Sunitinib in patients with metastatic renal cell carcinoma

Renal cell carcinoma

PURPOSE OF REVIEW

This review highlights recent contributions to the biology and treatment of renal cell carcinoma, the expanded use of antiangiogenic agents as well as interest in other inhibitory drug mechanisms. In addition, recent findings are reported on biomarkers which are undergoing investigation as correlative prognostic indicators of either survival or response to treatment.

RECENT FINDINGS

Advances in our understanding of the molecular biology underpinning renal cell carcinoma and the introduction of new targeted therapeutics with benefit in the metastatic setting have had a major impact on the treatment of this disease.

SUMMARY

The management of metastatic renal cell carcinoma has undergone a dramatic evolution in the past year, marked by the approval of two drugs by the US Food and Drug Administration. These drugs have demonstrated improved progression-free survival as well as potentially improved overall survival for patients with metastatic disease. These groundbreaking treatment strategies have fueled a surge in translational studies expanding our knowledge of the molecular biology of renal cell carcinoma.

Vascular endothelial growth factor-targeted therapy in renal cell carcinoma: current status and future directions

Renal cell carcinoma is a highly vascular tumor associated with expression of vascular endothelial growth factor (VEGF). Recently, VEGF-targeted therapies have been identified as a promising therapeutic approach. Three agents targeting the VEGF pathway have shown clinical activity as monotherapy in metastatic renal cell carcinoma: the anti-VEGF monoclonal antibody, bevacizumab, and small-molecule VEGF receptor tyrosine kinase inhibitors, sorafenib and sunitinib. This article explores these agents in terms of their mechanisms of action, clinical efficacy, and toxicity profiles. This article also reviews future development strategies, including combination regimens and drug sequencing, trial design considerations, and patient selection opportunities.

The evolving role of surgery for advanced renal cell carcinoma in the era of molecular targeted therapy

PURPOSE

Thoughtful integration of surgical and medical approaches to metastatic renal cell carcinoma is paramount for maximizing disease control. Accomplishing this in the current era of targeted molecular therapies presents unique challenges and opportunities.

MATERIALS AND METHODS

A systematic review of the MEDLINE and PubMed databases, and relevant urological and oncological journals was performed pertaining to cytoreductive nephrectomy, metastasectomy, targeted molecular therapies for renal cell carcinoma, and neoadjuvant and adjuvant approaches to the management of advanced renal cell carcinoma.

RESULTS

Cytoreductive nephrectomy provides an overall survival advantage in select patients with metastatic renal cell carcinoma who receive subsequent interferon-alpha. However, cytokine therapies are now being supplanted by targeted molecular approaches that block the effects of vascular endothelial growth factor and other molecular events. Although cytoreductive nephrectomy remains a standard of care, limited insight into the biological effects of nephrectomy on mechanisms such as immunoregulation and angiogenesis precludes definitive statements about how to integrate surgery and targeted agents. Ongoing investigation involving basic science and translational research is required to optimize the integration of these approaches. Adjuvant and neoadjuvant vascular endothelial growth factor targeted approaches to renal cell carcinoma are now also being explored and the unique side effects of these agents, including potential effects on wound healing and vascular integrity, require careful consideration.

CONCLUSIONS

Integrated approaches involving surgery and vascular endothelial growth factor targeted therapies hold much promise for the management of advanced renal cell carcinoma. Prospective clinical testing with vigilant attention to the risk-benefit ratio and thoughtful evaluation of biological correlates are required to optimize these approaches.

Targeting the PI3K-Akt pathway in kidney cancer

Kidney cancer, or renal cell carcinoma, is a relatively rare malignancy but is metastatic at diagnosis in a third of patients; metastatic disease has a dismal prognosis. Conventional chemotherapy has been woefully inadequate, thus novel targets for 'designer' therapies are being actively evaluated. The PI3K-Akt signaling cascade, owing to its dual role in both survival and mitogenic signaling, is in theory an ideal therapeutic target for this disease, but may also represent its fatal flaw. Thus, largely due to toxicity issues, no PI3K or Akt inhibitors are currently ready for clinical application. In this review, we discuss PI3K-Akt inhibitors as well as inhibitors of pathways and targets both immediately up- and downstream of this cascade, many of which show promise in the clinic.

Prognostic relevance of the mTOR pathway in renal cell carcinoma: implications for molecular patient selection for targeted therapy

BACKGROUND

The mammalian target of rapamycin (mTOR) pathway is up-regulated in many human cancers, and agents targeting the mTOR pathway are in various stages of clinical development. The goal of the study was to evaluate the potential and limitations of targeting the mTOR pathway in renal cell carcinoma (RCC).

METHODS

Immunohistochemical analysis using antibodies against pAkt, PTEN, p27, and pS6 was performed on a tissue microarray constructed from paraffin-embedded specimens from 375 patients treated by nephrectomy for RCC. The expression was associated with pathological parameters and survival.

RESULTS

The mTOR pathway was more significantly altered in clear-cell RCC, high-grade tumors, and tumors with poor prognostic features. PS6 and PTEN showed the strongest associations with pathological parameters. Survival tree analysis regarding expression of cytoplasmic pAkt, nuclear pAkt, PTEN, cytoplasmic p27, and pS6 identified staining percentages of 40%, 10%, 75%, 7%, and 70%, respectively, as ideal cutoff values for stratification, with corresponding P-values of .03, .001, .02, .005, and <.0001, respectively. Interestingly, high nuclear pAkt expression was associated with a favorable prognosis, whereas high cytoplasmic pAkt expression was associated with a poor prognosis. In multivariate Cox regression analysis, ECOG PS, T classification, N classification, M classification, cytoplasmic Akt, nuclear pAkt, PTEN, and pS6 were independent prognostic factors of DSS.

CONCLUSIONS

Components of the mTOR pathway are significantly associated with pathological features and survival. Not all RCC tumor types seem to be equally amenable to mTOR targeted therapy. PTEN, pAkt, p27, and pS6 may serve as surrogate parameters for patient selection and predicting prognosis. Patients with a highly activated mTOR pathway should benefit most from this therapy. External validation of our results is recommended.

Circulating protein biomarkers of pharmacodynamic activity of sunitinib in patients with metastatic renal cell carcinoma: modulation of VEGF and VEGF-related proteins

BACKGROUND

Sunitinib malate (SUTENT) is an oral, multitargeted tyrosine kinase inhibitor, approved multinationally for the treatment of advanced RCC and of imatinib-resistant or - intolerant GIST. The purpose of this study was to explore potential biomarkers of sunitinib pharmacological activity via serial assessment of plasma levels of four soluble proteins from patients in a phase II study of advanced RCC: VEGF, soluble VEGFR-2 (sVEGFR-2), placenta growth factor (PlGF), and a novel soluble variant of VEGFR-3 (sVEGFR-3).

METHODS

Sunitinib was administered at 50 mg/day on a 4/2 schedule (4 weeks on treatment, 2 weeks off treatment) to 63 patients with metastatic RCC after failure of first-line cytokine therapy. Predose plasma samples were collected on days 1 and 28 of each cycle and analyzed via ELISA.

RESULTS

At the end of cycle 1, VEGF and PlGF levels increased >3-fold (relative to baseline) in 24/54 (44%) and 22/55 (40%) cases, respectively (P < 0.001). sVEGFR-2 levels decreased >or= 30% in 50/55 (91%) cases and >or= 20% in all cases (P < 0.001) during cycle 1, while sVEGFR-3 levels were decreased >or= 30% in 48 of 55 cases (87%), and >or= 20% in all but 2 cases. These levels tended to return to near-baseline after 2 weeks off treatment, indicating that these effects were dependent on drug exposure. Overall, significantly larger changes in VEGF, sVEGFR-2, and sVEGFR-3 levels were observed in patients exhibiting objective tumor response compared with those exhibiting stable disease or disease progression (P < 0.05 for each analyte; analysis not done for PlGF).

CONCLUSION

Sunitinib treatment in advanced RCC patients leads to modulation of plasma levels of circulating proteins involved in VEGF signaling, including soluble forms of two VEGF receptors. This panel of proteins may be of value as biomarkers of the pharmacological and clinical activity of sunitinib in RCC, and of angiogenic processes in cancer and other diseases.

Consolidative Renal Cell Carcinoma Metastatectomy for Partial Response After Multitargeted Tyrosine Kinase Inhibitor Therapy

The advent of molecularly targeted agents is rapidly changing the management of metastatic renal cell carcinoma. A case in which surgical metastatectomy was used in the setting of dramatic but incomplete disease response to sunitinib is presented. Some of the issues complicating operative intervention in the setting of multitargeted tyrosine kinase inhibitors are discussed.

A Belgian registry of interleukin-2 administration for treatment of metastatic renal cell cancer and confrontation with literature data

In an effort to map the use of interleukin-2 (IL-2) treatment in patients with clear cell renal cell cancer (RCC) in Belgian hospitals, 44 cases were registered from 9 hospitals between February 2003 and June 2006. It was demonstrated that the majority of these patients were treated with subcutaneous (SC) IL-2. Other methods such as the inhalation of the drug in case of intrathoracic disease or high dose intravenous (IV) administration were much less frequent (3 and 0 cases in this registry, respectively). The results of antitumour activity (around 16% partial response-absence of complete responses) and toxicity of this drug correlate with observations from the literature with the SC administration. In view of the poor results and tolerance with the currently used cytokines (IL-2 or interferon-alfa), much hope is directed towards the development of the novel targeted drugs like sunitinib or sorafenib used alone or in combination with cytokines in this disease.

Molecular insight in cancer treatment and prevention

This article explores the impact of new insights in the biology of cancer on the treatment and the prevention of this disease. There are two types of targeted cancer treatment, afforded by the molecular profile of cancer. One concerns the use of agents targeted on a specific component of the cancer cells (e.g., CD20 in lymphoma) or on a specific survival function of the cancer cell (growth-factor-receptor interaction; transduction cascade). The other concerns the recognition of tumors that are more or less likely to benefit from cytotoxic chemotherapy according to their genomic or proteomic profile. Cancer prevention may benefit from new molecular insight in cancer biology as these processes allow early diagnosis of cancer, identification of patients at risk for cancer, and may provide intermediate markers for chemoprevention studies.

Recent advances in the therapy of renal cancer

Metastatic clear cell renal cell cancer has traditionally been treated with cytokines (interferon or interleukin-2). Improved understanding of biology has engendered novel targeted therapeutic agents that have radically altered the outlook. Vascular endothelial growth factor, the related receptor and the mTOR signal transduction pathway have particularly been exploited. Sunitinib malate, sorafenib and temsirolimus have improved clinical outcomes compared with interferon in randomized trials. Other multitargeted tyrosine kinase inhibitors (lapatinib, axatinib and pazopanib) and antiangiogenic agents (bevacizumab and lenalidomide) have also demonstrated activity in early studies. Combinations of these agents are being evaluated. The future of the therapy of renal cancer appears promising owing to the efficacy of these novel agents. Clinical trials designed to further assess these and other agents need to be vigorously supported.

Design of clinical trials of radiation combined with antiangiogenic therapy

Clinical trials showing longer survival when chemotherapy is combined with antiangiogenic agents (AAs) have led to growing interest in designing combined modality protocols that exploit abnormalities in tumor vasculature. Approved agents include bevacizumab, a recombinant monoclonal antibody that binds to vascular endothelial growth factor, and two small molecule multitargeted tyrosine kinase inhibitors of angiogenesis (SU11248 and BAY-43-9006) that have been approved for therapy of renal cancer. Targeting tumor vasculature has a strong biological rationale in radiation therapy, and preclinical studies consistently show an increase in radiosensitization with combined treatment. Preclinical studies indicate that excessive damage to tumor vasculature can result in radioresistance in some situations, and early clinical data suggest that treatment sequencing may be important when combining AAs with radiation. Radiation itself appears to antagonize any hypoxia that can be induced by long-term administration of AAs. The optimal biological doses of AAs with radiotherapy are unknown, and surrogate markers of efficacy remain to be validated. Early clinical trials should therefore include studies designed to identify mechanisms of interaction and increases in tumor hypoxia. This review highlights preclinical and early clinical data that are relevant for clinical trial design. Optimal radiation planning and delivery is required to minimize the volume of irradiated normal organs and to establish safe dose-volume parameters for phase II-III clinical trials.

Mechanisms of adverse effects of anti-VEGF therapy for cancer

Advances in understanding the role of vascular endothelial growth factor (VEGF) in normal physiology are giving insight into the basis of adverse effects attributed to the use of VEGF inhibitors in clinical oncology. These effects are typically downstream consequences of suppression of cellular signalling pathways important in the regulation and maintenance of the microvasculature. Downregulation of these pathways in normal organs can lead to vascular disturbances and even regression of blood vessels, which could be intensified by concurrent pathological conditions. These changes are generally manageable and pose less risk than the tumours being treated, but they highlight the properties shared by tumour vessels and the vasculature of normal organs.

Sunitinib: a novel tyrosine kinase inhibitor. A brief review of its therapeutic potential in the treatment of renal carcinoma and gastrointestinal stromal tumors (GIST)

Sunitinib malate is a novel oral multitargeted tyrosine kinase inhibitor with antitumor and antiangiogenic activities. Sunitinib was recently approved in first-line treatment for patients with advanced renal cell carcinoma (RCC) and for the treatment of patients with gastrointestinal stromal tumors (GIST) after disease progression or intolerance to imatinib mesylate therapy. We report the very interesting results of the phase II trials after cytokin failure and of the randomized recent trial of sunitinib versus cytokin-based therapy in first-line treatment for patients with metastatic RCC, as well as the promising results of the recent trials on patients with GIST after disease progression or intolerance to imatinib mesylate therapy. Oral sunitinib demonstrates a high level of efficacy with acceptable tolerability with the 50 mg daily for 4 weeks followed by 2 weeks off schedule; a continuous schedule could be of interest. Hypertension and asthenia are the most common side effects with sunitinib. Regardless of these encouraging results, studies investigating sunitinib in first-line treatment (for patients with GIST), adjuvant and neoadjuvant settings are awaited, as well as trials using sunitinb in combination with chemotherapy or other targeted therapies. Clinical trials investigating sunitinib in other tumor types are ongoing.

Possible molecular mechanisms involved in the toxicity of angiogenesis inhibition

Contrary to initial expectations, angiogenesis inhibitors can cause toxicities in patients with cancer. The toxicity profiles of these inhibitors reflect the disturbance of growth factor signalling pathways that are important for maintaining homeostasis. Experiences with angiogenesis inhibitors in clinical trials indicate that short-term toxicities are mostly manageable. However, these agents will also be given in prolonged treatment strategies, so we need to anticipate possible long-term toxicities. In addition, understanding the molecular mechanisms involved in the toxicity of angiogenesis inhibition should allow more specific and more potent inhibitors to be developed.

A Review on Follow-Up Strategies for Renal Cell Carcinoma after Nephrectomy

OBJECTIVES

To provide a comprehensive review of the evidence supporting the necessity for follow-up after nephrectomy for renal cell carcinoma.

METHODS

We searched the Medline, MeSH, EMBASE, and Cochrane databases using the terms "renal cell cancer," "kidney neoplasm," "follow-up," "surveillance," "prognosis," and "staging" to look for human/English language/Randomized Controlled Trials/Clinical trials/Review articles/Meta-analysis/Practiced Guidelines, and Editorials.

RESULTS

No consensus currently exists on surveillance guidelines after radical or partial nephrectomy for renal cell carcinoma. The rationale for follow-up strategies is to detect local recurrence or metastatic disease and to allow appropriate treatment. Most of the surveillance protocols recommend various follow-up strategies for all tumour stages. The emphasis on follow-up should be during the first 3-5 yr after nephrectomy. There is no consensus about which investigations should be performed and at what intervals. Most surgeons rely on symptom enquiry, physical examination, chest x-ray, and computed tomography scanning. A protocol based on the stage of the initial tumour is adapted by the majority of the investigators. Patients should be followed similarly after radical or partial nephrectomy on the basis of stage-oriented protocols. The combination of various prognostic factors requires further validation over stage-based protocols. There is a paucity of guidelines in the literature regarding follow-up for patients with hereditary forms of renal cell carcinoma.

CONCLUSIONS

Current guidelines for follow-up are based on observational and case studies. While this fact precludes a high level of evidence-based guidelines, we have to conclude that this is the best available evidence to date.

Sunitinib: bridging present and future cancer treatment

Tyrosine kinase receptors (RTKs) are a heterogeneous group of transmembrane proteins involved in signal transduction. These receptors are expressed in many different cells and regulate cellular growth, differentiation and angiogenesis. Overexpression and/or the structural alteration of different RTKs classes are generally associated to cancer and, when RTKs-mediated signal transduction pathways are abnormally activated, generate cancer growth, angiogenesis and metastatization. Therapeutic intervention targeting RTKs concerns antagonist drugs as little molecules or monoclonal antibodies. Sunitinib malate is a little molecule able to block intracellular tyrosine kinase domain of RTKs, which has both direct anticancer and antiangiogenetic activity. Sunitinib targets selectively vascular endothelial growth factor, KIT, Flt3 and platelet-derived growth factor receptors and the receptor encoded by the ret proto-oncogene. This drug is used in the treatment of gastrointestinal stromal cancer (GIST) resistant to imatinib and metastatic renal cell carcinoma (RCC). In this review, we report preclinical data of sunitinib, even about synergism with chemotherapy and radiotherapy, data relative to phase III trials of sunitinib in the treatment of GIST and RCC, and we try to plan what will be future applications of sunitinib in different types of cancer, even in association to chemotherapy, radiotherapy and monoclonal antibodies.

Recent developments in renal cell cancer immunotherapy

Various immunotherapeutic approaches for the treatment of renal cell carcinoma (RCC) have been developed for > 90 years. Existing immunotherapeutic strategies against RCC include: systemic administration of cytokines; therapeutic vaccines based on tumor cells or dendritic cells; monoclonal antibodies; and adoptive immunotherapy (T cell transfer or allogeneic hematopoietic cell transplantation). However, the overall efficacy of immunotherapy for advanced RCC remains moderate. With the advent of molecularly targeted biological therapies that turned out to be significantly effective in the treatment of metastatic RCC, to many oncologists immunotherapy may seem to be moving into the periphery of RCC treatment strategies. However, for the last 2 years there has been significant progress made in immunotherapeutic approaches for the treatment of RCC. Immunotherapy still remains the only systemic therapeutic strategy that is believed to potentially cure RCC patients. The development of active and passive specific immunotherapeutic approaches, along with the possibility to 'switch off' particular immunosuppressive mechanisms (e.g., elimination of regulatory T cells, blockage of cytotoxic T lymphocyte antigen-4 signaling), have paved the way for future trials of new immunotherapies of RCC. However, the new studies will have to enroll optimally selected patients (nephrectomized, with non-massive metastases and good performance status) and will use tumor response criteria that are specifically optimized for clinical trials of immunotherapy.

A phase I and pharmacokinetic study of sunitinib administered daily for 2 weeks, followed by a 1-week off period

PURPOSE

Sunitinib, an oral multitargeted tyrosine kinase inhibitor that inhibits VEGFR, PDGFR, FLT3, KIT, and RET, is currently approved for the treatment of imatinib-refractory GIST and advanced renal cell carcinoma at a dose of 50 mg daily for 4 weeks followed by a 2-week off period (4/2 schedule). This trial was performed to investigate the safety, tolerability, and pharmacokinetics of sunitinib 50 mg daily for 2 weeks followed by a 1-week off period (2/1 schedule).

EXPERIMENTAL DESIGN

Twelve patients with advanced refractory malignancies were treated with sunitinib on the 2/1 schedule. Intensive safety monitoring included serial measurements of left ventricular ejection fraction (LVEF). Extensive pharmacokinetic sampling was performed on days 1 and 14 of course 1, and on day 14 of courses 2 and 3 to evaluate sunitinib and the SU12662 metabolite.

RESULTS

Twelve patients received a total of 50 courses with an average (+/-SD) off-drug period of 11.5 +/- 5.7 days. Two patients experienced DLT: one patient had asymptomatic grade 4 elevations in lipase and amylase, and another patient had an asymptomatic grade 2 decline in LVEF in course 1. In total, five patients demonstrated asymptomatic grade 2 declines in LVEF. Other principal effects were similar to previous experience with sunitinib, including fatigue, myelosuppression, skin discoloration, and gastrointestinal effects. Pharmacokinetic studies revealed no significant accumulation of sunitinib or SU12662. One patient with papillary thyroid cancer developed a partial response, and was on study for 16 courses, followed by an additional 18 courses on a continuation protocol.

CONCLUSIONS

The 2/1 schedule of sunitinib 50 mg was tolerable, and no significant drug accumulation was demonstrated. The safety profile on this schedule was consistent with the safety profile of sunitinib when administered on a 4-week on, 2-week off schedule.

Vascular endothelial growth factor gene polymorphisms are associated with prognosis in ovarian cancer

PURPOSE

Vascular endothelial growth factor (VEGF), an important regulator of angiogenesis and vascular permeability, is involved in various steps of ovarian carcinogenesis. Gene polymorphisms within the gene encoding VEGF were shown to be independently associated with an adverse outcome in various malignancies. No data are available for ovarian cancer.

EXPERIMENTAL DESIGN

In the present multicenter study, we examined three common polymorphisms within the VEGF gene (-634G/C, -1154G/A, and -2578C/A) known to be associated with an increased VEGF production in 563 Caucasian patients with ovarian cancer from Austria and Germany using pyrosequencing. Results were correlated with clinical data.

RESULTS

The three investigated polymorphisms did not correlate with any of the investigated clinicopathologic variables. In univariate and multivariate models, no significant correlations between any polymorphism and patients' overall survival were ascertained. Simultaneous carriage of the three homozygous genotypes (i.e., VEGF -634C/C, VEGF -1154G/G, VEGF -2578C/C) known to be associated with increased VEGF expression in an individual patient, however, was independently associated with a shortened overall survival (hazard ratio, 2.1; 95% confidence interval, 1.1-3.9; P=0.02).

CONCLUSIONS

We present the first data on VEGF gene polymorphisms in ovarian cancer. Simultaneous carriage of the three investigated homozygous genotypes was shown to be an independent adverse prognosticator of overall survival.

Immuntherapie des metastasierten Nierenzellkarzinoms mit Interleukin-2, Interferon-α2a und Erythropoetin-β

BACKGROUND

The combination of interferon-alpha2a (IFN-alpha2a) and interleukin-2 (IL-2) induces objective responses in patients with metastatic renal cell carcinoma (MRCC). Anaemia is associated with poor cancer control and reduced quality of life. The aim of the study was to investigate response rate and quality of life in patients with MRCC receiving the combination of Erythropoetin, IFN-alpha2a and IL-2.

MATERIAL AND METHOD

Patients with MRCC received epoetin beta (150 IU/kg and haemoglobin <130 g/l or 75 IU/kg and haemoglobin >or=130 g/l) three times weekly, from 14 days before and continuing throughout immunotherapy. In weeks 3-6 the patients received IFN-alpha2a 6 x 10(6) IU/m2 and IL-2 4.5 x 10(6) IU/m2 three times weekly on days 1, 3 and 5. The treatment was repeated two times and in the case of success a third cycle was added. The quality of life was assessed with the FACT questionnaire for fatigue, before, during and after therapy.

RESULTS

A total of 21 patients were treated, 19 of whom could be evaluated concerning response, toxicity and quality of life. We observed 1 complete remission, 2 partial remissions, 5 cases of stable disease and 11 with progressive disease. The overall response rate was 16%. Toxicity was mild to moderate; there were no WHO grade III or IV toxicity. The quality of life increased in ten patients, nine of whom exhibited an increase in their haemoglobin during therapy. Five of the nine patients with decreased quality of life also experienced a decrease in their haemoglobin. The correlation of increased haemoglobin and quality of life was significant (p<0.05).

CONCLUSION

The combination of IFN-alpha2a, IL-2 and epoetin beta resulted in objective remissions with mild to moderate toxicity. The quality of life correlates significantly with increasing haemoglobin.

Wirksamkeit von Multikinaseinhibitoren in der Therapie des fortgeschrittenen Nierenzellkarzinoms

Due to the chemoresistance of renal cell cancer, cytokine-based therapeutic approaches were considered the standard treatment for patients with metastatic disease. At present, data that are available from a few phase II/III studies, dealing both with the first- and second-line treatment of patients suffering from systemic progression of RCC, indicate the significantly higher clinical efficacy of multikinase inhibitors when compared with cytokine-based therapeutic regimens. In this context, sorafenib (Nexavar, BAY 43-9006) and sunitinib (Sutent, SU 011248) are the most frequently applied and most intensively investigated substances. In Germany, with regard to a phase III study reported at the ASCO congress in 2006, sunitinib received approval for the first-line therapy of metastatic RCC. The application of multikinase inhibitors follows the principle of targeting such mediators that are considered to be substantially involved in the pathogenesis and particularly progression of renal cell cancer within relatively well-defined molecular pathways. The aim of the present paper is to address and to critically discuss the clinical data that are currently available regarding the therapeutic efficacy of kinase inhibitors during the treatment of metastatic RCC.

Do the Results of the New Trials Change the Standard Treatment of Metastatic Renal Cell Cancer?

With the emergence of novel angiogenesis inhibitors, we are moving to a new era for patients with metastasized renal cell carcinoma. Since the results achieved reflect more a modification of the natural course of the disease than a cure, past achievements should not be neglected. Low-risk patients with clear cell histology, especially those with pulmonary metastasis only, should still be offered cytokine therapy. For intermediate-risk patients sunitinib is the treatment of choice. For high-risk patients, temsirolimus has to date provided the most convincing data, its availability is however limited. Data with sorafenib and sunitinib in the high-risk group are still anecdotal. The toxicity profiles of these 2 drugs are different and might particularly relate to patients with known cardiovascular co-morbidity. No sufficient data are available regarding sequential use. After cytokine failure, sorafinib is the treatment of choice. Patients should preferably be treated within clinical trials to answer unaddressed questions. It is well known that the strict entry criteria used within the clinical studies were applied very flexibly when drugs have been approved. These aspects require a careful follow-up to ascertain optimal use and to prevent misuse. Finally, the costs of prolonged treatment will be enormous, and only meaningful survival advantages will convince the health authorities to make these new treatments available for all patients.

Two distinct types of blood vessels in clear cell renal cell carcinoma have contrasting prognostic implications

PURPOSE

Intratumoral microvascular density (MVD) has been controversial as an indicator of prognosis in clear cell renal cell carcinoma (CCRCC). Classification of the intratumoral blood vessels based on differential expressions of blood vessel markers has not been correlated with patient prognosis in CCRCC. In this study, we aimed to evaluate the association of different categories of blood vessels with the patients' outcomes.

EXPERIMENTAL DESIGN

Seventy-eight CCRCC patients who underwent nephrectomy alone were enrolled. Paraffin-embedded CCRCC tissues, together with 16 nonmalignant kidney cortex tissues, were used in tissue microarray analyses and conventional section analyses. The characteristics of intratumoral blood vessels were identified by multiple blood vessel markers and pericyte markers. A computerized image analysis program was used to quantitatively calculate the vascular density.

RESULTS

Two distinct types of microvessels were identified in CCRCC: undifferentiated (CD31(+)/CD34(-)) and differentiated (CD34(+)) vessels. A higher undifferentiated MVD significantly correlated with higher tumor grades and shorter patient survival. In contrast, a higher differentiated MVD significantly correlated with lower tumor grade and longer survival. Multivariate analyses showed that undifferentiated MVD was an independent prognostic factor for patient survival. An inverse correlation between undifferentiated MVD and differentiated MVD was also identified in CCRCC.

CONCLUSIONS

This is the first report showing distinct types of vasculature in CCRCC correlated with contrasting prognoses. A refined classification of CCRCC based on vasculature is therefore important for evaluating prognosis, and it may also have therapeutic implications.

Interferon-α Resistance Associated Genes in Renal Cell Carcinoma Identified by Expression Profiling

PURPOSE

We identified differentially expressed genes associated with response to pegylated interferon-alpha treatment in patients with renal cell carcinoma.

MATERIALS AND METHODS

We performed expression profiling on renal cell carcinoma specimens isolated from 23 patients with metastatic disease who were subsequently treated with interferon. Significance Analysis for Microarrays software was used to identify genes that were differentially expressed between patients with partial response compared to those with disease progression.

RESULTS

A candidate gene approach looking at VHL and known target genes did not identify any genes whose expression correlated with patient response. A global analysis of approximately 54,000 probe sets identified 4 genes that had expression correlated with response. Reverse transcriptase-polymerase chain reaction analysis of 2 of these genes confirmed that they were more highly expressed in tumors from patients who responded to interferon-alpha. Interestingly, both of these genes mapped to 4q31-32, a region that has been implicated as the site of a potential tumor suppressor gene in renal cell carcinoma.

CONCLUSIONS

We have identified 4 genes (3 uncharacterized and 1 known) that may prove useful in predicting response to interferon-alpha treatment in patients with renal cell carcinoma.

A review of the current clinical trials for gastroenteropancreatic neuroendocrine tumours

Neuroendocrine tumours of the gastroenteropancreatic axis include carcinoid tumours and islet cell tumours of the pancreas (pancreatic endocrine tumours). Standard medical therapies prescribed for these malignancies include long-acting somatostatin analogues (octreotide and lanreotide) for the palliation of hormonal syndromes; cytotoxic agents (streptozocin, dacarbazine, adriamycin and 5-fluorouracil), which are primarily for the management of advanced islet cell tumours; and hepatic artery embolisation or chemoembolisation for the treatment of liver metastases. Clinical research promises to expand this therapeutic armamentarium. Most of the experimental treatments that are being evaluated in human clinical trials fall into the following categories: angiogenesis inhibitors, novel somatostatin analogues, radiolabelled somatostatin analogues, mTOR inhibitors and novel cytotoxic agents. This review summarises the present scope of clinical research in this field.

Renal cell carcinoma guideline

OBJECTIVES

The European Association of Urology (EAU) Guideline Group for renal cell carcinoma (RCC) prepared this guideline to help urologists assess the evidence-based management of RCC and to incorporate the guideline recommendations into their clinical practice.

METHODS

The recommendations provided in the current guideline are based on a systematic literature search using MedLine, the Cochrane Central Register of Controlled Trials, and publications and review articles.

RESULTS

A limited number of prospective randomised studies are available with high-level evidence. Most publications concerning RCC are based on retrospective analyses, including some larger multicentre validation studies and well-designed controlled studies.

CONCLUSIONS

It must be stressed that the current guideline contains information for the treatment of an individual patient according to a standardised general approach. Updated recommendations concerning diagnosis, treatment, and follow-up can improve the clinical handling of patients with RCC.

ASCO 2006 highlights: targeted therapy for renal cell carcinoma

In the past few years, advances in the understanding of the pathogenesis of renal cell carcinoma (RCC) have resulted in the identification of new therapeutic targets, and ultimately, the development of new targeted agents for the treatment of the disease. This paper reviews latest data in RCC for the recently approved agents sunitinib and sorafenib, as well as other molecularly targeted drugs, presented at the annual meeting of the American Society for Clinical Oncology, held in Atlanta, Georgia, in June 2006. Clinical findings to date show that these new agents are challenging the role of cytokines in this setting, and for some (e.g. sunitinib) a substantially improved efficacy profile (progression-free survival and response) over conventional cytokine therapy has been reported. While challenges remain with regard to optimal use of these agents, the outlook for patients with advanced RCC has improved considerably and there is great hope for continuing progress.

Targeting von Hippel-Lindau pathway in renal cell carcinoma

Inheritance of a defective copy of the von Hippel-Lindau (VHL) gene leads to the most common cause of inherited renal cell carcinoma (RCC). In addition, most patients with sporadic RCC have aberrant VHL. In the absence of VHL, hypoxia-inducible factor alpha accumulates, leading to production of several growth factors, including vascular endothelial growth factor and platelet-derived growth factor. We review here the biology of RCC and how a combination of proximal and distal block of VHL/hypoxia-inducible factor alpha pathway by novel targeted agents, including sunitinib, sorafenib, bevacizumab, everolimus, and temsirolimus, has led to significant improvements in progression-free survival.

Forthcoming receptor tyrosine kinase inhibitors

Receptor tyrosine kinases play a significant role in carcinogenesis and have been successfully targeted with monoclonal antibodies and small-molecule inhibitors. There have been recent developments in the understanding of receptor tyrosine kinase signal transduction which have enabled better drug development. The use of receptor tyrosine kinase inhibitors in clinical practice has expanded the knowledge on cancer biology, in particular the understanding of resistant mutations and strategies to overcome such resistance. This has driven drug development from single kinase inhibitors to multi-kinase inhibitors and high-affinity kinase inhibitors. Finally, as the use of receptor tyrosine kinase inhibitors grows in clinical practice, more is learned about appropriate patient selection for such therapies. This is an exciting time in cancer therapeutics, highlighted by the advent of effective targeted therapy with receptor tyrosine kinase inhibitors.

Targeting vascular endothelial growth factor (VEGF)-receptor-signaling in renal cell carcinoma

Metastatic renal cell carcinoma (RCC) is resistant to conventional chemotherapy. Combined data for a variety of immunotherapies resulted in an overall chance of partial (PR) or complete remission (CR) of only 12.9%. There is a clear need for novel, more effective therapies to prevent relapse, control metastases and improve overall survival. Improved understanding of RCC disease biology has led to the introduction of molecularly targeted treatment strategies in these cancers. Von Hippel-Lindau (VHL) gene inactivation is observed in most clear cell renal carcinoma, resulting in vascular endothelial growth factor (VEGF) over-expression and driving the malignant phenotype. This review discusses the efficacy of novel therapies targeting the VEGF receptor (VEGFR) (e.g. anti-VEGF antibodies, VEGFR tyrosine kinase inhibitors, mTOR inhibitors), some of which were recently approved by the Food and Drug Administration/European Medicines Evaluation Agency (FDA/EMEA) and represent the new treatment standards in RCC patients.

Sunitinib

Sunitinib and its active metabolite (SU012662) are selective inhibitors of multiple receptor tyrosine kinases associated with tumour growth and angiogenesis. The clinical efficacy of oral sunitinib has been demonstrated in patients with advanced gastrointestinal stromal tumours (GIST). In a phase III, randomised, double-blind, placebo-controlled, multicentre trial in patients with metastatic and/or unresectable GIST following unsuccessful imatinib therapy, the median time to tumour progression and median progression-free survival time were > or =4-fold longer in patients receiving sunitinib 50 mg/day than in those receiving placebo, in 6-week cycles consisting of 4 weeks of treatment followed by a 2-week rest period. Sunitinib also exhibited antitumour activity in patients with advanced renal cell carcinoma (RCC) following unsuccessful cytokine therapy. In two multicentre, single-arm, phase II clinical trials in patients with cytokine-refractory metastatic RCC, partial responses were reported in 40% and 43% of patients receiving sunitinib 50 mg/day for 4 weeks followed by 2 weeks without treatment in 6-week cycles; 27% and 22% of patients achieved stable disease for > or =3 months. Sunitinib was more effective than interferon-alpha as a first-line therapy in patients with metastatic RCC. In a large, well designed, phase III trial in previously untreated patients, progression-free survival was significantly longer in patients receiving sunitinib 50 mg/day in 6-week cycles (4 weeks of treatment followed by a 2-week rest period) compared with those receiving interferon-alpha 9MU three times weekly (47.3 vs 24.9 weeks). In general, sunitinib was well tolerated in patients with GIST and RCC, with adverse events usually being of mild or moderate severity.

What Is Standard Initials Systemic Therapy in Metastatic Renal Cell Carcinoma?

Historically, systemic therapies for metastatic renal cell carcinoma RCC) have met with minimal success. Recently, an improved understanding of cancer biology has been translated into therapies that target pathways critical for RCC growth and survival and produce more robust clinical impact. The risks and benefits of several approaches to systemic therapy in metastatic RCC are reviewed. The need for chronic therapy of novel agents and potential for toxicity raise questions in regard to the timing of therapy and value of combination therapy over sequential single agents. Further insight into the biology of response, resistance, and toxicity is needed to allow for rational patient selection and enhanced application of systemic therapies. As new standard therapies for metastatic RCC emerge, clinical trial conduct remains a priority to further optimize patient outcome.