Pharmacokinetics Of Sunitinib Research Articles

Effect of isavuconazole on the pharmacokinetics of sunitinib and its mechanism

BackgroundSunitinib, a newly developed multi-targeted tyrosine kinase inhibitor (TKI), has become a common therapeutic option for managing advanced renal cell carcinoma (RCC). Examining the mechanism underlying the interaction between sunitinib and isavuconazole was the aim of this effort.MethodsThe concentrations of sunitinib and its primary metabolite, N-desethyl sunitinib, were analyzed and quantified using ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Our study evaluated the potential interaction between isavuconazole and sunitinib using rat liver microsomes (RLM), human liver microsomes (HLM), and in vivo rat models. For the in vivo study, two groups (n = 5) of Sprague-Dawley (SD) rats were randomly allocated to receive sunitinib either with or without co-administration of isavuconazole. Additionally, the effects of isavuconazole on the metabolic stability of sunitinib and N-desethyl sunitinib were studied in RLM in vitro.ResultsOur findings demonstrated that in RLM, isavuconazole exhibited a mixed non-competitive and competitive inhibition mechanism, with an IC50 (half maximal inhibitory concentration) value of 1.33 µM. Meanwhile, in HLM, isavuconazole demonstrated a competitive inhibition mechanism, with an IC50 of 5.30 µM. In vivo studies showed that the presence of isavuconazole significantly increased the pharmacokinetic characteristics of sunitinib, with the AUC(0→t), AUC(0→∞), and Tmax rising to approximately 211.38%, 203.92%, and 288.89%, respectively, in contrast to the control group (5 mg/kg sunitinib alone). The pharmacokinetic characteristics of the metabolite N-desethyl sunitinib in the presence of isavuconazole remained largely unchanged compared to the control group. Furthermore, in vitro metabolic stability experiments revealed that isavuconazole inhibited the metabolic processing of both sunitinib and N-desethyl sunitinib.ConclusionsIsavuconazole had a major impact on sunitinib metabolism, providing fundamental information for the precise therapeutic administration of sunitinib.

Population Pharmacokinetics of Sunitinib and its Active Metabolite SU012662 in Pediatric Patients with Gastrointestinal Stromal Tumors or Other Solid Tumors.

Background and ObjectivePopulation pharmacokinetic analysis explored the pharmacokinetics of sunitinib and its primary active metabolite, SU012662, in children and evaluated the sunitinib dose(s) that produce comparable plasma exposures to adults receiving the approved daily dose.MethodsData were from 65 children with gastrointestinal stromal tumors (GIST) or solid tumors. Pharmacokinetic models of sunitinib and SU012662 were developed using a systematic multi-step approach employing nonlinear mixed-effects modeling. The effect of predefined covariates on pharmacokinetic parameters was assessed. Final models were validated using visual predictive check and statistical techniques.ResultsThe final dataset comprised 439 sunitinib and 417 SU012662 post-baseline plasma observations. Base models were characterized by two-compartment models with first-order absorption and lag time. Body surface area (BSA) was the only covariate that affected (P < 0.001) pharmacokinetic parameters for sunitinib and SU012662 and was incorporated into the final models. Bootstrap results indicated that the final models represented the final dataset adequately. Based on the final models, a sunitinib dose of ~ 20mg/m2/day in children with GIST aged 6–17 years would be expected to lead to similar total plasma exposures of sunitinib and SU012661 as a dose of 50 mg/day in an adult with GIST on schedule 4/2.ConclusionsIn children with GIST or solid tumors receiving sunitinib, population pharmacokinetic analysis identified BSA as the only covariate that affected pharmacokinetic parameters and predicted a dose of ~ 20 mg/m2/day as achieving equivalent exposure to 50 mg/day in adults with GIST on schedule 4/2.Trial RegistrationClinicalTrials.gov identifiers (date registered): NCT01396148 (July 2011); NCT01462695 (October 2011); NCT00387920 (October 2006).Supplementary InformationThe online version contains supplementary material available at 10.1007/s13318-021-00671-7.

Meta-Analysis of ABCG2 and ABCB1 Polymorphisms With Sunitinib-Induced Toxicity and Efficacy in Renal Cell Carcinoma.

Background: ABCG2 and ABCB1 are genes related to the pharmacokinetics of sunitinib and have been associated with its toxicity and efficacy. However, the results have been controversial. This study aimed to evaluate the associations of ABCG2 and ABCB1 polymorphisms with sunitinib-induced toxicity and efficacy in renal cell carcinoma (RCC) by meta-analysis. Methods: PubMed, EMBASE, Cochrane Library, and Web of Science were systematically searched for studies investigating the associations of the ABCG2 rs2231142 polymorphism with sunitinib-induced toxicity and the associations of the ABCB1 rs1128503 and ABCB1 rs2032582 polymorphisms with sunitinib-induced toxicity and clinical outcomes. The associations were evaluated by effect size (ES) with 95% confidence intervals (CIs). Results: Eight and five studies were included in the toxicity and efficacy analysis, respectively, including a total of 1081 RCC patients. The ABCG2 rs2231142 A allele was associated with an increased risk of sunitinib-induced thrombocytopenia and hand-foot syndrome (HFS) in Asians (ES = 1.65, 95% CI = 1.15–2.36, p = 0.006; ES = 1.52, 95% CI = 1.02–2.27, p = 0.041). However, the ABCG2 rs2231142 polymorphism was not associated with sunitinib-induced hypertension or neutropenia (ES = 1.09, 95% CI = 0.69–1.73, p = 0.701; ES = 0.87, 95% CI = 0.57–1.31, p = 0.501). Compared with the C allele, the ABCB1 rs1128503 T allele was associated with a decreased risk of sunitinib-induced hypertension but worse progression-free survival (PFS) (ES = 0.44, 95% CI = 0.26–0.77, p = 0.004; ES = 1.36, 95% CI = 1.07–1.73, p = 0.011). There was no significant association between the T allele or C allele of ABCB1 rs1128503 and overall survival (OS) (ES = 0.82, 95% CI = 0.61–1.10, p = 0.184). The ABCB1 rs2032582 T allele was associated with worse PFS than the other alleles (ES = 1.46, 95% CI = 1.14–1.87, p = 0.003), while there was no significant association between the T allele or other alleles and sunitinib-induced hypertension, HFS, or OS (ES = 0.77, 95% CI = 0.46–1.29, p = 0.326; ES = 1.02, 95% CI = 0.65–1.62, p = 0.919; ES = 1.32, 95% CI = 0.85–2.05, p = 0.215). Conclusion: The results indicate that the ABCG2 rs2231142 polymorphism may serve as a predictor of sunitinib-induced thrombocytopenia and HFS in Asians, while the ABCB1 rs1128503 polymorphism may serve as a predictor of sunitinib-induced hypertension, and both the ABCB1 rs1128503 and rs2032582 polymorphisms may serve as predictors of PFS in RCC. These results suggest a possible application of individualized use of sunitinib according to the genetic background of patients.

Effects of CYP3A inhibitors ketoconazole, voriconazole, and itraconazole on the pharmacokinetics of sunitinib and its main metabolite in rats

Sunitinib is a small molecule inhibitor of multiple receptor tyrosine kinases such as platelet derived growth factor receptor, vascular endothelial growth factor receptor, kit receptor and other receptors. The US Food and Drug Administration (FDA) has approved sunitinib for the treatment of advanced renal cell carcinoma and gastrointestinal stromal tumors. It has been reported that sunitinib was mainly metabolized by CYP3A but its pharmacokinetic interactions have not been revealed. In this study, we investigated whether CYP3A inhibitors (ketoconazole, voriconazole, and itraconazole) could influence the pharmacokinetics of sunitinib and its equipotent metabolite N-desethyl sunitinib in a drug-drug interaction study in Sprague Dawley (SD) rats. The results showed that ketoconazole and voriconazole significantly increased the exposure of sunitinib, decreased the exposure of N-desethyl sunitinib, and inhibited the metabolism of sunitinib in rats. However, itraconazole showed only a weak effect on pharmacokinetics and metabolism. Coadministration of sunitinib with ketoconazole and voriconazole should be avoided if possible or if not, there should be therapeutic drug monitoring of the levels of sunitinib and N-desethyl sunitinib. Therefore, drug-drug interaction should be considered when sunitinib is administered in conjunction with CYP3A inhibitors, which might lead to toxicity.

Sunitinib in pediatric patients with advanced gastrointestinal stromal tumor: results from a phase I/II trial

BackgroundSunitinib is approved for treatment of adults with imatinib-resistant gastrointestinal stromal tumor (GIST) or imatinib intolerance.MethodsThis single-arm, multicenter, multinational phase I/II clinical trial (NCT01396148) enrolled eligible patients aged 6 to < 18 years with advanced, unresectable GIST with non-mutant KIT, or who demonstrated disease progression or intolerance to imatinib. Patients received sunitinib 15 mg/m2 per day, 4-weeks-on/2-weeks-off (schedule 4/2), for ≤ 18 cycles over 24 months. Intra-patient dose escalation to 22.5 and subsequently 30 mg/m2 were permitted based on individual patient tolerability and supported by real-time pharmacokinetics (PK). Primary objective was PK characterization. Secondary objectives included safety, antitumor activity and PK/pharmacodynamic relationships.ResultsSix patients were enrolled with median (range) age of 14 (13–16) years. All six patients completed at least three treatment cycles, with one completing all 18 cycles. Five patients had a dose increase to 22.5 mg/m2; two of them had a further dose increase to 30 mg/m2. The average daily dose at cycle 3 was 21.1 mg/m2 (n = 6). Steady-state plasma concentrations were reached by day 15, cycle 1. No tumor responses were observed, but three patients had stabilization of the disease (50%). Median progression-free survival was 5.8 months (95% CI 2.3—not reached). There were no serious adverse events.ConclusionsThe tolerable dose of sunitinib in chemotherapy-naïve pediatric patients is at least 20 mg/m2 on schedule 4/2. The safety profile and PK of sunitinib in pediatric patients with GIST are comparable to those in adults.

The influence of light sources on sunitinib measurements with photoisomerization.

Sunitinib is an orally administered tyrosine kinase inhibitor. Therapeutic drug monitoring is an important component of the follow-up of patients because of high interpatient variability in the pharmacokinetics of sunitinib and large variabilities in its efficacy and toxicity. The aim of the present study was to examine the light stability of sunitinib and confirm the effects of light exposure on sunitinib measurements by LC-MS/MS. Sunitinib and its active metabolite, SU12662, convert Z isomers to E isomers with exposure to light. The Z-E photoisomerization ratio reached a plateau at 35% for both E isomers in methanol within 15 min of normal light exposure (700 lx). However, the Z isomer of the sunitinib and SU12662 peak area ratios in plasma decreased by 10% within 15 min. These results suggest that sunitinib samples need to be handled without light exposure in all sample preparation steps. Alternatively, it should be measured sunitinib and SU12662 after the sample has reached photoisomerical equilibrium. These results suggest that the sunitinib therapeutic range changes depending on light conditions during sample handling in sunitinib and SU12662 measurements.

ABCG2 Polymorphism rs2231142 and hypothyroidism in metastatic renal cell carcinoma patients treated with sunitinib

Background and aim: Vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGFR-TKIs) cause significant adverse events including thyroid dysfunction, mainly hypothyroidism, in a considerable proportion of patients. In a series of metastatic renal cell carcinoma (mRCC) patients treated with sunitinib, we aimed to study the correlation between hypothyroidism and single nucleotide polymorphisms (SNPs) in genes involved in sunitinib pharmacokinetics and pharmacodynamics.Patients and methods: We included 79 mRCC patients who started sunitinib between November 2005 and March 2016. Serum thyroid function markers were collected at start and during sunitinib therapy. Germ-line DNA genotyping for 16 SNPs in 8 candidate genes was performed. Endpoints were time to increase in thyroid stimulating hormone (TSH) and time to decrease in T4 or free T4 (FT4) on day 1 and day 28 of each sunitinib cycle.Results: Patients with the ABCG2 rs2231142 CC-genotype had a significantly longer time-to-TSH-increase on day 1 (11 vs. 5 cycles; p = 0.0011), and time-to-T4/FT4-decrease on day 1 (not reached vs. 10 cycles; p = 0.013) and day 28 (28 vs. 7 cycles; p = 0.03) compared to CA-carriers. Patients with the CYP3A5 rs776746 GG-genotype had a significantly longer time-to-TSH-increase at day 1 compared to GA-patients: 11 vs. 5 cycles (p = 0.0071). Significant associations were also found between PDGFRA rs35597368 and rs1800812 and time-to-TSH-increase at day 28.Conclusion: Polymorphism rs2231142 in the efflux pump ABCG2 is associated with hypothyroidism in mRCC patients treated with sunitinib.

Impact of proton pump inhibitors (PPIs) on sunitinib (SU) pharmacokinetics (PK) and activity in GIST patients (pts).

11538Background: PPIs alter the PK of several oral drugs, either through a decrease in absorption due to higher GI tract pH, or the induction of efflux pumps such as ABCB1. The PK of SU is well cor...

The utility of genomics and functional imaging to predict Sunitinib PK and PD: The Predict SU study.

2563Background: Current dosing of Sunitinib (Su) is associated with marked variability in pharmacokinetics (PK) & pharmacodynamics (PD). Despite its hepatic metabolism, genotyping & phenotyping of ...

Clinical implications of pharmacokinetics of sunitinib malate and N-desethyl-sunitinib plasma concentrations for treatment outcome in metastatic renal cell carcinoma patients.

In this study, we examined the association between the pharmacokinetics (PK) level of sunitinib malate (SU) and its metabolite N-desethyl-sunitinib (DSU) in terms of adverse events (AEs) and clinical outcomes in patients with metastatic renal cell carcinoma (mRCC). The PK of sunitinib (SU and DSU) was examined in 26 patients (20 men and 6 women) with mRCC. The associations between SU/DSU C0 and AE occurrence, best response rate, time to treatment failure, progression-free survival (PFS), and overall survival (OS) were investigated. Occurrence of grade 1 or higher hand-foot syndrome and thrombocytopenia (p = 0.002 and 0.024, respectively) was associated with a high concentration before morning intake (C0) level of SU. Low C0 levels of DSU were significantly associated with drug discontinuation due to disease progression (p = 0.035). Patients with DSU C0 level higher than 15.0 ng/mL showed a tendency toward increased PFS (61 weeks vs 12 weeks, p = 0.004) and OS (36 months vs 8 months, p = 0.040). The C0 level of SU and SU + DSU were not associated with prognosis. The higher level of C0 of SU may predict developing AEs and DSU C0 >15.0 ng/mL may lead to better prognosis of patients treated with sunitinib. PK of sunitinib may be useful for determining adequate dosages and prevention of severe AEs. Further studies are required to establish the utility of the PK of sunitinib in patients with mRCC.

Clinical and Biomarker Evaluations of Sunitinib in Patients with Grade 3 Digestive Neuroendocrine Neoplasms

Background/Aims: Angiogenesis is extensively developed in well-differentiated pancreatic neuroendocrine tumours (PanNET) where sunitinib was shown to prolong progression-free survival, leading to nationwide approval. However, clinical experience in patients with grade 3 gastroenteropancreatic neuroendocrine neoplasms (GEPNEN-G3) remains limited. This prospective phase II trial evaluated potential predictive biomarkers of sunitinib activity in patients with advanced GEPNEN-G3. Methods: Sunitinib was given at a dose of 37.5 mg/day as a continuous daily dosing until progression or unacceptable toxicity. Evaluation of activity was based on RECIST1.1. Safety was evaluated according to NCI-CTCAE v4. Pharmacokinetics of sunitinib and its main active metabolite SU12662 were evaluated. All tumour samples were reviewed histologically for tumour differentiation. PDGFRβ, carbonic anhydrase 9, Ki-67, VEGFR2, and p-AKT were quantified using immunohistochemistry and their expression correlated with response by RECIST1.1. Results: Thirty-one patients were included and 26 had available histological tissue. Six and 20 patients presented well-differentiated tumours (NET-G3) and neuroendocrine carcinoma (NEC), respectively. Eighteen patients responded to sunitinib (4 experienced partial responses and 14 tumour stabilization). A high p-AKT expression correlated with lower response to sunitinib (OR 0.94, 95% CI 0.89–0.99, p = 0.04). Safety and PK exposure to sunitinib and SU12662 in these patients were consistent with that reported in PanNET. Conclusion: Sunitinib showed evidence of activity in patients with GEPNEN-G3 with expected toxicity profile. In the NET-G3 and NEC groups, 4/6 and 11/20 patients were responders, respectively. High p-AKT expression predicted a lower response to sunitinib. Our study allowed the identification of a potential biomarker of resistance/sensitivity to sunitinib in aggressive GEPNEN-G3.

Association analysis of SNPs present in plasma with adverse events and population pharmacokinetics in Chinese sunitinib treated patients with renal cell carcinoma.

BackgroundSunitinib is a tyrosine kinase inhibitor with effective therapeutic outcomes in patients with renal-cell carcinoma. The study were to analyze the association of single-nucleotide polymorphisms present in cell-free DNA and pharmacokinetics with sunitinib treatment-emergent adverse events in Chinese patients with renal-cell carcinoma.Materials and MethodsWe genotyped 8 keys SNPs in 6 candidate genes. The plasma concentrations of sunitinib and N-desethyl sunitinib were measured using a high performance liquid chromatography-tandam mass spectrometry method. Correlations between the single-nucleotide polymorphisms and adverse events were investigated by univariate and multivariate logistic regression and we quantitatively evaluated the effect of single-nucleotide polymorphisms on the pharmacokinetics of sunitinib by using a population PK model.ResultsNecessary dose reductions of sunitinib were significantly correlated with SNP rs1933437 in FLT3. A higher severity of AEs were collected with SNP rs2032582 in ABCB1 and rs1800812 in PDGFRα. Thrombocytopenia was collected with rs1800812 in PDGFRα. Our study provides a population PK model of sunitinib with the ABCB1 genotype as a predictive covariate for apparent oral clearance.ConclusionsOur study preliminarily confirmed the hypothesis that the pharmacokinetics of sunitinib is affected by the SNPs of enzyme in Chinese renal-cell carcinoma patients, and this affects the different distribution and severity of adverse events of sunitinib.

MP16-01 CLINICAL IMPLICATIONS OF SUNITINIB AND N-DESETHYL-SUNITINIB PLASMA CONCENTRATIONS FOR TREATMENT OUTCOME IN METASTATIC RENAL CELL CARCINOMA PATIENTS

You have accessJournal of UrologyKidney Cancer: Advanced (including Drug Therapy) II1 Apr 2017MP16-01 CLINICAL IMPLICATIONS OF SUNITINIB AND N-DESETHYL-SUNITINIB PLASMA CONCENTRATIONS FOR TREATMENT OUTCOME IN METASTATIC RENAL CELL CARCINOMA PATIENTS Kazuyuki Numakura, Nobuhiro Fujiyama, Makoto Takahashi, Hiroshi Tsuruta, Atsushi Maeno, Mitsuru Saito, Takamitsu Inoue, Shintaro Narita, Mingguo Huang, Shigeru Satoh, Takenori Niioka, Masatomo Miura, and Tomonori Habuchi Kazuyuki NumakuraKazuyuki Numakura More articles by this author , Nobuhiro FujiyamaNobuhiro Fujiyama More articles by this author , Makoto TakahashiMakoto Takahashi More articles by this author , Hiroshi TsurutaHiroshi Tsuruta More articles by this author , Atsushi MaenoAtsushi Maeno More articles by this author , Mitsuru SaitoMitsuru Saito More articles by this author , Takamitsu InoueTakamitsu Inoue More articles by this author , Shintaro NaritaShintaro Narita More articles by this author , Mingguo HuangMingguo Huang More articles by this author , Shigeru SatohShigeru Satoh More articles by this author , Takenori NiiokaTakenori Niioka More articles by this author , Masatomo MiuraMasatomo Miura More articles by this author , and Tomonori HabuchiTomonori Habuchi More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.507AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Therapeutic drug monitoring (TDM) has been recognized as a useful tool for optimizing the dosages of many drugs, even in molecular-targeted therapeutics. In this study, we examined the associations between the pharmacokinetics of sunitinib (SU) and its metabolite N-desethyl-sunitinib (DSU) and adverse events (AEs) and clinical outcomes in patients with metastatic renal cell carcinoma (mRCC). METHODS The pharmacokinetics of SU and DSU were examined in 26 patients (20 male and 6 female patients) with mRCC. Plasma SU and DSU levels were measured using high-performance liquid chromatography, and a pharmacokinetic study was performed on day 7 in the first cycle of SU. The associations between SU/DSU pharmacokinetics and the occurrence of AEs, best response rate, progression-free survival (PFS), time to treatment failure (TTF), and overall survival (OS) were investigated. RESULTS All patients were treated with 37.5 mg/day SU at the day of pharmacokinetics. The mean trough levels of SU and DSU were 76.7 and 16.8 ng/mL respectively. Occurrence of hand-foot syndrome and thrombocytopenia (P = 0.002 and 0.024 respectively by Mann-Whitney test) was associated with high trough levels of SU. Low trough levels of DSU were significantly associated with drug discontinuation due to disease progression and were associated with worse tumor response (P = 0.035 and 0.042 respectively by Mann-Whitney test, Figure 1). Patients with DSU trough levels of or higher than 15.0 ng/mL showed a tendency toward increased PFS, TTF, and OS than those with trough levels lower than 15.0 ng/mL (Figure 2). SU trough levels were not associated with prognosis. CONCLUSIONS TDM of SU and DSU in patients with mRCC may be useful to determine adequate dosages and prevent severe AEs. Further studies are required to establish the usefulness of TDM of SU and DSU for ensuring long-term clinical efficacy in patients with mRCC. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e179 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Kazuyuki Numakura More articles by this author Nobuhiro Fujiyama More articles by this author Makoto Takahashi More articles by this author Hiroshi Tsuruta More articles by this author Atsushi Maeno More articles by this author Mitsuru Saito More articles by this author Takamitsu Inoue More articles by this author Shintaro Narita More articles by this author Mingguo Huang More articles by this author Shigeru Satoh More articles by this author Takenori Niioka More articles by this author Masatomo Miura More articles by this author Tomonori Habuchi More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Impact of pharmacokinetics (PK) of sunitinib (SU) and its metabolite SU12662 on clinical outcome and toxicity in metastatic renal cell cancer (mRCC) patients.

506 Background: Pharmacological activity of SU is usually attributed to SU and its active metabolite SU12662, known to exhibit similar potency in inhibiting tyrosine kinase activity and cellular proliferation in vitro. However, equivalence is not clearly demonstrated towards clinical endpoints. The objective of this phase 2 study was to determine the impact of SU and SU12662 on clinical outcomes and toxicity in mRCC patients (NCT00943839). Methods: Patients with mRCC, eligible for SU in the first line setting, were prospectively included. SU was given orally at 50 mg qd for 4 weeks on/2 weeks off until progression or unacceptable toxicity. Minimal concentration at steady-state (CSSmin) was evaluated by high-performance liquid chromatography at day 28 of each cycle for both SU and SU12662. Data for tumor response, survival, and toxicity were recorded. Kaplan-Meyer’s curves with log-rank tests and cox regression models were used to identify relationships between PK parameters and survival. Chi2 tests and student t-tests were used to identify relationships with toxicity. Results: 41 patients in 7 French centers were included between 2009 and 2012. 16 patients had favourable prognosis, 13 intermediate prognosis, and 1 poor prognosis according to IMDC risk groups (Heng, J Clin Oncol 2009). Median follow-up was 30.6 months. Median progression-free survival (PFS) was 20.2 months and median overall survival (OS) was 39.5 months. Mean CSSmin for SU and SU12662 were 57.2 and 29.8 ng/ml, respectively. CSSmin of SU12662 was independently correlated to poor PFS and OS (p = 0.01 and 0.003 respectively). Patients with a mean CSSmin of SU12662 higher than 42.5 ng/ml had a worse PFS and OS compared to patients with lower concentrations: 5.7 months and 5.7 months versus 20.6 months and 39.5 months (p = 0.01 and 0.002 respectively). High CSSmin of both SU and SU12662 were associated with increased incidence of asthenia (p&lt;0.001). Conclusions: High exposure to SU12662 was associated with poor outcomes and increased asthenia for patients with mRCC treated with SU in the first line setting. It may be related to a higher metabolism and unequal activity between SU and SU12662 in vivo. Clinical trial information: NCT00943839.

Severe toxicity induced by accumulation of active sunitinib metabolite in a Japanese patient with renal cell carcinoma: a case report

BackgroundSunitinib is a multi-targeted tyrosine kinase inhibitor that is approved for treatment of renal cell carcinoma as an oral anticancer drug. Therapeutic drug monitoring of total sunitinib (sunitinib and N-desethyl sunitinib) is used in our hospital to improve therapeutic efficacy, while preventing adverse effects. Here, we report the first case of a patient with metastatic renal cell carcinoma undergoing hemodialysis and presenting severe adverse events induced by the accumulation of N-desethyl sunitinib.Case presentationA 60-year-old Japanese man was diagnosed with metastatic renal cell carcinoma requiring hemodialysis. On day 26 of the first cycle of sunitinib therapy, our patient presented grade 3 thrombocytopenia and leukopenia, which required interruption of therapy although the plasma levels of total sunitinib in the patient were less than the effective concentration of 50 ng/mL. The elimination half-life of sunitinib was normal at 50.8 hours, but that of N-desethyl sunitinib was an extended 211.4 hours. Moreover, the N-desethyl sunitinib/sunitinib trough level ratio was higher than 1.0. We attribute our patient’s severe adverse events to the excessive accumulation of N-desethyl sunitinib owing to its delayed excretion. Although the reason for the delayed excretion of N-desethyl sunitinib in this patient was unknown, it may have been caused by genetic polymorphisms related to the pharmacokinetics of sunitinib rather than the hemodialysis. In this case, the patient was homozygous for the ABCG2 421C allele, but was capable of potentially harboring polymorphisms in other genes, such as ABCB1, an efflux pump of sunitinib. In addition, even though there is no clear evidence, urinary excretion of the metabolic products of N-desethyl sunitinib could be inhibited by the interaction of transporters such as the organic ion transporter.ConclusionsThe monitoring of not only total sunitinib concentration but also N-desethyl sunitinib concentration and their elimination half-lives during sunitinib therapy is recommended to avoid critical adverse events.

Clinical effects of single nucleotide polymorphisms on drug-related genes in Japanese metastatic renal cell carcinoma patients treated with sunitinib.

Although sunitinib is a well-established chemotherapeutic for metastatic renal cell carcinoma (mRCC), there are no robust markers that predict efficacy and toxicity. We analyzed the effect of single nucleotide polymorphisms (SNPs) in genes involved in sunitinib pharmacokinetics on clinical outcomes in Japanese patients with mRCC. We analyzed the effect of SNPs in genes involved in sunitinib pharmacokinetics on the clinical outcome in mRCC patients in a Japanese population. We evaluated seven SNPs in four candidate genes, the transport proteins ATP-binding cassette (ABC) B1 (rs1045642, rs1128503, rs2032582, and rs7779562) and ABCG2 (rs2231142), and the metabolic proteins cytochrome P450 (CYP) 3A4 (rs35599367) and CYP3A5 (rs776746) in 70 patients. No significant association was observed between the genotypes of each SNP and time to dose reduction, progression-free survival, overall survival, and best objective response. Meanwhile, the incidence of grade 2 or greater hypertension and hand-foot syndrome, and multiple adverse events (>3), was significantly higher in patients carrying the ABCB1 rs2032582 GG genotype [odds ratio (OR): 5.37, 95% confidence interval (CI) 1.02-14.63, P=0.035; OR: 3.17, 95% CI 1.06-9.52, P=0.036, OR: 3.35; 95% CI 1.14-9.84; P=0.025, respectively]. In conclusion, our data showed that the ABCB1 rs2032582 GG genotype was associated with individual adverse events' susceptibility among Japanese patients treated with sunitinib in routine clinical settings.

PCN9 - Factors Influencing the Pharmacokinetics of Sunitinib and its Active Metabolite in MRCC Patients Receiving an Attenuated Sunitinib Dosing Regimen

PCN9 - Factors Influencing the Pharmacokinetics of Sunitinib and its Active Metabolite in MRCC Patients Receiving an Attenuated Sunitinib Dosing Regimen

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.

Clinical and biomarker evaluations of sunitinib in patients (pts) with advanced well-differentiated grade 3 (G3) and poorly differentiated neuroendocrine neoplasms (PD-NEN).

274 Background: Angiogenesis is extensively developed in well-differentiated pancreatic neuroendocrine tumors (PNET) where sunitinib was showed to prolong progression-free survival leading to FDA and EMA approval. However, clinical experience in pts with well-differentiated G3 &amp; PD-NEN remains limited. Methods: This prospective phase II trial evaluate potential biomarkers correlating with sunitinib activity in pts with advanced well differentiated G3 or PD-NEN. Sunitinib was given at the dose of 37.5 mg/d as a continuous daily dosing until progression or unacceptable toxicity. Evaluation of activity was based on RECIST1.1. Safety was evaluated according to NCI-CTCAEv4. Pharmacokinetics (PK) of sunitinib and SU12662 (main active metabolite) were evaluated. Tumor biomarkers (PDGFR-b, VEGFR2, Carbonic Anhydrase 9, Ki67 and p-AKT) were evaluated in tumor tissues, quantified in tumor cells and stroma (vessels, fibroblasts) using immunohistochemistry and correlated with response by RECIST. Results: Among 31 pts (M/F: 18/13, median age 61), 13 pancreatic, 5 gastric, 5 rectal, 4 colonic, and 4 other G3 &amp; PD-NEN were entered. 27 pts had previous treatment with chemotherapy (mainly platinum/VP16). Among 26 pts evaluable for safety and activity, 7 pts (23%, 95%CI: 6.9%-39.3%), including 3 pts classified as well-differentiated G3 neoplasms) experienced partial responses and tumor stabilizations (clinical benefit). Safety and PK exposure to sunitinib and SU12662 in those pts was consistent with that experienced in PNET. Among the above evaluated tumor biomarkers, only Ki67 correlated with sunitinib activity. The median Ki67 was 20% and 77.5% in pts with CB versus non-responders (p=.002), respectively. ROC curves showed correlations between lower Ki67 in tumors and sunitinib activity (OR:0.9; IC95%:0.831-0.9, p=.039). With a threshold value of Ki67 of 47%, sensitivity and specificity were 80%, the predictive positive value was 67% and the negative predictive value was 86%. Conclusions: In pts with well-differentiated G3 &amp; PD-NEN, sunitinib showed evidence of activity that was more pronounced in pts with Ki67&lt;47%. Clinical trial information: NCT01215578.

Sunitinib-ibuprofen drug interaction affects the pharmacokinetics and tissue distribution of sunitinib to brain, liver, and kidney in male and female mice differently.

Tyrosine kinase inhibitor sunitinib (used in GIST, advanced RCC, and pancreatic neuroendocrine tumors) undergoes CYP3A4 metabolism and is an ABCB1B and ABCG2 efflux transporters substrate. We assessed the pharmacokinetic interaction with ibuprofen (an NSAID used by patients with cancer) in Balb/c male and female mice. Mice (study group) were coadministered (30 min apart) 30 mg/kg of ibuprofen and 60 mg/kg of sunitinib PO and compared with the control groups, which received sunitinib alone (60 mg/kg, PO). Sunitinib concentration in plasma, brain, kidney, and liver was measured by HPLC as scheduled and noncompartmental pharmacokinetic parameters estimated. In female control mice, sunitinib AUC0→∞ decreased in plasma (P < 0.05), was higher in liver and brain (P < 0.001), and lower in kidney (P < 0.001) vs. male control mice. After ibuprofen coadministration, female mice showed lower AUC0→∞ in plasma (P < 0.01), brain, liver, and kidney (all P < 0.001). However, in male mice, AUC0→∞ remained unchanged in plasma, increased in liver and kidney, and decreased in brain (all P < 0.001). The tissue-to-plasma AUC0→∞ ratio was similar between male and female control mice, but changed after ibuprofen coadministration: Male mice showed 1.6-fold higher liver-to-plasma ratio (P < 0.001) while remained unchanged in female mice and in kidney (male and female mice) but decreased 55% in brain (P < 0.05). The tissue-to-plasma partial AUC ratio, the drug tissue targeting index, and the tissue-plasma hysteresis-like plots also showed sex-based ibuprofen-sunitinib drug interaction differences. The results illustrate the relevance of this DDI on sunitinib pharmacokinetics and tissue uptake. These may be due to gender-based P450 and efflux/transporters differences.