Ponatinib in chronic myeloid leukemia (CML): Consensus on patient treatment and management from a European expert panel

Premature senescence and cardiovascular disease following cancer treatments: mechanistic insights

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality, especially among the aging population. The "response-to-injury" model proposed by Dr. Russell Ross in 1999 emphasizes inflammation as a critical factor in atherosclerosis development, with atherosclerotic plaques forming due to endothelial cell (EC) injury, followed by myeloid cell adhesion and invasion into the blood vessel walls. Recent evidence indicates that cancer and its treatments can lead to long-term complications, including CVD. Cellular senescence, a hallmark of aging, is implicated in CVD pathogenesis, particularly in cancer survivors. However, the precise mechanisms linking premature senescence to CVD in cancer survivors remain poorly understood. This article aims to provide mechanistic insights into this association and propose future directions to better comprehend this complex interplay.

Ponatinib: An update on its drug targets, therapeutic potential and safety

Leukemia is a malignancy of the hematopoietic system, and as its pathogenesis has become better understood, three generations of tyrosine kinase inhibitors (TKIs) have been developed. Ponatinib is the third-generation breakpoint cluster region (BCR) and Abelson (ABL) TKI, which has been influential in the leukemia therapy for a decade. Moreover, ponatinib is a potent multi-target kinase inhibitor that acts on various kinases, such as KIT, RET, and Src, making it a promising treatment option for triple-negative breast cancer (TNBC), lung cancer, myeloproliferative syndrome, and other diseases. The drug's significant cardiovascular toxicity poses a significant challenge to its clinical use, requiring the development of strategies to minimize its toxicity and side effects. In this article, the pharmacokinetics, targets, therapeutic potential, toxicity and production mechanism of ponatinib will be reviewed. Furthermore, we will discuss methods to reduce the drug's toxicity, providing new avenues for research to improve its safety in clinical use.

Dose optimisation of ponatinib in chronic phase chronic myeloid leukemia

INTRODUCTION

Ponatinib exhibits a high inhibition potency on wild-type and most mutated forms of the BCR:ABL1 kinase, but also a significant cardiovascular toxicity. Improving the efficacy/safety ratio should allow patients to safely draw benefit from the drug.

AREAS COVERED

Based on pharmacological findings and international guidelines on chronic myeloid leukemia and cardiovascular risk management, as well as on the most recent data collected in real-life studies and in a randomized phase II trial, we propose a decision-tree of dose selection of the drug.

EXPERT OPINION

We distinguish (1) highly resistant patients according to poor previous response to second generation tyrosine kinase inhibitors (complete hematologic response or less) or to mutational status (T315I, E255V, alone or within compound mutations), requiring a starting daily dose of 45 mg, reduced to 15 or 30 mg according to the patient's profile, preferentially upon major molecular achievement (3-log reduction or MR3, BCR:ABL1 ≤ 0.1%IS); (2) less-resistant patients justifying an initial dose of 30 mg, reduced to 15 mg upon MR2 (BCR:ABL1 ≤ 1%IS) or preferentially MR3 in patients with a favorable safety profile; (3) intolerant patients to be treated by 15 mg.

HDAC inhibitor chidamide overcomes drug resistance in chronic myeloid leukemia with the T315i mutation through the Akt-autophagy pathway

Currently, therapy for Chronic Myeloid Leukemia (CML) patients with the T315I mutation is a major challenge in clinical practice due to its high degree of resistance to first- and second-generation Tyrosine Kinase Inhibitors (TKIs). Chidamide, a Histone Deacetylase Inhibitor (HDACi) drug, is currently used to treat peripheral T-cell lymphoma. In this study, we investigated the anti-leukemia effects of chidamide on the CML cell lines Ba/F3 P210 and Ba/F3 T315I and primary tumor cells from CML patients with the T315I mutation. The underlying mechanism was investigated, and we found that chidamide could inhibit Ba/F3 T315I cells at G0/G1 phase. Signaling pathway analysis showed that chidamide induced H3 acetylation, downregulated pAKT expression and upregulated pSTAT5 expression in Ba/F3 T315I cells. Additionally, we found that the antitumor effect of chidamide could be exerted by regulating the crosstalk between apoptosis and autophagy. When chidamide was used in combination with imatinib or nilotinib, the antitumor effects were enhanced compared with chidamide alone in Ba/F3 T315I and Ba/F3 P210 cells. Therefore, we conclude that chidamide may overcome T315I mutation-related drug resistance in CML patients and works efficiently if used in combination with TKIs.

Potential of Withaferin-A, Withanone and Caffeic Acid Phenethyl ester as ATP-competitive inhibitors of BRAF: A bioinformatics study

Serine/threonine-protein kinase B-raf (BRAF) plays a significant role in regulating cell division and proliferation through MAPK/ERK pathway. The constitutive expression of wild-type BRAF (BRAF^WT) and its mutant forms, especially V600E (BRAF^V600E), has been linked to multiple cancers. Various synthetic drugs have been approved and are in clinical trials, but most of them are reported to become ineffective within a short duration. Therefore, combinational therapy involving multiple drugs are often recruited for cancer treatment. However, they lead to toxicity and adverse side effects. In this computational study, we have investigated three natural compounds, namely Withaferin-A (Wi-A), Withanone (Wi-N) and Caffeic Acid Phenethyl ester (CAPE) for anti-BRAF^WT and anti-BRAF^V600E activity. We found that these compounds could bind stably at ATP-binding site in both BRAF^WT and BRAF^V600E proteins. In-depth analysis revealed that these compounds maintained the active conformation of wild-type BRAF protein by inducing αC-helix-In, DFG-In, extended activation segment and well-aligned R-spine residues similar to already known drugs Vemurafenib (VEM), BGB283 and Ponatinib. In terms of binding energy, among the natural compounds, CAPE showed better affinity towards both wild-type and V600E mutant proteins than the other two compounds. These data suggested that CAPE, Wi-A and Wi-N have potential to block constitutive autophosphorylation of BRAF and hence warrant in vitro and in vivo experimental validation.

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Out of all the human cancers approximately 8% involve BRAF mutations.

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The 40–50% of the commercialized drugs in the market are from the natural sources or inspired by it.

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Three natural compounds Withaferin-A , Withanone and Caffeic acid phenethyl ester (CAPE) have been studied against BRAF.

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CAPE binds with higher binding affinity with BRAF wild type protein and BRAF V600E mutant protein than other natural compounds.

Pharmacology and pharmacovigilance of protein kinase inhibitors

Protein kinase inhibitors experienced their advent in the 2000s. Their market introduction made it possible to constitute a class of targeted therapies administered orally. This name was chosen to mark a break with conventional chemotherapy drugs, but it is important to stress that these are multi-target drugs with complex affinity profiles. Adverse effects can be explained by direct interactions with their targets of interest, chosen for their indications (on-target) but also interactions with other targets (off-target). The adverse effect profiles of these drugs are therefore varied and it is possible to identify common profiles related to inhibitions of common targets. Identification of these targets has improved the global understanding of the pathophysiological mechanisms underlying the onset of adverse drug reactions as well as of the related diseases, and makes it possible to predict the adverse effect profile of new protein kinase inhibitors based on their affinities. In this review, we describe the main adverse drug reactions associated with protein kinase inhibitors, their frequency and their plausible mechanisms of action.

Identification of potential genes associated with ALDH1A1 overexpression and cyclophosphamide resistance in chronic myelogenous leukemia using network analysis

Cyclophosphamide (CP), an important alkylating agent which is used in the treatment therapy for chronic myeloid leukemia (CML). However, acquired drug resistance owing to the inactivation of its active metabolite aldophosphamide via tumoral-overexpressing aldehyde dehydrogenase (ALDH1A1) is one of the major issues with the CP therapy. However, the underlying mechanism of ALDH1A1 overexpression in cancer cells remains poorly defined. Therefore, the current study focused on analyzing the ALDH1A1-overexpressing microarray data for CP resistance and CP-sensitive CML cell lines. In this study, the microarray dataset was obtained from Gene Expression Omnibus GEO. The GEO2R tool was used to identify Differentially Expressing Genes (DEGs). Further, protein-protein interaction (PPI) network of DEGs were constructed using STRING database. Finally, Hub gene-miRNA-TFs interaction were constructed using miRNet tool. A total of 749 DEGs including 387 upregulated and 225 downregulated genes were identified from this pool of microarray data. The construction of DEGs network resulted in identification of three genes including ZEB2, EZH2, and MUC1 were found to be majorly responsible for ALDH1A1 overexpression. miRNA analysis identified that, hsa-mir-16-5p and hsa-mir-26a-5p as hub miRNA which are commonly interacting with maximum target genes. Additionally, drug-gene interaction analysis was performed to identify drugs which are responsible for ALDH1A1 expression. The entire study may provide a deeper understanding about ALDH1A1 regulatory genes responsible for its overexpression in CP resistance cancer. This understanding may be further explore for developing possible co-therapy to avoid the ALDH1A1-mediated CP resistance.

Clinical outcomes in patients with Philadelphia chromosome-positive leukemia treated with ponatinib in routine clinical practice-data from a Belgian registry

Data on clinical use of ponatinib are limited. This prospective registry aimed to evaluate outcomes of ponatinib treatment in routine practice over 3 years (2016–2019) in Belgium (NCT03678454). Patients with chronic myeloid leukemia (CML) or Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) were treated with ponatinib per current label. Fifty patients (33 CML and 17 Ph+ ALL) were enrolled. Fifty-five percent of CML and 29% of Ph+ ALL patients had received ≥3 prior tyrosine kinase inhibitors (TKIs). Reasons for starting ponatinib were intolerance (40%), relapse or refractoriness (28%) to previous TKIs, progression (16%), or T315I mutation (16%). Median follow-up was 15 months for CML and 4.5 months for Ph+ ALL patients. Best response was a major molecular response in 58% of CML and 41% of Ph+ ALL patients. Of 20 patients who started ponatinib due to intolerance to previous TKIs, 9 (64%) CML and 4 (67%) Ph+ ALL achieved a major molecular response. Three-year estimates of overall survival were 85.3% and 85.6%, respectively, in CML and Ph+ ALL patients; estimated progression-free survival was 81.6% and 48.9%. Adverse reactions were reported in 34 patients (68%); rash (26%) and dry skin (10%) were most common. Reported cardiovascular adverse reactions included vascular stenosis (3), arterial hypertension (2), chest pain (1), palpitations (1), and vascular occlusion (1). This Belgian registry confirms results from the PACE clinical trial and supports routine ponatinib use in CML and Ph+ ALL patients who are resistant or intolerant to previous TKIs or with the T315I mutation.

Development of a cobalt(iii)-based ponatinib prodrug system

Receptor tyrosine kinase inhibitors have become a central part of modern targeted cancer therapy. However, their curative potential is distinctly limited by both rapid resistance development and severe adverse effects. Consequently, tumor-specific drug activation based on prodrug designs, exploiting tumor-specific properties such as hypoxic oxygen conditions, is a feasible strategy to widen the therapeutic window. After proof-of-principal molecular docking studies, we have synthesized two cobalt(iii) complexes using a derivative of the clinically approved Abelson (ABL) kinase and fibroblast growth factor receptor (FGFR) inhibitor ponatinib. Acetylacetone (acac) or methylacetylacetone (Meacac) have been used as ancillary ligands to modulate the reduction potential. The ponatinib derivative, characterized by an ethylenediamine moiety instead of the piperazine ring, exhibited comparable cell-free target kinase inhibition potency. Hypoxia-dependent release of the ligand from the cobalt(iii) complexes was proven by changed fluorescence properties, enhanced downstream signaling inhibition and increased in vitro anticancer activity in BCR-ABL- and FGFR-driven cancer models. Respective tumor-inhibiting in vivo effects in the BCR-ABL-driven K-562 leukemia model were restricted to the cobalt(iii) complex with the higher reduction potential and confirmed in a FGFR-driven urothelial carcinoma xenograft model. Summarizing, we here present for the first time hypoxia-activatable prodrugs of the clinically approved tyrosine kinase inhibitor ponatinib and a correlation of the in vivo activity with their reduction potential.

Chronic Myelogenous Leukemia in Childhood

PURPOSE OF REVIEW

Chronic myelogenous leukemia (CML) is rare in children, requiring extrapolation from treatment of adults. In this review, we explore similarities and differences between adult and pediatric CML with a focus on therapeutic advances and emerging clinical questions.

RECENT FINDINGS

Pediatric CML is effectively treated with long-term targeted therapy using tyrosine kinase inhibitors (TKIs). Newly diagnosed pediatric patients in chronic phase can now be treated with imatinib, dasatinib, or nilotinib without allogeneic hematopoietic stem cell transplantation. While treatment-free remission is possible in adults in chronic phase with optimal response to therapy, data are currently insufficient to support stopping TKI in pediatrics outside of a clinical trial. Knowledge gaps remain regarding long-term and late effects of TKIs in pediatric CML. Targeted therapy has markedly improved outcomes for pediatric CML, while raising a number of clinical questions, including the possibility of treatment-free remission and long-term health implications of prolonged TKI exposure at a young age.

Chronic myeloid leukemia-from the Philadelphia chromosome to specific target drugs: A literature review

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm and was the first neoplastic disease associated with a well-defined genotypic anomaly - the presence of the Philadelphia chromosome. The advances in cytogenetic and molecular assays are of great importance to the diagnosis, prognosis, treatment, and monitoring of CML. The discovery of the breakpoint cluster region (BCR)-Abelson murine leukemia (ABL) 1 fusion oncogene has revolutionized the treatment of CML patients by allowing the development of targeted drugs that inhibit the tyrosine kinase activity of the BCR-ABL oncoprotein. Tyrosine kinase inhibitors (known as TKIs) are the standard therapy for CML and greatly increase the survival rates, despite adverse effects and the odds of residual disease after discontinuation of treatment. As therapeutic alternatives, the subsequent TKIs lead to faster and deeper molecular remissions; however, with the emergence of resistance to these drugs, immunotherapy appears as an alternative, which may have a cure potential in these patients. Against this background, this article aims at providing an overview on CML clinical management and a summary on the main targeted drugs available in that context.

Discovery of a highly potent kinase inhibitor capable of overcoming multiple imatinib-resistant ABL mutants for chronic myeloid leukemia (CML)

As the critical driving force for chronic myeloid leukemia (CML), BCR gene fused ABL kinase has been extensively explored as a validated target of drug discovery. Although imatinib has achieved tremendous success as the first-line treatment for CML, the long-term application ultimately leads to resistance, primarily via various acquired mutations occurring in the BCR-ABL kinase. Although dasatinib and nilotinib have been approved as second-line therapies that could overcome some of these mutants, the most prevalent gatekeeper T315I mutant remains unconquered. Here, we report a novel type II kinase inhibitor, CHMFL-48, that potently inhibits the wild-type BCR-ABL (wt) kinase as well as a panel of imatinib-resistant mutants, including T315I, F317L, E255K, Y253F, and M351T. CHMFL-48 displayed great inhibitory activity against ABL wt (IC₅₀: 1 nM, 70-fold better than imatinib) and the ABL T315I mutant (IC₅₀: 0.8 nM, over 10,000-fold better than imatinib) in a biochemical assay and potently blocked the autophosphorylation of BCR-ABL wt and BCR-ABL mutants in a cellular context, which further affected downstream signalling mediators, including signal transducer and activator of transcription 5 (STAT5) and CRK like proto-oncogene (CRKL), and led to the cell cycle progression blockage as well as apoptosis induction. CHMFL-48 also exhibited great anti-leukemic efficacies in vivo in K562 cells and p210-T315I-transformed BaF3 cell-inoculated murine models. This discovery extended the pharmacological diversity of BCR-ABL kinase inhibitors and provided more potential options for anti-CML therapies.

Arterial Thrombotic Complications of Tyrosine Kinase Inhibitors

Abnormal expression or function of several classes of kinases contribute to the development of many types of solid and hematologic malignancies. TKs (tyrosine kinases) in particular play a role in tumor growth, metastasis, neovascularization, suppression of immune surveillance, and drug resistance. TKIs (tyrosine kinase inhibitors) targeted to TKs such as BCR-ABL1, VEGF receptors, PDGF receptors, have transformed therapy of certain forms of cancer by providing excellent efficacy with relatively low adverse event rates. Yet some of these agents have been associated with high rates of vascular events, presumably from prothrombotic complications that result in myocardial infarction, stroke, and critical limb ischemia. This review describes the scope of the problem evidenced by clinical experience with some of the most commonly used TKIs, with a focus on TKIs targeted to the BCR-ABL1 (breakpoint cluster region-Abelson 1) translocation. We also discuss the potential mechanisms responsible for arterial thrombotic complications that could lead to mitigation strategies or unique TK targeting strategies to reduce adverse event rates without compromising efficacy.

Current Treatment Options for Chronic Myeloid Leukemia Patients Failing Second-Generation Tyrosine Kinase Inhibitors

Despite the excellent overall survival (OS) of patients with chronic myeloid leukemia (CML), a significant proportion will not achieve optimal response to imatinib or second-generation tyrosine kinase inhibitors (2GTKI). For patients with inadequate response to 2GTKIs, alternative 2GTKIs or ponatinib are widely available treatment options in daily clinical practice. Treatment decisions should be guided by correct identification of the cause of treatment failure and accurate distinction between resistant from intolerant or nonadherence patients. This review aims to provide practical advice on how to select the best treatment option in each clinical scenario.

Bcr-Abl Tyrosine Kinase Inhibitors in the Treatment of Pediatric CML

The therapeutic approach to Chronic Myeloid Leukemia (CML) has changed since the advent of the tyrosine kinase inhibitor (TKI) imatinib, which was then followed by the second generation TKIs dasatinib, nilotinib, and, finally, by ponatinib, a third-generation drug. At present, these therapeutic options represent the first-line treatment for adults. Based on clinical experience, imatinb, dasatinib, and nilotinib have been approved for children even though the studies that were concerned with efficacy and safety toward pediatric patients are still awaiting more specific and high-quality data. In this scenario, it is of utmost importance to prospectively validate data extrapolated from adult studies to set a standard therapeutic management for pediatric CML by employing appropriate formulations on the basis of pediatric clinical trials, which allow a careful monitoring of TKI-induced adverse effects especially in growing children exposed to long-term therapy.

The multi-tyrosine kinase inhibitor ponatinib for chronic myeloid leukemia: Real-world data

Development of the highly selective targeted tyrosine kinase inhibitors (TKIs) has expanded the therapeutic options for chronic myeloid leukemia (CML). Patients undergoing TKI therapy should be closely monitored to ensure that the best therapeutic response and quality of life are achieved, and to control suboptimal responses and adverse events. Despite the high rate of response using current first-line TKIs, treatment failure may still occur, and resistance is considered a challenge in the treatment of patients with CML. The third-generation TKI, ponatinib, is a potent orally bioavailable pan BCR-ABL inhibitor that inhibits both wild-type and mutant BCR-ABL1 kinase, including the "gatekeeper" T315I mutation, which is resistant to all other currently available TKIs. This paper reviews the effectiveness, feasibility, and safety of ponatinib in the real-life clinical management of CML. Potential prognostic factors in identifying patients most likely to benefit from ponatinib treatment will be discussed, and case presentations illustrating situations encountered in real-life clinical practice are described. Ponatinib is effective in patients who have received prior TKIs in clinical studies as well as under real-life conditions. Nevertheless, the risk/benefit balance must be evaluated for each patient, particularly considering disease state, mutational status, treatment line, intolerance/resistance to prior TKIs, age, frailty, and specific comorbidities.

In vitro metabolites characterization of ponatinib in human liver microsomes using ultra-high performance liquid chromatography combined with Q-Exactive-Orbitrap tandem mass spectrometry

Ponatinib is an oral drug for the treatment of chronic myeloid leukemia and acute lymphoblastic leukemia, which has been reported to increase the risk of hepatotoxicity. The aim of this study was to characterize the metabolites of ponatinib in human liver microsomes as well as its reactive metabolites. Ponatinib was incubated with human liver microsomes in the presence of NADPH and trapping agents (glutathione or potassium cyanide). The metabolites were characterized by liquid chromatography in combination with Q-Exactive-Orbitrap-MS. Under the current conditions, six metabolites were detected and structurally identified on the basis of their accurate masses, fragmentation patterns, and retention times. M3 (N-demethylation) was unambiguously identified by matching its retention time and fragment ions with those of its reference standard. N-demethylation and oxygenation were proved to be the predominant metabolic pathways of ponatinib. In addition, two reactive metabolites (cyano adducts) were detected in human liver microsomes in the presence of potassium cyanide and NADPH, suggesting that ponatinib underwent CYP450-mediated metabolic activation, which could be one of the causative mechanisms for its hepatotoxicity. The current study provides new information regarding the metabolic profiles of ponatinib and would be helpful in understanding the effectiveness and toxicity of ponatinib, especially the mechanism of hepatotoxicity.

Validation of a Drosophila model of wild-type and T315I mutated BCR-ABL1 in chronic myeloid leukemia: an effective platform for treatment screening

Chronic myeloid leukemia (CML) is caused by a balanced chromosomal translocation resulting in the formation of BCR-ABL1 fusion gene encoding a constitutively active BCR-ABL1 tyrosine kinase, which activates multiple signal transduction pathways leading to malignant transformation. Standard treatment of CML is based on tyrosine kinase inhibitors (TKI); however, some mutations have proven elusive particularly the T315I mutation. Drosophila melanogaster is an established in vivo model for human diseases including cancer. The targeted expression of chimeric human/fly and full human BCR-ABL1 in Drosophila eyes has been shown to result in detrimental effects. In this study, we expressed human BCR-ABL1^p210 and the resistant BCR-ABL1^p210/T315I fusion oncogenes in Drosophila eyes. Expression of BCR-ABL1^p210/T315I resulted in a severe distortion of the ommatidial architecture of adult eyes with a more prominent rough eye phenotype compared to milder phenotypes in BCR-ABL1^p210 reflecting a stronger oncogenic potential of the mutant. We then assessed the efficacy of the currently used TKI in BCR-ABL1^p210 and BCR-ABL1^p210/T315I expressing flies. Treatment of BCR-ABL1^p210 expressing flies with potent kinase inhibitors (dasatinib and ponatinib) resulted in the rescue of ommatidial loss and the restoration of normal development. Taken together, we provide a CML tailored BCR-ABL1^p210 and BCR-ABL1^p210/T315I fly model which can be used to test new compounds with improved therapeutic indices.

Anticipate Your Next Move in Chronic Myeloid Leukaemia Patient Management

Treatment decisions in chronic myeloid leukaemia (CML) are complex and require the evaluation of many factors at each stage of therapy. Many patients will become resistant or intolerant to the first and subsequent lines of tyrosine kinase inhibitors (TKI) they receive, requiring them to switch to a different TKI. Clinicians are faced with many considerations when choosing subsequent treatments and an important issue is how best to manage failure on a second-generation TKI. During an interactive and case-based, Incyte-sponsored, satellite symposium at the 2019 European Hematology Association (EHA) congress, Dr Janssen and Prof Apperley discussed the current best practices for managing patients failing imatinib or second-generation TKI, considering whether second-generation TKI should be used sequentially and the timing of the introduction of a third-generation TKI (ponatinib). Dr Soverini and Dr de Lavallade discussed how regular BCR-ABL response monitoring and mutational analysis are integral to CML patient management. They highlighted the clinical relevance of low-level mutations and the necessity to prevent clonal expansion of these TKI-resistant mutants, and the accumulation of additional mutations, by switching to an effective TKI in a timely manner.

Monitoring Chronic Myeloid Leukemia: How Molecular Tools May Drive Therapeutic Approaches

More than 15 years ago, imatinib entered into the clinical practice as a "magic bullet"; from that point on, the prognosis of patients affected by chronic myeloid leukemia (CML) became comparable to that of aged-matched healthy subjects. The aims of treatment with tyrosine kinase inhibitors (TKIs) are for complete hematological response after 3 months of treatment, complete cytogenetic response after 6 months, and a reduction of the molecular disease of at least 3 logs after 12 months. Patients who do not reach their goal can switch to another TKI. Thus, the molecular monitoring of response is the main consideration of management of CML patients. Moreover, cases in deep and persistent molecular response can tempt the physician to interrupt treatment, and this "dream" is possible due to the quantitative PCR. After great international effort, today the BCR-ABL1 expression obtained in each laboratory is standardized and expressed as "international scale." This aim has been reached after the establishment of the EUTOS program (in Europe) and the LabNet network (in Italy), the platforms where biologists meet clinicians. In the field of quantitative PCR, the digital PCR is now a new and promising, sensitive and accurate tool. Some authors reported that digital PCR is able to better classify patients in precise "molecular classes," which could lead to a better identification of those cases that will benefit from the interruption of therapy. In addition, digital PCR can be used to identify a point mutation in the ABL1 domain, mutations that are often responsible for the TKI resistance. In the field of resistance, a prominent role is played by the NGS that enables identification of any mutation in ABL1 domain, even at sub-clonal levels. This manuscript reviews how the molecular tools can lead the management of CML patients, focusing on the more recent technical advances.

Comparative efficacy and tolerability of front-line treatments for newly diagnosed chronic-phase chronic myeloid leukemia: an update network meta-analysis

Background

Recent years have witnessed the rapid evolution of therapies in chronic-phase chronic myeloid leukemia (CP-CML). To assess the efficacy and tolerability of all reported front-line treatments for patients with newly diagnosed CML, a multiple-treatments meta-analysis was performed, which accounted for both direct and indirect comparisons among those treatments.

Methods

Primary outcomes were the percentage of patients achieving major molecular response (MMR) and complete cytogenetic response (CCyR) within 12 months. Secondary outcomes included the percentage of progression to accelerated phase (AP), serious adverse effects (AEs), overall discontinuation and discontinuation for drug-related AEs. Direct pairwise meta-analysis and indirect multi-comparison meta-analysis among those treatments in each outcome were both conducted. The surface under the cumulative ranking curve (SUCRA) was calculated for all treatments in each outcome. Cluster analysis demonstrated the division of treatments into distinct groupings according to efficacy and tolerability profiles.

Results

A total of 21 randomized controlled trials (RCTs, including 10,187 patients) comparing 15 different interventions for CP-CML patients were included in this study. SUCRA analysis suggested that all tyrosine kinase inhibitors (TKIs) are highly effective in newly diagnosed CP-CML when compared to traditional drugs. Newer TKIs and higher-dose imatinib generally resulted in faster cytogenetic and molecular responses when compared with standard-dose imatinib and traditional drugs. Furthermore, traditional drugs, higher-dose imatinib and newer TKIs demonstrated lower acceptability than standard-dose imatinib. One cluster of interventions, which included nilotinib (300/400 mg BID), dasatinib (100 mg QD) and radotinib (300 mg BID), demonstrated higher efficacy and tolerability than other treatments.

Conclusions

Nilotinib (300/400 mg BID), dasatinib (100 mg QD) and radotinib (300 mg BID) prove to be the most recommended front-line treatments of the greatest efficacy and tolerability for CP-CML patients. High-dose therapies are recommended only for patients in accelerated phase/blast phase or with suboptimal CML-CP response, and management of adverse events should be carried out to avoid compromising the clinical efficacy.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-6039-9) contains supplementary material, which is available to authorized users.

Thrombotic microangiopathy as a cause of cardiovascular toxicity from the BCR-ABL1 tyrosine kinase inhibitor ponatinib

The third-generation tyrosine kinase inhibitor (TKI) ponatinib has been associated with high rates of acute ischemic events. The pathophysiology responsible for these events is unknown. We hypothesized that ponatinib produces an endothelial angiopathy involving excessive endothelial-associated von Willebrand factor (VWF) and secondary platelet adhesion. In wild-type mice and ApoE-/- mice on a Western diet, ultrasound molecular imaging of the thoracic aorta for VWF A1-domain and glycoprotein-Ibα was performed to quantify endothelial-associated VWF and platelet adhesion. After treatment of wild-type mice for 7 days, aortic molecular signal for endothelial-associated VWF and platelet adhesion were five- to sixfold higher in ponatinib vs sham therapy (P < .001), whereas dasatinib had no effect. In ApoE-/- mice, aortic VWF and platelet signals were two- to fourfold higher for ponatinib-treated compared with sham-treated mice (P < .05) and were significantly higher than in treated wild-type mice (P < .05). Platelet and VWF signals in ponatinib-treated mice were significantly reduced by N-acetylcysteine and completely eliminated by recombinant ADAMTS13. Ponatinib produced segmental left ventricular wall motion abnormalities in 33% of wild-type and 45% of ApoE-/- mice and corresponding patchy perfusion defects, yet coronary arteries were normal on angiography. Instead, a global microvascular angiopathy was detected by immunohistochemistry and by intravital microscopy observation of platelet aggregates and nets associated with endothelial cells and leukocytes. Our findings reveal a new form of vascular toxicity for the TKI ponatinib that involves VWF-mediated platelet adhesion and a secondary microvascular angiopathy that produces ischemic wall motion abnormalities. These processes can be mitigated by interventions known to reduce VWF multimer size.

[Clinical characteristics of chronic myeloid leukemia with T315I mutation and the efficacy of ponatinib]

OBJECTIVE

To analyze the clinical features of chronic myeloid leukemia (CML) with T315 I mutation (CML-T315I) and compare the effectiveness of different treatments.

METHODS

We retrospectively analyzed the clinical data and outcomes of 19 patients with CML-T315I receiving different treatments. The T315 I mutations in these patients were detected by examination of BCR-ABL kinase domain (KD) mutation by RTQ-PCR and Sanger sequencing. The relapse following the treatments, defined as hematological, cytogenetic and molecular biological recurrences, were analyzed in these patients.

RESULTS

Of the 19 patients with CML-T315I, 14 (73.7%) were in CML-CP stage at the initial diagnosis, and 13 (81.2%) were high-risk patients based on the Sokal scores. All the 19 patients were treated with TKI after the initial diagnosis, and during the treatment, 15 (78.9%) patients were found to have additional chromosomal aberrations, and 10 (52.6%) had multiple mutations; 13 (68.4%) of the patients experienced disease progression (accelerated phase/blast crisis) before the detection of T315I mutation, with a median time of 40 months (5-120 months) from the initial diagnosis to the mutation detection. After detection of the mutation, 12 patients were treated with ponatinib and 7 were managed with the conventional chemotherapy regimen, and their overall survival rates at 3 years were 83.3% and 14.2%, respectively (P < 0.001).

CONCLUSIONS

CML patients resistant to TKI are more likely to have T315I mutations, whose detection rate is significantly higher in the progressive phase than in the chronic phase. These patients often have additional chromosomal aberrations and multiple gene mutations with poor prognoses and a high recurrence rate even after hematopoietic stem cell transplantation. Long-term maintenance therapy with ponatinib may improve the prognosis and prolong the survival time of the patients.

Targeting mTOR in Acute Lymphoblastic Leukemia

Acute Lymphoblastic Leukemia (ALL) is an aggressive hematologic disorder and constitutes approximately 25% of cancer diagnoses among children and teenagers. Pediatric patients have a favourable prognosis, with 5-years overall survival rates near 90%, while adult ALL still correlates with poorer survival. However, during the past few decades, the therapeutic outcome of adult ALL was significantly ameliorated, mainly due to intensive pediatric-based protocols of chemotherapy. Mammalian (or mechanistic) target of rapamycin (mTOR) is a conserved serine/threonine kinase belonging to the phosphatidylinositol 3-kinase (PI3K)-related kinase family (PIKK) and resides in two distinct signalling complexes named mTORC1, involved in mRNA translation and protein synthesis and mTORC2 that controls cell survival and migration. Moreover, both complexes are remarkably involved in metabolism regulation. Growing evidence reports that mTOR dysregulation is related to metastatic potential, cell proliferation and angiogenesis and given that PI3K/Akt/mTOR network activation is often associated with poor prognosis and chemoresistance in ALL, there is a constant need to discover novel inhibitors for ALL treatment. Here, the current knowledge of mTOR signalling and the development of anti-mTOR compounds are documented, reporting the most relevant results from both preclinical and clinical studies in ALL that have contributed significantly into their efficacy or failure.

Molecular mechanisms underlying cardiotoxicity of novel cancer therapeutics

Novel cancer therapeutics contribute to a steadily declining cancer mortality. However, several of these new therapies target pathways also involved in the cardiovascular system thus causing cardiotoxic side effects such as chemotherapy-induced heart failure (CIHF). This might limit the applicability of these effective treatments in a relevant number of patients. Furthermore, given the improving cancer survival rates, chemotherapy-induced cardiotoxic complications receive increasing attention given their potential impact on long-term morbidity and mortality. The understanding of molecular mechanisms that underlie CIHF is crucial for future improvement of pharmacodynamics of these therapeutics but also for developing specific interventions to prevent CIHF. Here, we discuss molecular mechanisms underlying CIHF of novel cancer therapeutics including a short synopsis on clinical management of patients suffering from CIHF.

Recent Studies on Ponatinib in Cancers Other Than Chronic Myeloid Leukemia

Ponatinib is a third line drug for the treatment of chronic myeloid leukemia patients, especially those that develop the gatekeeper mutation T315I, which is resistant to the first and the second line drugs imatinib, nilotinib, dasatinib and bosutinib. The compound was first identified as a pan Bcr-Abl and Src kinase inhibitor. Further studies have indicated that it is a multitargeted inhibitor that is active on FGFRs, RET, AKT, ERK1/2, KIT, MEKK2 and other kinases. For this reason, the compound has been evaluated on several cancers in which these kinases play important roles, including thyroid, breast, ovary and lung cancer, neuroblastoma, rhabdoid tumours and in myeloproliferative disorders. Ponatinib is also being tested in clinical trials to evaluate its activity in FLT3-ITD acute myelogenous leukemia, head and neck cancers, certain type of lung cancer, gastrointestinal stromal tumours and other malignancies. In this review we report the most recent preclinical and clinical studies on ponatinib in cancers other than CML, with the aim of giving a complete overview of this interesting compound.

Molecular biology as a tool for the treatment of cancer

Cancer is a genetic disease characterized by uncontrolled cell growth and metastasis. Cancer can have a number of causes, such the activation of oncogenes, the inactivation of tumor-suppressing genes, mutagenesis provoked by external factors, and epigenetic modifications. The development of diagnostic tools and treatments using a molecular biological approach permits the use of sensitive, low-cost, noninvasive tests for cancer patients. Biomarkers can be used to provide rapid, personalized oncology, in particular the molecular diagnosis of chronic myeloid leukemia, and gastric, colon, and breast cancers. Molecular tests based on DNA methylation can also be used to direct treatments or evaluate the toxic effects of chemotherapy. The adequate diagnosis, prognosis, and prediction of the response of cancer patients to treatment are essential to ensure the most effective therapy, reduce the damaging effects of treatment, and direct the therapy to specific targets, and in this context, molecular biology has become increasingly important in oncology. In this brief review, we will demonstrate the fundamental importance of molecular biology for the treatment of three types of cancer-chronic myeloid leukemia, hereditary diffuse gastric cancer, and astrocytomas (sporadic tumors of the central nervous system). In each of these three models, distinct biological mechanisms are involved in the transformation of the cells, but in all cases, molecular biology is fundamental to the development of personalized analyses for each patient and each type of neoplasia, and to guarantee the success of the treatment.

Improving Outcomes in Chronic Myeloid Leukemia Over Time in the Era of Tyrosine Kinase Inhibitors

Most patients with chronic myeloid leukemia (CML) receiving treatment with BCR-ABL1 tyrosine kinase inhibitors (TKIs) will achieve favorable responses. Moreover, TKI therapy enables patients to experience long-term survival, with survival rates similar to those of individuals without CML. This enhanced survival has resulted from the availability of multiple BCR-ABL1 TKIs with efficacy, not only in frontline treatment, but, importantly, also in second- and third-line treatment. We have reviewed the changes in long-term outcomes in the era of TKI therapy and how these changes have affected treatment practices. We discuss the development of imatinib, the first BCR-ABL1 TKI, followed by newer TKIs, including nilotinib, dasatinib, bosutinib, and ponatinib. We consider the key studies that led to their development as frontline or later-line therapies, their safety profiles, and their effect on improving patient outcomes. With these improved outcomes, the definition of an optimal response has become more stringent, and treatment monitoring strategies have changed. Second-line patient populations have evolved from those with resistance to, or intolerance of, imatinib to those with moderate responses to, or low-grade adverse events with, imatinib. Although all TKIs are associated with high survival rates, newer TKIs have been associated with lower disease progression rates and, importantly, deeper treatment responses and, potentially, a greater chance of future treatment-free remission. Finally, we consider the unmet needs of patients with CML, including the challenges remaining for those without optimal responses during TKI therapy and new therapies and strategies to identify such patients at diagnosis.

Ponatinib as second-line treatment in chronic phase chronic myeloid leukemia patients in real-life practice

Scarce information is available on the use of ponatinib as second-line treatment in chronic phase chronic myeloid leukemia (CP-CML) patients resistant and/or intolerant to prior tyrosine kinase inhibitor (TKI) therapy. We collected data from 29 CML patients, with a median age of 54 years (range 32-72). Eleven patients had received dasatinib, 15 patients received nilotinib, and 3 patients received imatinib as first-line treatment. Forty-five percent of patients started ponatinib for secondary resistance, 38% for primary resistance, 7% for severe intolerance associated to a molecular warning, 7% due to the presence of a T315I mutation, and 3% for severe intolerance. Ponatinib was started at a dose of 45 mg in 60% of patients, 30 mg in 38%, and 15 mg in 2% of patients. Overall, at a median follow-up of 12 months, 85% of treated patients improved the level of response as compared to baseline, with 10 patients achieving a deep molecular response (MR4-4.5). No thrombotic events were recorded. The dose was reduced during treatment in 2 patients due to intolerance and in 8 patients in order to reduce the cardiovascular risk. Ponatinib seems a valid second-line treatment option for chronic phase CML, in particular for patients who failed a front-line second-generation TKI due to BCR-ABL-independent mechanisms of resistance.

Novel tyrosine-kinase inhibitors for the treatment of chronic myeloid leukemia: safety and efficacy

INTRODUCTION

Chronic myeloid leukemia (CML) is characterized by a pathognomonic chromosomal translocation, which leads to the fusion of breakpoint cluster region (BCR) and Abelson leukemia virus 1 (ABL1) genes, generating an oncoprotein with deregulated tyrosine kinase activity. Areas covered: In the last two decades, BCR/ABL1 kinase has become the molecular target for tyrosine kinase inhibitors (TKIs), a class of drugs that impressively improved overall survival. Despite these results, a proportion of patients experiences resistance to TKIs and need to change treatment. Furthermore, TKIs are unable to eradicate leukemic stem cells, allowing the persistence of neoplastic clones. Therefore, there is still clinical need for new agents to overcome common resistance mechanisms to available drugs. This review explores the horizon of drugs actually under investigation for CML patients resistant to conventional treatment. Expert commentary: Radotinib is an ATP-competitive TKI that showed significant activity also in front-line setting and could find employment indications in CML. Asciminib, an allosteric ABL1 inhibitor, could demonstrate a higher capacity in overcoming common TKIs resistant mutations, including T315I, but clinical findings are needed. CML stem cell target will probably require new therapeutic strategies: combinations of several compounds acting with different mechanisms of action are actually under investigation.