Treatment outcomes of sunitinib treatment in advanced renal cell carcinoma patients: a single cancer center experience in Korea

pH-Responsive Block Copolymer Micelles of Temsirolimus: Preparation, Characterization and Antitumor Activity Evaluation

Purpose

Renal cell carcinoma (RCC) is the most common and lethal type of urogenital cancer, with one-third of new cases presenting as metastatic RCC (mRCC), which, being the seventh most common cancer in men and the ninth in women, poses a significant challenge. For patients with poor prognosis, temsirolimus (TEM) has been approved for first-line therapy, possessing pharmacodynamic activities that block cancer cell growth and inhibit proliferation-associated proteins. However, TEM suffers from poor water solubility, low bioavailability, and systemic side effects. This study aims to develop a novel drug formulation for the treatment of RCC.

Methods

In this study, amphiphilic block copolymer (poly(ethylene glycol) monomethyl ether-poly(beta-amino ester)) (mPEG-PBAE) was utilized as a drug delivery vehicle and TEM-loaded micelles were prepared by thin-film hydration method by loading TEM inside the nanoparticles. Then, the molecular weight of mPEG-PBAE was controlled to make it realize hydrophobic-hydrophilic transition in the corresponding pH range thereby constructing pH-responsive TEM-loaded micelles. Characterization of pH-responsive TEM-loaded nanomicelles particle size, potential and micromorphology while its determination of drug-loading properties, in vitro release properties. Finally, pharmacodynamics and hepatorenal toxicity were further evaluated.

Results

TEM loading in mPEG-PBAE increased the solubility of TEM in water from 2.6 μg/mL to more than 5 mg/mL. The pH-responsive TEM-loaded nanomicelles were in the form of spheres or spheroidal shapes with an average particle size of 43.83 nm and a Zeta potential of 1.79 mV. The entrapment efficiency (EE) of pH-responsive TEM nanomicelles with 12.5% drug loading reached 95.27%. Under the environment of pH 6.7, the TEM was released rapidly within 12 h, and the release rate could reach 73.12% with significant pH-dependent characteristics. In vitro experiments showed that mPEG-PBAE preparation of TEM-loaded micelles had non-hemolytic properties and had significant inhibitory effects on cancer cells. In vivo experiments demonstrated that pH-responsive TEM-loaded micelles had excellent antitumor effects with significantly reduced liver and kidney toxicity.

Conclusion

In conclusion, we successfully prepared pH-responsive TEM-loaded micelles. The results showed that pH-responsive TEM-loaded micelles can achieve passive tumor targeting of TEM, and take advantage of the acidic conditions in tumor tissues to achieve rapid drug release.

Prognostic and predictive significance of VEGF, CD31, and Ang-1 in patients with metastatic clear cell renal cell carcinoma treated with first-line sunitinib

The most common type of renal cell carcinoma (RCC) is clear cell renal cell carcinoma (ccRCC), which has a high metastatic potential. Even though the International Metastatic RCC Database Consortium (IMDC) risk model is conventionally utilized for selection and stratification of patients with metastatic RCC (mRCC), there remains an unmet demand for novel prognostic and predictive markers. The goal of this study was to analyze the expression of Vascular endothelial growth factor (VEGF), Cluster of Differentiation 31 (CD31) to determine microvessel density, and Angiopoietin-1 (Ang-1) in primary kidney tumors, as well as their predictive and prognostic value in patients with metastatic ccRCC (mccRCC) who were treated with first-line sunitinib. The study included 35 mccRCC patients who were treated with first-line sunitinib in period between 2009 and 2019. Immunofluorescence was used to examine biomarker expression in tissue specimens of the primary tumor and surrounding normal kidney tissue. Median disease-free survival (DFS) was longer in patients with negative and low tumor VEGF score than in patients with medium tumor VEGF score (p=0.02). Those with low tumor CD31 expression had a longer median DFS than patients with high tumor CD31 expression (p=0.019). There was no correlation between Ang-1 expression and DFS. The expression of biomarkers in normal kidney tissue was significantly lower than in tumor tissue (p<0.001). In conclusion, higher VEGF scores and greater CD31 expression were associated with longer DFS, but neither of these biomarkers correlated with progression-free survival or overall survival.

High levels of baseline serum IL-10 are associated with reduced clinical benefit from first-line immune checkpoint inhibitor therapy in advanced renal cell carcinoma

Immune checkpoint inhibitor (ICI) became a standard treatment for advanced renal cell carcinoma (RCC). However, clinically valid biomarkers of therapeutic outcome are lacking. We investigated the role of interleukin-10 (IL-10) as a predictive biomarker for first-line ICI therapy in patients with advanced RCC. Baseline serum samples were prospectively collected and analyzed using a cytometric bead assay. Patients were divided into two groups according to their serum IL-10 levels using maximally selected rank statistics. A fraction (13.0%) of patients had high levels of serum IL-10 at baseline. High serum IL-10 levels (> 4.3 ng/mL) were associated with a significantly shorter progression-free (median: 5.2 months vs. not reached, P = 0.007) and overall survival (median: 13.9 months vs. not reached, P < 0.001). Multivariate Cox regression analysis confirmed the independent association between high serum IL-10 levels and poor survival outcomes. Effector cytokine production and the proliferative response of CD8⁺ T cells were significantly lower in patients with high serum IL-10 levels, who also had a shorter duration of response to first-line ICI therapy (4.6 months vs. not reached, P < 0.001). In conclusion, elevated serum IL-10 levels at baseline were associated with reduced clinical benefit from first-line ICI therapy in patients with advanced RCC.

High Serum Levels of IL-6 Predict Poor Responses in Patients Treated with Pembrolizumab plus Axitinib for Advanced Renal Cell Carcinoma

Renal cell carcinoma (RCC) is the most common type of kidney malignancy worldwide with Pembrolizumab and axitinib treatment (Pembro/Axi) amongst the most effective first-line immunotherapies for advanced RCC. However, it remains difficult to predict treatment response and early resistance. Therefore, we evaluated whether baseline serum interleukin-6 (IL-6) could be a predictive biomarker. Between November 2019 and December 2021, 58 patients with advanced RCC were enrolled, administered first-line Pembro/Axi, and baseline blood samples were analyzed using flow cytometry. The mean baseline serum IL-6 concentration was 8.6 pg/mL in responders and 84.1 pg/mL in patients with progressive disease. The IL-6 cut-off value was set at 6.5 pg/mL using time-dependent receiver operating characteristic curves, with 37.9% of patients having high baseline serum IL-6 levels and 62.1% having low levels. Objective response rates were 58.3% and 36.4% in low and high IL-6 groups, respectively. Overall survival and progression-free survival were longer in patients with low IL-6 levels than in those with high levels. High IL-6 levels were related to reduced interferon-γ and tumor necrosis factor-α production from CD8+ T cells. Overall, high baseline serum IL-6 levels were associated with worse survival outcomes and reduced T-cell responses in Pembro/Axi-treated advanced RCC patients.

Comparative Evaluation of Safety and Efficacy of Alternate Schedule (AS) of Sunitinib in Asian and Non-Asian Patient Population for the Treatment of Metastatic Renal Cell Cancer (mRCC): A Meta-Analysis

Background: Treatment of metastatic renal cell carcinoma (mRCC) using traditional schedule (TS, 4/2) of Sunitinib is associated with higher adverse effects compared to the alternate schedule (AS, 2/1 upfront or when switched from TS). Objective: This meta-analysis aims to compare the safety, efficacy, and percentage of patients requiring dose reduction or dose interruption between Asian (AP) and non-Asian population (NAP) receiving AS of sunitinib. Methods: Electronic databases (PubMed, EMBASE, Cochrane Library) were searched to identify studies published in the English language between May 2009- May 2019, which included patients (>18 years) with mRCC receiving AS of sunitinib. Data were analyzed using the random effect model and t-test. P <  0.05 was considered statistically significant. Results: Of 1922, 16 studies were included (eight AP, eight NAP). Among all grade AEs, mucositis (RR:0.22; 95% CI:0.12–0.40), cardiotoxicity (RR: 0.52; 95% CI: 0.31–0.88), nausea (RR:0.21; 95% CI: 0.10–0.44), hand-foot syndrome (RR:0.33; 95% CI:0.13–0.83), rash (RR: 0.52; 95% CI: 0.34–0.79), and aspartate transaminase (RR:0.57; 95% CI:0.33–0.98) were more common in AP. Leukopenia (RR:2.57; 95% CI:1.47–4.49), proteinemia (RR:4.45; 95% CI:2.12–9.33), and stomatitis (RR:4.33; 95% CI:2.6–7.23) occurred more commonly in NAP. Further, PFS was significantly longer in NAP, while longer OS was observed in AP (p <  0.001). Dose reduction was significantly higher in AP than NAP (52.08% vs. 40.6%, p = 0.0088). Conclusion: Safety profile of AS of sunitinib was similar with variations in the efficacy, dose reduction between AP and NAP. Sunitinib dose or schedule modification may mitigate AEs and enhance efficacy outcomes in mRCC by extending the treatment duration.

Prognostic factors for overall survival in patients with clear cell metastatic renal cell carcinoma: Model development and external validation with Memorial Sloan Kettering Cancer Center model and the international metastatic renal cell carcinoma database consortium model

To develop a new prognostic model for the overall survival of patients with clear cell metastatic renal cell carcinoma (mRCC) using Korean Renal Cancer Study Group (KRoCS) database and compared it with 2 renowned prognostic models: the Memorial Sloan Kettering Cancer Center (MSKCC) and the international metastatic renal cell carcinoma database consortium (IMDC) models.Data of 790 patients diagnosed with mRCC and receiving targeted therapy as their first-line treatment were pooled to this study. Data from 4 hospitals (n = 619) were used to develop the new model and those from other 5 hospitals (n = 171) were used for external validation. After detecting prognostic factors in multivariable Cox proportional-hazards regression analysis, patients were classified into 3 risk groups, favorable (0), intermediate (1-2), and poor (3 and more) by the number of prognostic factors.Seven variables such as more than 2 metastasis sites, no prior nephrectomy, Eastern Cooperative Oncology Group performance status ≥2, low hemoglobin, high serum corrected calcium, high neutrophil, high serum alkaline phosphatase were identified as prognostic factors for poor overall survival. Also, risk groups were categorized into 3 groups; median overall survival was 61.1 months in favorable, 26.5 months in intermediate, and 6.8 months in poor group. KRoCS ranked the first in all 3 statistical parameters including akaike information criterion (AIC), concordance index and generalized R2 among other prognostic models.We developed the KRoCS model and validated it externally with demonstrating its superiority over MSKCC and IMDC models. The KRoCS model can provide useful information for counseling patients with clear cell mRCC regarding life-expectancy.

Avelumab plus axitinib vs sunitinib for advanced renal cell carcinoma: Japanese subgroup analysis from JAVELIN Renal 101

The phase 3 JAVELIN Renal 101 trial of avelumab + axitinib vs sunitinib in patients with treatment-naive advanced renal cell carcinoma (RCC) demonstrated significantly improved progression-free survival (PFS) and higher objective response rate (ORR) with the combination vs sunitinib. Japanese patients enrolled in the study (N = 67) were randomized to receive avelumab + axitinib (N = 33) or sunitinib (N = 34); 67% vs 59% had PD-L1+ tumors (≥1% of immune cells) and 6%/64%/27% vs 6%/82%/12% had International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) favorable/intermediate/poor risk status. In patients who received avelumab + axitinib vs sunitinib, median PFS (95% confidence interval [CI]) was not estimable (8.1 months, not estimable) vs 11.2 months (1.6 months, not estimable) (hazard ratio [HR], 0.49; 95% CI, 0.152, 1.563) in patients with PD-L1+ tumors and 16.6 months (8.1 months, not estimable) vs 11.2 months (4.2 months, not estimable) (HR, 0.66; 95% CI, 0.296, 1.464) in patients irrespective of PD-L1 expression. Median overall survival (OS) has not been reached in either arm in patients with PD-L1+ tumors and irrespective of PD-L1 expression. ORR (95% CI) was 60.6% (42.1%, 77.1%) vs 17.6% (6.8%, 34.5%) in patients irrespective of PD-L1 expression. Common treatment-emergent adverse events (all grade; grade ≥3) in each arm were hand-foot syndrome (64%; 9% vs 71%; 9%), hypertension (55%; 30% vs 44%; 18%), hypothyroidism (55%; 0% vs 24%; 0%), dysgeusia (21%; 0% vs 56%; 0%) and platelet count decreased (3%; 0% vs 65%; 32%). Avelumab + axitinib was efficacious and tolerable in treatment-naive Japanese patients with advanced RCC, which is consistent with results in the overall population.

Efficacy and Prognostic Factors of Sunitinib as First-Line Therapy for Patients With Metastatic Renal Cell Carcinoma in an Arab Population

PURPOSE

Antiangiogenic tyrosine kinase inhibitors have been the mainstay first-line therapy for metastatic renal cell carcinoma (mRCC). We reviewed the efficacy of first-line therapy with sunitinib in patients with mRCC in an Arab population.

METHODS

Medical records of patients with mRCC treated at a tertiary care center in Saudi Arabia, during the period from 2007 to 2016, were reviewed. Demographic data, treatment received, response, and prognostic factors were analyzed.

RESULTS

Fifty-five patients who received sunitinib were identified. The median age was 60 years (range, 18 to 78 years), and 42 of the 55 patients were men (76.3%). International Metastatic RCC Diagnostic Consortium prognostic scores for favorable/intermediate/poor were 14.5%/43.6%/38.2%, respectively. The median performance status was 1, and the median Charlson comorbidity index score was 9. Thirty-seven patients (67.2%) had cytoreductive nephrectomy. Thirty-seven patients (67.2%) had clear cell histology. Twenty-two patients (40%) underwent dose reduction. Twenty-seven patients (49%) received second-line therapy, and seven patients (12.7%) received third-line therapy. Response rates were complete response in one patient (1.8%), partial response in 17 (30.9%), stable disease in 10 (18.1), and disease progression in 20 (36.3%). Progression-free survival (PFS) and overall survival (OS) were 6.0 and 24.7 months, respectively. Univariate analysis showed statistically improved PFS for dose reduction (P = .015) and the development of hypothyroidism (P = .03). It also showed statistically improved OS for dose reduction (P = .035), hypothyroidism (P = .0002), and cytoreductive nephrectomy (P = .0052). Multivariate analysis showed statistically improved PFS for dose reduction (P = .01) and OS for development of hypothyroidism (P = .007).

CONCLUSION

Our data for sunitinib in mRCC show significantly lower PFS than expected. The absence of prognostic value of the International Metastatic RCC Diagnostic Consortium scoring system and pathologic subtype warrant further investigation and possible inclusion of genetic scoring in this ethnic group of patients.

Temsirolimus in Asian Metastatic/Recurrent Non-clear Cell Renal Carcinoma

PURPOSE

Temsirolimus is effective in the treatment for metastatic non-clear cell renal cell carcinoma (nccRCC) with poor prognosis. We aim to investigate the efficacy and tolerability of temsirolimus in treatment of naïve Asian patients with metastatic/recurrent nccRCC.

MATERIALS AND METHODS

From January 2008 to July 2017, data of treatment-naïve, metastatic/recurrent nccRCC patients, who were treated with temsirolimus according to the standard protocol, were collected. The primary end-point was progression-free survival (PFS). Secondary end points were overall survival (OS), objective response rate (ORR), and tolerability of temsirolimus.

RESULTS

Forty-four metastatic/recurrent nccRCC patients, 10 from prospective and 34 from retrospective groups, were enrolled; 24 patients (54%) were papillary type, and other histology subtypes included 11 chromophobes (25%), two collecting ducts (5%), one Xp11.2 translocation (2%), and six others (14%). The median PFS and OS were 7.6 months and 17.6 months, res-pectively. ORR was 11% and disease control rate was 83%. Patients with prior nephrectomy had longer PFS (hazard ratio [HR], 0.16; 95% confidence interval [CI], 0.06 to 0.42; p < 0.001) and OS (HR, 0.15; 95% CI, 0.05 to 0.45; p < 0.001). Compared to favorable/intermediate prognosis group, poor prognosis group had shorter median PFS (4.7 months vs. 7.6 months [HR, 2.91; 95% CI, 1.39 to 6.12; p=0.005]) and median OS (9.2 months vs. 17.6 months [HR, 2.84; 95% CI, 1.23 to 6.56; p=0.015]).

CONCLUSION

Temsirolimus not only benefits poor-risk nccRCC patients, but it is also effective in favorable or intermediate-risk group in Asians. Temsirolimus was well-tolerated with manageable adverse events.

The Roles of Common Variation and Somatic Mutation in Cancer Pharmacogenomics

Cancer pharmacogenomics is the science concerned with understanding genetic alterations and its effects on the pharmacokinetics and pharmacodynamics of anti-cancer drugs, with the aim to provide cancer patients with the precise medication that will achieve a good response and cause low/no incidence of adverse events. Advances in biotechnology and bioinformatics have enabled genomic research to evolve from the evaluation of alterations at the single-gene level to studies on the whole-genome scale using large-scale genotyping and next generation sequencing techniques. International collaborative efforts have resulted in the construction of databases to curate the identified genetic alterations that are clinically significant, and these are currently utilized in clinical sequencing and liquid biopsy screening/monitoring. Furthermore, countless clinical studies have accumulated sufficient evidence to match cancer patients to therapies by utilizing the information of clinical-relevant alterations. In this review we summarize the importance of germline alterations that act as predictive biomarkers for drug-induced toxicity and drug response as well as somatic mutations in cancer cells that function as drug targets. The integration of genomics into the medical field has transformed the era of cancer therapy from one-size-fits-all to cancer precision medicine.

First-line axitinib versus sorafenib in Asian patients with metastatic renal cell carcinoma: exploratory subgroup analyses of Phase III data

AIM

Efficacy/safety of first-line axitinib in Asian patients with metastatic renal cell carcinoma.

METHODS

Patients were assigned (2:1) to 5-mg axitinib (n = 48) or 400-mg sorafenib (n = 24) twice daily. Primary end point was progression-free survival. Objective response rate, overall survival and adverse events were also assessed.

RESULTS

For axitinib versus sorafenib, hazard ratio for progression-free survival was 0.652 (95% CI: 0.340-1.252; p = 0.0989), objective response rate was higher (35.4 vs 16.7%; p = 0.0495), overall survival longer (hazard ratio: 0.739; 95% CI: 0.397-1.375; p = 0.1683). Palmar-plantar erythrodysesthesia (57.4%), diarrhea (55.3%), hypertension (51.1%) were commonest adverse events with axitinib; palmar-plantar erythrodysesthesia (50.0%) with sorafenib.

CONCLUSION

Axitinib improved efficacy in Asian patients with metastatic renal cell carcinoma; adverse events were consistent with previous findings.

Stomatitis and VEGFR-Tyrosine Kinase Inhibitors (VR-TKIs): A Review of Current Literature in 4369 Patients

Background

Multitargeted tyrosine kinase inhibitors (TKIs) represent a new class of target-specific antineoplastic agents. These agents show some specific adverse events such as fatigue/asthenia, anorexia/loss of appetite, dysgeusia, diarrhea/abdominal pain, hypothyroidism, hypertension, myelosuppression, and stomatitis.

Materials and Methods

A systematic search was performed on PubMed online database using a combination of MESH terms and free text words, “sunitinib” OR “sorafenib” OR “axitinib” OR “cabozantinib” OR “pazopanib” OR “regorafenib” OR “nintedanib” OR “vatalanib” combined through the use of Boolean operator AND with the key words “stomatitis” OR “mucositis,” (i) on human subjects, (ii) written in the English language, and (iii) reporting about the incidence of stomatitis or oral mucositis.

Results

The incidence of stomatitis of any grade was 35.2% for sunitinib, 20.52% for sorafenib, 20.63% for axitinib, and 34.21% for cabozantinib. All the agents showed high rates of low-grade stomatitis (G1-G2), while the onset of severe stomatitis (G3-G4) was very low.

Conclusions

Analysis of the reports with patients treated with sunitinib, sorafenib, axitinib, and cabozantinib showed a clear prevalence of stomatitis grade 1 or grade 2. These data differ from those of patients treated with conventional chemotherapy in which mucositis is predominantly of grade 3 or grade 4.

miR‑660‑5p is associated with cell migration, invasion, proliferation and apoptosis in renal cell carcinoma

Renal cell carcinoma (RCC) is a common malignant tumor of the urinary system with poor prognosis. microRNAs (miRNAs) are a class of small, non‑coding RNA molecules that serve important roles in biological and pathological processes in several types of human tumors. miRNA (miR)‑660‑5p is dysregulated in many human cancers; however, its role in renal cell carcinoma is currently unclear. In the present study, reverse transcription‑quantitative polymerase chain reaction was performed to examine the expression levels of miR‑660‑5p in RCC tissues and paired normal adjacent tissues (NATs). To determine the function of miR‑660‑5p in RCC cells, wound‑healing and Matrigel assays were performed to determine the effects of miR‑660‑5p on cell migration and invasion, respectively. MTT and Cell Counting kit‑8 assays were performed to determine the effects of miR‑660‑5p on RCC cell proliferation. In addition, flow cytometric analysis was performed to validate the effects of miR‑660‑5p on apoptosis. The results indicated that miR‑660‑5p expression was downregulated in RCC tissues compared with NATs. Restoration of miR‑660‑5p expression using synthetic mimics may suppress cell migration, invasion and proliferation, and induce cell apoptosis, while using synthetic inhibitors may promote cell migration, invasion and proliferation, and suppress cell apoptosis. These results suggested that miR‑660‑5p may serve a tumor suppressive role in RCC tumorigenesis.

Oncogenic miR-100-5p is associated with cellular viability, migration and apoptosis in renal cell carcinoma

As influencing factors of genesis and progression in several types of human tumor, microRNAs (miRs) serves roles in the regulation of tumor cell viability, migration, and apoptosis. The present research aimed to investigate the association between the function of miR‑100‑5p and renal cell carcinoma (RCC). miR‑100‑5p expression was determined in RCC tissue and paired normal tissue samples using reverse transcription‑quantitative polymerase chain reaction. To assess the effects of miR‑100‑5p on cell viability, migration and apoptosis, multiple methods were used, including scratch wound assays, MTT assays, and flow cytometry. It was demonstrated that miR‑100‑5p was significantly upregulated in RCC tissue compared with in normal adjacent tissue samples. Furthermore, the viability and migration of 786‑O and, ACHN cells tranfected with miR‑100‑5p was significantly increased compared with the negative control group. In addition, miR‑100‑5p‑transfected 786‑O and ACHN cells demonstrated significantly reduced cellular apoptotic rates compared with the negative control group. To the best of our knowledge, the present study is the first to report an association between miR‑100‑5p and RCC. The results of the current study suggest that tumor oncogene miR‑100‑5p could be used as a diagnostic biomarker for RCC.

Sunitinib treatment in patients with advanced renal cell cancer: the Brazilian National Cancer Institute (INCA) experience

Purpose:

The aim of this study was to assess the impact of sunitinib treatment in a non-screened group of patients with metastatic renal cell cancer (mRCC) treated by the Brazilian Unified Health System (SUS) at a single reference institution.

Material and Methods:

Retrospective cohort study, which evaluated patients with mRCC who received sunitinib between May 2010 and December 2013.

Results:

Fifty-eight patients were eligible. Most patients were male 41 (71%), with a median age of 58 years. Nephrectomy was performed in 41 (71%) patients with a median interval of 16 months between the surgery and initiation of sunitinib. The most prevalent histological subtype was clear cell carcinoma, present in 52 (91.2%) patients. In 50 patients (86%), sunitinib was the first line of systemic treatment. The main adverse effects were fatigue (57%), hypothyroidism (43%), mucositis (33%) and diarrhea (29%). Grade 3 and 4 adverse effects were infrequent: fatigue (12%), hypertension (12%), thrombocytopenia (7%), neutropenia (5%) and hand-foot syndrome (5%). Forty percent of patients achieved a partial response and 35% stable disease, with a disease control rate of 75%. Median progression free survival was 7.6 months and median overall survival was 14.1 months.

Conclusion:

Sunitinib treatment was active in the majority of patients, especially those with low and intermediate risk by MSKCC score, with manageable toxicity. Survival rates were inferior in this non-screened population with mRCC treated in the SUS.

Assessment of ethnic differences in sunitinib outcome between Caucasian and Asian patients with metastatic renal cell carcinoma: a meta-analysis

BACKGROUND

An increasing number of studies have reported ethnic differences in sunitinib outcome in metastatic renal cell carcinoma (mRCC) patients. However, a comprehensive analysis is still lacking. Therefore, we systematically collected available published data and performed a meta-analysis to compare sunitinib efficacy and toxicity in Asian and Caucasian mRCC patients.

METHODS

Data were extracted from published results from clinical trials, expanded access program and real-world clinical practice. Progression-free survival (or time to tumor progression), overall survival, objective response rate and adverse events were used as endpoints to evaluate the differences of sunitinib outcome between the two ethnicities. For adverse events, we focused the following clinically relevant side effects: diarrhea, fatigue, mucositis/stomatitis, hand-foot syndrome, hypertension, leukopenia, neutropenia and thrombocytopenia.

RESULTS

A total of 33 publications including 9977 patients were available for meta-analysis. The efficacy of sunitinib in Asian patients was similar to that in Caucasian patients. However, Asian patients showed a higher incidence of all grades toxicity of hand-foot syndrome, > grade 2 fatigue, > grade 2 hand-foot syndrome and > grade 2 thrombocytopenia.

CONCLUSION

Ethnic differences in adverse events of sunitinib in mRCC patients existed and dose adjustment in Asian patients may be considered.

Key predictive factors for efficacy of axitinib in first-line metastatic renal cell carcinoma: subgroup analysis in Japanese patients from a randomized, double-blind phase II study

OBJECTIVES

To conduct Japanese subgroup analyses of a randomized, global Phase II study of axitinib with and without dose titration in first-line metastatic renal cell carcinoma and to explore predictive factors for axitinib efficacy in first-line metastatic renal cell carcinoma.

METHODS

The data included 44 Japanese and 169 non-Japanese treatment-naïve patients with metastatic renal cell carcinoma. Patients received twice-daily axitinib 5 mg during a 4-week lead-in period. Patients who met the pre-defined randomization criteria were stratified by Eastern Cooperative Oncology Group performance status and randomly assigned (1:1) to axitinib or placebo titration. The primary endpoint was objective response rate; secondary endpoints included progression-free survival and safety. Predictive factors were analyzed using data from all patients.

RESULTS

The objective response rate (95% confidence interval) was 66% (50-80%) vs. 44% (36-52%) in Japanese and non-Japanese patients, respectively. At the primary analysis, median progression-free survival could not be estimated for Japanese patients, and was 27.6 months (95% confidence interval: 16.6-33.2) in an updated analysis. Hypertension, diarrhea, hand-foot syndrome, dysphonia, hypothyroidism and proteinuria were common adverse events in Japanese patients. Due to a small number of randomized patients, effects of axitinib dose titration could not sufficiently be confirmed among Japanese patients. The multivariate analysis identified time from histopathological diagnosis to treatment and sum of the longest diameter for target lesion at baseline as independent predictive factors for progression-free survival.

CONCLUSIONS

Axitinib is effective and well tolerated as first-line metastatic renal cell carcinoma therapy in Japanese patients. Predictive factors for axitinib efficacy endpoints identified in this setting warrant further investigation.

Sunitinib: the antiangiogenic effects and beyond

As a multitargeted kinase inhibitor, sunitinib has carved its way into demonstrating itself as a most effective tyrosine kinase inhibitor in the treatment of metastatic renal cell carcinoma. Mechanistically, sunitinib inhibits multiple receptor tyrosine kinases, especially those involved in angiogenesis, that is, vascular endothelial growth factor receptor, platelet-derived growth factor receptor, and proto-oncogene cKIT. Sunitinib has also been implicated in enhancing cancer invasiveness and metastasis. Mechanisms of resistance are poorly understood, but both intrinsic and acquired mechanisms are thought to be involved. While the side effects are manageable, sunitinib, like many other tyrosine kinase inhibitors, can be associated with serious toxicities that require careful management including frequent dose reductions. Although still in the early stage, emerging evidence points to an immunomodulatory role for sunitinib. It is also likely to contribute to the overall outcomes, especially those seen in metastatic renal cell carcinoma, and such effects are thought to be mediated by the proto-oncogene cKIT receptor. Combination with other modalities such as stereotactic body radiation therapy, therapeutic vaccines, and checkpoint inhibitors is being pursued for improved efficacy.

BSA and ABCB1 polymorphism affect the pharmacokinetics of sunitinib and its active metabolite in Asian mRCC patients receiving an attenuated sunitinib dosing regimen

PURPOSE

An attenuated dosing (AD) sunitinib regimen of 37.5 mg daily has been suggested to reduce the toxicity reported with the standard dosing regimen to metastatic renal cell carcinoma (mRCC) patients. The aim of this study was to characterize the population pharmacokinetic (PK) properties of sunitinib and SU12662, the active metabolite, in patients receiving the AD regimen and to ascertain significant covariates influencing PK parameters.

METHODS

Thirty-one mRCC patients receiving AD sunitinib regimen were included. Plasma samples were collected on day 29 of each treatment cycle after the start of the therapy. Nonlinear mixed-effects modeling was applied to estimate the population PK properties of sunitinib and SU12662 as well as the effect of covariates on PK parameters. Monte Carlo simulation was also performed to predict the total trough level (TTL) of sunitinib and SU12662.

RESULTS

Sunitinib population means for CL/F and V d /F central were 13.8 L/h and 1720 L, respectively. SU12662 population means for CL/F and V d /F were 42.1 L/h and 1410 L, respectively. Body surface area (BSA) and ABCB1 polymorphism significantly influenced the CL/F variability of sunitinib: CL/F parent = 13.8 × exp((BSA - 1.75) × 2.08 + (ABCB1 genotype - 0.67) × 0.61), ABCB1-0: wild genotype, 1: mutant genotype. The effect size of ABCB1 mutant genotype and BSA greater than 1.75 m(2) in relation to sunitinib clearance was 31.14 % (p = 0.006) and 22.11 % (p = 0.011), respectively, relative to the reference group.

CONCLUSIONS

Adjusting doses of sunitinib according to BSA and ABCB1 polymorphism in Asian mRCC patients may be recommended for sufficient attainment of a target TTL of sunitinib and its metabolite.

Tumor suppressor miR-149-5p is associated with cellular migration, proliferation and apoptosis in renal cell carcinoma

Several studies have recently explored the role of microRNAs (miRNAs, miRs) in the tumorigenesis of various types of cancer. miRNAs have been reported to be involved in numerous cell processes, including cell apoptosis, proliferation and migration, thus suggesting that miRNAs may have an important role in cancer progression. Downregulation of miR-149-5p has been detected in RCC tissues by microarray profiling; however, its expression and function in RCC has yet to be elucidated. In the present study, reverse transcription‑quantitative polymerase chain reaction was performed to detect the expression levels of miR‑149‑5p in RCC tissues and paired normal tissues. In order to determine whether miR-149-5p was able to regulate cell proliferation, apoptosis or migration, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, flow cytometric and wound healing assays were conducted. The results demonstrated that miR‑149‑5p was significantly downregulated in RCC tissues compared with in normal tissues (P<0.05). The restoration of miR-149-5p expression using synthetic mimics suppressed cell proliferation and migration, and promoted cell apoptosis. These results indicated that miR‑149‑5p may act as a tumor suppressor in RCC. The present study is the first, to the best of our knowledge, to identify miR‑149‑5p as a tumor suppressor in RCC. Future studies will be focused on the potential role of miR‑149‑5p as a biomarker for the early detection and prognostic prediction of RCC, and as a therapeutic target in RCC. In addition, further exploration regarding the pathways underlying the effects of miR‑149‑5p in RCC is required.

Association Study of a Functional Variant on ABCG2 Gene with Sunitinib-Induced Severe Adverse Drug Reaction

Sunitinib is a tyrosine kinase inhibitor and used as the first-line treatment for advanced renal cell carcinoma (RCC). Nevertheless, inter-individual variability of drug's toxicity was often observed among patients who received sunitinib treatment. This study is to investigate the association of a functional germline variant on ABCG2 that affects the pharmacokinetics of sunitinib with sunitinib-induced toxicity of RCC patients in the Japanese population. A total of 219 RCC patients were recruited to this pharmacogenetic study. ABCG2 421C>A (Q141K) was genotyped by using PCR-Invader assay. The associations of both clinical and genetic variables were evaluated with logistic regression analysis and subsequently receiver operating characteristic (ROC) curve was plotted. About 43% (92/216) of RCC patients that received sunitinib treatment developed severe grade 3 or grade 4 thrombocytopenia according to the National Cancer Institute-Common Terminology Criteria for Adverse Events version 3.0, the most common sunitinib-induced adverse reaction in this study. In the univariate analysis, both age (P = 7.77x10(-3), odds ratio (OR) = 1.04, 95%CI = 1.01-1.07) and ABCG2 421C>A (P = 1.87x10(-2), OR = 1.71, 95%CI = 1.09-2.68) showed association with sunitinib-induced severe thrombocytopenia. Multivariate analysis indicated that the variant ABCG2 421C>A is suggestively associated with severe thrombocytopenia (P = 8.41x10(-3), OR = 1.86, 95% CI = 1.17-2.94) after adjustment of age as a confounding factor. The area under curve (AUC) of the risk prediction model that utilized age and ABCG2 421C>A was 0.648 with sensitivity of 0.859 and specificity of 0.415. Severe thrombocytopenia is the most common adverse reaction of sunitinib treatment in Japanese RCC patients. ABCG2 421C>A could explain part of the inter-individual variability of sunitinib-induced severe thrombocytopenia.

Sunitinib therapy for metastatic renal cell carcinoma: A urologist’s perspective

Objective:

Sunitinib is seldom initiated and managed by urologists, and patients with metastatic renal cell carcinoma are often referred to geographically distant centres. We present the outcomes of patients on sunitinib therapy in a single-centre urological department. To the best of our knowledge, we provide one of the only urology-led services for these patients in the United Kingdom.

Method:

Between August 2009 and January 2013, an unselected group of patients with metastatic renal cell carcinoma receiving sunitinib therapy were analysed. Twenty-eight patients (20 males, eight females) with an average age of 64.8 years were included in our study.

Results:

Patients were seen on average 10.8 days following MDT and were given fortnightly appointments to monitor progress. There were 176 cycles of sunitinib delivered. A total of 39.3% patients required at least one dose reduction. The commonest adverse events were diarrhoea (71%), mucositis (46%) and hand-foot syndrome (36%). Partial response and stable disease were observed in 27.1% and 45.8% of patients, respectively. Progression-free survival (PFS) and overall survival (OS) were 8.6 months and 15.2 months, respectively. Compared to the literature, there were lower rates of haematological adverse events in our study; however, PFS and OS, response rates and dose reductions were comparable.

Conclusions:

This study highlights that such patients can be safely and effectively managed in a local hospital setting with a dedicated urological team, allowing for better continuity of care.

Efficacy and toxicity of sunitinib in metastatic renal cell carcinoma patients in Egypt

BACKGROUND

To evaluate our results in terms of response, survival and toxicity profile of sunitinib among Egyptian patients with metastatic renal cell carcinoma.

MATERIALS AND METHODS

Between January 2010 and December 2013, 44 patients with metastatic renal cell carcinoma who received sunitinib at an oncology center of Cairo university hospitals were enrolled in this retrospective analysis.

RESULTS

The median age of the patients was 53 years, 22 (50%) having localized disease at presentation ,while the remaining half of the patients presented with metastasis. At a median follow up of 19 months, 9 (21%) patients achieved partial remission, while disease was reported stable in 20 cases (45%) and progressive in 7 (16%), 4 (9%) being lost to follow up, and 4 (9%) had discontinued therapy due to toxicity. The median overall survival was 23 months (95%CI 15.2 - 30.9), while progression free survival was 12 months (95%CI 11.6 - 12.3). The most commonly reported non hematological grade 3 adverse events included mucositis (15.9%), hand-foot syndrome (13.6%), and fatigue (9%), while the predominant grade 3 or 4 laboratory abnormalities were neutropenia (6.8%), followed by anemia in 4.5% of patients.

CONCLUSIONS

Our efficacy data were comparable to the published literature in terms of progression free survival and overall survival , while toxicity profile is different from Asian and western countries. However, sunitinib adverse events were manageable and tolerable in most of our Egyptian patients.

Subgroup analysis of Japanese patients in a phase 3 study of lenvatinib in radioiodine-refractory differentiated thyroid cancer

Lenvatinib significantly prolonged progression-free survival (PFS) versus placebo in patients with radioiodine-refractory differentiated thyroid cancer (RR-DTC) in the phase 3 Study of (E7080) Lenvatinib in Differentiated Cancer of the Thyroid (SELECT) trial. This subanalysis evaluated the efficacy and safety of lenvatinib in Japanese patients who participated in SELECT. Outcomes for Japanese patients (lenvatinib, n = 30; placebo, n = 10) were assessed in relationship to the SELECT population (lenvatinib, n = 261; placebo, n = 131). The primary endpoint was PFS; secondary endpoints included overall survival, overall response rate, and safety. Lenvatinib PFS benefit was shown in Japanese patients (median PFS: lenvatinib, 16.5 months; placebo, 3.7 months), although significance was not reached, presumably due to sample size (hazard ratio, 0.39; 95% confidence interval, 0.10-1.57; P = 0.067). Overall response rates were 63.3% and 0% for lenvatinib and placebo, respectively. No significant difference was found in overall survival. The lenvatinib safety profile was similar between the Japanese and overall SELECT population, except for higher incidences of hypertension (any grade: Japanese, 87%; overall, 68%; grade ≥3: Japanese, 80%; overall, 42%), palmar-plantar erythrodysesthesia syndrome (any grade: Japanese, 70%; overall, 32%; grade ≥3: Japanese, 3%; overall, 3%), and proteinuria (any grade: Japanese, 63%; overall, 31%; grade ≥3: Japanese, 20%; overall, 10%). Japanese patients had more dose reductions (Japanese, 90%; overall, 67.8%), but fewer discontinuations due to adverse events (Japanese, 3.3%; overall, 14.2%). There was no difference in lenvatinib exposure between the Japanese and overall SELECT populations after adjusting for body weight. In Japanese patients with radioiodine-refractory differentiated thyroid cancer, lenvatinib showed similar clinical outcomes to the overall SELECT population. Some differences in adverse event frequencies and dose modifications were observed. Clinical trial registration no.: NCT01321554.

RandomizEd phase II trial of Sunitinib four weeks on and two weeks off versus Two weeks on and One week off in metastatic clear-cell type REnal cell carcinoma: RESTORE trial

BACKGROUND

The standard sunitinib schedule, 4 weeks on, followed by 2 weeks off (4/2 schedule), is associated with troublesome toxicities, and maintenance of adequate sunitinib dosing and drug levels, which are essential for achieving an optimal treatment outcome, is challenging. The objective of this study was to investigate the efficacy and safety of an alternative sunitinib dosing schedule of 2 weeks on and 1 week off (2/1 schedule) compared with the standard sunitinib schedule of 4 weeks on and 2 weeks off (4/2 schedule).

PATIENTS AND METHODS

In this multicenter, randomized, open-label, phase II trial, treatment-naïve patients with clear-cell type metastatic renal cell carcinoma (mRCC) were randomly assigned to 4/2 or 2/1 schedules after stratification by Memorial Sloan Kettering Cancer Center risk group and the presence or absence of measurable lesions. The primary end point was the 6-month failure-free survival (FFS) rate, determined by intention-to-treat analysis.

RESULTS

From November 2007 to February 2014, 76 patients were accrued, and 74 were eligible. FFS rates at 6 months were 44% with the 4/2 schedule (N = 36) and 63% with the 2/1 schedule (N = 38). Neutropenia (all grades, 61% versus 37%; grade 3-4, 28% versus 11%) and fatigue (all grades, 83% versus 58%) were more frequently observed with schedule 4/2. There was a strong tendency toward a lower incidence of stomatitis, hand-foot syndrome, and rash with schedule 2/1. Objective response rates (ORRs) were 47% in schedule 2/1 and 36% in schedule 4/2. With a median follow-up of 30.0 months, the median time to progression (TTP) was 12.1 months in schedule 2/1 and 10.1 months in schedule 4/2.

CONCLUSION

Sunitinib administered with a 2/1 schedule is associated with less toxicity and higher FFS at 6 months than a 4/2 schedule, without compromising the efficacy in terms of ORR and TTP (NCT00570882).

Induction of apoptotic cell death by betulin in multidrug-resistant human renal carcinoma cells

Betulin, a triterpene from the bark of various species of birch tree, has various biological effects, including antiviral, antifungal and anticancer activities. The aim of the present study was to elucidate the mechanisms underlying the apoptotic effect of betulin in RCC4 multidrug-resistant human renal carcinoma cells. To evaluate anticancer activity, we performed cell viability and caspase activity assays, a proteome profiler array and western blot analysis in RCC4 cells. Betulin significantly decreased RCC4 cell viability in a time- and concentration-dependent manner. Betulin activated caspase family proteins, including caspase-3, -7, -8 and -9, and increased the expression of apoptosis-related proteins, including PARP and Bcl-2 family members. In an apoptosis array, betulin activated the tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) receptors TRAIL R1/DR4 and R2/DR5, and tumour necrosis factor receptor 1 (TNFR1), suggesting that betulin treatment leads to induction of apoptosis through both intrinsic and extrinsic apoptosis pathways in RCC4 cells. Notably, betulin significantly enhanced cytotoxicity and PARP cleavage in etoposide-treated RCC4 cells, and downregulated the expression of multidrug resistance protein 1 (MDR1). Taken together, our findings suggest that the anticancer effects of betulin involve induction of apoptosis and sensitisation of RCC4 cells, providing potentially useful information applicable to the use of betulin in renal cancer treatment.

Management of dose variability and side effects for individualized cancer pharmacotherapy with tyrosine kinase inhibitors

Molecular-targeted therapies with tyrosine kinase inhibitors (TKIs) have provided a major breakthrough in cancer treatment. These agents are given orally and demonstrated to be substrates for drug transporters. In clinical settings, TKIs are mainly used at a fixed dose, but wide interpatient variability has been observed in their pharmacokinetics and/or pharmacodynamics. Genetic polymorphisms of ABC transporters, drug-drug interaction and adherence are among the factors causing such variation. To overcome these problems, therapeutic drug monitoring has been applied in clinical practice for patient care. Skin disorders are frequently observed as adverse drug reactions when using TKIs, and are commonly managed by symptomatic therapy based on clinical experience. Recent studies have provided some insights into the molecular mechanisms underlying skin disorders induced by TKIs. This review article summarizes the accumulated clinical and basic pharmacological evidence of TKIs, focusing on erlotinib, sorafenib and sunitinib.

Axitinib plasma pharmacokinetics and ethnic differences

Axitinib, a potent and selective tyrosine kinase inhibitor of vascular endothelial growth factor receptors 1, 2, and 3, showed improved progression-free survival over sorafenib in patients previously treated for advanced renal cell carcinoma in the AXIS trial. Although a few studies had established the efficacy and safety of axitinib in Asian patients, additional evaluation was necessary to obtain regulatory approval in several Asian countries, especially in light of ethnic differences that are known to exist in genetic polymorphisms for metabolizing enzymes such as cytochrome P450 (CYP) 3A5, CYP2C19 and uridine diphosphate glucuronosyltransferase (UGT) 1A1, which are involved in axitinib metabolism. Axitinib plasma pharmacokinetics following single or multiple administration of oral axitinib in Asian (Japanese or Chinese) healthy subjects as well as Asian patients with advanced solid tumors was compared with that obtained in Caucasians. Upon review, the data demonstrated that axitinib can be characterized as not sensitive to ethnic factors based on its pharmacokinetic and pharmacodynamic properties. Axitinib exhibited similar pharmacokinetics in Asian and non-Asian subjects. A pooled population pharmacokinetic analysis indicated lack of a clinically meaningful effect of ethnicity on axitinib disposition. Therefore, dose adjustment for axitinib on the basis of ethnicity is not currently warranted.

The effect of ABCG2 genotype on the population pharmacokinetics of sunitinib in patients with renal cell carcinoma

BACKGROUND

Sunitinib, a multitargeted tyrosine kinase inhibitor, offers favorable therapeutic outcomes to patients with advanced renal cell carcinoma. However, to maximize the clinical benefits, an effective therapeutic management strategy with dose optimization is essential. The objectives of this analysis were to describe the pharmacokinetics (PK) of sunitinib by a population PK approach and to quantitatively evaluate the effect of potential predictive factors including ABCG2 genotype on the PK of sunitinib.

METHODS

Plasma concentration-time profiles at 3 consecutive days including a total of 245 sunitinib plasma concentrations were available from 19 Japanese patients with renal cell carcinoma. Blood samples were collected on days 2, 8, and 15 after the start of the therapy. Population PK analysis was performed using NONMEM 7.2. Body weight, gender, and genotype of ABCG2 421C>A were evaluated as potential covariates. Interoccasion variability (IOV) among the 3 sampling days was also assessed as a random effect parameter.

RESULTS

The sunitinib PK profiles were best described by a 1-compartment model with first-order absorption. The ABCG2 421C>A genotype was identified as a significant covariate for the prediction of oral clearance (CL/F). No significant improvement in model fit was observed by including body weight and/or gender. A systematic difference in estimated population CL/F was observed between days 2 and 8, which was quantified as approximately 30% decrease over time. This difference was described as a covariate for CL/F in the model. IOV included as a random effect parameter significantly improved the model fit.

CONCLUSIONS

This analysis provides a population PK model of sunitinib with the ABCG2 421C>A genotype as a predictive covariate for CL/F. It also suggests that IOV and change of CL/F over time need to be considered to predict the sunitinib PK more accurately. These findings will be implemented to optimize the pharmacotherapy of sunitinib.

Central and Eastern European experience with sunitinib in metastatic renal cell carcinoma: a sub-analysis of the global expanded-access trial

A global, open-label, expanded-access trial (EAT) provided sunitinib treatment on a compassionate-use basis to patients with metastatic renal cell carcinoma (mRCC) between 2005 and 2011. This retrospective analysis examines outcomes in patients from Central and East European (CEE) countries participating in the global EAT. Sunitinib (starting dose 50 mg orally once daily, with dose reduction for toxicity) was administered in repeated 6-week cycles (4 weeks on and 2 weeks off) until occurrence of disease progression or unacceptable toxicity. Tumor assessments were guided by Response Evaluation Criteria in Solid Tumors (RECIST) criteria but were performed according to local standards of care. In total, 401 CEE patients received sunitinib (median treatment duration 9.6 months), of whom 378 were evaluable for tumor response. The most frequent grade ≥3 toxicities were fatigue (7.5 %), hypertension (7.0 %), thrombocytopenia (6.5 %), diarrhea (4.2 %), nausea and hand-foot syndrome (both 3.7 %) and neutropenia (3.0 %). Median overall survival was 30.7 months (95 % CI 23.3, ‒ months). Overall survival tended to be longer in cytokine-naïve than cytokine-experienced patients (median 60.8 vs. 27.5 months; P = 0.1324). Among patients with evaluable tumors, 4.0 % achieved a complete and 14.6 % a partial response [objective response rate (ORR) 18.5 % (95 % CI 14.7, 22.8 %)]. Median progression-free survival was 11.6 months (95 % CI 10.3, 12.8 months). Sunitinib demonstrates safety and effectiveness in real-world mRCC patients in CEE countries. Expanded-access program patients showed a lower tumor response rate but similar survival outcomes to patients in the pivotal Phase III clinical trial of sunitinib in mRCC.

Impact of adverse events, treatment modifications, and dose intensity on survival among patients with advanced renal cell carcinoma treated with first-line sunitinib: a medical chart review across ten centers in five European countries

Angiogenesis inhibitors have become standard of care for advanced and/or metastatic renal cell carcinoma (RCC), but data on the impact of adverse events (AEs) and treatment modifications associated with these agents are limited. Medical records were abstracted at 10 tertiary oncology centers in Europe for 291 patients ≥18 years old treated with sunitinib as first-line treatment for advanced RCC (no prior systemic treatment for advanced disease). Logistic regression models were estimated to compare dose intensity among patients who did and did not experience AEs during the landmark periods (18, 24, and 30 weeks). Cox proportional hazard models were used to explore the possible relationship of low-dose intensity (defined using thresholds of 0.7, 0.8, and 0.9) and treatment modifications during the landmark periods to survival. 64.4% to 67.9% of patients treated with sunitinib reported at least one AE of any grade, and approximately 10% of patients experienced at least one severe (grade 3 or 4) AE. Patients reporting severe AEs were statistically significantly more likely to have dose intensities below either 0.8 or 0.9. Dose intensity below 0.7 and dose discontinuation during all landmark periods were statistically significantly associated with shorter survival time. This study of advanced RCC patients treated with sunitinib in Europe found a significant relationship between AEs and dose intensity. It also found correlations between dose intensity and shorter survival, and between dose discontinuation and shorter survival. These results confirm the importance of tolerable treatment and maintaining dose intensity.

Clinical response to sunitinib as a multitargeted tyrosine-kinase inhibitor (TKI) in solid cancers: a review of clinical trials

Angiogenesis is an integral process in carcinogenesis, and molecular inhibitors of angiogenic factors are currently being tested as treatments for cancer. Sunitinib is an oral multitargeted tyrosine-kinase inhibitor that blocks activation through the stem cell-factor receptor (Kit) and platelet-derived growth-factor receptor. Sunitinib has shown potent antitumor activity against several solid tumors, including renal cell carcinoma, gastrointestinal stromal tumors, and neuroendocrine tumors in several Phase II/III trials. Recently, sunitinib has been used to treat other solid cancers, such as lung cancer, pancreatic cancer, chondrosarcoma, esophageal cancer, bladder cancer, glioma, and aggressive fibromatosis, and also showed potential efficacy in progression-free survival and overall survival. In this review, we examine the efficacy of sunitinib as a molecular-targeted therapy in patients with different types of solid cancers.

Anti-VEGF therapy in mRCC: differences between Asian and non-Asian patients

Background:

Several reports suggest that vascular endothelial growth factor (VEGF)-targeted therapy in metastatic renal cell carcinoma (mRCC) may be more toxic in Asian vs non-Asian populations. Comparative efficacy of these agents with respect to ethnicity is not well characterised.

Methods:

A multicentre, retrospective, cohort study using Asian and non-Asian centres which collected data on ethnicity, dose reductions and outcomes using the International mRCC Database Consortium.

Results:

This study included 1024 (464 Asian, 560 non-Asian) patients with a 29.4 months median follow-up. The percentage of dose modifications/reductions between non-Asians and Asians was similar (55% vs 61% P=0.1197). When adjusted for risk groups, there was no difference in overall or progression-free survival between non-Asians and Asians. Patients with dose reductions due to toxicity had longer treatment durations and overall survival than those who did not in both non-Asian (10.6 vs 5.0 months, P<0.0001; 22.6 vs 16.1 months, P=0.0016, respectively) and Asian populations (8.9 vs 5.4 months, P=0.0028; 28.0 vs 18.7 months, P=0.0069, respectively).

Conclusions:

Adjusting for risk groups, there appears to be no difference in outcome between Asian vs non-Asian patients with mRCC treated with VEGF-targeted therapy. Judicious dose reductions may allow for better outcomes in both populations due to longer treatment durations, but direct comparisons are needed.

Intolerance to sunitinib treatment in hemodialysis patients with metastatic renal cell carcinoma

Sunitinib is a multiple tyrosine kinase receptor inhibitor that is approved for the treatment of metastatic renal cell carcinoma (RCC). However, neither an appropriate dose nor dosing schedule of sunitinib has yet been established for patients with metastatic RCC who are on hemodialysis. Here, we report on two hemodialysis patients who received sunitinib to treat metastatic RCC. Sunitinib was planned to be administered at a dosage of 25 mg/d for 4 of every 6 weeks. Although sunitinib toxicity was manageable in one patient, disease progression occurred after 4 months of treatment. In the second patient, acute pulmonary edema, caused by uncontrolled hypertension, developed on the 15th day of sunitinib therapy and the drug had to be discontinued. Sunitinib is thus not well tolerated in a hemodialysis setting. Close monitoring of toxicity and dose manipulation may be required if such therapy is attempted.

Angiogenesis inhibitor therapies for advanced renal cell carcinoma: toxicity and treatment patterns in clinical practice from a global medical chart review

The aim of this study was to assess the treatment patterns and safety of sunitinib, sorafenib and bevacizumab in real-world clinical settings in US, Europe and Asia. Medical records were abstracted at 18 community oncology clinics in the US and at 21 tertiary oncology centers in US, Europe and Asia for 883 patients ≥18 years who had histologically/cytologically confirmed diagnosis of advanced RCC and received sunitinib (n=631), sorafenib (n=207) or bevacizumab (n=45) as first-line treatment. No prior treatment was permitted. Data were collected on all adverse events (AEs) and treatment modifications, including discontinuation, interruption and dose reduction. Treatment duration was estimated using Kaplan-Meier analysis. Demographics were similar across treatment groups and regions. Median treatment duration ranged from 6.1 to 10.7 months, 5.1 to 8.5 months and 7.5 to 9.8 months for sunitinib, sorafenib and bevacizumab patients, respectively. Grade 3/4 AEs were experienced by 26.0, 28.0 and 15.6% of sunitinib, sorafenib and bevacizumab patients, respectively. Treatment discontinuations occurred in 62.4 (Asia) to 63.1% (US) sunitinib, 68.8 (Asia) to 90.0% (Europe) sorafenib, and 66.7 (Asia) to 81.8% (US) bevacizumab patients. Globally, treatment modifications due to AEs occurred in 55.1, 54.2 and 50.0% sunitinib, sorafenib and bevacizumab patients, respectively. This study in a large, global cohort of advanced RCC patients found that angiogenesis inhibitors are associated with high rates of AEs and treatment modifications. Findings suggest an unmet need for more tolerable agents for RCC treatment.

Phase I study of the safety, pharmacokinetics and antitumor activity of famitinib

PURPOSE

To evaluate the safety, tolerability, pharmacokinetics and antitumor activities of famitinib (famitinib L-malate), a novel oral multitargeting tyrosine kinase inhibitor that acts against vascular endothelial growth factor receptor-2, platelet-derived growth factor receptor, stem cell factor receptor (c-kit), FMS-like tyrosine kinase-3 receptor and protooncogene tyrosine kinase receptor in patients with advanced solid cancer.

METHODS

Patients received once daily oral famitinib. Doses were increased from 4 to 8, 13, 20, 27, 24, 25 and eventually 30 mg. Each cycle was defined as 28 days. The pharmacokinetic profile and various biomarkers were evaluated during the first cycle. Antitumor efficacy was evaluated every 8 weeks.

RESULTS

Fifty-four patients were evaluable for safety and efficacy. Dose-limiting toxicities were observed in 2 of 3 patients at 30 mg. The dose-limiting toxicities observed in the first cycle of famitinib treatment included hypertension, hand-foot skin reaction and diarrhea. Grade 3 hypertriglyceridemia/hypercholesterolemia and proteinuria were notable side effects in the subsequent treatment cycles. Other common side effects included bone marrow suppression, oral mucositis, fatigue, pain, elevated transaminase or bilirubin, peripheral sensory disturbance and hypothyroidism, most of which were mild to moderate in severity. Pharmacokinetic studies revealed no significant accumulation of famitinib or its major metabolite, M3. The half-lives of famitinib and M3 were approximately 28.7-33.8 and 41.3-47.7 h, respectively. Food demonstrated a minimal effect on the pharmacokinetics of famitinib. Eight partial responses were determined, including 6 cases of renal cell carcinoma, 1 case of gastrointestinal stromal tumor (GIST) and 1 case of alveolar soft part sarcoma. Fourteen patients demonstrated stable disease with various degrees of tumor shrinkage.

CONCLUSIONS

Famitinib is generally well tolerated. Famitinib demonstrates a wide spectrum of antitumor activities, which warrants further study in renal cell carcinoma, GIST, hepatocellular carcinoma and soft tissue sarcoma. The recommended dose for future phase II clinical trials is 25 mg.

Effect of P-glycoprotein and breast cancer resistance protein inhibition on the pharmacokinetics of sunitinib in rats

The aim of this study was to elucidate the roles of P-glycoprotein (P-gp/ABCB1) and breast cancer resistance protein (BCRP/ABCG2) in the plasma concentration, biliary excretion, and distribution to the liver, kidney, and brain of sunitinib. The pharmacokinetics of sunitinib was examined in rats treated with PSC833 (valspodar) and pantoprazole, potent inhibitors of P-gp and BCRP, respectively. The sunitinib concentrations in plasma, bile, liver, kidney, and brain were determined by liquid chromatography-tandem mass spectrometry. It was found that the area under the concentration-time curve for 4 hours (AUC0-4) and maximum concentration (Cmax) of sunitinib administered intraintestinally were significantly increased by pretreatment with PSC833 or pantoprazole. Each inhibitor markedly reduced the biliary excretion of sunitinib for 60 minutes after an intravenous administration and significantly increased the distribution of sunitinib to the liver as well as kidney. In addition, the brain distribution of sunitinib was significantly increased by PSC833 but not pantoprazole, and coadministration of both inhibitors further enhanced the accumulation of sunitinib in the brain. These results demonstrate that plasma concentrations of sunitinib and the biliary excretion and distribution to the kidney, liver, and brain of sunitinib are influenced by pharmacologic inhibition of P-gp and/or BCRP.

Prognostic factors for survival in 1059 patients treated with sunitinib for metastatic renal cell carcinoma

BACKGROUND

Prognostic factors for progression-free survival (PFS), overall survival (OS), and long-term OS (≥30 months) were investigated in sunitinib-treated patients with metastatic renal cell carcinoma (RCC).

METHODS

Data were pooled from 1059 patients in six trials. Baseline variables, including ethnicity, were analysed for prognostic significance by Cox proportional-hazards model.

RESULTS

Median PFS and OS were 9.7 and 23.4 months, respectively. Multivariate analysis of PFS and OS identified independent predictors, including ethnic origin, Eastern Cooperative Oncology Group performance status, time from diagnosis to treatment, prior cytokine use, haemoglobin, lactate dehydrogenase, corrected calcium, neutrophils, platelets, and bone metastases (OS only). Characteristics of long-term survivors (n=215, 20%) differed from those of non-long-term survivors; independent predictors of long-term OS included ethnic origin, bone metastases, and corrected calcium. There were no differences in PFS (10.5 vs 7.2 months; P=0.1006) or OS (23.8 vs 21.4 months; P=0.2135) in white vs Asian patients; however, there were significant differences in PFS (10.5 vs 5.7 months; P<0.001) and OS (23.8 vs 17.4 months; P=0.0319) in white vs non-white, non-Asian patients.

CONCLUSION

These analyses identified risk factors to survival with sunitinib, including potential ethnic-based differences, and validated risk factors previously reported in advanced RCC.

Pharmacokinetic/Pharmacodynamic Analysis of a Hemodialyzed Patient Treated with 25 mg of Sunitinib

Sunitinib has been approved for the treatment of advanced and/or metastatic renal cell carcinoma (RCC). Information on the dosage adjustment of sunitinib for patients undergoing hemodialysis is limited. Especially, efficacy and tolerance of sunitinib at a low dose in such patients are not fully understood. Thus, we examined the effect of hemodialysis on the pharmacokinetics, safety and efficacy of 25 mg of sunitinib. The patient was a 66-year-old man diagnosed with RCC and undergoing hemodialysis. He was treated with sunitinib at 25 mg daily for 4 weeks of a 6-week cycle. There were little differences in the AUC_{0–24 h} of sunitinib and its major active metabolite SU12662 on day 17 (on hemodialysis) and day 18 (off hemodialysis) of the first cycle. The total sunitinib concentration (sunitinib and SU12662) was approximately 50 ng/ml at a steady state in every cycle. The patient's genotype was wild type for ABCG2 421C>A, which is associated with increased sunitinib exposure. In the following two cycles of sunitinib, computed tomography scan showed a partial response of the lung metastasis. During the first cycle, the patient developed grade 2 thrombocytopenia and leukocytopenia. After four cycles of treatment, the patient developed grade 3 fatigue and the sunitinib treatment was discontinued. Our patient on hemodialysis could be safely and effectively treated with 25 mg of sunitinib, and a total sunitinib concentration of about 50 ng/ml was maintained. The pharmacokinetics of sunitinib and SU12662 were rarely affected by hemodialysis. Therapeutic drug monitoring could be helpful during sunitinib therapy, especially in a specific population.

Impact of genetic variation in breast cancer resistance protein (BCRP/ABCG2) on sunitinib pharmacokinetics

To elucidate the impact of genetic variations in breast cancer resistance protein (BCRP/ABCG2) and P-glycoprotein (MDR1/ABCB1) on the pharmacokinetics of sunitinib, we carried out a pharmacogenetic study in a clinical setting and pharmacokinetic analysis using Abcg2(-/-), Abcb1a/1b(-/-) and Abcb1a/1b;Abcg2(-/-) mice. Nineteen renal cell carcinoma patients were enrolled in this study. The plasma concentrations of sunitinib and its active metabolite were determined and the area under the concentration-time curve (AUC) was calculated. Genetic polymorphisms in ABCG2 (421C>A) and ABCB1 (1236C>T, 2677G>T/A and 3435C>T) were examined. The dose-adjusted AUC(0-24) of sunitinib was significantly higher in patients with a heterozygous variant for ABCG2 421C>A than in wild-type patients (p = 0.02), and one homozygous patient showed the highest dose-adjusted AUC(0-24). The ABCB1 polymorphisms were not associated with the dose-adjusted AUC(0-24). The maximum concentration and AUC(0-4) of sunitinib were significantly higher in Abcg2(-/-), Abcb1a/1b(-/-) and Abcb1a/1b;Abcg2(-/-) mice than wild-type mice when sunitinib was given orally but not intraperitoneally. Incidence of thrombocytopenia and hypertension and poor compliance were associated with the systemic exposure to sunitinib and its active metabolite. These results suggest that the loss of protein expression of ABCG2 by genetic polymorphism is associated with an increase in the systemic exposure to sunitinib and sunitinib-induced toxicity.

Therapy management with sunitinib in patients with metastatic renal cell carcinoma: key concepts and the impact of clinical biomarkers

Targeted agents have improved prognosis for patients with metastatic renal cell carcinoma (mRCC), and they are changing therapeutic expectations with respect to long-term clinical outcomes for these patients. However, in order to obtain the maximum clinical benefit from targeted agents, effective therapy management is essential and includes optimization of dosing and treatment duration, as well as adequate side-effect management. Sunitinib has demonstrated efficacy for the treatment of patients with mRCC and is a reference standard of care for first-line therapy. However, in clinical practice, it is difficult to determine the best treatment strategy with targeted agents due to long-term tolerability and the development of resistance. An individualized therapeutic strategy in RCC requires a comprehensive understanding of the biology of response and resistance to targeted therapy. Here we review the clinical data regarding the efficacy and safety for sunitinib and highlight the importance of therapy management, as well as the potential use of clinical biomarkers in order to maximize the clinical benefit from sunitinib treatment in patients with mRCC.

Current status of targeted therapy for advanced renal cell carcinoma

The treatment of metastatic renal cell carcinoma (mRCC) has recently evolved from being predominantly cytokine-based treatment to the use of targeted agents, which include sorafenib, sunitinib, bevacizumab (plus interferon alpha [IFN-α]), temsirolimus, everolimus, pazopanib, and most recently, axitinib. Improved understanding of the molecular pathways implicated in the pathogenesis of RCC has led to the development of specific targeted therapies for treating the disease. In Korea, it has been 5 years since targeted therapy became available for mRCC. Thus, we now have broader and better therapeutic options at hand, leading to a significantly improved prognosis for patients with mRCC. However, the treatment of mRCC remains a challenge and a major health problem. Many questions remain on the efficacy of combination treatments and on the best methods for achieving complete remission. Additional studies are needed to optimize the use of these agents by identifying those patients who would most benefit and by elucidating the best means of delivering these agents, either in combination or as sequential single agents. Furthermore, numerous ongoing research activities aim at improving the benefits of the new compounds in the metastatic situation or their application in the early phase of the disease. This review introduces what is currently known regarding the fundamental biology that underlies clear cell RCC, summarizes the clinical evidence supporting the benefits of targeted agents in mRCC treatment, discusses survival endpoints used in pivotal clinical trials, and outlines future research directions.