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Featured researches published by Gerard H. Koëter.


PLOS ONE | 2016

Non-Publication Is Common among Phase 1, Single-Center, Not Prospectively Registered, or Early Terminated Clinical Drug Trials

Cornelis A. van den Bogert; Patrick C. Souverein; Cecile T.M. Brekelmans; Susan W.J. Janssen; Gerard H. Koëter; Hubert G. M. Leufkens; L.M. Bouter

The objective of this study was to investigate the occurrence and determinants of non-publication of clinical drug trials in the Netherlands.All clinical drug trials reviewed by the 28 Institutional Review Boards (IRBs) in the Netherlands in 2007 were followed-up from approval to publication. Candidate determinants were the sponsor, phase, applicant, centers, therapeutic effect expected, type of trial, approval status of the drug(s), drug type, participant category, oncology or other disease area, prospective registration, and early termination. The main outcome was publication as peer reviewed article. The percentage of trials that were published, crude and adjusted odds ratio (OR), and 95% confidence interval (CI) were used to quantify the associations between determinants and publication. In 2007, 622 clinical drug trials were reviewed by IRBs in the Netherlands. By the end of follow-up, 19 of these were rejected by the IRB, another 19 never started inclusion, and 10 were still running. Of the 574 trials remaining in the analysis, 334 (58%) were published as peer-reviewed article. The multivariable logistic regression model identified the following determinants with a robust, statistically significant association with publication: phase 2 (60% published; adjusted OR 2.6, 95% CI 1.1–5.9), phase 3 (73% published; adjusted OR 4.1, 95% CI 1.7–10.0), and trials not belonging to phase 1–4 (60% published; adjusted OR 3.2, 95% CI 1.5 to 6.5) compared to phase 1 trials (35% published); trials with a company or investigator as applicant (63% published) compared to trials with a Contract Research Organization (CRO) as applicant (50% published; adjusted OR 1.7; 95% CI 1.1–2.8); and multicenter trials also conducted in other EU countries (68% published; adjusted OR 2.2, 95% CI 1.1–4.4) or also outside the European Union (72% published; adjusted OR 2.0, 95% CI 1.0–4.0) compared to single-center trials (45% published). Trials that were not prospectively registered (48% published) had a lower likelihood of publication compared to prospectively registered trials (75% published; adjusted OR 0.5, 95% CI 0.3–0.8), as well as trials that were terminated early (33% published) compared to trials that were completed as planned (64% published; adjusted OR 0.2, 95% CI 0.1–0.3). The non-publication rate of clinical trials seems to have improved compared to previous inception cohorts, but is still far from optimal, in particular among phase 1, single-center, not prospectively registered, and early terminated trials.


BMJ Open | 2015

Occurrence and determinants of selective reporting of clinical drug trials: design of an inception cohort study

Cornelis A. van den Bogert; Patrick C. Souverein; Cecile T.M. Brekelmans; Susan W.J. Janssen; Manon van Hunnik; Gerard H. Koëter; Hubertus G. M. Leufkens; L.M. Bouter

Introduction Responsible conduct of research implies that results of clinical trials should be completely and adequately reported. This article describes the design of a cohort study that aims to investigate the occurrence and the determinants of selective reporting in an inception cohort of all clinical drug trials that were reviewed by the Dutch Institutional Review Boards (IRBs) in 2007. It also describes the characteristics of the study cohort. Methods and analysis In 2007, Dutch IRBs reviewed 622 clinical drug trials. For each trial, we assessed the stages of progress. We discriminated five intermediate stages and five definite stages. Intermediate stages of progress are: approved by an IRB; started inclusion; completed as planned; terminated early; published as article. The definite stages of progress are: rejected by an IRB; never started inclusion; not published as article; completely reported; selectively reported. We will use univariate and multivariate Cox regression models to identify trial characteristics associated with non-publication. We will identify seven trial-specific discrepancy items, including the objectives, inclusion and exclusion criteria, end points, sample size, additional analyses, type of population analysis and sponsor acknowledgement. The percentage of trials with discrepancies between the protocol and the publication will be scored. We will investigate the association between trial characteristics and the occurrence of discrepancies. Ethics and dissemination No IRB-approval is required for this study. Access to confidential research protocols was provided by the Central Committee on Research Involving Human Subjects. We plan to finish data collection in June 2015, and expect to complete data cleaning, analysis and manuscript preparation within the next 3 months. Hence, a first draft of an article containing the results is expected before the end of October 2015.


Journal of Clinical Epidemiology | 2017

Recruitment failure and futility were the most common reasons for discontinuation of clinical drug trials. Results of a nationwide inception cohort study in the Netherlands

Cornelis A. van den Bogert; Patrick C. Souverein; Cecile T.M. Brekelmans; Susan W.J. Janssen; Gerard H. Koëter; Hubert G. M. Leufkens; L.M. Bouter

OBJECTIVES The objective of the study was to identify the reasons for discontinuation of clinical drug trials and to evaluate whether efficacy-related discontinuations were adequately planned in the trial protocol. STUDY DESIGN AND SETTING All clinical drug trials in the Netherlands, reviewed by institutional review boards in 2007, were followed until December 2015. Data were obtained through the database of the Dutch competent authority (Central Committee on Research Involving Human Subjects [CCMO]) and a questionnaire to the principal investigators. Reasons for trial discontinuation were the primary outcome of the study. Three reasons for discontinuation were analyzed separately: all cause, recruitment failure, and efficacy related (when an interim analysis had demonstrated futility or superiority). Among the efficacy-related discontinuations, we examined whether the data monitoring committee, the stopping rule, and the moment of the interim analysis in the trial progress were specified in the trial protocol. RESULTS Of the 574 trials, 102 (17.8%) were discontinued. The most common reasons were recruitment failure (33 of 574; 5.7%) and solely efficacy related (30 of 574; 5.2%). Of the efficacy-related discontinuations, 10 of 30 (33.3%) of the trial protocols reported all three aspects in the trial protocol, and 20 of 30 (66.7%) reported at least one aspect in the trial protocol. CONCLUSION One out of five clinical drug trials is discontinued before the planned trial end, with recruitment failure and futility as the most common reasons. The target sample size of trials should be feasible, and interim analyses should be adequately described in trial protocols.


Nature Reviews Drug Discovery | 2014

Regulatory watch: Outcomes of EMA marketing authorization applications: does partnering have an influence?

Cornelis A. van den Bogert; Patrick C. Souverein; Michelle Putzeist; Hubert G. M. Leufkens; Susan W.J. Janssen; Gerard H. Koëter

Regulatory watch: Outcomes of EMA marketing authorization applications: does partnering have an influence?


Journal of Clinical Epidemiology | 2017

Primary endpoint discrepancies were found in one in ten clinical drug trials. Results of an inception cohort study

Cornelis A. van den Bogert; Patrick C. Souverein; Cecile T.M. Brekelmans; Susan W.J. Janssen; Gerard H. Koëter; Hubert G. M. Leufkens; L.M. Bouter


Pharmacoepidemiology and Drug Safety | 2017

Discrepancies Between Protocols and Publications of Clinical Drug Trials

Cornelis A. van den Bogert; Patrick C. Souverein; Cecile T.M. Brekelmans; Susan W.J. Janssen; Gerard H. Koëter; Hubert G. M. Leufkens; L.M. Bouter


Nederlands Tijdschrift voor Geneeskunde | 2017

Hoeveel klinische geneesmiddelenstudies worden uiteindelijk gepubliceerd?. Fase 1-studies blijven achter in aantal publicaties

C. A. Van Den Bogert; Patrick C. Souverein; Cecile T.M. Brekelmans; Susan W.J. Janssen; Gerard H. Koëter; Hubertus G. M. Leufkens; L.M. Bouter


BMJ Open | 2015

Occurrence and determinants of selective reporting of clinical drug trials: design and characteristics of an inception cohort study.

C.A. van den Bogert; Patrick C. Souverein; Cecile T.M. Brekelmans; Susan W.J. Janssen; M van Hunik; Gerard H. Koëter; Hubertus G. M. Leufkens; L.M. Bouter; Vu


Nederlands Tijdschrift voor Geneeskunde | 2011

Patiëntveiligheid bij klinisch interventieonderzoek

Cecile T.M. Brekelmans; M.J.H. Kenter; L.M. Bouter; Gerard H. Koëter; Vu; Vu medisch centrum

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L.M. Bouter

VU University Medical Center

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Vu

VU University Medical Center

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