Efficacy of sequential therapies with sorafenib-sunitinib versus sunitinib-sorafenib in metastatic renal cell carcinoma: A systematic review and meta-analysis

Mechanisms of sunitinib resistance in renal cell carcinoma and associated opportunities for therapeutics

Sunitinib is the first-line drug for renal cell carcinoma (RCC) treatment. However, patients who received sunitinib treatment will ultimately develop drug resistance after 6-15 months, creating a huge obstacle to the current treatment of renal cell carcinoma. Therefore, it is urgent to clarify the mechanisms of sunitinib resistance and develop new strategies to overcome it. In this review, the mechanisms of sunitinib resistance in renal cell carcinoma have been summarized based on five topics: activation of bypass or alternative pathway, inadequate drug accumulation, tumour microenvironment, metabolic reprogramming and epigenetic regulation. Furthermore, present and potential biomarkers, as well as potential treatment strategies for overcoming sunitinib resistance in renal cell carcinoma, are also covered.

New frontiers against sorafenib resistance in renal cell carcinoma: From molecular mechanisms to predictive biomarkers

Renal cell carcinoma (RCC) is a highly vascularized tumor and prone to distant metastasis. Sorafenib is the first targeted multikinase inhibitor and first-line chemical drug approved for RCC therapy. In fact, only a small number of RCC patients benefit significantly from sorafenib treatment, while the growing prevalence of sorafenib resistance has become a major obstacle for drug therapy effectivity of sorafenib. The molecular mechanisms of sorafenib resistance in RCC are not completely understood by now. Herein, we comprehensively summarize the underlying mechanisms of sorafenib resistance and molecular biomarkers for predicting sorafenib responsiveness. Moreover, we outline strategies suitable for overcoming sorafenib resistance and prospect potential approaches for identifying biomarkers associated with sorafenib resistance in RCC, which contributes to guide individualized and precision drug therapy.

Improvement of Overall Survival Using TKIs as Salvage Therapy in Advanced Thyroid Carcinoma: Real-Life Data on a Single Center Experience

Background: Tyrosine kinase inhibitors (TKIs) have improved progression-free survival in patients with advanced thyroid cancer. So far, few studies have investigated the efficacy of TKIs in a second-line setting. The purpose of our study was to explore the salvage therapy efficacy in patients with advanced thyroid cancer. Methods: We retrospectively evaluated 63 patients with progressive advanced thyroid carcinoma treated with TKIs divided into a Study group (23 patients) treated with salvage therapy, and a Control group (40 patients) treated with only one TKI. Results: Similar clinical benefits (stable disease + partial response) and progression free survival between the first and the second line TKI were observed in the Study group (p > 0.99 and p = 0.5, respectively). Median overall survival (OS) was 67.7 months in the Study group and 22.6 months in the Control group (HR 2.46; 95% CI 1.34–4.52, p = 0.004). After stratifying the whole population by age (<65 and ≥65 years), OS was significantly different (p < 0.001) with the best survival curve in younger patients, treated with salvage therapy and the worst in older subjects, treated with only one TKI. Conclusions: Salvage therapy showed a significant improvement of OS in patients with advanced thyroid cancer who experienced disease progression during prior TKI therapies.

Molecular targeting of renal cell carcinoma by an oral combination

The 5-year survival rate of patients with metastatic renal cell carcinoma (mRCC) is <12% due to treatment failure. Therapeutic strategies that overcome resistance to modestly effective drugs for mRCC, such as sorafenib (SF), could improve outcome in mRCC patients. SF is terminally biotransformed by UDP-glucuronosyltransferase-1A9 (A9) mediated glucuronidation, which inactivates SF. In a clinical-cohort and the TCGA-dataset, A9 transcript and/or protein levels were highly elevated in RCC specimens and predicted metastasis and overall-survival. This suggested that elevated A9 levels even in primary tumors of patients who eventually develop mRCC could be a mechanism for SF failure. 4-methylumbelliferone (MU), a choleretic and antispasmodic drug, downregulated A9 and inhibited SF-glucuronidation in RCC cells. Low-dose SF and MU combinations inhibited growth, motility, invasion and downregulated an invasive signature in RCC cells, patient-derived tumor explants and/or endothelial-RCC cell co-cultures; however, both agents individually were ineffective. A9 overexpression made RCC cells resistant to the combination, while its downregulation sensitized them to SF treatment alone. The combination inhibited kidney tumor growth, angiogenesis and distant metastasis, with no detectable toxicity; A9-overexpressing tumors were resistant to treatment. With effective primary tumor control and abrogation of metastasis in preclinical models, the low-dose SF and MU combinations could be an effective treatment option for mRCC patients. Broadly, our study highlights how targeting specific mechanisms that cause the failure of “old” modestly effective FDA-approved drugs could improve treatment response with minimal alteration in toxicity profile.

Comparative efficacy and safety of sunitinib vs sorafenib in renal cell carcinoma: A systematic review and meta-analysis

To evaluate the safety and efficiency of sunitinib and sorafenib in the treatment of renal cell carcinoma (RCC).Databases were searched up till February 28, 2018. Two reviewers independently assessed trials for eligibility, quality, and extracted relevant data. Results are expressed as risk ratio (RR) or hazard ratio (HR) with 95% confidence intervals (CI). Six studies including 3112 patients were accessed. Sorafenib group exhibited higher median progression-free survival (mPFS) compared to sunitinib group (MD, -1.30; 95% CI, -2.56 to -0.03), especially in the first-line treatment (MD, -1.33; 95% CI, -2.61 to -0.04). However, sunitinib significantly reduced the risk of progression-free survival (PFS) compared to sorafenib (HR, 0.71; 95% CI, 0.6-0.82). Sunitinib also significantly reduced risk of overall survival (OS) compared to sorafenib (HR, 0.79; 95% CI, 0.65-0.92), while median OS was similar in both groups (MD, -0.48; 95% CI, -3.40-2.43). With regards to safety, the risk of rash (RR, 0.31, 95% CI, 0.12-0.79) was greater in sunitinib than sorafenib group, while the risk of decreased appetite (RR 2.10, 95% CI: 1.33-3.30) and dehydration (RR 2.73, 95% CI: 1.14-6.56) was smaller in contrast.Based on risk of PFS and OS, sunitinib was a better treatment option for RCC treatment while patients faced with severe skin reaction. And for those Asian patients classified under MSKCC moderate risk, whether in first or second-line treatment, had difficulty in feeding, sorafenib is a better choice for prolong mPFS.

Successful treatment with sorafenib for sunitinib-refractory metastatic papillary renal cell carcinoma: Potential impact of Raf overexpression on predicting the efficacy of sorafenib

Introduction

The prognosis of type 2 papillary renal cell carcinoma is often poor. We herein report a case of papillary renal cell carcinoma with liver metastasis that was successfully treated with sorafenib as a second‐line therapy.

Case presentation

An 82‐year‐old man who had undergone radical nephrectomy 5 years previously experienced biopsy‐proven liver metastasis. He received sunitinib as a first‐line treatment; the dose was initially 12.5 mg/day and was escalated to 25 mg/day, but it was discontinued due to several adverse events. We then switched to sorafenib as a second‐line treatment, which resulted in a partial response (51% reduction in tumor size); the patient showed no recurrence 5 months after the initiation of sorafenib treatment. An immunohistochemical analysis revealed the overexpression of Raf in both the primary and metastatic tumors.

Conclusion

As sorafenib blocks Raf signaling, the expression of Raf may serve as a useful predictor of the efficacy of sorafenib.

Cardiovascular diseases in patients receiving small molecules with anti-vascular endothelial growth factor activity: A meta-analysis of approximately 29,000 cancer patients

Background

Targeted therapy with tyrosine kinase inhibitors with anti-vascular endothelial growth factor activity improves survival of cancer patients. Cardiovascular complications are critical and it is unknown whether these require specific treatment strategies. We aimed to clarify the associated risk of cardiovascular adverse events in patients treated with tyrosine kinase inhibitors.

Design

The design of this study was a meta-analysis of randomised controlled trials.

Methods

We searched PubMed, Cochrane, EMBASE and Web of Science databases for randomised controlled trials published until January 2017 that assessed patients with different types of cancer treated with or without tyrosine kinase inhibitors in addition to standard chemotherapy.

Results

A total of 29,252 patients from 71 randomised controlled trials were included. Tyrosine kinase inhibitor treatment was associated with a higher cardiac ischaemia relative risk (relative risk = 1.69; 95% confidence interval: 1.12–2.57; p = 0.01), with the highest risks observed for sorafenib and patients with renal cancer. Risk of thrombocytopaenia (relative risk = 2.2; 95% confidence interval: 1.73–2.79; p < 0.001) was highest for regorafenib and patients with breast cancer. Left ventricular systolic dysfunction was increased after tyrosine kinase inhibitor therapy (relative risk = 2.53; 95% confidence interval:1.79 – 3.57; p < 0.001), with the highest risks reported for sunitinib and hepatocellular cancer. QT corrected interval prolongation (relative risk = 6.25; 95% confidence interval: 3.44–11.38; p < 0.001) and arterial hypertension (relative risk = 3.78; 95% confidence interval: 3.15-4.54; p < 0.001) were reported. The relative risks of arterial adverse events, cerebral ischaemia, venous adverse events and pulmonary embolism were similar across groups.

Conclusion

Tyrosine kinase inhibitors increase the risk of severe cardiovascular and particularly thrombotic adverse events. Specific treatment regimens when prescribing tyrosine kinase inhibitor therapies appear desirable.