Hepatotoxicity with vascular endothelial growth factor receptor tyrosine kinase inhibitors: A meta-analysis of randomized clinical trials

Immune-mediated hepatitis: Basic concepts and treatment

Immunotherapy with immune checkpoint inhibitors (ICIs) has revolutionized advanced cancer management. Nevertheless, the generalized use of these medications has led to an increase in the incidence of adverse immune-mediated events and the liver is one of the most frequently affected organs. Liver involvement associated with the administration of immunotherapy is known as immune-mediated hepatitis (IMH), whose incidence and clinical characteristics have been described by different authors. It often presents as mild elevations of amino transferase levels, seen in routine blood tests, that spontaneously return to normal, but it can also manifest as severe transaminitis, possibly leading to the permanent discontinuation of treatment. The aim of the following review was to describe the most up-to-date concepts regarding the epidemiology, diagnosis, risk factors, and progression of IMH, as well as its incidence in different types of common cancers, including hepatocellular carcinoma. Treatment recommendations according to the most current guidelines are also provided.

Modern developments in germline pharmacogenomics for oncology prescribing

The integration of genomic data into personalized treatment planning has revolutionized oncology care. Despite this, patients with cancer remain vulnerable to high rates of adverse drug events and medication inefficacy, affecting prognosis and quality of life. Pharmacogenomics is a field seeking to identify germline genetic variants that contribute to an individual's unique drug response. Although there is widespread integration of genomic information in oncology, somatic platforms, rather than germline biomarkers, have dominated the attention of cancer providers. Patients with cancer potentially stand to benefit from improved integration of both somatic and germline genomic information, especially because the latter may complement treatment planning by informing toxicity risk for drugs with treatment-limiting tolerabilities and narrow therapeutic indices. Although certain germline pharmacogenes, such as TPMT, UGT1A1, and DPYD, have been recognized for decades, recent attention has illuminated modern potential dosing implications for a whole new set of anticancer agents, including targeted therapies and antibody-drug conjugates, as well as the discovery of additional genetic variants and newly relevant pharmacogenes. Some of this information has risen to the level of directing clinical action, with US Food and Drug Administration label guidance and recommendations by international societies and governing bodies. This review is focused on key new pharmacogenomic evidence and oncology-specific dosing recommendations. Personalized oncology care through integrated pharmacogenomics represents a unique multidisciplinary collaboration between oncologists, laboratory science, bioinformatics, pharmacists, clinical pharmacologists, and genetic counselors, among others. The authors posit that expanded consideration of germline genetic information can further transform the safe and effective practice of oncology in 2022 and beyond.

A Rare Case of Hepatic Vanishing Bile Duct Syndrome Occurring after Combination Therapy with Nivolumab and Cabozantinib in a Patient with Renal Carcinoma

Tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs) significantly improve the outcomes of patients with advanced clear cell renal cell carcinoma (ccRCC); however, high-grade toxicities can occur, particularly during combination therapy. Herein, we report a patient with advanced metastatic ccRCC, who developed grade 4 cholestasis during combined therapy with nivolumab and cabozantinib. After the exclusion of common disorders associated with cholestasis and a failure of corticosteroids (CS), a liver biopsy was performed that demonstrated severe ductopenia. Consequently, a diagnosis of vanishing bile duct syndrome related to TKI and ICI administration was made, resulting in CS discontinuation and ursodeoxycholic acid administration. After a 7-month follow-up, liver tests had returned to normal values. Immunological studies revealed that our patient had developed robust T-cells and macrophages infiltrates in his lung metastasis, as well as in skin and liver tissues at the onset of toxicities. At the same time, peripheral blood immunophenotyping revealed significant changes in T-cell subsets, suggesting their potential role in the pathophysiology of the disease.

Target Therapy in Thyroid Cancer: Current Challenge in Clinical Use of Tyrosine Kinase Inhibitors and Management of Side Effects

Thyroid cancer (TC) is the most common endocrine malignancy. TC is classified as differentiated TC (DTC), which includes papillary and follicular subtypes and Hürthle cell variants, medullary TC (MTC), anaplastic TC (ATC), and poorly differentiated TC (PDTC). The standard of care in DTC consists of surgery together with radioactive iodine (¹³¹I) therapy and thyroid hormone, but patients with MTC do not benefit from ¹³¹I therapy. Patients with advanced TC resistant to ¹³¹I treatment (RAI-R) have no chance of cure, as well as patients affected by ATC and progressive MTC, in which conventional therapy plays only a palliative role, representing, until a few years ago, an urgent unmet need. In the last decade, a better understanding of molecular pathways involved in the tumorigenesis of specific histopathological subtypes of TC has led to develop tyrosine kinase inhibitors (TKIs). TKIs represent a valid treatment in progressive advanced disease and were tested in all subtypes of TC, highlighting the need to improve progression-free survival. However, treatments using these novel therapeutics are often accompanied by side effects that required optimal management to minimize their toxicities and thereby enable patients who show benefit to continue treatment and obtain maximal clinical efficacy. The goal of this overview is to provide an update on the current use of the main drugs recently studied for advanced TC and the management of the adverse events.

Pharmacology and pharmacovigilance of protein kinase inhibitors

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

Fatigue and its management in cancer patients undergoing VEGFR-TKI therapy

INTRODUCTION

Fatigue is the most common side effect of cancer and cancer treatment and is often called cancer fatigue or cancer-related fatigue. For cancer patients, cancer-related fatigue has a negative impact on participation in work and social activities, mood, and daily activities, significantly impairing quality of life. Vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGFR-TKIs) sometimes cause fatigue, and early detection and appropriate management of fatigue in cancer patients treated with a VEGFR-TKI prevent fatigue from becoming more severe, thus maximizing the benefits of the treatment.

AREAS COVERED

This paper focuses on fatigue and discusses its frequency, assessment, risk factors, and management methods.

EXPERT OPINION

The drugs currently available for treating cancer-related fatigue are not effective enough, and their mechanisms of action are not fully understood. Some agents have demonstrated efficacy as treatments for fatigue due to pharmacotherapy, and further elucidation of their mechanisms is expected, together with the development of new drugs. Since fatigue has a range of causes, its treatment requires not only medication, but also exercise, nutrition, and other therapeutic approaches. The successful treatment of fatigue will therefore need multidisciplinary therapy involving the establishment of systems of cooperation across various specialties.

Management of Apatinib-Related Adverse Events in Patients With Advanced Osteosarcoma From Four Prospective Trials: Chinese Sarcoma Study Group Experience

Four prospective trials have reported apatinib-related efficacy in osteosarcoma, with a high response rate of 43.2%. Currently, Adverse Events (AEs) have increasingly gained attention, as treatment with multiple tyrosine kinase inhibitors (TKIs) is potentially lifelong. For this reason, a consensus meeting of the Chinese Sarcoma Study Group (CSSG), which is a multidisciplinary panel composed of pediatric, medical and surgical oncologists specializing in sarcoma, nurse specialists, oncological senior pharmacists and gastroenterologists, was held to develop comprehensive guidelines on AEs emerging due to apatinib treatment to better assist in the prevention, management, and understanding of AE development. We summarized all AEs that arose in ≥10% of the participants as well as rare AEs that required extra caution to prevent that were observed in these four published prospective trials and arranged these AEs into 14 disorder systems according to CTCAE 5.0. In this review, we discuss strategies for the management of AEs in patients with advanced osteosarcoma, with the aim of maximizing treatment benefits and minimizing the need for apatinib treatment discontinuation. We also focus on providing recommendations for the prophylaxis and treatment of advanced osteosarcoma using apatinib to achieve optimal outcomes.

Comparison of Hepatotoxicity Associated With New BCR-ABL Tyrosine Kinase Inhibitors vs Imatinib Among Patients With Chronic Myeloid Leukemia: A Systematic Review and Meta-analysis

IMPORTANCE

Although BCR-ABL fusion oncoprotein tyrosine kinase inhibitors (BCR-ABL TKIs) can substantially improve the survival rate of chronic myeloid leukemia (CML), they are clinically accompanied by severe hepatotoxicity.

OBJECTIVE

To compare the relative risk (RR) of hepatotoxicity of new-generation BCR-ABL TKIs with that of imatinib, and to provide an overall assessment of the clinical benefit.

DATA SOURCES

PubMed, Embase, Cochrane library databases, and ClinicalTrials.gov were searched for clinical trials published between January 2000 and April 2020.

STUDY SELECTION

Study selection was conducted independently by 2 investigators according to the inclusion and exclusion criteria published previously in the protocol: only randomized phase 2 or phase 3 clinical trials that compared bosutinib, dasatinib, nilotinib, or ponatinib with imatinib were included. Among the 2666 records identified, 9 studies finally fulfilled the established criteria.

DATA EXTRACTION AND SYNTHESIS

Two investigators extracted study characteristics and data independently using a standardized data extraction form. Data were extracted according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines. When substantial heterogeneity was observed, pooled estimates were calculated based on the random-effect model; otherwise, the fixed-effect model was used.

MAIN OUTCOMES AND MEASURES

Data extracted included study characteristics, baseline patient information, interventions and data on all-grade and high-grade (grades 3 and 4) elevation of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, overall survival, and major molecular response (MMR). The RRs and 95% CIs were calculated using the inverse variance method.

RESULTS

Nine trials involving 3475 patients were analyzed; the median (range) age was 49 (18-91) years; 2059 (59.2%) were male patients. Increased risks were observed for each new-generation TKI except for dasatinib. Patients receiving new-generation TKIs were more likely to experience all grades of ALT elevation (pooled RR, 2.89; 95% CI, 1.78-4.69; P < .001) and grades 3 and 4 ALT elevation (pooled RR, 4.36; 95% CI, 2.00-9.50; P < .001) compared with those receiving imatinib. Patients receiving new-generation TKIs were also more likely to experience all grades of AST elevation (pooled RR, 2.20; 95% CI, 1.63-2.98; P < .001) and grades 3 and 4 AST elevation (pooled RR, 2.65; 95% CI, 1.59-4.42; P < .001) compared with those receiving imatinib. New-generation TKIs were associated with a significantly higher rate of MMR at 1 year compared with imatinib (pooled RR, 1.59; 95% CI, 1.44-1.75; P < .001). No statistical difference in overall survival at 1 year was found between new-generation TKIs and imatinib (pooled RR, 1.00; 95% CI, 1.00-1.01; P = .33).

CONCLUSIONS AND RELEVANCE

When compared to imatinib, bosutinib, nilotinib, and ponatinib had higher relative risks of hepatotoxicity. Treatment with new-generation TKIs was associated with a higher MMR rate at 1 year but not with 1-year overall survival.

Treatment of Hepatic Fibrosis in Mice Based on Targeted Plasmonic Hyperthermia

Liver fibrosis is a major health problem with multiple associated complications, which, to date, has no effective treatment. Hepatic stellate cells are the main responsible cells for fibrosis formation; upon their activation, excess accumulation of extracellular matrix and collagen deposits occurs. The mitogen platelet-derived growth factor (PDGF) and its receptor β (PDGFRβ) play a major role in hepatic stellate cells activation and are, therefore, promising targets for antifibrotic therapies. Gold nanorods hold great potential for diseased liver treatments, since their passive hepatic accumulation enhances active targeting strategies, hence increasing therapeutic efficiency. In addition, gold nanorods have photothermal properties that, combined with specific cell delivery, can be exploited to induce localized near-infrared light-mediated thermal ablation. Here, we demonstrate that gold nanorods coated with anti-PDGFRβ specifically target activated hepatic stellate cells in vivo. Additionally, gold nanorods-PDGFRβ-mediated photothermal therapy decreases fibrosis, hepatic inflammation, and hepatocyte injury in the experimental model of CCl₄-induced liver fibrosis in mice.

Lenvatinib and sorafenib for differentiated thyroid cancer after radioactive iodine: a systematic review and economic evaluation

BACKGROUND

Thyroid cancer is a rare cancer, accounting for only 1% of all malignancies in England and Wales. Differentiated thyroid cancer (DTC) accounts for ≈94% of all thyroid cancers. Patients with DTC often require treatment with radioactive iodine. Treatment for DTC that is refractory to radioactive iodine [radioactive iodine-refractory DTC (RR-DTC)] is often limited to best supportive care (BSC).

OBJECTIVES

We aimed to assess the clinical effectiveness and cost-effectiveness of lenvatinib (Lenvima®; Eisai Ltd, Hertfordshire, UK) and sorafenib (Nexar®; Bayer HealthCare, Leverkusen, Germany) for the treatment of patients with RR-DTC.

DATA SOURCES

EMBASE, MEDLINE, PubMed, The Cochrane Library and EconLit were searched (date range 1999 to 10 January 2017; searched on 10 January 2017). The bibliographies of retrieved citations were also examined.

REVIEW METHODS

We searched for randomised controlled trials (RCTs), systematic reviews, prospective observational studies and economic evaluations of lenvatinib or sorafenib. In the absence of relevant economic evaluations, we constructed a de novo economic model to compare the cost-effectiveness of lenvatinib and sorafenib with that of BSC.

RESULTS

Two RCTs were identified: SELECT (Study of [E7080] LEnvatinib in 131I-refractory differentiated Cancer of the Thyroid) and DECISION (StuDy of sorafEnib in loCally advanced or metastatIc patientS with radioactive Iodine-refractory thyrOid caNcer). Lenvatinib and sorafenib were both reported to improve median progression-free survival (PFS) compared with placebo: 18.3 months (lenvatinib) vs. 3.6 months (placebo) and 10.8 months (sorafenib) vs. 5.8 months (placebo). Patient crossover was high (≥ 75%) in both trials, confounding estimates of overall survival (OS). Using OS data adjusted for crossover, trial authors reported a statistically significant improvement in OS for patients treated with lenvatinib compared with those given placebo (SELECT) but not for patients treated with sorafenib compared with those given placebo (DECISION). Both lenvatinib and sorafenib increased the incidence of adverse events (AEs), and dose reductions were required (for > 60% of patients). The results from nine prospective observational studies and 13 systematic reviews of lenvatinib or sorafenib were broadly comparable to those from the RCTs. Health-related quality-of-life (HRQoL) data were collected only in DECISION. We considered the feasibility of comparing lenvatinib with sorafenib via an indirect comparison but concluded that this would not be appropriate because of differences in trial and participant characteristics, risk profiles of the participants in the placebo arms and because the proportional hazard assumption was violated for five of the six survival outcomes available from the trials. In the base-case economic analysis, using list prices only, the cost-effectiveness comparison of lenvatinib versus BSC yields an incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year (QALY) gained of £65,872, and the comparison of sorafenib versus BSC yields an ICER of £85,644 per QALY gained. The deterministic sensitivity analyses show that none of the variations lowered the base-case ICERs to < £50,000 per QALY gained.

LIMITATIONS

We consider that it is not possible to compare the clinical effectiveness or cost-effectiveness of lenvatinib and sorafenib.

CONCLUSIONS

Compared with placebo/BSC, treatment with lenvatinib or sorafenib results in an improvement in PFS, objective tumour response rate and possibly OS, but dose modifications were required to treat AEs. Both treatments exhibit estimated ICERs of > £50,000 per QALY gained. Further research should include examination of the effects of lenvatinib, sorafenib and BSC (including HRQoL) for both symptomatic and asymptomatic patients, and the positioning of treatments in the treatment pathway.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017055516.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Three case reports: Temporal association between tyrosine-kinase inhibitor-induced hepatitis and immune checkpoint inhibitors in renal cell carcinoma

RATIONALE

Hepatotoxicity is a well-known adverse effect of vascular endothelial growth factor receptor (VEGFR) tyrosine-kinase inhibitors (TKIs), usually employed for the treatment of metastatic renal cell carcinoma (mRCC). Immune checkpoint inhibitors (ICIs) have been shown to improve survival in specific patients with mRCC, but concerns have arisen over their safety profile, particularly as regards the risk of liver damage in those patients receiving TKIs sequentially or concurrently with these new drugs. Here, we report three cases of hepatitis presentation in patients receiving TKIs after ICIs that should potentially be considered in current clinical practice, where a combination of these hepatotoxic drugs is becoming increasingly used.

PATIENTS CONCERNS

All three patients were receiving TKIs therapy and presented with nonspecific clinical deterioration and liver enzyme elevation in different time frames according to the start of treatment. All were previously treated with ICIs.

DIAGNOSES

After performing imaging techniques and complementary laboratory tests for the differential diagnosis of hepatic injury, the diagnosis of potentially TKI-induced hepatitis was assumed in all these cases. Hepatic biopsy was performed only in the first case in order to confirm the diagnosis.

INTERVENTIONS

Potential toxic drugs were interrupted and steroids course with slow reduction regimen was administered in all these cases because of the previous use of ICIs.

OUTCOMES

The patients described improved with this conservative treatment without complications during the following weeks. Only one case presented a new episode of mild hepatic alteration while on treatment with following treatment.

LESSONS

Taking into account this new therapeutic context, stricter monitoring for potentially increased/altered adverse events should be indicated. Adequate patient selection and consideration of the safety profile of the different drugs used could help to optimize treatment in the near future.

[Imaging of medullary thyroid carcinoma]

BACKGROUND

About 10% of thyroid cancers are medullary thyroid carcinoma (MTC) and can occur sporadically, familially and in the context of type II multiple endocrine neoplasia (MEN). Imaging plays a pivotal role in screening family members and in diagnosis.

DIAGNOSTIC METHODS

Diagnosis is based on ultrasound (US), thyroid scintigraphy, serum calcitonin and carcinoembryonic antigen (CEA) as well as fine needle biopsy. High-resolution US is the most important imaging method for locoregional staging, combined with computed tomography (CT) of the mediastinum. Positron emission tomography (PET-CT) using 18-F-DOPA is particularly suited for suspected occult metastases in case of rising tumor markers in serum.

FINDINGS AND COURSE OF DISEASE

Diagnosis is made based on cytologic findings in a hypoechoic, cold thyroid nodule, combined with an elevation of serum calcitonin and CEA. US is the most important imaging modality during routine follow-up. CT is indicated for suspected mediastinal, lung, or liver metastases. CT should be replaced by MRI as early as possible to prevent significant cumulative radiation doses over time.

RECENT CLINICAL DEVELOPMENTS

Although MTC is curable by surgery only, owing to its radio- and chemoresistance, the disease will often progress only slowly, and even patients with metastases will frequently survive 10 years or longer. For more aggressive variants and late symptomatic stages, targeted drugs that have the potential to indicate stabilization or even a partial remission of the disease are under clinical investigation or already approved.

Role of Cytochrome P450 Enzymes in the Metabolic Activation of Tyrosine Kinase Inhibitors

Tyrosine kinase inhibitors are a rapidly expanding class of molecular targeted therapies for the treatment of various types of cancer and other diseases. An increasing number of clinically important small molecule tyrosine kinase inhibitors have been shown to undergo cytochrome P450-mediated bioactivation to form chemically reactive, potentially toxic products. Metabolic activation of tyrosine kinase inhibitors is proposed to contribute to the development of serious adverse reactions, including idiosyncratic hepatotoxicity. This article will review recent findings and ongoing studies to elucidate the link between drug metabolism and tyrosine kinase inhibitor-associated hepatotoxicity.

Mechanisms of mitochondrial toxicity of the kinase inhibitors ponatinib, regorafenib and sorafenib in human hepatic HepG2 cells

Previous studies have shown that certain kinase inhibitors are mitochondrial toxicants. In the current investigation, we determined the mechanisms of mitochondrial impairment by the kinase inhibitors ponatinib, regorafenib, and sorafenib in more detail. In HepG2 cells cultured in galactose and exposed for 24 h, all three kinase inhibitors investigated depleted the cellular ATP pools at lower concentrations than cytotoxicity occurred, compatible with mitochondrial toxicity. The kinase inhibitors impaired the activity of different complexes of the respiratory chain in HepG2 cells exposed to the toxicants for 24 h and in isolated mouse liver mitochondria exposed acutely. As a consequence, they increased mitochondrial production of ROS in HepG2 cells in a time- and concentration-dependent fashion and decreased the mitochondrial membrane potential concentration-dependently. In HepG2 cells exposed for 24 h, they induced mitochondrial fragmentation, lysosome content and mitophagy as well as mitochondrial release of cytochrome c, leading to apoptosis and/or necrosis. In conclusion, the kinase inhibitors ponatinib, regorafenib, and sorafenib impaired the function of the respiratory chain, which was associated with increased ROS production and a drop in the mitochondrial membrane potential. Despite activation of defense measures such as mitochondrial fission and mitophagy, some cells were liquidated concentration-dependently by apoptosis or necrosis. Mitochondrial dysfunction may represent a toxicological mechanism of hepatotoxicity associated with certain kinase inhibitors.

The Liver in Oncology

Gastroenterologists and hepatologists will encounter oncology patients who develop abnormal liver tests, patients with hepatic malignancies, and patients with acute and chronic liver disease who require chemotherapy or immediate evaluation. Chemotherapy can cause liver injury owing to toxic effects or idiosyncratic reactions. Immune checkpoint inhibitors may be associated with autoimmune-mediated liver toxicities. Venoocclusive disease requires immediate evaluation. Nodular regenerative hyperplasia is a chronic progressive disorder. Screening and prophylaxis for reactivation of hepatitis B is important to minimize complications in patients receiving chemotherapy. Patients with metastatic lesions can undergo resection or ablation. Hepatic injury may occur in those receiving radiation-based therapies.

PDGF signaling pathway in hepatic fibrosis pathogenesis and therapeutics (Review)

The platelet‑derived growth factor (PDFG) signaling pathway exerts persistent activation in response to a variety of stimuli and facilitates the progression of hepatic fibrosis. Since this pathway modulates a broad spectrum of cellular processes, including cell growth, differentiation, inflammation and carcinogenesis, it has emerged as a therapeutic target for hepatic fibrosis and liver‑associated disorders. The present review exhibits the current knowledge of the role of the PDGF signaling pathway and its pathological profiles in hepatic fibrosis, and assesses the potential of inhibitors which have been investigated in the experimental hepatic fibrosis model, in addition to the clinical challenges associated with these inhibitors.

Incidence and risk of regorafenib-induced hepatotoxicity

Regorafenib, an oral multi-kinase inhibitor, has been approved for the treatments of several malignancies. Unlike traditional cytotoxic chemotherapeutic agents, regorafenib therapy often induces a distinct profile of adverse events (AEs) including hepatotoxicity. Here we conducted an up-to-date meta-analysis to assess the incidence and risk of regorafenib related hepatic toxicities. PubMed and Embase database were reviewed from inception to June 2017 for relevant trials. Eligible studies include subjects with solid tumors treated with 160 mg of regorafenib daily during the first three week of each four-week cycle, and adequate safety data reporting the elevation of aspartate transaminase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and bilirubin. Statistical analyses were conducted to calculate the summary incidence and relative risk (RR). A total of 2,213 subjects from 14 trials were included. The incidences of regorafenib-associated all-grade and high-grade hepatotoxicity were: bilirubin elevation: 23% and 5%; AST elevation: 32% and 6%; ALT elevation: 27% and 5%; ALP elevation: 31% and 2%. Regorafenib-treated subjects had a significant increased risk of all-grade (RR = 3.10; 95% CI, 2.22–4.34) and high-grade (RR = 1.74; 95% CI, 1.09–2.80) bilirubin elevation; all-grade (RR = 1.51; 95% CI, 1.13–2.00) and high-grade (RR = 1.79; 95% CI, 1.00–3.22) AST elevation; all-grade (RR = 1.82; 95% CI, 1.25–2.64) and high-grade (RR = 3.07; 95% CI, 1.30–7.22) ALT elevation; and all-grade (RR = 2.11; 95% CI, 1.01–4.40) ALP elevation. Our results suggest that regorafenib is associated with an increased risk of hepatic toxicities. Hepatotoxicity examination at regular intervals should be advised to clinicians.

Hepatocellular Toxicity Associated with Tyrosine Kinase Inhibitors: Mitochondrial Damage and Inhibition of Glycolysis

Tyrosine kinase inhibitors (TKIs) are anticancer drugs with a lesser toxicity than classical chemotherapeutic agents but still with a narrow therapeutic window. While hepatotoxicity is known for most TKIs, underlying mechanisms remain mostly unclear. We therefore aimed at investigating mechanisms of hepatotoxicity for imatinib, sunitinib, lapatinib and erlotinib in vitro. We treated HepG2 cells, HepaRG cells and mouse liver mitochondria with TKIs (concentrations 1–100 μM) for different periods of time and assessed toxicity. In HepG2 cells maintained with glucose (favoring glycolysis), all TKIs showed a time- and concentration-dependent cytotoxicity and, except erlotinib, a drop in intracellular ATP. In the presence of galactose (favoring mitochondrial metabolism), imatinib, sunitinib and erlotinib showed a similar toxicity profile as for glucose whereas lapatinib was less toxic. For imatinib, lapatinib and sunitinib, cytotoxicity increased in HepaRG cells induced with rifampicin, suggesting formation of toxic metabolites. In contrast, erlotinib was more toxic in HepaRG cells under basal than CYP-induced conditions. Imatinib, sunitinib and lapatinib reduced the mitochondrial membrane potential in HepG2 cells and in mouse liver mitochondria. In HepG2 cells, these compounds increased reactive oxygen species production, impaired glycolysis, and induced apoptosis. In addition, imatinib and sunitinib impaired oxygen consumption and activities of complex I and III (only imatinib), and reduced the cellular GSH pool. In conclusion, imatinib and sunitinib are mitochondrial toxicants after acute and long-term exposure and inhibit glycolysis. Lapatinib affected mitochondria only weakly and inhibited glycolysis, whereas the cytotoxicity of erlotinib could not be explained by a mitochondrial mechanism.

Targeting Angiogenesis in Colorectal Cancer: Tyrosine Kinase Inhibitors

Colorectal cancer is commonly diagnosed throughout the world, and treatment options have greatly expanded over the last 2 decades. Targeting angiogenesis has been a major focus of study in a variety of malignancy types. Targeting angiogenesis has been achieved by several mechanisms in colorectal cancer, including use of antiangiogenic small molecule tyrosine kinase inhibitors (TKIs). There have been many attempts and failures to prove efficacy of TKIs in the treatment of colorectal cancer including sorafenib, sunitinib, vatalanib, and tivozanib. Regorafenib was the first TKI to demonstrate efficacy and is an orally active inhibitor of angiogenic (including the vascular endothelial growth factor receptors 1, 2, and 3), stromal, and oncogenic receptor tyrosine kinases. There are ongoing investigations of both regorafenib and ninetanib; however, there remains a critical need to better understand novel combinations with TKIs that could prove more efficacious than available options.

Effects of local irradiation combined with sunitinib on early remodeling, mitochondria, and oxidative stress in the rat heart

BACKGROUND AND PURPOSE

Thoracic (chemo)radiation therapy is increasingly administered with tyrosine kinase inhibitors (TKI). While TKI have adverse effects on the heart, it is unknown whether combination with other cancer therapies causes enhanced toxicity. We used an animal model to investigate whether radiation and sunitinib interact in their effects on the heart.

MATERIAL AND METHODS

Male Sprague-Dawley rats received local heart irradiation (9Gy per day, 5days). Oral sunitinib (8 or 15mg/kg bodyweight per day) started on day 1 of irradiation and continued for 2weeks. Cardiac function was examined with echocardiography. Cardiac remodeling, cell death, left ventricular (LV) oxidative stress markers, mitochondrial morphology and mitochondrial permeability transition pore (mPTP) opening were assessed.

RESULTS

Cardiac diameter, stroke volume, and LV volume, mass and anterior wall thickness increased in time, but only in the vehicle group. Sunitinib reduced LV inner diameter and volume in systole, which were counteracted by radiation. Sunitinib and radiation showed enhanced effects on mitochondrial morphology and mPTP opening, but not on cardiac troponin I, mast cell numbers or markers of oxidative stress.

CONCLUSIONS

This study found no early enhanced effects of radiation and sunitinib on cardiac function or structure. Long-term effects remain to be determined.

Increased risk of severe infections in cancer patients treated with vascular endothelial growth factor receptor tyrosine kinase inhibitors: a meta-analysis

Background

Vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGFR-TKIs) have been widely used in a variety of solid malignancies. Concerns have arisen regarding the risk of severe infections (≥grade 3) with use of these drugs, but the contribution of VEGFR-TKIs to infections is still unknown.

Methods

The databases of PubMed and abstracts presented at oncology conferences’ proceedings were searched for relevant studies from January 2000 to December 2014. Summary incidences, Peto odds ratio (Peto OR), and 95% confidence intervals (CIs) were calculated by using either random-effects or fixed-effects models according to the heterogeneity of included studies.

Results

A total of 16,488 patients from 27 randomized controlled trials were included. The risk of developing severe (Peto OR 1.69, 95% CI: 1.45–1.96, P<0.001) and fatal infections (Peto OR 1.78, 95% CI: 1.13–2.81, P=0.013) was significantly increased in patients treated with VEGFR-TKIs when compared to controls. Exploratory subgroup analysis showed no effect of tumor types, phase of trials, or agent used on the Peto OR of severe infections. When stratified according to specific infectious events, the risks of high-grade febrile neutropenia, pneumonia, fever, and sepsis were increased compared with controls, with Peto ORs of 1.57 (95% CI: 1.30–1.88, P<0.001), 1.79 (95% CI: 1.29–2.49, P<0.001), 5.35 (95% CI: 1.47–19.51, P=0.011), and 3.68 (95% CI: 1.51–8.99, P=0.004), respectively. Additionally, VEGFR-TKIs significantly increased the risk of fatal sepsis (OR 3.66, 95% CI: 1.47–9.13, P=0.005) but not fatal pneumonia (OR 1.34, 95% CI: 0.80–2.25, P=0.26).

Conclusion

The use of VEGFR-TKIs significantly increases the risk of developing severe and fatal infectious events in cancer patients. A close monitoring for any signs of infections is recommended for patients treated with VEGFR-TKIs.