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Dive into the research topics where Gw Frederix is active.

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Featured researches published by Gw Frederix.


Trends in Molecular Medicine | 2018

Is It Our Duty To Hunt for Pathogenic Mutations

Roel H.P. Wouters; Rhodé M. Bijlsma; Gw Frederix; Margreet G. E. M. Ausems; Johannes J. M. van Delden; Emile E. Voest; Annelien L. Bredenoord

Should professionals systematically screen whole-genome sequencing (WGS) data to check for life-threatening mutations? Alternatively, should genome analysis focus on the primary reason for testing - that is, aiming to achieve precision medicine? We present an ethical review of the arguments and compare the act of searching for mutations with disclosing mutations that are discovered incidentally.


Lancet Oncology | 2018

DPYD genotype-guided dose individualisation of fluoropyrimidine therapy in patients with cancer: a prospective safety analysis

Linda M. Henricks; Carin A.T.C. Lunenburg; Femke M de Man; Didier Meulendijks; Gw Frederix; Emma Kienhuis; Geert-Jan Creemers; Arnold Baars; V. O. Dezentje; Alexander L T Imholz; Frank Jeurissen; Johanna Elisabeth A. Portielje; Rob L. Jansen; Paul Hamberg; Albert J. ten Tije; Helga J Droogendijk; Miriam Koopman; Peter Nieboer; Marlène H W van de Poel; Caroline M. Mandigers; Hilde Rosing; Jos H. Beijnen; Erik van Werkhoven; André B.P. van Kuilenburg; Ron H.N. van Schaik; Ron H.J. Mathijssen; Jesse J. Swen; Hans Gelderblom; Annemieke Cats; Henk-Jan Guchelaar

BACKGROUND Fluoropyrimidine treatment can result in severe toxicity in up to 30% of patients and is often the result of reduced activity of the key metabolic enzyme dihydropyrimidine dehydrogenase (DPD), mostly caused by genetic variants in the gene encoding DPD (DPYD). We assessed the effect of prospective screening for the four most relevant DPYD variants (DPYD*2A [rs3918290, c.1905+1G>A, IVS14+1G>A], c.2846A>T [rs67376798, D949V], c.1679T>G [rs55886062, DPYD*13, I560S], and c.1236G>A [rs56038477, E412E, in haplotype B3]) on patient safety and subsequent DPYD genotype-guided dose individualisation in daily clinical care. METHODS In this prospective, multicentre, safety analysis in 17 hospitals in the Netherlands, the study population consisted of adult patients (≥18 years) with cancer who were intended to start on a fluoropyrimidine-based anticancer therapy (capecitabine or fluorouracil as single agent or in combination with other chemotherapeutic agents or radiotherapy). Patients with all tumour types for which fluoropyrimidine-based therapy was considered in their best interest were eligible. We did prospective genotyping for DPYD*2A, c.2846A>T, c.1679T>G, and c.1236G>A. Heterozygous DPYD variant allele carriers received an initial dose reduction of 25% (c.2846A>T and c.1236G>A) or 50% (DPYD*2A and c.1679T>G), and DPYD wild-type patients were treated according to the current standard of care. The primary endpoint of the study was the frequency of severe (National Cancer Institute Common Terminology Criteria for Adverse Events version 4.03 grade ≥3) overall fluoropyrimidine-related toxicity across the entire treatment duration. We compared toxicity incidence between DPYD variant allele carriers and DPYD wild-type patients on an intention-to-treat basis, and relative risks (RRs) for severe toxicity were compared between the current study and a historical cohort of DPYD variant allele carriers treated with full dose fluoropyrimidine-based therapy (derived from a previously published meta-analysis). This trial is registered with ClinicalTrials.gov, number NCT02324452, and is complete. FINDINGS Between April 30, 2015, and Dec 21, 2017, we enrolled 1181 patients. 78 patients were considered non-evaluable, because they were retrospectively identified as not meeting inclusion criteria, did not start fluoropyrimidine-based treatment, or were homozygous or compound heterozygous DPYD variant allele carriers. Of 1103 evaluable patients, 85 (8%) were heterozygous DPYD variant allele carriers, and 1018 (92%) were DPYD wild-type patients. Overall, fluoropyrimidine-related severe toxicity was higher in DPYD variant carriers (33 [39%] of 85 patients) than in wild-type patients (231 [23%] of 1018 patients; p=0·0013). The RR for severe fluoropyrimidine-related toxicity was 1·31 (95% CI 0·63-2·73) for genotype-guided dosing compared with 2·87 (2·14-3·86) in the historical cohort for DPYD*2A carriers, no toxicity compared with 4·30 (2·10-8·80) in c.1679T>G carriers, 2·00 (1·19-3·34) compared with 3·11 (2·25-4·28) for c.2846A>T carriers, and 1·69 (1·18-2·42) compared with 1·72 (1·22-2·42) for c.1236G>A carriers. INTERPRETATION Prospective DPYD genotyping was feasible in routine clinical practice, and DPYD genotype-based dose reductions improved patient safety of fluoropyrimidine treatment. For DPYD*2A and c.1679T>G carriers, a 50% initial dose reduction was adequate. For c.1236G>A and c.2846A>T carriers, a larger dose reduction of 50% (instead of 25%) requires investigation. Since fluoropyrimidines are among the most commonly used anticancer agents, these findings suggest that implementation of DPYD genotype-guided individualised dosing should be a new standard of care. FUNDING Dutch Cancer Society.


European Journal of Pediatrics | 2018

Cost-effectiveness of rule-based immunoprophylaxis against respiratory syncytial virus infections in preterm infants

Maarten O. Blanken; Gw Frederix; Elisabeth E. Nibbelke; Hendrik Koffijberg; Elisabeth A. M. Sanders; M.M. Rovers; Louis Bont

AbstractThe objective of the paper is to assess the cost-effectiveness of targeted respiratory syncytial virus (RSV) prophylaxis based on a validated prediction rule with 1-year time horizon in moderately preterm infants compared to no prophylaxis. Data on health care consumption were derived from a randomised clinical trial on wheeze reduction following RSV prophylaxis and a large birth cohort study on risk prediction of RSV hospitalisation. We calculated the incremental cost-effectiveness ratio (ICER) of targeted RSV prophylaxis vs. no prophylaxis per quality-adjusted life year (QALYs) using a societal perspective, including medical and parental costs and effects. Costs and health outcomes were modelled in a decision tree analysis with sensitivity analyses. Targeted RSV prophylaxis in infants with a first-year RSV hospitalisation risk of > 10% resulted in a QALY gain of 0.02 (0.931 vs. 0.929) per patient against additional cost of €472 compared to no prophylaxis (ICER €214,748/QALY). The ICER falls below a threshold of €80,000 per QALY when RSV prophylaxis cost would be lowered from €928 (baseline) to €406 per unit. At a unit cost of €97, RSV prophylaxis would be cost saving. Conclusions: Targeted RSV prophylaxis is not cost-effective in reducing RSV burden of disease in moderately preterm infants, but it can become cost-effective if lower priced biosimilar palivizumab or a vaccine would be available.


Research in Social & Administrative Pharmacy | 2018

Pharmacy in transition: A work sampling study of community pharmacists using smartphone technology

Jeroen M. van de Pol; Jurjen G. Geljon; Gw Frederix; Anke M. Hövels; Marcel L. Bouvy

Introduction: The nature of community pharmacy is changing, shifting from the preparation and distribution of medicines to the provision of cognitive pharmaceutical services (CPS); however, often the provision of traditional services leaves little time for innovative services. This study investigated the time community pharmacists spend on the tasks and activities of daily practice and to what extent they are able to implement CPS‐related services in daily practice. Methods: Self‐reporting work sampling was used to register the activities of community pharmacists. A smartphone application, designed specifically for this purpose, alerted participants to register their current activity five times per working day for 6 weeks. Participants also completed an online survey about baseline characteristics. Results: Ninety‐one Dutch community pharmacists provided work‐sampling data (7848 registered activities). Overall, 51.5% of their time was spent on professional activities, 35.4% on semi‐professional activities, and 13.1% on non‐professional activities. The proportion of time devoted to CPS decreased during the workweek, whereas the time spent on traditional task increased. Discussion and conclusion: This study shows it is feasible to collect work‐sampling data using smartphone technology. Community pharmacists spent almost half of their time on semi‐professional and non‐professional activities, activities that could be delegated to other staff members. In practice, the transition to CPS is hampered by competing traditional tasks, which prevents community pharmacists from profiling themselves as pharmaceutical experts in daily practice.


British Journal of Clinical Pharmacology | 2016

Patient monitoring: the hidden costs of treatment with antipsychotics

Mariëtte Nederlof; Gw Frederix; Lennart J. Stoker; Wouter W. van Solinge; Toine C. G. Egberts; Eibert R. Heerdink

Antipsychotics are an important and frequently used treatment option for patients with schizophrenia. During treatment patients need to be monitored to determine effectiveness and safety, therefore total drug treatment costs also include the costs of patient monitoring. In this study we assess the proportion of patient monitoring as a part of antipsychotic treatment costs in patients with schizophrenia.


PharmacoEconomics | 2016

Unremarked or Unperformed? Systematic Review on Reporting of Validation Efforts of Health Economic Decision Models in Seasonal Influenza and Early Breast Cancer

Pieter T. de Boer; Gw Frederix; Talitha Feenstra; Pepijn Vemer


Journal of Public Health Policy | 2017

Health system productivity change in Zambia: A focus on the child health services

Tom Achoki; Yohannes Kinfu; Felix Masiye; Gw Frederix; Anke M. Hövels; Hubert G. M. Leufkens


Value in Health | 2015

Reimbursement of Orphan and Expensive Drugs In The Netherlands: Exploration of Essential Criteria In The Decision Making Process

L. Tariq; Gw Frederix; Rw Roberts; P van Bakel; J.A. Raaijmakers; Anke M. Hövels


WORLD HEALTH ORGANIZATION | 2014

RESEARCH AGENDA FOR HEALTH ECONOMIC EVALUATION

Gw Frederix; Pepijn Vemer


Annals of Oncology | 2018

452ODPYD genotype-guided dose individualization of fluoropyrimidine therapy: A prospective safety and cost-analysis on DPYD variants DPYD*2A, c.2846A>T, c.1679T>G and c.1236G>A

Linda M. Henricks; Carin A.T.C. Lunenburg; F M de Man; Didier Meulendijks; Gw Frederix; E Kienhuis; G-J M Creemers; Arnold Baars; V. O. Dezentje; Hilde Rosing; Jos H. Beijnen; E. van Werkhoven; A. B. P. van Kuilenburg; R.H.N. van Schaik; Ron H.J. Mathijssen; Jesse J. Swen; Hans Gelderblom; Annemieke Cats; H.-J. Guchelaar; Jan H. M. Schellens

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Jan H. M. Schellens

Netherlands Cancer Institute

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Pepijn Vemer

University of Groningen

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Annemieke Cats

Netherlands Cancer Institute

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Carin A.T.C. Lunenburg

Leiden University Medical Center

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Didier Meulendijks

Netherlands Cancer Institute

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Hans Gelderblom

Leiden University Medical Center

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Hilde Rosing

Netherlands Cancer Institute

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