amino acid residues of the mutant kinase's active site, including isoleucine 315. MMPBSA-based Gibbs binding free energy estimation predicted SISB-A1 to have a free energy of -51.5 versus -65.0 kcal/mol for the conventional AblT315I inhibitor ponatinib. Cell proliferation assays showed SISB-A1 to have a GI50 of 164.0 nM against the ABL-T315I stable cell line, whereas imatinib had a GI50 of 5035 nM. The IC50 value obtained for SISB-A1 against the AblT315I kinase was 197.9 nM. The results indicate SISB-A1 to have a notable ability to bind the catalytic domain of the AblT315I mutant kinase and effectively suppress its activity, thereby surpassing the associated resistance to imatinib. Continued advancement of this lead compound has the potential to yield innovative therapeutics for imatinib-resistant CML.

A comprehensive analysis of cell-autonomous and non-cell-autonomous regulation of myeloid leukemic cells: The prospect of developing novel niche-targeting therapies

Leukemic cells (LCs) arise from the hematopoietic stem/and progenitor cells (HSCs/HSPCs) and utilize cues from the bone marrow microenvironment (BMM) for their regulation in the same way as their normal HSC counterparts. Mesenchymal stromal cells (MSCs), a vital component of the BMM promote leukemogenesis by creating a protective and immune-tolerant microenvironment that can support the survival of LCs, helping them escape chemotherapy, thereby resulting in the relapse of leukemia. Conversely, MSCs also induce apoptosis in the LCs and inhibit their proliferation by interfering with their self-renewal potential. This review discusses the work done so far on cell-autonomous (intrinsic) and MSCs-mediated non-cell-autonomous (extrinsic) regulation of myeloid leukemia with a special focus on the need to investigate the extrinsic regulation of myeloid leukemia to understand the contrasting role of MSCs in leukemogenesis. These mechanisms could be exploited to formulate novel therapeutic strategies that specifically target the leukemic microenvironment.

Reverse Transcription Can Critically Impact the Diagnostic Outcome of BCR::ABL1 Quantitative Real-Time RT-PCR

Reverse transcriptases (RT) are essential tools in BCR::ABL1 fusion transcript monitoring in chronic myeloid leukemia (CML). The RT type and cDNA priming method may impair the stoichiometry of cDNA synthesis, thereby potentially introducing a bias in BCR::ABL1 qRT-PCR data. Using the Acrometrix™ BCR::ABL1 reference panel and 37 clinical specimens, we have comparatively investigated the performance of the RTs MLV and SuperScript IV with random hexamer vs. target-specific priming. Quantitative RT-PCR results identified the priming type and RT type as major factors for diagnostic data variation, mainly due to the different efficacies of processing BCR::ABL1 low-copy-numbers (<50) compared to GUSB or ABL1 high-copy targets. The impairment of SuperScript IV in processing low- and high-copy-number RNA targets equally was not reflected by the diagnostically relevant Log (BCR::ABL1/GUSB%) values. Therefore, the correct representation of housekeeping and BCR::ABL1 target genes should have priority when aiming at as high a number of housekeeping gene copies as possible. Our data suggest that for improving BCR::ABL1 assay sensitivity, increased RNA/cDNA amounts and the use of distinct RT/priming combinations are advantageous. However, for inter-laboratory harmonization, the proper conversion factor according to the CML international standard (IS) has to be reevaluated each time the grade of RT is changed.

Outcomes of allogeneic or autologous stem cell transplantation followed by maintenance chemotherapy in adult patient with B-ALL in CR1 with no detectable minimal residual disease

Autologous haematopoietic stem cell transplantation (auto-HSCT) as a treatment for B-cell acute lymphoblastic leukaemia (B-ALL) has been rigorously debated in recent years. We retrospectively analysed the outcomes of 355 adult patients with B-ALL in first complete remission who had received auto-HSCT or allogeneic HSCT (allo-HSCT) in our centre. The treatment efficacy was evaluated from a model stratified on the risk classification and minimal residue disease (MRD) status after three chemotherapy cycles. Auto-HSCT demonstrated comparable 3-year overall survival (OS) (72.7% vs. 68.5%, p = 0.441) and leukaemia-free survival rates (62.8% vs. 56.1%, p = 0.383) compared to allo-HSCT for patients with negative MRD, while the advantage of lower non-relapse mortality (1.5% vs. 25.1%, p < 0.001) was offset by a higher cumulative incidence of relapse (CIR) rates (35.7% vs. 18.9%, p = 0.018), especially in high-risk patients. For patients at high risk and with positive MRD, there was a lower trend of 3-year OS (50.0% vs. 66.0%, p = 0.078) and significantly higher CIR rates (71.4% vs. 39.1%, p = 0.018) in auto-HSCT. However, no significant interaction was observed in the tests. In conclusion, auto-HSCT appears to be an attractive treatment for patients with negative MRD after three chemotherapy cycles. For MRD-positive patients, allo-HSCT may be a more effective treatment.

Basic and clinical study of efficacy and adverse effects of flumatinib in Ph+ ALL

Objective: To investigate the efficacy and safety of chemotherapy in treating Ph+ ALL based on flumatinib. Methods: The clinical data of 29 patients with Ph+ ALL receiving flumatinib-based chemotherapy in Sichuan Provincial People's Hospital from January 2020 to January 2023 were collected for analysis, with the concentrations of TKI in the peripheral blood, bone marrow, and cerebrospinal fluid of some patients monitored, Cytological experiments on SUP-B15 were conducted in a Ph+ ALL cell line. Results: A total of 29 patients were enrolled, showing the induced CR, 3-month CR, and 6-month CR rates of 96.3%, 87.5%, and 86.7%, respectively after flumatinib-based chemotherapy. The negative conversion ratio of MRD was 82.6%, 91.3%, and 95.6% in 1, 2, and 3 months after treatment, respectively, with 4.3% of patients failing the conversion in 3 months after treatment. The rates of MMR were 73.9%, 87.5%, and 93.3% in 1, 3, and 6 months after treatment, and CMR of 52.2%, 62.5%, and 73.3%, respectively. Among the 29 patients, 11 (37.9%) received transplant and the continuous flumatinib for 1 year after transplantation. The deep remission was maintained in all patients up to the time of follow-up, with the median follow-up of 12 months (1-33 months), progression-free survival (PFS) of 11 months (1-33 months), and median overall survival (OS) of 12 months (1-33 months). The adverse reactions mainly referred to myelosuppression, liver insufficiency and infection that were generally tolerable. In terms of blood concentration, the concentration of flumatinib was ordered as bone marrow > serum > cerebrospinal fluid in Ph+ ALL bone marrow. In contrast, the concentration of dasatinib and imatinib was ordered as serum > bone marrow > cerebrospinal fluid. At the same time, flumatinib has a high probability to cross the blood-brain barrier, while the concentration of cerebrospinal fluid in the patients using Dasatinib was lower compared to the lower limit of detection in this study. Compared with Imatinib and Dasatinib, flumatinib exerted the most potent inhibitory effect on Ph+ ALL cell lines according to pharmacodynamic analysis of SUP-B15 cells. Conclusion: Flumatinib combined with chemotherapy could achieve good efficacy and safety in treating Ph+ ALL, with flumatinib in a high probability of crossing the blood-brain barrier. Flumatinib could be a superior choice to Dasatinib and Imatinib in cell experiments.

Asciminib vs bosutinib in chronic-phase chronic myeloid leukemia previously treated with at least two tyrosine kinase inhibitors: longer-term follow-up of ASCEMBL

Asciminib, the first BCR::ABL1 inhibitor that Specifically Targets the ABL Myristoyl Pocket (STAMP), is approved worldwide for the treatment of adults with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase (CML-CP) treated with ≥2 prior tyrosine kinase inhibitors (TKIs). In ASCEMBL, patients with CML-CP treated with ≥2 prior TKIs were randomized (stratified by baseline major cytogenetic response [MCyR]) 2:1 to asciminib 40 mg twice daily or bosutinib 500 mg once daily. Consistent with previously published primary analysis results, after a median follow-up of 2.3 years, asciminib continued to demonstrate superior efficacy and better safety and tolerability than bosutinib. The major molecular response (MMR) rate at week 96 (key secondary endpoint) was 37.6% with asciminib vs 15.8% with bosutinib; the MMR rate difference between the arms, after adjusting for baseline MCyR, was 21.7% (95% CI, 10.53-32.95; two-sided p = 0.001). Fewer grade ≥3 adverse events (AEs) (56.4% vs 68.4%) and AEs leading to treatment discontinuation (7.7% vs 26.3%) occurred with asciminib than with bosutinib. A higher proportion of patients on asciminib than bosutinib remained on treatment and continued to derive benefit over time, supporting asciminib as a standard of care for patients with CML-CP previously treated with ≥2 TKIs.

Jak2/STAT6/c-Myc pathway is vital to the pathogenicity of Philadelphia-positive acute lymphoblastic leukemia caused by P190BCR-ABL

BACKGROUND

The Philadelphia chromosome encodes the BCR-ABL fusion protein, which has two primary subtypes, P210 and P190. P210 and P190 cause Philadelphia-positive chronic myeloid leukemia (Ph+ CML) and Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL), respectively. The Ph+ ALL is more malignant than Ph+ CML in disease phenotype and progression. This implies the key pathogenic molecules and regulatory mechanisms caused by BCR-ABL in two types of leukemia are different. It is reported that STAT6 was significantly activated only in P190 transformed cells. However, the potential role and the mechanism of STAT6 activation in Ph+ ALL and its activation mechanism by P190 are still unknown.

METHODS

The protein and mRNA levels of STAT6, c-Myc, and other molecules were measured by western blot and quantitative real-time PCR. The STAT6 inhibitor AS1517499 was used to specifically inhibit p-STAT6. The effect of p-STAT6 inhibition on Ph+ CML and Ph+ ALL cells was identified by CCK-8 and FCM assay. Dual luciferase reporter and ChIP assay were performed to confirm the direct binding between STAT6 and c-Myc. The impact of STAT6 inhibition on tumor progression was detected in Ph+ CML and Ph+ ALL mouse models.

RESULTS

Our results demonstrated that P210 induced CML-like disease, and P190 caused the more malignant ALL-like disease in mouse models. STAT6 was activated in P190 cell lines but not in P210 cell lines. Inhibition of STAT6 suppressed the malignancy of Ph+ ALL in vitro and in vivo, whereas it had little effect on Ph+ CML. We confirmed that p-STAT6 regulated the transcription of c-Myc, and STAT6 was phosphorylated by p-Jak2 in P190 cell lines, which accounted for the discrepant expression of p-STAT6 in P190 and P210 cell lines. STAT6 inhibition synergized with imatinib in Ph+ ALL cells.

CONCLUSIONS

Our study suggests that STAT6 activation plays an essential role in the development of Ph+ ALL and may be a potential therapeutic target in Ph+ ALL. Video abstract.

How I treat with maintenance therapy after allogeneic HCT

Disease relapse is the leading cause of failure for patients receiving allogeneic hematopoietic cell transplantation (allo-HCT). Maintenance therapy administered after allo-HCT is a promising strategy to reduce the incidence of relapse and enhance the curative potential of allo-HCT. Research investigations and clinical applications of this approach have greatly increased in recent years, with an expanding number of available therapeutic agents to introduce in the posttransplant setting. However, many questions and challenges remain regarding the feasibility and clinical impact of maintenance. In this article, we present four common case scenarios addressing select available therapeutic agents as a framework to review published data and ongoing studies and describe our current standard practice in the rapidly evolving field of maintenance therapy after allo-HCT.

Molecular Mechanisms of Tyrosine Kinase Inhibitor Resistance in Chronic Myeloid Leukemia

The hematopoietic neoplasm chronic myeloid leukemia (CML) is a rare disease caused by chromosomal reciprocal translocation t(9;22)(q34:q11) with subsequent formation of the BCR-ABL1 fusion gene. This fusion gene encodes a constitutively active tyrosine kinase, which results in malignant transformation of the cells. Since 2001, CML can be effectively treated using tyrosine kinase inhibitors (TKIs) such as imatinib, which prevent phosphorylation of downstream targets by blockade of the BCR-ABL kinase. Due to its tremendous success, this treatment became the role model of targeted therapy in precision oncology. Here, we review the mechanisms of TKI resistance focusing on BCR-ABL1-dependent and -independent mechanisms. These include the genomics of the BCR-ABL1, TKI metabolism and transport and alternative signaling pathways.

Next-generation sequencing-based analysis to assess the pattern of relapse in patients with Philadelphia-positive acute lymphoblastic leukemia

In this study, we performed serial monitoring using targeted DNA sequencing to identify genetic alterations in adults with Philadelphia-positive acute lymphoblastic leukemia (Ph-ALL). Deep sequencing was performed by targeting the coding regions of 45 genes with recurrent driver mutations and 1129 single nucleotide polymorphism sites. Of the 43 patients that we examined, at least one case of genetic alterations was detected in 38 (88%) of the 43 patients at diagnosis (somatic mutations in 10 patients [23%] and copy number aberrations [CNA] in 36 patients [84%]). The most frequently detected CNA lesions were in IKZF1 (n = 25, 58%) and the most frequently mutated gene was SETD2 (n = 5). At least one genetic abnormality (loss, gain, or persistence) was observed in all the samples obtained at relapse that were available for analysis (n = 15), compared with the samples obtained at diagnosis (disappearance of any previously detected genetic alterations: 11 patients [73%]; new genetic abnormalities: nine patients [60%]; and persistent genetic abnormalities: eight patients [53%]]. The most frequently deleted lesions were in IKZF1 (n = 9, 60%), and the most frequently mutated gene was ABL1 (eight patients, 53%). Our data indicate that leukemic progression may be associated with complex genetic alterations in Ph-ALL during the course of treatment.

Pharmacokinetics, Bioequivalence, and Safety Studies of a Generic Selective Tyrosine Kinase Inhibitor Nilotinib Capsule Versus a Branded Product in Healthy Chinese Volunteers

Nilotinib, a second-generation tyrosine kinase inhibitor (TKI), has been approved in the United States and Europe as a treatment for patients with newly diagnosed chronic myeloid leukemia (CML)-chronic phase (CP) and patients with CML-CP or chronic myeloid leukemia-accelerated phase (CML-AP) who are resistant or intolerant to imatinib (a first-generation TKI). This study compared the bioequivalence and safety of the test nilotinib capsule and reference nilotinib capsule (Tasigna, Novartis) in healthy Chinese volunteers under fasting conditions for marketing authorization in China. The results of the study are reported for the first time. This was a single-dose, randomized, open-label, two-period, and cross-over study. Thirty healthy volunteers were randomly assigned to receive a single dose of a 200-mg test or reference capsule under fasting conditions in each period with a 10-day washout. Plasma samples were analyzed with liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were calculated with WinNonlin software. The geometric mean ratio and the corresponding 90% confidence intervals of C_max , AUC_0-t , and AUC_0-∞ for nilotinib between the two fixed-dose combination formulations were within the bioequivalence acceptance range of 80%-125%, therefore the generic and branded formulations were bioequivalent in healthy Chinese volunteers.

Design, semi-synthesis and examination of new gypsogenin derivatives against leukemia via Abl tyrosine kinase inhibition and apoptosis induction

Chronic myelogenous leukemia (CML) is characterized by Philadelphia translocation arising from Bcr-Abl fusion gene, which encodes abnormal oncoprotein showing tyrosine kinase (TK) function. Certain mutations in kinase domain, off-target effects and resistance problems of current TK inhibitors require the discovery of novel Abl TK inhibitors. For this purpose, herein, we synthesized new gypsogenin derivatives (6a-l) and evaluated their anticancer effects towards CML cells along with healthy cell line and different leukemic cells. Among these compounds, compound 6l was found as the most active anti-leukemic agent against K562 CML cells compared to imatinib exerting less cytotoxicity towards PBMCs (healthy). This compound also revealed significant anti-leukemic effects against Jurkat cell line. Besides, compound 6l enhanced apoptosis in CML cells with 52.4 % when compared with imatinib (61.8 %) and inhibited Abl TK significantly with an IC₅₀ value of 13.04 ± 2.48 μM in a large panel of kinases accentuating Abl TK-mediated apoptosis of compound 6l in CML cells. Molecular docking outcomes showed that compound 6l formed mainly crucial interactions in the ATP-binding cleft of Abl TK similar to that of imatinib. Ultimately, in silico pharmacokinetic evaluation of compound 6l indicated that this compound was endowed with anti-leukemic drug candidate features.

An easy-to-use nomogram predicting overall survival of adult acute lymphoblastic leukemia

Adult acute lymphoblastic leukemia (ALL) is heterogeneous both biologically and clinically. The outcomes of ALL have been improved with the application of children-like regimens and novel agents including immune therapy in young adults. The refractory to therapy and relapse of ALL have occurred in most adult cases. Factors affecting the prognosis of ALL include age and white blood cell (WBC) count at diagnosis. The clinical implications of genetic biomarkers, including chromosome translocation and gene mutation, have been explored in ALL. The interactions of these factors on the prediction of prognosis have not been evaluated in adult ALL. A prognostic model based on clinical and genetic abnormalities is necessary for clinical practice in the management of adult ALL. The newly diagnosed adult ALL patients were divided into the training and the validation cohort at 7:3 ratio. Factors associated with overall survival (OS) were assessed by univariate/multivariate Cox regression analyses and a signature score was assigned to each independent factor. A nomogram based on the signature score was developed and validated. The receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA) were used to assess the performance of the nomogram model. This study included a total of 229 newly diagnosed ALL patients. Five independent variables including age, WBC, bone marrow (BM) blasts, MLL rearrangement, and ICT gene mutations (carried any positive mutation of IKZF1, CREBBP and TP53) were identified as independent adverse factors for OS evaluated by the univariate, Kaplan-Meier survival and multivariate Cox regression analyses. A prognostic nomogram was built based on these factors. The areas under the ROC curve and calibration curve showed good accuracy between the predicted and observed values. The DCA curve showed that the performance of our model was superior to current risk factors. A nomogram was developed and validated based on the clinical and laboratory factors in newly diagnosed ALL patients. This model is effective to predict the overall survival of adult ALL. It is a simple and easy-to-use model that could efficiently predict the prognosis of adult ALL and is useful for decision making of treatment.

Detection of kinase domain mutations in BCR::ABL1 leukemia by ultra-deep sequencing of genomic DNA

The screening of the BCR::ABL1 kinase domain (KD) mutation has become a routine analysis in case of warning/failure for chronic myeloid leukemia (CML) and B-cell precursor acute lymphoblastic leukemia (ALL) Philadelphia (Ph)-positive patients. In this study, we present a novel DNA-based next-generation sequencing (NGS) methodology for KD ABL1 mutation detection and monitoring with a 1.0E-4 sensitivity. This approach was validated with a well-stablished RNA-based nested NGS method. The correlation of both techniques for the quantification of ABL1 mutations was high (Pearson r = 0.858, p < 0.001), offering DNA-DeepNGS a sensitivity of 92% and specificity of 82%. The clinical impact was studied in a cohort of 129 patients (n = 67 for CML and n = 62 for B-ALL patients). A total of 162 samples (n = 86 CML and n = 76 B-ALL) were studied. Of them, 27 out of 86 harbored mutations (6 in warning and 21 in failure) for CML, and 13 out of 76 (2 diagnostic and 11 relapse samples) did in B-ALL patients. In addition, in four cases were detected mutation despite BCR::ABL1 < 1%. In conclusion, we were able to detect KD ABL1 mutations with a 1.0E-4 sensitivity by NGS using DNA as starting material even in patients with low levels of disease.

Mechanisms of Resistance and Implications for Treatment Strategies in Chronic Myeloid Leukaemia

Simple Summary

Chronic myeloid leukaemia (CML) is a type of blood cancer that is currently well-managed with drugs that target cancer-causing proteins. However, a significant proportion of CML patients do not respond to those drug treatments or relapse when they stop those drugs because the cancer cells in those patients stop relying on that protein and instead develop a new way to survive. Therefore, new treatment strategies may be necessary for those patients. In this review, we discuss those additional survival pathways and outline combination treatment strategies to increase responses and clinical outcomes, improving the lives of CML patients.

Abstract

Tyrosine kinase inhibitors (TKIs) have revolutionised the management of chronic myeloid leukaemia (CML), with the disease now having a five-year survival rate over 80%. The primary focus in the treatment of CML has been on improving the specificity and potency of TKIs to inhibit the activation of the BCR::ABL1 kinase and/or overcoming resistance driven by mutations in the BCR::ABL1 oncogene. However, this approach may be limited in a significant proportion of patients who develop TKI resistance despite the effective inhibition of BCR::ABL1. These patients may require novel therapeutic strategies that target both BCR::ABL1-dependent and BCR::ABL1-independent mechanisms of resistance. The combination treatment strategies that target alternative survival signalling, which may contribute towards BCR::ABL1-independent resistance, could be a successful strategy for eradicating residual leukaemic cells and consequently increasing the response rate in CML patients.

Mapping incidence and mortality of leukemia and its subtypes in 21 world regions in last three decades and projections to 2030

This study examines the burden of leukemia and its subtypes at the global, regional, and national levels in 21 world regions and 204 countries in the last three decades. The estimates of incidence, deaths, and age-standardized rates of leukemia for 21 regions and 204 countries for 1990-2019 were extracted from the Global Burden of Disease 2019 study. Average annual percentage change in 1990-2019 for 21 regions was utilized for projecting leukemia burden in 2030. Globally, there were 643,579 [586,980-699,729] incident cases and 334,592 [306,818-360,214] deaths in 2019 due to leukemia, up from 474,924 [388,559-560,550] cases and 263,263 [233,664-298,696] deaths in 1990. Between 1990 and 2019, the age-standardized incidence rate (ASIR) decreased from 9.6 [8.1-11.0] in 1990 to 8.2 [7.5-8.9] per 100,000 person-years in 2019, and the age-standardized mortality rate (ASMR) decreased from 5.8/100,000 [5.2-6.4] in 1990 to 4.3/100,000 [3.9-4.6] in 2019. Between 1990 and 2019, the ASIR decreased in majority of regions except Western Europe and high-income Asia Pacific, whereas the ASMR decreased in all 21 regions. In 2019, country-wise, the ASIR varied from 3.0/100,000 [2.3-3.7] in Palau to 35.1/100,000 [26.4-47.2] in San Marino and the ASMR spanned from 2.3/100,000 [1.7-2.8] in San Marino to 15.8/100,000 [12.0-20.4] in Syria. As per our projections, globally, there will be 720,168 incident cases and 367,804 deaths due to leukemia in 2030. Substantial improvements have been witnessed in leukemia mortality rates in all regions, especially high-income regions and countries. Health care policies focusing on diagnostic improvements, cancer registration, and newer therapeutics at reduced cost or with insurance coverage are needed in low and middle-income countries.

Primary Testicular and Cutaneous Philadelphia Chromosome Positive B-Cell Lymphoblastic Lymphoma: A Rare Case and Review

Philadelphia chromosome positive B cell lymphoblastic lymphoma (Ph+ B-LBL) is an extremely rare disease. We report a 27-year-old patient diagnosed with primary testicular and cutaneous Ph+ B-LBL without bone marrow involvement. The CCCG-LBL-2016 regimen (https://clinicaltrials.gov/ct2/show/NCT02845882) was initially administered due to the fast pathological diagnosis as B-LBL that was first obtained. To identify potential therapeutic targets, RNA sequencing (RNAseq) was also performed on lymph node specimens as a part of the routine diagnostic workup in our center. Unexpectedly, IKZF1 deletions and BCR-ABL1 fusion transcripts were detected. Based on these results, we retrospectively performed fluorescence in situ hybridization (FISH) for BCR/ABL1 rearrangements in the same lymph node specimen, and a 70% positive signal was detected. The patient subsequently received the CCCG-LBL-2016 protocol combined with the BCR-ABL tyrosine kinase inhibitor (TKI) dasatinib, along with prophylactic intrathecal infusion. Then, the patient underwent TBI-based haploidentical (haplo) allogeneic hematopoietic stem cell transplantation (haplo-allo-HSCT) as consolidation following the achievement of remission and continued taking dasatinib as maintenance therapy. The patient was still in complete remission 1 year after diagnosis. This case indicates that the detection of potential molecular targets, especially those targets that can be pharmacologically treated, such as BCR/ABL1 fusion transcripts, is of important value to both LBL diagnosis and therapeutic strategy choices. FISH, reverse transcriptase polymerase chain reaction (RT-PCR) and/or RNAseq should be routinely carried out in lymphoma specimens to depict its genetic landscape for the further execution of a precise therapy strategy.

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Genetic Biomarkers and Their Clinical Implications in B-Cell Acute Lymphoblastic Leukemia in Children

Acute lymphoblastic leukemia (ALL) is a heterogeneous group of hematologic malignancies characterized by abnormal proliferation of immature lymphoid cells. It is the most commonly diagnosed childhood cancer with an almost 80% cure rate. Despite favorable survival rates in the pediatric population, a significant number of patients develop resistance to therapy, resulting in poor prognosis. ALL is a heterogeneous disease at the genetic level, but the intensive development of sequencing in the last decade has made it possible to broaden the study of genomic changes. New technologies allow us to detect molecular changes such as point mutations or to characterize epigenetic or proteomic profiles. This process made it possible to identify new subtypes of this disease characterized by constellations of genetic alterations, including chromosome changes, sequence mutations, and DNA copy number alterations. These genetic abnormalities are used as diagnostic, prognostic and predictive biomarkers that play an important role in earlier disease detection, more accurate risk stratification, and treatment. Identification of new ALL biomarkers, and thus a greater understanding of their molecular basis, will lead to better monitoring of the course of the disease. In this article, we provide an overview of the latest information on genomic alterations found in childhood ALL and discuss their impact on patients' clinical outcomes.

Patient preferences for frontline therapies for Philadelphia chromosome-positive acute lymphoblastic leukemia: a discrete choice experiment

Aim: We examined the preferences of adults with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) for benefits and risks of tyrosine kinase inhibitors combined with chemotherapy for first-line treatment. Methods: In a discrete choice experiment, 201 patients chose between hypothetical treatment alternatives with varied levels of remission duration and overall survival (OS), and risks of major cardiovascular (CV) events and myelosuppression. Results: Although OS was the most important attribute to patients with Ph+ ALL, they were willing to tolerate a 2.9% increase in CV risk for 1 additional month of OS. Older patients (>59 years) and patients not in remission were less likely to tolerate increased CV risk. Conclusion: Preferences and risk tolerance varied between patients, highlighting the importance of shared decision making when selecting treatments for Ph+ ALL.

Genetic correlates in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia treated with Hyper-CVAD plus dasatinib or ponatinib

Recurring genetic abnormalities have been identified in Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL). Among them, IKZF1 deletion was associated with poor prognosis in patients treated with imatinib-based or dasatinib-based regimens. However, the molecular determinants for clinical outcomes in ponatinib-treated patients remain unknown. We systematically analyzed genetic alterations in adults with Ph-positive ALL uniformly treated in clinical trials with dasatinib-based regimens or a ponatinib-based regimen and investigated the molecular determinants for treatment outcomes using pretreatment specimens collected from adults with Ph-positive ALL treated with Hyper-CVAD plus dasatinib or ponatinib. DNA sequencing and SNP microarray were performed and recurrent genetic abnormalities were found in 84% of the patients, among whom IKZF1 deletion was most frequently detected (60%). IKZF1 deletion frequently co-occurred with other copy-number abnormalities (IKZF1^plus, 46%) and was significantly associated with unfavorable overall survival (OS) (false discovery rate < 0.1) and increased cumulative incidence of relapse (p = 0.01). In a multivariate analysis, dasatinib therapy, lack of achievement of 3-month complete molecular response, and the presence of IKZF1^plus status were significantly associated with poor OS. The differential impact of IKZF1^plus was largely restricted to patients given Hyper-CVAD plus ponatinib; dasatinib-based regimens had unfavorable outcomes regardless of the molecular abnormalities.

hnRNPK/Beclin1 signaling regulates autophagy to promote imatinib resistance in Philadelphia chromosome-positive acute lymphoblastic leukemia cells

BACKGROUND

This study sought to clarify the role of hnRNPK as a regulator of imatinib resistance in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL).

METHODS

The expression of hnRNPK was assessed in Ph+ ALL leukemia cells in vitro and in vivo, while imatinib susceptibility was assessed via CCK-8 assay. In cells in which hnRNPK levels had or had not been modulated, LC3Ⅰ/Ⅱ and mTOR/p-ERK/Beclin1levels were assessed via western blotting, while electron microscopy was used to evaluate autophagic vacuole formation. Interactions between hnRNPK and Beclin1 were assessed through an RNA binding protein immunoprecipitation assay.

RESULTS

Imatinib-resistant Ph+ ALL cell lines and patient bone marrow samples exhibited significant hnRNPK overexpression. The knockdown of hnRNPK increased the imatinib sensitivity of these tumor cells and decreased in vivo tumor burden in a xenograft model system as evidenced by a reduction in tumor volume. Levels of LC3Ⅰ/Ⅱand Beclin1, but not p-ERK and mTOR, were consistent with the regulatory activity of hnRNPK.Electronmicroscopy revealed that imatinib-resistant cells harbored significantly more autophagic vacuoles relative to wild-type cells, while hnRNPK knockdown reduced the number of these vacuoles. In an RNA binding protein immunoprecipitation assay, anti-hnRNPK was able to precipitate the Beclin1 mRNA.

CONCLUSIONS

These results suggest that the hnRNPK/Beclin1 signaling pathway may play a role in shaping imatinib resistance in Ph+ ALL cells.

Development of Asciminib, a Novel Allosteric Inhibitor of BCR-ABL1

Chronic myeloid leukemia (CML) is driven by a translocation event between chromosomes 9 and 22, leading to the formation of a constitutively active BCR-ABL1 oncoprotein. Approved tyrosine kinase inhibitors (TKIs) for CML inhibit BCR-ABL1 by competitively targeting its adenosine triphosphate (ATP)-binding site, which significantly improves patient outcomes. However, resistance to and intolerance of TKIs remains a clinical challenge. Asciminib is a promising investigational agent in development that allosterically targets BCR-ABL1 in a non-ATP-competitive manner. It binds to the ABL1 myristoyl-binding pocket and is effective against most ABL1 kinase domain mutations that confer resistance to ATP-competitive TKIs, including the T315I mutation. This review discusses unmet needs in the current CML treatment landscape, reports clinical data from asciminib trials that support the use of single-agent asciminib as third-line therapy and beyond, and explores the potential benefit of asciminib in combination with approved TKIs in earlier lines.

Overcoming Resistance to Kinase Inhibitors: The Paradigm of Chronic Myeloid Leukemia

Protein kinases (PKs) play crucial roles in cellular proliferation and survival, hence their deregulation is a common event in the pathogenesis of solid and hematologic malignancies. Targeting PKs has been a promising strategy in cancer treatment, and there are now a variety of approved anticancer drugs targeting PKs. However, the phenomenon of resistance remains an obstacle to be addressed and overcoming resistance is a goal to be achieved. Chronic myeloid leukemia (CML) is the first as well as one of the best examples of a cancer that can be targeted by molecular therapy; hence, it can be used as a model disease for other cancers. This review aims to summarize up-to-date knowledge on the main mechanisms implicated in resistance to PK inhibitory therapies and to outline the main strategies that are being explored to overcome resistance. The importance of molecular diagnostics and disease monitoring in counteracting resistance will also be discussed.

Targeting SOS1 overcomes imatinib resistance with BCR-ABL independence through uptake transporter SLC22A4 in CML

Resistance to the BCR-ABL inhibitor imatinib mesylate poses a major problem for the treatment of chronic myeloid leukemia. Imatinib resistance often results from a secondary mutation in BCR-ABL that interferes with drug binding. However, sometimes there is no mutation in BCR-ABL, and the basis of such BCR-ABL-independent imatinib mesylate resistance remains to be elucidated. SOS1, a guanine nucleotide exchange factor for Ras protein, affects drug sensitivity and resistance to imatinib. The depletion of SOS1 markedly inhibits cell growth either in vitro or in vivo and significantly increases the sensitivity of chronic myeloid leukemia cells to imatinib. Furthermore, LC-MS/MS and RNA-seq assays reveal that SOS1 negatively regulates the expression of SLC22A4, a member of the carnitine/organic cation transporter family, which mediates the active uptake of imatinib into chronic myeloid leukemia cells. HPLC assay confirms that intracellular accumulation of imatinib is accompanied by upregulation of SLC22A4 through SOS1 inhibition in both sensitive and resistant chronic myeloid leukemia cells. BAY-293, an inhibitor of SOS1/Ras, was found to depress proliferation and colony formation in chronic myeloid leukemia cells with resistance and BCR-ABL independence. Altogether these findings indicate that targeting SOS1 inhibition promotes imatinib sensitivity and overcomes resistance with BCR-ABL independence by SLC22A4-mediated uptake transport.

Extramedullary Hematopoiesis of the Liver and Spleen

Hematopoiesis is the formation of blood cellular components and, consequently, immune cells. In a more complete definition, this process refers to the formation, growth, maturation, and specialization of blood cells, from the hematopoietic stem cell, through the hematopoietic progenitor cells, to the s pecialized blood cells. This process is tightly regulated by several elements of the bone marrow microenvironment, such as growth factors, transcription factors, and cytokines. During embryonic and fetal development, hematopoiesis takes place in different organs: the yolk sac, the aorta–gonad mesonephros region, the lymph nodes, and not lastly, the fetal liver and the spleen. In the current review, we describe extramedullary hematopoiesis of the spleen and liver, with an emphasis on myeloproliferative conditions.

Description of PTPRG genetic variants identified in a cohort of Chronic Myeloid Leukemia patients and their ability to influence response to Tyrosine kinase Inhibitors

Tyrosine kinase inhibitors (TKIs) have remarkably transformed Ph+ chronic myeloid leukemia (CML) management; however, TKI resistance remains a major clinical challenge. Mutations in BCR-ABL1 are well studied but fail to explain 20-40% of resistant cases, suggesting the activation of alternative, BCR-ABL1-independent pathways. Protein Tyrosine Phosphatase Receptor Gamma (PTPRG), a tumor suppressor, was found to be well expressed in CML patients responsive to TKIs and down-regulated in resistant patients. In this study, we aimed to identify genetic variants in PTPRG that could potentially modulate TKIs response in CML patients. DNA was extracted from peripheral blood samples collected from two CML cohorts (Qatar and Italy) and targeted exome sequencing was performed. Among 31 CML patients, six were TKI-responders and 25 were TKI-resistant. Sequencing identified ten variants, seven were annotated and three were novel SNPs (c.1602_1603insC, c.85+86delC, and c.2289-129delA). Among them, five variants were identified in 15 resistant cases. Of these, one novel exon variant (c.1602_1603insC), c.841-29C>T (rs199917960) and c.1378-224A>G (rs2063204) were found to be significantly different between the resistant cases compared to responders. Our findings suggest that PTPRG variants may act as an indirect resistance mechanism of BCR-ABL1 to affect TKI treatment.

Comparison of allogeneic hematopoietic stem cell transplantation and TKI combined with chemotherapy for adult philadelphia chromosome positive acute lymphoblastic leukemia: a systematic review and meta-analysis

OBJECTIVE

This study seeks to clarify whether allogeneic hematopoietic stem cell transplantation (allo-HSCT) is necessary for adult patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) in post-remission based on a comparison with tyrosine kinase inhibitor (TKI) combined with chemotherapy.

METHODS

We searched the Pubmed, Embase, and Web of Science databases and limited the date range for the studies from January 2010 to August 2020. A hazard ratio (HR) with a 95% confidence interval (CI) was employed to assess overall survival (OS) and relapse-free survival (RFS), and an odds ratio (OR) with a 95% CI was used to evaluate the ratio of non-relapsed mortality (NRM) and non-relapsed survival (NRS). All analyses were conducted with Stata software 16.0 and Revman 5.3.

RESULTS

Fifteen studies, totaling 959 patients, were included in our analysis. Among those patients, 473 underwent allo-HSCT, and 486 received TKI plus chemotherapy. The pooled results showed no difference in OS between outcomes for patients receiving TKI plus chemotherapy and those treated with allo-HSCT (HR = 0.76, 95% CI [0.51-1.12], p = 0.16). Patients undergoing allo-HSCT did better than those receiving TKI plus chemotherapy regarding RFS (HR = 0.48, 95% CI [0.37-0.63], p = 0.00), and NRS (OR = 2.64, 95% CI [1.25-5.57], p = 0.00). The NRM rate of the TKI plus chemotherapy group was significantly lower than the allo-HSCT group (OR = 2.33, 95% CI [1.51-3.59], p = 0.00).

CONCLUSION

TKI combined with chemotherapy can be considered a post-remission treatment option for adult Ph+ ALL patients who are ineligible for allo-HSCT. However, more prospective studies with large sample sizes should be carried out in the future.

High Expression of PKM2 Was Associated with the Poor Prognosis of Acute Leukemia

Purpose

To explore the clinical significance of plasma pyruvate kinase M2 (PKM2) in assessing the incidence and prognosis of acute leukemia.

Methods

Plasma samples from 56 acute myeloid leukemia (AML) patients, 40 acute lymphoblastic leukemia (ALL) patients, and 66 plasma samples from healthy individuals were collected. The level of plasma PKM2 was detected by enzyme-linked immunosorbent assay. The clinical significance of PKM2 in acute leukemia was assessed by analyzing receiver operating characteristic and survival curves.

Results

The plasma levels of PKM2 in AML or ALL patients were significantly higher than those in healthy individuals, respectively. PKM2 can be used as a potential diagnostic index with the AUC of 0.827 for AML and 0.837 for ALL. The level of plasma PKM2 in ALL patients with a BCR/ABL-positive genotype was significantly higher than that in patients with a BCR/ABL-negative genotype (p<0.05). The event-free survival and the overall survival of acute leukemia patients with higher PKM2 expression was worse than those with lower PKM2 expression.

Conclusion

This study showed that higher levels of PKM2 was negatively correlated with the prognosis of acute leukemia. Therefore, PKM2 can be used as a potential index to assess the incidence and prognosis of acute leukemia.

Investigation on the interaction behavior of afatinib, dasatinib, and imatinib docked to the BCR-ABL protein

Chronic myeloid leukemia (CML) is a pathological condition associated with the uncontrolled proliferation of white blood cells and respective loss of function. Imatinib was the first drug that could effectively treat this condition, but its use is hindered by the development of mutations of the BCR-ABL protein, which are the cause of resistance. Therefore, dasatinib and afatinib present similarities that can be explored to discover new molecules capable of overcoming the effects of imatinib. Afatinib exhibited electronic and docking behavior, indicating that a replacement with some minor modifications could design a new potential inhibitor. The amide group in each candidate is clearly of pharmacophoric importance, and it needs to concentrate a negative region. Sulfur group presents a good pharmacophoric profile, which was shown by dasatinib results, adding to the influence of the Met318 residue in the target protein active site configuration. This behavior suggests that the sulfur atom and other fragments that have an affinity for the methionine sidechain may provide a significant positive effect when present in TKI molecules such as afatinib or dasatinib.

Nilotinib vs. imatinib in Japanese patients with newly diagnosed chronic myeloid leukemia in chronic phase: 10-year follow‑up of the Japanese subgroup of the randomized ENESTnd trial

In the 10-year analysis of Japanese patients with newly diagnosed CML-CP in the ENESTnd trial, nilotinib yielded higher cumulative response rates. There were no new occurrences of disease progression or deaths since the 5-year analysis. Cumulative 10-year rates of MMR and MR^4.5 were higher in the nilotinib arms [300 mg twice daily (BID), 86.2% and 69.0%, respectively; 400 mg BID, 78.3% and 69.6%, respectively] than the imatinib arm (400 mg once daily, 60.0% and 48.0%, respectively). Nasopharyngitis (85.7%, 77.3%, 79.2%), rash (50.0%, 68.2%, 37.5%), headache (39.3%, 45.5%, 25.0%), and back pain (39.3%, 50.0%, 29.2%) were the most frequently reported all-grade adverse events (AEs) for nilotinib 300 and 400 mg BID and imatinib, respectively. Cardiovascular AEs were more common with nilotinib than with imatinib. More patients on nilotinib had pre-diabetic and diabetic levels of HbA1c (300 mg BID, 17.9% and 10.7%, respectively; 400 mg BID, 22.7% and 18.2%, respectively) compared with imatinib (4.2% each). Overall, 10-year results from the Japanese cohort are consistent with prior results from the full ENESTnd cohort and the Japanese subgroup, and continue to support the long-term use of nilotinib in Japanese patients with newly diagnosed CML-CP, but with proper monitoring and management of comorbidities.

Targeting Akt in cancer for precision therapy

Biomarkers-guided precision therapeutics has revolutionized the clinical development and administration of molecular-targeted anticancer agents. Tailored precision cancer therapy exhibits better response rate compared to unselective treatment. Protein kinases have critical roles in cell signaling, metabolism, proliferation, survival and migration. Aberrant activation of protein kinases is critical for tumor growth and progression. Hence, protein kinases are key targets for molecular targeted cancer therapy. The serine/threonine kinase Akt is frequently activated in various types of cancer. Activation of Akt promotes tumor progression and drug resistance. Since the first Akt inhibitor was reported in 2000, many Akt inhibitors have been developed and evaluated in either early or late stage of clinical trials, which take advantage of liquid biopsy and genomic or molecular profiling to realize personalized cancer therapy. Two inhibitors, capivasertib and ipatasertib, are being tested in phase III clinical trials for cancer therapy. Here, we highlight recent progress of Akt signaling pathway, review the up-to-date data from clinical studies of Akt inhibitors and discuss the potential biomarkers that may help personalized treatment of cancer with Akt inhibitors. In addition, we also discuss how Akt may confer the vulnerability of cancer cells to some kinds of anticancer agents.

Long-Term Outcome of Philadelphia Chromosome Positive Leukemia From Eastern Indian Subcontinent: An Experience in the Era of Tyrosine Kinase Inhibitor (TKI) Therapy

INTRODUCTION

Philadelphia chromosome (Ph) marks a group of leukemia with almost all cases of chronic myeloid leukemia (CML), a subset of acute lymphoid leukemia (ALL) and rare cases of acute myeloid leukemia (AML). In the era of precision medicine, such cases are successfully managed with tyrosine kinase inhibitor (TKI) drugs. This study examined the features and long-term outcome of Ph+ve cases from a tertiary cancer care center from Eastern Indian subcontinent.

MATERIALS AND METHODS

Reviewing retrospective case-records registered between 2005 and 2015, cases of CML and ALL were documented under Ph+ve category; while no instance of Ph+ve AML was found.

RESULTS

In CML cohort, adult and juvenile incidences were 95.2% and 4.8% respectively; in ALL cohort, the same was found for 66.67% and 33.33% cases. Among the CML cases, 10-year overall survival (OS) and progression-free survival (PFS) were significantly affected upon the phase of disease at time of detection. Furthermore, both OS and PFS significantly dropped whenever non-TKI-based treatment was applied prior to TKI-commencement. Long-term (10-year) sensitivity to 1st generation TKI, imatinib, was noted 88.51% and 83.33% for adult and juvenile CML cohorts, respectively. For Ph+ ALL cohort, the OS was benefitted upon combinatorial TKI and chemotherapy. However, large fractions of affected individual from CML as well as ALL cohorts were found to discontinue follow-up.

CONCLUSION

Together with differences in outcome on the basis of drug-use from onset, age (juvenile versus adult) and stage at diagnosis, our analyses bring forward the real-world scenario of Ph+ve leukemia managed with precision medicine.

Treatment-Free Remission-A New Aim in the Treatment of Chronic Myeloid Leukemia

Tyrosine kinases inhibitors (TKIs) revolutionized chronic myeloid leukemia (CML) treatment for many years, prolonging patients' life expectancy to be comparable to age-matched healthy individuals. According to the latest the European LeukemiaNet (ELN) recommendations, CML treatment aims to achieve long-term remission without treatment (TFR), which is feasible in more than 40% of patients. Nearly all molecular relapses occur during the first 6 months after TKI withdrawal and do not progress to clinical relapse. The mechanisms that are responsible for CML relapses remain unexplained. It is suggested that maintaining TFR is not directly related to the total disposing of the gene transcript BCR-ABL1, but it might be a result of the restoration of the immune surveillance in CML. The importance of the involvement of immunocompetent cells in the period of TKI withdrawal is also emphasized by the presence of specific symptoms in some patients with "withdrawal syndrome". The goal of this review is to analyze data from studies regarding TFRs in order to characterize the elements of the immune system of patients that might prevent CML molecular relapse. The role of modern droplet digital polymerase chain reaction (ddPCR) and next-generation sequencing (NGS) in better identification of low levels of BCR-ABL1 transcripts was also taken into consideration for refining the eligibility criteria to stop TKI therapy.

Philadelphia-positive B-lymphoblastic leukemia in a middle-income country - A real-world multicenter cohort

Outside of clinical trials, few studies have addressed the outcomes of Ph+ acute lymphoblastic leukemia (ALL) in adults, especially from developing world. In this study, we conducted a multicenter analysis on the outcomes of patients aged > 15 years with Ph+ ALL, aiming to get to know an overview of the Brazilian experience as well as to explore baseline factors associated with relapse and mortality in our setting. Over these 10 years, patients were treated with diverse protocols, all of them always combined with a frontline tyrosine-kinase inhibitor. A total of 123 Ph+ ALL patients was included. Imatinib was the first line TKI in 97 %. The complete response rate was 79 %. The early death rate was 15 %, being associated with increasing age at diagnosis (p = 0.06). The use of intensive versus attenuated induction regimen was not associated with higher induction mortality (p = 0.99). Overall, 29 % of patients aged ≤ 60 years underwent allogeneic transplantation, 87 % in first CR. 4-year overall survival (OS) and relapse-free survival were 25 % and 24 %, respectively. The incidence of relapse (death as a competitor) was 29 %, while the non-relapse mortality was 42 %. Only age was independently associated with OS, and lactate dehydrogenase level and central nervous disease at diagnosis were related to relapse in our cohort. This is the first historical cohort multicenter study on Ph+ ALL from Brazil. Reporting these outcomes is essential to encourage public policies to expand access to new drugs and transplantation in middle-income countries.

Targeting Leukemic Stem Cells in Chronic Myeloid Leukemia: Is It Worth the Effort?

Chronic myeloid leukemia (CML) is a classical example of stem cell cancer since it arises in a multipotent hematopoietic stem cell upon the acquisition of the t(9;22) chromosomal translocation, that converts it into a leukemic stem cell (LSC). The resulting BCR-ABL1 fusion gene encodes a deregulated tyrosine kinase that is recognized as the disease driver. Therapy with tyrosine kinase inhibitors (TKIs) eliminates progenitor and more differentiated cells but fails to eradicate quiescent LSCs. Thus, although many patients obtain excellent responses and a proportion of them can even attempt treatment discontinuation (treatment free remission [TFR]) after some years of therapy, LSCs persist, and represent a potentially dangerous reservoir feeding relapse and hampering TFR. Over the past two decades, intensive efforts have been devoted to the characterization of CML LSCs and to the dissection of the cell-intrinsic and -extrinsic mechanisms sustaining their persistence, in an attempt to find druggable targets enabling LSC eradication. Here we provide an overview and an update on these mechanisms, focusing in particular on the most recent acquisitions. Moreover, we provide a critical appraisal of the clinical relevance and feasibility of LSC targeting in CML.

Pharmacogenomics of Impaired Tyrosine Kinase Inhibitor Response: Lessons Learned From Chronic Myelogenous Leukemia

The use of small molecules became one key cornerstone of targeted anti-cancer therapy. Among them, tyrosine kinase inhibitors (TKIs) are especially important, as they were the first molecules to proof the concept of targeted anti-cancer treatment. Since 2001, TKIs can be successfully used to treat chronic myelogenous leukemia (CML). CML is a hematologic neoplasm, predominantly caused by reciprocal translocation t(9;22)(q34;q11) leading to formation of the so-called BCR-ABL1 fusion gene. By binding to the BCR-ABL1 kinase and inhibition of downstream target phosphorylation, TKIs, such as imatinib or nilotinib, can be used as single agents to treat CML patients resulting in 80 % 10-year survival rates. However, treatment failure can be observed in 20-25 % of CML patients occurring either dependent or independent from the BCR-ABL1 kinase. Here, we review approved TKIs that are indicated for the treatment of CML, their side effects and limitations. We point out mechanisms of TKI resistance focusing either on BCR-ABL1-dependent mechanisms by summarizing the clinically observed BCR-ABL1-mutations and their implications on TKI binding, as well as on BCR-ABL1-independent mechanisms of resistances. For the latter, we discuss potential mechanisms, among them cytochrome P450 implications, drug efflux transporter variants and expression, microRNA deregulation, as well as the role of alternative signaling pathways. Further, we give insights on how TKI resistance could be analyzed and what could be learned from studying TKI resistance in CML in vitro.

Treatment of Adults and Young Adults with Acute Lymphoblastic Leukemia: Real Life Data from Two Centers in Slovakia

INTRODUCTION

The results of treatment of acute lymphoblastic leukemia (ALL) from the low population countries are missing in the literature.

PATIENTS AND METHODS

We retrospectively examined biological characteristics and survival of 90 patients with ALL.

RESULTS

At median follow-up 17 months, 52 men and 38 women were eligible for the analysis with median age 43 years (18-74). As for the risk stratification, 25.6% of patients were in standard risk, 46.7% in high risk and 27.8% in very high-risk group. Complete remission achieved 88.9% of patients. We observed 5.6% of induction deaths and 4.5% of resistant disease. 47.8% of the patients underwent allogeneic stem cell transplantation (alloSCT), 59% in the young adults (YA; < 40 years) and 40% in adult group (≥ 40 years). We noticed 32.6% relapses overall with median survival of relapsed patients 3.9 months. YA patients had longer survival than adults: 3-year overall survival (OS) 65.0% vs 30.2%; (HR = 0.36; 95% CI 0.2-0.64; P = .001) and event free survival (EFS) 51.5% vs 21.9%; (HR = 0.45; 95% CI 0.26-0.78; P = .005). There was significant difference in 3-year EFS between risk groups in YA patients 90.9%, 48.0%, 11.4%; (P = .001). OS after alloSCT individually for the YA was 62.6% and for adults 39.1%, hazard ratio (HR) = 0.49 (95% CI 0.20-1.21); (P = .095). We observed 14% early deaths, 25.6% late deaths and 3 relapses (7%) after allogeneic stem cell transplantation.

CONCLUSIONS

Our data proved that even in a low population country similar result can be achieved as in larger ones while using well designed adapted protocols from leukemic study groups.

The impact of tyrosine kinase inhibitors on allogeneic hematopoietic stem cell transplantation for adult patients with Philadelphia chromosome-positive acute lymphoblastic leukemia

In the tyrosine kinase inhibitor (TKI) era, allogeneic hematopoietic stem cell transplantation (allo-HSCT) is still the most potential approach for cure of adult patients with Philadelphia chromosome-positive acute lymphocytic leukemia (Ph⁺ ALL). TKI plus chemotherapy has strikingly increased response rates and depth of response, and facilitated allo-HSCT, which decreases relapse and improves survival eventually. Meanwhile, for those with older age or comorbidities at diagnosis, TKI in combination with reduced-intensity chemotherapy or chemotherapy-free strategy reduces treatment-related mortality, deferred intensive chemotherapy increases molecular responses and reduced-intensity conditioning (RIC) allo-HSCT improves survival finally. Of note, according to minimal residual disease (MRD) and BCR/ABL1 kinase domain mutation screening, prophylactic or preemptive maintenance therapy with a sensitive TKI decreases relapse further. Regarding transplantation-related mortality and impaired quality of life related to complications of allo-HSCT, autologous-HSCT (auto-HSCT) among those with early and persistent molecular remission and the most potent TKI ponatinib plus intensive chemotherapy has exhibited non-inferior survival to allo-HSCT. Even so, risk-adapted strategy isn't available now. Lastly, outcomes of relapse after allo-HSCT are dismal due to TKIs exposure, and new therapeutic interventions combined with TKIs shed light on this thorny problem.

Crizotinib acts as ABL1 inhibitor combining ATP-binding with allosteric inhibition and is active against native BCR-ABL1 and its resistance and compound mutants BCR-ABL1T315I and BCR-ABL1T315I-E255K

Resistance remains the major clinical challenge for the therapy of Philadelphia chromosome-positive (Ph+) leukemia. With the exception of ponatinib, all approved tyrosine kinase inhibitors (TKIs) are unable to inhibit the common "gatekeeper" mutation T315I. Here we investigated the therapeutic potential of crizotinib, a TKI approved for targeting ALK and ROS1 in non-small cell lung cancer patients, which inhibited also the ABL1 kinase in cell-free systems, for the treatment of advanced and therapy-resistant Ph+ leukemia. By inhibiting the BCR-ABL1 kinase, crizotinib efficiently suppressed growth of Ph+ cells without affecting growth of Ph- cells. It was also active in Ph+ patient-derived long-term cultures (PD-LTCs) independently of the responsiveness/resistance to other TKIs. The efficacy of crizotinib was confirmed in vivo in syngeneic mouse models of BCR-ABL1- or BCR-ABL1^T315I-driven chronic myeloid leukemia-like disease and in BCR-ABL1-driven acute lymphoblastic leukemia (ALL). Although crizotinib binds to the ATP-binding site, it also allosterically affected the myristol binding pocket, the binding site of GNF2 and asciminib (former ABL001). Therefore, crizotinib has a seemingly unique double mechanism of action, on the ATP-binding site and on the myristoylation binding pocket. These findings strongly suggest the clinical evaluation of crizotinib for the treatment of advanced and therapy-resistant Ph+ leukemia.

A study of deregulated MMR pathways and anticancer potential of curcuma derivatives using computational approach

Plant derived products have steadily gained momentum in treatment of cancer over the past decades. Curcuma and its derivatives, in particular, have diverse medicinal properties including anticancer potential with proven safety as supported by numerous in vivo and in vitro studies. A defective Mis-Match Repair (MMR) is implicated in solid tumors but its role in haematologic malignancies is not keenly studied and the current literature suggests that it is limited. Nonetheless, there are multiple pathways interjecting the mismatch repair proteins in haematologic cancers that may have a direct or indirect implication in progression of the disease. Here, through computational analysis, we target proteins that are involved in rewiring of multiple signaling cascades via altered expression in cancer using various curcuma derivatives (Curcuma longa L. and Curcuma caesia Roxb.) which in turn, profoundly controls MMR protein function. These biomolecules were screened to identify their efficacy on selected targets (in blood-related cancers); aberrations of which adversely impacted mismatch repair machinery. The study revealed that of the 536 compounds screened, six of them may have the potential to regulate the expression of identified targets and thus revive the MMR function preventing genomic instability. These results reveal that there may be potential plant derived biomolecules that may have anticancer properties against the tumors driven by deregulated MMR-pathways.