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
Wouden, C.H. van der; Guchelaar, H.J.; Swen, J.J. 2022
Transcriptome signature reversion (TSR) has been extensively proposed and used to discover new indications for existing drugs (i.e. drug repositioning, drug repurposing) for various cancer types.... Show moreTranscriptome signature reversion (TSR) has been extensively proposed and used to discover new indications for existing drugs (i.e. drug repositioning, drug repurposing) for various cancer types. TSR relies on the assumption that a drug that can revert gene expression changes induced by a disease back to original, i.e. healthy, levels is likely to be therapeutically active in treating the disease. Here, we aimed to validate the concept of TSR using the PRISM repurposing data set, which is-as of writing-the largest pharmacogenomic data set. The predictive utility of the TSR approach as it has currently been used appears to be much lower than previously reported and is completely nullified after the drug gene expression signatures are adjusted for the general anti-proliferative downstream effects of drug-induced decreased cell viability. Therefore, TSR mainly relies on generic anti-proliferative drug effects rather than on targeting cancer pathways specifically upregulated in tumor types. Show less
Background: Despite (neo) adjuvant chemotherapy with cisplatin, doxorubicin and methotrexate, some patients with primary osteosarcoma progress during first-line systemic treatment and have a poor... Show moreBackground: Despite (neo) adjuvant chemotherapy with cisplatin, doxorubicin and methotrexate, some patients with primary osteosarcoma progress during first-line systemic treatment and have a poor prognosis. In this study, we investigated whether patients with early disease progression (EDP), are characterized by a distinctive pharmacogenetic profile. Methods and Findings: Germline DNA from 287 Dutch high-grade osteosarcoma patients was genotyped using the DMET Plus array (containing 1,936 genetic markers in 231 drug metabolism and transporter genes). Associations between genetic variants and EDP were assessed using logistic regression models and associated variants (p < 0.05) were validated in independent cohorts of 146 (Spain and United Kingdom) and 28 patients (Australia). In the association analyses, EDP was significantly associated with an SLC7A8 locus and was independently validated (meta-analysis validation cohorts: OR 0.19 [0.06-0.55], p = 0.002). The functional relevance of the top hits was explored by immunohistochemistry staining and an in vitro transport models. SLC7A8 encodes for the L-type amino acid transporter 2 (LAT2). Transport assays in HEK293 cells overexpressing LAT2 showed that doxorubicin, but not cisplatin and methotrexate, is a substrate for LAT2 (p < 0.0001). Finally, SLC7A8 mRNA expression analysis and LAT2 immunohistochemistry of osteosarcoma tissue showed that the lack of LAT2 expression is a prognostic factor of poor prognosis and reduced overall survival in patients without metastases (p = 0.0099 and p = 0.14, resp.). Conclusion: This study identified a novel locus in SLC7A8 to be associated with EDP in osteosarcoma. Functional studies indicate LAT2-mediates uptake of doxorubicin, which could give new opportunities to personalize treatment of osteosarcoma patients. Show less
With, M. de; Knikman, J.; Schellens, J.H.M.; Gelderblom, H.; Cats, A.; Guchelaar, H.J.; ... ; Meulendijks, D. 2022
Aims Immunosuppressant and kidney function monitoring are crucial for kidney transplant recipient follow-up. Microsamples enable remote sampling and minimise patient burden as compared to... Show moreAims Immunosuppressant and kidney function monitoring are crucial for kidney transplant recipient follow-up. Microsamples enable remote sampling and minimise patient burden as compared to conventional venous sampling at the clinic. We developed a liquid chromatography-tandem mass spectrometry assay to quantify tacrolimus, mycophenolic acid (MPA), creatinine and iohexol in dried blood spot (DBS), and volumetric absorptive microsample (VAMS) samples. Methods The assay was successfully validated analytically for all analytes. Clinical validation was conducted by direct comparison of paired DBS, VAMS and venous reference samples from 25 kidney transplant recipients. Patients received iohexol 5-15 minutes before immunosuppressant intake and were sampled 0, 1, 2 and 3 hours thereafter, enabling tacrolimus and MPA area under the concentration-time curve (AUC) and creatinine-based and iohexol-based glomerular filtration rate (GFR) estimation. Method agreement was evaluated using Passing-Bablok regression, Bland-Altman analysis and the percentages of values within 15-30% of the reference (P-15-P-30) with a P-20 acceptance threshold of 80%. Results For DBS samples, method agreement was excellent for tacrolimus trough concentrations (n = 25, P-15 = 92.0%) and AUCs (n = 25; P-20 = 95.8%) and adequate for creatinine-based GFR trend monitoring (n = 25; P-20 = 80%). DBS-based MPA AUC assessment showed suboptimal agreement (n = 16; P-20 = 68.8%), but was considered acceptable given its P-30 of 100%. The assay performed inadequately for DBS-based iohexol GFR determination (n = 24; P-20 = 75%). The VAMS technique generally showed inferior performance, but can be considered for certain situations. Conclusion The assay was successfully validated for tacrolimus, MPA and creatinine quantification in DBS samples, enabling simultaneous remote kidney function trend monitoring and immunosuppressant therapeutic drug monitoring in kidney transplant recipients. Show less
The use of monoclonal antibodies (mAbs) in the clinic has successfully expanded to treatment of cancer, viral infections, inflammations, and other indications. However, some of the classes of mAbs... Show moreThe use of monoclonal antibodies (mAbs) in the clinic has successfully expanded to treatment of cancer, viral infections, inflammations, and other indications. However, some of the classes of mAbs that are used in the clinic show the formation of anti-drug antibodies (ADAs) leading to loss of efficacy. This review describes ADA formation for the various mAbs, and its clinical effect. Lastly, this review considers the use of HLA-haplotypes as biomarkers to predict vulnerability of patients sensitive to formation of ADAs. Show less
Stoep, M.Y.E.C. van der; Oostenbrink, L.V.E.; Bredius, R.G.M.; Moes, D.J.A.R.; Guchelaar, H.J.; Zwaveling, J.; Lankester, A.C. 2022
Allogeneic hematopoietic stem cell transplantation (HSCT) is an established curative treatment that has significantly improved clinical outcome of pediatric patients with malignant and non... Show moreAllogeneic hematopoietic stem cell transplantation (HSCT) is an established curative treatment that has significantly improved clinical outcome of pediatric patients with malignant and non-malignant disorders. This is partly because of the use of safer and more effective combinations of chemo- and serotherapy prior to HSCT. Still, complications due to the toxicity of these conditioning regimens remains a major cause of transplant-related mortality (TRM). One of the most difficult challenges to further improve HSCT outcome is reducing toxicity while maintaining efficacy. The use of personalized dosing of the various components of the conditioning regimen by means of therapeutic drug monitoring (TDM) has been the topic of interest in the last decade. TDM could play an important role, especially in children who tend to show greater pharmacokinetic variability. However, TDM should only be performed when it has clear added value to improve clinical outcome or reduce toxicity. In this review, we provide an overview of the available evidence for the relationship between pharmacokinetic parameters and clinical outcome or toxicities of the most commonly used conditioning agents in pediatric HSCT. Show less
Introduction: Suboptimal self-management of inhaled corticosteroids (ICS) in asthma patients is frequently observed in clinical practice and associated with poor asthma control. Driving factors for... Show moreIntroduction: Suboptimal self-management of inhaled corticosteroids (ICS) in asthma patients is frequently observed in clinical practice and associated with poor asthma control. Driving factors for suboptimal self-management are complex and consist of a range of behavioral barriers (cognitive, affective and practical) with a considerable inter-individual variability. Identification of individual barriers facilitates the use of corresponding behavior change techniques and tailored care to improve asthma treatment outcomes.Objective: This study describes the development and validation of the 'Respiratory Adherence Care Enhancer' (RACE) questionnaire to identify individual barriers to self-management of ICS therapy in asthma patients.Methods: The development included: 1) an inventory of self-management barriers based on a literature review, 2) expert assessment on relevance and completeness of this set, linking these barriers to behavioral domains of the Theoretical Domains Framework (TDF) and 3) the formulation of corresponding questions assessing each of the barriers. A cross-sectional study was performed for validation. Primary care asthma patients were invited to fill out the RACE-questionnaire prior to a semi-structured telephonic interview as golden standard. Barriers detected from the questionnaire were compared to those mentioned in the interview.Results: The developed questionnaire is made up of 6 TDF-domains, covering 10 self-management barriers with 23 questions. For the validation 64 patients completed the questionnaire, of whom 61 patients were interviewed. Cronbach's alpha for the consistency of questions within the barriers ranged from 0.58 to 0.90. Optimal cut-off values for the presence of barriers were determined at a specificity between 67 and 92% with a sensitivity between 41 and 83%. Significant Areas Under the Receiver Operating Curves values were observed for 9 barriers with values between 0.69 and 0.86 (p-value <0.05), except for 'Knowledge of ICS medication' with an insignificant value of 0.53.Conclusion: The RACE-questionnaire yields adequate psychometric characteristics to identify individual barriers to self-management of ICS therapy in asthma patients, facilitating tailored care. Show less
Brouwer, J.M.J.L.; Nijenhuis, M.; Soree, B.; Guchelaar, H.J.; Swen, J.J.; Schaik, R.H.N. van; ... ; Mulder, H. 2021
The Dutch Pharmacogenetics Working Group (DPWG) guideline presented here, presents the gene-drug interaction between the genes CYP2C19 and CYP2D6 and antidepressants of the selective serotonin... Show moreThe Dutch Pharmacogenetics Working Group (DPWG) guideline presented here, presents the gene-drug interaction between the genes CYP2C19 and CYP2D6 and antidepressants of the selective serotonin reuptake inhibitor type (SSRIs). Both genes' genotypes are translated into predicted normal metabolizer (NM), intermediate metabolizer (IM), poor metabolizer (PM), or ultra-rapid metabolizer (UM). Evidence-based dose recommendations were obtained, based on a structured analysis of published literature. In CYP2C19 PM patients, escitalopram dose should not exceed 50% of the normal maximum dose. In CYP2C19 IM patients, this is 75% of the normal maximum dose. Escitalopram should be avoided in UM patients. In CYP2C19 PM patients, citalopram dose should not exceed 50% of the normal maximum dose. In CYP2C19 IM patients, this is 70% (65-75%) of the normal maximum dose. In contrast to escitalopram, no action is needed for CYP2C19 UM patients. In CYP2C19 PM patients, sertraline dose should not exceed 37.5% of the normal maximum dose. No action is needed for CYP2C19 IM and UM patients. In CYP2D6 UM patients, paroxetine should be avoided. No action is needed for CYP2D6 PM and IM patients. In addition, no action is needed for the other gene-drug combinations. Clinical effects (increase in adverse events or decrease in efficacy) were lacking for these other gene-drug combinations. DPWG classifies CYP2C19 genotyping before the start of escitalopram, citalopram, and sertraline, and CYP2D6 genotyping before the start of paroxetine as "potentially beneficial" for toxicity/effectivity predictions. This indicates that genotyping prior to treatment can be considered on an individual patient basis. 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
Matic, M.; Nijenhuis, M.; Soree, B.; Boer-Veger, N.J. de; Buunk, A.M.; Houwink, E.J.F.; ... ; Schaik, R.H.N. van 2021
The current Dutch Pharmacogenetics Working Group (DPWG) guideline, describes the gene-drug interaction between CYP2D6 and the opioids codeine, tramadol and oxycodone. CYP2D6 genotype is translated... Show moreThe current Dutch Pharmacogenetics Working Group (DPWG) guideline, describes the gene-drug interaction between CYP2D6 and the opioids codeine, tramadol and oxycodone. CYP2D6 genotype is translated into normal metaboliser (NM), intermediate metaboliser (IM), poor metaboliser (PM) or ultra-rapid metaboliser (UM). Codeine is contraindicated in UM adults if doses >20 mg every 6 h (q6h), in children >= 12 years if doses >10 mg q6h, or with additional risk factors. In PMs, an alternative analgesic should be given which is not or to a lesser extent metabolised by CYP2D6 (not tramadol). In IMs with insufficient analgesia, a higher dose or alternative analgesic should be given. For tramadol, the recommendations for IMs and PMs are the same as the recommendation for codeine and IMs. UMs should receive an alternative drug not or to a lesser extent metabolised by CYP2D6 or the dose should be decreased to 40% of the commonly prescribed dose. Due to the absence of effect on clinical outcomes of oxycodone in PMs, IMs and UMs no action is required. DPWG classifies CYP2D6 genotyping for codeine "beneficial" and recommends testing prior to, or shortly after initiation of treatment in case of higher doses or additional risk factors. CYP2D6 genotyping is classified as "potentially beneficial" for tramadol and can be considered on an individual patient basis. Show less
Daele, R. van; Debaveye, Y.; Vos, R.; Bleyenbergh, P. van; Bruggemann, R.J.; Dreesen, E.; ... ; Spriet, I. 2021
Background Isavuconazole is a triazole antifungal drug, approved for the treatment of invasive aspergillosis and mucormycosis. Isavuconazole is metabolised by CYP3A4 and CYP3A5, and it has been... Show moreBackground Isavuconazole is a triazole antifungal drug, approved for the treatment of invasive aspergillosis and mucormycosis. Isavuconazole is metabolised by CYP3A4 and CYP3A5, and it has been shown that the CYP3A inducer rifampin reduces isavuconazole exposure. By extrapolation, the concomitant use of isavuconazole with moderate and strong CYP450 inducers is contraindicated, although it is known that some CYP450 inducers are less potent in comparison with rifampin.Objectives We aim to document exposure to isavuconazole in patients concomitantly treated with a CYP450 inducer that is less potent compared to rifampin. Moreover, although it is well known that CYP3A enzymes are important for the metabolism of isavuconazole, this induction effect has never been studied in combination with the patient's CYP3A genotype.Patients We report three patients treated with both isavuconazole and a CYP3A inducer that is less potent compared to rifampin (rifabutin or phenobarbital), in whom we determined isavuconazole concentrations.Results These cases suggest that the CYP3A4/5 genotype is an important determinant for isavuconazole exposure and that it might also influence the CYP450 induction interaction.Conclusions CYP3A inducers that are less potent compared to rifampin, may be combined with isavuconazole in patients with loss of CYP3A5 activity (CYP3A5*3/*3). Therapeutic drug monitoring is recommended during this combination. However, low-isavuconazole exposure was observed in the extensive metaboliser with CYP3A4*1/*1 and CYP3A5*1/*3 alleles. Show less
Motivation: When phase III clinical drug trials fail their endpoint, enormous resources are wasted. Moreover, even if a clinical trial demonstrates a significant benefit, the observed effects are... Show moreMotivation: When phase III clinical drug trials fail their endpoint, enormous resources are wasted. Moreover, even if a clinical trial demonstrates a significant benefit, the observed effects are often small and may not outweigh the side effects of the drug. Therefore, there is a great clinical need for methods to identify genetic markers that can identify subgroups of patients which are likely to benefit from treatment as this may (i) rescue failed clinical trials and/or (ii) identify subgroups of patients which benefit more than the population as a whole. When single genetic biomarkers cannot be found, machine learning approaches that find multivariate signatures are required. For single nucleotide polymorphism (SNP) profiles, this is extremely challenging owing to the high dimensionality of the data. Here, we introduce RAINFOREST (tReAtment benefIt prediction using raNdom FOREST), which can predict treatment benefit from patient SNP profiles obtained in a clinical trial setting.Results: We demonstrate the performance of RAINFOREST on the CAIRO2 dataset, a phase III clinical trial which tested the addition of cetuximab treatment for metastatic colorectal cancer and concluded there was no benefit. However, we find that RAINFOREST is able to identify a subgroup comprising 27.7% of the patients that do benefit, with a hazard ratio of 0.69 (P = 0.04) in favor of cetuximab. The method is not specific to colorectal cancer and could aid in reanalysis of clinical trial data and provide a more personalized approach to cancer treatment, also when there is no clear link between a single variant and treatment benefit. 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
Multiple pharmacogenetic studies investigated the effectiveness of methotrexate. However, due to the use of nonvalidated outcomes, lack of validation or conflicting results it remains unclear if... Show moreMultiple pharmacogenetic studies investigated the effectiveness of methotrexate. However, due to the use of nonvalidated outcomes, lack of validation or conflicting results it remains unclear if genetic markers can help to predict response to MTX treatment. Therefore, a systematic review was performed. PubMed was searched for articles reporting potential pharmacogenetic biomarkers associated (p < 0.05) with MTX efficacy using the validated endpoints DAS(28), EULAR, or ACR response criteria. The PICO method was used for study selection, and PRISMA guidelines to prepare the report. Thirty-five studies met the inclusion criteria, providing 39 potential genetic biomarkers in 19 genes. After Bonferroni correction, six genetic biomarkers were associated with the efficacy of MTX: ATIC rs7563206; SLC19A1 rs1051266; DHFR rs836788; TYMS rs2244500, rs2847153, and rs3786362 in at least one study. Only SLC19A1 rs1051266 was replicated in an independent cohort and promising for predicting methotrexate efficacy. Show less
