Management of adverse events associated with tyrosine kinase inhibitors in the treatment of chronic myeloid leukemia

Therapeutic advances of targeting receptor tyrosine kinases in cancer

Receptor tyrosine kinases (RTKs), a category of transmembrane receptors, have gained significant clinical attention in oncology due to their central role in cancer pathogenesis. Genetic alterations, including mutations, amplifications, and overexpression of certain RTKs, are critical in creating environments conducive to tumor development. Following their discovery, extensive research has revealed how RTK dysregulation contributes to oncogenesis, with many cancer subtypes showing dependency on aberrant RTK signaling for their proliferation, survival and progression. These findings paved the way for targeted therapies that aim to inhibit crucial biological pathways in cancer. As a result, RTKs have emerged as primary targets in anticancer therapeutic development. Over the past two decades, this has led to the synthesis and clinical validation of numerous small molecule tyrosine kinase inhibitors (TKIs), now effectively utilized in treating various cancer types. In this manuscript we aim to provide a comprehensive understanding of the RTKs in the context of cancer. We explored the various alterations and overexpression of specific receptors across different malignancies, with special attention dedicated to the examination of current RTK inhibitors, highlighting their role as potential targeted therapies. By integrating the latest research findings and clinical evidence, we seek to elucidate the pivotal role of RTKs in cancer biology and the therapeutic efficacy of RTK inhibition with promising treatment outcomes.

From Tyrosine Kinases to Tyrosine Phosphatases: New Therapeutic Targets in Cancers and Beyond

Protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs) regulate the level of tyrosine phosphorylation in proteins. PTKs are key enzymes that catalyze the transfer of an ATP phosphoric acid to a tyrosine residue on target protein substrates. Protein tyrosine phosphatases (PTPs) are responsible for the dephosphorylation of tyrosine residues and play a role in countering PTK overactivity. As widespread oncogenes, PTKs were once considered to be promising targets for therapy. However, tyrosine kinase inhibitors (TKIs) now face a number of challenges, including drug resistance and toxic side effects. Treatment strategies now need to be developed from a new perspective. In this review, we assess the current state of TKIs and highlight the role of PTPs in cancer and other diseases. With the advances of allosteric inhibition and the development of multiple alternative proprietary drug strategies, the reputation of PTPs as "undruggable" targets has been overturned, and they are now considered viable therapeutic targets. We also discuss the strategies and prospects of PTP-targeted therapy, as well as its future development.

Effect of Tyrosine Kinase Inhibitor Therapy on Estimated Glomerular Filtration Rate in Patients with Chronic Myeloid Leukemia

INTRODUCTION

The advent of tyrosine kinase inhibitors (TKIs) was revolutionary in the management of chronic myeloid leukemia (CML). Although TKIs were generally considered to be safe, they can be associated with renal injury. We evaluated the effect of TKIs on renal functions in a cohort of patients with long-term follow-up.

MATERIAL AND METHODS

We retrospectively examined patients with chronic phase CML treated with TKIs. We analyzed the estimated glomerular filtration rate (eGFR) of patients from the initiation of TKI to the last follow-up. eGFR values of CML patients were compared to those of patients with stage 1 or 2 chronic kidney disease (CKD).

RESULTS

A total of 195 patients with CML and 138 patients with CKD were examined. eGFR decline was 1.556 ml/min/1.73m2/year for patients with CML (P = .221). Patients receiving second-generation TKIs (2GTKI) were estimated to have 0.583 ml/min/1.73m2 higher eGFR value than that of the imatinib group, but it was not significant (P = .871). eGFR of patients who had used bosutinib had a downward trend. Duration of TKI therapy, age, and hypertension were found to be significant factors in eGFR decline for CML patients. Lower baseline GFR was associated with an increased risk of CKD development.

CONCLUSION

Imatinib could result in a decline in eGFR which was clinically similar to early-stage CKD patients. We did not observe significant kidney function deterioration in patients receiving 2GTKIs including dasatinib and nilotinib. We recommend close renal function monitoring in patients receiving imatinib, especially for elderly patients with lower baseline eGFR and hypertension.

Anti-CD19 CAR T-cell consolidation therapy combined with CD19+ feeding T cells and TKI for Ph+ acute lymphoblastic leukemia

We conducted a single-arm, open-label, single-center phase 1 study to assess the safety and efficacy of multicycle-sequential anti-CD19 chimeric antigen receptor (CAR) T-cell therapy in combination with autologous CD19+ feeding T cells (FTCs) and tyrosine kinase inhibitor (TKI) as consolidation therapy in patients under the age of 65 years with de novo Ph-positive CD19+ B-cell acute lymphoblastic leukemia. Participants were given induction chemotherapy as well as systemic chemotherapy with TKI. Afterward, they received a single cycle of CD19 CAR T-cell infusion and another 3 cycles of CD19 CAR T-cell and CD19+ FTC infusions, followed by TKI as consolidation therapy. CD19+ FTCs were given at 3 different doses. The phase 1 results of the first 15 patients, including 2 withdrawals, are presented. The most common adverse events were cytopenia (13/13) and hypogammaglobinemia (12/13). There was no incidence of cytokine release syndrome above grade 2 or immune effector cell-associated neurotoxicity syndrome or grade 4 nonhematological toxicities. All 13 patients achieved complete remission, including 12 patients with a complete molecular response (CMR) at the data cutoff. The relapse-free survival was 84%, and the overall survival was 83% with a median follow-up of 27 months. The total number of CD19-expressing cells decreased with an increasing CMR rate. CD19 CAR T cells survived for up to 40 months, whereas CD19+ FTCs vanished in 8 patients 3 months after the last infusion. These findings could form the basis for the development of an allo-HSCT-free consolidation paradigm. This trial was registered at www.clinicaltrials.gov as #NCT03984968.

Adverse effects of tyrosine kinase inhibitors in cancer therapy: pathophysiology, mechanisms and clinical management

Since their invention in the early 2000s, tyrosine kinase inhibitors (TKIs) have gained prominence as the most effective pathway-directed anti-cancer agents. TKIs have shown significant utility in the treatment of multiple hematological malignancies and solid tumors, including chronic myelogenous leukemia, non-small cell lung cancers, gastrointestinal stromal tumors, and HER2-positive breast cancers. Given their widespread applications, an increasing frequency of TKI-induced adverse effects has been reported. Although TKIs are known to affect multiple organs in the body including the lungs, liver, gastrointestinal tract, kidneys, thyroid, blood, and skin, cardiac involvement accounts for some of the most serious complications. The most frequently reported cardiovascular side effects range from hypertension, atrial fibrillation, reduced cardiac function, and heart failure to sudden death. The potential mechanisms of these side effects are unclear, leading to critical knowledge gaps in the development of effective therapy and treatment guidelines. There are limited data to infer the best clinical approaches for the early detection and therapeutic modulation of TKI-induced side effects, and universal consensus regarding various management guidelines is yet to be reached. In this state-of-the-art review, we examine multiple pre-clinical and clinical studies and curate evidence on the pathophysiology, mechanisms, and clinical management of these adverse reactions. We expect that this review will provide researchers and allied healthcare providers with the most up-to-date information on the pathophysiology, natural history, risk stratification, and management of emerging TKI-induced side effects in cancer patients.

Small Molecule Inhibitors as Therapeutic Agents Targeting Oncogenic Fusion Proteins: Current Status and Clinical

Oncogenic fusion proteins, arising from chromosomal rearrangements, have emerged as prominent drivers of tumorigenesis and crucial therapeutic targets in cancer research. In recent years, the potential of small molecular inhibitors in selectively targeting fusion proteins has exhibited significant prospects, offering a novel approach to combat malignancies harboring these aberrant molecular entities. This review provides a comprehensive overview of the current state of small molecular inhibitors as therapeutic agents for oncogenic fusion proteins. We discuss the rationale for targeting fusion proteins, elucidate the mechanism of action of inhibitors, assess the challenges associated with their utilization, and provide a summary of the clinical progress achieved thus far. The objective is to provide the medicinal community with current and pertinent information and to expedite the drug discovery programs in this area.

Drug-related immune-mediated myelopathies

Iatrogenic immune-mediated inflammatory disorders of the spinal cord are an uncommon but potentially severe complication of drug therapy for several human diseases. Particularly the introduction of novel biological agents in the treatment of systemic inflammatory disorders and cancer immunotherapy have led to a significant increase in immune-related adverse events of the central nervous system (CNS). The use of Tumor necrosis factor alpha (TNF-alpha) inhibitors in rheumatic and inflammatory bowel diseases has been associated with demyelinating and other inflammatory CNS conditions, including myelitis. The introduction of immune checkpoint inhibitors in the treatment of several human malignancies has led to an increase in drug-induced immune-related adverse events including in the CNS. Other drugs that have been associated with immune-mediated myelitis include tyrosine-kinase inhibitors and chimeric antigen receptor (CAR) T Cell therapy. A high degree of suspicion is necessary when diagnosing these conditions, as early diagnosis and treatment is crucial in preventing further neurological damage and disability. The treatment of drug-induced inflammatory myelitis typically involves administration of high-dose intravenous corticosteroids, however additional immunosuppressive agents may be required in severe or refractory cases. While most cases are monophasic and remit following discontinuation of the offending agent, chronic immunosuppressive therapy may be indicated in cases with a progressive or relapsing disease course or when a diagnosis of a specific underlying neuro-inflammatory disorder is made. Outcomes are generally favorable, however depend on the specific therapeutic agent used, the clinical presentation and patient factors. In this review we aim to describe the clinical characteristics, imaging findings and management for the most common forms of iatrogenic immune-mediated myelopathies.

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

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

Comparison of Anticancer Drug Toxicities: Paradigm Shift in Adverse Effect Profile

The inception of cancer treatment with chemotherapeutics began in the 1940s with nitrogen mustards that were initially employed as weapons in World War II. Since then, treatment options for different malignancies have evolved over the period of last seventy years. Until the late 1990s, all the chemotherapeutic agents were small molecule chemicals with a highly nonspecific and severe toxicity spectrum. With the landmark approval of rituximab in 1997, a new horizon has opened up for numerous therapeutic antibodies in solid and hematological cancers. Although this transition to large molecules improved the survival and quality of life of cancer patients, this has also coincided with the change in adverse effect patterns. Typically, the anticancer agents are fraught with multifarious adverse effects that negatively impact different organs of cancer patients, which ultimately aggravate their sufferings. In contrast to the small molecules, anticancer antibodies are more targeted toward cancer signaling pathways and exhibit fewer side effects than traditional small molecule chemotherapy treatments. Nevertheless, the interference with the immune system triggers serious inflammation- and infection-related adverse effects. The differences in drug disposition and interaction with human basal pathways contribute to this paradigm shift in adverse effect profile. It is critical that healthcare team members gain a thorough insight of the adverse effect differences between the agents discovered during the last twenty-five years and before. In this review, we summarized the general mechanisms and adverse effects of small and large molecule anticancer drugs that would further our understanding on the toxicity patterns of chemotherapeutic regimens.

Dasatinib-Induced Pleural and Pericardial Effusions

Chronic myeloid leukemia (CML) is a myeloproliferative disease associated with the Philadelphia chromosome and BCR-ABL1 fusion gene. Tyrosine kinase inhibitors (TKI) are now the standard therapy for this condition. Among the approved TKIs for CML is dasatinib. We present a case of a 58-year-old Egyptian male who developed bilateral pleural (grade II) as well as pericardial effusions (grade II) secondary to dasatinib 100 mg once-daily dosing. He was managed by interrupting dasatinib and introducing diuretics and steroids. The objective is to raise awareness about this unfavorable effect as it may affect the patient's quality of life and increase rates of treatment withdrawal.

Dasatinib—A Generation Ahead

Dasatinib is a highly potent second-generation (2G) tyrosine kinase inhibitor (TKI) used in the management of Philadelphia (Ph) chromosome-positive leukemias, chronic myeloid leukemia (CML) and acute lymphoblastic leukemia (ALL). In CML, dasatinib produces higher rates of early and deeper molecular responses compared with imatinib. The drug has its share of toxicities, namely, cytopenias, cardiovascular, and pleural effusion. This review describes the pharmacological aspects of dasatinib, clinically relevant toxicities, and their management.

A Pilot Study on Probing of Imatinib Induced Platelet Dysfunction in Patients with Chronic Myeloid Leukemia-Chronic Phase and Absence of Associated Bleeding Manifestation: Trying to Solve an Enigma

Imatinib, the first Tyrosine Kinase Inhibitor (TKI) used for the treatment of chronic myeloid leukaemia (CML) has revolutionized the management by inhibiting BCR-ABL tyrosine kinase. According to earlier reports there are concerns regarding the adverse effect of imatinib on haemostasis by causing platelet dysfunction. Here we studied platelet function using platelet aggregometry, in 19 CML chronic phase (CML-CP) patients on imatinib therapy, in complete haematologic response (CHR). The median duration of imatinib therapy before performing the test was 154 days. This study reveals that there are large inter-individual variations in platelet functions among imatinib treated patients and different levels of variability have been seen for different agonists. Most common aggregation abnormality (< 50% aggregation) was seen with low dose collagen (1 μg/ml) in 31.57% patients. Despite in-vitro platelet aggregation defects, none of the patients showed any bleeding symptoms. This enigma can possibly be explained by the fact that platelet specific agonists, epinephrine and collagen act in synergy for platelet aggregation compared against individual low dose agonists, supported by ex-vivo experiments in normal healthy control group (n = 5) (p value < 0.0004 for epinephrine, p value < 0.0001 for collagen). This experiment was also confirmed in a CML-CP patient. In future, more studies are needed to find out the exact mechanism of this inhibition.

Overview of the Side-Effects of FDA- and/or EMA-Approved Targeted Therapies for the Treatment of Hematological Malignancies

In the last decade there has been tremendous effort in offering better therapeutic management strategies to patients with hematologic malignancies. These efforts have ranged from biological to clinical approaches and resulted in the rapid development of new approaches. The main “problem” that comes with the high influx of newly approved drugs, which not only influences hematologists that frequently work with these drugs but also affects other healthcare professionals that work with hematologists in patient management, including intensive care unit (ICU) physicians, is they have to keep up within their specialty and, in addition, with the side-effects that can occur when encountering hematology-specific therapies. Nonetheless, there are few people that have an in-depth understanding of a specialty outside theirs. Thus, this manuscript offers an overview of the most common side-effects caused by therapies used in hematology nowadays, or that are currently being investigated in clinical trials, with the purpose to serve as an aid to other specialties. Nevertheless, because of the high amount of information on this subject, each chapter will offer an overview of the side-effects of a drug class with each reference of the section being intended as further reading.

Expression of PDK-1 and DMBT1 in the thyroid carcinoma and its clinicopathological significance

This study was designed to explore the expression of phosphoinositide-dependent protein kinase 1 (PDK-1), deleted in malignant brain tumors (DMBT1) in the thyroid carcinoma. A total of 87 fresh samples of thyroid carcinoma from surgical resection in The Second People's Hospital of Lianyungang from June 2016 to March 2018 were collected for the ELISA to detect the protein expression of PDK-1 and DMBT1. Then the pathological significance of the expression of PDK-1 and DMBT1 in the thyroid carcinoma and the correlation between them were analyzed, using the ROC curve to study the diagnostic value of each index. The expression of PDK-1 in the thyroid carcinoma tissue was significantly higher than that in the normal thyroid tissue with a statistical difference between them (P<0.05); the expression of DMBT1 in the thyroid carcinoma was statistically significantly lower than that in the normal thyroid tissue (P<0.05); the PDK-1 and DMBT1 expressions were in negative correlation in the thyroid carcinoma (r=−0.889, P<0.001). The AUG, specificity and the sensitivity of the PDK-1 in diagnosing the thyroid carcinoma were 0.862, 86.21% and 78.16%, respectively; the AUG, specificity and the sensitivity of the DMBT1 in diagnosing the thyroid carcinoma were 0.708, 66.67% and 67.82%, respectively; while the AUG, the specificity and the sensitivity of the combination of PDK-1 and DMBT1 in diagnosing the thyroid carcinoma were 0.888, 89.66% and 81.61%. In conclusion, the occurrence and progression of the thyroid carcinoma were related to the high expression of the PDK-1 and the low expression of the DMBT1 in the thyroid carcinoma tissues, the two of which were in connection with factors involving lymph node metastasis, pathological type, neoplasm staging, and clinical staging. Thus, the combined detection of PDK-1 and DMBT1 could be used as an effective index to determine the occurrence of thyroid carcinoma.

Longer treatment duration and history of osteoarticular symptoms predispose to tyrosine kinase inhibitor withdrawal syndrome

The effectiveness of tyrosine kinase inhibitors (TKIs) has made it possible to consider treatment discontinuation in chronic myeloid leukaemia (CML) patients that achieve an excellent response. However, a few of the patients included in the Europe Stop Tyrosine Kinase Inhibitors (EURO-SKI) trial reported musculoskeletal pain shortly after stopping TKIs, considered as a withdrawal syndrome (WS). To identify factors that may predispose to TKI WS, we analysed the pharmacovigilance declarations for the 6 months after stopping TKIs in a large cohort of CML (n = 427) that combined the French patients included in the STop IMatinib 2 (STIM2; n = 224) and EURO-SKI (n = 203) trials. Among these patients, 23% (99/427) developed TKI WS after stopping imatinib (77/373; 20·4%), nilotinib (12/29; 41·4%) or dasatinib (10/25; 40%). WS concerned mainly the upper body joints, and required multiple symptomatic treatments in 30% of patients. Univariate and multivariate analyses identified two risk factors: duration of TKI treatment [risk ratio (RR) = 1·68 (1·02-2·74)] with a 93-month cut-off time, and history of osteoarticular symptoms [RR = 1·84 (1·04-3·28)]. These findings confirm that WS is a TKI class effect. CML patients should be carefully screened before treatment initiation to identify pre-existent osteoarticular symptoms. Moreover, before TKI discontinuation, patients should be informed of the possibility of WS, particularly after a long treatment period.

[The use of tumor therapeutics in the perioperative period]

In 2010 Germany had 447,300 new cases of cancer. From 2000 to 2010 the incidence of cancer increased by 21% in men and by 14% in women. The change in the age structure with an aging population is the crucial influencing factor. Various cancer types can now be treated by oral antitumor agents used as a chronic medication. Physicians must decide whether the oral antitumor agents can be continued perioperatively or if certain drugs must be paused and if so, with what risks. Oral antitumor agents are a very heterogeneous group of medication. The use of oral antitumor agents during the perioperative period has not been thoroughly examined, but most often a perioperative interruption is recommended. In general, poor wound healing is a frequent complication of this group of medication. The handling of oral antitumor agents in the perioperative period should be based on an individual decision with consideration of the desired therapy goal as well as the individual prognosis. In general, all oral antitumor agents are chronic medication and are continued until a loss of efficacy or intolerable side effects occur. A potentially curative therapy should be paused for the shortest possible time in order not to jeopardize the remission already achieved. Furthermore, generally accepted recommendations concerning the interval between chemotherapy and a planned operation have not yet been established. A rough rule of thumb could be to plan the operation after the regeneration of the blood count or at the same point in time of the next planned chemotherapy.

Haematological adverse events associated with tyrosine kinase inhibitors in chronic myeloid leukaemia: A network meta-analysis

AIMS

Despite their overall favourable safety profile, tyrosine kinase inhibitors (TKIs) are related to severe adverse events including haematological toxicities such as anaemia, leucopenia, neutropenia and thrombocytopenia. We designed a systematic review and network meta-analysis of randomised controlled trials to compare safety among TKIs (bosutinib, dasatinib, imatinib, nilotinib, ponatinib and radotinib) used by patients diagnosed with chronic myeloid leukaemia.

METHODS

We obtained data from the PubMed, Scopus, Web of Science, and SciELO databases. The Bayesian approach was used for direct and indirect comparisons, and the treatments were ranked by the surface under the cumulative ranking curve (SUCRA).

RESULTS

Seventeen studies were included in the network meta-analysis. Our data show that dasatinib was generally considered worse than the other TKIs, with SUCRA values ​​for 140 mg dasatinib of 90.3% for anaemia, 87.4% for leucopenia, 90.6% for neutropenia and 97.2% for thrombocytopenia. In addition, nilotinib was shown to be safer, with SUCRA values ​​for 600 and 800 mg doses of 21.9 and 35.8% for anaemia, 23.8 and 14.6% for leucopenia, 33.0 and 17.7% for neutropenia, and 28.7 and 32.6% for thrombocytopenia, respectively.

CONCLUSION

Dasatinib appeared as the least safe drug for chronic myeloid leukaemia, probably because it binds to multiple key kinase targets, being more prone to cause serious haematological adverse events. Nilotinib demonstrated a safer profile, mostly due to its selective binding capacity.

Front-line imatinib treatment in children and adolescents with chronic myeloid leukemia: results from a phase III trial

A total of 156 patients (age range 1.3-18.0 years, median 13.2 years; 91 (58.3%) male) with newly diagnosed CML (N = 146 chronic phase (CML-CP), N = 3 accelerated phase (CML-AP), N = 7 blastic phase (CML-BP)) received imatinib up-front (300, 400, 500 mg/m², respectively) within a prospective phase III trial. Therapy response, progression-free survival, causes of treatment failure, and side effects were analyzed in 148 children and adolescents with complete data. Event-free survival rate by 18 months for patients in CML-CP (median follow-up time 25 months, range: 1-120) was 97% (95% CI, 94.2-99.9%). According to the 2006 ELN-criteria complete hematologic response by month 3, complete cytogenetic response (CCyR) by month 12, and major molecular response (MMR) by month 18 were achieved in 98, 63, and 59% of the patients, respectively. By month 36, 86% of the patients achieved CCyR and 74% achieved MMR. Thirty-eight patients (27%) experienced imatinib failure because of unsatisfactory response or intolerance (N = 9). In all, 28/148 patients (19%) underwent stem cell transplantation (SCT). In the SCT sub-cohort 2/23 patients diagnosed in CML-CP, 0/1 in CML-AP, and 2/4 in CML-BP, respectively, died of relapse (N = 3) or SCT-related complications (N = 2). This large pediatric trial extends and confirms data from smaller series that first-line imatinib in children is highly effective.

Plasma concentrations of dasatinib have a clinical impact on the frequency of dasatinib dose reduction and interruption in chronic myeloid leukemia: an analysis of the DARIA 01 study

Background

Dasatinib has shown promising anti-leukemic activity against chronic myeloid leukemia (CML). However, patients receiving dasatinib frequently require dose reductions and treatment interruptions (treatment alteration).

Methods

We prospectively analyzed the frequency and significance of treatment alteration during dasatinib therapy in patients with CML. In all patients, trough plasma concentrations of dasatinib (C_min) at steady state were assessed on day 28 of therapy.

Results

28% of patients had their doses reduced at a median of 42 days, and 25% of patients had temporarily interrupted at a median of 54 days after treatment initiation. The overall dasatinib treatment alteration-free rate at 1 year was 66%. Age was significantly correlated with C_min on day 28 (p = 0.014), and the correlation remained significant after adjusting dasatinib dose (g), body weight (kg) (C_min/D/W) (p = 0.026). In the univariate analysis, deep molecular response, advanced PS, higher C_min/D/W were associated with a significantly higher risk of treatment alteration (HR 4.19, 95% CI: 1.06–16.60, p = 0.041; HR 5.26, 95% CI: 1.33–20.80, p = 0.018; and HR 10.15, 95% CI: 2.55–40.48, p = 0.001, respectively). In the multivariate analysis, advanced PS and higher C_min/D/W were correlated with the incidence of treatment alteration (HR 4.78, 95% CI: 1.01–22.70, p = 0.049; HR 6.17, 95% CI: 1.17–32.50, respectively).

Conclusion

Current data demonstrate that patients treated with dasatinib who displayed a high C_min/D/W value and/or advanced PS were at a high risk for altered treatment.

Excellent outcomes of 2G-TKI therapy after imatinib failure in chronic phase CML patients

Second-generation tyrosine kinase inhibitors (2G-TKIs) dasatinib and nilotinib produced historical rates of about 50% complete cytogenetic response (CCyR) and about 40% major molecular response (MMR) in chronic myeloid leukaemia (CML) patients failing imatinib. Direct comparisons between dasatinib and nilotinib are lacking, and few studies addressed the dynamics of deep molecular response (DMR) in a "real-life" setting. We retrospectively analyzed 163 patients receiving dasatinib (n = 95) or nilotinib (n = 68) as second-line therapy after imatinib. The two cohorts were comparable for disease's characteristics, although there was a higher rate of dasatinib use in imatinib-resistant and of nilotinib in intolerant patients. Overall, 75% patients not in CCyR and 60% patients not in MMR at 2G-TKI start attained this response. DMR was achieved by 61 patients (37.4%), with estimated rate of stable DMR at 5 years of 24%. After a median follow-up of 48 months, 60% of patients persisted on their second-line treatment. Rates and kinetics of cytogenetic and molecular responses, progression-free and overall survival were similar for dasatinib and nilotinib. In a "real-life" setting, dasatinib and nilotinib resulted equally effective and safe after imatinib failure, determining high rates of CCyR and MMR, and a significant chance of stable DMR, a prerequisite for treatment discontinuation.

Integrating Transcriptomic Data with Mechanistic Systems Pharmacology Models for Virtual Drug Combination Trials

Monotherapy clinical trials with mutation-targeted kinase inhibitors, despite some success in other cancers, have yet to impact glioblastoma (GBM). Besides insufficient blood-brain barrier penetration, combinations are key to overcoming obstacles such as intratumoral heterogeneity, adaptive resistance, and the epistatic nature of tumor genomics that cause mutation-targeted therapies to fail. With now hundreds of potential drugs, exploring the combination space clinically and preclinically is daunting. We are building a simulation-based approach that integrates patient-specific data with a mechanistic computational model of pan-cancer driver pathways (receptor tyrosine kinases, RAS/RAF/ERK, PI3K/AKT/mTOR, cell cycle, apoptosis, and DNA damage) to prioritize drug combinations by their simulated effects on tumor cell proliferation and death. Here we illustrate a first step, tailoring the model to 14 GBM patients from The Cancer Genome Atlas defined by an mRNA-seq transcriptome, and then simulating responses to three promiscuous FDA-approved kinase inhibitors (bosutinib, ibrutinib, and cabozantinib) with evidence for blood-brain barrier penetration. The model captures binding of the drug to primary targets and off-targets based on published affinity data and simulates responses of 100 heterogeneous tumor cells within a patient. Single drugs are marginally effective or even counterproductive. Common copy number alterations (PTEN loss, EGFR amplification, and NF1 loss) have a negligible correlation with single-drug or combination efficacy, reinforcing the importance of postgenetic approaches that account for kinase inhibitor promiscuity to match drugs to patients. Drug combinations tend to be either cytostatic or cytotoxic, but seldom both, highlighting the need for considering targeted and nontargeted therapy. Although we focus on GBM, the approach is generally applicable.

Pharmacology and pharmacokinetics of imatinib in pediatric patients

INTRODUCTION

The tyrosine kinase inhibitor (TKI) imatinib was rationally designed to target BCR-ABL1 which is constitutively activated in chronic myeloid leukemia (CML). Following the tremendous success in adults, imatinib also became licensed for treatment of CML in minors. The rarity of pediatric CML hampers the conduction of formal trials. Thus, imatinib is still the single TKI approved for CML treatment in childhood. Areas covered: This review attempts to provide an overview of the literature on pharmacology, pharmacokinetic, and pharmacogenetic of imatinib concerning pediatric CML treatment. Articles were identified through a PubMed search and by reviewing abstracts from relevant hematology congresses. Additional information was provided from the authors' libraries and expertise and from our own measurements of imatinib trough plasma levels in children. Pharmacokinetic variables (e.g. alpha 1-acid glycoprotein binding, drug-drug/food-drug interactions via cytochrome P450 3A4/5, cellular uptake mediated via OCT-1-influx variations and P-glycoprotein-mediated drug efflux) still await to be addressed in pediatric patients systematically. Expert commentary: TKI response rates vary among different individuals and pharmacokinetic variables all can influence CML treatment success. Adherence to imatinib intake may be the most prominent factor influencing treatment outcome in teenagers thus pointing towards the potential benefits of regular drug monitoring.

MNK1/2 inhibition limits oncogenicity and metastasis of KIT-mutant melanoma

Melanoma can be stratified into unique subtypes based on distinct pathologies. The acral/mucosal melanoma subtype is characterized by aberrant and constitutive activation of the proto-oncogene receptor tyrosine kinase C-KIT, which drives tumorigenesis. Treatment of these melanoma patients with C-KIT inhibitors has proven challenging, prompting us to investigate the downstream effectors of the C-KIT receptor. We determined that C-KIT stimulates MAP kinase-interacting serine/threonine kinases 1 and 2 (MNK1/2), which phosphorylate eukaryotic translation initiation factor 4E (eIF4E) and render it oncogenic. Depletion of MNK1/2 in melanoma cells with oncogenic C-KIT inhibited cell migration and mRNA translation of the transcriptional repressor SNAI1 and the cell cycle gene CCNE1. This suggested that blocking MNK1/2 activity may inhibit tumor progression, at least in part, by blocking translation initiation of mRNAs encoding cell migration proteins. Moreover, we developed an MNK1/2 inhibitor (SEL201), and found that SEL201-treated KIT-mutant melanoma cells had lower oncogenicity and reduced metastatic ability. Clinically, tumors from melanoma patients harboring KIT mutations displayed a marked increase in MNK1 and phospho-eIF4E. Thus, our studies indicate that blocking MNK1/2 exerts potent antimelanoma effects and support blocking MNK1/2 as a potential strategy to treat patients positive for KIT mutations.

Healthcare and economic burden of adverse events among patients with chronic myelogenous leukemia treated with BCR-ABL1 tyrosine kinase inhibitors

OBJECTIVES

BCR-ABL1 tyrosine kinase inhibitors (TKIs) are established treatments for chronic myelogenous leukemia (CML); however, they are associated with infrequent, but clinically serious adverse events (AEs). The objective of this analysis was to assess healthcare resource utilization and costs associated with AEs, previously identified using the FDA Adverse Event Reporting System (FAERS) in another study, among TKI-treated patients.

METHODS

Adult patients with ≥1 inpatient or ≥2 outpatient ICD-9-CM diagnosis codes for CML and ≥1 claim for a TKI treatment between January 1, 2006 and September 30, 2012 were identified from the Commercial and Medicare MarketScan databases. The first claim for a TKI was designated as the index event. Patients were required to have no TKI treatment during a 12-month baseline period. Healthcare resource utilization and costs associated with select AEs having the strongest association with TKI treatment (femoral arterial stenosis [FAS], peripheral arterial occlusive disease [PAOD], intermittent claudication, coronary artery stenosis [CAS], pericardial effusion, pleural effusion, malignant pleural effusion, conjunctival hemorrhage) were evaluated during a 12-month follow-up period.

RESULTS

The study sample included 2,005 CML patients receiving TKI therapy (mean age = 56 years; 56% male). Among all evaluated AEs, the highest mean inpatient healthcare costs were observed for FAS ($16,800 per patient) and PAOD ($14,263 per patient), which had total mean medical costs (inpatient + outpatient) of $17,015 and $15,154 per patient, respectively. Mean outpatient healthcare costs were highest for CAS ($1,861 per patient), followed by intermittent claudication ($947 per patient), PAOD ($891 per patient), and pleural effusion ($890 per patient). Total mean medical costs for fluid retention-related AEs, including pericardial effusion and pleural effusion, were $2,797 and $1,908 per patient, respectively.

CONCLUSIONS

The healthcare costs of AEs identified in the FAERS as having the strongest association with TKI treatment are substantial. Vascular stenosis-related AEs, including FAS and PAOD, have the highest cost burden.

Bosutinib induced pleural effusions: Case report and review of tyrosine kinase inhibitors induced pulmonary toxicity

Tyrosine kinase inhibitors are known to cause pulmonary complications. We report a case of bosutinib related bilateral pleural effusions in a patient with chronic myeloid leukemia. Characteristics of the pleural fluid are presented. We also discuss other tyrosine kinase inhibitors induced pulmonary toxicities, including pulmonary hypertension and interstitial lung disease.

Comparative analysis of pulmonary hypertension in patients treated with imatinib, nilotinib and dasatinib

Pulmonary hypertension (PH) is a rare, but life-threatening, adverse event in patients treated with tyrosine kinase inhibitors (TKIs), such as dasatinib, but has not been fully evaluated in patients treated with imatinib or nilotinib. We used echocardiography to noninvasively assess the incidence of PH in 105 patients with chronic myeloid leukaemia (CML) treated with imatinib (n = 37), nilotinib (n = 30) or dasatinib (n = 38). The mean triscupid regurgitation peak gradient (TRPG), which reflects pulmonary arterial pressure, was 22·7 mmHg in the imatinib group, 23·1 mmHg in the nilotinib group and 23·4 mmHg for dasatinib group. These values were not significantly different, but higher than those (19·0 mmHg) in newly diagnosed CML patients. A TRPG > 31 mmHg, marking possible PH onset, was detected in 9 of 105 patients: one (2·7%) treated with imatinib, three (10·0%) with nilotinib and five (13·2%) with dasatinib. Only three patients complained of dyspnoea, whereas the other six were asymptomatic. In addition, there was a tendency toward correlation of TRPG value and age or TKI treatment duration. These results suggested that treatment with not only dasatinib, but also imatinib and nilotinib, can be associated with subclinical PH. Noninvasive echocardiography is useful for screening, especially in older patients with long-term TKI treatment.

Axl Blockade by BGB324 Inhibits BCR-ABL Tyrosine Kinase Inhibitor-Sensitive and -Resistant Chronic Myeloid Leukemia

Purpose: BCR-ABL kinase inhibitors are employed successfully for chronic myeloid leukemia (CML) treatment. However, resistant disease and persistence of BCR-ABL1-independent leukemia stem and progenitor cells (LSPC) remain clinical challenges. The receptor tyrosine kinase Axl can mediate survival and therapy resistance of different cancer cells. We investigated the therapeutic potential of Axl inhibition in CML.Experimental Design: We used primary cells from patients with CML and TKI-sensitive and -resistant BCR-ABL1⁺ CML cell lines and a novel ponatinib-resistant cell line KCL-22 PonR. We analyzed the effects of genetic and pharmacologic Axl blockade by the small-molecule Axl inhibitor BGB324 in vitro and in vivo In BCR-ABL1-unmutated cells, we also investigated BGB324 in combination with imatinib.Results: We demonstrate overexpression of Axl receptor tyrosine kinase in primary cells of patients with CML compared with healthy individuals and a further increase of Axl expression in BCR-ABL TKI-resistant patients. We show that Axl blockage decreased growth of BCR-ABL TKI-sensitive CML cells including CD34⁺ cells and exerts additive effects with imatinib via inhibition of Stat5 activation. BGB324 also inhibits BCR-ABL TKI-resistant cells, including T315I-mutated and ponatinib-resistant primary cells. BGB324 exerted therapeutic effects in BCR-ABL1 T315I-mutated and ponatinib-resistant preclinical mouse models. Notably, BGB324 does not inhibit BCR-ABL1 and consequently inhibits CML independent of BCR-ABL1 mutational status.Conclusions: Our data show that Axl inhibition has therapeutic potential in BCR-ABL TKI-sensitive as well as -resistant CML and support the need for clinical trials. Clin Cancer Res; 23(9); 2289-300. ©2016 AACR.

Dasatinib for the treatment of chronic myeloid leukemia: patient selection and special considerations

Dasatinib is one of the second-generation tyrosine kinase inhibitors used in imatinib resistance and/or intolerance, as well as in the frontline setting in patients with chronic myeloid leukemia-chronic phase, and also in patients with advanced disease. It is also utilized in Philadelphia chromosome-positive acute lymphocytic leukemia. While choosing the appropriate tyrosine kinase inhibitor (ie, dasatinib) for each individual patient, comorbidities and BCR-ABL1 kinase domain mutations should always be taken into consideration, among other things. This review mainly focuses on patient selection prior to dasatinib administration in the treatment of chronic myeloid leukemia.

Pleural Effusion in Dasatinib-Treated Patients With Chronic Myeloid Leukemia in Chronic Phase: Identification and Management

Dasatinib has demonstrated durable clinical responses in patients, both as first-line and subsequent lines of therapy. Dasatinib use can result in pleural effusion in some patients, occurring any time during treatment and commonly characterized as mild to moderate in severity. Early identification of symptoms is essential in the proper management of pleural effusion. Prompt confirmation of diagnosis and management of pleural effusion can minimize morbidity and maximize the ability to preserve long-term clinical benefits with dasatinib. Here, we provide guidance on early identification and management of dasatinib-related pleural effusion.

Autophagy protects against dasatinib-induced hepatotoxicity via p38 signaling

Liver dysfunction is a common side effect associated with the treatment of dasatinib and its mechanism is poorly understood. Autophagy has been thought to be a potent survival or death factor for liver dysfunction, which may shed the light on a novel strategy for the intervention of hepatotoxicity caused by dasatinib. In this study, we show for the first time that autophagy is induced, which is consistent with the formation of liver damage. Autophagy inhibition exacerbated dasatinib-induced liver failure, suggesting that autophagy acted as a self-defense mechanism to promote survival. Oxidative stress has been shown to be an important stimulus for autophagy and hepatotoxicity. Interestingly, dasatinib increased the activity of p38, which is a critical modulator of the oxidative stress related to liver injury and autophagy. p38 silencing significantly blocked LC3-II induction and p62 reduction by dasatinib, which was accompanied by increased caspase-3 and PARP cleavage, indicating that autophagy alleviated dasatinib-induced hepatotoxicity via p38 signaling. Finally, the p38 agonist isoproterenol hydrochloride (ISO) alleviated dasatinib-induced liver failure by enhancing autophagy without affecting the anticancer activity of dasatinib. Thus, this study revealed that p38-activated autophagy promoted survival during liver injury, which may provide novel approaches for managing the clinical applications of dasatinib.

Chronic myeloid leukemia: Second-line drugs of choice

The efficacy of second-line treatment for chronic myeloid leukemia (CML) plays an important role in allowing CML patients to enjoy a normal life expectancy. Four tyrosine kinase inhibitors (TKIs) are presently available: bosutinib, dasatinib, nilotinib, ponatinib. Each one has different safety and activity profiles, which are reviewed here. No controlled studies are available to guide treatment decision, which must be based on the characterization of leukemic cells, especially in cases of resistance to TKI, coupled with the safety profile of each TKI. Patient comorbidities also play an important role in the treatment decision, which can achieve a new durable response in over 50% of treated patients.

Treatment Outcomes in CML Patients Treated With Tyrosine Kinase Inhibitors at a Tertiary Teaching Hospital in South Africa

BACKGROUND

Chronic myeloid leukemia (CML) has become one of the most treatable hematologic neoplasms since the advent of the tyrosine kinase inhibitors (TKIs), but it was not known if similar treatment outcomes could be achieved in a resource-limited country. We tested the hypothesis that, despite challenges to access to second-generation TKIs, excellent responses could be replicated in the setting of limited resources.

PATIENTS AND METHODS

Records of 58 patients with newly diagnosed CML in the chronic phase treated with TKIs at a tertiary teaching hospital in Cape Town, South Africa between 2003 and 2012 were reviewed and assessed according to European LeukemiaNet (ELN) criteria.

RESULTS

After a median follow-up of 60.5 months, progression-free survival at 60 and 96 months was 79.98% and 68.4%, respectively. Overall survival at 60 and 96 months was 92.9% and 83.6%, respectively. Progression to blast phase at 60 months was associated with poorer survival (P = .0002) but progression to accelerated phase was not (P = .1456). Attainment of a complete cytogenetic response at 12 months (P = .28) or major molecular response at 18 months (P = .268) did not have prognostic significance.

CONCLUSION

Despite delays in achievement of the target responses defined according to ELN criteria, the use of imatinib mesylate as a first-line treatment can still result in treatment outcomes comparable with those in developed countries. These data suggest opportunities for improvement and success might be even greater with uninterrupted access to second-generation or newer TKIs.

Relative survival in patients with chronic-phase chronic myeloid leukaemia in the tyrosine-kinase inhibitor era: analysis of patient data from six prospective clinical trials

BACKGROUND

Tyrosine-kinase inhibitors improve overall survival in patients with chronic myeloid leukaemia in chronic phase (CML-CP). Survival compared with the general population by age, response, and type of tyrosine-kinase inhibitor is not known. With use of data from trials of tyrosine kinase inhibitors, we compared overall survival in patients with newly diagnosed CML-CP to that of general population.

METHODS

In this cohort analysis, we included data from patients with CML-CP enrolled in six consecutive or parallel prospective clinical trials of tyrosine-kinase inhibitors at a single institution from July 30, 2000, to Sept 17, 2012. We analysed data for response and survival with the Kaplan-Meier method. For estimated overall survival in the general population, we obtained data from national vital statistics reports and matched to patients with CML-CP by age, sex, ethnicity, and year at diagnosis. We assessed numbers and causes of death within 1 year of beginning treatment by age group and by response to therapy. We then did univariate analysis and multivariate analysis to investigate factors associated with survival probability.

FINDINGS

Our analysis included 483 patients, 271 received imatinib, 105 received nilotinib, and 107 received dasatinib. Most patients were younger than 65 years, and no patients were older than 85 years. Median follow-up was 99·4 months (IQR 44·9-121·6), by which time 53 (11%) patients had died. The most common causes of death were progression to advanced disease stage, including complications of stem-cell transplantation (17 [4%] patients), secondary malignancies (nine [2%] patients), and cardiovascular causes (nine [2%] patients). 5-year overall survival in patients with CML-CP decreased in older age categories. For the whole population of patients with CML-CP, 5-year survival was only slightly lower than that of the matched general population (relative survival 94·7% [95% 92·1-97·4]). Individuals of all ages with a report of complete cytogenetic response to treatment or deeper within 1 year had a 5-year survival similar to that of the general population.

INTERPRETATION

In the era of treatment with tyrosine-kinase inhibitors, patients diagnosed with CML-CP can expect a 5-year survival that is only slightly lower than that of the general population. With access to tyrosine-kinase inhibitors, most patients with chronic myeloid leukaemia could enjoy a near normal life expectancy.

FUNDING

MD Anderson Cancer Center, National Cancer Institute.

Impact of imatinib interruption and duration of prior hydroxyurea on the treatment outcome in patients with chronic myeloid leukemia: Single institution experience

BACKGROUND

Optimal response requires that patients should be maintained on the drug continuously.

OBJECTIVES

To evaluate the influence of imatinib interruption and prior hydroxyurea use on the outcome of patients with chronic myeloid leukemia.

MATERIALS AND METHODS

Between January 2010 and November 2013, patients with chronic phase who received imatinib at the Kasr Al-ainy Center of Clinical Oncology were included.

RESULTS

Sixty patients were included in this study, thirty three patients (55%) received imatinib upfront, while 27 (45%) received imatinib post hydroxyurea. Imatinib was not given regularly in 50% of patients. In terms of response, only major molecular response and complete molecular response were statistically significant in favor of patients who were receiving imatinib regularly compared to those who had interruption (p<0.001, p<0.001, respectively) , while there was no difference in patients stratified according to prior hydroxyurea. The median progression free survival was 30.3 months (95% CI 24.3-36.3). Among the group of patients who received imatinib regularly, progression free survival was longer (p=0.049), there was no difference between those who received prior hydroxyurea versus those who did not (p=0.67).

CONCLUSION

Duration of prior hydroxyurea had no impact on response or progression free survival, while patients regular on imatinib had statistically significant difference with respect to major molecular response, complete molecular response and progression free survival compared to those who had periods of drug interruption, thus we need more governmental support to supply the drug without interruption to improve the outcome of therapy.

[Chronic myelogenous leukemia]

The advent of tyrosine kinase inhibitors (TKI) has improved the prognosis and outcome of patients with chronic myelogenous leukemia (CML) considerably. Compared with imatinib, the first-line use of second-generation inhibitors nilotinib and dasatinib has led to faster and deeper molecular remissions accompanied by a differential adverse effect profile. An essential part of the management of CML patients is the guideline-based application of cytogenetics and standardized polymerase chain reaction techniques to regularly assess the remission status. Long-lasting treatment-free remission in a minority of patients led to hopes for the curability of CML in a significant minority of patients. The use of interferon alpha combined with or after TKI therapy is associated with the induction of an immune response toward the leukemic clone. This innovative treatment approach is currently under prospective investigation to improve long-term response. The coordinated cooperation of academic and regional hospitals, office-based hematologists, laboratories, and patient representatives allows for up-to-date patient care and the early use of new therapeutic options in patients at risk.

Adverse drug reactions of imatinib in patients with chronic myeloid leukemia: A single-center surveillance study

Objective:

To monitor the adverse drug reactions (ADRs) associated with imatinib treatment in patients with chronic myeloid leukemia (CML) in a tertiary care hospital.

Materials and Methods:

The study was carried out by the Departments of Pharmacology and Medical Oncology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India. The study was carried out from March 2012 to February 2014. The ADRs were reported in a suspected Adverse Drug Reaction Reporting form, provided by the Central Drugs Standard Control Organization (CDSCO), Ministry of Health and Family Welfare, Government of India. The ADRs were analyzed for their pattern, causality and severity.

Results:

A total of 326 ADRs from 81 patients were reported during the study period. The hematological toxicities were much more prominent than the non-hematological toxicities in this study. The prevalence of thrombocytopenia (21.17%) was higher compared with other reactions. Further analysis showed that most of the ADRs were mild to moderate in nature. The causality assessment revealed that the majority of the ADRs belonged to the possible category.

Conclusion:

The present study in a tertiary care hospital suggests that hematological toxicities are predominant in CML patients treated with imatinib mesylate. The blood and lymphatic system (38.96%) was the most affected, with imatinib therapy and thrombocytopenia (21.17%) being the most commonly encountered ADRs in the present study. Thorough monitoring of ADRs is warranted for better treatment outcomes.

Safety and efficacy of imatinib in CML over a period of 10 years: data from the randomized CML-study IV

Tyrosine kinase inhibitors (TKI) have changed the natural course of chronic myeloid leukemia (CML). With the advent of second-generation TKI safety and efficacy issues have gained interest. The randomized CML - Study IV was used for a long-term evaluation of imatinib (IM). 1503 patients have received IM, 1379 IM monotherapy. After a median observation of 7.1 years, 965 patients (64%) still received IM. At 10 years, progression-free survival was 82%, overall survival 84%, 59% achieved MR(5), 72% MR(4.5), 81% MR(4), 89% major molecular remission and 92% MR(2) (molecular equivalent to complete cytogenetic remission). All response levels were reached faster with IM800 mg except MR(5). Eight-year probabilities of adverse drug reactions (ADR) were 76%, of grades 3-4 22%, of non-hematologic 73%, and of hematologic 28%. More ADR were observed with IM800 mg and IM400 mg plus interferon α (IFN). Most patients had their first ADR early with decreasing frequency later on. No new late toxicity was observed. ADR to IM are frequent, but mostly mild and manageable, also with IM 800 mg and IM 400 mg+IFN. The deep molecular response rates indicate that most patients are candidates for IM discontinuation. After 10 years, IM continues to be an excellent initial choice for most patients with CML.

Importance of adherence to BCR-ABL tyrosine-kinase inhibitors in the treatment of chronic myeloid leukemia

Treatment of chronic myeloid leukemia with BCR-ABL tyrosine kinase inhibitors requires full adherence in order to maximize the likelihood of achieving optimal responses, and to minimize healthcare costs. In this article, we review some of the methods available for assessing compliance, the main consequences of nonadherence on treatment outcomes, major factors commonly associated with poor compliance, a few successful measures for improving adherence and the most accepted recommendations for proactively managing adverse events.

Chronic myeloid leukemia patients who develop grade I/II pleural effusion under second-line dasatinib have better responses and outcomes than patients without pleural effusion

Dasatinib is a potent second generation TKI, and it is widely used in patients with CML, both in the up-front setting and failure after imatinib. Lymphocytosis in cases receiving dasatinib therapy has been shown to be associated with pleural effusion (PE) and better outcome. Although patients who gather lymphocytosis during dasatinib have superior responses, there is only little data about the correlation between PE, response rates, and survival. In order to answer this question, the aim of our study was to determine the frequency of PE and lymphocytosis among our CML patients receiving second-line dasatinib, and to compare the responses and outcomes between patients with or without PE. There were 18 patients (44%) who developed PE, in a total of 41 patients, with a median time of 15 months. Lymphocytosis was observed in nine patients (9/41, 22%) with a median duration of 6.5 months of dasatinib treatment. There were fourteen patients with at least one comorbidity that may play a role in the generation of PE. The cumulative MMR and CCyR rates were greater in PE+ patients (p<0.05). The PFS was significantly higher in PE+ group than PE- patients (p=0.013), also the OS was higher among PE+ patients than PE- group (p=0.042). In patients with a grade I/II PE, and durable responses under dasatinib, performing the management strategies for the recovery of effusion, together with continuing dasatinib can be a reasonable choice mainly in countries where third generation TKIs are not available. But alternative treatment strategies such as nilotinib or third generation TKIs can be chosen in patients with grade III/IV PE especially if the quality of life is severely affected.

Clinical pharmacokinetics of tyrosine kinase inhibitors: implications for therapeutic drug monitoring

The treatment of many malignancies has been improved in recent years by the introduction of molecular targeted therapies. These drugs interact preferentially with specific targets that are mutated and/or overexpressed in malignant cells. A group of such targets are the tyrosine kinases, against which a number of inhibitors (tyrosine kinase inhibitors, TKIs) have been developed. Imatinib, a TKI with targets that include the breakpoint cluster region-Abelson (bcr-abl) fusion protein kinase and mast/stem cell growth factor receptor kinase (c-Kit), was the first clinically successful drug of this type and revolutionized the treatment and prognosis of chronic myeloid leukemia and gastrointestinal stromal tumors. This success paved the way for the development of other TKIs for the treatment of a range of hematological malignancies and solid tumors. To date, 14 TKIs have been approved for clinical use and many more are under investigation. All these agents are given orally and are substrates of a range of drug transporters and metabolizing enzymes. In addition, some TKIs are capable of inhibiting their own transporters and metabolizing enzymes, making their disposition and metabolism at steady-state unpredictable. A given dose can therefore give rise to markedly different plasma concentrations in different patients, favoring the selection of resistant clones in the case of subtherapeutic exposure, and increasing the risk of toxicity if dosage is excessive. The aim of this review was to summarize current knowledge of the clinical pharmacokinetics and known adverse effects of the TKIs that are available for clinical use and to provide practical guidance on the implications of these data in patient management, in particular with respect to therapeutic drug monitoring.