Sunitinib in Metastatic Renal Cell Carcinoma: The Pharmacological Basis of the Alternative 2/1 Schedule

Utility of the food colorant erythrosine B as an effective green probe for quantitation of the anticancer sunitinib. Application to pharmaceutical formulations and human plasma

Sunitinib is a tyrosine kinase inhibitor used for the treatment of renal cell carcinoma and gastrointestinal stromal tumors. In this study, two spectroscopic methods, spectrofluorometric and spectrophotometric, were utilized to quantify sunitinib in different matrices. In method I, the native fluorescence of erythrosine B was quenched by forming ion-pair complex with increasing quantities of sunitinib. This approach was utilized for measuring sunitinib in its dosage forms and spiked plasma. After excitation at 528 nm, the quenching of fluorescence is linearly related to the concentration across the range of 0.05-0.5 μg mL-1 at 550 nm in Britton-Robinson buffer (pH 4.0), with a correlation value of 0.9999 and a high level of sensitivity with detection limit down to 10 ng mL-1 . Method II relies on spectrophotometric measurements of the produced complex at 550 nm across a range of 0.5-10.0 μg mL-1 , with good correlation value of 0.9999. This method has a detection limit down to 0.16 μg mL-1 . The proposed methodologies were validated according to International Conference on Harmonization (ICH) guidelines with satisfactory results. The stoichiometry of the reaction was determined through the application of Job's method, while the mechanism of quenching was investigated by employing the Stern-Volmer plot. The designated methods were used to estimate sunitinib in its capsules and in spiked human plasma. Additionally, the statistical analysis of the data revealed no substantial differences when compared to previous reported spectroscopic method. Green assessment tools provide further details about the eco-friendly nature of the methods.

A comprehensive regulatory and industry review of modeling and simulation practices in oncology clinical drug development

Exposure-response (E-R) analyses are an integral component in the development of oncology products. Characterizing the relationship between drug exposure metrics and response allows the sponsor to use modeling and simulation to address both internal and external drug development questions (e.g., optimal dose, frequency of administration, dose adjustments for special populations). This white paper is the output of an industry-government collaboration among scientists with broad experience in E-R modeling as part of regulatory submissions. The goal of this white paper is to provide guidance on what the preferred methods for E-R analysis in oncology clinical drug development are and what metrics of exposure should be considered.

[Acute Acalculous Cholecystitis Associated with Sunitinib Treatment for Renal Cell Carcinoma]

A 64-year-old man was treated with sunitinib as a first-line therapy for metastatic renal cell carcinoma. He was given oral sunitinib in cycles of 50 mg once daily for 2 weeks followed by a week off. During the 5th week of treatment right upper quadrant pain developed, but this resolved spontaneously during the 6th week (off treatment). However, on the 8th week of treatment, he was admitted to hospital because the acute right upper quadrant pain recurred with nausea, vomiting, and fever. Acute acalculous cholecystitis was then diagnosed by ultrasonography and CT. In addition, his laboratory findings indicated disseminated intravascular coagulation. Accordingly, sunitinib therapy was discontinued and broad-spectrum antibiotics initiated. He subsequently recovered after emergent percutaneous cholecystostomy. His Naranjo Adverse Drug Reaction Probability Scale score was 7, indicaing a probable association of the event with sunitinib. Suspicion of sunitinib-related acute cholecystitis is required, because, although uncommon, it can be life-threatening.

Significance of introduction of alternative dosing schedule for sunitinib during first-line treatment of patients with metastatic renal cell carcinoma

The objective of this study was to investigate the significance of an alternative dosing schedule for sunitinib in metastatic renal cell carcinoma (mRCC) patients. This study included 154 patients treated with sunitinib as first-line systemic therapy for mRCC, consisting of 62, 47, and 45 receiving sunitinib based on a traditional schedule (TS, 4 weeks on and 2 weeks off) alone (TS group), alternative schedule (AS, 2 weeks on and 1 week off) alone (AS group), and TS followed by AS after the development of dose-limiting toxicities (TS-to-AS group), respectively. There were no significant differences in the major clinicopathological characteristics among these three groups. The progression-free survival in the TS group was significantly shorter than in the other two groups, while no significant differences in the overall survival were noted among the three groups. Adverse events (AEs) ≥ grade 3 in the TS and TS-to-AS groups occurred more frequently than in the AS group. Furthermore, there were significant differences in the incidences of AEs, including diarrhea, fatigue, and hypertension, among the three groups, favoring the AS compared with the other two groups. Despite the lack of a significant difference in the incidence of dose reduction among the three groups, the incidences of the interruption and discontinuation of sunitinib in the AS group were significantly lower than in the other two groups. These findings suggest that the introduction of AS for sunitinib during first-line treatment for mRCC patients may promote favorable clinical outcomes regarding the prognosis as well as tolerability compared with treatment on TS alone.