A phase 2 study with a daily regimen of the oral mTOR inhibitor RAD001 (everolimus) in patients with metastatic clear cell renal cell cancer

Activation of AMPK participates hydrogen sulfide-induced cyto-protective effect against dexamethasone in osteoblastic MC3T3-E1 cells

Long-time glucocorticoids (GCs) usage causes osteoporosis. In the present study, we explored the potential role of hydrogen sulfide (H2S) against dexamethasone (Dex)-induced osteoblast cell damage, and focused on the underlying mechanisms. We showed that two H2S-producing enzymes, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE), were significantly downregulated in human osteonecrosis tissues as well as in Dex-treated osteoblastic MC3T3-E1 cells. H2S donor NaHS as well as the CBS activator S-adenosyl-l-methionine (SAM) inhibited Dex-induced viability reduction, death and apoptosis in MC3T3-E1 cells. NaHS activated adenosine monophosphate (AMP)-activated protein kinase (AMPK) signaling, which participated its cyto-protective activity. AMPK inhibition by its inhibitor (compound C) or reduction by targeted-shRNA suppressed its pro-survival activity against Dex in MC3T3-E1 cells. Further, we found that NaHS inhibited Dex-mediated reactive oxygen species (ROS) production and ATP depletion. Such effects by NaHS were again inhibited by compound C and AMPKα1-shRNA. In summary, we show that H2S inhibits Dex-induced osteoblast damage through activation of AMPK signaling. H2S signaling might be further investigated as a novel target for anti-osteoporosis treatment.

Phosphorylation of mTOR and S6RP predicts the efficacy of everolimus in patients with metastatic renal cell carcinoma

Background

The incidence of renal cell cancer (RCC) has been increasing for the past decade, and the 5-year survival for patients with metastatic RCC (mRCC) is rather low. Everolimus (RAD001), a new inhibitor for mammalian target of rapamycin (mTOR), is generally well tolerated, and demonstrates clinical benefit to patients with anti-VEGF-refractory mRCC. However, factors for selection of patients who may benefit from everolimus remain largely unknown. Here we aimed to explore potential molecular indicators for mRCC patients who may benefit from everolimus treatment.

Methods

Paraffin-embedded tumor tissue specimens derived from 18 mRCC patients before everolimus treatment, who participated the phase 1b trial of everolimus in VEGF receptor (VEGFR)-tyrosine kinase inhibitor (TKI)-refractory Chinese patients with mRCC (clinicaltrials.gov, NCT01152801), were examined for the expression levels of phosphorylated AKT, mTOR, eukaryotic initiation factor 4E (eIF4E) binding protein-1 (4EBP1) and 40S ribosomal protein S6 (S6RP) by immunohistochemistry. Clinical benefit rate (complete response [CR], partial response [PR], plus stable disease [SD] ≥ 6 months) and progression-free survival time (PFS) were correlated with expression levels of these mTOR-associated molecules.

Results

In these 18 patients, there were 1 PR, 15 SDs (including 9 SDs ≥ 6 months), and 2 progressive diseases (PD). The clinical benefit rate (CBR) was 55.6% (10/18), and the median PFS time was 8.4 months. Patients with positive expression of phospho-mTOR showed a better CBR (71.4% versus 0%, P = 0.023) and PFS time (11.3 versus 3.7 months, P = 0.001) than those patients with negative expression. The median PFS of patients with positive phospho-S6RP expression was longer (11.3 versus 3.7 months, P = 0.002) than that of patients negative for phospho-S6RP expression. However, expression levels of phospho-4EBP1 and phospho-AKT were unassociated to efficacy of everolimus treatment with respect to CBR and PFS. Co-expression of phosphorylated mTOR, S6RP and/or 4EBP1 may improve the predictive value of the biomarkers for patients treated with everolimus.

Conclusions

The expression levels of phospho-mTOR and phospho-S6RP may be potential predictive biomarkers for efficacy of everolimus in patients with mRCC. Combining examinations of phosphorylated mTOR, S6RP and/or 4EBP1 may be a potential strategy to select mRCC patients sensitive to mTOR inhibitor treatment.

Tumor genetic analyses of patients with metastatic renal cell carcinoma and extended benefit from mTOR inhibitor therapy

PURPOSE

Rapalogs are allosteric mTOR inhibitors and approved agents for advanced kidney cancer. Reports of clonal heterogeneity in this disease challenge the concept of targeted monotherapy, yet a small subset of patients derives extended benefit. Our aim was to analyze such outliers and explore the genomic background of extreme rapalog sensitivity in the context of intratumor heterogeneity.

EXPERIMENTAL DESIGN

We analyzed archived tumor tissue of 5 patients with renal cell carcinoma, who previously achieved durable disease control with rapalogs (median duration, 28 months). DNA was extracted from spatially separate areas of primary tumors and metastases. Custom target capture and ultradeep sequencing was used to identify alterations across 230 target genes. Whole-exome sequence analysis was added to investigate genes beyond this original target list.

RESULTS

Five long-term responders contributed 14 specimens to explore clonal heterogeneity. Genomic alterations with activating effect on mTOR signaling were detected in 11 of 14 specimens, offering plausible explanation for exceptional treatment response through alterations in two genes (TSC1 and MTOR). In two subjects, distinct yet functionally convergent alterations activated the mTOR pathway in spatially separate sites. In 1 patient, concurrent genomic events occurred in two separate pathway components across different tumor regions.

CONCLUSIONS

Analysis of outlier cases can facilitate identification of potential biomarkers for targeted agents, and we implicate two genes as candidates for further study in this class of drugs. The previously reported phenomenon of clonal convergence can occur within a targetable pathway which might have implications for biomarker development beyond this disease and this class of agents.

Molecular alterations of PI3K/Akt/mTOR pathway: a therapeutic target in endometrial cancer

It is well established that the PI3K/Akt/mTOR pathway plays a central role in cell growth and proliferation. It has also been suggested that its deregulation is associated with cancer. Genetic alterations, involving components of this pathway, are often encountered in endometrial cancers. Understanding and identifying the rate-limiting steps of this pathway would be crucial for the development of novel therapies against endometrial cancer. This paper reviews alterations in the PI3K/Akt pathway, which could possibly contribute to the development of endometrial cancer. In addition, potential therapeutic targets of this pathway with emphasis on the mTOR inhibitors are also presented.

Hematologic toxicities associated with mTOR inhibitors temsirolimus and everolimus in cancer patients: a systematic review and meta-analysis

BACKGROUND

Mammalian target of rapamycin (mTOR) inhibitors, temsirolimus and everolimus, are currently approved for the treatment of several malignancies. Hematological toxicities have been reported with these drugs, but overall incidence and relative risk remains undefined. We perform an up-to-date meta-analysis to determine the incidence and risk of hematologic toxicities associated with mTOR inhibitors.

METHODS

Several databases were searched, including PubMed, Embase and Cochrane databases. Eligible studies included prospective phase II and III trials of temsirolimus and everolimus with adequate safety data profile reporting anemia, leucopenia, neutropenia or thrombocytopenia. Overall incidence rates, relative risk (RR), and 95% confidence intervals (CI) were calculated by using either random effects or fixed effects models according to the heterogeneity of included studies.

RESULTS

A total of 5436 patients with a variety of solid tumors from 26 clinical trials were included for the meta-analysis. The overall incidences of mTOR inhibitor associated all-grade and high-grade hematologic toxicities were, respectively: anemia--38.8% and 7.5%; leucopenia--19.6% and 1.8%; neutropenia--14.9% and 5.6%; thrombocytopenia--33.1% and 3.6%. Compared to placebo/control arms, mTOR inhibitors were associated with a significantly increased risk of all-grade (RR 2.05, 95% CI: 1.52-2.77; p < 0.001) and high-grade anemia (RR 1.57, 95% CI: 1.20-2.05; p = 0.001), all-grade (RR 6.03, 95% CI: 2.76-13.14; p < 0.001) and high-grade thrombocytopenia (RR 2.73, 95% CI: 1.87-3.99; p < 0.001). Additionally, a non-significantly increased risk of all-grade leucopenia (RR 1.46, 95% CI: 0.66-3.23; p = 0.34) and neutropenia (RR 1.77, 95% CI: 0.80-3.93; p = 0.16) was observed in the mTOR inhibitor group, while the risk of high-grade leucopenia (RR 0.53, 95% CI: 0.31-0.90, p = 0.019) and neutropenia (RR 0.96, 95% CI: 0.62-1.51; p = 0.87) did not increase. Similar results were also observed in sub-group analysis according to mTOR inhibitor based regimens.

CONCLUSIONS

The use of mTOR inhibitors is associated with a significant increase in the risk of developing all-grade and high-grade anemia and thrombocytopenia compared with placebo/control arms.

Clinical prognostic factors associated with outcome in patients with renal cell cancer with prior tyrosine kinase inhibitors or immunotherapy treated with everolimus

BACKGROUND

The mTOR inhibitor, everolimus, is approved for the treatment of metastatic renal cell carcinoma (RCC). However, prognostic models are needed to determine the patients who would most benefit from this therapy. We have developed a model based on clinical parameters and patient stratification into risk groups to predict patients with RCC who will derive the most benefit from treatment with everolimus.

METHODS

We assessed retrospective data on 57 patients with RCC who received everolimus after previous treatment with immunotherapy or tyrosine kinase inhibitors to identify prognostic factors for progression-free survival (PFS) and overall survival (OS). In the original phase II study, patients received 10mg of everolimus daily without interruption and were assessed every other week for the first 8 weeks on therapy and every 4 weeks thereafter. Kaplan-Meier analysis was used to calculate OS and PFS. Univariate and multivariate analyses were constructed using the Cox proportional hazards model and a stepwise procedure to validate the data.

RESULTS

We grouped patients according to risk: 0 prognostic factors indicated favorable risk, 1 to 2 factors intermediate risk, and≥3 factors poor risk. We found notable differences in median OS (29.6 mo for favorable risk, 14.3 mo for intermediate risk, and 7.2 mo for poor risk). Three risk factors (prior radiation treatment, no lung metastasis present at the start of treatment, and lymphocytes<25cells/µl) in the multivariate analysis were found to be associated with PFS, and 4 risk factors were found to be associated with OS (bone metastasis at start of treatment, LDH>1.5×upper limit of normal, alkaline phosphatase>120U/l, and lymphocytes<25cells/µl).

CONCLUSIONS

Our prognostic model includes 3 readily available clinical parameters for PFS and 4 readily available clinical parameters for OS to help stratify patients into poor, intermediate, and favorable prognosis groups for the treatment of everolimus in clear cell RCC. These intriguing results warrant further study in a larger patient population to validate the findings.

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.

New agents in renal cell carcinoma

Prior to 2005, the treatment options for metastatic renal cell carcinoma (mRCC) were limited. There has been a proliferation of agents since the introduction of sorafenib, sunitinib, and becavicumab for clinical use in advanced renal cell carcinoma. Recently, four new agents have been approved by the US Food and Drug Administration (FDA) for use in mRCC. These agents come from two unique targeted pathways for RCC, tyrosine kinase inhibitors (TKIs) of vascular endothelial growth factor (VEGF) and mammalian target of rapamycin (mTOR) inhibitors. This review examines the investigational evolution, phases of development, adverse event profiles, and future directions of pazopanib, axitinib, everolimus, and temsirolimus as well as new novel agents being explored in clinical trials for these targeted pathways.

Differentiating mTOR inhibitors in renal cell carcinoma

PI3K/Akt/mTOR signalling is dysregulated in many cancers, including renal cell carcinoma (RCC), and activation of this pathway has been suggested to correlate with aggressive behavior and poor prognosis in RCC tumors. mTOR inhibition plays a principal role in the targeted treatment of many cancer types, including RCC. Although mTOR inhibitors share the same mechanism of action, differences in metabolism, formulation and dosing schedule underpin distinct PK/PD profiles such that they may be differentiated for use in a variety of treatment niches. Approved mTOR inhibitors temsirolimus and everolimus serve as important therapeutic options within the current RCC treatment paradigm, although their recommended applications differ in setting and patient population characteristics. Clinical practice guidelines recommend temsirolimus for use in treatment-naive patients with poor-prognosis metastatic RCC of any histology (predominant clear cell or non-clear cell histology). Everolimus provides a standard-of-care therapy for patients with metastatic RCC whose disease has progressed after previous vascular endothelial growth factor receptor-tyrosine kinase inhibitor therapy. As therapeutic failure impacts the vast majority of patients with RCC, sequencing strategies of available agents or simultaneous targeting of multiple members of the PI3K/Akt/mTOR pathway may provide additional clinical benefit. Various classes of agents targeting the PI3K/Akt/mTOR pathway are currently being investigated, including mTORC1/mTORC2 kinase domain inhibitors, mTOR/PI3K dual inhibitors, PI3K-selective inhibitors, and programmed cell death 6 modulators. Clinical trials of mTOR inhibitors in a variety of tumor types are ongoing, and the role of mTOR inhibitors continues to evolve across the RCC treatment landscape.

Phase I study of panobinostat plus everolimus in patients with relapsed or refractory lymphoma

PURPOSE

To evaluate the safety and efficacy of panobinostat plus everolimus in patients with relapsed Hodgkin and non-Hodgkin lymphoma. The concept was supported by the single-agent clinical activity of histone deacetylase inhibitors and mTOR inhibitors, and on the in vitro mechanism-based synergistic antiproliferative activity.

EXPERIMENTAL DESIGN

This was a phase I study in patients with relapsed or refractory Hodgkin and non-Hodgkin lymphoma using panobinostat orally on Monday/Wednesday/Friday and everolimus orally daily. Toxicity and responses were assessed in dose-escalation cohort followed by expansion cohort at maximum-tolerated dose. Exploratory analysis of serum cytokine levels was performed.

RESULTS

Thirty patients were enrolled onto four dose levels. The dose-limiting toxicity was thrombocytopenia. The maximal tolerated dose was panobinostat 20 mg and everolimus 10 mg. Grade 3/4 toxicity included thrombocytopenia (64%), neutropenia (47%), anemia (20%), infection (10%), fatigue (7%), and dyspnea (7%). A total of 10 patients (33%; indolent lymphoma, T-cell lymphoma, mantle cell lymphoma, and Hodgkin lymphoma) achieved objective responses. In patients with Hodgkin lymphoma (n = 14), the overall response rate was 43% with complete response rate of 15%. In patients with Hodgkin lymphoma, multiple serum cytokine levels decreased significantly after treatment with this combination therapy. Of note, clinical responses were associated with a decrease in serum interleukin-5 levels (day 8, P = 0.013, and day 15, P = 0.021).

CONCLUSIONS

Our data suggest that the combination therapy is active but with significant thrombocytopenia. Future studies should explore alternate scheduling and different compounds that target the same pathways to improve the tolerability of this novel combination.

Alterations of Hypoxia-Induced Factor Signaling Pathway Due to Mammalian Target of Rapamycin (mTOR) Suppression in Ovarian Clear Cell Adenocarcinoma: In Vivo and in Vitro Explorations for Clinical Trial

Objectives

Before setting into the clinical trial using a combination of mammalian target of rapamycin (mTOR) inhibitors (rapamycin and everolimus) and other anticancer drugs, this study was conducted to confirm the efficacy of the new therapeutic strategy for ovarian clear cell adenocarcinoma (CCA), which targeted mTOR–hypoxia-induced factor (HIF) signal transduction system.

Materials and Methods

Using the cultured cells of CCA and animal models, alteration of mTOR-HIF cofactors and cell proliferation under the mTOR inhibitor–treated condition were analyzed.

Results

Mammalian target of rapamycin–HIF cofactors were inhibited dependent on concentration by mTOR inhibitor, resulting in suppression of the cultured CCA proliferation. However, von Hippel-Lindau was up-regulated at the messenger RNA level. In the nude mice with subcutaneously implanted CCA cells, apoptosis and necrosis were detected especially around the center of the tumors in the mTOR inhibitor–treated group more conspicuously than in the nontreated group. In the assessment of combination therapy with other antitumor agents, a combined treatment with mTOR inhibitor and chemotherapeutic agents caused a significant decrease in tumor size compared to the chemotherapeutic agents–only group.

Conclusions

Treatment by mTOR inhibitor is expected to down-regulate the cell proliferation of the CCA as a new therapeutic strategy.

Pulmonary complications with the use of mTOR inhibitors in targeted cancer therapy: a systematic review and meta-analysis

Mammalian target of rapamycin (mTOR) inhibitors have gained regulatory approval for use in several cancer types. Pulmonary adverse events associated with mTOR inhibitors are well recognized but their frequency has varied considerably among trials. PubMed and ASCO abstracts were searched to identify clinical trials of mTOR inhibitors in solid tumors. Twenty-two eligible trials on which 4,242 patients were treated met the criteria for inclusion in this systematic review and meta-analysis. Adverse event data were extracted and used to determine the incidence rate and incidence rate ratio for pneumonitis, dyspnea, and cough. The incidence rate of any grade pneumonitis in patients with solid tumors treated with mTOR inhibitors was 0.11 (95% confidence interval (CI), 0.06-0.17) per patient, while the incidence of grade 3-4 pneumonitis was 0.03 (95% CI, 0.01-0.04) per patient. The incidence rate ratio (IRR) of any grade pneumonitis with mTOR inhibitors relative to controls was 19.0 (95% CI, 6.5-55.4), and for grade 3-4 pneumonitis was 8.0 (95% CI, 2.6-24.1). The incidence rate for any grade and grade 3-4 cough was 0.23 (95% CI, 0.20-0.27) per patient and 0.01 (95% CI, 0.00-0.01) per patient, respectively. The incidence rate for any grade and grade 3-4 dyspnea was 0.15 (95% CI, 0.10-0.21) per patient and 0.03 (95% CI, 0.02-0.04) per patient, respectively. Compared to control, treatment with mTOR inhibitors were associated with a significant increase in any grade cough [IRR = 1.9 (95% CI, 1.6-2.4)] and grade 3-4 dyspnea [IRR = 2.0 (95% CI, 1.2-3.3)]. This study provides an estimation of the risk of pulmonary adverse events in solid tumor patients treated with mTOR inhibitors. While pulmonary adverse events are relatively common with mTOR inhibitors, most are low grade and asymptomatic.

Cancer in the transplant recipient

Malignancy has become one of the three major causes of death after transplantation in the past decade and is thus increasingly important in all organ transplant programs. Death from cardiovascular disease and infection are both decreasing in frequency from a combination of screening, prophylaxis, aggressive risk factor management, and interventional therapies. Cancer, on the other hand, is poorly and expensively screened for; risk factors are mostly elusive and/or hard to impact on except for the use of immunosuppression itself; and finally therapeutic approaches to the transplant recipient with cancer are often nihilistic. This article provides a review of each of the issues as they come to affect transplantation: cancer before wait-listing, cancer transmission from the donor, cancer after transplantation, outcomes of transplant recipients after a diagnosis of cancer, and the role of screening and therapy in reducing the impact of cancer in transplant recipients.

mTOR kinase inhibitors as potential cancer therapeutic drugs

The mammalian target of rapamycin (mTOR) plays a critical role in the positive regulation of cell growth and survival primarily through direct interaction with raptor (forming mTORC complex 1; mTORC1) or rictor (forming mTOR complex 2; mTORC2). The mTOR axis is often activated in many types of cancer and thus has become an attractive cancer therapeutic target. The modest clinical anticancer activity of conventional mTOR allosteric inhibitors, rapamycin and its analogs (rapalogs), which preferentially inhibit mTORC1, in most types of cancer, has encouraged great efforts to develop mTOR kinase inhibitors (TORKinibs) that inhibit both mTORC1 and mTORC2, in the hope of developing a novel generation of mTOR inhibitors with better therapeutic efficacy than rapalogs. Several TORKinibs have been developed and actively studied pre-clinically and clinically. This review will highlight recent advances in the development and research of TORKinibs and discuss some potential issues or challenges in this area.

Recent advances in the treatment of metastatic renal cell carcinoma

In the past 5 years, the treatment of patients with metastatic renal cell carcinoma has changed dramatically from being largely cytokine-based with the emergence of targeted therapy. Following the elucidation of various molecular pathways in renal cell carcinoma, targeted agents (particularly vascular endothelial growth factor-targeting antiangiogenic agents) now form the backbone of most therapeutic strategies for patients with metastatic renal cell carcinoma and the outcome of treatment has improved. However, many tumors eventually develop resistance to targeted therapy due to secondary mutation of the target protein or compensatory changes within the target pathway that bypass the site of inhibition. On the other hand, there are new forms of immunotherapy that hold the promise of improving the outcome for patients with metastatic renal cell carcinoma. In this article, we describe some of these new therapies, including the anti-vascular endothelial growth factor monoclonal antibody bevacizumab, several receptor tyrosine kinase inhibitors (sorafenib, sunitinib, pazopanib, axitinib, and tivozanib), the mammalian target of rapamycin inhibitors temsirolimus and everolimus, and new immunotherapy modalities, such as anti-cytotoxic T-lymphocyte-associated antigen 4 antibody and anti-programmed cell death 1/programmed cell death-ligand 1 antibody. We also discuss their role in the current management of patients with metastatic renal cell carcinoma.

Metabolic complications with the use of mTOR inhibitors for cancer therapy

BACKGROUND

mTOR inhibitors are now approved by regulatory agencies for the treatment of a variety of malignancies. The risk of metabolic complications with these agents is not well characterized.

METHODS

PubMed was searched for articles published from 2001 until 2011. Eligible studies included prospective randomized trials evaluating temsirolimus, everolimus, and ridaforolimus in patients with all solid tumor malignancies. Sixteen eligible phase II clinical trials and 8 randomized controlled clinical trials were included in a systematic review and meta-analysis and the number of metabolic related AEs (hyperglycemia, hypercholesterolemia, and hypertriglyceridemia) was extracted. Incidence rates and incident rate ratios were calculated.

FINDINGS

Twenty-four trials, including 4261 patients, were included in the calculation of the incidence rate. The average incidence rate of all grade metabolic related events was 0.70 (95% CI, 0.47, 0.93). The average incidence rate of serious (grade 3 and 4) metabolic related adverse events was 0.11 (95% CI, 0.08, 0.15). The incidence rate ratio (IRR) of a metabolic adverse event with mTOR inhibitor therapy compared with control was 2.93 (95% CI, 2.33, 3.70) and of serious grade 3 and 4 metabolic adverse events was 4.58 (95% CI, 2.86, 7.34). The IRR of all grade hyperglycemia was 2.95 (95% CI, 2.14, 4.05) and of grade 3-4 hyperglycemia was 5.25 (95% CI, 3.07, 9.00). The IRR of all grade hypertriglyceridemia was 2.49 (95% CI, 1.76, 3.52) and of grade 3-4 hypertriglyceridemia was 2.01 (95% CI, 0.65, 6.27). The IRR of all grade hypercholesterolemia was 3.35 (95% CI, 2.17, 5.18) and of grade 3-4 hypercholesterolemia was 6.51 (95% CI, 1.48, 28.59). These findings suggest a statistically significant increase in the risk of hyperglycemia, hypercholesterolemia (all grades and grade 3 and 4), and all grade hypertriglyceridemia associated with mTOR therapy when compared with control.

INTERPRETATION

The risk of all grade and grade 3-4, hyperglycemia, hypercholesterolemia, and hypertriglyceridemia, are increase in patients treated with mTOR inhibitors compared with control.

Safety and efficacy of everolimus in Chinese patients with metastatic renal cell carcinoma resistant to vascular endothelial growth factor receptor-tyrosine kinase inhibitor therapy: an open-label phase 1b study

BACKGROUND

In China, there are currently no approved therapies for the treatment of metastatic renal cell carcinoma (mRCC) following progression with vascular endothelial growth factor (VEGF)-targeted agents. In the phase 3 RECORD-1 trial, the mammalian target of rapamycin (mTOR) inhibitor everolimus afforded clinical benefit with good tolerability in Western patients with mRCC whose disease had progressed despite VEGF receptor-tyrosine kinase inhibitor (VEGFr-TKI) therapy. This phase 1b study was designed to further evaluate the safety and efficacy of everolimus in VEGFr-TKI-refractory Chinese patients with mRCC.

METHODS

An open-label, multicenter phase 1b study enrolled Chinese patients with mRCC who were intolerant to, or progressed on, previous VEGFr-TKI therapy (N = 64). Patients received everolimus 10 mg daily until objective tumor progression (according to RECIST, version 1.0), unacceptable toxicity, death, or study discontinuation for any other reason. The final data analysis cut-off date was November 30, 2011.

RESULTS

A total of 64 patients were included in the study. Median age was 52 years (range, 19-75 years) and 69% of patients were male. Median duration of everolimus therapy was 4.1 months (range, 0.0-16.1 months). Expected known class-effect toxicities related to mTOR inhibitor therapy were observed, including anemia (64%), hypertriglyceridemia (55%), mouth ulceration (53%), hyperglycemia (52%), hypercholesterolemia (50%), and pulmonary events (31%). Common grade 3/4 adverse events were anemia (20%), hyperglycemia (13%), increased gamma-glutamyltransferase (11%), hyponatremia (8%), dyspnea (8%), hypertriglyceridemia (6%), and lymphopenia (6%). Median PFS was 6.9 months (95% CI, 3.7-12.5 months) and the overall tumor response rate was 5% (95% CI, 1-13%). The majority of patients (61%) had stable disease as their best overall tumor response.

CONCLUSIONS

Safety and efficacy results were comparable to those of the RECORD-1 trial. Everolimus is generally well tolerated and provides clinical benefit to Chinese patients with anti-VEGF-refractory mRCC.

TRIAL REGISTRATION

clinicaltrials.gov, NCT01152801.

mTOR inhibitors in advanced renal cell carcinomas: from biology to clinical practice

To date, oral everolimus is indicated for the treatment of patients with advanced renal cell carcinoma, whose disease has progressed on or after treatment with vascular endothelial growth factor-targeted therapy, and intravenous temsirolimus for the first-line treatment of patients with poor prognosis metastatic renal cell carcinoma. However, some factors could guide the treatment choice aiming to individualize a treatment plan. Besides the crucial issue of treatment efficacy, other factors are to be considered such as disease status, histological subtype, extent of the disease, patient-specific factors, and agent-specific factors. All of these considerations have to stay in the frame of guideline recommendations which represent evidence-based medicine. The purpose of this article is to summarize the main pharmacological and pharmacokinetic characteristics of mTOR inhibitors, and to define targeted populations according to prognostic indexes.

Impact of genetic alterations on mTOR-targeted cancer therapy

Rapamycin and its derivatives (rapalogs), a group of allosteric inhibitors of mammalian target of rapamycin (mTOR), have been actively tested in a variety of cancer clinical trials, and some have been approved by the Food and Drug Administration for the treatment of certain types of cancers. However, the single agent activity of these compounds in many tumor types remains modest. The mTOR axis is regulated by multiple upstream signaling pathways. Because the genes (e.g., PIK3CA, KRAS, PTEN, and LKB1) that encode key components in these signaling pathways are frequently mutated in human cancers, a subset of cancer types may be addicted to a given mutation, leading to hyperactivation of the mTOR axis. Thus, efforts have been made to demonstrate the potential impact of genetic alterations on rapalog-based or mTOR-targeted cancer therapy. This review will primarily summarize research advances in this direction.

Detection of rapalog-mediated therapeutic response in renal cancer xenografts using ⁶⁴Cu-bevacizumab immunoPET

The importance of neovascularization for primary and metastatic tumor growth fostered numerous clinical trials of angiogenesis inhibitors either alone or in combination with conventional antineoplastic therapies. One challenge with the use of molecularly targeted agents has been the disconnection between size reduction and tumor biologic behavior, either when the drug is efficacious or when tumor resistance emerges. Here, we report the synthesis and characterization of (64)Cu-NOTA-bevacizumab as a PET imaging agent for imaging intratumoral VEGF content in vivo. (64)Cu-NOTA-bevacizumab avidly accumulated in 786-O renal carcinoma xenografts with lower levels in host organs. RAD001 (everolimus) markedly attenuated (64)Cu-NOTA-bevacizumab accumulation within 786-O renal carcinoma xenografts. Tumor tissue and cellular molecular analysis validated PET imaging, demonstrating decreases in total and secreted VEGF content and VEGFR2 activation. Notably, (64)Cu-NOTA-bevacizumab PET imaging was concordant with the growth arrest of RAD001 tumors. These data suggest that immunoPET targeting of angiogenic factors such as VEGF could be a new class of surrogate markers complementing the RECIST criteria in patients receiving molecularly targeted therapies.

Everolimus in metastatic renal cell carcinoma after failure of initial vascular endothelial growth factor receptor-tyrosine kinase inhibitor (VEGFr-TKI) therapy: results of an interim analysis of a non-interventional study

BACKGROUND

Everolimus is approved for treatment of anti-vascular endothelial growth factor (VEGF)-refractory patients with metastatic renal cell carcinoma (mRCC). Clinical trials rarely mirror treatment reality. Thus, a broader evaluation of everolimus is valuable for routine use.

PATIENTS AND METHODS

A German multicenter non-interventional study documented mRCC patients starting everolimus after failure of initial VEGF-targeted therapy. Primary endpoint was effectiveness, defined as time to progression (TTP) according to investigator assessment (time from first dose to progression).

RESULTS

Of 382 documented patients, 196 were included in this interim analysis. In the efficacy population (n = 165), median TTP was 7.0 months (95% confidence interval (CI) 5.1-9.0). Among patients with < or ≥ 6 months of previous VEGF-targeted therapy, median TTP was 6.6 months (95% CI 3.8-not estimable) and 7.4 months (95% CI 4.6-9.6), respectively. Most common adverse events were anemia (13%) and dyspnea (14%). Physicians assessed high tolerance and documented high adherence to everolimus therapy (approximately 97%).

CONCLUSION

In routine clinical practice, everolimus is effective, as measured by median TTP (longer than median progression-free survival in RECORD-1 trial), and well tolerated. Our results support everolimus use in anti-VEGF-refractory patients with mRCC.

A review of oral toxicity associated with mTOR inhibitor therapy in cancer patients

Aphthous-like stomatitis has been identified as one of the most common dose-limiting toxicities associated with mTOR inhibitor therapy in cancer patients. The objective of this study was to summarize the cumulative oral toxicities associated with mTOR inhibitors in published oncology trials with respect to dose, schedule, and need for dose modifications. A review of all oncology-related clinical trials of mTOR inhibitors was conducted and standardized data was abstracted from each study. 44 studies were included in the analysis with a total of 2822 patients treated with temsirolimus (19 studies), everolimus (20 studies), and ridaforolimus (five studies) for a wide range of malignancies. At least one adverse event (AE) occurred in 74.4% of patients. Mucositis was the most frequent AE overall (73.4%), the third most frequent severe AE (20.7%), accounting for 27.3% dose reductions and 13.1% of discontinuations, and the most frequent dose limiting toxicity (52.5%). Mucositis typically occurred during the first cycle of therapy and was graded as mild to moderate in approximately 90% of the patients; severe mucositis generally occurred at higher doses. There were no clear differences in mucositis among the three agents and in most cases lesions resolved spontaneously. Oral mucositis is a frequent complication of mTOR inhibitor therapy and a significant cause of dose reductions and discontinuations in oncology trials. Prevention and management strategies should be investigated to improve tolerability and better permit effective long-term regimens.

Incidence and management of mTOR inhibitor-associated pneumonitis in patients with metastatic renal cell carcinoma

The administration of mammalian target of rapamycin (mTOR) inhibitors can give rise to a potentially life-threatening adverse event, often referred to as 'non-infectious pneumonitis' (NIP), which is characterized by non-infectious, non-malignant, and non-specific inflammatory infiltrates. Patients usually present with cough and/or dyspnoea. We provide a brief description of the mechanism of action of mTOR inhibitors and their overall safety in patients with metastatic renal cell carcinoma (mRCC) and review the literature on mTOR inhibitor-associated NIP in patients with solid tumours. The review was used to derive questions on the diagnosis, management, and monitoring of mRCC patients with NIP, and to develop a decision tree for use in routine clinical practise. A key recommendation was the subdivision of grade 2 NIP into grades 2a and 2b, where grade 2a is closer to grade 1 and grade 2b to grade 3. This subdivision is important because it takes into account the nature and severity of clinical symptoms potentially related to NIP, either the onset of new symptoms or the worsening of existing symptoms, and thus determines the type and frequency of follow-up. It also helps to identify a subgroup of patients in whom treatment, if effective, may be continued without dose adjustment.

Dynamic tumor modeling of the dose-response relationship for everolimus in metastatic renal cell carcinoma using data from the phase 3 RECORD-1 trial

Background

The phase 3 RECORD-1 trial (NCT00410124) established the efficacy and safety of everolimus in patients with metastatic renal cell carcinoma (mRCC) who progress on sunitinib or sorafenib. In RECORD-1, patients received 10 mg everolimus daily, with dose reduction to 5 mg daily allowed for toxicity. We have developed a model of tumor growth dynamics utilizing serial measurements of the sum of the longest tumor diameters (SLD) from individual RECORD-1 patients to define the dose–response relationship of everolimus.

Results

The model predicts that after 1 year of continuous dosing, the change in SLD of target lesions will be +142.1% ± 98.3%, +22.4% ± 17.2%, and –15.7% ± 11.5% in the average patient treated with placebo, 5 mg everolimus, and 10 mg everolimus, respectively. This nonlinear, mixed-effects modeling approach can be used to describe the dynamics of each individual patient, as well as the overall population. This allows evaluation of how an actual dosing history and individual covariates impact on the observed drug effect, and offers the possibility of predicting clinical observations as a function of time.

Conclusions

In this pharmacodynamic model of tumor response, everolimus more effectively shrinks target lesions in mRCC when dosed 10 mg daily versus 5 mg daily, although a 5-mg dose still shows an antitumor effect. These data support earlier studies that established 10 mg daily as the preferred clinical dose of everolimus, and improve our understanding of the everolimus dose–response relationship.

Axitinib for the treatment of patients with advanced metastatic renal cell carcinoma (mRCC) after failure of prior systemic treatment

The landscape of renal cell carcinoma (RCC) treatment has changed dramatically during recent years. Bevacizumab/interferon, sunitinib, sorafenib, temsirolimus, everolimus, and pazopanib have been proven effective in metastatic RCC. Axitinib is a novel tyrosine kinase inhibitor, which inhibits the vascular endothelial growth factor receptor (VEGFR) at subnanomolar level. Based on this extraordinary VEGFR inhibition, axitinib is considered a next-generation agent. The recent AXIS trial reported on axitinib's efficacy in second line treatment of RCC, which led to its recent approval in the USA. This review focuses on the clinical efficacy of axitinib in RCC patients.

mTOR inhibitors and its role in the treatment of head and neck squamous cell carcinoma

OPINION STATEMENT

Head and neck squamous cell carcinomas (HNSCC) represent 6% of all cancers diagnosed each year in the United States, affecting approximately 43,000 new patients and resulting in approximately 12,000 deaths. Currently, three main rapalogs exist for the treatment of cancer: CCI-779 (temsirolimus), RAD001 (everolimus), and AP235373 (deforolimus). Clinicians managing HNSCC need to be aware of the three rapalogs. Extensive evidence has shown rapamycin-analogs to be effective agents in the treatment of a number of solid tumors. While extensive preclinical data suggests that HNSCC would be an appropriate tumor type to benefit from inhibition of the mTOR pathway, limited clinical data is yet available to support this. Numerous phase II trials evaluating mTOR inhibitors for use in HNSCC are currently recruiting patients.

Current status of targeted therapy for advanced renal cell carcinoma

The treatment of metastatic renal cell carcinoma (mRCC) has recently evolved from being predominantly cytokine-based treatment to the use of targeted agents, which include sorafenib, sunitinib, bevacizumab (plus interferon alpha [IFN-α]), temsirolimus, everolimus, pazopanib, and most recently, axitinib. Improved understanding of the molecular pathways implicated in the pathogenesis of RCC has led to the development of specific targeted therapies for treating the disease. In Korea, it has been 5 years since targeted therapy became available for mRCC. Thus, we now have broader and better therapeutic options at hand, leading to a significantly improved prognosis for patients with mRCC. However, the treatment of mRCC remains a challenge and a major health problem. Many questions remain on the efficacy of combination treatments and on the best methods for achieving complete remission. Additional studies are needed to optimize the use of these agents by identifying those patients who would most benefit and by elucidating the best means of delivering these agents, either in combination or as sequential single agents. Furthermore, numerous ongoing research activities aim at improving the benefits of the new compounds in the metastatic situation or their application in the early phase of the disease. This review introduces what is currently known regarding the fundamental biology that underlies clear cell RCC, summarizes the clinical evidence supporting the benefits of targeted agents in mRCC treatment, discusses survival endpoints used in pivotal clinical trials, and outlines future research directions.

Patterns of interstitial lung disease during everolimus treatment in patients with metastatic renal cell carcinoma

OBJECTIVE

To elucidate the patterns of interstitial lung disease during everolimus treatment in patients with metastatic renal cell carcinoma, we reviewed seven cases of everolimus-induced interstitial lung disease.

METHODS

Seven patients with metastatic renal cell carcinoma, which continued to progress despite treatment with sunitinib or sorafenib, developed interstitial lung disease after treatment with everolimus.

RESULTS

Chest X-ray demonstrated diffuse infiltrates in lung fields, and chest computed tomography showed bilateral reticular and ground-glass opacities. Serum levels of lactate dehydrogenase (7/7), C-reactive protein (6/7), pulmonary surfactant associated protein D (1/7) and Krebs von den Lungen 6 (5/7) were elevated. The bronchoalveolar lavage fluid obtained from four patients with Grade 3 interstitial lung disease showed lymphocytosis. The transbronchial lung biopsy specimens showed interstitial lymphocytic infiltration and septal thickening of alveolar walls. In two cases with mild interstitial lung disease, the everolimus therapy was successfully continued. In four cases with Grade 3 interstitial lung disease, the drug was discontinued and steroid therapy was initiated. Pulmonary symptoms and radiological abnormalities resolved within 2 months.

CONCLUSIONS

Serum Krebs von den Lungen 6 was elevated compared with baseline in all cases with interstitial lung disease. Some patients who developed mild interstitial lung disease during everolimus treatment could continue to receive the treatment. Even when severe interstitial lung disease developed, withdrawal of the drug and short-term use of high-dose steroids resulted in rapid recovery. Prompt recognition of interstitial lung disease exacerbation as well as exclusion of progressive disease or infection is of primary importance.