Sunitinib: Ten Years of Successful Clinical Use and Study in Advanced Renal Cell Carcinoma

Recent advances on anti-angiogenesis receptor tyrosine kinase inhibitors in cancer therapy

Angiogenesis has always been the topic of major scientific interest in the field of malignant tumors. Nowadays, targeting angiogenesis has achieved success in various carcinomas by several mechanisms, including the use of anti-angiogenic small molecule receptor tyrosine kinase inhibitors (TKIs). The development of TKIs targeting pro-angiogenic receptors, mainly vascular endothelial growth factor receptor (VEGFR) family, have significantly improved the outcome of certain types of cancers, like renal cell carcinoma, hepatocellular carcinoma, and colorectal carcinoma. However, the general response rate is not very satisfactory. The particular toxicity profile and resistance to anti-angiogenic targeted agents are unavoidable, and no specific marker is available to screen responsive patients to TKIs for precision therapy. To date, about 11 anti-angiogenic TKIs with different binding capacities to angiogenic receptor tyrosine kinase have been approved for the treatment of patients with advanced cancers. This review presents all approved anti-angiogenic small molecule receptor TKIs so far with an emphasis on their indications and clinical efficacy. We also discuss the combination between TKIs and immune checkpoint blockade inhibitors based on the most recent exciting outcome in immunotherapy.

Second-line treatment after sunitinib therapy in patients with renal cell carcinoma: a comparison of axitinib and mammalian target of rapamycin inhibitors

This retrospective study compared the outcomes of sequential therapy using sunitinib followed by axitinib or the mammalian target of rapamycin (mTOR) inhibitors (everolimus or temsirolimus). Among 234 patients treated with molecular-targeted drugs for metastatic renal cell carcinoma, we selected 137 patients treated with sunitinib as the first-line therapy. We then compared patients treated with axitinib (n = 52) or mTOR inhibitors (n = 31), as the second-line treatment, and investigated the progression-free survival (PFS) and overall survival (OS). The PFS of axitinib-treated patients (median 8.7 months) was superior to that of mTOR inhibitors-treated patients (median 3.4 months; P = 0.001). Additionally, the OS from baseline of axitinib-treated patients (median 69 months) was superior to that of mTOR inhibitors-treated patients (median 33.4 months; P = 0.034). A multivariate analysis was performed with the following factors: the drugs used for the second-line treatment, the Memorial Sloan Kettering Cancer Center risk classification during the initial treatment, whether the discontinuation of the first-line treatment was due to adverse events, and whether the duration of response of the first-line treatment was less than 6 or 12 months. Importantly, the drugs used for the second-line treatment and Memorial Sloan Kettering Cancer Center risk classification were independent factors. Our findings suggest that axitinib works better than mTOR inhibitors after the first-line treatment with sunitinib.

The difference in the survival rate of patients with metastatic renal cell carcinoma in the intermediate-risk group of the Memorial Sloan Kettering Cancer Center criteria

Objectives

To investigate the necessity of stratifying patients in the intermediate-risk group of the Memorial Sloan Kettering Cancer Center (MSKCC) criteria in a real-world population of patients with metastatic renal cell carcinoma.

Patients and Methods

We retrospectively analyzed 234 consecutively treated patients who had received molecular targeted drugs. We examined the difference between progression-free survival and overall survival among patients in the intermediate-risk group of MSKCC criteria. We divided the intermediate group into two subgroups as follows: patients positive for only one risk factor (Int-1) and those positive for two risk factors (Int-2) including performance status, serum hemoglobin level, time from diagnosis to treatment, and corrected calcium and lactate dehydrogenase levels. Next, we evaluated the association between the number of metastatic organs, the presence of pancreatic metastasis, Int-1 or Int-2 grouping, and overall survival.

Results

The median overall survival was 41.2 months. The median overall survival of the favorable-, intermediate-, and poor-risk groups of the MSKCC criteria were 91.0, 33.6, and 15.2 months, respectively. Patient characteristics were similar between the Int-1 and Int-2 groups. Increased positivity for risk factors of MSKCC classification between the two groups was for performance status and serum hemoglobin level. Progression-free survival and overall survival of the Int-1 group were significantly higher than those of the Int-2 group. In Cox proportional stepwise multivariate analysis, the Int-1 and Int-2 classification was an independent risk factor for overall survival.

Conclusion

Patients in the intermediate-risk group had different prognoses depending on the number of positive risk factors.

The tyrosine-kinase inhibitor sunitinib targets vascular endothelial (VE)-cadherin: a marker of response to antitumoural treatment in metastatic renal cell carcinoma

Background

Vascular endothelial (VE)-cadherin is an endothelial cell-specific protein responsible for endothelium integrity. Its adhesive properties are regulated by post-translational processing, such as tyrosine phosphorylation at site Y⁶⁸⁵ in its cytoplasmic domain, and cleavage of its extracellular domain (sVE). In hormone-refractory metastatic breast cancer, we recently demonstrated that sVE levels correlate to poor survival. In the present study, we determine whether kidney cancer therapies had an effect on VE-cadherin structural modifications and their clinical interest to monitor patient outcome.

Methods

The effects of kidney cancer biotherapies were tested on an endothelial monolayer model mimicking the endothelium lining blood vessels and on a homotypic and heterotypic 3D cell model mimicking tumour growth. sVE was quantified by ELISA in renal cell carcinoma patients initiating sunitinib (48 patients) or bevacizumab (83 patients) in the first-line metastatic setting (SUVEGIL and TORAVA trials).

Results

Human VE-cadherin is a direct target for sunitinib which inhibits its VEGF-induced phosphorylation and cleavage on endothelial monolayer and endothelial cell migration in the 3D model. The tumour cell environment modulates VE-cadherin functions through MMPs and VEGF. We demonstrate the presence of soluble VE-cadherin in the sera of mRCC patients (n = 131) which level at baseline, is higher than in a healthy donor group (n = 96). Analysis of sVE level after 4 weeks of treatment showed that a decrease in sVE level discriminates the responders vs. non-responders to sunitinib, but not bevacizumab.

Conclusions

These data highlight the interest for the sVE bioassay in future follow-up of cancer patients treated with targeted therapies such as tyrosine-kinase inhibitors.

Isatin, an endogenous nonpeptide biofactor: A review of its molecular targets, mechanisms of actions, and their biomedical implications

Isatin (indole-2,3-dione) is an oxidized indole. It is widely distributed in mammalian tissues and body fluids, where isatin concentrations vary significantly from <0.1 to > 10 µM. Isatin output is increased under conditions of stress. Exogenously administered isatin is characterized by low toxicity, mutagenicity, and genotoxicity in vivo. Cytotoxic effects of isatin on various cell cultures are usually observed at concentrations exceeding 100 µM. Binding of [³ H]isatin to rat brain sections is consistent with its physiological concentrations. Proteomic analysis of mouse and rat brain isatin-binding proteins revealed about 90 individual proteins, which demonstrated significant interspecies differences (rat versus mouse). Certain evidence exist that redox state(s) and possibly other types of posttranslational modifications regulate affinity of target proteins to isatin. Recent data suggest that interacting with numerous intracellular isatin binding proteins, isatin can act as a regulator of complex protein networks in norm and pathology. Physiological concentrations of isatin in vitro inhibit monoamine oxidase B and natriuretic peptide receptor guanylate cyclase, higher (neuroprotective) concentrations (50-400 μM) cause apoptosis of various (including malignant tumor) cell lines and influence expression of certain apoptosis-related genes. Being administered in vivo, isatin exhibits various behavioral effects; it attenuates manifestations of MPTP-induced parkinsonism and tumor growth in experimental animal models. © 2017 BioFactors, 44(2):95-108, 2018.

Expression of tyrosine kinase receptor AXL is associated with worse outcome of metastatic renal cell carcinomas treated with sunitinib

BACKGROUND

Renal cell carcinoma (RCC) represents 2%-3% of all cancers of the Western countries. Currently, sunitinib, a receptor tyrosine kinase inhibitor, particularly of PDGF and VEGF receptors, is the first-line therapy for metastatic RCC (mRCC), with significant improvement in clinical outcome. However, there is a lack of predictive biomarkers of sunitinib response. Recently, others and our group suggested that the receptor tyrosine kinase AXL may modify the response to sunitinib.

OBJECTIVE

To study the expression of AXL in a series patients with of mRCC treated with sunitinib and to correlate it with patient's clinic-pathological features and therapeutic response.

MATERIAL AND METHODS

Sixty-four patients with mRCC (51 clear cell carcinomas (CCCs) and 13 non-CCCs) were evaluated for AXL expression by immunohistochemistry in the primary tumor.

RESULTS

AXL positivity was observed in 47% (30/64) of cases, namely in 43% (22/51) of CCCs and 61% (8/13) of non-CCC. Considering only the clear cell subtype, the univariate analysis showed that AXL expression was statistically associated with a poor prognosis, with a median overall survival of 13 months vs. 43 months in patients with negative AXL. In this subtype, along with the AXL positivity, other prognostic factors were absence of nephrectomy, Karnofsky performance status, more than 1 site of metastasis and liver metastasis. Moreover, AXL expression was associated with shorter progression to sunitinib. Overall, the multivariate survival analysis showed that absence of nephrectomy (HR = 4.85, P = 0.001), more than 1 site of metastasis (HR = 2.99, P = 0.002), bone metastasis (HR = 2.95, P = 0.001), together with AXL expression (HR = 2.01, P = 0.048) were independent poor prognostic factor in patients with mRCC.

CONCLUSION

AXL expression was associated with worse clinical outcome and may be an important prognostic biomarker in sunitinib-treated patients with metastatic renal cell carcinoma.

Sex-Divergent Clinical Outcomes and Precision Medicine: An Important New Role for Institutional Review Boards and Research Ethics Committees

The efforts toward individualized medicine have constantly increased in an attempt to improve treatment options. These efforts have led to the development of small molecules which target specific molecular pathways involved in cancer progression. We have reviewed preclinical studies of sunitinib that incorporate sex as a covariate to explore possible sex-based differences in pharmacokinetics and drug–drug interactions (DDI) to attempt a relationship with published clinical outputs. We observed that covariate sex is lacking in most clinical outcome reports and suggest a series of ethic-based proposals to improve research activities and identify relevant different sex outcomes. We propose a deeper integration of preclinical, clinical, and translational research addressing statistical and clinical significance jointly; to embed specific sex-divergent endpoints to evaluate possible gender differences objectively during all stages of research; to pay greater attention to sex-divergent outcomes in polypharmacy scenarios, DDI and bioequivalence studies; the clear reporting of preclinical and clinical findings regarding sex-divergent outcomes; as well as to encourage the active role of scientists and the pharmaceutical industry to foster a new scientific culture through their research programs, practice, and participation in editorial boards and Institutional Ethics Review Boards (IRBs) and Research Ethics Committees (RECs). We establish the IRB/REC as the centerpiece for the implementation of these proposals. We suggest the expansion of its competence to follow up clinical trials to ensure that sex differences are addressed and recognized; to engage in data monitoring committees to improve clinical research cooperation and ethically address those potential clinical outcome differences between male and female patients to analyze their social and clinical implications in research and healthcare policies.