Class effects of tyrosine kinase inhibitors in the treatment of chronic myeloid leukemia

Non-Receptor Tyrosine Kinases: Their Structure and Mechanistic Role in Tumor Progression and Resistance

Protein tyrosine kinases (PTKs) function as key molecules in the signaling pathways in addition to their impact as a therapeutic target for the treatment of many human diseases, including cancer. PTKs are characterized by their ability to phosphorylate serine, threonine, or tyrosine residues and can thereby rapidly and reversibly alter the function of their protein substrates in the form of significant changes in protein confirmation and affinity for their interaction with protein partners to drive cellular functions under normal and pathological conditions. PTKs are classified into two groups: one of which represents tyrosine kinases, while the other one includes the members of the serine/threonine kinases. The group of tyrosine kinases is subdivided into subgroups: one of them includes the member of receptor tyrosine kinases (RTKs), while the other subgroup includes the member of non-receptor tyrosine kinases (NRTKs). Both these kinase groups function as an "on" or "off" switch in many cellular functions. NRTKs are enzymes which are overexpressed and activated in many cancer types and regulate variable cellular functions in response to extracellular signaling-dependent mechanisms. NRTK-mediated different cellular functions are regulated by kinase-dependent and kinase-independent mechanisms either in the cytoplasm or in the nucleus. Thus, targeting NRTKs is of great interest to improve the treatment strategy of different tumor types. This review deals with the structure and mechanistic role of NRTKs in tumor progression and resistance and their importance as therapeutic targets in tumor therapy.

Artificial intelligence in fusion protein three-dimensional structure prediction: Review and perspective

Recent advancements in artificial intelligence (AI) have accelerated the prediction of unknown protein structures. However, accurately predicting the three-dimensional (3D) structures of fusion proteins remains a difficult task because the current AI-based protein structure predictions are focused on the WT proteins rather than on the newly fused proteins in nature. Following the central dogma of biology, fusion proteins are translated from fusion transcripts, which are made by transcribing the fusion genes between two different loci through the chromosomal rearrangements in cancer. Accurately predicting the 3D structures of fusion proteins is important for understanding the functional roles and mechanisms of action of new chimeric proteins. However, predicting their 3D structure using a template-based model is challenging because known template structures are often unavailable in databases. Deep learning (DL) models that utilize multi-level protein information have revolutionized the prediction of protein 3D structures. In this review paper, we highlighted the latest advancements and ongoing challenges in predicting the 3D structure of fusion proteins using DL models. We aim to explore both the advantages and challenges of employing AlphaFold2, RoseTTAFold, tr-Rosetta and D-I-TASSER for modelling the 3D structures. HIGHLIGHTS: This review provides the overall pipeline and landscape of the prediction of the 3D structure of fusion protein. This review provides the factors that should be considered in predicting the 3D structures of fusion proteins using AI approaches in each step. This review highlights the latest advancements and ongoing challenges in predicting the 3D structure of fusion proteins using deep learning models. This review explores the advantages and challenges of employing AlphaFold2, RoseTTAFold, tr-Rosetta, and D-I-TASSER to model 3D structures.

Glycaemic abnormalities induced by small molecule tryosine kinase inhibitors: a review

In light of the expected increase in the prevalence of diabetes mellitus due to an aging population, sedentary lifestyles, an increase in obesity, and unhealthy diets, there is a need to identify potential pharmacological agents that can heighten the risk of developing diabetes. Similarly, it is equally important to also identify those agents that show blood glucose-lowering properties. Amongst these agents are tyrosine kinase inhibitors used to treat certain types of cancers. Over the last two decades, there has been an increase in the use of targeted chemotherapy for cancers such as renal cell carcinoma, chronic leukaemia, and gastrointestinal stromal tumours. Small molecule tyrosine kinase inhibitors have been at the forefront of targeted chemotherapy. Studies have shown that small molecule tyrosine kinase inhibitors can alter glycaemic control and glucose metabolism, with some demonstrating hypoglycaemic activities whilst others showing hyperglycaemic properties. The mechanism by which small molecule tyrosine kinase inhibitors cause glycaemic dysregulation is not well understood, therefore, the clinical significance of these chemotherapeutic agents on glucose handling is also poorly documented. In this review, the effort is directed at mapping mechanistic insights into the effect of various small molecule tyrosine kinase inhibitors on glycaemic dysregulation envisaged to provide a deeper understanding of these chemotherapeutic agents on glucose metabolism. Small molecule tyrosine kinase inhibitors may elicit these observed glycaemic effects through preservation of β-cell function, improving insulin sensitivity and insulin secretion. These compounds bind to a spectrum of receptors and proteins implicated in glucose regulation for example, non-receptor tyrosine kinase SRC and ABL. Then receptor tyrosine kinase EGFR, PDGFR, and FGFR.

Keratosis Pilaris-like Eruption during Treatment of Chronic Myeloid Leukemia with Tyrosine Kinase Inhibitors: Literature Review and Report of a Case Related to Imatinib

The advent of tyrosine kinase inhibitors (TKIs) blocking BCR-ABL activity has revolutionized the therapeutic management of patients with chronic myeloid leukemia (CML). Adverse cutaneous reactions (ACRs) are common nonhematologic adverse events associated with the use of BCR-ABL TKIs. A characteristic pattern of eruption resembling keratosis pilaris (KP) has been described in patients treated with these drugs, especially nilotinib and dasatinib. The pathogenesis of this ACR is still unknown. This type of reaction appears to be uncommon with imatinib. Here, we report the case of an elderly patient with an asymptomatic KP-like eruption, which appeared one month after starting treatment with imatinib for CML. The case presentation is accompanied by a review of similar reactions in patients with CML treated with BCR-ABL inhibitors, attempting to make an excursus on the molecular targets of such drugs and possible mechanisms underlying this ACR.

Imatinib-Induced Pleuro-Pericardial Effusion and Atrial Fibrillation: An Unusual Side Effect Following the Treatment of a Rare Gastrointestinal Tumor

Gastrointestinal stromal tumors (GISTs) are one of the most prevalent non-epithelial tumors of the GI mesenchyme. While stromal tumors account for less than 1% of all malignancies, a knowledge of their etiology and signaling pathways can aid in identifying new molecular targets for the potential development of therapeutics. One of the drugs that have shown remarkable action against GIST is imatinib, a tyrosine kinase inhibitor (TKI). We present a case of a female patient with a long-term history of heart failure (HF) with preserved ejection fraction (EF) and minimal pericardial effusion who had recently started imatinib therapy and was hospitalized after new-onset atrial fibrillation (AF) and the development of significantly increased pericardial and pleural effusion. She had been diagnosed with GIST a year ago and started on imatinib. She presented to the ER with complaints of left-sided chest pain. ECG revealed a new AF. The patient was started on rate control and anticoagulation. After a few days, she returned to the ER with complaints of shortness of breath (SOB). The patient was found to have pericardial and pleural effusions on imaging. Fluids from both effusions were aspirated and sent to pathology to rule out malignancy. The patient developed recurrent bilateral pleural effusions after discharge, which were later drained on subsequent hospitalization. Although imatinib is generally well tolerated, it does cause both AF and pleural/pericardial effusions in rare cases. In such cases, it is essential to perform a thorough workup to rule out other possibilities such as metastasis, malignancy, or infection.

Cognition in patients treated with targeted therapy for chronic myeloid leukemia: a controlled comparison

This controlled comparison study evaluated objective and subjective cognitive function and their relationships with patient-reported symptoms (depression, fatigue, insomnia) in patients receiving tyrosine kinase inhibitors (TKIs) for chronic myeloid leukemia (CML) and non-cancer controls. Patients with CML in chronic phase treated with the same oral TKI for ≥6 months (n = 90) and non-cancer controls (n = 87) completed a neurocognitive battery and self-report measures. Patients demonstrated worse overall neuropsychological performance (p = .05) and verbal memory (p = .02) compared to controls. Patients were not more likely to meet criteria for impaired cognitive performance compared to controls (ps>.26). Patients reported worse subjective global and domain-specific cognitive complaints and less satisfaction with cognitive function compared to controls (ps < .05). Patients also reported greater fatigue and insomnia symptoms (ps < .001). In both groups, greater fatigue, insomnia, and depressive symptoms were associated with worse subjective cognition (ps < .01). Longitudinal studies are needed to examine changes in cognitive function in patients before and during TKI treatment.

Impact of Tyrosine Kinase Inhibitors Applied for First-Line Chronic Myeloid Leukemia Treatment on Platelet Function in Whole Blood of Healthy Volunteers In Vitro

The tyrosine kinase inhibitors (TKIs) imatinib, dasatinib, bosutinib, and nilotinib are established for first-line treatment of chronic myeloid leukemia (CML) but may cause side effects such as bleeding and thrombotic complications. We investigated the impact of TKIs on platelet function ex vivo in anticoagulated whole blood (WB) samples from healthy adults by lumiaggregometry and PFA-100 test. Samples (n = 15 per TKI) were incubated for 30 minutes with TKI at therapeutically relevant final concentrations. Aggregation and ATP release were induced by collagen (1 µg/mL), arachidonic acid (0.5 mmol/L), and thrombin (0.5 U/mL). Imatinib, bosutinib, and nilotinib significantly increased collagen-induced aggregation compared with controls. In addition, for bosutinib and nilotinib, a significant increase in aggregation after induction with arachidonic acid was detected. ATP-release and PFA-100 closure times were not influenced significantly by these three TKI. In contrast, dasatinib demonstrated a concentration-dependent inhibition of collagen-induced aggregation and ATP release and a significant prolongation of the PFA-100 closure time with the collagen/epinephrine cartridge. Aggregation and ATP release by other agonists as well as closure time with the collagen/ADP cartridge were not influenced significantly. In conclusion, we clearly show a concentration-dependent inhibition of collagen-induced platelet function in WB by dasatinib confirming prior results obtained in platelet-rich plasma. Bosutinib and nilotinib exerted no impairment of platelet activation. On the contrary, both TKI showed signs of platelet activation. When comparing our results with existing data, imatinib in therapeutic relevant concentrations does not impair platelet function.

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.

Designing of kinase hinge binders: A medicinal chemistry perspective

Protein kinases are key regulators of cellular signaling and play a critical role in oncogenesis. Inhibitors of protein kinases are pursued by both industry and academia as a promising target for cancer therapy. Within the protein kinases, the ATP site has produced more than 40 FDA-approved drugs. The ATP site is broadly composed of a hinge region, gatekeeper residues, DFG-loop, ribose pocket, and other hydrophobic regions. The hinge region in the ATP site can be used for designing potent inhibitors. In this review, we discuss some representative studies that will highlight the interactions of heterocyclic compounds with hinge regions of different kinases like BRAF kinase, EGRF kinase, MAP kinase, and Mps1 kinase.

Molecular targeted therapy for anticancer treatment

Since the initial clinical approval in the late 1990s and remarkable anticancer effects for certain types of cancer, molecular targeted therapy utilizing small molecule agents or therapeutic monoclonal antibodies acting as signal transduction inhibitors has served as a fundamental backbone in precision medicine for cancer treatment. These approaches are now used clinically as first-line therapy for various types of human cancers. Compared to conventional chemotherapy, targeted therapeutic agents have efficient anticancer effects with fewer side effects. However, the emergence of drug resistance is a major drawback of molecular targeted therapy, and several strategies have been attempted to improve therapeutic efficacy by overcoming such resistance. Herein, we summarize current knowledge regarding several targeted therapeutic agents, including classification, a brief biology of target kinases, mechanisms of action, examples of clinically used targeted therapy, and perspectives for future development.

An evaluation of ponatinib as a therapy in adult patients with resistant/intolerant chronic-phase chronic myeloid leukemia

INTRODUCTION

Chronic myeloid leukemia is now a highly treatable leukemia due to the availability of multiple tyrosine kinase inhibitors (TKIs) inhibiting the BCR-ABL1 oncogene. Some patients with CML can display resistance or intolerance to multiple TKIs, oftentimes due to the presence of mutations in BCR-ABL1, such as T315I, which limits effective treatment options. Ponatinib is a third-generation, rationally-designed TKI with clinically meaningful activity in this difficult-to-treat population. Ponatinib is associated with an increased risk of arterial occlusive events (AOEs) which has required a re-examination of its dosing in order to limit the risk of these events.

AREAS COVERED

This review will provide an overview of the mechanism of action of ponatinib and the safety and efficacy data from clinical trials in chronic myeloid leukemia.

EXPERT OPINION

Ponatinib is a potent pan-BCR-ABL1 TKI with substantial activity in patients with more resistant or advanced CML. Its efficacy needs to be balanced with the increased risk of vascular events, which seems to be at least partially diminished by the implementation of mitigation strategies aimed at modifying cardiovascular risk factors and adaptive dosing of the drug.

Concurrence of imatinib-induced massive pleural/pericardial effusion and Campylobacter bacteremia in an adolescent with chronic myeloid leukemia

Imatinib is a crucial therapeutic strategy against chronic myeloid leukemia. Though superficial edema is a common adverse effect of imatinib, massive fluid retention is rarely reported. Here, we report the case of an adolescent who had tolerated imatinib for a long time, and then presented with massive pleural/pericardial effusion during an episode of Campylobacter jejuni bacteremia. A stepwise and comprehensive survey excluded all other plausible causes of disease. The Naranjo scale was used to assess the probability of an adverse effect of medication, and the score turned out to be 9, indicating severe fluid retention to be a definite reaction to imatinib. Drug discontinuation, antibiotic administration, and invasive procedures improved this condition. After this episode, the patient could tolerate imatinib again, illustrating the transient and reversible nature of this reaction. Since prolonged imatinib usage is crucial for chronic myeloid leukemia control, alertness to drug-related adverse effects is recommended, even if the subject has previously shown a good tolerance to the drug due to various physical conditions, especially physiological stressors, like infection or inflammation.

Small Molecule Kinase Inhibitor Drugs (1995-2021): Medical Indication, Pharmacology, and Synthesis

The central role of dysregulated kinase activity in the etiology of progressive disorders, including cancer, has fostered incremental efforts on drug discovery programs over the past 40 years. As a result, kinase inhibitors are today one of the most important classes of drugs. The FDA approved 73 small molecule kinase inhibitor drugs until September 2021, and additional inhibitors were approved by other regulatory agencies during that time. To complement the published literature on clinical kinase inhibitors, we have prepared a review that recaps this large data set into an accessible format for the medicinal chemistry community. Along with the therapeutic and pharmacological properties of each kinase inhibitor approved across the world until 2020, we provide the synthesis routes originally used during the discovery phase, many of which were only available in patent applications. In the last section, we also provide an update on kinase inhibitor drugs approved in 2021.

Target spectrum of the BCR-ABL tyrosine kinase inhibitors in chronic myeloid leukemia

BCR-ABL1 plays a key role in the pathogenesis of chronic myeloid leukemia (CML), and it has been investigated as a druggable target of tyrosine kinase inhibitors (TKIs) over two decades. Since imatinib, the first TKI for anti-cancer therapy, was successfully applied in CML therapy, further generation TKIs and a novel allosteric inhibitor targeting the myristate binding site have been developed as alternative options for CML management. However, significant concerns regarding toxicity profiles, especially in long-term treatment, have emerged from TKI clinical data. Efforts to reduce adverse events and serious complications are warranted not only for survival, but also quality of life in CML patients. A better understanding of the mechanism of action will help to identify on- and off-target effects of TKIs, and guide personalized TKI drug selection in each individual CML patient. Herein, this review summarizes the biologic mechanism of BCR-ABL1 inhibition and differential target spectra, and related off-target effects of each TKI.

Adverse events associated with nilotinib in chronic myeloid leukemia: mechanisms and management strategies

Introduction: Nilotinib is a second-generation tyrosine kinase inhibitor (TKI) targeting BCR/ABL, which is used for the first-line treatment of newly diagnosed chronic myeloid leukemia (CML) patients and the second-line treatment of most CML patients who are resistant or intolerant to prior therapy that includes imatinib. In addition to common adverse reactions, long-term use of nilotinib shows some toxicities that are different from those of occurring during other BCR/ABL TKI treatments, such as cardiovascular toxicity. It is life-threatening, which would affect not only the choice of initial treatment of CML patients but also the safety of long-term medication.Areas covered: Through searching literature and reports from PubMed and clinical trials, here we review a profile of the adverse effects induced by nilotinib. We also discuss the potential molecular toxicological mechanisms and clinical management, which may provide strategies to prevent or intervene the toxicity associated with nilotinib.Expert opinion: Severe adverse effects associated with nilotinib limit its long-term clinical application. However, the exact mechanisms underlying these toxicities remain unclear. Future research should focus on the developing strategies to reduce the toxicities of nilotinib as well as to avoid similar toxicity in the development of new drugs.

Drug-induced peripheral oedema: An aetiology-based review

Many drugs are responsible, through different mechanisms, for peripheral oedema. Severity is highly variable, ranging from slight oedema of the lower limbs to anasarca pictures as in the capillary leak syndrome. Although most often noninflammatory and bilateral, some drugs are associated with peripheral oedema that is readily erythematous (eg, pemetrexed) or unilateral (eg, sirolimus). Thus, drug-induced peripheral oedema is underrecognized and misdiagnosed, frequently leading to a prescribing cascade. Four main mechanisms are involved, namely precapillary arteriolar vasodilation (vasodilatory oedema), sodium/water retention (renal oedema), lymphatic insufficiency (lymphedema) and increased capillary permeability (permeability oedema). The underlying mechanism has significant impact on treatment efficacy. The purpose of this review is to provide a comprehensive analysis of the main causative drugs by illustrating each pathophysiological mechanism and their management through an example of a drug.

Diuretic-Resistant Ascites Following Laparoscopic Surgery in a Patient With Chronic Myeloid Leukemia on Imatinib Therapy

Imatinib mesylate is a tyrosine kinase inhibitor with high efficacy in the treatment of chronic myeloid leukemia (CML). Although fluid retention is a common adverse effect of imatinib, it rarely necessitates discontinuation of therapy. Isolated ascites has not been reported as a complication of imatinib therapy in patients with CML. Here, we report the case of a 72-year-old male with CML on imatinib (600 mg daily), who developed ascites two weeks after a laparoscopic hernia repair with intraperitoneal placement of a nylon mesh. The ascites was resistant to diuretic therapy and required repeated large-volume paracentesis. Discontinuation of imatinib resulted in arrest of ascites production, but reintroduction of the drug at the same dose two weeks later was rapidly followed by recurrence of ascites requiring further therapeutic paracenteses. It was postulated that peritoneal inflammation had resulted in increased capillary permeability, which was further augmented by imatinib via inhibition of platelet-derived growth factor receptor (PDGFR), a tyrosine kinase known to play a significant physiological role in the regulation of interstitial fluid pressure and capillary permeability. The possibility of developing ascites after abdominal surgery should be considered in patients receiving imatinib or related PDGFR inhibitors. In such cases, perioperative interruption of tyrosine kinase therapy might be indicated.

Differential gene expression analysis of dasatinib-induced colitis in a patient with chronic myeloid leukemia followed for 3 years: a case report

BACKGROUND

Dasatinib is a second-generation tyrosine kinase inhibitor (TKI) developed for treatment of patients with chronic myeloid leukemia (CML). The drug has been shown to act as a potent multikinase inhibitor by blocking not only the BCR-ABL1 gene sequence but also the SRC kinase family, though unexpected adverse events such as pleural effusion have recently been reported in patients undergoing treatment with dasatinib. Hemorrhagic colitis is a unique gastrointestinal adverse events associated with dasatinib and its pathogenesis remains poorly understood.

CASE PRESENTATION

We report here a case of dasatinib-induced asymptomatic colitis in a patient with CML, who showed no exacerbation in careful observations and maintained deep molecular response (DMR) during a 3-year period. In addition, we performed transcriptome analysis of inflamed colonic mucosa specimens to clarify the possible mechanism of colitis that develops in association with dasatinib administration. Our results demonstrated that differential gene expression, especially lymphocyte-associated genes and chemokines, is substantially involved in inflammation of colonic mucosa in affected patients.

CONCLUSION

Dasatinib induces immune-mediated colitis following lymphocyte infiltration.

Nitrogen-Containing Heterocycles as Anticancer Agents: An Overview

Background:

Cancer is spreading all over the world, and it is becoming the leading cause of major deaths. Today’s most difficult task for every researcher is to invent a new drug that can treat cancer with minimal side effects. Many factors, including pollution, modern lifestyle and food habits, exposure to oncogenic agents or radiations, enhanced industrialization, etc. can cause cancer. Treatment of cancer is done by various methods that include chemotherapy, radiotherapy, surgery and immunotherapy in combination or singly along with kinase inhibitors. Most of the anti-cancer drugs use the concept of kinase inhibition.

Objective:

The number of drugs being used in chemotherapy has heterocycles as their basic structure in spite of various side effects. Medicinal chemists are focusing on nitrogen-containing heterocyclic compounds like pyrrole, pyrrolidine, pyridine, imidazole, pyrimidines, pyrazole, indole, quinoline, oxadiazole, azole, benzimidazole, etc. as the key building blocks to develop active biological compounds. The aim of this study is to attempt to compile a dataset of nitrogen-containing heterocyclic anti-cancer drugs.

Methods:

We adopted a structural search on notorious journal publication websites and electronic databases such as Bentham Science, Science Direct, PubMed, Scopus, USFDA, etc. for the collection of peer-reviewed research and review articles for the present review. The quality papers were retrieved, studied, categorized into different sections, analyzed and used for article writing.

Conclusion:

As per FDA databases, nitrogen-based heterocycles in the drug design are almost 60% of unique small-molecule drugs. Some of the nitrogen-containing heterocyclic anti-cancer drugs are Axitinib, Bosutinib, Cediranib, Dasatanib (Sprycel®), Erlotinib (Tarceva®), Gefitinib (Iressa®), Imatinib (Gleevec®), Lapatinib (Tykerb ®), Linifanib, Sorafenib (Nexavar®), Sunitinib (Sutent®), Tivozanib, etc. In the present review, we shall focus on the overview of nitrogen-containing heterocyclic active compounds as anti-cancer agents.

A Novel Pharmacodynamic Biomarker and Mechanistic Modeling Facilitate the Development of Tovetumab, a Monoclonal Antibody Directed Against Platelet-Derived Growth Factor Receptor Alpha, for Cancer Therapy

Tovetumab (MEDI-575) is a fully human IgG2κ monoclonal antibody that specifically binds to human platelet-derived growth factor receptor alpha (PDGFRα) and blocks receptor signal transduction by PDGF ligands. The affinity of tovetumab determined using surface plasmon resonance technology and flow cytometry demonstrated comparable binding affinity for human and monkey PDGFRα. In single and repeat-dose monkey pharmacokinetic-pharmacodynamic (PK-PD) studies, tovetumab administration resulted in dose-dependent elevation of circulating levels of PDGF-AA, a member of the PDGF ligand family, due to displacement of PDGF-AA from PDGFRα by tovetumab and subsequent blockade of PDGFRα-mediated PDGF-AA degradation. As such, PDGF-AA accumulation is an indirect measurement of receptor occupancy and is a novel PD biomarker for tovetumab. The nonlinear PK of tovetumab and dose-dependent increase in circulating PDGF-AA profiles were well described by a novel mechanistic model, in which tovetumab and PDGF-AA compete for the binding to PDGFRα. To facilitate translational simulation, the internalization half-lives of PDGF-AA and tovetumab upon binding to PDGFRα were determined using confocal imaging to be 14 ± 4 min and 30 ± 8 min, respectively. By incorporating PDGFRα internalization kinetics, the model not only predicted the target receptor occupancy by tovetumab, but also the biologically active agonistic ligand-receptor complex. This work described a novel PD biomarker approach applicable for anti-receptor therapeutics and the first mechanistic model to delineate the in vivo tri-molecular system of a drug, its target receptor, and a competing endogenous ligand, which collectively have been used for optimal dose recommendation supporting clinical development of tovetumab.

Cardiovascular Toxicity of Tyrosine Kinase Inhibitors Used in Chronic Myeloid Leukemia: An Analysis of the FDA Adverse Event Reporting System Database (FAERS)

Tyrosine kinase inhibitors (TKIs), the treatment of choice for chronic myeloid leukemia (CML), can be associated to cardiovascular (CV) adverse events (AEs). A case/non-case study was performed using AE reports registered in the Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) database to compare the risk of CV event reports related to TKIs indicated in the management of chronic myeloid leukemia (CML). Disproportionality of CV event-related TKIs was computed using the Reporting Odds Ratio (ROR) as a measure of potential risk increase. Nilotinib accounts for more than half of reported cases related to TKIs. Signal of Disproportionate Reporting (SDR) was found for cardiac failure, ischemic heart disease, cardiac arrhythmias, torsade de pointes/QT prolongation, hypertension, and pulmonary hypertension. Dasatinib and bosutinib were related to the highest disproportionality for cardiac failure. Nilotinib was associated with the highest SDR for ischemic heart disease, torsade de pointes/QT prolongation and cardiac arrhythmias. Only ponatinib was related to an SDR for hypertension, while dasatinib and imatinib were related to pulmonary hypertension. In the context of CML, TKIs have different safety profiles related to CV events, among which nilotinib seems particularly related to. These results claim for a revision of its CV safety profile mainly for the risk of torsade de pointes/QT prolongation.

Effects of Glycyrrhetic Acid on Human Chronic Myelogenous Leukemia Cells

Objectives

Chronic myelogenous leukemia (CML) is a type of blood cancer that is initially treated with imatinib (first Abl kinase inhibitor). However, some patients with CML develop imatinib resistance. Several new generation drugs have been developed, but do not overcome this problem. Glycyrrhetic acid (GA) is a plant-derived pentacyclic triterpenoid that exhibits multiple pharmacological properties for the treatment of cancers. The current study aimed to investigate the effects of GA on the K562 cell line (Bcr-Abl positive leukemia).

Materials and Methods

The MTT cell proliferation assay was employed to evaluate the cytotoxic effect of GA compared with imatinib (positive control) against leukemia and normal blood cells. For detection of cell death, an apoptotic/necrotic/healthy assay was performed against the K562 cell line. To investigate the kinase inhibitory activity of GA, the Abl1 kinase profiling assay and a molecular docking study were performed.

Results

GA showed Abl kinase inhibitory activity with an IC₅₀ value of 29.2 μM and induced apoptosis in the K562 cell line after 6 h of treatment.

Conclusion

The current findings indicate that this class of plant extract could be a potential candidate for treatment of CML.

Dasatinib Inhibits Procoagulant and Clot Retracting Activities of Human Platelets

Tyrosine kinase inhibitors (TKI) such as the BCR-ABL inhibitor dasatinib and nilotinib are highly effective therapies for chronic myeloid leukemia (CML). However, several lines of evidence suggest that dasatinib can induce bleeding which may be due to impaired collagen-induced platelet adhesion, aggregation, and secretion. Sarcoma family kinases (SFK) play central role in the GPVI-induced signaling pathway. We aimed to investigate whether and how dasatinib can modulate SFK-mediated platelet procoagulant activity in a purified system and in dasatinib/nilotinib treated CML patients. In platelet rich plasmas of healthy volunteers, dasatinib dose-dependently reduced convulxin-induced phosphatidylserine exposure and attenuated thrombin formation. Similarly to these changes, integrin activation and clot retraction were also significantly inhibited by 100 nM dasatinib. Platelets isolated from dasatinib treated patients showed a significantly lower phosphatidylserine expression upon convulxin activation compared to premedication levels. In these samples, thrombin generation was significantly slower, and the quantity of formed thrombin was less compared to the trough sample. Western blot analyses showed decreased phosphorylation levels of the C-terminal tail and the activation loop of SFKs upon dasatinib administration. Taken together, these results suggest that dasatinib inhibits the formation of procoagulant platelets via the GPVI receptor by inhibiting phosphorylation of SFKs.

Tyrosine kinase inhibitor therapy prescribed for non-urologic diseases can modify PSA titers in urology patients

BACKGROUND

The tyrosine kinase inhibitors (TKI), imatinib and nilotinib, are used to treat chronic myelogenous leukemia (CML). In three CML patients being monitored for urologic diseases, we observed that switching of TKI therapy affected prostate-specific antigen (PSA) titers. Urologists and other medical professionals need to be aware of the potential side-effects of drugs that patients may be receiving for other indications to modify this important prostate diseases indicator. TKIs may affect PSA titers independent of prostate growth or volume.

MATERIALS AND METHODS

We followed PSA levels in urology patients who were also undergoing TKI treatment for CML. We determined the effects of nilotinib and imatinib on proliferation, AR and PSA expression in the LNCaP and 22Rv1 prostate cancer (PCa) cell lines using real-time PCR and Western blotting.

RESULTS

Clinically, nilotinib and dasatinib reversibly reduced PSA titers compared to imatinib. At high doses nilotinib and imatinib both demonstrated antiproliferative effects in the PCa cells. At low doses expression of AR and PSA was decreased by both drugs, at mRNA and protein levels. Nilotinib exerted greater effects at lower doses than imatinib.

CONCLUSIONS

Nilotinib down-regulates serum PSA in patients being treated for non-urological indications, potentially masking a clinical useful marker, we cannot exclude a similar but smaller effect of imatinib. Nilotinib and imatinib both decreased AR and PSA expression in PCa cell lines with the nilotinib effect evident at lower doses. Urologists must appreciate the effects of drugs provided for other diseases on PSA titers and be aware that sudden changes may not reflect underlying prostatic disease.

Cancer therapeutic targeting using mutant-p53-specific siRNAs

Mutations in Tp53 compromise therapeutic response, due either to the dominant-negative effect over the functional wild-type allele; or as a result of the survival advantage conferred by mutant p53 to which cancer cells become addicted. Thus, targeting mutant p53 represents an effective therapeutic strategy to treat over half of all cancers. We have therefore generated a series of small-interfering-RNAs, capable of targeting four p53 hot-spot mutants which represent ~20% of all p53 mutations. These mutant–p53-specific siRNAs (MupSi) are highly specific in silencing the expression of the intended mutants without affecting wild-type p53. Functionally, these MupSis induce cell death by abrogating both the addiction to mutant p53 and the dominant-negative effect; and retard tumor growth in xenografts when administered in a therapeutic setting. These data together demonstrate the possibility of targeting mutant p53 specifically to improve clinical outcome.

Simultaneous Determination of Imatinib and N-Desmethyl Imatinib in Rat Plasma and Tissues Using LC-MS/MS

Background:

Imatinib (IM) is a chemotherapy medication metabolized by CYP3A4 to Ndesmethyl imatinib (NDI), which shows similar pharmacologic activity to the parent drug. Although methods for determination of IM and/or NDI have been developed extensively, only few observations have been addressed to simultaneously determine IM and NDI in biological tissues such as liver, kidney, heart, brain and bone marrow.

Methods:

A validated LC-MS/MS method was developed for the quantitative determination of imatinib (IM) and N-desmethyl imatinib (NDI) from rat plasma, bone marrow, brain, heart, liver and kidney. The plasma samples were prepared by protein precipitation, and then the separation of the analytes was achieved using an Agilent Zorbax Eclipse Plus C18 column (4.6 × 100 mm, 3.5 µm) with gradient elution running water (A) and methanol (B). Mass spectrometric detection was achieved by a triplequadrupole mass spectrometer equipped with an electrospray source interface in positive ionization mode.

Results:

This method was used to investigate the pharmacokinetics and the tissue distributions in rats following oral administration of 25 mg/kg of IM. The pharmacokinetic profiles suggested that IM and NDI are disappeared faster in rats than human, and the tissue distribution results showed that IM and NDI had good tissue penetration and distribution, except for the brain. This is the first report about the large penetrations of IM and NDI in rat bone marrow.

Conclusion:

The method demonstrated good sensitivity, accuracy, precision and recovery in assays of IM and NDI in rats. The described assay was successfully applied for the evaluation of pharmacokinetics and distribution in the brain, heart, liver, kidney and bone marrow of IM and NDI after a single oral administration of IM to rats.

Pleural adverse drugs reactions and protein kinase inhibitors: Identification of suspicious targets by disproportionality analysis from VigiBase

AIMS

To evaluate the risk of pleural disorders (PD) associated with 33 protein kinase (PK) inhibitors (PKIs) through a disproportionality analysis and to identify which PKs and pathways are involved in PKI-induced PD.

METHODS

To evaluate the risk of PD, reporting odds ratios (RORs) were calculated for 33 PKIs through data registered in the World Health Organization safety report database (VigiBase). We undertook a literature review to identify PKs that were possibly involved in PD caused by PKIs. Pearson correlation coefficients (r) between RORs and affinity data of 19 PKIs were calculated to identify the cellular target most likely to be involved in PKI-induced PD.

RESULTS

A total of 235 110 individual case safety reports were extracted from the database for 33 available PKIs. Among these reports, 5001 concerned PD (2.1%). Significant and positive disproportionality for PD was found for 29 of 33 PKI included in our study with top values for dasatinib [ROR = 115.3; 95% confidence interval (CI): 110.1-120.8], bosutinib (ROR = 20.4; 95% CI: 15.8-26.4) and ponatinib (ROR = 12; 95% CI: 9.2-15.6). Correlation analyses between the product of dissociation constant and ROR highlighted possibly Lyn involvement in PD with PKI (r = 0.73, P = 0.0004).

CONCLUSIONS

Our study showed that 28 of the 33 tested PKIs were associated with PD. Besides, the study highlighted the role of Lyn in PD caused by PKIs through an immune-mediated process.

BCR-ABL Tyrosine Kinase Inhibitors: Which Mechanism(s) May Explain the Risk of Thrombosis?

Imatinib, the first-in-class BCR-ABL tyrosine kinase inhibitor (TKI), had been a revolution for the treatment of chronic myeloid leukemia (CML) and had greatly enhanced patient survival. Second- (dasatinib, nilotinib, and bosutinib) and third-generation (ponatinib) TKIs have been developed to be effective against BCR-ABL mutations making imatinib less effective. However, these treatments have been associated with arterial occlusive events. This review gathers clinical data and experiments about the pathophysiology of these arterial occlusive events with BCR-ABL TKIs. Imatinib is associated with very low rates of thrombosis, suggesting a potentially protecting cardiovascular effect of this treatment in patients with BCR-ABL CML. This protective effect might be mediated by decreased platelet secretion and activation, decreased leukocyte recruitment, and anti-inflammatory or antifibrotic effects. Clinical data have guided mechanistic studies toward alteration of platelet functions and atherosclerosis development, which might be secondary to metabolism impairment. Dasatinib, nilotinib, and ponatinib affect endothelial cells and might induce atherogenesis through increased vascular permeability. Nilotinib also impairs platelet functions and induces hyperglycemia and dyslipidemia that might contribute to atherosclerosis development. Description of the pathophysiology of arterial thrombotic events is necessary to implement risk minimization strategies.

Addressing the Survivorship Care Needs of Patients Receiving Extended Cancer Treatment

Cancer survivorship care and research has typically focused on the health care needs of people with cancer following the acute phase of treatment. Work in this area, however, has faced challenges in identifying when treatment is complete for many forms of cancer. Acknowledging this challenge, the scope of survivorship research is often expanded to include patients also receiving maintenance or prophylactic therapy. Inherent in this expanded definition is the recognition that for many individuals, cancer is a chronic disease requiring extended treatment over many years. Three distinct patient populations can be identified for which extended treatment poses important survivorship care needs that, to date, have not been adequately addressed. The first group includes patients receiving extended endocrine therapy, such as women with breast cancer receiving tamoxifen and/or aromatase inhibitors as well as men with prostate cancer receiving androgen deprivation therapy. The second group includes patients receiving extended targeted therapy to control disease, as exemplified by patients with chronic myelogenous leukemia receiving treatment with tyrosine kinase inhibitors. A key issue in both of these patient groups is the need to identify and address factors that contribute to difficulties in maintaining high levels of adherence to the prescribed therapy over extended periods of time. The third group includes patients receiving novel therapies for advanced or metastatic cancer that can extend life for prolonged periods. A key issue for this group is the need to understand and address their unique supportive care needs.

Long-term bosutinib for chronic phase chronic myeloid leukemia after failure of imatinib plus dasatinib and/or nilotinib

Bosutinib is an Src/Abl tyrosine kinase inhibitor (TKI) indicated for adults with Ph+ chronic myeloid leukemia (CML) resistant/intolerant to prior TKIs. This long-term update of an ongoing phase 1/2 study evaluated the efficacy and safety of third-/fourth-line bosutinib in adults with chronic phase (CP) CML. Median durations of treatment and follow-up were 8.6 (range, 0.2-87.7) months and 32.7 (0.3-93.3) months, respectively. Cumulative confirmed complete hematologic response (cCHR) and major cytogenetic response (MCyR) rates were 74% (95% CI, 65-81%) and 40% (31-50%), respectively; Kaplan-Meier (K-M) probability of maintaining cCHR or MCyR at 4 years was 63% (95% CI, 50-73%) and 69% (52-81%). Cumulative incidence of on-treatment disease progression (PD)/death at 4 years was 24% (95% CI, 17-33%); K-M 4-year overall survival was 78% (68-85%). Baseline Ph+ cells ≤35 vs. ≥95% was prognostic of MCyR and CCyR by 3 and 6 months, increased baseline basophils was prognostic of PD/death, and no prior response to second-line TKI was prognostic of death. Common adverse events included diarrhea (83%), nausea (48%), vomiting (38%), and thrombocytopenia (39%). Bosutinib demonstrates durable efficacy and a toxicity profile similar to previous bosutinib studies in CP CML patients resistant/intolerant to multiple TKIs, representing an important treatment option for patients in this setting. This trial is registered at www.clinicaltrials.gov (NCT00261846). Am. J. Hematol. 91:1206-1214, 2016. © 2016 Wiley Periodicals, Inc.

A proof-of-concept study with the tyrosine kinase inhibitor nilotinib in spondyloarthritis

Background

To evaluate the immunomodulating and clinical effects of nilotinib, a tyrosine kinase inhibitor, in a proof-of-concept study in spondyloarthritis (SpA) assessing the mast cell as potential novel therapeutic target in this disease.

Methods

Twenty eight patients with active peripheral (pSpA) and/or axial SpA (axSpA) were included in a randomized, double-blind, placebo-controlled clinical trial (Trial registration: Trialregister.nl NTR2834). Patients were treated 1:1 with nilotinib or placebo for 12 weeks, followed by an open label extension for another 12 weeks. Paired synovial tissue biopsies, serum sampling and assessment of clinical symptoms were performed serially.

Results

In pSpA (n = 13) synovial inflammation appeared to diminish after 12 weeks of nilotinib treatment as evidenced by histopathology (decrease in number of infiltrating CD68+ and CD163+ macrophages and mast cells). Compared to placebo mRNA expression of c-Kit as mast cell marker (p = 0.037) and of pro-inflammatory cytokines such as IL-6 (p = 0.024) were reduced. The reduction of synovial inflammation was paralleled by a decrease in serum biomarkers of inflammation such as C-reactive protein (p = 0.024) and calprotectin (p = 0.055). Also clinical parameters such as patient’s global assessment of disease activity (p = 0.031) and ankylosing spondylitis disease activity score (p = 0.031) showed improvement upon 12 weeks of nilotinib but not placebo treatment. This improvement was further augmented at week 24. In contrast to pSpA, neither serum biomarkers of inflammation nor clinical parameters improved upon nilotinib treatment in axSpA. During the trial one serious adverse event occurred, which was considered unrelated to the study drug.

Conclusions

This small proof-of-concept study suggests that nilotinib treatment modulates inflammation and clinical symptoms in pSpA. A similar effect was not seen in axSpA.

Trial registration: trialregister.nl registration code NTR2834 registered 31 March 2011

The development of agents targeting the BCR-ABL tyrosine kinase as Philadelphia chromosome-positive acute lymphoblastic leukemia treatment

INTRODUCTION

In Philadelphia chromosome-positive (Ph⁺) acute lymphoblastic leukemia (ALL), the BCR-ABL translocation is the main transforming event; consequently, it is targeted by ABL-tyrosine kinase inhibitors (TKIs), the first of which to be identified was imatinib mesylate. There are now four newer TKIs, three so-called second-generation inhibitors and one third generation inhibitor, all of which are more potent than imatinib in in vitro assays. Areas covered: This paper reviews the current knowledge on the function of BCR-ABL. Furthermore, this paper highlights the impact of this knowledge on the development of a targeted therapy approach in Ph⁺ ALL and the obstacles for the successful treatment with these drugs. Expert opinion: Identifying key components involved in disease pathogenesis may lead to new approaches that might overcome resistance mediated to the BCR-ABL TKIs. In a near future, the authors believe that monoclonal antibodies and immunotherapy should also be combined with TKIs and up-front chemotherapy for the successful treatment of ALL.

Disseminated intravascular coagulation following administration of sunitinib

Sunitinib is an increasingly used, orally administered targeted therapy, approved by the European Medicines Agency for the treatment of various types of cancer, including gastrointestinal stromal tumor unresectable or metastatic disease, following disease progression or intolerance to imatinib, and advanced or metastatic renal cell carcinoma, progressive well-differentiated pancreatic neuroendocrine tumors in patients with unresectable, locally advanced or metastatic disease. Sunitinib inhibits several tyrosine kinases, including the vascular endothelial growth factor receptor and the platelet-derived growth factor receptor. Tyrosine kinases inhibitor therapies are generally well-tolerated; nonetheless, they are not void of side effects. The majority of patients reported are grade 1 or 2, and include common and unspecific adverse events, including fatigue, gastrointestinal disorders, skin discoloration, altered taste, cough and dyspnea. Grade 3 or 4 adverse events, including bleeding and hemorrhage, are less frequent. The present study presented the first case of disseminated intravascular coagulation associated with the administration of sunitinib, shortly following the increase of sunitinib dosage.

EphB4-VAV1 signaling pathway is associated with imatinib resistance in chronic myeloid leukemia cells

Imatinib (IM) resistant Chronic Myeloid Leukemia (CML) is an important issue to be addressed while treating CML patients. The present study analyzes the role of EphB4-VAV1 signaling in IM-resistant CML. EphB4 and VAV1 were overexpressed in IM-resistant CML patients and K562-R cell line (K562-R). Then, we established stable under-expressing EphB4 cell line K562-R-EphB4-sh. VAV1 was down-regulated in K562-R-EphB4-sh cells. K562-R-EphB4-sh cells gained re-sensitivity to IM and K562-R cells showed mild IM resistance. However, EphB4 was no changed when the VAV1 was down-regulated. EphB4 and VAV1 were overexpressed in IM-resistant CML, VAV1might be the downstream moleculars of EphB4. These results suggest a potential role of EphB4-VAV1 signaling as therapeutic target of IM-resistant CML.

Adverse events associated with tyrosine kinase inhibitors for the treatment of chronic myeloid leukemia

INTRODUCTION

Tyrosine kinase inhibitors (TKIs) drastically changed the outcome of patients affected by chronic myeloid leukemia, allowing long-term improved overall survival and deep molecular responses.

AREAS COVERED

In this review, all the related and "off target" side effects of different TKIs are reported and reviewed including their pathogenesis, and associated predisposing factors are discussed.

EXPERT OPINION

Appropriate identification of adverse events and classification according to CTC scale is required during therapy with TKI, considering the impact on the long-term quality of life. Specific evaluation and stratification of comorbidities and cardiovascular risk profile at baseline is suggested in order to better tailor individualized treatment strategy and identify patients who require strict monitoring of risk factors during treatment.

Lung cancer: Biology and treatment options

Lung cancer remains the leading cause of cancer mortality in men and women in the U.S. and worldwide. About 90% of lung cancer cases are caused by smoking and the use of tobacco products. However, other factors such as radon gas, asbestos, air pollution exposures, and chronic infections can contribute to lung carcinogenesis. In addition, multiple inherited and acquired mechanisms of susceptibility to lung cancer have been proposed. Lung cancer is divided into two broad histologic classes, which grow and spread differently: small-cell lung carcinomas (SCLCs) and non-small cell lung carcinomas (NSCLCs). Treatment options for lung cancer include surgery, radiation therapy, chemotherapy, and targeted therapy. Therapeutic-modalities recommendations depend on several factors, including the type and stage of cancer. Despite the improvements in diagnosis and therapy made during the past 25 years, the prognosis for patients with lung cancer is still unsatisfactory. The responses to current standard therapies are poor except for the most localized cancers. However, a better understanding of the biology pertinent to these challenging malignancies, might lead to the development of more efficacious and perhaps more specific drugs. The purpose of this review is to summarize the recent developments in lung cancer biology and its therapeutic strategies, and discuss the latest treatment advances including therapies currently under clinical investigation.

MET Gene Amplification and MET Receptor Activation Are Not Sufficient to Predict Efficacy of Combined MET and EGFR Inhibitors in EGFR TKI-Resistant NSCLC Cells

Epidermal growth factor receptor (EGFR), member of the human epidermal growth factor receptor (HER) family, plays a critical role in regulating multiple cellular processes including proliferation, differentiation, cell migration and cell survival. Deregulation of the EGFR signaling has been found to be associated with the development of a variety of human malignancies including lung, breast, and ovarian cancers, making inhibition of EGFR the most promising molecular targeted therapy developed in the past decade against cancer. Human non small cell lung cancers (NSCLC) with activating mutations in the EGFR gene frequently experience significant tumor regression when treated with EGFR tyrosine kinase inhibitors (TKIs), although acquired resistance invariably develops. Resistance to TKI treatments has been associated to secondary mutations in the EGFR gene or to activation of additional bypass signaling pathways including the ones mediated by receptor tyrosine kinases, Fas receptor and NF-kB. In more than 30–40% of cases, however, the mechanisms underpinning drug-resistance are still unknown. The establishment of cellular and mouse models can facilitate the unveiling of mechanisms leading to drug-resistance and the development or validation of novel therapeutic strategies aimed at overcoming resistance and enhancing outcomes in NSCLC patients. Here we describe the establishment and characterization of EGFR TKI-resistant NSCLC cell lines and a pilot study on the effects of a combined MET and EGFR inhibitors treatment. The characterization of the erlotinib-resistant cell lines confirmed the association of EGFR TKI resistance with loss of EGFR gene amplification and/or AXL overexpression and/or MET gene amplification and MET receptor activation. These cellular models can be instrumental to further investigate the signaling pathways associated to EGFR TKI-resistance. Finally the drugs combination pilot study shows that MET gene amplification and MET receptor activation are not sufficient to predict a positive response of NSCLC cells to a cocktail of MET and EGFR inhibitors and highlights the importance of identifying more reliable biomarkers to predict the efficacy of treatments in NSCLC patients resistant to EGFR TKI.

An immunosuppressive antibody-drug conjugate

We have developed a novel antibody-drug conjugate (ADC) that can selectively deliver the Lck inhibitor dasatinib to human T lymphocytes. This ADC is based on a humanized antibody that selectively binds with high affinity to CXCR4, an antigen that is selectively expressed on hematopoietic cells. The resulting dasatinib-antibody conjugate suppresses T-cell-receptor (TCR)-mediated T-cell activation and cytokine expression with low nM EC50 and has minimal effects on cell viability. This ADC may lead to a new class of selective immunosuppressive drugs with improved safety and extend the ADC strategy to the targeted delivery of kinase inhibitors for indications beyond oncology.

Different role of cAMP pathway on the human mast cells HMC-1(560) and HMC-1(560,816) activation

HMC-1 are inflammatory cells that release vasoactive substances such as histamine. These cells have the c-kit receptor permanently activated in the membrane due to mutations in the proto-oncogene c-kit: Val-560 → Gly and Asp-816 → Val. Thus, there are two known cellular lines: HMC-1(560) and HMC-1(560,816) . These mutations are involved in a disease called mastocitosys. In the present paper both lines were used to study the influence of cAMP/PKA/PDEs pathway on the histamine release and Ca(2+) signaling since this pathway is often involved in these process. For this, the cells were preincubated with cAMP/PKA/PDEs modulators such as dibutyryl cAMP (dbcAMP), forskolin, H89, rolipram, IBMX, or imidazole and then stimulated with ionomycin. When cells were stimulated with agents that increase cAMP levels, the histamine release was not modified in HMC-1(560) but decreased in HMC-1(560,816) cells. The same happened when PKA was blocked. Furthermore, PDEs role on histamine release was independent of cAMP in HMC-1(560) cells and possibly also in HMC-1(560,816) cells. By contrast, the modulation of PKA and PDEs together changed the response in both cellular lines, therefore a relationship between them was suggested. All these modulatory effects on histamine release are Ca(2+) -independent. On the other hand, the effect of c-kit modulation on the cAMP/PKA/PDEs pathway was also checked. This receptor was blocked with STI571 (imatinib) and BMS-354825 (dasatinib), but only the last one caused a decrease in the cellular response to ionomycin. This article demonstrates for the first time than the cAMP/PKA/PDEs pathway is involved in the activation of HMC-1(560) and HMC-1(560,816) cells.

Guide to interpreting disease responses in chronic myeloid leukemia

With the introduction of tyrosine kinase inhibitor (TKI) therapy for chronic myeloid leukemia, the course of the disease has been altered from an acute, rapidly progressive terminal disorder to a serious condition with high remission rates when patients are compliant with long-term treatment. The goal of therapy is to prevent transformation to the accelerated or blast crisis phases, which are associated with poor survival. Knowledge of the appropriate monitoring tests and treatment milestones, as well as the ability to interpret responses, allows advanced practitioners (APs) to effectively communicate key aspects of management to their patients. Monitoring patient responses to TKIs and identifying suboptimal responses early on offer APs the opportunity to reevaluate and adjust therapeutic treatment options. One of the causes of treatment failure is noncompliance; thus, educating patients on the importance of adhering to treatment and identifying reasons for noncompliance are of major importance. Because intolerance to TKIs may lead to discontinuation, frequent monitoring of side effects and response to treatment, open communication, patient education, and careful management are all essential in helping patients remain compliant with therapy. This review discusses the AP's role in helping patients achieve their best response to TKI therapy and optimize their long-term outcomes.