Sunitinib in patients with metastatic renal cell carcinoma

Metastatic Renal Cell Carcinoma: Many Treatment Options, One Patient

There has been a recent expansion of therapeutic options in metastatic renal cell carcinoma (RCC) targeted at the vascular endothelial growth factor and mammalian target of rapamycin pathways, which are fundamental to the biology of RCC. These treatment options have similarities in antitumor effect but also important differences in regards to clinical effects, toxicity and patient populations in which they have been investigated. Further, issues regarding the role of debulking nephrectomy, timing of therapy, and appropriate sequencing of agents have emerged as clinically relevant. There are thus potentially many different treatment approaches to each metastatic RCC patient. This review discusses how to integrate the available data regarding targeted therapy in metastatic RCC into personalized cancer care.

Treatment outcomes of sunitinib treatment in advanced renal cell carcinoma patients: a single cancer center experience in Korea

PURPOSE

The retrospective study was performed to assess the efficacy and toxicity profiles of sunitinib in Korean patients with metastatic renal cell carcinoma (RCC).

MATERIALS AND METHODS

Between January 2005 and December 2008, 76 Korean patients with recurrent/metastatic RCC who received sunitinib were retrospectively reviewed. The primary end point was progression-free survival and the secondary end points were overall survival and response rate. We also assessed the toxicities associated with sunitinib treatment.

RESULTS

Of the 76 patients, 69 (90.1%) were diagnosed with clear cell RCC. The median progression-free survival and overall survival were 7.2 and 22.8 months, respectively in overall patients. Sixty-two patients (81.6%) received 50 mg 4 week and 2 week off schedule, and 14 patients (18.4%) received 37.5 mg daily on a daily continuous schedule. The objective response rate and disease control rate were 27.6% and 84.2%, respectively. A dose reduction or reduction in dose due to adverse events occurred in 76% of the patients, whereas 11% of the patients had discontinued treatment. Other common laboratory abnormalities were increased serum creatinine (75.6%), elevated alanine aminotransferase (71.0%), neutropenia (61.8%), anemia (69.7%), and increased aspartate aminotrasferase (53.3%). Grade 3/4 toxicities occurred as follows: thrombocytopenia (38.2%), fatigue (10.5%), stomatitis (10.5%), and hand-foot syndrome (9.2%).

CONCLUSION

Our results indicate that sunitinib treatment is effective and tolerable for ecurrent/metastatic RCC patients in Korea. Further studies with prognostic or biochemical factors are needed to clarify the different toxicity profiles of this study.

Vaccination of patients with metastatic renal cancer with modified vaccinia Ankara encoding the tumor antigen 5T4 (TroVax) given alongside interferon-alpha

Approximately 90% of renal cell tumors overexpress the tumor antigen 5T4. The attenuated strain of vaccinia virus, modified vaccinia Ankara, has been engineered to express 5T4 (TroVax). We conducted an open-label phase 1/2 trial in which TroVax was administered alongside interferon-alpha (IFNalpha) to 11 patients with metastatic renal cell carcinoma. Antigen-specific cellular and humoral responses were monitored throughout the study, and clinical responses were assessed by measuring the changes in tumor burden by computed tomography scan (Response Evaluation Criteria In Solid Tumors). The primary objective was to assess the safety, immunogenicity, and efficacy of TroVax when given alongside IFNalpha. Treatment with TroVax plus IFNalpha was well tolerated with no serious adverse events attributed to TroVax. All 11 patients mounted 5T4-specific antibody responses and 5 (45%) mounted cellular responses. No objective tumor responses were seen, but the overall median time to progression (TTP) of 9 months (range: 2.1 to 26+ mo) was longer than expected for IFNalpha alone. For the 10 clear cell patients the TTP ranged from 3.9 to 26+ months, with a median TTP of 10.4 months. The high frequency of 5T4-specific immune responses and prolonged median TTP for clear cell patients compared with that expected for IFNalpha alone is encouraging and warrants further investigation.

Advanced renal cell carcinoma: what to do after first line antiangiogenic therapy?

PURPOSE OF REVIEW

Antiangiogenic therapy is now a standard in first line for metastatic renal cell carcinoma. Among the different options, sunitinib is particularly proposed by most guidelines, as well as a combination of bevacizumab and interferon-alfa. Defining second line therapy after these agents is dependent on indirect data since no phase III trial has specifically addressed that question.

RECENT FINDINGS

The most relevant data point to everolimus that has been proven to improve PFS with acceptable toxicity compared with best supportive care in a phase III trial. Most studies on the use of antiangiogenic therapies after failure of a first one seem to demonstrate, more than anything else, that the most effective antiangiogenic therapy should be used up front since limited benefit is expected in second line.

SUMMARY

This paper presents some relevant data to help recommend the most appropriate second-line therapy. The quality of data on everolimus is sufficient to propose its use for most patients in the second line setting after failure of a vascular endothelial growth factor receptor-tyrosine kinase inhibitor (VEGFR-TKI). Studies on a second line of antiangiogenic therapy demonstrate limited efficacy that does not lead to a recommendation of adequacy for most patients.

VEGF induces expression of Bcl-2 and multiple signaling factors in microvascular endothelial cells in a prostate cancer model

PURPOSE

We have previously demonstrated that prostate tumors that highly express Bcl-2 are not only more tumorigenic, but also more angiogenic than low Bcl-2 expressing tumors. Observed increased rates of angiogenesis are likely due to the secretion of multiple factors from the tumor cells.

EXPERIMENTAL DESIGN

Human endothelial cells were subjected to exogenous VEGF or conditioned media from PC-3 cells and assayed by several in vitro systems to better characterize the effects of tumor microenvironment on endothelial cells.

RESULTS

VEGF stimulation increased Bcl-2 expression in human microvascular endothelial cells (HMVECs), at least partially through stabilization of Bcl-2 mRNA transcripts, and protected these cells from apoptosis. These effects were mimicked by treatment of HMVECs with conditioned media from cultured PC-3 prostate tumor cells manipulated to overexpress Bcl-2. Through the use of kinase inhibitors and molecular profiling, several distinct pathways were implicated in the regulation of Bcl-2 in HMVECs, including those involving PI3K/AKT, PKC, mTOR, STAT-1, and IL-8, factors associated with tumor survival and growth.

CONCLUSIONS

This study identifies molecular elements of a link between Bcl-2 expression in distinct cell types within a tumor and reaffirms that strategies designed to target Bcl-2 are desirable as they might enhance treatment response through dual effects.

Cardiac magnetic resonance imaging in sunitinib malate-related cardiomyopathy: no late gadolinium enhancement

Sunitinib malate, an oral multitargeted tyrosine kinase inhibitor (TKI), has been approved for the treatment of advanced renal cell carcinoma and gastrointestinal stromal tumors. It is supposed that this targeted approach improves antitumor activity with less toxicity than traditional chemotherapy. However, unanticipated cardiotoxicity related to TKIs has been reported. Less well described are the treatment and prognosis of patients with sunitinib-related cardiogenic shock. Here, we report a successfully treated case. In contrast to previous case reports, the shock status did not allow for standard heart failure treatment with angiotensin-converting enzyme inhibitor or beta-blocker. We used intra-aortic balloon counterpulsation, and the patient survived. Twenty-four days after onset, the patient's left ventricular ejection fraction had improved from 20% to 48%. To the best of our knowledge, this is the first case report of severe heart failure after sunitinib treatment in Taiwan. As the clinical application of TKIs expands, cardiologists and oncologists should be alert to the possible adverse cardiovascular effects and be ready to institute prompt treatment.

CSF1R copy number changes, point mutations, and RNA and protein overexpression in renal cell carcinomas

Renal cell carcinomas comprise a heterogeneous group of tumors. Of these, 80% are clear cell renal cell carcinomas, which are characterized by loss of 3p, often with concomitant gain of 5q22qter. Although VHL is considered the main target gene of the 3p deletions, none has been identified as the relevant target gene for the 5q gain. We have studied 75 consecutive kidney tumors and paired normal kidney samples to evaluate at the genomic and expression levels the tyrosine kinase genes CSF1R and PDGFRB as potential targets in this region. Our findings show that RNA expression of CSF1R, but not of PDGFRB, was significantly higher in clear cell renal cell carcinomas than in normal tissue samples, something that was corroborated at the protein level by immunohistochemistry. The CSF1R staining pattern in clear cell renal cell carcinomas was clearly different from that observed in other renal cell carcinomas, suggesting its potential usefulness in differential diagnosis. FISH analysis demonstrated whole chromosomal gain and relative CSF1R/PDGFRB copy number gain in clear cell renal cell carcinomas, which might contribute to CSF1R overexpression. Finally, one polymorphism and two novel mutations were identified in CSF1R in clear cell renal cell carcinoma patients. Our data allow us to conclude that CSF1R plays a relevant role in clear cell renal cell carcinoma carcinogenesis and raise the possibility that CSF1R may represent a future valuable therapeutic target in these patients.

The angiogenic switch in carcinogenesis

Coined in the late eighties, the term "angiogenic switch" refers to a time-restricted event during tumor progression where the balance between pro- and anti-angiogenic factors tilts towards a pro-angiogenic outcome, resulting in the transition from dormant avascularized hyperplasia to outgrowing vascularized tumor and eventually to malignant tumor progression. The molecular players and mechanisms underlying the angiogenic switch have been intensely investigated. In particular, a large number of pro-angiogenic factors and angiogenic inhibitors activated and repressed, respectively, in their activities during the angiogenic switch have been identified and characterized. Part of this research has lead to the development of various pro- and anti-angiogenic therapies that are currently tested in clinical trials or are already in clinical use. More recently, transgenic mouse models of cancer have been instrumental in revealing that inflammatory responses within the tumor microenvironment are critically contributing to the onset of tumor angiogenesis. These mouse models closely recapitulate multistage carcinogenesis in cancer patients and represent reliable tools to study the molecular and cellular players implicated in the onset and maintenance of tumor angiogenesis. Furthermore, they also offer the opportunity to assess the efficacy of novel anti-angiogenic cancer therapies and the nature of developing resistance mechanisms. These experiments have provided first important concepts to improve anti-angiogenic therapy and thus directly contribute to their translation to the clinical setting.

Multitarget drugs: the present and the future of cancer therapy

Target therapies for the treatment of human cancers have revolutionized the concept of oncological medicine. This type of therapeutic approach is directed to the inhibition of molecular targets that play a pivotal role in tumor progression -- such as tyrosine kinase receptors (TKIs) controlling cell proliferation and survival -- mainly by means of compounds able to block their activity. In the beginning, the aim of target therapies was specifically to hit a single molecule expressed in neoplastic cells. Now the prevailing idea is that inhibiting both cancer cells and cells of the stroma supporting the tumor would gain better results in fighting the disease. Therefore, the single-target therapy is fading in favor of a multitarget approach and the new generation of TKIs is selected on the basis of their ability simultaneously to target different molecules. This review summarizes the molecular basis of multitarget therapies and the most relevant results obtained in different cancer types.

Management of metastatic renal cell carcinoma: current trends

Renal cell carcinoma is one of the common malignancies of the genitourinary tract. In approximately one third of patients, distant metastases are present at the time of initial diagnosis and in another third, the tumor will recur even after nephrectomy with a curative intent. Renal cell carcinoma is resistant to all conventional treatment modalities of cancer, including radiotherapy and chemotherapy. We review the management of patients with metastatic renal cell carcinoma in the era of the new targeted therapeutic agents.

Innovations and challenges in renal cancer: summary statement from the Third Cambridge Conference

The Third Cambridge Conference on Innovations and Challenges in Renal Cancer, a symposium held in Cambridge, Massachusetts, June 27-28, 2008, and chaired by Michael B. Atkins, was convened to discuss the current state of knowledge in the field, critique new data, stimulate communication among those involved in basic and clinical research, and offer recommendations for further study. Four main topics were discussed: genetics and molecular biology of renal cell cancer, staging and prognosis, systemic therapy, and correlative science and biomarkers in stage IV disease. The conference format combined brief presentations with extended periods of discussion. The conclusions and recommendations are summarized in this paper and presented in more detail in the individual papers that follow.

Hereditary kidney cancer: unique opportunity for disease-based therapy

Kidney cancer is not a single disease; it is comprised of several different types of cancer, each with a different histology, with a different clinical course, caused by a different gene, and responding differently to therapy. The VHL gene is the gene for the hereditary cancer syndrome, von Hippel-Lindau, as well as for the common form of sporadic, noninherited, clear cell kidney cancer. Understanding the VHL-hypoxia inducible factor (HIF) pathway has provided the foundation for the development of several agents targeting this pathway, such as sunitinib, sorafenib, and temsirolimus. Hereditary papillary renal carcinoma (HPRC) is a hereditary renal cancer syndrome in which affected individuals are at risk for the development of bilateral, multifocal, type 1 papillary renal cell carcinoma. The genetic defect underlying HPRC is MET, the cell surface receptor for hepatocyte growth factor. Mutations of MET also have been identified in a subset of tumors from patients with sporadic type 1 papillary renal cell carcinoma (RCC). Clinical trials targeting the MET pathway are currently underway in patients with HPRC and in patients with sporadic (nonhereditary) papillary kidney cancer. The BHD gene (also known as folliculin or FLCN) is the gene for Birt-Hogg-Dube syndrome, an autosomal-dominant genodermatosis associated with a hereditary form of chromophobe and oncocytic, hybrid RCC. Preclinical studies are underway targeting the BHD gene pathway in preparation for clinical trials in Birt-Hogg-Dube and sporadic chromophobe RCC. Patients with hereditary leiomyomatosis RCC (HLRCC) are at risk for developing cutaneous and uterine leiomyomas and a very aggressive type of RCC. HLRCC is characterized by germline mutation of the Krebs cycle enzyme, fumarate hydratase (FH). Studies of the tricarboxylic acid cycle and the VHL-HIF pathways have provided the foundation for therapeutic approaches in patients with HLRCC-associated kidney cancer as well as other hereditary and sporadic forms of RCC.

Clinical Efficacy and Toxicity of Anti-EGFR Therapy in Common Cancers

Epidermal growth factor receptor (EGFR) is a cell surface molecule and member of the ErbB family of receptor tyrosine kinases. Its activation leads to proliferation, antiapoptosis, and metastatic spread, making inhibition of this pathway a compelling target. In recent years, an increasing number of clinical trials in the management of solid malignancies have become available indicating the clinical efficacy of anti-EGFR monoclonal antibodies and oral small molecule tyrosine kinase inhibitors (TKIs). This review addresses frequently used EGFR inhibitors, summarizes clinical efficacy data of these new therapeutic agents, and discusses their associated toxicity and management.

Anti-angiogenesis approach to genitourinary cancer treatment

Angiogenesis plays a crucial role in the survival, proliferation, and metastatic potential of several tumors, including genitourinary (GU) cancers. Over the last decade, increasing basic science and clinical research have led to the approval of several angiogenesis inhibitors. GU tumors are unique in its pathogenesis whereby specific pathways, such as involvement of the Von Hippel-Lindau gene in clear cell renal cell cancer and aberrant overexpression of vascular endothelial growth factor in prostatic cancers and transitional cell bladder cancers, allow for potential targeting using angiogenesis inhibitors. This review discusses the biologic pathways as well as the rationale for using angiogenesis inhibitors in renal cell, prostate, and transitional cell bladder cancers. This review also focuses on pivotal trials and emerging data on the use of these inhibitors.

Cardiovascular effects of tyrosine kinase inhibitors used for gastrointestinal stromal tumors

Small-molecule tyrosine kinase inhibitors (TKIs) have revolutionized the targeted treatment of various cancers, including gastrointestinal stromal tumors (GISTs). Recent evidence suggests the possibility of cardiotoxicity secondary to TKI treatment of GISTs. Preclinical studies indicate that imatinib and sunitinib may be directly toxic to cardiac myocytes. Clinically, cardiotoxicity attributable to imatinib seems to be infrequent and manageable, whereas that attributable to sunitinib is more common and more severe. Further prospective studies with objective cardiac monitoring and long-term follow up are needed to define more accurately the incidence, natural history, and risk factors for developing cardiotoxicity associated with TKIs used in the treatment of patients who have GISTs. In this review, the authors discuss what is known regarding the cardiovascular effects of TKIs used in the treatment of GISTs.

Risk of hand-foot skin reaction with the multitargeted kinase inhibitor sunitinib in patients with renal cell and non-renal cell carcinoma: a meta-analysis

Hand-foot skin reaction (HFSR) is an emerging issue in cancer treatment with multitargeted tyrosine kinase inhibitors (TKIs), leading to morbidity, suboptimal dosing, and poor compliance. The overall risk of HFSR is not clear for sunitinib, a TKI effective for metastatic renal cell carcinoma (RCC) and gastrointestinal stromal tumor. We therefore conducted a systematic review and a meta-analysis to determine the risk of developing HFSR with sunitinib. Databases from PubMed and Web of Science for articles from July 1966 until July 2007 and abstracts presented at the American Society of Clinical Oncology conferences were searched to identify relevant studies. Eligible studies were prospective clinical trials that had described events of HFSR for patients who received singleagent sunitinib. Incidence and relative risk (RR) were calculated using a random-effects or fixed-effects model. A total of 5005 patients with RCC and other cancers from 10 clinical trials were included for analysis. Among patients receiving sunitinib, the summary incidences of all-grade and high-grade HFSR were 18.9% (95% CI, 14.1%-24.8%) and 5.5% (95% CI, 3.9%-7.9%), respectively. Interestingly, patients with RCC have significantly decreased risk of HFSR compared with patients with non-RCC malignancy (RR, 0.56; 95% CI, 0.50-0.64; P < .001). In addition, sunitinib was associated with a significantly increased risk of all-grade HFSR (RR, 9.86; 95% CI, 3.1-31.31; P < .001) in comparison with controls. There is a significant risk of developing HFSR in patients with cancer receiving sunitinib. Adequate monitoring and intervention are recommended for reducing the toxicity.

Beyond doublet chemotherapy for advanced non-small-cell lung cancer: combination of targeted agents with first-line chemotherapy

The first-line treatment of advanced non-small-cell lung cancer (NSCLC) has evolved significantly over the past 5 years. As recently as 15 years ago, best supportive care (BSC) was considered an acceptable option for most patients with advanced or metastatic NSCLC, based on the concern that toxic effects of systemic chemotherapy overshadowed any potential benefits. The enhanced efficacy of platinum-based doublet chemotherapeutic regimens led to increases in overall patient survival relative to BSC. However, overall survival (OS) appeared to plateau, even with the introduction and refinement of these regimens. The addition of novel targeted agents targeting growth pathways to platinum-based regimens failed to overcome the 7.8- to 10.5-month survival barrier. After many phase III clinical trials, which involved tyrosine kinase inhibitors, matrix metalloproteinase inhibitors, protein kinase C inhibitors, and retinoids, this survival barrier had yet to be surmounted, although in some cases certain subgroups benefited, suggesting specific molecular correlations. Recently, inhibition of components of the angiogenesis pathway with the addition of bevacizumab to a platinum-based doublet led to statistically significant increases in OS, progression-free survival, and response rate relative to chemotherapy alone. This advance pushed the median survival of selected patients with advanced or metastatic NSCLC who met the eligibility criteria of the trial over the 12-month mark, thus offering patients and clinicians hope for more incremental advances in the future.

Renal cell carcinoma: dynamic contrast-enhanced MR imaging for differentiation of tumor subtypes--correlation with pathologic findings

PURPOSE

To retrospectively evaluate whether the enhancement patterns of pathologically proved clear cell, papillary, and chromophobe renal cell carcinomas (RCCs) measured on clinical dynamic contrast agent-enhanced magnetic resonance (MR) images permit accurate diagnosis of RCC subtype.

MATERIALS AND METHODS

This study was Institutional Review Board approved and HIPAA compliant; informed consent was waived. One hundred twelve patients (76 men, 36 women; age range, 25-88 years; mean age, 58.1 years) underwent MR imaging of 113 renal masses (mean diameter, 5.4 cm) with pathologic diagnoses of clear cell (n = 75), papillary (n = 28), or chromophobe (n = 10) RCC. A 1.5-T clinical MR protocol was used before and after (corticomedullary and nephrographic phases) intravenous administration of contrast agent. Region-of-interest measurements within tumor and uninvolved renal cortex were used to calculate percentage signal intensity change and tumor-to-cortex enhancement index. Subtype groups were compared by using linear mixed-effects models. Receiver operating characteristic (ROC) curve analysis was performed for the comparison of clear cell and papillary RCCs.

RESULTS

On both the corticomedullary and nephrographic phase images, clear cell RCCs showed greater signal intensity change (205.6% and 247.1%, respectively) than did papillary RCCs (32.1% and 96.6%, respectively) (P < .001). Chromophobe RCCs showed intermediate change (109.9% and 192.5%, respectively). The tumor-to-cortex enhancement indexes at corticomedullary and nephrographic phases were largest for clear cell RCCs (1.4 and 1.2, respectively), smallest for papillary RCCs (0.2 and 0.4, respectively), and intermediate for chromophobe RCCs (0.6 and 0.8, respectively). Signal intensity changes on corticomedullary phase images were the most effective parameter for distinguishing clear cell and papillary RCC (area under ROC curve, 0.99); a threshold value of 84% permitted distinction with 93% sensitivity and 96% specificity.

CONCLUSION

Clear cell, papillary, and chromophobe RCCs demonstrate different patterns of enhancement on two-time point clinical dynamic contrast-enhanced MR images, allowing their differentiation with high sensitivity and specificity.

A population pharmacokinetic meta-analysis of sunitinib malate (SU11248) and its primary metabolite (SU12662) in healthy volunteers and oncology patients

PURPOSE

Sunitinib malate is an oral multitargeted tyrosine kinase inhibitor approved for advanced renal cell carcinoma and imatinib-resistant or imatinib-intolerant gastrointestinal stromal tumor. Following administration, sunitinib is metabolized by cytochrome P450 3A4 to an active metabolite (SU12662). The objective of this analysis was to assess sunitinib and SU12662 pharmacokinetics and to identify covariates that might explain variability in exposure following oral administration.

EXPERIMENTAL DESIGN

Data from 590 subjects (73 volunteers and 517 patients) in 14 studies were analyzed. Plasma concentration-time data were analyzed using nonlinear mixed-effects modeling to estimate population pharmacokinetic parameters, as well as relationships between these parameters and gender, race, age, weight, creatinine clearance, Eastern Cooperative Oncology Group score, and tumor type. Simulations were done to determine the predicted effect of these covariates on exposure.

RESULTS

Separate models were developed for sunitinib and SU12662 (each a two-compartment model with first-order absorption and elimination). Sunitinib parameters were estimated as CL/F, 51.8 L/h and Vd/F(central), 2,030 liters. SU12662 parameters were estimated as CL/F, 29.6 L/h and Vd/F(central), 3,080 liters. Tumor type (except acute myeloid leukemia), Asian race, gender, body weight, and elevated Eastern Cooperative Oncology Group score described a portion of the variability in CL/F for sunitinib and metabolite; gender and body weight explained some of the variability in Vd/F(central) for sunitinib and metabolite. Among patients, the predicted changes in sunitinib and metabolite AUC and C(max) as a result of the individual covariates ranged up to 17%.

CONCLUSION

The magnitude of the predicted changes in exposure with the covariates studied minimizes the necessity for dose adjustment in any of these subpopulations.

Renal cell carcinoma

Considerable progress has been made in the treatment of patients with renal cell carcinoma, with innovative surgical and systemic strategies revolutionising the management of this disease. In localised disease, partial nephrectomy for small tumours and radical nephrectomy for large tumours continue to be the gold-standard treatments, with emphasis on approaches that have reduced invasiveness and preserve renal function. Additionally, cytoreductive nephrectomy is often indicated before the start of systemic treatment in patients with metastatic disease as part of integrated management strategy. The effectiveness of immunotherapy, although previously widely used for treatment of metastatic renal cell carcinoma, is still controversial, and is mainly reserved for patients with good prognostic factors. Development of treatments that have specific targets in relevant biological pathways has been the main advance in treatment. Targeted drugs, including inhibitors of the vascular endothelial growth factor and mammalian target of rapamycin pathways, have shown robust effectiveness and offer new therapeutic options for the patients with metastatic disease.

In vitro to in vivo concordance of a high throughput assay of bone marrow toxicity across a diverse set of drug candidates

The development of predictive toxicology assays is necessary to optimize the drug candidate selection process. The colony forming assay (CFA) is used routinely to assess bone marrow toxicity and represents a viable tool for the discovery toxicologist, but the assay is not widely accepted as a standard screening tool due to technical challenges. A higher throughput and standardized version of the assay recently was developed such that the proliferative capacity of a cell lineage is measured indirectly via ATP levels, replacing the cumbersome identification and enumeration of specific colonies. In this study, a high-throughput assay of bone marrow toxicity prediction using the granulocyte, erythrocyte, monocyte, and macrophage (GEMM) progenitor cell lineage was evaluated using a training set of 56 structurally diverse compounds with known in vivo bone marrow effects. In general, compounds identified as toxic in vivo had lower IC(50) values, whereas those identified as non-toxic had higher IC(50) values. Concordance (i.e., predictive accuracy) to in vivo bone marrow toxicity results was 82% when an in vitro toxicity threshold of 20 microM was used. Additional experiments in other hematopoietic lineages were conducted to determine if predictivity of several false positive and negative compounds in the GEMM lineage could be improved; however an increase in sensitivity or specificity was not observed. The high-throughput GEMM assay has good concordance to in vivo bone marrow toxicity results and, with the high-throughput and standardized format, can be incorporated readily into the pharmaceutical toxicological screening paradigm, aiding in the early identification of compounds that eventually may fail due to bone marrow toxicity.

The novel role of tyrosine kinase inhibitor in the reversal of immune suppression and modulation of tumor microenvironment for immune-based cancer therapies

In tumor-bearing hosts, myeloid-derived suppressor cells (MDSC) and T regulatory cells (Treg) play important roles in immune suppression, the reversal of which is vitally important for the success of immune therapy. We have shown that ckit ligand is required for MDSC accumulation and Treg development. We hypothesized that sunitinib malate, a receptor tyrosine kinase inhibitor, could reverse MDSC-mediated immune suppression and modulate the tumor microenvironment, thereby improving the efficacy of immune-based therapies. Treatment with sunitinib decreased the number of MDSC and Treg in advanced tumor-bearing animals. Furthermore, it not only reduced the suppressive function of MDSCs but also prevented tumor-specific T-cell anergy and Treg development. Interestingly, sunitinib treatment resulted in reduced expression of interleukin (IL)-10, transforming growth factor-beta, and Foxp3 but enhanced expression of Th1 cytokine IFN-gamma and increased CTL responses in isolated tumor-infiltrating leukocytes. A significantly higher percentage and infiltration of CD8 and CD4 cells was detected in tumors of sunitinib-treated mice when compared with control-treated mice. More importantly, the expression of negative costimulatory molecules CTLA4 and PD-1 in both CD4 and CD8 T cells, and PDL-1 expression on MDSC and plasmacytoid dendritic cells, was also significantly decreased by sunitinib treatment. Finally, sunitinib in combination with our immune therapy protocol (IL-12 and 4-1BB activation) significantly improves the long-term survival rate of large tumor-bearing mice. These data suggest that sunitinib can be used to reverse immune suppression and as a potentially useful adjunct for enhancing the efficacy of immune-based cancer therapy for advanced malignancies.

Sunitinib mediates reversal of myeloid-derived suppressor cell accumulation in renal cell carcinoma patients

PURPOSE

Immune dysfunction reported in renal cell carcinoma (RCC) patients may contribute to tumor progression. Myeloid-derived suppressor cells (MDSC) represent one mechanism by which tumors induce T-cell suppression. Several factors pivotal to the accumulation of MDSC are targeted by the tyrosine kinase inhibitor, sunitinib. The effect of sunitinib on MDSC-mediated immunosuppression in RCC patients has been investigated.

EXPERIMENTAL DESIGN

Patient peripheral blood levels of MDSC and regulatory T-cell (Treg) and T-cell production of IFN-gamma were evaluated before and after sunitinib treatment. Correlations between MDSC and Treg normalization as well as T-cell production of IFN-gamma were examined. The in vitro effect of sunitinib on patient MDSC was evaluated.

RESULTS

Metastatic RCC patients had elevated levels of CD33(+)HLA-DR(-) and CD15(+)CD14(-) MDSC, and these were partially overlapping populations. Treatment with sunitinib resulted in significant reduction in MDSC measured by several criteria. Sunitinib-mediated reduction in MDSC was correlated with reversal of type 1 T-cell suppression, an effect that could be reproduced by the depletion of MDSC in vitro. MDSC reduction in response to sunitinib correlated with a reversal of CD3(+)CD4(+)CD25(hi)Foxp3(+) Treg cell elevation. No correlation existed between a change in tumor burden and a change in MDSC, Treg, or T-cell production of IFN-gamma. In vitro addition of sunitinib reduced MDSC viability and suppressive effect when used at >/=1.0 microg/mL. Sunitinib did not induce MDSC maturation in vitro.

CONCLUSIONS

Sunitinib-based therapy has the potential to modulate antitumor immunity by reversing MDSC-mediated tumor-induced immunosuppression.

Hypercoagulability as a prognostic factor for survival in patients with metastatic renal cell carcinoma

Background

In experimental systems, interference with coagulation can affect tumor biology. We suggested that abnormal coagulation could be a negative predictor for response to immunotherapy and survival among patients with metastatic renal cell carcinoma (MRCC).

Methods

To address this issue, retrospective analysis of 289 previously untreated MRCC patients entering on institutional review board-approved clinical trials was conducted between 2003 and 2006. In addition, two groups of MRCC patients with (n = 28) or without (n = 28) hypercoagulability were compared in a case-control study. Baseline and treatment characteristics were well balanced.

Results

Hypercoagulability was present at treatment start in 40% of patients. Median baseline fibrinogen was 6.2 mg/dl. Serious disorders were found in 68% of patients. Abnormal coagulation was strongly associated with a number of metastatic sites (2 and more metastatic sites vs. 0–1 (P = .001). Patients with high extent of hypercoagulability had significantly higher number of metastatic sites (P = .02). On univariate analysis, patients with hypercoagulability had significantly shorter overall survival than patients with normal coagulation; median survivals of 8.9 and 16.3, respectively (P = .001).

Short survival and low response rate also were significantly associated with hypercoagulability in a case-control study. Median survival was 8.2 months and 14.6 months, respectively (P = .0011). Disease control rate (overall response + stable disease) was significantly higher in patients with normal coagulation: 71.4 versus 42.9% (P = .003).

Conclusion

Hypercoagulability disorders were found to be prognostic factor for response rate to systemic therapy and survival in patients with MRCC.

Rapid improvement in pain and functional level in a patient with metastatic renal cell carcinoma: a case report and review of the literature

Renal cell carcinoma (RCC) represents approximately 3% of all adult cancers and is more common in males. Systemic treatment for RCC has improved following the introduction of sunitinib. Bone metastases are present in up to 50% of RCC patients. We report a case of rapid improvement in metastatic bone lesions, recorded by nuclear bone scan, in a male patient receiving localized palliative radiotherapy in addition to systemic sunitinib and zoledronic acid. Concurrently, quality of life and performance status improved dramatically. Although we are unsure of the exact mechanism for such rapid improvement in metastatic bone lesions, the swiftness this improvement deserves reporting.

Molecular Pathology of the Genitourinary Tract: Molecular Pathology of Kidney and Testes

With the advent of newer molecular technologies, our knowledge of cellular mechanisms with tumors of the kidney and testis has grown exponentially. Molecular technologies have led to better understanding of interplay between the von Hippel-Lindau gene and angiogenic cytokines in renal cancer and isochromosome 12p in testicular neoplasms. The result has been development of antiangiogenic-targeted therapy within recent years that has become the mainstay treatment for metastatic renal cell cancer. In the near future, classification and diagnosis of renal and testicular tumors through morphologic analysis will be supplemented by molecular information correlating to prognosis and targeted therapy. This article outlines tumor molecular pathology of the kidney and testis encompassing current genomic, epigenomic, and proteonomic findings.

The clinical implications of the genetics of renal cell carcinoma

Over the last several decades, the advances in molecular genetics have elucidated kidney cancer gene pathways. Kidney cancer is a heterogeneous disorder. Each specific type of kidney cancer has its own histologic features, gene, and clinical course. Insight into the genetic basis of kidney cancer has been learned largely from the study of the familial or hereditary forms of kidney cancer. Extirpative surgery is currently the treatment of choice for kidney cancer that is confined to the kidney. Treatment for advanced or metastatic kidney cancer is a formidable challenge with the traditional therapies currently available. However, investigation of the Mendelian single-gene syndromes, like von Hippel Lindau (VHL: VHL gene), hereditary papillary renal carcinoma (HPRC: c-Met gene), Birt-Hogg-Dubé (BHD: BHD gene), and hereditary leiomyomatosis renal cell cancer (HLRCC: fumarate hydratase gene) provides an opportunity to develop pathway specific therapies. Advances in molecular therapeutics offer novel treatment options for patients with advanced disease.

Management of side effects associated with sunitinib therapy for patients with renal cell carcinoma

Advances in the understanding of the biology of renal cell carcinoma have led to recent approval of several new agents including drugs that target vascular endothelial growth factor. Sunitinib is an oral tyrosine kinase inhibitor which interferes with multiple intracellular tumorogenic pathways, and has demonstrated impressive antitumor activity in phase II and subsequently improvement in progression free survival in phase III renal cancer trials. We review the unique side effects of sunitinib therapy with emphasis on establishing effective patient education for anticipation and early management of therapy-related side effects.

Sensitization of ABCG2-overexpressing cells to conventional chemotherapeutic agent by sunitinib was associated with inhibiting the function of ABCG2

Sunitinib is an ATP-competitive multi-targeted tyrosine kinase inhibitor. In this study, we evaluated the possible interaction of sunitinib with P-glycoprotein (P-gp, ABCB1), multidrug resistance protein 1 (MRP1, ABCC1), breast cancer resistance protein (BCRP, ABCG2) and lung-resistance protein (LRP) in vitro. Our results showed that sunitinib completely reverse drug resistance mediated by ABCG2 at a non-toxic concentration of 2.5muM and has no significant reversal effect on ABCB1-, ABCC1- and LRP-mediated drug resistance, although a small synergetic effect was observed in combining sunitinib and conventional chemotherapeutic agents in ABCB1 overexpressing MCF-7/adr and parental sensitive MCF-7 cells, ABCC1 overexpressing C-A120 and parental sensitive KB-3-1 cells. Sunitinib significantly increased intracellular accumulation of rhodamine 123 and doxorubicin and remarkably inhibited the efflux of rhodamine 123 and methotrexate by ABCG2 in ABCG2-overexpressing cells, and also profoundly inhibited the transport of [(3)H]-methotrexate by ABCG2. However, sunitinib did not affect the expression of ABCG2 at mRNA or protein levels. In addition, sunitinib did not block the phosphorylation of Akt and Erk1/2 in ABCG2-overexpressing or parental sensitive cells. Overall, we conclude that sunitinib reverses ABCG2-mediated MDR through inhibiting the drug efflux function of ABCG2. These findings may be useful for cancer combinational therapy with sunitinib in the clinic.

Phase I trial of bevacizumab plus escalated doses of sunitinib in patients with metastatic renal cell carcinoma

PURPOSE

Both bevacizumab and sunitinib target the vascular endothelial growth factor pathway and demonstrate activity against advanced renal cell carcinoma (RCC). In this phase I study, the maximum-tolerated dose (MTD) and safety of sunitinib in combination with bevacizumab were examined in patients with advanced RCC.

PATIENTS AND METHODS

Three cohorts of three to six patients were treated with escalated doses of daily oral sunitinib (ie, 25 mg, 37.5 mg, 50 mg) for 4 weeks followed by a 2-week break and with fixed doses of bevacizumab (10 mg/kg) intravenously once every 2 weeks. Dose-limiting toxicities (DLTs) were assessed during the first cycle to determine the MTD, and an expanded cohort was treated to obtain additional safety information.

RESULTS

Of 26 study participants, 25 received treatment at one of three dose levels. Grade 4 hemorrhage, identified as a DLT, occurred in one patient in each of cohorts 2 and 3. The MTD was determined to be sunitinib 50 mg/bevacizumab 10 mg/kg, but chronic therapy at this dose level frequently resulted in grades 3 to 4 hypertension and hematologic and vascular toxicities. Overall, 48% of patients discontinued treatment because of adverse events. One complete and 12 partial responses were observed, which provided an objective response rate of 52%.

CONCLUSION

In this phase I trial of patients with metastatic RCC, the combination of sunitinib and bevacizumab caused a high degree of hypertension and vascular and hematologic toxicities at the highest dose level. We do not plan to pursue additional study of this regimen at these doses in patients with RCC.

A report of succinate dehydrogenase B deficiency associated with metastatic papillary renal cell carcinoma: successful treatment with the multi-targeted tyrosine kinase inhibitor sunitinib

We report a patient who initially presented with an abdominal paraganglioma and subsequently metastatic papillary cell renal cancer. Genetic analysis revealed a 141 G>A (exon 2) Trp47X mutation within the succinate dehydrogenase B gene. Treatment with the novel multi-targeted tyrosine kinase inhibitor sunitinib resulted in a sustained partial response and reduced the level of the angiogenic marker PIGF.

TRIAL REGISTRATION NUMBER

a6181037.