Targeted therapies for renal cell carcinoma: review of adverse event management strategies

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.

The ELR+CXCL chemokines and their receptors CXCR1/CXCR2: A signaling axis and new target for the treatment of renal cell carcinoma

The long-term efficacy of anti-angiogenesis drugs targeting vascular endothelial growth factor (VEGF) and VEGF receptors in the treatment of renal cell carcinoma (RCC) has been lacking. We have shown that the ELR⁺CXCL cytokines and their (C-X-C) chemokine receptors, namely CXCR1 and CXCR2, stimulate cancer cell proliferation, tumor inflammation, and angiogenesis. Hence, this essential molecular nexus regulating cancer growth represents a key therapeutic target.

Drug safety evaluation of sorafenib for treatment of solid tumors: consequences for the risk assessment and management of cancer patients

INTRODUCTION

Sorafenib is a multi-tyrosine kinase inhibitor (TKI). Considerable clinical experience has been accumulated since its first Phase III clinical trial in metastatic renal cancer patients in 2007. The management of its early acute toxicity in fit patients is well known. The management of prolonged treatment becomes the new challenge.

AREAS COVERED

Using sorafenib as a key word for PubMed search, we review preclinical and clinical data and discuss the pharmacokinetics and pharmacodynamics of sorafenib, its acute and cumulative toxicities and their consequences for patient management.

EXPERT OPINION

The systematic multi-disciplinary risk assessment of cancer patients prior to TKI initiation reduces the risks of acute and late toxicity, especially drug-drug interactions and arterial risks. Sarcopenia is now identified as a major risk of severe toxicity. The very diverse clinical pictures of cumulative toxicity must be known. The monitoring of sorafenib systemic exposure is helpful especially in elderly patients. Moreover, at disease progression, it allows distinguishing between underexposure to sorafenib and truly acquired resistance to the drug. The optimal use of sorafenib should allow improving the reported results of flat-dose. Finally, most of this knowledge could be used for the development and optimal use of the other TKIs.

Randomized Phase III Trial of Temsirolimus and Bevacizumab Versus Interferon Alfa and Bevacizumab in Metastatic Renal Cell Carcinoma: INTORACT Trial

Purpose

To prospectively determine the efficacy of combination therapy with temsirolimus plus bevacizumab versus interferon alfa (IFN) plus bevacizumab in metastatic renal cell carcinoma (mRCC).

Patients and Methods

In a randomized, open-label, multicenter, phase III study, patients with previously untreated predominantly clear-cell mRCC were randomly assigned, stratified by prior nephrectomy and Memorial Sloan-Kettering Cancer Center prognostic group, to receive the combination of either temsirolimus (25 mg intravenously, weekly) or IFN (9 MIU subcutaneously thrice weekly) with bevacizumab (10 mg/kg intravenously, every 2 weeks). The primary end point was independently assessed progression-free survival (PFS).

Results

Median PFS in patients treated with temsirolimus/bevacizumab (n = 400) versus IFN/bevacizumab (n = 391) was 9.1 and 9.3 months, respectively (hazard ratio [HR], 1.1; 95% CI, 0.9 to 1.3; P = .8). There were no significant differences in overall survival (25.8 ν 25.5 months; HR, 1.0; P = .6) or objective response rate (27.0% ν 27.4%) with temsirolimus/bevacizumab versus IFN/bevacizumab, respectively. Patients receiving temsirolimus/bevacizumab reported significantly higher overall mean scores in the Functional Assessment of Cancer Therapy–Kidney Symptom Index (FKSI) –15 and FKSI-Disease Related Symptoms subscale compared with IFN/bevacizumab (indicating improvement); however, no differences in global health outcome measures were observed. Treatment-emergent all-causality grade ≥ 3 adverse events more common (P < .001) with temsirolimus/bevacizumab were mucosal inflammation, stomatitis, hypophosphatemia, hyperglycemia, and hypercholesterolemia, whereas neutropenia was more common with IFN/bevacizumab. Incidence of pneumonitis with temsirolimus/bevacizumab was 4.8%, mostly grade 1 or 2.

Conclusion

Temsirolimus/bevacizumab combination therapy was not superior to IFN/bevacizumab for first-line treatment in clear-cell mRCC.

Tumoral CD105 is a novel independent prognostic marker for prognosis in clear-cell renal cell carcinoma

Background:

Angiogenesis is essential for tumour growth and metastasis. There are conflicting reports as to whether microvessel density (MVD) using the endothelial marker CD105 (cluster of differentiation molecule 105) in clear-cell renal cell carcinomas (ccRCC) is associated with prognosis. Recently, CD105 has been described as a RCC cancer stem cell marker.

Methods:

A total of 102 ccRCC were analysed. Representative tumour sections were stained for CD105. Vascularity (endothelial CD105) was quantified by MVD. The immunohistochemistry analysis detected positive (if present) or negative (if absent) CD105 tumoral staining. This retrospective population-based study was evaluated using Kaplan–Meier method, t-test and Cox proportional hazard model.

Results:

We found that the expression of endothelial CD105 (MVD) negatively correlated with nuclear grade (P<0.001), tumour stage (P<0.001) and Leibovitch score (P<0.001), whereas the expression of tumoral CD105 positively correlated with these three clinicopathological factors (P<0.001). In multivariate analysis, tumoral CD105 was found to be an independent predictor of poor overall survival (P=0.002).

Conclusions:

We have shown for the first time that tumoral CD105 is an independent predictive marker for death risk and unfavourable prognosis in patients with ccRCC after curative resection.

Targeted therapy of kidney cancer: keeping the art around the algorithms

BACKGROUND

Therapy for metastatic kidney cancer is actively evolving, particularly in the results of registration drug trials that have led to the approval of vascular endothelial growth factor pathway drugs such as sorafenib, sunitinib, pazopanib, bevacizumab, and axitinib, with focus on patients with good- or intermediate-risk criteria and clear cell histology. Mammalian target of rapamycin (mTOR) drugs such as everolimus and temsirolimus pivotal trials emphasize experiences in the setting of prior treatment or high-risk features. Interferon and interleukin 2 also are part of the treatment algorithms.

METHODS

The results of pivotal trials and the underlying context for the development of a cogent, cohesive treatment plan for an individual are reviewed, touching on decision points such as nephrectomy, metastasectomy, and medical initiation and discontinuation time points.

RESULTS

To the extent that these drug therapies are essential for achieving best outcomes for patients, these pivotal trial results and associated guidelines exist within a multidimensional, multidisciplinary context of many other disease features, comorbid features, and non-drug treatment decisions. Other dimensions include investigational targeted therapies, patient selection strategies, surgical strategies, and immunotherapies, some of which are in active development.

CONCLUSIONS

Clinicians should work toward the best use of drug sequencing and selection strategies based on core data derived from prospective randomized trials. To address individual patient needs, they should also recognize and emphasize individualized goals, to the extent that these are different from issues that were directly addressed in the trials.

Tivozanib for the treatment of metastatic renal cancer

Tyrosine kinase inhibitors have revolutionized the treatment of metastatic renal cell carcinoma (RCC). Drugs such as sorafenib, sunitinib and pazopanib act on the VEGF receptor pathway, but they can also inhibit other kinases, resulting in off-target toxicities. Tivozanib was developed due to its potency and selectivity against VEGF receptors 1-3. It has a favorable pharmacokinetic profile after oral administration and a long plasma half-life. In the Phase III TIVO-1 trial, it demonstrated a higher response rate and longer progression-free survival than sorafenib with a better side-effect profile. It is currently awaiting approval to be used in the first-line treatment of metastatic RCC. An early-phase trial has also shown its tolerability at full dose when given with the mTOR inhibitor temsirolimus, suggesting its potential in combination treatment. This article examines tivozanib from its laboratory to clinical development, as well as its relevance and future role in the treatment of RCC in the era of the tyrosine kinase inhibitors.

Pazopanib after sunitinib failure in patients with metastatic renal cell carcinoma

BACKGROUND

Sunitinib is a standard agent for the treatment of metastatic renal cell carcinoma (mRCC). The objective of the study was to evaluate efficacy and safety of pazopanib in the treatment of patients whose mRCC either progressed on sunitinib or who discontinued sunitinib due to adverse effects.

MATERIAL AND METHODS

Thirty-one consecutive mRCC patients who received pazopanib after sunitinib failure were included in this retrospective single center study. Pazopanib was continued until disease progression or intolerance. Treatment response was evaluated every 8-12 weeks according to the RECIST criteria. Adverse events were recorded according to the Common Terminology Criteria for Adverse Events.

RESULTS

Six patients (19%, 95% CI 12-26%) achieved partial response with pazopanib, 18 (58%) had stable disease, and seven (23%) progressive disease as their best response. Of the 14 patients who received pazopanib as their second-line therapy, six (43%) responded as compared with no responses among 17 patients treated in a later line (p = 0.004). The median progression-free survival time was 7.4 months after starting pazopanib (range, 0.9-15.6 months). Patients who received pazopanib as second-line treatment had median progression-free survival of 11.0 months as compared with 3.8 months among those who received pazopanib in a later line (p = 0.031). Only one (3%) patient discontinued pazopanib due to an adverse event. The most commonly recorded adverse events were anemia, thrombocytopenia, diarrhea, fatigue, and elevation of serum creatinine concentration. Six (19%) patients had one or more grade 3 or 4 adverse events recorded.

CONCLUSION

Pazopanib has clinical activity in mRCC as second-line agent after sunitinib failure suggesting lack of complete cross-resistance. Pazopanib was associated with acceptable toxicity, and may be considered as an option after sunitinib failure.

Temsirolimus for advanced renal cell carcinoma

Renal cell carcinomas (RCCs) represent one of the ten leading cancer entities with an increasing incidence especially in the western world. Unfortunately, about 25% of the patients develop metastatic RCC (mRCC) associated with a most unfavorable prognosis. In the recent years, various new agents targeting VEGF or VEGF receptor (VEGFR) or the mTOR pathway have been approved for the treatment of mRCC with significant prolongation of progression-free survival and, in part, of overall survival (OS). Targeting the mTOR kinase is an interesting option for mRCC. Temsirolimus, one of the available mTOR inhibitors, has been approved as a single agent in poor-risk mRCC patients based on the pivotal Phase III trial showing a significant superiority in OS versus IFN-α or temsirolimus + IFN-α, which has been verified by a pivotal Phase III trial. The benefit has been shown for clear cell carcinoma and papillary RCC as well. For poor prognosis patients, temsirolimus improves median survival by 3.6 months. In second-line treatment compared with sorafenib following first-line treatment with sunitinib temsirolimus showed a relative progression-free survival benefit for patients with nonclear cell RCC with temsirolimus. The median OS for the temsirolimus group was 12.27 and 16.64 months for the sorafenib group. In 2007, the US FDA granted approval for temsirolimus for the treatment of advanced RCC.

Randomized phase III trial of temsirolimus versus sorafenib as second-line therapy after sunitinib in patients with metastatic renal cell carcinoma

PURPOSE

This international phase III trial (Investigating Torisel As Second-Line Therapy [INTORSECT]) compared the efficacy of temsirolimus (mammalian target of rapamycin inhibitor) and sorafenib (vascular endothelial growth factor receptor [VEGFR] tyrosine kinase inhibitor) as second-line therapy in patients with metastatic renal cell carcinoma (mRCC) after disease progression on sunitinib.

PATIENTS AND METHODS

In total, 512 patients were randomly assigned 1:1 to receive intravenous temsirolimus 25 mg once weekly (n = 259) or oral sorafenib 400 mg twice per day (n = 253), with stratification according to duration of prior sunitinib therapy (≤ or > 180 days), prognostic risk, histology (clear cell or non-clear cell), and nephrectomy status. The primary end point was progression-free survival (PFS) by independent review committee assessment. Safety, objective response rate (ORR), and overall survival (OS) were secondary end points.

RESULTS

Primary analysis revealed no significant difference between treatment arms for PFS (stratified hazard ratio [HR], 0.87; 95% CI, 0.71 to 1.07; two-sided P = .19) or ORR. Median PFS in the temsirolimus and sorafenib arms were 4.3 and 3.9 months, respectively. There was a significant OS difference in favor of sorafenib (stratified HR, 1.31; 95% CI, 1.05 to 1.63; two-sided P = .01). Median OS in the temsirolimus and sorafenib arms was 12.3 and 16.6 months, respectively. Safety profiles of both agents were consistent with previous studies.

CONCLUSION

In patients with mRCC and progression on sunitinib, second-line temsirolimus did not demonstrate a PFS advantage compared with sorafenib. The longer OS observed with sorafenib suggests sequenced VEGFR inhibition may benefit patients with mRCC.

Metabolism and bioactivation of famitinib, a novel inhibitor of receptor tyrosine kinase, in cancer patients

BACKGROUND AND PURPOSE

Famitinib is a novel multi-targeted receptor tyrosine kinase inhibitor under development for cancer treatment. This study aims to characterize the metabolic and bioactivation pathways of famitinib.

EXPERIMENTAL APPROACH

The metabolites in human plasma, urine and feces were identified via ultra-high performance liquid chromatography-quadrupole-time of flight-mass spectrometry and confirmed using synthetic standards. Biotransformation and bioactivation mechanisms were investigated using microsomes, recombinant metabolic enzymes and hepatocytes.

KEY RESULTS

Famitinib was extensively metabolized after repeated oral administrations. Unchanged famitinib was the major circulating material, followed by N-desethylfaminitib (M3), whose steady-state exposure represented 7.2 to 7.5% that of the parent drug. Metabolites in the excreta were mainly from oxidative deamination (M1), N-desethylation (M3), oxidative defluorination (M7), indolylidene hydroxylation (M9-1 and M9-5) and secondary phase-II conjugations. CYP3A4/5 was the major contributor to M3 formation, CYP3A4/5 and aldehyde dehydrogenase to M1 formation and CYP1A1/2 to M7, M9-1 and M9-5 formations. Minor cysteine conjugates were observed in the plasma, urine and feces, implying the formation of reactive intermediate(s). In vitro microsomal studies proved that famitinib was bioactivated through epoxidation at indolylidene by CYP1A1/2 and spontaneously defluorinated rearrangement to afford a quinone-imine species. A correlation between famitinib hepatotoxicity and its bioactivation was observed in the primary human hepatocytes.

CONCLUSION AND IMPLICATIONS

Famitinib is well absorbed and extensively metabolized in cancer patients. Multiple enzymes, mainly CYP3A4/5 and CYP1A1/2, are involved in famitinib metabolic clearance. The quinone-imine intermediate formed through bioactivation may be associated with famitinib hepatotoxicity. Co-administered CYP1A1/2 inducers or inhibitors may potentiate or suppress its hepatotoxicity.

Signalling pathways in succinate dehydrogenase B-associated renal carcinoma

AIMS

Renal tumours have recently been described in association with mutations in the gene encoding the B subunit of succinate dehydrogenase, a mitochondrial Krebs cycle and electron transport chain enzyme (SDHB-associated renal cell carcinomas). The aim of this study was to investigate the roles of different signalling pathways in the pathogenesis of these tumours.

METHODS AND RESULTS

We used immunohistochemistry and antibodies against phospho-specific epitopes to examine the activity of three potential signalling pathways in tumour cells of three genetically confirmed cases of SDHB-associated renal cell carcinomas. We found no evidence supporting a role for either the mTOR [p-mTOR (Ser2448), p-S6 riboprotein (Ser235/236)] or hypoxia-inducible (carbonic anhydrase 9 and EGFR) pathways. However, there was immunohistochemical reactivity for phosphorylated AMP-dependent kinase (p-AMPK Thr172) and glycogen synthase kinase 3 (GSK3) phosphorylation (p-GSK3 Ser12), and nuclear expression of cyclin D1.

CONCLUSIONS

We suggest that these tumours may arise through a mechanism involving ATP depletion, activation of AMPK, and induction of cyclin D1, and that this may be a unique pathway of tumour development that has the potential for therapeutic intervention in these rare tumours.

Thyroid dysfunction as an unintended side effect of anticancer drugs

BACKGROUND

Several of the currently used anticancer drugs may variably affect thyroid function, with impairment ranging from modified total but not free concentration of thyroid hormones to overt thyroid disease.

SUMMARY

Cytotoxic agents seem to alter thyroid function in a relatively small proportion of adult patients. Anticancer hormone drugs may mainly alter serum levels of thyroid hormone-binding proteins without clinically relevant thyroid dysfunction. Old immunomodulating drugs, such as interferon-α and interleukin-2, are known to induce variably high incidence of autoimmune thyroid dysfunction. Newer immune checkpoint inhibitors, such as anti-CTLA4 monoclonal antibodies, are responsible for a relatively low incidence of thyroiditis and may induce secondary hypothyroidism resulting from hypophysitis. Central hypothyroidism is a well-recognized side effect of bexarotene. Despite their inherent selectivity, tyrosine kinase inhibitors may cause high rates of thyroid dysfunction. Notably, thyroid toxicity seems to be restricted to tyrosine kinase inhibitors targeting key kinase-receptors in angiogenic pathways, but not other kinase-receptors (e.g., epidermal growth factor receptors family or c-KIT). In addition, a number of these agents may also increase the levothyroxine requirement in thyroidectomized patients.

CONCLUSIONS

The pathophysiology of thyroid toxicity induced by many anticancer agents is not fully clarified and for others it remains speculative. Thyroid dysfunction induced by anticancer agents is generally manageable and dose reduction or discontinuation of these agents is not required. The prognostic relevance of thyroid autoimmunity, overt and subclinical hypothyroidism induced by anticancer drugs, the value of thyroid hormone replacement in individuals with abnormal thyrotropin following anticancer systemic therapy, and the correct timing of replacement therapy in cancer patients need to be defined more accurately in well-powered prospective clinical trials.

RNAi-mediated gene knockdown and anti-angiogenic therapy of RCCs using a cyclic RGD-modified liposomal-siRNA system

Angiogenesis is one of crucial processes associated with tumor growth and development, and consequently a prime target for cancer therapy. Although tumor endothelial cells (TECs) play a key role in pathological angiogenesis, investigating phenotypical changes in neovessels when a gene expression in TEC is suppressed is a difficult task. Small interfering RNA (siRNA) represents a potential agent due to its ability to silence a gene of interest. We previously developed a system for in vivo siRNA delivery to cancer cells that involves a liposomal-delivery system, a MEND that contains a unique pH-sensitive cationic lipid, YSK05 (YSK-MEND). In the present study, we report on the development of a system that permits the delivery of siRNA to TECs by combining the YSK-MEND and a ligand that is specific to TECs. Cyclo(Arg-Gly-Asp-D-Phe-Lys) (cRGD) is a well-known ligand to αVβ3 integrin, which is selectively expressed at high levels in TECs. We incorporated cRGD into the YSK-MEND (RGD-MEND) to achieve an efficient gene silencing in TECs. Quantitative RT-PCR and the 5' rapid amplification of cDNA ends PCR indicated that the intravenous injection of RGD-MEND at a dose of 4.0mg/kg induced a significant RNAi-mediated gene reduction in TEC but not in endothelial cells of other organs. Finally, we evaluated the therapeutic potency of the RGD-MEND encapsulating siRNA against vascular endothelial growth factor receptor 2. A substantial delay in tumor growth was observed after three sequential RGD-MEND injections on alternate days. In conclusion, the RGD-MEND represents a new approach for the characterization of TECs and for us in anti-angiogenic therapy.

Meta-analysis identifies NF-κB as a therapeutic target in renal cancer

OBJECTIVE

To determine the expression patterns of NF-κB regulators and target genes in clear cell renal cell carcinoma (ccRCC), their correlation with von Hippel Lindau (VHL) mutational status, and their association with survival outcomes.

METHODS

Meta-analyses were carried out on published ccRCC gene expression datasets by RankProd, a non-parametric statistical method. DEGs with a False Discovery Rate of < 0.05 by this method were considered significant, and intersected with a curated list of NF-κB regulators and targets to determine the nature and extent of NF-κB deregulation in ccRCC.

RESULTS

A highly-disproportionate fraction (~40%; p < 0.001) of NF-κB regulators and target genes were found to be up-regulated in ccRCC, indicative of elevated NF-κB activity in this cancer. A subset of these genes, comprising a key NF-κB regulator (IKBKB) and established mediators of the NF-κB cell-survival and pro-inflammatory responses (MMP9, PSMB9, and SOD2), correlated with higher relative risk, poorer prognosis, and reduced overall patient survival. Surprisingly, levels of several interferon regulatory factors (IRFs) and interferon target genes were also elevated in ccRCC, indicating that an 'interferon signature' may represent a novel feature of this disease. Loss of VHL gene expression correlated strongly with the appearance of NF-κB- and interferon gene signatures in both familial and sporadic cases of ccRCC. As NF-κB controls expression of key interferon signaling nodes, our results suggest a causal link between VHL loss, elevated NF-κB activity, and the appearance of an interferon signature during ccRCC tumorigenesis.

CONCLUSIONS

These findings identify NF-κB and interferon signatures as clinical features of ccRCC, provide strong rationale for the incorporation of NF-κB inhibitors and/or and the exploitation of interferon signaling in the treatment of ccRCC, and supply new NF-κB targets for potential therapeutic intervention in this currently-incurable malignancy.

Thyroid dysfunction and tyrosine kinase inhibitors in renal cell carcinoma

The most recent World Health Organization classification of renal neoplasms encompassed nearly 50 distinctive renal neoplasms. Different histological subtypes have different clinical outcomes and show different responses to therapy. Overall, the incidence of kidney cancer has increased worldwide in the last years. Although the most common type of kidney cancer is localized renal cell carcinoma (RCC), with a 5-year survival rate of 85%, about one third of patients present advanced or metastatic disease at diagnosis, with a 5-year survival rate of only 10%. Multi-targeted receptor tyrosine kinase inhibitors (TKIs, sunitinib and sorafenib), the anti-VEGF MAB bevacizumab in association with interferon-α, and the mTOR inhibitors are now approved for the treatment of mRCC. Recently, the novel agents pazopanib and axitinib have also demonstrated efficacy in mRCC patients. Several recent retrospective and prospective trials have suggested that some of their adverse events, such as hypertension, hypothyroidism, and hand foot syndrome (HFS) may act as potential biomarkers of response and efficacy of treatment. In this review, we analyzed the studies that have suggested a relationship between hypothyroidism onset and a better outcome of mRCC patients treated with TKIs. The biological mechanisms suggesting and explaining this correlation are not well known and different speculative theories have been considered in order to investigate the clinical link between hypothyroidism occurrence and the prolonged therapy with TKIs in solid tumors. Furthermore, the management of this unexplained side effect is very important to maximize the efficacy of therapy in mRCC patients because there is a clear and consistent relationship between drug dose and efficacy of treatment. Certainly, other studies are needed to clarify whether a better outcome is associated with hypothyroidism induced to TKIs in patients with mRCC.

BS, Vuyyuru H, Muthuvel B, Konerirajapuram Natrajan S. CTR1 silencing inhibits angiogenesis by limiting copper entry into endothelial cells

Increased levels of intracellular copper stimulate angiogenesis in human umbilical vein endothelial cells (HUVECs). Copper transporter 1 (CTR1) is a copper importer present in the cell membrane and plays a major role in copper transport. In this study, three siRNAs targeting CTR1 mRNA were designed and screened for gene silencing. HUVECs when exposed to 100 µM copper showed 3 fold increased proliferation, migration by 1.8-fold and tube formation by 1.8-fold. One of the designed CTR1 siRNA (si 1) at 10 nM concentration decreased proliferation by 2.5-fold, migration by 4-fold and tube formation by 2.8-fold. Rabbit corneal packet assay also showed considerable decrease in matrigel induced blood vessel formation by si 1 when compared to untreated control. The designed si 1 when topically applied inhibited angiogenesis. This can be further developed for therapeutic application.

The use of targeted therapies in pancreatic neuroendocrine tumours: patient assessment, treatment administration, and management of adverse events

Together with the use of novel oral targeted therapies, a multidisciplinary approach can be used to effectively treat patients with advanced pancreatic neuroendocrine tumours (pNETs). Here we review the integration of the oncology nurse to the newly developed oral treatment setting for patients with pNETs. From the outset, the nurse must be involved in various processes, including performance of baseline assessments (e.g. blood pathology, cardiac and lung function testing, patient history) and general medical observations, treatment administration, dietary guidance, evaluation of comorbidities, and review of concomitant medications. Patient education and establishment of a strong partnership in care before the start of pNET therapy ultimately increase treatment adherence and reduce potential toxicities. Regular review of general patient status and disease progression and continuous monitoring of adverse events also help enhance treatment outcomes and subsequently improve quality of life. Nurses' knowledge of agent-specific toxicities and prompt, proactive management is a critical aspect of care. In essence, as the pNET treatment landscape evolves, the role of the healthcare professional in overall patient care must shift accordingly.

Functional diversity and pharmacological profiles of the FKBPs and their complexes with small natural ligands

From 5 to 12 FK506-binding proteins (FKBPs) are encoded in the genomes of disparate marine organisms, which appeared at the dawn of evolutionary events giving rise to primordial multicellular organisms with elaborated internal body plan. Fifteen FKBPs, several FKBP-like proteins and some splicing variants of them are expressed in humans. Human FKBP12 and some of its paralogues bind to different macrocyclic antibiotics such as FK506 or rapamycin and their derivatives. FKBP12/(macrocyclic antibiotic) complexes induce diverse pharmacological activities such as immunosuppression in humans, anticancerous actions and as sustainers of quiescence in certain organisms. Since the FKBPs bind to various assemblies of proteins and other intracellular components, their complexes with the immunosuppressive drugs may differentially perturb miscellaneous cellular functions. Sequence-structure relationships and pharmacological profiles of diverse FKBPs and their involvement in crucial intracellular signalization pathways and modulation of cryptic intercellular communication networks were discussed.

[Surgery of inferior vena cava-associated urological tumor lesions]

BACKGROUND

Tumor lesions of the inferior vena cava are extremely challenging with regard to adequate therapeutic management also in advanced malignant urological tumor lesions which can be caused by malignant adhesion, impression and tumor infiltration from the surrounding tissue. This can be the case with metastases from a seminoma or testicular carcinoma (differential diagnosis: primary vena cava leiomyosarcoma), tumor-associated growth into and within the inferior vena cava originating from renal cell carcinoma or carcinoma of the pararenal gland. The aim of this overview was to summarize current clinical and operative experiences in the treatment of inferior vena cava-associated urological tumor lesions, perioperative management, individual-specific and finding-adapted surgical technique and possible outcome, including prognostic considerations from clinical daily practice and representative data found in the literature.

BASIC STATEMENTS

The primary aim of the surgical approach is to achieve R0 resection with reconstruction of the inferior vena cava lumen providing a reasonable risk-benefit ratio, which comprises i) complete resection and substitution of the inferior vena cava by a prosthesis along the previous extent of tumor growth, ii) partial resection of the vena cava wall with subsequent patch-plasty or tangential resection with primary suture or iii) removal of the vena cava thrombus after cavotomy. Particular attention should be paid to tumor thrombi reaching the right atrium which need to be extracted after sternotomy and atriotomy using an extracorporeal circulation (cardiac surgeon). For surgical planning, subdivision of the inferior vena cava into three segments, infracardiac, infrahepatic and infrarenal third, has been proven and tested.

CONCLUSIONS

The current development status and advances in surgical approaches as well as advances in medical technology allow the successful approach to such advanced stage urological tumor manifestations. A deciding factor is the abdominal and cardiovascular surgical expertise of each surgeon after formation of a team of surgical specialists (including urologists) and only then prognostic advantages can be achieved.

Adjuvant therapy in renal cell carcinoma-past, present, and future

To date, no effective adjuvant treatment for renal cell carcinoma (RCC) has been described, but research in this area is important since the 5-year relapse rate for intermediate- and high-risk early-stage RCC is 30%-40%. Metastatic RCC can be treated successfully with immune therapy and targeted therapy. Adjuvant trials with immune therapy have been conducted, but they reported no benefit in disease-free survival, and clinical trials with targeted agents have not yet reported results. Further advances in our understanding of the molecular pathogenesis of RCC will identify additional potential targets for adjuvant treatment trials. Future challenges will consequently include target identification, as well as trial design to answer multiple trial questions concurrently, comprehensively, and economically. We review the past efforts, summarize the current adjuvant clinical trial landscape, and consider the challenges in adjuvant trials for RCC. Additionally, we identify potential future adjuvant trial treatments and propose an alternative design for future adjuvant clinical trials.

[Anticancer drug adherence]

A large number of anticancer drugs have been introduced during the two last decades with significant impact for survival, making cancer a chronic disease in a growing number of indications. However, these drugs are costly, induce adverse effects and their efficacy frequently depends on the dose. For all these reasons, adherence in cancer therapy is critical for an optimal benefit-risk ratio. Patient adherence remains virtually unexplored in many cancers, such as malignant blood diseases. When measured, adherence is poor, especially when the drug is administered as oral and prolonged therapy (hormonotherapy in breast cancer, imatinib). Physician nonadherence represents another form of drug misadministration; poorly documented, its mechanism remains obscure. Adherence may be measured by a panel of methods, each of them displaying limits and pitfalls, suggesting that several complementary methods should be used in the context of prospective studies. Risk factors are age, socio-educative profile, disease stage and physician profile. This review emphasizes some methods to prevent nonadherence. Finally, this review argues for prospective studies, which should integrate a social pharmacology approach, including medicine, psycho-sociology and economics.

Life-threatening gastrointestinal bleeding during targeted therapy for advanced renal cell carcinoma: a case report

Background

Temsirolimus has important clinical activity in both untreated and previously treated patients with advanced renal cell carcinoma. Targeted therapy–related stomatitis and mucositis have occurred during targeted therapies, but there is no consensus on which strategy is the most effective. We herein report a case in which several sessions of endoscopic hemostasis with argon plasma coagulation (APC) effectively resolved life-threatening gastrointestinal bleeding that had occurred during targeted therapy. This is the first case report of such an adverse drug reaction in the literature.

Case presentation

A 47-year-old female patient with advanced renal cell carcinoma was treated with temsirolimus. Eight weeks after starting targeted therapy, the patient was admitted to our hospital for worsened fatigue, pallor, and hematemesis. A complete blood count showed a marked drop in her hemoglobin level from 10.1 g/dl 4 days earlier to 2.9 g/dl. Esophagogastroduodenoscopy revealed diffuse mucosal bleeding of the antrum. Endoscopy revealed diffuse reddish spots that resembled gastric antral vascular ectasia (GAVE) extending from the pylorus into the antrum. One month after endoscopic hemostasis with APC and stopping temsirolimus, significant improvement was shown in the gastric erythema and GAVE like lesions.

Conclusion

Minor hemorrhagic events are relatively common in patients treated with targeted agents. Life-threatening hemorrhagic events are rarer than minor hemorrhagic complications. In the present case, endoscopic hemostasis with APC effectively prevented severe anemia and blood loss due to gastrointestinal bleeding.

Everolimus does not further reduce polycystic liver volume when added to long acting octreotide: results from a randomized controlled trial

BACKGROUND & AIMS

Polycystic liver disease (PLD) is associated with autosomal dominant polycystic kidney disease (ADPKD) or autosomal dominant polycystic liver disease (PCLD). The resulting hepatomegaly compromises quality of life. Somatostatin analogues reduce PLD volume by approximately 5% when given for 6-12 months. A pilot trial in 16 ADPKD patients demonstrated that sirolimus, an mTOR inhibitor, reduced PLD volume by 26%. The aim of this study was to assess the PLD volume reducing effect of everolimus and octreotide relative to octreotide monotherapy.

METHODS

We designed a randomized controlled trial that compared 48 weeks of everolimus 2.5 mg daily, combined with octreotide 40 mg intramuscularly every 4 weeks, to octreotide monotherapy. We included PCLD and ADPKD patients. Exclusion criteria were MDRD-GFR <60 ml/min/1.73 m(2) and liver volume <2500 ml. Primary outcome was change in liver volume measured with CT-volumetry.

RESULTS

We randomized 44 PLD patients (29 PCLD, 15 ADPKD, 89% female) to treatment with octreotide (n=23) or octreotide-everolimus (n=21). Liver volume decreased by 3.5% (p<0.01) in the monotherapy arm, compared to 3.8% with combination therapy (p<0.01). The difference between treatment arms was not significant (p=0.73).

CONCLUSIONS

Adding everolimus to octreotide in PLD does not increase the liver volume reducing effect of octreotide.

Understanding, recognizing, and managing toxicities of targeted anticancer therapies

Answer questions and earn CME/CNE Advances in genomics and molecular biology have identified aberrant proteins in cancer cells that are attractive targets for cancer therapy. Because these proteins are overexpressed or dysregulated in cancer cells compared with normal cells, it was assumed that their inhibitors will be narrowly targeted and relatively nontoxic. However, this hope has not been achieved. Current targeted agents exhibit the same frequency and severity of toxicities as traditional cytotoxic agents, with the main difference being the nature of the toxic effects. Thus, the classical chemotherapy toxicities of alopecia, myelosuppression, mucositis, nausea, and vomiting have been generally replaced by vascular, dermatologic, endocrine, coagulation, immunologic, ocular, and pulmonary toxicities. These toxicities need to be recognized, prevented, and optimally managed.

Risk of infections in renal cell carcinoma (RCC) and non-RCC patients treated with mammalian target of rapamycin inhibitors

Background:

Mammalian target of rapamycin (mTOR) inhibitors are used in a variety of malignancies. Infections have been reported with these drugs. We performed an up-to-date meta-analysis to further characterise the risk of infections in cancer patients treated with these agents.

Methods:

Pubmed and oncology conferences' proceedings were searched for studies from January 1966 to June 2012. Studies were limited to phase II and III randomised controlled trials (RCTs) of everolimus or temsirolimus reporting on cancer patients with adequate safety profiles. Summary incidences, relative risks (RRs), and 95% confidence intervals (CIs) were calculated.

Results:

A total of 3180 patients were included. The incidence of all-grade and high-grade infections due to mTOR inhibitors was 33.1% (95% CI, 24.5–43.0%) and 5.6% (95% CI, 3.8–8.3%), respectively. Compared with controls, the RR of all-grade and high-grade infections due to mTOR inhibitors was 2.00 (95% CI, 1.76–2.28, P<0.001) and 2.60 (95% CI, 1.54–4.41, P<0.001), respectively. Subgroup analysis found no difference in incidences or risks between everolimus and temsirolimus or between different tumour types (renal cell carcinoma (RCC) vs non-RCC). Infections included respiratory tract (61.7%), genitourinary (29.4%), skin/soft tissue (4.2%), and others (4.9%).

Conclusion:

Treatment with mTOR inhibitors is associated with a significant increase in risk of infections. Close monitoring for any signs of infections is warranted.

Overcoming endocrine resistance in breast cancer: importance of mTOR inhibition

Approaches to treatment for many patients with advanced breast cancer are based on the expression of specific receptors. Treatments targeting the hormone receptor (typically the estrogen receptor) are used to reduce signaling through these receptors and thereby inhibit proliferation of breast cancer cells expressing these receptors. Although these treatments are effective for many patients, resistance to treatment is common. Recent clinical trials suggest that using multiple agents targeting the same pathway is not sufficient to overcome resistance. New treatment approaches are needed for these patients. Inhibition of the mTOR signaling pathway, a key point of confluence for multiple signaling cascades, offers a promising approach to restoring sensitivity to endocrine therapy in breast cancer. This article reviews the current data from studies of mTOR inhibitors everolimus and temsirolimus in combination with endocrine therapies to overcome treatment resistance in patients with advanced breast cancer.

Ovatodiolide Targets β -Catenin Signaling in Suppressing Tumorigenesis and Overcoming Drug Resistance in Renal Cell Carcinoma

Dysregulated β-catenin signaling is intricately involved in renal cell carcinoma (RCC) carcinogenesis and progression. Determining potential β-catenin signaling inhibitors would be helpful in ameliorating drug resistance in advanced or metastatic RCC. Screening for β-catenin signaling inhibitors involved in silico inquiry of the PubChem Bioactivity database followed by TCF/LEF reporter assay. The biological effects of ovatodiolide were evaluated in 4 RCC cell lines in vitro and 2 RCC cell lines in a mouse xenograft model. The synergistic effects of ovatodiolide and sorafenib or sunitinib were examined in 2 TKI-resistant RCC cell lines. Ovatodiolide, a pure compound of Anisomeles indica, inhibited β-catenin signaling and reduced RCC cell viability, survival, migration/invasion, and in vitro cell or in vivo mouse tumorigenicity. Cytotoxicity was significantly reduced in a normal kidney epithelial cell line with the treatment. Ovatodiolide reduced phosphorylated β-catenin (S552) that inhibited β-catenin nuclear translocation. Moreover, ovatodiolide decreased β-catenin stability and impaired the association of β-catenin and transcription factor 4. Ovatodiolide combined with sorafenib or sunitinib overcame drug resistance in TKI-resistant RCC cells. Ovatodiolide may be a potent β-catenin signaling inhibitor, with synergistic effects with sorafenib or sunitinib, and therefore, a useful candidate for improving RCC therapy.

Targeting FGFR with dovitinib (TKI258): preclinical and clinical data in breast cancer

PURPOSE

Fibroblast growth factor receptor 1 (FGFR1) and FGFR2 amplifications are observed in approximately 10% of breast cancers and are related to poor outcomes. We evaluated whether dovitinib (TKI258), an inhibitor of FGFR1, FGFR2, and FGFR3, presented antitumor activity in FGFR-amplified breast cancers.

EXPERIMENTAL DESIGN

Preclinical activity of dovitinib was evaluated in both breast cancer cell lines and an FGFR1-amplified xenograft model (HBCx2). Dovitinib was then evaluated in a phase II trial that included 4 groups of patients with human EGF receptor 2-negative metastatic breast cancer on the basis of FGFR1 amplification and hormone receptor (HR) status. FGFR1 amplification was assessed by silver in situ hybridization. Preplanned retrospective analyses assessed predictive value of FGFR1, FGFR2, and FGF3 amplifications by quantitative PCR (qPCR).

RESULTS

Dovitinib monotherapy inhibits proliferation in FGFR1- and FGFR2-amplified, but not FGFR-normal, breast cancer cell lines. Dovitinib also inhibits tumor growth in FGFR1-amplified breast cancer xenografts. Eighty-one patients were enrolled in the trial. Unconfirmed response or stable disease for more than 6 months was observed in 5 (25%) and 1 (3%) patient(s) with FGFR1-amplified/HR-positive and FGFR1-nonamplified/HR-positive breast cancer. When qPCR-identified amplifications in FGFR1, FGFR2, or FGF3 were grouped to define an FGF pathway-amplified breast cancer in HR-positive patients, the mean reduction in target lesions was 21.1% compared with a 12.0% increase in patients who did not present with FGF pathway-amplified breast cancer.

CONCLUSION

Dovitinib showed antitumor activity in FGFR-amplified breast cancer cell lines and may have activity in breast cancers with FGF pathway amplification.

Incidence and risk of treatment-related mortality in cancer patients treated with the mammalian target of rapamycin inhibitors

BACKGROUND

Inhibition of the mammalian target of rapamycin (mTOR) is an established treatment for multiple malignancies. We carried out an up-to-date meta-analysis to determine the risk of fatal adverse events (FAEs) in cancer patients treated with mTOR inhibitors.

PATIENTS AND METHODS

PubMed, conferences and clinicaltrials.gov databases were searched for articles reported from January 1966 to June 2012. Eligible studies were limited to approved mTOR inhibitors (everolimus and temsirolimus) and reported on patients with cancer, randomized design and adequate safety profiles. Data extraction was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

RESULTS

In all, 3193 patients from eight randomized, controlled trials (RCTs) were included, 2236 from everolimus trials and 957 from temsirolimus trials. The relative risk (RR) of FAEs related to mTOR inhibitors use was 2.20 (95% CI, 1.25-3.90; P = 0.006) compared with control patients. On subgroup analysis, no difference in the rate of FAEs was found between everolimus and temsirolimus or between tumor types [renal cell carcinoma (RCC) versus non-RCC]. No evidence of publication bias was observed.

CONCLUSION

The use of mTOR inhibitors is associated with a small but higher risk of FAEs compared to control patients. In the appropriate clinical scenario, the use of these drugs remains justified in their approved indications.

NF-κB inhibition by bortezomib permits IFN-γ-activated RIP1 kinase-dependent necrosis in renal cell carcinoma

Advanced renal cell carcinoma (RCC) is an invariably fatal cancer. Currently, small-molecule inhibitors that target cell growth, angiogenesis, or nutrient-sensing pathways represent the primary pharmacologic interventions for this disease, but these inhibitors only delay tumor progression and are not curative. The cytokine IFN-γ showed the potential to provide lasting remission in several phase I/II trials for advanced RCCs, but subsequent trials, including a multicenter phase III study using IFN-γ as a monotherapy for RCCs, were less promising. Notably, these trials were designed to exploit the indirect immunomodulatory effects of IFN-γ, whereas its direct antitumor properties--including its ability to trigger programmed cell death in tumors-remain mostly untapped. Here, we show that the proteasome inhibitor bortezomib (PS-341, Velcade) sensitizes otherwise resistant RCC cells to direct necrotic death by IFN-γ. Mechanistically, we show that bortezomib functions, at least in part, by inhibiting prosurvival NF-κB signaling. In the absence of this signal, IFN-γ triggers programmed necrosis (or "necroptosis") dependent on the kinase RIP1. When taken together with the observation that NF-κB signaling is elevated in RCCs, these results provide rationale for the combined use of IFN-γ and bortezomib in the treatment of metastatic RCCs.

Effects of tyrosine kinase inhibitors on rat isolated heart function and protein biomarkers indicative of toxicity

INTRODUCTION

Cardiac toxicity, manifested as diminished contractility, ischemic heart disease, and heart failure is a major issue in drug safety. Concerns revolve around targeted drugs (TKIs) where contractility effects were not anticipated. The ability to predict cardiac toxicity early would help to de-risk drugs in development and prepare physicians to manage risk in the clinic. Issues with current preclinical studies include insufficient testing with informative, translatable models, and predictive biomarkers. The isolated heart model is amenable to multiple assessments which can be combined with current technologies to assess toxicity on a multi-scale level.

METHODS

Rat isolated heart model was used to assess changes in left ventricular (LV) contractility and protein biomarkers BNP, IL6, TNFα, and cardiac troponins T (TnT) and I (TnI). Responses were assessed during perfusion with modified Henseleit Krebs (MHK), and 20 min concentration escalations of verapamil, carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP), isoproterenol, or 20 min escalations bracketing clinical blood concentrations of sunitinib, sorafenib, and erlotinib. LV parameters and effluent for biomarkers were collected before and during escalating drug concentrations.

RESULTS

Verapamil reduced inotropy with no change in biomarkers, FCCP and isoproterenol reduced and increased heart function respectively and increased TnT and TNFα. Erlotinib had no significant effects on function or biomarkers. Sunitinib diminished function, increased TNFα at 0.1 μM, and increased TnT at higher concentrations. Sorafenib dose dependently increased TNFα beginning at 0.1 μM, reducing contractility and flow rate at 0.6 μM.

DISCUSSION

The ex-vivo assay is a sensitive and predictive model for assessing changes in heart function and biomarkers of toxicity and injury. This assay demonstrates the potential for sunitinib and sorafenib to cause cardiac toxicity in humans. Also, TNFα appears to be a biomarker in the heart prior to injury. Due to its versatility, the isolated heart assay has potential to fill gaps in cardiac safety testing early in drug development.

Adherence Issues for Oral Antineoplastics

Nonadherence to antineoplastics is a growing concern because of the increasing number of novel oral targeted anticancer therapies. Many of these agents are administered on a chronic continuous schedule for an indefinite period of time where adherence is crucial to achieve optimal disease control and prolong survival. Many factors are known to contribute to medication nonadherence. Prevention, early detection, and management of adverse drug reactions associated with oral targeted therapies require close vigilance. Knowing how to prevent and manage adverse drug reactions will help clinicians develop strategies to promote patient adherence to oral anticancer treatment regimens. Optimal adherence requires a dynamic patient-provider alliance through education, communication, ongoing monitoring, and follow-up.

Risk of hypothyroidism in patients with cancer treated with sunitinib: a systematic review and meta-analysis

BACKGROUND

The multitargeted tyrosine kinase inhibitor sunitinib is used in various cancers. Clinical studies have reported a substantial variation in the incidence of hypothyroidism associated with sunitinib, without a systemic attempt to synthesize these data.

METHODS

We searched Medline databases for relevant clinical trials published up to May 2012. Phase II and III trials and expanded access programs of sunitinib in patients with any type of cancer that reported occurrence of hypothyroidism were eligible. The summary incidence, relative risk (RR) and 95% confidence intervals (CIs) were calculated using random- or fixed-effects models based on the heterogeneity of included studies.

RESULTS

Incidence analysis was performed using 6678 sunitinib-treated patients from all 24 eligible trials. The incidence of all- and high-grade hypothyroidism was 9.8% (95% CI 7.3-12.4%) and 0.4% (95% CI 0.3-0.5%), respectively. A meta-analysis of seven randomized trials with 2787 subjects revealed a RR of all- and high-grade hypothyroidism of 13.95 (95% CI 6.91-28.15; p < 0.00001) and 4.78 (95% CI 1.09-20.84; p = 0.04), respectively. Subgroup analysis revealed a significantly higher incidence of all-grade hypothyroidism in patients receiving sunitinib for longer duration than in patients receiving sunitinib for shorter duration (p = 0.02).

CONCLUSIONS

This meta-analysis of data available from clinical trials demonstrates that sunitinib is associated with a significant risk of developing all- and high-grade hypothyroidism. These data provide further evidence to recommend monitoring for hypothyroidism in patients receiving sunitinib.

The tumor-suppressive function of UNC5D and its repressed expression in renal cell carcinoma

PURPOSE

As a newly added member of the UNC5H receptors, the function of UNC5D/H4 in tumorigenesis remains poorly defined. The aim of this study was to examine the expression of UNC5D in primary renal cell carcinomas (RCC), analyze the mechanisms responsible for its downregulation in RCC, and assess its functional relevance to tumor growth and migration.

EXPERIMENTAL DESIGN

Forty-four paired primary RCCs and corresponding adjacent noncancerous tissues were collected. The mRNA and protein expression level of UNC5D was assessed by reverse transcriptase-PCR, real-time PCR, or immunohistochemistry. Epigenetic alterations in UNC5D promoter and LOH in the UNC5D locus were also analyzed. Ectopic expression of UNC5D in renal cancer cells with silenced expression of UNC5D was used for analysis of the biologic functions of UNC5D.

RESULTS

UNC5D expression was attenuated in multiple carcinoma cell lines including renal cancer cells. Similar reduction was also observed in primary RCC tissues as compared with paired adjacent noncancerous tissues. Methylation-specific PCR showed hypermethylation in UNC5D promoter in a significant proportion (18 of 44) of tumor tissue (40.9%). LOH of UNC5D was observed in 13 of 44 patients with RCCs (29.5%). Restoration of UNC5D expression in renal cancer cells significantly inhibited cell proliferation, anchorage-dependent and -independent growth, as well as migration and invasion, whereas knockdown of UNC5D promoted cell growth. Furthermore, ectopic expression of UNC5D induced G2-M cell-cycle arrest.

CONCLUSIONS

UNC5D is a functional tumor suppressor that is frequently downregulated in RCCs due to promoter hypermethylation and LOH.

Practical management of everolimus-related toxicities in patients with advanced solid tumors

Everolimus is an orally administered inhibitor of the mammalian target of rapamycin (mTOR), an intracellular protein kinase downstream of the phosphatidylinositol 3-kinase/AKT pathway involved in key components of tumorigenesis, including cell growth, proliferation, and angiogenesis. In the advanced cancer setting, based on favorable results from phase III trials, everolimus is indicated for the treatment of advanced renal cell carcinoma, advanced neuroendocrine tumors of pancreatic origin, and advanced hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer. Additional oncology indications for everolimus include renal angiomyolipoma with tuberous sclerosis complex and subependymal giant-cell astrocytoma. Although it is generally well tolerated, with most adverse events of mild to moderate severity and manageable, everolimus exhibits a distinct adverse event profile that warrants guidance for proper diagnostic and medical management. This guidance is particularly important given the potential for widespread long-term use of everolimus. This review will focus on the most relevant toxicities associated with mTOR inhibitors and on their management. Practical treatment recommendations are presented for stomatitis, noninfectious pneumonitis, rash, selected metabolic abnormalities, and infections. Provided these events are rapidly identified and treated, the vast majority should resolve with minimal effect on treatment outcomes and patients' quality of life.