Second-line therapy for refractory renal-cell carcinoma

The role of pazopanib on tumour angiogenesis and in the management of cancers: A review

Pazopanib is a relatively new compound to be introduced into the chemotherapy field. It is thought to have decent anti-angiogenic properties, which gives an additional hope for the treatment of certain types of cancers. A systematic review solely discussing about pazopanib and its anti-angiogenic effect is yet to be published to date, despite several relevant clinical trials being conducted over the recent years. In this review, we aim to investigate the mechanism of pazopanib's anti-angiogenic effect and its effectiveness in treating several cancers. We have included, in this study, findings from electronically searchable data from randomized clinical trials, clinical studies, cohort studies and other relevant articles. A total of 352 studies were included in this review. From the studies, the effect of pazopanib in various cancers or models was observed and recorded. Study quality is indefinite, with a few decent quality articles. The most elaborately studied cancers include renal cell carcinoma, solid tumors, advanced solid tumors, soft tissue sarcoma, breast cancer and gynecological cancers. In addition, several less commonly studied cancers are included in the studies as well. Pazopanib had demonstrated its anti-angiogenic effect based on favorable results observed in cancers, which are caused by angiogenesis-related mechanisms, such as renal cell carcinoma, solid tumors, advanced solid tumors and soft tissue sarcoma. This review was conducted to study, analyze and review the anti-angiogenic properties of pazopanib in various cancers. The results obtained can provide a decent reference when considering treatment options for angiogenesis-related malignancies. Furthermore, the definite observations of the anti-angiogenic effects of pazopanib could provide newer insights leading to the future development of drugs of the same mechanism with increased efficiency and reduced adverse effects.

Suppression of mTOR pathway in solid tumors: lessons learned from clinical experience in renal cell carcinoma and neuroendocrine tumors and new perspectives

The PI3K-AKT-mTOR pathway plays role in the regulation of many cellular processes. Hyperactivation of mTOR signaling has been implicated in human carcinogenesis, representing an attractive target for cancer therapy. Among other cancer subtypes, renal cell carcinoma (RCC) and neuroendocrine tumors are relevant settings in which the deregulation of mTOR pathway is of crucial importance. Different mTOR-inhibitory agents have been developed in recent years. Temsirolimus is approved for advanced RCC; everolimus is registered for the treatment of advanced RCC, pancreatic neuroendocrine tumors and postmenopausal, hormone receptor-positive/HER2-negative, advanced breast cancer. This review is focused on the description of the clinical experience with mTOR-inhibitor agents for the treatment of advanced RCC and neuroendocrine tumors, followed by an excursus on the landscape of the ongoing research in this field.

The Role of Everolimus in Renal Cell Carcinoma

Everolimus (RAD001) is an orally administered agent that inhibits the mammalian target of rapamycin serine-threonine kinase. A phase III pivotal trial on everolimus, published in 2008, provided the first evidence for the efficacy of sequential therapy for patients with metastatic clear cell renal cell carcinoma (RCC). In this study, everolimus was used after failure of one or several previous lines of therapy, and it demonstrated a 3-month survival benefit relative to placebo. Currently, based on the level 1 evidence, everolimus represents the molecule of choice for third-line therapy after failure of previous two tyrosine kinase inhibitors (TKIs). However, second-line use after failure of one TKI is challenged by two new molecules (nivolumab and cabozantinib), which proved to have better efficacy with similar toxicity profile. In non-clear cell metastatic RCC, the current evidence recommends everolimus as a second-line therapy after failure of previous first-line sunitinib.

Multidisciplinary management of clear-cell renal cell carcinoma in Africa and the Middle East: current practice and recommendations for improvement

The management of renal cell carcinoma (RCC) has evolved considerably in recent years. This report represents the consensus of 22 relevant medical specialists from Africa and the Middle East region engaged in the management of RCC. Partial or radical nephrectomy is the standard of care for most patients with localized RCC. It is essential that patients are followed up appropriately after surgery to enable local and distant relapses to be identified and treated promptly. The treatment of advanced/metastatic disease has changed dramatically with the introduction of targeted therapies. Follow-up of these patients enables therapy optimization and assessment of response to treatment. There was universal agreement on the importance of management of RCC by a multidisciplinary team supported by a multidisciplinary tumor board. Barriers hindering this approach were identified. These included lack of awareness of the benefits of multidisciplinary team role, poor communication among relevant disciplines, time constraints, and specifics of private practice. Other challenges include shortage of expert specialists as urologists and oncologists and lack of local management guidelines in some countries. Solutions were proposed and discussed. Medical educational initiatives and awareness activities were highlighted as keys to encouraging cooperation between specialties to improve patients’ outcome. Establishing combined genitourinary cancer clinics and formal referral systems should encourage a culture of effective communication. Joining forces with professionals in peripheral areas and the private sector is likely to help standardize care. Sustained action will be required to ensure that all patients with RCC in the region benefit from up-to-date care.

Optimal first-line and second-line treatments for metastatic renal cell carcinoma: current evidence

Since 2005, an abundance of targeted agents has been approved for the treatment of metastatic renal cell carcinoma (mRCC), without any specification as to what may be the most optimal first-line and second-line sequence. Hence, our objective was to critically examine the evidence supporting the use of first-line and second-line agents in the management of mRCC. Our review suggests that in first line, sunitinib and pazopanib represent treatment options for patients with favorable or intermediate-risk features and clear cell histology. Unfortunately, the Phase III trial cannot conclusively prove the noninferiority of pazopanib relative to sunitinib. Hence, the use of sunitinib as first-line standard of care remains justified. Pazopanib represents an option for specific patients in whom sunitinib might not be tolerated. In patients with poor-risk features, temsirolimus represents the only option supported with level 1 evidence. Less optimal alternatives include sunitinib and bevacizumab combined with interferon, based on the minimal inclusion of poor-risk patients in pivotal Phase III studies of these two molecules. In patients with non-clear cell mRCC, the use of temsirolimus is supported by Phase III data, unlike for any other molecule. In second line, the options consist of everolimus and axitinib. However, the axitinib data are substantially more robust given the inclusion of more patients considered as true second-line, and validly justify the choice of axitinib over everolimus. Nonetheless, the Phase III trial of everolimus may be considered as level 1 evidence for use as third-line or subsequent lines of therapy.

PI3K/AKT signaling pathway and cancer: an updated review

Despite development of novel agents targeting oncogenic pathways, matching targeted therapies to the genetic status of individual tumors is proving to be a daunting task for clinicians. To improve the clinical efficacy and to reduce the toxic side effects of treatments, a deep characterization of genetic alterations in different tumors is required. The mutational profile often evidences a gain of function or hyperactivity of phosphoinositide 3-kinases (PI3Ks) in tumors. These enzymes are activated downstream tyrosine kinase receptors (RTKs) and/or G proteins coupled receptors (GPCRs) and, via AKT, are able to induce mammalian target of rapamycin (mTOR) stimulation. Here, we elucidate the impact of class I (p110α, β, γ, and δ) catalytic subunit mutations on AKT-mediated cellular processes that control crucial mechanisms in tumor development. Moreover, the interrelation of PI3K signaling with mTOR, ERK, and RAS pathways will be discussed, exploiting the potential benefits of PI3K signaling inhibitors in clinical use.

Everolimus as second-line therapy for metastatic renal cell carcinoma: a 'real-life' study

AIMS

This study, conducted in a 'field-practice' scenario, investigates the effectiveness and safety of everolimus in the second-line treatment of metastatic renal cell carcinoma (mRCC) patients.

PATIENTS & METHODS

mRCC patients, who started everolimus 10 mg/day after failure of first-line VEGF receptor-targeted tyrosine kinase inhibitor, were included in this study. Study end points were treatment response, progression-free survival and tolerability.

RESULTS

In total, 100 patients were assessed; the median duration of everolimus treatment was 7.1 months (95% CI: 5.7-8.5). A total of 19% of patients experienced a partial response and 62% of patients reached a stable disease. Median progression-free survival was 8 months (95% CI: 6.7-9.3). A total of 75% of patients experienced adverse events; no grade 4 adverse events were reported.

CONCLUSION

These findings, obtained in a 'field-practice' scenario, support the use of everolimus for mRCC patients who failed one VEGF receptor-targeted tyrosine kinase inhibitor.

Risk of gastrointestinal perforation in cancer patients treated with vascular endothelial growth factor receptor tyrosine kinase inhibitors: a systematic review and meta-analysis

BACKGROUND

The use of vascular-endothelial growth factor (VEGF) antibody bevacizumab is associated with an increased risk of gastrointestinal (GI) perforation, but the incidence and risk of GI perforation associated with vascular endothelial growth factor tyrosine-kinase inhibitors (VEGFR-TKIs) has not been well described. We conduct a systematic review and meta-analysis of published trials to evaluate the overall incidence and risk of GI perforation associated with VEGFR-TKIs.

METHODS

Databases from PubMed, Web of Science and abstracts presented at ASCO meeting up to March 31, 2013 were searched to identify relevant studies. Eligible studies included prospective phase II and III trials evaluating VEGFR-TKIs in cancer patients with adequate data on GI perforation. Statistical analyses were conducted to calculate the summary incidence, odds ratio (OR) and 95% confidence intervals (CIs) by using either random effects or fixed effect models according to the heterogeneity of included studies.

RESULTS

A total of 5352 patients with a variety of solid tumors from 20 clinical trials were included in our analysis. The incidence of GI perforation was 1.3% (95%CI: 0.8-2.0%) among patients receiving VEGFR-TKIs, with a mortality of 28.6% (15.0-47.6%). Patients treated with VEGFR-TKIs did not significantly increase the risk of GI perforation compared with patients treated with control medication, with an OR of 2.99 (95%CI: 0.85-10.53, p=0.089). Sub-group analysis showed that the incidence of GI perforation did not significantly vary with tumor types, VEGFR-TKIs and treatments regimens. No evidence of publication bias was observed.

CONCLUSIONS

The use of VEGFR-TKIs dose not significantly increase the risk of GI perforation in comparison with the controls. Further studies are recommended to investigate this association and the risk differences among different tumor types, VEGFR-TKIs or treatment regimens.

Down-regulation of CD74 inhibits growth and invasion in clear cell renal cell carcinoma through HIF-1α pathway

OBJECTIVES

To investigate the expression and function of CD74 in normal renal tissue and clear cell-renal cell carcinoma (ccRCC), as well as related renal tubule epithelial lines. We also analyzed the association between clinicopathological characteristics of ccRCCs and the expression levels of CD74.

METHODS

Immunostaining of CD74 was performed in 107 patients' renal tissue and cell lines. We evaluated the association between clinicopathological characteristics of ccRCC and CD74 levels using image analysis. CD74 expression levels were also analyzed by Western blot. Lentivirus-mediated CD74 knockdown inhibited the growth and invasion, of ccRCC cell lines 786-O in vitro and in vivo. Cell proliferation, apoptosis, and invasion as well as HIF-1α pathway-related proteins, were estimated by Western blot. All experiments were repeated at least 3 times.

RESULTS

Immunostaining and image analysis showed strong immunoreactions of CD74 in all patients' ccRCC tissue and malignant cell lines, while CD74 expression levels were associated with tumor grade (P = 0.013). Western blot indicated that ccRCC tissue and malignant cell lines expressed higher levels of CD74 and hypoxia inducible factor 1α (HIF-1α) than adjacent normal renal tissue and normal cell HK-2. Vitro and vivo tests demonstrated that lentivirus-mediated CD74 knockdown inhibited the proliferation of ccRCC cell lines, induced G1/S arrest and apoptosis, and inhibited invasion. Inhibition of CD74 resulted in down-regulation of HIF-1α pathway proteins.

CONCLUSIONS

CD74 was overexpressed in human ccRCCs and associated with tumor grade, and inhibition of CD74 produced ccRCC proliferation arrest, induced apoptosis, and inhibited invasion, which impinged on HIF-1α pathway-related proteins. It might represent a potential therapeutic target for ccRCC.

Experience with sorafenib in the treatment of advanced renal cell carcinoma

The molecular-targeted agent sorafenib is the first anticancer agent able to slow the progression of advanced/metastatic renal cell carcinoma, a tumor that was formerly refractory to conventional therapy. Experience from everyday clinical practice and investigations exploring the suitability of this agent for patients with harmful pathological conditions has extended the use of sorafenib to other settings of renal cell carcinoma and to particular risk populations. The aim of this review is to provide evidence on the most effective and safe use of sorafenib. The review pays particular attention to patients who have several comorbidities, such as impaired renal and cardiac function, and older patients whose frailty due to impaired organ function necessitates the most careful administration of targeted antineoplastic agents.