Docetaxel and irinotecan in recurrent or metastatic head and neck cancer

Background: Docetaxel and irinotecan have single-agent antitumor activity in squamous cell carcinoma of the head and neck (SCCHN). The authors sought to evaluate their combination in the treatment of patients with recurrent or metastatic SCCHN. Methods: Eligibility criteria included recurrent or metastatic SCCHN with measurable disease, good performance status, and adequate laboratory parameters. Patients received docetaxel 35 mg/m2 and irinotecan 60 mg/m2, intravenously, on Days 1 and 8, every 21 days, until disease progression. The authors assessed UGT1A1 genotype, vascular endothelial growth factor (VEGF) in serum, and cyclooxygenase-2 and VEGF in baseline tumor tissue. Results: Fifty-two patients were analyzable: 20 chemotherapy naive (Group A) and 32 previously treated with 1 chemotherapy regimen (Group B); 73% of patients had distant metastasis, and 60% were paclitaxel-exposed. In Group A, 3 (15%) patients achieved a partial response; in Group B, 1 (3%) patient achieved a partial response. Median progression-free survival (PFS) and overall survival were 3.3 and 8.2 months in Group A and 1.9 and 5.0 months in Group B, respectively. Common serious toxicities were diarrhea, fatigue, and anorexia. Patients with high serum VEGF had a median PFS of 2.8 months versus 1.7 months for patients with low VEGF (P = .085). Conclusions: Docetaxel and irinotecan had acceptable toxicities, but efficacy results in unselected patients with recurrent or metastatic SCCHN did not suggest an advantage over docetaxel alone or platinum-based regimens. Cancer 2009. © 2009 American Cancer Society

Astaxanthin in Exercise Metabolism, Performance and Recovery: A Review

During periods of heavy exercise training and competition, lipid, protein and nucleic molecules can become damaged due to an overproduction of reactive oxygen and nitrogen species within the exercising organism. As antioxidants can prevent and delay cellular oxidative damage through removing, deactivating and preventing the formation of reactive oxygen and nitrogen species, supplementation with exogenous antioxidant compounds has become a commercialised nutritional strategy commonly adopted by recreationally active individuals and athletes. The following review is written as a critical appraisal of the current literature surrounding astaxanthin and its potential application as a dietary supplement in exercising humans. Astaxanthin is a lipid-soluble antioxidant carotenoid available to supplement through the intake of Haematococcus pluvialis-derived antioxidant products. Based upon in vitro and in vivo research conducted in mice exercise models, evidence would suggest that astaxanthin supplementation could potentially improve indices of exercise metabolism, performance and recovery because of its potent antioxidant capacity. In exercising humans, however, these observations have yet to be consistently realised, with equivocal data reported. Implicated, in part, by the scarcity of well-controlled, scientifically rigorous research, future investigation is necessary to enable a more robust conclusion in regard to the efficacy of astaxanthin supplementation and its potential role in substrate utilisation, endurance performance and acute recovery in exercising humans

Astaxanthin: A Potential Therapeutic Agent in Cardiovascular Disease

Astaxanthin is a xanthophyll carotenoid present in microalgae, fungi, complex plants, seafood, flamingos and quail. It is an antioxidant with anti-inflammatory properties and as such has potential as a therapeutic agent in atherosclerotic cardiovascular disease. Synthetic forms of astaxanthin have been manufactured. The safety, bioavailability and effects of astaxanthin on oxidative stress and inflammation that have relevance to the pathophysiology of atherosclerotic cardiovascular disease, have been assessed in a small number of clinical studies. No adverse events have been reported and there is evidence of a reduction in biomarkers of oxidative stress and inflammation with astaxanthin administration. Experimental studies in several species using an ischaemia-reperfusion myocardial model demonstrated that astaxanthin protects the myocardium when administered both orally or intravenously prior to the induction of the ischaemic event. At this stage we do not know whether astaxanthin is of benefit when administered after a cardiovascular event and no clinical cardiovascular studies in humans have been completed and/or reported. Cardiovascular clinical trials are warranted based on the physicochemical and antioxidant properties, the safety profile and preliminary experimental cardiovascular studies of astaxanthin

Astaxanthin vs placebo on arterial stiffness, oxidative stress and inflammation in renal transplant patients (Xanthin): a randomised controlled trial

Background: There is evidence that renal transplant recipients have accelerated atherosclerosis manifest by increased cardiovascular morbidity and mortality. The high incidence of atherosclerosis is, in part, related to increased arterial stiffness, vascular dysfunction, elevated oxidative stress and inflammation associated with immunosuppressive therapy. The dietary supplement astaxanthin has shown promise as an antioxidant and anti-inflammatory therapeutic agent in cardiovascular disease. The aim of this trial is to investigate the effects of astaxanthin supplementation on arterial stiffness, oxidative stress and inflammation in renal transplant patients

Prediction of irinotecan and 5-fluorouracil toxicity and response in patients with advanced colorectal cancer

Irinotecan and 5-fluorouracil (5-FU) are used to treat metastatic colorectal cancer. Irinotecan's active metabolite is inactivated by UDP-glucuronosyltransferase 1A1 (UGT1A1), which is deficient in Gilbert's syndrome. Irinotecan and metabolites are transported by P-glycoprotein, encoded by ABCB1. 5-FU targets folate metabolism through inhibition of thymidylate synthase (TYMS). Methylenetetrahydrofolate reductase (MTHFR) generates active folate necessary for haematopoiesis. We retrospectively genotyped 140 Swedish and Norwegian irinotecan and 5-FU-treated colorectal cancer patients from the Nordic VI clinical trial for selected variants of UGT1A1, ABCB1, TYMS and MTHFR. We found an increased risk of clinically relevant early toxicity in patients carrying the ABCB1 3435 T/T genotype, Odds ratio (OR)=3.79 (95% confidence interval (CI)=1.09–13.2), and in patients carrying the UGT1A1*28/*28 genotype, OR=4.43 (95% CI=1.30–15.2). Patients with UGT1A1*28/*28 had an especially high risk of neutropenia, OR=6.87 (95% CI=1.70–27.7). Patients who had reacted with toxicity during the first two cycles were in total treated with fewer cycles (P<0.001), and less often responded to treatment (P<0.001). Genetic variation in ABCB1 was associated with both early toxicity and lower response to treatment. Carriers of the ABCB1 1236T-2677T-3435T haplotype responded to treatment less frequently (43 vs 67%, P=0.027), and survived shorter time, OR=1.56 (95% CI=1.01–2.45)

Digital Quantification of Human Eye Color Highlights Genetic Association of Three New Loci

Previous studies have successfully identified genetic variants in several genes associated with human iris (eye) color; however, they all used simplified categorical trait information. Here, we quantified continuous eye color variation into hue and saturation values using high-resolution digital full-eye photographs and conducted a genome-wide association study on 5,951 Dutch Europeans from the Rotterdam Study. Three new regions, 1q42.3, 17q25.3, and 21q22.13, were highlighted meeting the criterion for genome-wide statistically significant association. The latter two loci were replicated in 2,261 individuals from the UK and in 1,282 from Australia. The LYST gene at 1q42.3 and the DSCR9 gene at 21q22.13 serve as promising functional candidates. A model for predicting quantitative eye colors explained over 50% of trait variance in the Rotterdam Study. Over all our data exemplify that fine phenotyping is a useful strategy for finding genes involved in human complex traits

Studies on intrinsic and extrinsic sources of variability in pharmacokinetics and pharmacodynamics

Variability in pharmacokinetic and pharmacodynamic parameters between individuals can be due to intrinsic and extrinsic factors. In this thesis three different areas regarding sources of variability have been investigated. 1. Formulation properties as an extrinsic source of variability. Lipophilic substances often have poor oral bioavailability and high inter- and intraindividual variability. High fat meals can increase the bioavailability. Two lipophilic substances, astaxanthin and cyclosporine, were incorporated in different lipid based formulations, given orally to healthy volunteers, and shown to alter the bioavailability when compared to reference substances. The combination of different lipid excipients, their ratios and the degree of drug incorporation were factors shown to affect the drug bioavailability. The use of a rational formulation approach in the study with cyclosporine gave successful information in a limited number of trials. 2. Intrinsic and extrinsic sources of variability in the pharmacokinetics and pharmacodynamic of desmopressin. To evaluate factors that can cause variability both the pharmacokinetics and pharmacodynamics have to be investigated. Desmopressin is a synthetic analogue of the antidiuretic hormone vasopressin. We studied in humans if different levels of water hydration had any influence on especially the pharmacokinetics, and found no statistical evidence for that. An indirect response model was described and verified for the concentration-effect relationship. Further, we investigated sex differences and the impact of concomitant medication with piroxicam , and we found a difference in the pharmacodynamics of desmopressin, but not in the pharmacokinetics. 3. Genetic polymorphism as an intrinsic source of variability in drug metabolism and drug transport. We investigated, in a Swedish cohort (248 individuals) and in a human diversity panel (HDP) (DNA from 14 ethnicities), the prevalence of different polymorphisms and haplotypes in the UGT1A- and MDR1-genes, both being associated with variations in pharmacokinetics. Also, to estimate UGT1A genotype-dependent glucuronidation efficiency, we used the endogenous substrate bilirubin as an indicator. We found that several of the genetic variants investigated in the UGT1A-gene and also the SNP (exon 26, C3435T) in the MDR1 gene are common in the cohort. The HDP indicated differences in prevalence of the allelic variants due to ethnicity. Three major haplotypes of the UGT1A-gene constitute 84% of the allelic variants. Tools for optimisation, prediction and individualisation of drug treatment are important for attaining the aim of explaining and reducing variability in drug response