The Alternative 2/1 Schedule of Sunitinib is Superior to the Traditional 4/2 Schedule in Patients With Metastatic Renal Cell Carcinoma: A Meta-analysis

Temporary treatment cessation versus continuation of first-line tyrosine kinase inhibitor in patients with advanced clear cell renal cell carcinoma (STAR): an open-label, non-inferiority, randomised, controlled, phase 2/3 trial

BACKGROUND

Temporary drug treatment cessation might alleviate toxicity without substantially compromising efficacy in patients with cancer. We aimed to determine if a tyrosine kinase inhibitor drug-free interval strategy was non-inferior to a conventional continuation strategy for first-line treatment of advanced clear cell renal cell carcinoma.

METHODS

This open-label, non-inferiority, randomised, controlled, phase 2/3 trial was done at 60 hospital sites in the UK. Eligible patients (aged ≥18 years) had histologically confirmed clear cell renal cell carcinoma, inoperable loco-regional or metastatic disease, no previous systemic therapy for advanced disease, uni-dimensionally assessed Response Evaluation Criteria in Solid Tumours-defined measurable disease, and an Eastern Cooperative Oncology Group performance status of 0-1. Patients were randomly assigned (1:1) at baseline to a conventional continuation strategy or drug-free interval strategy using a central computer-generated minimisation programme incorporating a random element. Stratification factors were Memorial Sloan Kettering Cancer Center prognostic group risk factor, sex, trial site, age, disease status, tyrosine kinase inhibitor, and previous nephrectomy. All patients received standard dosing schedules of oral sunitinib (50 mg per day) or oral pazopanib (800 mg per day) for 24 weeks before moving into their randomly allocated group. Patients allocated to the drug-free interval strategy group then had a treatment break until disease progression, when treatment was re-instated. Patients in the conventional continuation strategy group continued treatment. Patients, treating clinicians, and the study team were aware of treatment allocation. The co-primary endpoints were overall survival and quality-adjusted life-years (QALYs); non-inferiority was shown if the lower limit of the two-sided 95% CI for the overall survival hazard ratio (HR) was 0·812 or higher and if the lower limit of the two-sided 95% CI of the marginal difference in mean QALYs was -0·156 or higher. The co-primary endpoints were assessed in the intention-to-treat (ITT) population, which included all randomly assigned patients, and the per-protocol population, which excluded patients in the ITT population with major protocol violations and who did not begin their randomisation allocation as per the protocol. Non-inferiority was to be concluded if it was met for both endpoints in both analysis populations. Safety was assessed in all participants who received a tyrosine kinase inhibitor. The trial was registered with ISRCTN, 06473203, and EudraCT, 2011-001098-16.

FINDINGS

Between Jan 13, 2012, and Sept 12, 2017, 2197 patients were screened for eligibility, of whom 920 were randomly assigned to the conventional continuation strategy (n=461) or the drug-free interval strategy (n=459; 668 [73%] male and 251 [27%] female; 885 [96%] White and 23 [3%] non-White). The median follow-up time was 58 months (IQR 46-73 months) in the ITT population and 58 months (46-72) in the per-protocol population. 488 patients continued on the trial after week 24. For overall survival, non-inferiority was demonstrated in the ITT population only (adjusted HR 0·97 [95% CI 0·83 to 1·12] in the ITT population; 0·94 [0·80 to 1·09] in the per-protocol population). Non-inferiority was demonstrated for QALYs in the ITT population (n=919) and per-protocol (n=871) population (marginal effect difference 0·06 [95% CI -0·11 to 0·23] for the ITT population; 0·04 [-0·14 to 0·21] for the per-protocol population). The most common grade 3 or worse adverse events were hypertension (124 [26%] of 485 patients in the conventional continuation strategy group vs 127 [29%] of 431 patients in the drug-free interval strategy group); hepatotoxicity (55 [11%] vs 48 [11%]); and fatigue (39 [8%] vs 63 [15%]). 192 (21%) of 920 participants had a serious adverse reaction. 12 treatment-related deaths were reported (three patients in the conventional continuation strategy group; nine patients in the drug-free interval strategy group) due to vascular (n=3), cardiac (n=3), hepatobiliary (n=3), gastrointestinal (n=1), or nervous system (n=1) disorders, and from infections and infestations (n=1).

INTERPRETATION

Overall, non-inferiority between groups could not be concluded. However, there seemed to be no clinically meaningful reduction in life expectancy between the drug-free interval strategy and conventional continuation strategy groups and treatment breaks might be a feasible and cost-effective option with lifestyle benefits for patients during tyrosine kinase inhibitor therapy in patients with renal cell carcinoma.

FUNDING

UK National Institute for Health and Care Research.

Association of sunitinib concentration and clinical outcome in patients with metastatic renal cell carcinoma treated with a 2-week-on and 1-week-off schedule

WHAT IS KNOWN AND OBJECTIVE

Sunitinib is used as a first-line therapy for metastatic renal cell carcinoma. The primary aim of this study was to determine the optimal total sunitinib (sunitinib plus N-desethyl sunitinib) trough concentration for the alternative dosing schedule: 2-week-on and 1-week-off schedule (2/1 schedule).

METHODS

Patients with metastatic renal cell carcinoma treated with the 2/1 schedule of sunitinib, whose total sunitinib concentrations were available, were recruited for this study. Out of 19 patients, 17 whose sunitinib dosage was not changed until the measurement of drug concentration were eligible for the analysis of the relationship between total sunitinib concentration and clinical outcome. Individual pharmacokinetic parameters in 19 patients were estimated via the Bayesian analysis.

RESULTS

The onset of severe (grade ≥3) adverse effects among 17 patients during 3 weeks as a first course of sunitinib therapy was observed in 7 (41.2%) patients. The median total sunitinib concentration in patients with severe adverse effects was significantly higher compared with that in patients without severe adverse effects [median: 119 (113-131) vs. 87.8 (77.4-102) ng/mL, p = 0.01]. According to the receiver operating characteristic analysis of the onset of severe adverse effects, the cut-off value of the total sunitinib concentration was 108 ng/mL. Patients with a total sunitinib concentration lower than 108 ng/mL had a longer time to first dose reduction or withdrawal due to adverse effects compared with those with a total sunitinib concentration of 108 ng/mL or higher (p = 0.03). The probability without treatment failure was not significantly different between the two concentration groups. In addition, the estimated sunitinib apparent oral clearance (CL/F) was significantly lower in the severe adverse effects group. Our simulation demonstrated that 0.67-time dose is needed for patients with approximately 90.0 ng/mL of sunitinib concentration on day 7 to maintain the concentration at the same level as the patients with higher CL/F.

WHAT IS NEW AND CONCLUSION

Maintaining the total sunitinib trough concentrations of less than 108 ng/mL is safe to avoid the onset of serious adverse effects without increasing the treatment failure in patients with metastatic renal cell carcinoma treated with the 2/1 schedule of sunitinib.

Individualized Management of Blood Concentration in Patients with Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor, and surgical resection is the first choice for the treatment of the disease, but since the advent of tyrosine kinase inhibitors (TKIs) such as imatinib (IM), the prognosis of the disease has undergone revolutionary changes. According to the current version of the guidelines, most GIST patients receive a fixed dose without taking into account their own individual differences, resulting in a wide difference in blood concentration, adverse reactions and prognosis. With more studies on the relationship between blood drug concentrations and prognosis, the concept of individualized therapy has been paid more attention by researchers. Therapeutic drug monitoring (TDM) has also been made available for the research field of GIST targeted therapy. How to reduce the incidence of drug resistance and adverse reactions in patients with GISTs has become the focus of the current research. This article reviews the common monitoring methods and timing of TKIs blood concentration, the reasonable range of blood drug concentration, the toxic or adverse effects caused by high blood drug concentration, some possible factors affecting blood drug concentration and recent research progress, in order to discuss and summarize the treatment strategy of individual blood drug concentration, improve the prognosis of patients and reduce the adverse effects as much as possible.

Sunitinib malate inhibits intestinal tumor development in male ApcMin/+ mice by down-regulating inflammation-related factors with suppressing β-cateinin/c-Myc pathway and re-balancing Bcl-6 and Caspase-3

Sunitinib is a tyrosine kinase inhibitor for many tumors. Inflammation is one of the most important factors in the development of intestinal tumors. Many inflammation-related factors are regulated by tyrosine kinase receptors. It is reasonable to hypothesize that sunitinib can regulate the development of intestinal tumors by regulating the expression and/or activity of inflammation-related factors. Here, ApcMin/+ male mouse model was used to investigate the effect and mechanism of sunitinib malate against intestinal cancer. Results show that compared to vehicle, after sunitinib malate treatment, overall survival of ApcMin/+ mice was lengthened up to 25 days, with a gain of body weight, reduction of spleen/body weight index, and RBC, WBC and HGC regulated to normal levels of wild type mice, and a number of polyps no less than 1 mm significantly reduced. Meanwhile, in the intestines, the nuclear β-Catenin protein and c-Myc mRNA were both down-regulated, and Bcl-6 was significantly reduced with Caspase-3 up regulated. Furthermore, inflammation-related factors including IL-6, TNF-α, IL-1α, IL-1β and IFN-γ were down-regulated at mRNA levels in the intestines. These results suggest that sunitinib malate can significantly improve the survival status and inhibit intestinal tumor development in male ApcMin/+ mice, through inhibiting inflammation-related factors, while suppressing β-cateinin/c-Myc pathway and re-balancing protein levels of Bcl-6 and Caspase-3.

Targeting the Deterministic Evolutionary Trajectories of Clear Cell Renal Cell Carcinoma

The emergence of clinical resistance to currently available systemic therapies forces us to rethink our approach to clear cell renal cell carcinoma (ccRCC). The ability to influence ccRCC evolution by inhibiting processes that propel it or manipulating its course may be an adequate strategy. There are seven deterministic evolutionary trajectories of ccRCC, which correlate with clinical phenotypes. We suspect that each trajectory has its own unique weaknesses that could be exploited. In this review, we have summarized recent advances in the treatment of ccRCC and demonstrated how to improve systemic therapies from the evolutionary perspective. Since there are only a few evolutionary trajectories in ccRCC, it appears feasible to use them as potential biomarkers for guiding intervention and surveillance. We believe that the presented patient stratification could help predict future steps of malignant progression, thereby informing optimal and personalized clinical decisions.

Imatinib, sunitinib and pazopanib: From flat-fixed dosing towards a pharmacokinetically guided personalized dose

Tyrosine kinase inhibitors (TKIs) are anti‐cancer drugs that target tyrosine kinases, enzymes that are involved in multiple cellular processes. Currently, multiple oral TKIs have been introduced in the treatment of solid tumours, all administered in a fixed dose, although large interpatient pharmacokinetic (PK) variability is described. For imatinib, sunitinib and pazopanib exposure‐treatment outcome (efficacy and toxicity) relationships have been established and therapeutic windows have been defined, therefore dose optimization based on the measured blood concentration, called therapeutic drug monitoring (TDM), can be valuable in increasing efficacy and reducing the toxicity of these drugs.

In this review, an overview of the current knowledge on TDM guided individualized dosing of imatinib, sunitinib and pazopanib for the treatment of solid tumours is presented. We summarize preclinical and clinical data that have defined thresholds for efficacy and toxicity. Furthermore, PK models and factors that influence the PK of these drugs which partly explain the interpatient PK variability are summarized. Finally, pharmacological interventions that have been performed to optimize plasma concentrations are described. Based on current literature, we advise which methods should be used to optimize exposure to imatinib, sunitinib and pazopanib.

Does an Alternative Sunitinib Dosing Schedule Really Improve Survival Outcomes over a Conventional Dosing Schedule in Patients with Metastatic Renal Cell Carcinoma? An Updated Systematic Review and Meta-Analysis

Treatment-related adverse events (AEs) can obfuscate the maintenance of a conventional schedule of sunitinib in patients with metastatic renal cell carcinoma. Accordingly, alternative schedules seeking to improve the safety profile of sunitinib have been tested. Recently, two meta-analyses similarly described improved safety profiles favoring a two weeks on and one week off (2/1) schedule, but with conflicting results for survival outcomes. Therefore, we conducted an updated systematic review and meta-analysis, including all recently published studies and using complementary statistical methods. Endpoints included progression-free survival, overall survival, and AEs of 15 types. Eleven articles were included in this meta-analysis. Using adjusted findings, we noted statistically better results in progression-free survival (hazard ratio, 0.58; 95% confidence interval, 0.39–0.84; p = 0.005), but no difference in overall survival (hazard ratio, 0.66; 95% confidence interval, 0.42–1.04; p = 0.08). Moreover, the 2/1 schedule was beneficial for reducing the incidence of several AEs. Conclusively, our meta-analysis suggests that the 2/1 schedule holds promise as an alternative means of reducing AEs and maintaining patient quality of life. While the survival outcomes of the 2/1 schedule seem also to be favorable, the level of evidence for this was low, and the interpretation of these findings should warrant caution. Large scale randomized trials are needed to support these results.