Pharmacogenetics is a rapidly developing field, especially in oncology. In the most ideal situation pharmacogenetics will allow oncologists to individualize therapy based on patients' individual germline genetic test results. This can help to improve efficacy, reduce toxicity and predict non-responders in a way that alternative therapy can be chosen or individual dose adjustments can be made. Multiple pathways have been studied extensively of which a brief review is presented here. Increased 5FU toxicity is associated with variations in the DPYD gene, TYMS gene and MTHFR gene. Furthermore variations in the UGT1A gene and the ABCB1 gene influence irinotecan metabolism and disposition. Other genetic changes result in reduced DNA repair capacity related to platinum efficacy or reduced cytochrome P450 2D6 activity related to tamoxifen efficacy. Despite the extensive number of pharmacogenetic studies and promising results, it is still unclear when and how pretreatment genetic screening should be implemented in oncology. Future prospective studies should focus on the effect of pharmacogenetics on patient outcome and combine this with cost effectiveness evaluations. Thus supplying us with predictive models helping in deciding when pretreatment genetic screening is useful.
The tyrosine kinase inhibitor sunitinib is used as first‐line therapy in patients with metastasized renal cell carcinoma (mRCC), given in fixed‐dose regimens despite its high variability in pharmacokinetics (PKs). Interindividual variability of drug exposure may be responsible for differences in response. Therefore, dosing strategies based on pharmacokinetic/pharmacodynamic (PK/PD) models may be useful to optimize treatment. Plasma concentrations of sunitinib, its active metabolite SU12662, and the soluble vascular endothelial growth factor receptors sVEGFR‐2 and sVEGFR‐3, were measured in 26 patients with mRCC within the EuroTARGET project and 21 patients with metastasized colorectal cancer (mCRC) from the C‐II‐005 study. Based on these observations, PK/PD models with potential influence of genetic predictors were developed and linked to time‐to‐event (TTE) models. Baseline sVEGFR‐2 levels were associated with clinical outcome in patients with mRCC, whereas active drug PKs seemed to be more predictive in patients with mCRC. The models provide the basis of PK/PD‐guided strategies for the individualization of anti‐angiogenic therapies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.