| 1. |
- de Graan, Anne-Joy M., et al.
(författare)
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A Pharmacogenetic Predictive Model for Paclitaxel Clearance Based on the DMET Platform
- 2013
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Ingår i: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 19:18, s. 5210-5217
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Paclitaxel is used in the treatment of solid tumors and displays high interindividual variation in exposure. Low paclitaxel clearance could lead to increased toxicity during treatment. We present a genetic prediction model identifying patients with low paclitaxel clearance, based on the drug-metabolizing enzyme and transporter (DMET)-platform, capable of detecting 1,936 genetic variants in 225 metabolizing enzyme and drug transporter genes. Experimental Design: In 270 paclitaxel-treated patients, unbound plasma concentrations were determined and pharmacokinetic parameters were estimated from a previously developed population pharmacokinetic model (NONMEM). Patients were divided into a training-and validation set. Genetic variants determined by the DMET platform were selected from the training set to be included in the prediction model when they were associated with low paclitaxel clearance (1 SD below mean clearance) and subsequently tested in the validation set. Results: A genetic prediction model including 14 single-nucleotide polymorphisms (SNP) was developed on the training set. In the validation set, this model yielded a sensitivity of 95%, identifying most patients with low paclitaxel clearance correctly. The positive predictive value of the model was only 22%. The model remained associated with low clearance after multivariate analysis, correcting for age, gender, and hemoglobin levels at baseline (P = 0.02). Conclusions: In this first large-sized application of the DMET-platform for paclitaxel, we identified a 14 SNP model with high sensitivity to identify patients with low paclitaxel clearance. However, due to the low positive predictive value we conclude that genetic variability encoded in the DMET-chip alone does not sufficiently explain paclitaxel clearance.
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| 2. |
- de Graan, Anne-Joy M., et al.
(författare)
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CYP3A4*22 Genotype and Systemic Exposure Affect Paclitaxel-Induced Neurotoxicity
- 2013
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Ingår i: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 19:12, s. 3316-3324
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Paclitaxel is used for the treatment of several solid tumors and displays a high interindividual variation in exposure and toxicity. Neurotoxicity is one of the most prominent side effects of paclitaxel. This study explores potential predictive pharmacokinetic and pharmacogenetic determinants for the onset and severity of neurotoxicity. Experimental Design: In an exploratory cohort of patients (n = 261) treated with paclitaxel, neurotoxicity incidence, and severity, pharmacokinetic parameters and pharmacogenetic variants were determined. Paclitaxel plasma concentrations were measured by high-performance liquid chromatography or liquid chromatography/tandem mass spectrometry, and individual pharmacokinetic parameters were estimated from previously developed population pharmacokinetic models by nonlinear mixed effects modeling. Genetic variants of paclitaxel pharmacokinetics tested were CYP3A4*22, CYP2C8*3, CYP2C8*4, and ABCB1 3435 C>T. The association between CYP3A4*22 and neurotoxicity observed in the exploratory cohort was validated in an independent patient cohort (n = 239). Results: Exposure to paclitaxel ((log)AUC) was correlated with severity of neurotoxicity (P < 0.00001). Female CYP3A4*22 carriers were at increased risk of developing neurotoxicity (P = 0.043) in the exploratory cohort. CYP3A4*22 carrier status itself was not associated with pharmacokinetic parameters (CL, AUC, C-max, or T->0.05) of paclitaxel in males or females. Other genetic variants displayed no association with neurotoxicity. In the subsequent independent validation cohort, CYP3A4*22 carriers were at risk of developing grade 3 neurotoxicity (OR = 19.1; P = 0.001). Conclusions: Paclitaxel exposure showed a relationship with the severity of paclitaxel-induced neurotoxicity. In this study, female CYP3A4*22 carriers had increased risk of developing severe neurotoxicity during paclitaxel therapy. These observations may guide future individualization of paclitaxel treatment.
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| 3. |
- de Graan, Anne-Joy M., et al.
(författare)
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Influence of Polymorphic OATP1B-Type Carriers on the Disposition of Docetaxel
- 2012
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Ingår i: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 18:16, s. 4433-4440
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Docetaxel is extensively metabolized by CYP3A4 in the liver but mechanisms by which the drug is taken up into hepatocytes remain poorly understood. We hypothesized that (i) liver uptake of docetaxel is mediated by the polymorphic solute carriers OATP1B1 and OATP1B3 and (ii) inherited genetic defects in this process may impair systemic drug elimination.Experimental Design: Transport of docetaxel was studied in vitro using various cell lines stably transfected with OATP1B1*1A (wild-type), OATP1B1*5 [c.521T>C (V174A); rs4149056], OATP1B3, or the mouse transporter Oatp1b2. Docetaxel clearance was evaluated in wild-type and Oatp1b2-knockout mice as well as in two cohorts of patients with multiple variant transporter genotypes (n = 213).Results: Docetaxel was found to be a substrate for OATP1B1, OATP1B3, and Oatp1b2 but was not transported by OATP1B1*5. Deficiency of Oatp1b2 in mice was associated with an 18-fold decrease in docetaxel clearance (P = 0.0099), which was unrelated to changes in intrinsic metabolic capacity in mouse liver microsomes. In patients, however, none of the studied common reduced function variants in OATP1B1 or OATP1B3 were associated with docetaxel clearance (P > 0.05).Conclusions: The existence of at least two potentially redundant uptake transporters in the human liver with similar affinity for docetaxel supports the possibility that functional defects in both of these proteins may be required to confer substantially altered disposition phenotypes. In view of the established exposure-toxicity relationships for docetaxel, we suggest that caution is warranted if docetaxel has to be administered together with agents that potently inhibit both OATP1B1 and OATP1B3.
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| 4. |
- Elens, Laure, et al.
(författare)
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Genetic Predisposition to Poor Opioid Response in Preterm Infants : Impact of KCNJ6 and COMT Polymorphisms on Pain Relief after Endotracheal Intubation
- 2016
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Ingår i: Therapeutic Drug Monitoring. - 0163-4356 .- 1536-3694. ; 38:4, s. 525-533
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Tidskriftsartikel (refereegranskat)abstract
- Background: Single-nucleotide polymorphisms in genes involved in pain control might predispose to exaggerated sensitivity or difference in opioid analgesic effect. The relevance of the KCNJ6 -1250G>A (rs6517442, c.-1787G>A) and the catecholamine-O-methyltransferase (COMT) c.472G>A (rs4680, Val 158 Met) single-nucleotide polymorphisms were studied in preterm infants needing intubation and randomized to a premedication strategy including remifentanil (n 17) or morphine (n 17). Methods: Pain was scored with Astrid Lindgren and Lund Children's Hospital Pain Assessment Scale every 30 minutes for 6 hours. The pain relief provided by the opioids was compared between the different KCNJ6 and COMT genotypes. Results: Infants homozygous for the KCNJ6 -1250A allele had an increased duration after intubation to achieve a score indicating no pain compared with infants with the A/G or G/G genotypes (182 ± 30, 109 ± 29, and 60 ± 21 minutes, respectively; Logrank 7.5, P 0.006). Similarly, the duration was increased in individuals with the COMT Val/Val alleles compared with Val/Met and Met/Met (285 ± 37, 137 ± 25, and 63 ± 15 minutes, respectively; Logrank 14.4, P 0.0021). Cox proportional hazards analysis confirmed that the variation in both genes was independently associated with susceptibility to respond to therapy. Conclusion: We conclude that the KCNJ6 -1250A and COMT 158 Val alleles are predisposing preterm newborns to diminished opioid-induced pain relief.
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| 5. |
- Matic, Maja, et al.
(författare)
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Effect of UGT2B7-900G > A (-842G > A; rs7438135) on morphine glucuronidation in preterm newborns: results from a pilot cohort
- 2014
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Ingår i: Pharmacogenomics. - 1462-2416 .- 1744-8042. ; 15:12, s. 1589-1597
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Assess association between UGT2B7 polymorphism -900G>A (rs7438135, also known as -842G>A) with morphine kinetics in preterm newborns undergoing mechanical ventilation. Materials & methods: Thirty-four infants were enrolled in a randomized clinical trial and allocated to rapid sequence intubation with remifentanil (1 mu g/kg) or morphine (0.3 mg/kg). The latter group was included in our study. Results: Morphine plasma concentrations at 20 min post intubation were associated with postnatal age (p = 0.017) and UGT2B7 -900G>A (p = 0.036). UGT2B7 -900A allele carriers (n = 13) had lower morphine levels compared with UGT2B7 -900G/G patients (n = 2). Morphine-3-glucuronide and morphine-6-glucuronide plasma concentrations were only found to be associated with gestational and postnatal age. However, -900A allele carriers had a higher morphine-3-glucuronide: morphine metabolic ratio compared with patients genotyped as -900G/G (p = 0.005), as determined by linear regression. Conclusion: Our small pilot study illustrates that in addition to gestational and postnatal age, the UGT2B7 -900G>A polymorphism significantly alters morphine pharmacokinetics in preterm infants.
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