Salvage Therapy with Bevacizumab–Sunitinib Combination after Failure of Sunitinib Alone for Metastatic Renal Cell Carcinoma: A Case Series

Anti-angiogenic and antitumor effects of anlotinib combined with bevacizumab for colorectal cancer

BACKGROUND

The progression and metastasis of tumors are typically accompanied by angiogenesis. Crucially, vascular endothelial growth factor (VEGF) and its receptors (VEGFRs) play a significant role in tumor-associated angiogenesis. In this study, the aim was to investigate the antitumor effect of combining bevacizumab (Bev) with anlotinib (An) on colorectal cancer (CRC).

METHODS

The CCK-8 assay, EdU assay, and Annexin V staining were conducted to evaluate the proliferation and apoptosis of CRC cells in vitro. The migration capability of CRC cells and HUVECs was assessed using the Transwell assay. Additionally, the tube formation capability of HUVECs was investigated. Furthermore, the antitumor and antiangiogenic effects were evaluated in the BALB/c mice model using immunohistochemistry, TUNEL staining, and 18F-FDG PET/CT imaging. Finally, we analyzed the inhibitory effect of Bev and/or An on related signaling effectors through western blotting.

RESULTS

The in vivo CRC mice model revealed that the combination of Bev + An significantly suppressed tumor formation and angiogenesis. Bev + An inhibited tumor glucose metabolism and increased the median survival period in tumor-bearing mice. Mechanistically, the expressions of VEGF, VEGFR2, PDGFR, and FGFR, as well as the phosphorylation levels of AKT, were inhibited after Bev+An treatment. In conclusion, the dual vertical targeting of VEGF and VEGFR in the CRC mice model strongly inhibited tumor growth and angiogenesis, with the suppression of the AKT signaling pathway playing a partial role.

Characterisation of the Morphological, Functional and Molecular Changes in Sunitinib-Resistant Renal Cell Carcinoma Cells

Sunitinib resistance is a major clinical problem hampering the treatment of renal cell carcinoma (RCC). Studies on the comprehensive characterisation of morphological, functional and molecular changes in sunitinib-resistant RCC cells are lacking. The aim of the current study was to develop sunitinib resistance in four human RCC cell lines (786-0, Caki-1, Caki-2 and SN12K1), and to characterise the changed cell biology with sunitinib resistance. RCC cells were made resistant by continuous, chronic exposure to 10 μM of sunitinib over a period of 12 months. Cell proliferation, morphology, transmigration, and gene expression for interleukin-6 (IL-6), interleukin-8 (IL-8), vascular endothelial growth factor (VEGF), Bcl-2 and Bax were studied. There was no significant difference in growth rate or transmigration between the parental and resistant cells. Sunitinib-resistant cells were significantly hypertrophic compared with parental cells as evidenced by increases in the surface areas of the whole cells and the nuclei. IL-6 was significantly increased in all resistant cells. IL-8 was increased in sunitinib-resistant Caki-2 and SN12K1 cells and decreased in 786-0 without any significant changes in Caki-1. VEGF was increased in resistant Caki-2 and SN12K1 cells but not in 786-0 and Caki-1. The Bcl2/Bax ratio was increased in Caki-1, Caki-2 and SN12K1 cells but decreased in 786-0 cells. The increased IL-6 may contribute to sunitinib resistance either via VEGF-mediated angiogenesis or through shifting of the Bcl2/Bax balance in favour of anti-apoptosis.

Resistance to Targeted Therapies in Renal Cancer: The Importance of Changing the Mechanism of Action

Renal cell carcinoma (RCC) is a complex disease characterized by mutations in several genes. Loss of function of the von Hippel-Lindau (VHL) tumour suppressor gene is a very common finding in RCC and leads to up-regulation of hypoxia-inducible factor (HIF)-responsive genes accountable for angiogenesis and cell growth, such as platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF). Binding of these proteins to their cognate tyrosine kinase receptors on endothelial cells promotes angiogenesis. Promotion of angiogenesis is in part due to the activation of the phosphatidylinositol-3-kinase (PI3K)/AKT/mechanistic target of rapamycin (mTOR) pathway. Inhibition of this pathway decreases protein translation and inhibits both angiogenesis and tumour cell proliferation. Although tyrosine kinase inhibitors (TKIs) stand as the main first-line treatment option for advanced RCC, eventually all patients will become resistant to TKIs. Resistance can be overcome by using second-line treatments with different mechanisms of action, such as inhibitors of mTOR, c-MET, programmed death 1 (PD-1) receptor, or the combination of an mTOR inhibitor (mTORi) with a TKI. In this article, we briefly review current evidence regarding mechanisms of resistance in RCC and treatment strategies to overcome resistance with a special focus on the PI3K/AKT/mTOR pathway.

Sunitinib in kidney cancer: 10 years of experience and development

INTRODUCTION

Sunitinib is a multi-target, anti-angiogenic tyrosine kinase inhibitor and a key molecule in the treatment of metastatic renal cell carcinoma (mRCC). Since it first demonstrated its efficacy ten years ago, overall survival of mRCC has more than doubled, in part due to sunitinib. In most recent years, progress has been made in the comprehension of its mechanism of action and resistance. Areas Covered: In this article, clinical trials involving sunitinib in kidney cancer have been reviewed, defining its different indications in metastatic and localized RCC. The rationale of sunitinib's efficacy, preclinical trials, past-clinical trials and ongoing clinical trials are summarized. Dose and scheme base are discussed, as the recommended dosage is frequently not well tolerated. Combination therapies appear to be toxic. Novel immunotherapies are changing the landscape of mRCC treatment and challenging sunitinib. Special attention has been paid towards cancer cell biology and immunity involved in treatment response. Expert Commentary: Sunitinib's place in the therapeutic arsenal is being redefined with the arrival of major challengers. Dosage and scheduling of sunitinib remains a major challenge.

Sunitinib in the treatment of metastatic renal cell carcinoma

Sunitinib is an oral multi-targeted tyrosine kinase inhibitor (TKI) that targets various receptors, including vascular endothelial growth factor receptors (VEGFRs). Sunitinib received approval in 2006 and became a standard treatment option in the first-line treatment of metastatic renal cell cancer (mRCC) after a phase III trial showed superiority compared with interferon alpha (IFN-α). Sunitinib has also shown activity in second-line treatment in several trials. Most of the combination trials with sunitinib with various agents have led to considerable toxicity without improving efficacy. Sunitinib alone causes significant side effects and has a distinct profile with diarrhoea, hypertension, skin effects hypothyroidism, fatigue and nausea of special interest. The recommended dose of sunitinib in mRCC is 50 mg orally daily for 4 weeks, followed by 2 weeks off treatment (4/2 schedule). An alternative 2 weeks on, 1 week off schedule (2/1 schedule) seems to be of similar efficacy and better tolerability and could be more widely used in the future. An intermittent treatment strategy with a stop in remission and re-induction after progression showed efficacy in smaller trials and is currently being evaluated in a phase III trial. Direct comparison of sunitinib with pazopanib in first-line treatment showed a similar efficacy for both TKIs with a distinct toxicity profile. Data from two phase II trials showed that sunitinib has also activity in non-clear cell cancer and is an option due to a lack of better alternatives. Currently, after immune checkpoint inhibitors have shown very promising results in the second-line treatment of RCC, they are being tested in a number of phase III trials in the first-line setting. The future will show the position of sunitinib in the first-line treatment of RCC in the era of the immune checkpoint inhibitors.

The evolving role of monoclonal antibodies in the treatment of patients with advanced renal cell carcinoma: a systematic review

INTRODUCTION

While the majority of the vascular endothelial growth factor (VEGF) and mammalian target of rapamycin (mTOR) inhibitors currently used for the therapy of metastatic renal cell carcinoma (mRCC) are small molecule agents inhibiting multiple targets, monoclonal antibodies are inhibitors of specific targets, which may decrease off-target effects while preserving on-target activity. A few monoclonal antibodies have already been approved for mRCC (bevacizumab, nivolumab), while many others may play an important role in the therapeutic scenario of mRCC.

AREAS COVERED

This review describes emerging monoclonal antibodies for treating RCC. Currently, bevacizumab, a VEGF monoclonal antibody, is approved in combination with interferon for the therapy of metastatic RCC, while nivolumab, a Programmed Death (PD)-1 inhibitor, is approved following prior VEGF inhibitor treatment. Other PD-1 and PD-ligand (L)-1 inhibitors are undergoing clinical development.

EXPERT OPINION

Combinations of inhibitors of the PD1/PD-L1 axis with VEGF inhibitors or cytotoxic T-lymphocyte antigen (CTLA)-4 inhibitors have shown promising efficacy in mRCC. The development of biomarkers predictive for benefit and rational tolerable combinations are both important pillars of research to improve outcomes in RCC.

Sunitinib resistance in renal cell carcinoma

Of the many targeted therapies introduced since 2006, sunitinib has carved its way to become the most commonly used first-line therapy for the treatment of metastatic renal cell carcinoma (RCC). Despite significant improvements in progression-free survival, 30% of the patients are intrinsically resistant to sunitinib and the remaining 70% who respond initially will eventually become resistant in 6-15 months. While the molecular mechanisms of acquired resistance to sunitinib have been unravelling at a rapid rate, the mechanisms of intrinsic resistance remain elusive. Combination therapy, sunitinib rechallenge and sequential therapy have been investigated as means to overcome resistance to sunitinib. Of these, sequential therapy appears to be the most promising strategy. This mini review summarises our emerging understanding of the molecular mechanisms, and the strategies employed to overcome sunitinib resistance.

A phase I, open-label study of trebananib combined with sorafenib or sunitinib in patients with advanced renal cell carcinoma

BACKGROUND

Trebananib, an investigational peptibody, binds to angiopoietin 1 and 2, thereby blocking their interaction with Tie2.

PATIENTS AND METHODS

This open-label phase I study examined trebananib 3 mg/kg or 10 mg/kg intravenous (I.V.) once weekly plus sorafenib 400 mg twice per day or sunitinib 50 mg once per day in advanced RCC. Primary end points were adverse event incidence and pharmacokinetics.

RESULTS

Thirty-seven patients were enrolled. During trebananib plus sorafenib administration (n = 17), the most common treatment-related adverse events (TRAEs) included rash (n = 12; 71%), diarrhea (n = 12; 71%), hypertension (n = 11; 65%), and fatigue (n = 11; 65%); grade ≥ 3 TRAEs (n = 7; 41%); and 2 patients (12%) had peripheral edema. During trebananib plus sunitinib administration (n = 19), the most common TRAEs included diarrhea (n = 14; 74%), fatigue (n = 13; 68%), hypertension (n = 11; 58%), and decreased appetite (n = 11; 58%); grade ≥ 3 TRAEs (n = 13; 68%); and 8 (42%) patients had peripheral edema. Trebananib did not appear to alter the pharmacokinetics of sorafenib or sunitinib. No patient developed anti-trebananib antibodies. Objective response rates were 29% (trebananib plus sorafenib) and 53% (trebananib plus sunitinib).

CONCLUSION

The toxicities of trebananib 3 mg/kg or 10 mg/kg I.V. plus sorafenib or sunitinib in RCC were similar to those of sorafenib or sunitinib monotherapy, with peripheral edema being likely specific to the combinations. Antitumor activity was observed.

Combination therapy in metastatic renal cell cancer

The standard strategy in metastatic renal cell carcinoma (mRCC) is to use sequential treatment. Different pathways are known to be involved in the pathogenesis of mRCC and in the development of resistance to targeted drugs. Combinations of targeted drugs could theoretically achieve better inhibition of a given pathway, inhibition of different pathways, or inhibition of a pathway involved in the resistance to a given drug. However, there is as yet no clear evidence that combination therapy is of clinical benefit and excess toxicity has been observed. In mRCC the majority of studies have explored combinations of vascular endothelial growth factor (VEGF) inhibitors and mammalian target of rapamycin (mTOR) inhibitors. A new generation of VEGF tyrosine kinase inhibitors (TKIs) seems to be more tolerable, and therefore potentially easier to combine with other agents. Trials with PI3K/akt/mTORC1/2 inhibitor combinations and with other new targeted drugs are also ongoing.

Combination therapy for renal cell cancer: what are possible options?

Antiangiogenic therapy has shown promise in the treatment of patients with renal cell carcinoma (RCC). Two classes of antiangiogenic drugs, the anti-vascular endothelial growth factor antibody bevacizumab and the tyrosine kinase inhibitors sorafenib, sunitinib and pazopanib, have shown efficacy in patients with RCC and are approved by the US Food and Drug Administration for treatment of this cancer. In practice, the clinical benefit of antiangiogenic drugs in RCC has been heterogeneous, and in patients who do respond, benefits are modest and/or short-lived. To improve efficacy, combination targeted therapy has been attempted, but with either very limited additional efficacy or nontolerable toxicities. Recent advances in the molecular understanding of tumor angiogenesis and mechanism of resistance, along with the rapid development of targeted drug discovery, have made it possible to further explore novel combination therapy for RCC.

Temsirolimus and bevacizumab, or sunitinib, or interferon alfa and bevacizumab for patients with advanced renal cell carcinoma (TORAVA): a randomised phase 2 trial

BACKGROUND

Combining targeted treatments for renal cell carcinoma has been suggested as a possible method to improve treatment efficacy. We aimed to assess the potential synergistic or additive effect of the combination of bevacizumab, directed against the VEGF receptor, and temsirolimus, an mTOR inhibitor, in metastatic renal cell carcinoma.

METHODS

TORAVA was an open-label, multicentre randomised phase 2 study undertaken in 24 centres in France. Patients aged 18 years or older who had untreated metastatic renal cell carcinoma were randomly assigned (2:1:1) to receive the combination of bevacizumab (10 mg/kg every 2 weeks) and temsirolimus (25 mg weekly; group A), or one of the standard treatments: sunitinib (50 mg/day for 4 weeks followed by 2 weeks off; group B), or the combination of interferon alfa (9 mIU three times per week) and bevacizumab (10 mg/kg every 2 weeks; group C). Randomisation was done centrally and independently from other study procedures with computer-generated permuted blocks of four and eight patients stratified by participating centre and Eastern Cooperative Oncology Group performance status. The primary endpoint was progression-free survival (PFS) at 48 weeks (four follow-up CT scans), which was expected to be above 50% in group A. Analysis was by intention to treat. The study is ongoing for long-term overall survival. This study is registered with ClinicalTrials.gov, number NCT00619268.

FINDINGS

Between March 3, 2008 and May 6, 2009, 171 patients were randomly assigned: 88 to the experimental group (group A), 42 to group B, and 41 to group C. PFS at 48 weeks was 29.5% (26 of 88 patients, 95% CI 20.0-39.1) in group A, 35.7% (15 of 42, 21.2-50.2) in group B, and 61.0% (25 of 41, 46.0-75.9) in group C. Median PFS was 8.2 months (95% CI 7.0-9.6) in group A, 8.2 months (5.5-11.7) in group B, and 16.8 months (6.0-26.0) in group C. 45 (51%) of 88 patients in group A stopped treatment for reasons other than progression compared with five (12%) of 42 in group B and 15 (38%) of 40 in group C. Grade 3 or worse adverse events were reported in 68 (77%) of 88 patients in group A versus 25 (60%) of 42 in group B and 28 (70%) of 40 in group C. Serious adverse events were reported in 39 (44%) of 88, 13 (31%) of 42, and 18 (45%) of 40 patients in groups A, B, and C, respectively.

INTERPRETATION

The toxicity of the temsirolimus and bevacizumab combination was much higher than anticipated and limited treatment continuation over time. Clinical activity was low compared with the benefit expected from sequential use of each targeted therapy. This combination cannot be recommended for first-line treatment in patients with metastatic renal cell carcinoma.

FUNDING

French Ministry of Health and Wyeth Pharmaceuticals.

Targeted therapies for the treatment of metastatic renal cell carcinoma: clinical evidence

Although systemic therapy for patients with metastatic renal cell carcinoma (mRCC) was once limited to the cytokines interleukin-2 and interferon (IFN)-α, in recent years several targeted therapies have become available for first- and second-line use. These include sorafenib, sunitinib, bevacizumab (plus IFN-α), temsirolimus, everolimus, and, most recently, pazopanib. This expanded list of treatment options arose from molecular biological research that revealed aberrant signal transduction activities in RCC, enabling the identification of specific molecular targets for therapy. Molecular-targeted therapies have better efficacy and tolerability than cytokine therapy, and many are administered orally. The superior outcomes achieved with molecular-targeted agents are prompting investigators to reconsider overall survival as a primary endpoint in clinical trials, given the inherent complications of a required long duration of follow-up, a required large population, and confounding caused by crossover trial designs or effects of subsequent therapy after progression on the agent of interest. In mRCC trials, progression-free survival has become a popular primary endpoint and has served as the basis of approval for several targeted therapies. In addition to the identification of new agents, current research is focused on the evaluation of combination therapy with targeted agents. As more information regarding mechanisms of disease and drug resistance becomes available, new targets, new targeted agents, and new combinations will be studied with the goal of providing maximal efficacy with minimal toxicity. This article reviews the clinical evidence supporting the benefits of targeted agents in mRCC treatment, discusses survival endpoints used in their pivotal clinical trials, and outlines future research directions.

Prediction of progression-free survival rates after bevacizumab plus interferon versus interferon alone in patients with metastatic renal cell carcinoma: comparison of a nomogram to the Motzer criteria

BACKGROUND

The combination of bevacizumab plus interferon (BEV+IFN) for treatment of metastatic renal cell carcinoma (mRCC) is associated with improved progression-free survival (PFS) in a phase 3 study.

OBJECTIVE

To develop a novel model for prediction of individual PFS using data from the randomized, controlled phase 3 trial of BEV + IFN or interferon alone. The ability of the Motzer criteria for prediction of PFS was also assessed.

DESIGN, SETTING, AND PARTICIPANTS

Pretreatment parameters of 628 patients were included in the Cox regression model predicting PFS at 6, 12, 18, and 24 mo. BEV+IFN was administered to 337 patients; 291 patients received interferon alone. The developed model and the Motzer criteria were internally validated using Harrell's concordance index and calibrated.

RESULTS AND LIMITATIONS

Median PFS was 10.2 versus 4.6 mo (p < 0.001) for patients receiving BEV + IFN or interferon alone, respectively. The novel model relying on age, Karnofsky performance status, baseline albumin, alkaline phosphatase, and time from primary diagnosis to treatment resulted in the highest discrimination (area under the curve [AUC]: 72.8, 75.0, 72.8, and 70.8% at 6, 12, 18, and 24 mo). The AUC of the Motzer criteria risk groups was 63.7, 61.8, 58.6, and 51.8% for the same time points. Comparison of discriminatory ability between the developed model and the Motzer criteria showed statistically significant differences (all p ≤ 0.02). An external validation of the new model is warranted.

CONCLUSIONS

The developed model identified prognostic factors of PFS in mRCC patients treated with BEV+IFN or interferon alone and quantified individual risk of PFS. Relative to the Motzer criteria, the novel model demonstrated better discriminatory properties. The model may serve clinicians in identifying patients who can benefit the most from BEV+IFN versus interferon alone.