Predicting toxicities for patients with advanced gastrointestinal stromal tumours treated with imatinib: A study of the European Organisation for Research and Treatment of Cancer, the Italian Sarcoma Group, and the Australasian Gastro-Intestinal Trials Group (EORTC–ISG–AGITG)

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.

Biological screening of a unique drug library targeting MRGPRX2

Background

Allergic drug reaction or drug allergy is an immunologically mediated drug hypersensitivity reaction (DHR). G-protein coupled receptors (GPCRs) are common drug targets and communicate extracellular signals that initiate cellular responses. Recent evidence shows that GPCR MRGPRX2 is of major importance in IgE-independent pseudo-allergic DHRs based on the suspected interactions between many FDA-approved peptidergic compounds and MRGPRX2.

Objective

Our aim was to uncover novel MRGPRX2-selective and -potent agonists as drug candidates responsible for clinical features of pseudo-allergic DHRs.

Methods

We conducted a primary high-throughput screening (HTS), coupled with mutagenesis targeting the MRGPRX2 N62S mutation, on a panel of 3,456 library compounds. We discovered pharmacologically active hit compounds as agonists of the MRGPRX2 protein according to high degrees of potency evaluated by the calcium response and validated by the degranulation assay. Using the molecular tool Forge, we also characterized the structure-activity relationship shared by identified hit compounds.

Results

The alternative allele of single nucleotide polymorphism rs10833049 (N62S) in MRGPRX2 demonstrated loss-of-function property in response to substance P and antineoplastic agent daunorubicin hydrochloride. We applied a unique assay system targeting the N62S mutation to the HTS and identified 84 MRGPRX2-selective active hit compounds representing diverse classes according to primary drug indications. The top five highly represented groups included fluoroquinolone and non-fluoroquinolone antibiotics; antidepressive/antipsychotic; antihistaminic and antineoplastic agents. We classified hit compounds into 14 clusters representing a variety of chemical and drug classes beyond those reported, such as opioids, neuromuscular blocking agents, and fluoroquinolones. We further demonstrated MRGPRX2-dependent degranulation in the human mast cell line LAD2 cells induced by three novel agonists representing the non-fluoroquinolone antibiotics (bacitracin A), anti-allergic agents (brompheniramine maleate) and tyrosine-kinase inhibitors (imatinib mesylate).

Conclusion

Our findings could facilitate the development of interventions for personalized prevention and treatment of DHRs, as well as future pharmacogenetic investigations of MRGPRX2 in relevant disease cohorts.

Health-Related Quality of Life and Side Effects in Gastrointestinal Stromal Tumor (GIST) Patients Treated with Tyrosine Kinase Inhibitors: A Systematic Review of the Literature

BACKGROUND

The introduction of tyrosine kinase inhibitors (TKIs) has revolutionized the treatment of gastrointestinal stromal tumors (GISTs), resulting in a substantial gain in median overall survival. Subsequently, health-related quality of life (HRQoL) has become more relevant. Here, we systematically review the available literature on HRQoL issues and side effects of different TKIs registered for the treatment of GIST.

METHODS

A search through five databases was performed. Full reports in English describing HRQoL outcomes and/or side effects in GIST patients on TKI therapy were included.

RESULTS

A total of 104 papers were included; 13 studies addressed HRQoL, and 96 studies investigated adverse events. HRQoL in patients treated with imatinib, regorafenib, and ripretinib remained stable, whereas most sunitinib-treated patients reported a decrease in HRQoL. Severe fatigue and fear of recurrence or progression were specifically assessed as HRQoL issues and had a negative impact on overall HRQoL as well as psychological and physical well-being. The majority of studies focused on physician-reported side effects. Nearly all GIST patients treated with a TKI experienced at least one adverse event, mostly mild to moderate.

CONCLUSIONS

Despite the fact that almost all patients treated with a TKI experienced side effects, this did not seem to affect overall HRQoL during TKI therapy. In daily practice, it are the side effects that hamper a patient's HRQoL resulting in treatment adjustments, suggesting that the reported side effects were underestimated by physicians, or the measures used to assess HRQoL do not capture all relevant issues that determine a GIST patient's HRQoL.

An evaluation of masitinib for treating systemic mastocytosis

Introduction: Systemic Mastocytosis (SM) is a complex family of rare diseases, against which pharmacological therapies are still very few. It is a c-kit driven disease, whose disregulation leads to uncontrolled activation and proliferation of mast cells (MCs) with consequent release of effector molecules which are responsible for its clinical manifestations. Areas covered: Masitinib is a relatively new potential drug against SM and its chemical structure strictly derives from imatinib, the first tyrosine kinase inhibitor which entered the pharmaceutical market about 15 years ago. In this review, the authors present masitinib in all its properties, from chemistry to pharmacology and toxicity to its potential clinical application in SM, focusing the discussion on the few clinical trials in which it has been involved, with a particular attention on the still open challenge to determine how to measure the response to therapy. Expert opinion: In spite of their similarity in chemistry and biological activity against submolecular targets, masitinib is much more selective towards c-kit receptors than other tyrosine kinases, such as Bcl-Abl. Furthermore, its ability to inhibit degranulation, cytokine production and MCs migration from bone marrow gives it a great chance to become an important therapeutic option for selected SM patients.

Genetic polymorphisms in ABCG2 and CYP1A2 are associated with imatinib dose reduction in patients treated for gastrointestinal stromal tumors

Imatinib has a mild toxicity profile, although severe adverse events may develop. In this pharmacogenetic pathway analysis the need for dose reduction and cessation of therapy was tested for an association with single nucleotide polymorphisms (SNPs) in genes related to imatinib pharmacology. Retrospective data from 315 patients with a gastrointestinal stromal tumor who received imatinib 400 mg o.d. was associated with 36 SNPs. SNPs that showed a trend in univariate testing were tested in a multivariate model with clinical factors and correction for multiple testing was performed. Dose reduction was associated with carriership of the A-allele in rs2231137 in ABCG2 (OR 7.35, p = 0.0002) and two C-alleles in rs762551 in CYP1A2 (OR 7.12, p = 0.001). Results remained significant after correction for multiple testing. Therapy cessation did not show an association with any of the tested SNPs. These results may help identifying patients at increased risk for toxicity who could benefit from intensified follow-up.

Molecularly Targeted Therapy and Radiotherapy in the Management of Localized Gastrointestinal Stromal Tumor (GIST) of the Rectum: A Case Report

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. The main treatment for localized gastrointestinal stromal tumors is surgical resection. These tumors respond poorly to conventional cytotoxic chemotherapy agents and to radiotherapy. Imatinib mesylate, a small-molecule kinase inhibitor, has proved useful in the treatment of recurrent or metastatic GISTs and is now being tested in the adjuvant and neoadjuvant setting. The role of radiotherapy in the management of patients with GIST is currently restricted to symptomatic palliation.

We present the case of a 54-year-old man affected by rectal GIST extending to the anal canal, with constipation, hematochezia, and anal pain. He received imatinib, 400 mg orally per day, for a week before and during radiation therapy. Irradiation was delivered to the gross tumor volume by 3D conformal therapy. The planned total dose was 50.4 Gy in fractions of 1.8 Gy daily. We observed a partial clinical response 3 weeks after the end of combination treatment. The patient then underwent a sphincter-saving surgical procedure. There was no perioperative morbidity and a complete pathological response was obtained.

At the present time, the role of radiotherapy in the management of patients with GIST is restricted to symptomatic palliation. The introduction of molecularly targeted therapy combined with radiation therapy could improve the outcomes for patients diagnosed with GIST.

Gastrointestinal Stromal Tumors (GISTs): From Science to Targeted Therapy

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. GISTs represent a distinct category of tumors characterized by oncogenic mutations of the KIT receptor tyrosine kinase in a majority of patients. KIT is useful not only for the diagnosis but also for targeted therapy of this disease. Imatinib, a tyrosine kinase inhibitor, is widely used in advanced and metastatic GISTs. This agent revolutionized the treatment strategy of advanced disease and is being tested in the neoadjuvant and adjuvant settings with encouraging results. New therapeutic agents like sunitinib have now been approved, enriching the treatment scenario for imatinib-resistant GISTs. The present review reports on the peculiar characteristics of this disease through its biology and molecular patterns, focusing on the predictive value of KIT mutations and their correlation with clinical outcome as well as on the activity of and resistance to approved targeted drugs.

Molecular and Clinical Approach to Intra-abdominal Adverse Effects of Targeted Cancer Therapies

Targeted cancer therapies encompass an exponentially growing number of agents that involve a myriad of molecular pathways. To excel within this rapidly changing field of clinical oncology, radiologists must eschew traditional organ system-based approaches of cataloging adverse effects in favor of a conceptual framework that incorporates molecular mechanisms and associated clinical outcomes. Understanding molecular mechanisms that underlie imaging manifestations of adverse effects and known associations with treatment response allows radiologists to more effectively recognize adverse effects and differentiate them from tumor progression. Radiologists can therefore more effectively guide oncologists in the management of adverse effects and treatment decisions regarding continuation or cessation of drug therapy. Adverse effects from targeted cancer therapies can be classified into four categories: (a) category 1, on-target adverse effects associated with treatment response; (b) category 2, on-target adverse effects without associated treatment response; (c) category 3, off-target adverse effects; and (d) category 4, tumor necrosis-related adverse effects. This review focuses on adverse effects primarily within the abdomen and pelvis classified according to established or hypothesized molecular mechanisms and illustrated with images of classic examples and several potential emerging toxic effects. ^©RSNA, 2017.

Unravelling the pharmacologic opportunities and future directions for targeted therapies in gastro-intestinal cancers part 2: Neuroendocrine tumours, hepatocellular carcinoma, and gastro-intestinal stromal tumours

Until the 1990s, cytotoxic chemotherapy has been the cornerstone of medical therapy for gastrointestinal (GI) cancers. Better understanding of the cancer cell molecular biology has led to the therapeutic revolution of targeted therapies, i.e. monoclonal antibodies or small molecule inhibitors directed against proteins that are specifically overexpressed or mutated in cancer cells. These agents, being more specific to cancer cells, were expected to be less toxic than conventional cytotoxic agents. However, their effects have sometimes been disappointing, due to intrinsic or acquired resistance mechanisms, or to an activity restricted to some tumour settings, illustrating the importance of patient selection and early identification of predictive biomarkers of response to these therapies. Targeted agents have provided clinical benefit in many GI cancer types. Particularly, some GI tumours are considered chemoresistant and targeted therapies have offered a new therapeutic base for their management. Hence, somatostatin receptor-directed strategies, sorafenib, and imatinib have revolutioned the management of neuroendocrine tumours (NET), hepatocellular carcinoma (HCC), and gastrointestinal stromal tumours (GIST), respectively, and are now used as first-line treatment in many patients affected by these tumours. However, these agents face problems of resistances and identification of predictive biomarkers from imaging and/or biology. We propose a comprehensive two-part review providing a panoramic approach of the successes and failures of targeted agents in GI cancers to unravel the pharmacologic opportunities and future directions for these agents in GI oncology. In this second part, we will focus on NET, HCC, and GIST, whose treatment relies primarily on targeted therapies.

Sab mediates mitochondrial dysfunction involved in imatinib mesylate-induced cardiotoxicity

Imatinib mesylate is an effective treatment for chronic myelogenous leukemia and gastrointestinal stromal tumors. Although imatinib mesylate is highly tolerable, it has been implicated in severe congestive heart failure in mouse models and patients. A hallmark of imatinib mesylate-induced cardiotoxicity is mitochondrial dysfunction. The mitochondrial scaffold Sab has been implicated in facilitating signaling responsible for mitochondrial dysfunction in a c-Jun N-terminal Kinase (JNK)-dependent manner. We examined the impact of Sab-mediated signaling on imatinib mesylate cardiotoxicity in H9c2 rat cardiomyocyte-like cells. Silencing Sab increased the LD₅₀ of imatinib mesylate 4-fold in H9c2 cells. Disrupting Sab-mediated signaling prevented imatinib mesylate-induced apoptosis as well. Knockdown of Sab or inhibition with a small peptide prevented oxidative stress, which was indicated by decreased reactive oxygen species production, lipid peroxidation, and protein carbonylation. Further, inhibition of Sab-related signaling partially rescued deficits in mitochondrial respiration, ATP production, and membrane potential in imatinib mesylate-treated H9c2 cells. Conversely, over-expression of Sab in H9c2 cells increased the cardiotoxicity of imatinib mesylate in vitro decreasing the LD₅₀ over 4-fold. Sab expression was induced in H9c2 cells following cardiovascular-like stress in an AP-1 dependent manner. These data demonstrate that imatinib mesylate influences mitochondrial signaling leading to mitochondrial dysfunction and cardiotoxicity.

Platelet-derived growth factor receptor/platelet-derived growth factor (PDGFR/PDGF) system is a prognostic and treatment response biomarker with multifarious therapeutic targets in cancers

Progress in cancer biology has led to an increasing discovery of oncogenic alterations of the platelet-derived growth factor receptors (PDGFRs) in cancers. In addition, their overexpression in numerous cancers invariably makes PDGFRs and platelet-derived growth factors (PDGFs) prognostic and treatment markers in some cancers. The oncologic alterations of the PDGFR/PDGF system affect the extracellular, transmembrane and tyrosine kinase domains as well as the juxtamembrane segment of the receptor. The receptor is also involved in fusions with intracellular proteins and receptor tyrosine kinase. These discoveries undoubtedly make the system an attractive oncologic therapeutic target. This review covers elementary biology of PDGFR/PDGF system and its role as a prognostic and treatment marker in cancers. In addition, the multifarious therapeutic targets of PDGFR/PDGF system are discussed. Great potential exists in the role of PDGFR/PDGF system as a prognostic and treatment marker and for further exploration of its multifarious therapeutic targets in safe and efficacious management of cancer treatments.

Managing Cutaneous Side Effects From Targeted Molecular Inhibitors for Melanoma and Nonmelanoma Skin Cancer

BACKGROUND

Targeted anticancer therapies can cause cutaneous adverse events different from classical chemotherapeutic toxicities.

OBJECTIVE

To review the literature on dermatologic adverse events (DAEs) of targeted molecular inhibitors for melanoma and nonmelanoma skin cancers with a focus on management options.

MATERIALS AND METHODS

A comprehensive literature search related to the side effects and management of these side effects from vemurafenib, dabrafenib, trametinib (BRAF inhibitors), pembrolizumab (antiprogrammed-death-receptor-1 antibody), imatinib (tyrosine kinase inhibitor), ipilimumab (anticytotoxic T-lymphocyte antigen-4 antibody), cetuximab (epidermal growth factor receptor inhibitor), sorafenib (multikinase inhibitor), and vismodegib (smoothened receptor inhibitor).

RESULTS

No large controlled studies specifically examining the management of DAEs of targeted molecular inhibitors exist, although there are case report-based recommendations and algorithms developed by expert panels to manage these adverse events.

CONCLUSION

Many options for managing the cutaneous side effects of targeted molecular inhibitors are similar to those used in general dermatology practice. When used effectively, drug dosing and patient quality of life may be optimized.

Kinase inhibitors and monoclonal antibodies in oncology: clinical implications

Molecularly targeted cancer therapies, such as small-molecule kinase inhibitors and monoclonal antibodies, constitute a rapidly growing and an important part of the oncology armamentarium. Unlike conventional (cytotoxic) chemotherapeutics, targeted therapies were designed to disrupt cancer cell pathogenesis at specific biological points essential for the development and progression of the tumour. These agents were developed to disrupt specific targets with the aim of minimizing treatment burden compared with conventional chemotherapy. Nevertheless the increasingly common use of targeted therapies has revealed some unanticipated, often clinically significant toxic effects, as well as compromising effective palliative and end-of-life management approaches. Although patients and clinicians welcome improvements in cancer prognosis, these changes can also impact patient quality-of-life. Therefore, as demand for oncology expertise increases, physicians need to apprise themselves of targeted therapies and their clinical implications, including drug-specific side effects, impact on quality of life, and cost issues, especially in relation to end-of-life care. This Review provides a useful summary and guide for professionals treating patients with malignant diseases.

Current status of publicly available sarcoma cell lines for use in proteomic studies

Cell lines are valuable resources for proteomic studies and can be used as tools to verify the significance of proteomic findings. Here, the authors overview the current status of the publicly available sarcoma cell lines. The authors surveyed seven major cell banks and found that the diversity observed in the sarcoma cell banks was largely insufficient; sarcoma cell lines are available for only a limited histological subtype. They also observed a number of issues with the pathological diagnosis of the cell lines, limitations in their behavioral diversity, and various unmet needs. Well characterized cell lines with accurate diagnosis based on modern diagnosis criteria should be available from public cell banks. The authors conclude that additional cell lines, along with detailed genetic and pathological analyses, should be prepared and deposited in order to promote sarcoma-specific proteomic research. The authors focused on sarcoma cell lines, but their discussion can be applied to the other cancers.

Imatinib-induced agranulocytosis in patients with gastrointestinal stromal tumors

Agranulocytosis is a rare but serious side effect of imatinib in gastrointestinal stromal tumor (GIST) patients. Imatinib is an inhibitor of the proto-oncogene tyrosine kinase (c-kit) and the first-line agent in patients with locally advanced and metastatic GIST. Little evidence is available on the management of this adverse event, and consensus-based guidelines are lacking. In this article, we describe 4 patients with agranulocytosis after starting imatinib. In addition, an overview of the available literature concerning the underlying mechanisms is given, and therapeutic strategies for overcoming this adverse event are discussed. In our experience it appears safe to restart imatinib after normalization of neutrophil count. In case of relapse of agranulocytosis, reintroduction combined with prednisolone, with treatment with granulocyte colony-stimulating factor or dose reduction can be considered.

Fluid retention associated with imatinib treatment in patients with gastrointestinal stromal tumor: quantitative radiologic assessment and implications for management

Objective

We aimed to describe radiologic signs and time-course of imatinib-associated fluid retention (FR) in patients with gastrointestinal stromal tumor (GIST), and its implications for management.

Materials and Methods

In this Institutional Review Board-approved, retrospective study of 403 patients with GIST treated with imatinib, 15 patients with imaging findings of FR were identified by screening radiology reports, followed by manual confirmation. Subcutaneous edema, ascites, pleural effusion, and pericardial effusion were graded on a four-point scale on CT scans; total score was the sum of these four scores.

Results

The most common radiologic sign of FR was subcutaneous edema (15/15, 100%), followed by ascites (12/15, 80%), pleural effusion (11/15, 73%), and pericardial effusion (6/15, 40%) at the time of maximum FR. Two distinct types of FR were observed: 1) acute/progressive FR, characterized by acute aggravation of FR and rapid improvement after management, 2) intermittent/steady FR, characterized by occasional or persistent mild FR. Acute/progressive FR always occurred early after drug initiation/dose escalation (median 1.9 month, range 0.3-4.0 months), while intermittent/steady FR occurred at any time. Compared to intermittent/steady FR, acute/progressive FR was severe (median score, 5 vs. 2.5, p = 0.002), and often required drug-cessation/dose-reduction.

Conclusion

Two distinct types (acute/progressive and intermittent/steady FR) of imatinib-associated FR are observed and each type requires different management.

Iodine-125 induces apoptosis via regulating p53, microvessel density, and vascular endothelial growth factor in colorectal cancer

Background

Iodine interstitial brachytherapy has been widely reported for treating colorectal cancer (CRC). However, the inhibitory molecular mechanism of iodine-125 (I-125) on CRC has not been reported.

Methods

To illustrate the inhibitory mechanism of iodine-125 (I-125) on CRC, we established the animal models of CRC via the injection of HCT-8 cells into nude mice. Subsequently, the I-125 granules were implanted into the tumor of the animal model at different dosages. Proliferating cell nuclear antigen and terminal transferase dUTP nick end labeling were used to detect the apoptosis of the tumor cells. Immunohistochemistry SP staining was used to measure the expression of p53 protein. The protein levels were examined with western blot and ELISA. Meanwhile, microvessel density (MVD) was counted by endothelial cells immunostained by anti-CD34 antibody.

Results

The results showed that I-125 protests against CRC via increasing the protein level of p53 and decreasing the level of vascular endothelial growth factor (VEGF), leading to the decrease of MVD in CRC (P <0.0001). An effective inhibition dosage of I-125 ranged from 0.4 to 0.8 mCi.

Conclusions

The inhibitory mechanisms of iodine on CRC acted through an increase in the level of p53 and a decrease in the level of VEGF, resulting in a decrease of MVD.

A trivalent approach for determining in vitro toxicology: Examination of oxime K027

Unforeseen toxic effects contribute to compound attrition during preclinical evaluation and clinical trials. Consequently, there is a need to correlate in vitro toxicity to in vivo and clinical outcomes quickly and effectively. We propose an expedited evaluation of physiological parameters in vitro that will improve the ability to predict in vivo toxicity of potential therapeutics. By monitoring metabolism, mitochondrial physiology and cell viability, our approach provides insight to the extent of drug toxicity in vitro. To implement our approach, we used human hepatocellular carcinoma cells (HepG2) and neuroblastoma cells (SH-SY5Y) to monitor hepato- and neurotoxicity of the experimental oxime K027. We utilized a trivalent approach to measure metabolism, mitochondrial stress and induction of apoptosis in 96-well formats. Any change in these three areas may suggest drug-induced toxicity in vivo. K027 and pralidoxime, an oxime currently in clinical use, had no effect on glycolysis or oxygen consumption in HepG2 and SH-SY5Y cells. Similarly, these oximes did not induce oxidant generation nor alter mitochondrial membrane potential. Further, K027 and pralidoxime failed to activate effector caspases, and these oximes did not alter viability. The chemotherapeutic agent, docetaxel, negatively affected metabolism, mitochondrial physiology and viability. Our studies present a streamlined high-throughput trivalent approach for predicting toxicity in vitro, and this approach reveals that K027 has no measurable hepatotoxicity or neurotoxicity in vitro, which correlates with their in vivo data. This approach could eliminate toxic drugs from consideration for in vivo preclinical evaluation faster than existing toxicity prediction panels and ultimately prevent unnecessary experimentation.

Clinical efficacy and safety of imatinib in the management of Ph(+) chronic myeloid or acute lymphoblastic leukemia in Chinese patients

Imatinib mesylate is considered the standard first-line systemic treatment for patients with chronic myeloid leukemia (CML) and functions by targeting BCR-ABL tyrosine kinases. Imatinib has substantially changed the clinical management and improved the prognosis of CML and Philadelphia chromosome-positive acute lymphocytic leukemia (Ph⁺ ALL). Here, we review the pharmacology, mode of action, and pharmacokinetics of imatinib; Chinese efficacy studies in CML and Ph⁺ ALL; safety and tolerability; patient-focused perspectives, such as quality of life, patient satisfaction, acceptability, and adherence; and uptake of imatinib.

Systematic review of the side effects associated with tyrosine kinase inhibitors used in the treatment of gastrointestinal stromal tumours on behalf of the EORTC Quality of Life Group

Tyrosine kinase inhibitors (TKIs) have revolutionised the treatment of advanced gastrointestinal stromal tumours (GISTs). Imatinib is approved as first line therapy and sunitinib is used in cases of imatinib resistance or intolerance. Compared with conventional treatments, TKIs are delivered over longer periods of time and are more specific in their targets (i.e., molecularly targeted), thus presenting different side effect profiles. We review the safety profiles of imatinib and sunitinib, documenting a total of 95 side effects including patient based as well as medically defined outcomes. Gastrointestinal complaints, particularly diarrhoea and nausea, oedema, fatigue and haematological disorders, notably anaemia, are amongst the most prevalent side effects. While there is overlap between the side effect profiles of imatinib and sunitinib, important differences emerge in the frequencies of oedema, hypertension, thyroid functioning, muscle and joint pains, as well as skin and oral conditions. Awareness of potential side effects is informative to both clinician and patient in terms of treatment decision making and can have important implications for treatment adherence and clinical outcome.

Metastasectomy for gastrointestinal stromal tumors

Gastrointestinal stromal tumor (GIST) is the most common sarcoma of the intestinal tract. Improvements in understanding the molecular pathogenesis of GIST have resulted in novel treatment strategies combining surgery with tyrosine kinase inhibitors (TKIs). Metastasectomy in carefully selected patients who have stable or responsive disease on imatinib should be considered in the multidisciplinary setting. We review existing data on surgical cytoreduction in metastatic GIST while on targeted therapy and compare outcomes with either treatment alone.

Molecular targeted therapies in non-GIST soft tissue sarcomas: what the radiologist needs to know

Non-gastrointestinal stromal soft tissue sarcomas are uncommon neoplasms that have a dismal prognosis due to a high incidence of metastases and a poor response to conventional chemotherapy. The identification of characteristic genetic alterations in several of these tumors has opened the window for molecular targeted therapies in patients who have failed conventional chemotherapy. Imaging plays a critical role in assessing the response to these novel therapeutic agents. Just like the response of gastrointestinal stromal tumors to imatinib, the response of non-gastrointestinal stromal soft tissue sarcomas to molecular targeted drugs is better evaluated on imaging by alternate tumor response criteria such as the Choi criteria. In addition, these drugs are associated with distinct class-specific drug toxicities that can come to attention for the first time on imaging. The purpose of this article is to provide a primer for the radiologist on the various molecular targeted therapies in advanced/metastatic non-gastrointestinal stromal soft tissue sarcomas with emphasis on the role of imaging in assessing treatment response and complications.

Optimized dose of imatinib for treatment of gastrointestinal stromal tumors: a meta-analysis

OBJECTIVE

To investigate the efficacy and safety of standard-dose versus high-dose imatinib.

METHODS

After a systematic review of English language articles, five studies including 2008 patients were eligible for the meta-analysis. Data extracted from each study were synthesized into overall odds ratios (OR).

RESULTS

The overall OR for the high dose vs standard dose was 1.19 (95% CI 1.00-1.42) and the Z-score for the overall effect was 1.93 (P = 0.054), suggesting that high-dose imatinib added no survival benefits. The dose-related toxicity was also assessed in the same way. The rates of rash, hemorrhage, nausea, vomiting and taste disturbance increased as dose increased (P < 0.05), whereas the incidence of headache, abdominal pain, edema, fatigue, anemia, infection, muscle cramp and constipation was nearly identical and showed no significant difference.

CONCLUSIONS

Imatinib at a standard dose produces a similar effect to that at a high dose. The severity of the toxicity is associated with the dose of imatinib. However, larger and randomized studies are needed to draw definitive conclusions.

Monitoring of nonsteroidal immunosuppressive drugs in patients with lung disease and lung transplant recipients: American College of Chest Physicians evidence-based clinical practice guidelines

OBJECTIVES

Immunosuppressive pharmacologic agents prescribed to patients with diffuse interstitial and inflammatory lung disease and lung transplant recipients are associated with potential risks for adverse reactions. Strategies for minimizing such risks include administering these drugs according to established, safe protocols; monitoring to detect manifestations of toxicity; and patient education. Hence, an evidence-based guideline for physicians can improve safety and optimize the likelihood of a successful outcome. To maximize the likelihood that these agents will be used safely, the American College of Chest Physicians established a committee to examine the clinical evidence for the administration and monitoring of immunosuppressive drugs (with the exception of corticosteroids) to identify associated toxicities associated with each drug and appropriate protocols for monitoring these agents.

METHODS

Committee members developed and refined a series of questions about toxicities of immunosuppressives and current approaches to administration and monitoring. A systematic review was carried out by the American College of Chest Physicians. Committee members were supplied with this information and created this evidence-based guideline.

CONCLUSIONS

It is hoped that these guidelines will improve patient safety when immunosuppressive drugs are given to lung transplant recipients and to patients with diffuse interstitial lung disease.

Recombinant erythropoietin for the anaemia of patients with advanced Gastrointestinal Stromal Tumours (GIST) receiving imatinib: an active agent only in non progressive patients

Abstract

Recombinant erythropoietin for the anaemia of patients with advanced Gastrointestinal Stromal Tumours (GIST) receiving imatinib : an active agent only in non progressive patients.

Background

Imatinib is a standard treatment for advanced/metastatic GIST and in adjuvant setting. Anaemia is frequently observed in patients with advanced GIST, and is one of the most frequent side effects of imatinib with grade 3–4 anaemia in 10% of patients. Whether EPO treatment is useful in the management of GIST patients receiving imatinib treatment is unknown.

Methods

A retrospective study of EPO treatment in GIST patients receiving imatinib was undertaken in 4 centres. Thirty four patients received EPO treatment among the 319 GIST patients treated with imatinib in clinical trials or with compassionate use between 2001 and 2003. The efficacy of EPO on the anaemia of patients with GIST treated with imatinib was analyzed.

Results

There were 18 males and 16 females with a median age of 59 years. Median WHO-PS was 1. Primary tumour sites were mainly gastric (32%) and small bowel (29%). Sites of metastases were mainly liver (82%) and peritoneum (79%). The median delay between the initiation of imatinib treatment and EPO was 58 days (range 0–553). Median haemoglobin (Hb) level prior to EPO was 9 g/dL (range 6,9-11,8) and 11,7 g/dL (range 6,8-14,4) after 2 months. An increase of more than 2 g/dL was observed in 18 (53%) of patients. None of the 7 patients who progressed (PD) under imatinib treatment (400 mg/day) experienced HB response, as compared to 66% (18/27) of the remaining patients (PR + SD) (p = 0,002). Primary tumour site, liver metastases, peritoneal metastases, age, gender did not correlate with HB response to EPO. Response to EPO was observed in 2/11 patients receiving high-dose imatinib (800 mg/day) vs 16/23 of others. Using logistic regression, only PD before EPO treatment was retained as a predictive factor for EPO response.

Conclusion

EPO enables to increase Hb in most anaemic GIST patients who do not progress under imatinib, but not in patients with progressive disease.

What the emergency radiologist needs to know about treatment-related complications from conventional chemotherapy and newer molecular targeted agents

Emergency departments (ED) are increasingly utilized by oncology patients for disease- and treatment-related issues. With the increased use of new molecular targeted therapy (MTT) and conventional chemotherapeutic regimens, oncology patients present with a range of adverse treatment effects, some of which reveal characteristic injury patterns and imaging appearances. Knowledge of these imaging findings is critically important for early detection and prompt management in oncology patients. In this article, we present a brief review of conventional chemotherapeutic and new MTT regimens as well as address adverse reactions that bring oncology patients to the ED.

Updates on the management of gastrointestinal stromal tumors

Despite being the most common sarcoma of the gastrointestinal tract, gastrointestinal stromal tumor (GIST) has been widely recognized as a unique entity for just over a decade. The advent of tyrosine kinase inhibitors has revolutionized the diagnosis and treatment of GIST. Although surgery remains the only chance for cure, multimodal treatment that includes molecular therapy continues to develop. Optimal management of GIST requires careful radiographic, pathologic, medical, and surgical care, emphasizing the need for a multidisciplinary approach. This review highlights recent developments in the management of GIST.

Adjuvant imatinib therapy for gastrointestinal stromal tumors

Surgery is the standard of care for primary resectable gastrointestinal stromal tumors (GISTs), but half of surgically treated patients relapse. Imatinib (IM) has been shown to prolong recurrence-free survival after complete surgery and is now approved as adjuvant therapy (400  mg/day) for high-risk GIST patients. IM is well tolerated, with mild to moderate side effects observed. Whether adjuvant IM prolongs overall survival is under evaluation in two ongoing clinical trials.

Imatinib mesylate: past successes and future challenges in the treatment of gastrointestinal stromal tumors

Just over a decade ago, gastrointestinal tumours were a poorly understood mesenchymal neoplasm unsuccessfully treated with chemotherapy. Cytotoxic therapy for advanced disease yielded response rates of 10% and median survival of just 18 months. However, the discovery of KIT and platelet derived growth factor receptor alpha (PDGFRA) mutations as oncogenic drivers of most gastrointestinal tumours, paved the way for targeted therapy. Imatinib mesylate, a tyrosine kinase inhibitor, produces a clinical benefit rate (complete response, partial response, and stable disease) of more than 80% in metastatic setting and a median survival of 57 months. Imatinib is now also approved in adult patients following resection of KIT-positive GIST. Major insights into the mechanism of action of imatinib, unique pharmacokinetics, drug resistance, and management of low grade but chronic adverse effects continue to be made.

Serum Natrium Determines Outcome of Treatment of Advanced GIST with Imatinib: A Retrospective Study of 80 Patients from a Single Institution

Treatment with tyrosine kinase inhibitors (TKIs) has drastically improved overall survival (OS) of patients with advanced GIST. The aim of this study is to evaluate the results of treatment with different TKIs on advanced GIST and identify prognostic factors for OS. The medical records of all patients treated at the Department of Oncology, Aarhus University Hospital were retrospectively reviewed. Between 2001 and 2009, 80 patients with advanced GIST were treated with imatinib as first-line therapy. The median OS was 44 months (95% CI 31-56), and the 5-year OS was 40%. Since 2005, 32 patients were treated with sunitinib as 2nd-line therapy. The median time to progression was 9 months (95% CI: 3-13 months), and the 3-year OS was 30%. The data illustrate that data from large multicenter studies are reproducible in a single sarcoma centre. This retrospective study pointed to low serum sodium at the start of imatinib as a possible prognostic factor affecting OS.

Adjuvant imatinib for gastrointestinal stromal tumors: the current situation and problems

OBJECTIVE

To review the current situation and find out the current problems of adjuvant imatinib for gastrointestinal stromal tumors (GISTs).

METHODS

Searching for articles and records about imatinib for GISTs, especially adjuvant imatinib for GISTs, on MEDLINE, EMBASE and international conference on gastrointestinal.

RESULTS

GISTs are derived from mesenchymal cells of the gastrointestinal tract. The standard treatment for primary GISTs is to resect the tumor together with the negative margins completely without tumor rupture and spillage. Conventional chemotherapy and radiotherapy is ineffective for advanced GISTs. The introduction of imatinib has dramatically changed the natural history of advanced GISTs. Imatinib is generally safe and effective with doses of 400, 600 or 800 mg daily, and has become the standard drug in the treatment for patients with advanced GISTs. Furthermore, most of the toxicity of imatinib is minimal and manageable, almost no treatment-related deaths have been reported. Therefore, adjuvant imatinib therapy is safe and seems to improve recurrence-free survival after the resection of primary GISTs.

CONCLUSIONS

Although U.S Food and Drug Administration and European Medicines Agency have approved the use of adjuvant imatinib for GISTs postoperatively, a series of questions about the use of adjuvant imatinib still exist, such as the impact of adjuvant imatinib on overall survival, the optimal dose, the best duration of treatment and the most suitable patients. Doctors and patients should weigh the pros (the decrease of relapse) and cons (drug toxicity and drug costs), especially in terms of the benefit of overall survival.

Toxicity and monitoring of immunosuppressive therapy used in systemic autoimmune diseases

Systemic autoimmune diseases may be progressive and lead to organ system dysfunction and premature death. Current treatment paradigms are usually predominantly based on the administration of immunosuppressive and/or immunomodulatory drug therapy. Such therapy can stabilize systemic manifestations of connective tissue disease (CTD) and may put the disease into remission, and many of these agents are commonly used to treat CTD-associated interstitial lung disease (ILD). Although these agents have largely revolutionized the treatment of the systemic autoimmune diseases, adverse reactions, which can be serious and life threatening, to the various immunosuppressive agents used in the treatment of CTD can occur. Treating physicians must be aware of mechanisms of action of various immunosuppressive agents and be able to recognize the potential adverse reactions that may occur with therapy as well as potentially harmful effects on fetal development. Appropriate monitoring may prevent or limit toxicity from these agents, and knowledge of drug-drug interactions is essential when these agents are prescribed.

Principal long-term adverse effects of imatinib in patients with chronic myeloid leukemia in chronic phase

Imatinib mesylate (IM), an original Abl tyrosine kinase inhibitor, entered the clinics in 1998 for the treatment of patients with chronic myeloid leukemia (CML). The drug is universally considered the treatment of choice for most, if not all, patients with CML. Importantly, lessons learned from patients with CML have been applied successfully for the treatment of patients with other disorders where IM has since been found to be active by virtue of its ability to target other kinases, such as c-kit in patients with gastrointestinal stromal tumors. IM is associated with mild to moderate toxicity, mostly reversible by dose reduction or discontinuation of the drug. Most adverse effects occur within the first 2 years of starting therapy; however, late effects, many being unique, are now being recognized. In this report, we assess the toxicity associated with IM, with an emphasis on the long-term adverse effects.

Masitinib for the treatment of systemic and cutaneous mastocytosis with handicap: a phase 2a study

Treatment options for patients suffering from indolent forms of mastocytosis remain inadequate with the hyperactivation of mast cells responsible for many of the disease's systemic manifestations. Masitinib is a potent and highly selective oral tyrosine kinase inhibitor. A combined inhibition of c-Kit and Lyn make it particularly efficient in controlling the activity of mast cells and therefore, of potential therapeutic benefit in mastocytosis. Masitinib was administered to 25 patients diagnosed as having systemic or cutaneous mastocytosis with related handicap (i.e., disabilities associated with flushes, depression, pruritus and quality-of-life) at the initial dose levels of 3 or 6 mg/kg/day over 12 weeks. In accordance with the AFIRMM study, response was based upon change of clinical symptoms associated with patient handicap at week 12 relative to baseline, regardless of disease subtype. Improvement was observed in all primary endpoints at week 12 including a reduction of flushes, Hamilton rating, and pruritus as compared with baseline by 64% (P = 0.0005), 43% (P = 0.0049), and 36% (P = 0.0077), respectively. An overall clinical response was observed in 14/25 patients (56%; [95%CI = 37%-75%]), with sustainable improvement observed throughout an extension phase (>60 weeks). Common adverse events were edema (44%), nausea (44%), muscle spasms (28%), and rash (28%), the majority of which were of mild or moderate severity with a significant decline in frequency observed after 12 weeks of treatment. One patient experienced a serious adverse event of reversible agranulocytosis. Masitinib is a promising treatment for indolent forms of mastocytosis with handicap and indicates acceptable tolerability for long-term treatment regimens.

Gastrointestinal stromal tumor (GIST) recurrence following surgery: review of the clinical utility of imatinib treatment

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. Surgery with complete removal of the tumor is the primary treatment for resectable GIST and the only chance of cure. However, recurrence after surgery is common. The 2 main prognostic factors are the mitotic activity and the size of the tumor. Tumor rupture is also a risk factor for postoperative recurrence, and extra care should be taken while manipulating this soft and friable tumor. Imatinib mesylate (IM, Gleevec(®), Novartis, Basel, Switzerland) is a tyrosine kinase inhibitor and was first studied in the palliative setting for metastatic GIST patients in the year 2000. It is now the cornerstone of metastatic GIST treatment. IM also plays an important role as an adjuvant treatment for resectable GIST and has been shown to increase the recurrence-free survival in phase III studies. However, some points remain to be clarified. Notably, the ideal duration of adjuvant IM after surgery is still unclear. It is also difficult to determine the exact place of surgery in metastatic or recurrent GIST patients in the IM era. A multidisciplinary approach is, therefore, mandatory to offer GIST patients the best treatment available.

Imatinib induced severe skin reactions and neutropenia in a patient with gastrointestinal stromal tumor

BACKGROUND

Imatinib mesylate has been used for the treatment of unresectable or metastatic gastrointestinal stromal tumors (GIST). The current recommended dose of imatinib is 400 mg/day that is increased to 800 mg/day in cases with disease progression. However, imatinib can be associated with diverse adverse events, which has limited its use. We report a case of severe adverse skin reactions with neutropenic fever during imatinib treatment in a patient with GIST.

CASE PRESENTATION

A 71-year-old man was admitted with a one month history of epigastric pain and a palpable mass in the right upper quadrant. An abdominal CT scan revealed a 20 x 19 cm intraabdominal mass with tumor invasion into the peritoneum. Needle biopsy was performed and the results showed spindle shaped tumor cells that were positive for c-KIT. The patient was diagnosed with unresectable GIST. Imatinib 400 mg/day was started. The patient tolerated the first eight weeks of treatment. However, about three months later, the patient developed a grade 4 febrile neutropenia and a grade 3 exfoliative skin rash. The patient recovered from this serious adverse events after discontinuation of imatinib with supportive care. However, the skin lesions recurred whenever the patient received imatinib over 100 mg/day. Therefore, imatinib 100 mg/day was maintained. Despite the low dose imatinib, follow up CT showed a marked partial response without grade 3 or 4 toxicities.

CONCLUSION

The recommended dose of imatinib for the treatment of GIST is 400 mg/day but patients at risk for adverse drug reaction may benefit from lower doses. Individualized treatment is needed for such patients, and we may also try sunitinib as a alternative drug.

Practical management of tyrosine kinase inhibitor-associated side effects in GIST

Patients diagnosed with advanced gastrointestinal stromal tumor (GIST) are currently treated with oral tyrosine kinase inhibitors (TKIs). Imatinib mesylate is the standard first-line treatment, and sunitinib malate is administered second-line for patients who are intolerant or progress on imatinib. Imatinib has recently been approved for adjuvant treatment of GIST patients who have a significant risk for relapse. In both the metastatic and adjuvant settings, patients may be on these TKIs for many years. Low plasma imatinib levels have been reported to be associated with a short median time to progression of advanced GIST, stressing the importance of maintaining optimal drug levels. We summarize management of the most frequent and clinically significant adverse effects of imatinib and sunitinib in the treatment of GIST in the context of current guidelines, published literature, and the experience of three large GIST referral centers. The adverse events reviewed include nausea and vomiting, diarrhea, skin rash, musculoskeletal complaints, fatigue, hemorrhage, edema, hand-foot skin reaction, skin and hair discoloration, mucositis, hypertension, cardiac toxicity, hypothyroidism, liver transaminase changes, and hematological toxicity of imatinib and sunitinib. Potential drug-drug interactions with each respective agent are also discussed. With prudent use of supportive care measures, many side effects can be managed without dose reduction or interruption of treatment. On the other hand, individualized tailoring of the dose is often required to manage severe toxicity, such as painful hand-foot skin reactions, fatigue, hepatotoxicity, or cardiac toxicity. Management of many TKI-related adverse effects require further evaluation in prospective clinical trials.

The role of high-dose imatinib in the management of patients with gastrointestinal stromal tumor

After an era of few treatment options for patients with locally advanced or metastatic gastrointestinal stromal tumor (GIST), imatinib has emerged as the standard of care and first-line treatment for these patients. Although imatinib was initially approved at the doses of 400 and 600 mg daily, results from clinical studies established 400 mg daily as the standard initial dose for the majority of advanced GIST patients. Nevertheless, the use of high-dose imatinib (800 mg daily) has been shown to benefit patients with advanced or metastatic GIST that progresses on the standard-dose, and has been recommended in this setting by the major management guidelines in Europe and the United States. Results from the Meta-GIST meta-analysis showed that patients whose GIST harbors a KIT exon 9 mutation garner a longer progression-free survival time when treated initially with high-dose imatinib (800 mg daily) compared with those patients with KIT exon 11 or no mutations. Thus, the use of high-dose imatinib is recommended by the clinical practice guidelines in these 2 specific clinical situations. In addition, clinicians should weigh the clinical benefit of administering high-dose imatinib against the associated toxicities, as well as the proper management of dose-related side effects.

Targeted therapy for gastrointestinal stromal tumors: current status and future perspectives

Gastrointestinal stromal tumors (GISTs) present 80% of gastrointestinal tract mesenchymal tumors, with systemic chemotherapy and radiotherapy being unable to improve survival of patients with advanced disease. The identification of activating mutations in either KIT cell surface growth factor receptor or platelet-derived growth factor receptor alpha, which lead to ligand-independent signal transduction, paved the way for the development of novel agents that selectively inhibit key molecular events in disease pathogenesis. The development of imatinib mesylate in the treatment of metastatic GIST represents a therapeutic breakthrough in molecularly targeted strategies, which crucially improved patients' prognosis while its usefulness in adjuvant and neoadjuvant setting is under study. Sunitinib malate is available in the second-line setting, with ongoing studies evaluating its role in an earlier disease stage, while other targets are under intense investigation in order to enrich the therapeutical armamentarium for this disease. GIST phenotype seems to be an essential indicator of treatment response; thus, obtaining genotype information of each patient may be critical in order to tailor individualized treatment strategies and achieve maximal therapeutic results.