DPYD-guided dosing has improved the safety of fluoropyrimidine-based chemotherapy in recent years. However, severe toxicity remains in similar to 23% of patients not carrying DPYD variant alleles... Show moreDPYD-guided dosing has improved the safety of fluoropyrimidine-based chemotherapy in recent years. However, severe toxicity remains in similar to 23% of patients not carrying DPYD variant alleles treated with capecitabine. Therefore, we developed a predictive model based on patient-related and treatment-related factors aimed at estimating the risk of developing severe capecitabine-related toxicity. The nomogram was developed using data from two large clinical trials (NCT00838370 and NCT02324452). Patients with cancer carrying a DPYD variant allele (DPYD*2A, c.1236G>A, c.2846A>T, and c.1679T>G) were excluded. Univariable and multivariable logistic regression using predetermined predictors based on previous findings, including age, sex, body surface area, type of treatment regimen, and creatinine levels were used to develop the nomogram. The developed model was internally validated using bootstrap resampling and cross-validation. This model was not externally or clinically validated. A total of 2,147 DPYD wild-type patients with cancer treated with capecitabine-based chemotherapy regimens were included of which complete data of 1,745 patients were available and used for the development of the nomogram. Univariable and multivariable logistic regression showed that age, sex, and type of treatment regimen were strong predictors of severe capecitabine-related toxicity in DPYD wild-type patients. Internal validation demonstrated a concordance index of 0.68 which indicates a good discriminative ability for prediction of severe capecitabine-related toxicity. The developed nomogram includes readily available parameters and may be a helpful tool for clinicians to assess the risk of developing severe capecitabine-related toxicity in patients without known risk DPYD variant alleles treated with capecitabine-based anticancer regimens. Show less
Purpose More medication-related issues are seen with the growing demand for bariatric surgery, because of possible altered pharmacokinetics after surgery. Collaboration with a pharmacist could... Show morePurpose More medication-related issues are seen with the growing demand for bariatric surgery, because of possible altered pharmacokinetics after surgery. Collaboration with a pharmacist could improve the short- and long-term safety and efficacy of pharmacotherapy in patients undergoing bariatric surgery. The aim of this study was to evaluate the impact of a structured medication review to identify medication-related risks before bariatric surgery.Materials and Methods The impact on pharmacy-led interventions of introducing a structured medication review was evaluated in a historically controlled study. In the retrospective part, we evaluated patient characteristics, medication use, and number of pre-surgery consultations with a pharmacist before the introduction of medication reviews. A flowchart was developed to detect the use of medicines with risks associated with bariatric surgery. In the prospective part, we evaluated pharmacy-led interventions after the introduction of structured medication reviews using the flowchart. Outcome effectiveness was measured through the number of pre-surgery pharmacy-led interventions.Results Before using the flowchart for screening on risk medicines, 40 (2.6%) pharmacy-led interventions were identified in 1536 patients. In the prospective group, 195 patients were included and 88 (45%) interventions were identified (p < 0.001).Conclusion A structured medication review before bariatric surgery significantly increased the number of pharmacy-led interventions in bariatric surgery patients. This procedure will shift interventions to pre-surgery instead of post-surgery, contributing to the optimization of pharmacotherapy at an early stage. Show less
Heine, R. ter; Heuvel, M.M. van den; Piet, B.; Deenen, M.J.; Wekken, A.J. van der; Hendriks, L.E.L.; ... ; Rouw, N. de 2023
BackgroundExpensive novel anticancer drugs put a serious strain on healthcare budgets, and the associated drug expenses limit access to life-saving treatments worldwide.ObjectiveWe aimed to develop... Show moreBackgroundExpensive novel anticancer drugs put a serious strain on healthcare budgets, and the associated drug expenses limit access to life-saving treatments worldwide.ObjectiveWe aimed to develop alternative dosing regimens to reduce drug expenses.MethodsWe developed alternative dosing regimens for the following monoclonal antibodies used for the treatment of lung cancer: amivantamab, atezolizumab, bevacizumab, durvalumab, ipilimumab, nivolumab, pembrolizumab, and ramucirumab; and for the antibody-drug conjugate trastuzumab deruxtecan. The alternative dosing regimens were developed by means of modeling and simulation based on the population pharmacokinetic models developed by the license holders. They were based on weight bands and the administration of complete vials to limit drug wastage. The resulting dosing regimens were developed to comply with criteria used by regulatory authorities for in silico dose development.ResultsWe found that alternative dosing regimens could result in cost savings that range from 11 to 28%, and lead to equivalent pharmacokinetic exposure with no relevant increases in variability in exposure.ConclusionsDosing regimens based on weight bands and the use of complete vials to reduce drug wastage result in less expenses while maintaining equivalent exposure. The level of evidence of our proposal is the same as accepted by regulatory authorities for the approval of alternative dosing regimens of other monoclonal antibodies in oncology. The proposed alternative dosing regimens can, therefore, be directly implemented in clinical practice. Show less
Patients with chronic kidney disease (CKD) stage 3-5 are polypharmacy patients. Many of these drugs are metabolized by cytochrome P450 (CYP450) and CYP450. Genetic polymorphism is well known to... Show morePatients with chronic kidney disease (CKD) stage 3-5 are polypharmacy patients. Many of these drugs are metabolized by cytochrome P450 (CYP450) and CYP450. Genetic polymorphism is well known to result in altered drug metabolism capacity. This study determined the added value of pharmacogenetic testing to the routine medication evaluation in polypharmacy patients with CKD. In adult outpatient polypharmacy patients with CKD3-5 disease, a pharmacogenetic profile was determined. Then, automated medication surveillance for gene-drug interactions was performed based on the pharmacogenetic profile and the patients' current prescriptions. Of all identified gene-drug interactions, the hospital pharmacist and the treating nephrologist together assessed clinical relevance and necessity of a pharmacotherapeutic intervention. The primary endpoint of the study was the total number of applied pharmacotherapeutic interventions based on a relevant gene-drug interaction. A total of 61 patients were enrolled in the study. Medication surveillance resulted in a total of 66 gene-drug interactions, of which 26 (39%) were considered clinically relevant. This resulted in 26 applied pharmacotherapeutic interventions in 20 patients. Systematic pharmacogenetic testing enables pharmacotherapeutic interventions based on relevant gene-drug interactions. This study showed that pharmacogenetic testing adds to routine medication evaluation and could lead to optimized pharmacotherapy in CKD patients. Show less
The Dutch Pharmacogenetics Working Group (DPWG) aims to facilitate PGx implementation by developing evidence-based pharmacogenetics guidelines to optimize pharmacotherapy. This guideline describes... Show moreThe Dutch Pharmacogenetics Working Group (DPWG) aims to facilitate PGx implementation by developing evidence-based pharmacogenetics guidelines to optimize pharmacotherapy. This guideline describes the starting dose optimization of the anti-cancer drug irinotecan to decrease the risk of severe toxicity, such as (febrile) neutropenia or diarrhoea. Uridine diphosphate glucuronosyl transferase 1A1 (UGT1A1 encoded by the UGT1A1 gene) enzyme deficiency increases risk of irinotecan-induced toxicity. Gene variants leading to UGT1A1 enzyme deficiency (e.g. UGT1A1*6, *28 and *37) can be used to optimize an individual's starting dose thereby preventing carriers from toxicity. Homozygous or compound heterozygous carriers of these allele variants are defined as UGT1A1 poor metabolisers (PM). DPWG recommends a 70% starting dose in PM patients and no dose reduction in IM patients who start treatment with irinotecan. Based on the DPWG clinical implication score, UGT1A1 genotyping is considered "essential", indicating that UGT1A1 testing must be performed prior to initiating irinotecan treatment. Show less
Aim: To determine the safety, feasibility, pharmacokinetics, and cost of UGT1A1 genotype-guided dosing of irinotecan.Patients and methods: In this prospective, multicentre, non-randomised study,... Show moreAim: To determine the safety, feasibility, pharmacokinetics, and cost of UGT1A1 genotype-guided dosing of irinotecan.Patients and methods: In this prospective, multicentre, non-randomised study, patients intended for treatment with irinotecan were pre-therapeutically genotyped for UGT1A1*28 and UGT1A1)93. Homozygous variant carriers (UGT1A1 poor metabolisers; PMs) received an initial 30% dose reduction. The primary endpoint was incidence of febrile neutropenia in the first two cycles of treatment. Toxicity in UGT1A1 PMs was compared to a historical cohort of UGT1A1 PMs treated with full dose therapy, and to UGT1A1 non-PMs treated with full dose therapy in the current study. Secondary endpoints were pharmacokinetics, feasi- bility, and costs.Results: Of the 350 evaluable patients, 31 (8.9%) patients were UGT1A1 PM and received a median 30% dose reduction. The incidence of febrile neutropenia in this group was 6.5% compared to 24% in historical UGT1A1 PMs (P = 0.04) and was comparable to the incidence in UGT1A1 non-PMs treated with full dose therapy. Systemic exposure of SN-38 of reduced dosing in UGT1A1 PMs was still slightly higher compared to a standard-dosed irinotecan patient cohort (difference: thorn 32%). Cost analysis showed that genotype-guided dosing was cost-saving with a cost reduction of V183 per patient.Conclusion: UGT1A1 genotype-guided dosing significantly reduces the incidence of febrile neutropenia in UGT1A1 PM patients treated with irinotecan, results in a therapeutically effec- tive systemic drug exposure, and is cost-saving. Therefore, UGT1A1 genotype-guided dosing of irinotecan should be considered standard of care in order to improve individual patient safety. (C) 2022 The Authors. Published by Elsevier Ltd. Show less
Lee, M. van der; Allard, W.G.; Vossen, R.H.A.M.; Baak-Pablo, R.F.; Menafra, R.; Deiman, B.A.L.M.; ... ; Anvar, S.Y. 2021
Pharmacogenomics is a key component of personalized medicine that promises safer and more effective drug treatment by individualizing drug choice and dose based on genetic profiles. In clinical... Show morePharmacogenomics is a key component of personalized medicine that promises safer and more effective drug treatment by individualizing drug choice and dose based on genetic profiles. In clinical practice, genetic biomarkers are used to categorize patients into *-alleles to predict CYP450 enzyme activity and adjust drug dosages accordingly. However, this approach leaves a large part of variability in drug response unexplained. Here, we present a proof-of-concept approach that uses continuous-scale (instead of categorical) assignments to predict enzyme activity. We used full CYP2D6 gene sequences obtained with long-read amplicon-based sequencing and cytochrome P450 (CYP) 2D6-mediated tamoxifen metabolism data from a prospective study of 561 patients with breast cancer to train a neural network. The model explained 79% of interindividual variability in CYP2D6 activity compared to 54% with the conventional *-allele approach, assigned enzyme activities to known alleles with previously reported effects, and predicted the activity of previously uncharacterized combinations of variants. The results were replicated in an independent cohort of tamoxifen-treated patients (model R-2 adjusted = 0.66 versus *-allele R-2 adjusted = 0.35) and a cohort of patients treated with the CYP2D6 substrate venlafaxine (model R2 adjusted = 0.64 versus *-allele R-2 adjusted = 0.55). Human embryonic kidney cells were used to confirm the effect of five genetic variants on metabolism of the CYP2D6 substrate bufuralol in vitro. These results demonstrate the advantage of a continuous scale and a completely phased genotype for prediction of CYP2D6 enzyme activity and could potentially enable more accurate prediction of individual drug response. Show less
Hulshof, E.C.; Deenen, M.J.; Guchelaar, H.J.; Gelderblom, H. 2020
Background: Pre-therapeutic UGT1A1 genotyping is not yet routinely performed in most hospitals in patients starting irinotecan chemotherapy. The aim of this position paper was to evaluate the... Show moreBackground: Pre-therapeutic UGT1A1 genotyping is not yet routinely performed in most hospitals in patients starting irinotecan chemotherapy. The aim of this position paper was to evaluate the available evidence and to assess the potential value of genotyping of UGT1A1*28 and UGT1A1*6 in patients before starting treatment with irinotecan to reduce the risk of severe toxicity.Methods: The literature was selected and assessed based on five pre-specified criteria: 1) the level of evidence for associations between UGT1A1 polymorphisms and irinotecan-induced severe toxicity, 2) clinical validity and utility of pre-therapeutic genotyping of UGT1A1, 3) safety and tolerability of irinotecan in carriers of UGT1A1 polymorphisms, 4) availability of specific dose recommendations for irinotecan in carriers of UGT1A1 polymorphisms, 5) evidence of cost benefits of pre-therapeutic genotyping of UGT1A1.Results: On all five criteria, study results were favourable for pre-therapeutic genotyping of UGT1A1. A high level of evidence (level I) was found for a higher incidence of irinotecan-induced severe toxicity in homozygous carriers of UGT1A1*28 or UGT1A1*6. The clinical validity and utility of this genetic test proved to be acceptable. Dose-finding studies showed a lower maximum tolerated dose in homozygous variant allele carriers, and most of the drug labels and guidelines recommend a dose reduction of 25-30% in these patients. In addition, pre-therapeutic genotyping of UGT1A1 is likely to save costs.Conclusion: Pre-therapeutic genotyping of UGT1A1 in patients initiating treatment with irinotecan improves patient safety, is likely to be cost-saving, and should, therefore, become standard of care. (C) 2020 The Author(s). Published by Elsevier Ltd. Show less
Background The introduction of cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC) with either oxaliplatin or mitomycin C for patients with colorectal... Show moreBackground The introduction of cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC) with either oxaliplatin or mitomycin C for patients with colorectal peritoneal metastasis (CPM) has resulted in a major increase in overall survival. Nonetheless, despite critical patient selection, the majority of patients will develop recurrent disease within one year following CRS + HIPEC. Therefore, improvement of patient and treatment selection is needed and may be achieved by the incorporation of genetic biomarkers. This systematic review aims to provide an overview of genetic biomarkers in the DNA repair pathway that are potentially predictive for treatment outcome of patients with colorectal peritoneal metastases treated with CRS + HIPEC with oxaliplatin or mitomycin C. Methods A systematic review was conducted according to the PRISMA guidelines. Given the limited number of genetic association studies of intraperitoneal mitomycin C and oxaliplatin in patients with CPM, we expanded the review and extrapolated the data from biomarker studies conducted in colorectal cancer patients treated with systemic mitomycin C- and oxaliplatin-based chemotherapy. Results In total, 43 papers were included in this review. No study reported potential pharmacogenomic biomarkers in patients with colorectal cancer undergoing mitomycin C-based chemotherapy. For oxaliplatin-based chemotherapy, a total of 26 genetic biomarkers within 14 genes were identified that were signi?cantly associated with treatment outcome. The most promising genetic biomarkers wereERCC1rs11615,XPCrs1043953,XPDrs13181,XPGrs17655,MNATrs3783819/rs973063/rs4151330, MMR status, ATM protein expression,HIC1tandem repeat D17S5, andPIN1rs2233678. Conclusion Several genetic biomarkers have proven predictive value for the treatment outcome of systemically administered oxaliplatin. By extrapolation, these genetic biomarkers may also be predictive for the efficacy of intraperitoneal oxaliplatin. This should be the subject of further investigation. Show less
Introduction: Mitomycin C (MMC) is commonly used in patients with colorectal peritoneal metastases (CPM) treated with cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy (CRS +... Show moreIntroduction: Mitomycin C (MMC) is commonly used in patients with colorectal peritoneal metastases (CPM) treated with cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy (CRS + HIPEC). MMC requires metabolic activation prior to exert its cytotoxic effect of which the main activating enzymes are NQO1 and POR. However, not all patients are able to activate MMC for example due to polymorphisms in the genes encoding these enzymes. The aim of this study was to investigate the association of NQO1*2, NQO1*3, and POR*28 with the efficacy of CRS + HIPEC with MMC in patients with CPM.Method: A retrospective follow-up design was used to study genetic association in patients with histologically proven CPM treated with CRS + HIPEC with MMC with respect to peritoneal recurrence rate after 3 months (primary endpoint), after 6 months, disease-free survival and overall survival. Genetic polymorphisms NQO1*2, NQO1*3, and POR*28 were tested for association.Results: A total of 253 patients were included. In NQO1*3 carriers the peritoneal recurrence rate 3 and 6 months after HIPEC was significantly higher than in wild type patients, respectively 30.0% vs 3.8% (p = 0.009) and 40.0% vs 12.1% (p = 0.031). In line with these results, NQO1*3 was associated with a shorter disease-free survival (HR 2.04, 95% CI [1.03-4.03]). There was no significant association with overall survival (HR 1.42, 95% CI [0.66-3.07]).Conclusion: Carriership of the NQO1*3 allele is associated with worse peritoneal recurrence rate and disease-free survival. These results suggest that individualization of patients treated with CRS + HIPEC based upon pharmacogenetics may be beneficial. (C) 2020 Elsevier Ltd, BASO similar to The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved. Show less
Background Electrostatic pressurized intraperitoneal aerosol chemotherapy (ePIPAC) is a palliative treatment for unresectable peritoneal metastases from various primary cancers. However, little is... Show moreBackground Electrostatic pressurized intraperitoneal aerosol chemotherapy (ePIPAC) is a palliative treatment for unresectable peritoneal metastases from various primary cancers. However, little is known about the systemic pharmacokinetics of oxaliplatin after ePIPAC. Methods Twenty patients with unresectable colorectal peritoneal metastases were treated with repetitive ePIPAC monotherapy with oxaliplatin (92 mg/m(2)) and a simultaneous intravenous bolus of leucovorin (20 mg/m(2)) and 5-fluorouracil (400 mg/m(2)). Samples were collected during each ePIPAC: whole blood att = 0,t = 5,t = 10,t = 20,t = 30,t = 60,t = 120,t = 240,t = 360 andt = 1080 min for plasma and plasma ultrafiltrate concentrations; urine att = 0,t = 1,t = 3,t = 5 andt = 7 days. Samples were analyzed using atomic absorption spectrometry. Pharmacokinetics were analyzed using nonlinear mixed-effects modeling. Results Four patients received one ePIPAC, three patients received two ePIPAC, and thirteen patients received >= 3 ePIPAC. The population pharmacokinetic models adequately described the pharmacokinetics of oxaliplatin after ePIPAC. The plasma ultrafiltrateC(max)of oxaliplatin reached 1.36-1.90 mu g/mL after 30 min with an AUC(0-24 h)of 9.6-11.7 mu g/mL * h. The plasmaC(max)reached 2.67-3.28 mu g/mL after 90 min with an AUC(0-24 h)of 49.0-59.5 mu g/mL * h. The absorption rate constant (Ka) was 1.13/h. Urine concentrations of oxaliplatin rapidly decreased to less than 3.60 mu g/mL in 90% of the samples at day 7. Discussion Systemic exposure to oxaliplatin after ePIPAC seemed comparable to that after systemic chemotherapy, as described in other literature. Since this is an indirect comparison, future research should focus on the direct comparison between the systemic exposure to oxaliplatin after ePIPAC and after systemic chemotherapy. Show less
Jacobs, B.A.W.; Deenen, M.J.; Joerger, M.; Rosing, H.; Vries, N. de; Meulendijks, D.; ... ; Huitema, A.D.R. 2019
Capecitabine is an oral prodrug of the anticancer drug 5-fluorouracil (5-FU). The primary aim of this study was to develop a pharmacokinetic model for capecitabine and its metabolites, 5 '-deoxy-5... Show moreCapecitabine is an oral prodrug of the anticancer drug 5-fluorouracil (5-FU). The primary aim of this study was to develop a pharmacokinetic model for capecitabine and its metabolites, 5 '-deoxy-5-fluorocytidine (dFCR), 5 '-deoxy-5-fluorouridine (dFUR), 5-FU, and fluoro-beta-alanine (FBAL) using data from a heterogeneous population of cancer patients (n = 237) who participated in seven clinical studies. A four-transit model adequately described capecitabine absorption. Capecitabine, dFCR, and FBAL pharmacokinetics were well described by two-compartment models, and dFUR and 5-FU were subject to flip-flop pharmacokinetics. Partial and total gastrectomy were associated with a significantly faster capecitabine absorption resulting in higher capecitabine and metabolite peak concentrations. Patients who were heterozygous polymorphic for a genetic mutation encoding dihydropyrimidine dehydrogenase, the DPYD*2A mutation, demonstrated a 21.5% (relative standard error 11.2%) reduction in 5-FU elimination. This comprehensive population model gives an extensive overview of capecitabine and metabolite pharmacokinetics in a large and heterogeneous population of cancer patients. Show less
Metoprolol is among the most frequently prescribed beta-blockers for the treatment of various cardiovascular diseases. Genetic polymorphism within CYP2D6 has been shown to affect the rate of... Show moreMetoprolol is among the most frequently prescribed beta-blockers for the treatment of various cardiovascular diseases. Genetic polymorphism within CYP2D6 has been shown to affect the rate of metabolism of metoprolol. Whether metoprolol dose adjustments are indicated in CYP2D6 poor metabolizers (PMs) has thus far not well been studied. The aim of this study was to determine the effect of the CYP2D6 genotype on the metoprolol maintenance dose in a chronic Dutch patient population. Patients were included if they were treated with metoprolol and in whom CYP2D6 genotype status was known. Patient and treatment characteristics were obtained retrospectively from the electronic healthcare records. Metoprolol maintenance dose was the primary endpoint and was defined as the last known dose that the patients had been treated with. Genotype data were categorized into four phenotypes, that is, PMs, intermediate metabolizers, extensive metabolizers, and ultra-rapid metabolizers (UMs). The endpoints were analyzed as PM versus non-PM. A total of 105 patients were included. The mean +/- SD maintenance dose in PMs (n = 12) was significantly lower compared with non-PMs (n = 93), that is, 48 +/- 20 versus 84 +/- 53 mg, respectively (P = 0.019). No association of the CYP2D6 genotype with the incidence of side effects was observed, although there was a trend for increased risk of drowsiness (P = 0.053). The results of this study show that the CYP2D6 genotype is associated with the maintenance dose of metoprolol. Patients with the CYP2D6 PM phenotype may benefit from a lower metoprolol starting dose, followed by further dose titration to provide patient-tailored therapy and thereby increase the effectiveness of treatment. Show less
Bury, D.; Heine, R. ter; Garde, E.M.W. van de; Nijziel, M.R.; Grouls, R.J.; Deenen, M.J. 2019
