189 research outputs found
Severe clinical toxicities are correlated with survival in patients with advanced renal cell carcinoma treated with sunitinib and sorafenib
Effect of ketoconazole on the pharmacokinetics of axitinib in healthy volunteers
Objective Axitinib (AG-013736), an oral, potent, and selective inhibitor of vascular endothelial growth factor receptors 1, 2, and 3, is metabolized primarily by cytochrome P450 (CYP) 3A with minor contributions from CYP1A2, CYP2C19, and glucuronidation. Co-administration with CYP inhibitors may increase systemic exposure to axitinib and alter its safety profile. This study evaluated changes in axitinib plasma pharmacokinetic parameters and assessed safety and tolerability in healthy subjects, following axitinib co-administration with the potent CYP3A inhibitor ketoconazole. Methods In this randomized, single-blind, two-way crossover study, 32 healthy volunteers received placebo, followed by a single 5-mg oral dose of axitinib, administered either alone or on the fourth day of dosing with oral ketoconazole (400 mg/day for 7 days). Results Axitinib exposure was significantly increased in the presence of ketoconazole, with a geometric mean ratio for area under the plasma concentration–time curve from time zero to infinity of 2.06 (90% confidence interval [CI]: 1.84–2.30) and a geometric mean ratio for maximum plasma concentration (Cmax) of 1.50 (90% CI: 1.33–1.70). For axitinib alone or with ketoconazole, Cmax occurred 1.5 and 2.0 h after dosing, respectively. Adverse events were predominantly mild; the most commonly reported treatment-related adverse events were headache and nausea. Conclusions Axitinib plasma exposures and peak concentrations were increased following concurrent administration of axitinib and ketoconazole in healthy volunteers. Axitinib alone and in combination with ketoconazole was well tolerated. These findings provide an upper exposure for expected axitinib plasma concentrations in the presence of potent metabolic inhibition
Blood glucose levels in patients with metastatic renal cell carcinoma treated with sunitinib
Sunitinib, a multitargeted tyrosine-kinase inhibitor, extends survival of patients with metastatic renal cell carcinoma (mRCC) and gastrointestinal stromal tumours. Between October 2005 and March 2007, we retrospectively reviewed blood glucose level variations associated with sunitinib therapy in patients treated for mRCC. Nineteen of the patients had type II diabetes. All 19 patients had a decrease in blood glucose level (mean 1.77 mmol l−1) after 4 weeks of treatment. This was followed by re-elevation in the 2-week rest period. After two cycles of sunitinib administration, two patients had stopped blood glucose-lowering drugs whereas five other patients had normalised their blood glucose level. On the basis of pre-clinical data, we hypothesise that several mechanisms could be involved in this process, such as capillary regression of pancreatic islets, IGF-1 modulation through HIF1-α or NF-κB activation. In addition, a decrease of glucose uptake in the context of concomitant gastrointestinal toxicity cannot be excluded. Glycaemic control should be carefully evaluated in diabetic patients treated with sunitinib, and routine monitoring is warranted
Oxaliplatin induces drug resistance more rapidly than cisplatin in H69 small cell lung cancer cells
Cisplatin produces good responses in solid tumours including small cell lung cancer (SCLC) but this is limited by the development of resistance. Oxaliplatin is reported to show activity against some cisplatin-resistant cancers but there is little known about oxaliplatin in SCLC and there are no reports of oxaliplatin resistant SCLC cell lines. Studies of drug resistance mainly focus on the cellular resistance mechanisms rather than how the cells develop resistance. This study examines the development of cisplatin and oxaliplatin resistance in H69 human SCLC cells in response to repeated treatment with clinically relevant doses of cisplatin or oxaliplatin for either 4 days or 2h. Treatments with 200ng/ml cisplatin or 400ng/ml oxaliplatin for 4 days produced sublines (H69CIS200 and H69OX400 respectively) that showed low level (approximately 2-fold) resistance after 8 treatments. Treatments with 1000ng/ml cisplatin or 2000ng/ml oxaliplatin for 2h also produced sublines, however these were not stably resistant suggesting shorter treatment pulses of drug may be more effective. Cells survived the first five treatments without any increase in resistance, by arresting their growth for a period and then regrowing. The period of growth arrest was reduced after the sixth treatment and the H69CIS200 and H69OX400 sublines showed a reduced growth arrest in response to cisplatin and oxaliplatin treatment suggesting that "regrowth resistance" initially protected against drug treatment and this was further upregulated and became part of the resistance phenotype of these sublines. Oxaliplatin dose escalation produced more surviving sublines than cisplatin dose escalation but neither set of sublines were associated with increased resistance as determined by 5-day cytotoxicity assays, also suggesting the involvement of regrowth resistance. The resistant sublines showed no change in platinum accumulation or glutathione levels even though the H69OX400 subline was more sensitive to buthionine sulfoximine treatment. The H69CIS200 cells were cross-resistant to oxaliplatin demonstrating that oxaliplatin does not have activity against low level cisplatin resistance. Relative to the H69 cells, the H69CIS200 and H69OX400 sublines were more sensitive to paclitaxel and taxotere suggests the taxanes may be useful in the treatment of platinum resistant SCLC. These novel cellular models of cisplatin and oxaliplatin resistant SCLC will be useful in developing strategies to treat platinum-resistant SCLC
Targeting Angiogenesis with Multitargeted Tyrosine Kinase Inhibitors in the Treatment of Non-Small Cell Lung Cancer
The article reviews the current developmental status of antiangiogenic tyrosine kinase inhibitors (including vandetanib, sunitinib, axitinib, sorafenib, vatalanib, and pazopanib) in non-small cell lung cancer and discusses the need for optimal patient selection and potential future directions
Organometallic iridium(III) anticancer complexes with new mechanisms of action: NCI-60 screening, mitochondrial targeting, and apoptosis
Platinum complexes related to cisplatin, cis-[PtCl2(NH3)2], are successful anticancer drugs; however, other transition metal complexes offer potential for combating cisplatin resistance, decreasing side effects, and widening the spectrum of activity. Organometallic half-sandwich iridium (IrIII) complexes [Ir(Cpx)(XY)Cl]+/0 (Cpx = biphenyltetramethylcyclopentadienyl and XY = phenanthroline (1), bipyridine (2), or phenylpyridine (3)) all hydrolyze rapidly, forming monofunctional G adducts on DNA with additional intercalation of the phenyl substituents on the Cpx ring. In comparison, highly potent complex 4 (Cpx = phenyltetramethylcyclopentadienyl and XY = N,N-dimethylphenylazopyridine) does not hydrolyze. All show higher potency toward A2780 human ovarian cancer cells compared to cisplatin, with 1, 3, and 4 also demonstrating higher potency in the National Cancer Institute (NCI) NCI-60 cell-line screen. Use of the NCI COMPARE algorithm (which predicts mechanisms of action (MoAs) for emerging anticancer compounds by correlating NCI-60 patterns of sensitivity) shows that the MoA of these IrIII complexes has no correlation to cisplatin (or oxaliplatin), with 3 and 4 emerging as particularly novel compounds. Those findings by COMPARE were experimentally probed by transmission electron microscopy (TEM) of A2780 cells exposed to 1, showing mitochondrial swelling and activation of apoptosis after 24 h. Significant changes in mitochondrial membrane polarization were detected by flow cytometry, and the potency of the complexes was enhanced ca. 5× by co-administration with a low concentration (5 μM) of the γ-glutamyl cysteine synthetase inhibitor L-buthionine sulfoximine (L-BSO). These studies reveal potential polypharmacology of organometallic IrIII complexes, with MoA and cell selectivity governed by structural changes in the chelating ligands
Brain natriuretic peptide precursor (NT-pro-BNP) levels predict for clinical benefit to sunitinib treatment in patients with metastatic renal cell carcinoma
<p>Abstract</p> <p>Background</p> <p>Sunitinib is an oral, multitargeted tyrosine kinase inhibitor that has been approved for the treatment of metastatic renal cell carcinoma. Although the majority of sunitinib-treated patients receive a clinical benefit, almost a third of the patients will not respond. Currently there is no available marker that can predict for response in these patients.</p> <p>Methods</p> <p>We estimated the plasma levels of NT-pro-BNP (the N-terminal precursor of brain natriuretic peptide) in 36 patients that were treated with sunitinib for metastatic clear-cell renal carcinoma.</p> <p>Results</p> <p>From the 36 patients, 9 had progressive disease and 27 obtained a clinical benefit (objective response or disease stabilization). Increases in plasma NT-pro-BNP were strongly correlated to clinical outcome. Patients with disease progression increased plasma BNP at statistically significant higher levels than patients that obtained a clinical benefit, and this was evident from the first 15 days of treatment (a three-fold increase in patients with progressive disease compared to stable NT-pro-BNP levels in patients with clinical benefit, p < 0.0001). Median progression-free survival was 12.0 months in patients with less than 1.5 fold increases (n = 22) and 3.9 months in patients with more than 1.5 fold increases in plasma NT-pro-BNP (n = 13) (log-rank test, p = 0.001).</p> <p>Conclusions</p> <p>This is the first time that a potential "surrogate marker" has been reported with such a clear correlation to clinical benefit at an early time of treatment. Due to the relative small number of accessed patients, this observation needs to be further addressed on larger cohorts. More analyses, including multivariate analyses are needed before such an observation can be used in clinical practice.</p
Soluble Isoforms of Vascular Endothelial Growth Factor Are Predictors of Response to Sunitinib in Metastatic Renal Cell Carcinomas
Angiogenesis is the target of several agents in the treatment of malignancies, including renal cell carcinoma (RCC). There is a real need for surrogate biomarkers that can predict selection of patients who may benefit from antiangiogenic therapies, prediction of disease outcome and which may improve the knowledge regarding mechanism of action of these treatments. Tyrosine kinase inhibitors (TKI) have proven efficacy in metastatic RCC (mRCC). However, the molecular mechanisms underlying the clinical response to these drugs remain unclear.The present study aimed to identify molecular biomarkers associated with the response to sunitinib, a Tyrosine kinase inhibitor. To evaluate this relationship, primary tumors from 23 metastatic RCC patients treated by sunitinib were analyzed for a panel of 16 biomarkers involved in tumor pathways targeted by sunitinib, using real-time quantitative reverse-transcriptase PCR. Nine of the 23 patients (39%) responded to sunitinib. Among transcripts analyzed, only the levels of vascular endothelial growth factor (VEGF) soluble isoforms (VEGF(121) and VEGF(165)) were associated with the response to sunitinib (P = 0.04 for both). Furthermore, the ratio of VEGF soluble isoforms (VEGF(121)/VEGF(165)) was significantly associated with prognosis (P = 0.02).This preliminary study provides a promising tool that might help in the management of metastatic RCC, and could be extended to other tumors treated by TKI
A model of hypertension and proteinuria in cancer patients treated with the anti-angiogenic drug E7080
Hypertension and proteinuria are commonly observed side-effects for anti-angiogenic drugs targeting the VEGF pathway. In most cases, hypertension can be controlled by prescription of anti-hypertensive (AH) therapy, while proteinuria often requires dose reductions or dose delays. We aimed to construct a pharmacokinetic–pharmacodynamic (PK–PD) model for hypertension and proteinuria following treatment with the experimental VEGF-inhibitor E7080, which would allow optimization of treatment, by assessing the influence of anti-hypertensive medication and dose reduction or dose delays in treating and avoiding toxicity. Data was collected from a phase I study of E7080 (n = 67), an inhibitor of multiple tyrosine kinases, among which VEGF. Blood pressure and urinalysis data were recorded weekly. Modeling was performed in NONMEM, and direct and indirect response PK–PD models were evaluated. A previously developed PK model was used. An indirect response PK–PD model described the increase in BP best, while the probability of developing proteinuria toxicity in response to exposure to E7080, was best described by a Markov transition model. This model may guide clinical interventions and provide treatment recommendations for E7080, and may serve as a template model for other drugs in this class
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