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Day S, Jonker AH, Lau LPL, Hilgers RD, Irony I, Larsson K, Roes KC, Stallard N. Recommendations for the design of small population clinical trials. Orphanet J Rare Dis 2018; 13:195. [PMID: 30400970 PMCID: PMC6219020 DOI: 10.1186/s13023-018-0931-2] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 10/09/2018] [Indexed: 02/08/2023] Open
Abstract
Background Orphan drug development faces numerous challenges, including low disease prevalence, patient population heterogeneity, and strong presence of paediatric patient populations. Consequently, clinical trials for orphan drugs are often smaller than those of non-orphan drugs, and they require the development of efficient trial designs relevant to small populations to gain the most information from the available data. The International Rare Diseases Research Consortium (IRDiRC) is aimed at promoting international collaboration and advance rare diseases research worldwide, and has as one of its goals to contribute to 1000 new therapies for rare diseases. IRDiRC set up a Small Population Clinical Trials (SPCT) Task Force in order to address the shortcomings of our understanding in carrying out clinical trials in rare diseases. Results The IRDiRC SPCT Task Force met in March 2016 to discuss challenges faced in the design of small studies for rare diseases and present their recommendations, structured around six topics: different study methods/designs and their relation to different characteristics of medical conditions, adequate safety data, multi-arm trial designs, decision analytic approaches and rational approaches to adjusting levels of evidence, extrapolation, and patients’ engagement in study design. Conclusions Recommendations have been issued based on discussions of the Small Population Clinical Trials Task Force that aim to contribute towards successful therapy development and clinical use. While randomised clinical trials are still considered the gold standard, it is recommended to systematically take into consideration alternative trial design options when studying treatments for a rare disease. Combining different sources of safety data is important to give a fuller picture of a therapy’s safety profile. Multi-arm trials should be considered an opportunity for rare diseases therapy development, and funders are encouraged to support such trial design via international networks. Patient engagement is critical in trial design and therapy development, a process which sponsors are encouraged to incorporate when conducting trials and clinical studies. Input from multiple regulatory agencies is recommended early and throughout clinical development. Regulators are often supportive of new clinical trial designs, provided they are well thought through and justified, and they also welcome discussions and questions on this topic. Parallel advice for multiregional development programs should also be considered.
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Affiliation(s)
- Simon Day
- Clinical Trials Consulting & Training Limited, 53 Portway, North Marston, Buckingham, Buckinghamshire, MK18 3PL, UK.
| | | | | | | | - Ilan Irony
- Center for Biologics Evaluation and Research/ Office of Tissues and Advanced Therapies, US Food and Drug Administration, Silver Spring, USA
| | | | - Kit Cb Roes
- Julius Center for Health Sciences and Primary Care, UMC Utrecht, Utrecht, The Netherlands
| | - Nigel Stallard
- Statistics and Epidemiology, Warwick Medical School, University of Warwick, Coventry, UK
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van Hoeven LR, Kreuger AL, Roes KC, Kemper PF, Koffijberg H, Kranenburg FJ, Rondeel JM, Janssen MP. Why was this transfusion given? Identifying clinical indications for blood transfusion in health care data. Clin Epidemiol 2018; 10:353-362. [PMID: 29636633 PMCID: PMC5881526 DOI: 10.2147/clep.s147142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background To enhance the utility of transfusion data for research, ideally every transfusion should be linked to a primary clinical indication. In electronic patient records, many diagnostic and procedural codes are registered, but unfortunately, it is usually not specified which one is the reason for transfusion. Therefore, a method is needed to determine the most likely indication for transfusion in an automated way. Study design and methods An algorithm to identify the most likely transfusion indication was developed and evaluated against a gold standard based on the review of medical records for 234 cases by 2 experts. In a second step, information on misclassification was used to fine-tune the initial algorithm. The adapted algorithm predicts, out of all data available, the most likely indication for transfusion using information on medical specialism, surgical procedures, and diagnosis and procedure dates relative to the transfusion date. Results The adapted algorithm was able to predict 74.4% of indications in the sample correctly (extrapolated to the full data set 75.5%). A kappa score, which corrects for the number of options to choose from, was found of 0.63. This indicates that the algorithm performs substantially better than chance level. Conclusion It is possible to use an automated algorithm to predict the indication for transfusion in terms of procedures and/or diagnoses. Before implementation of the algorithm in other data sets, the obtained results should be externally validated in an independent hospital data set.
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Affiliation(s)
- Loan R van Hoeven
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands.,Transfusion Technology Assessment Department, Sanquin Research, Amsterdam, the Netherlands
| | - Aukje L Kreuger
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands.,Center for Clinical Transfusion Research, Sanquin Research, Leiden, the Netherlands
| | - Kit Cb Roes
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Peter F Kemper
- Transfusion Technology Assessment Department, Sanquin Research, Amsterdam, the Netherlands.,Center for Clinical Transfusion Research, Sanquin Research, Leiden, the Netherlands
| | - Hendrik Koffijberg
- Department of Health Technology & Services Research, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, the Netherlands
| | - Floris J Kranenburg
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands.,Center for Clinical Transfusion Research, Sanquin Research, Leiden, the Netherlands.,Department of Intensive Care, Leiden University Medical Center, Leiden, the Netherlands
| | - Jan Mm Rondeel
- Department of Clinical Chemistry, Isala, Zwolle, the Netherlands
| | - Mart P Janssen
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands.,Transfusion Technology Assessment Department, Sanquin Research, Amsterdam, the Netherlands
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Nikolakopoulos S, Roes KC, van der Tweel I. Sequential designs with small samples: Evaluation and recommendations for normal responses. Stat Methods Med Res 2016; 27:1115-1127. [PMID: 27342574 DOI: 10.1177/0962280216653778] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Sequential monitoring is a well-known methodology for the design and analysis of clinical trials. Driven by the lower expected sample size, recent guidelines and published research suggest the use of sequential methods for the conduct of clinical trials in rare diseases. However, the vast majority of the developed and most commonly used sequential methods relies on asymptotic assumptions concerning the distribution of the test statistics. It is not uncommon for trials in (very) rare diseases to be conducted with only a few decades of patients and the use of sequential methods that rely on large-sample approximations could inflate the type I error probability. Additionally, the setting of a rare disease could make the traditional paradigm of designing a clinical trial (deciding on the sample size given type I and II errors and anticipated effect size) irrelevant. One could think of the situation where the number of patients available has a maximum and this should be utilized in the most efficient way. In this work, we evaluate the operational characteristics of sequential designs in the setting of very small to moderate sample sizes with normally distributed outcomes and demonstrate the necessity of simple corrections of the critical boundaries. We also suggest a method for deciding on an optimal sequential design given a maximum sample size and some (data driven or based on expert opinion) prior belief on the treatment effect.
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Affiliation(s)
- Stavros Nikolakopoulos
- Department of Biostatistics and Research Support, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Kit Cb Roes
- Department of Biostatistics and Research Support, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ingeborg van der Tweel
- Department of Biostatistics and Research Support, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
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Novianti PW, van der Tweel I, Jong VL, Roes KC, Eijkemans MJ. An Application of Sequential Meta-Analysis to Gene Expression Studies. Cancer Inform 2015; 14:1-10. [PMID: 26401096 PMCID: PMC4567049 DOI: 10.4137/cin.s27718] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 06/03/2015] [Accepted: 06/04/2015] [Indexed: 11/15/2022] Open
Abstract
Most of the discoveries from gene expression data are driven by a study claiming an optimal subset of genes that play a key role in a specific disease. Meta-analysis of the available datasets can help in getting concordant results so that a real-life application may be more successful. Sequential meta-analysis (SMA) is an approach for combining studies in chronological order while preserving the type I error and pre-specifying the statistical power to detect a given effect size. We focus on the application of SMA to find gene expression signatures across experiments in acute myeloid leukemia. SMA of seven raw datasets is used to evaluate whether the accumulated samples show enough evidence or more experiments should be initiated. We found 313 differentially expressed genes, based on the cumulative information of the experiments. SMA offers an alternative to existing methods in generating a gene list by evaluating the adequacy of the cumulative information.
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Affiliation(s)
- Putri W Novianti
- Biostatistics and Research Support, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ingeborg van der Tweel
- Biostatistics and Research Support, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Victor L Jong
- Biostatistics and Research Support, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands ; Department of Viroscience, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Kit Cb Roes
- Biostatistics and Research Support, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marinus Jc Eijkemans
- Biostatistics and Research Support, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
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Abstract
In drug development and drug licensing, it sometimes occurs that a new drug does not demonstrate effectiveness for the full study population, but there appears to be benefit in a relevant, pre-defined subgroup. This raises the question, how strong the evidence from such a subgroup is, and which confirmatory testing strategies are the most appropriate ones. Hence, we considered the type I error and the power of a subgroup result in a trial with non-significant overall results and of suitable replication strategies. In the case of a single trial, the inflation of the overall type I error is substantial and can be up to twice as large, especially in relatively small subgroups. This also increases to the risk of starting a replication trial that should not be done, if such a second trial is not already available. The overall type I error is almost controlled by using an appropriate replication strategy. This confirms the required cautious interpretation of promising subgroups, even in the case that overall trial results were perceived to be close to significance.
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Affiliation(s)
- Julien Tanniou
- Julius Center for Health Sciences and Primary Care, UMC Utrecht, The Netherlands Medicines Evaluation Board, College ter Beoordeling van Geneesmiddelen, Utrecht, The Netherlands
| | | | - Steven Teerenstra
- Medicines Evaluation Board, College ter Beoordeling van Geneesmiddelen, Utrecht, The Netherlands Department of Health Evidence, Biostatistics Section, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Kit Cb Roes
- Julius Center for Health Sciences and Primary Care, UMC Utrecht, The Netherlands Medicines Evaluation Board, College ter Beoordeling van Geneesmiddelen, Utrecht, The Netherlands
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Van Eijk MM, Roes KC, Honing ML, Kuiper MA, Karakus A, Van der JAgt M, Spronk PE, Van Gool WA, Van der Mast RC, Kesecioglu J, Slooter AJ. Effect of rivastigmine as an adjunct to usual care with haloperidol on duration of delirium and mortality in critically ill patients: a multicentre, double-blind, placebo-controlled randomised trial. Crit Care 2011. [PMCID: PMC3067013 DOI: 10.1186/cc9759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Radhakishun FS, van den Bos J, van der Heijden BC, Roes KC, O'Hanlon JF. Mirtazapine effects on alertness and sleep in patients as recorded by interactive telecommunication during treatment with different dosing regimens. J Clin Psychopharmacol 2000; 20:531-7. [PMID: 11001237 DOI: 10.1097/00004714-200010000-00006] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This double-blind study compared mirtazapine's effects on alertness and sleep between parallel groups treated for 2 weeks according to a fixed regimen of 30 mg at bedtime (N = 69) and one that increased in dose from 15 to 30 mg at bedtime after the first week (N = 71). These patients with depression used an interactive telephone/computer system for daily alertness and sleep recordings on self-rating scales before and during treatment. Efficacy (17-item Hamilton Rating Scale for Depression [HAM-D], Clinical Global Impression Scale [CGI]) and safety assessments were made by participating psychiatrists. Both groups' alertness ratings were subnormal at baseline and even lower after the first dose. The ratings recovered after the second dose and increased progressively to levels 18% higher than those at baseline by the end of treatment. Patients receiving the fixed dose reported earlier sleep onset and longer duration. Similar mean changes in HAM-D scores (approximately -40%) and frequencies of CGI responders (>50%) occurred in both groups. The regimens were equally well tolerated. Somnolence, the most frequent side effect, was reported by only 10% of each group during the first week and by fewer patients during the second. Mirtazapine in fixed and ascending nocturnal dosing regimens was found to facilitate sleep, but it does not generally reduce daytime alertness. The fixed regimen seems preferable because of its greater effects on sleep.
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Abstract
To assess the efficacy of potential new drugs in the initial phase of clinical research, one must use an efficient design that satisfies conditions to guarantee the safety of the subjects. For a parallel design, a two-period crossover design, two three-period crossover designs, and a Latin square design with three periods, we compared variances of estimators based on a mixed analysis of variance model. The proposed three-period crossover designs turned out to be only slightly less efficient than the Latin square design, which is not capable of satisfying the necessary safety conditions. The analysis of data from the crossover design poses several problems, including nonconstant variances for all observations and the possibility of carryover effects. To resolve these issues, we generalized the Box-Cox transformations to the mixed model at hand and, using simulation, investigated the sensitivity of the analysis to the presence of (first-order) carryover effects. This showed that results from the model without carryover are reliable for only very small carryover effects.
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Affiliation(s)
- P C Boon
- Faculty of Applied Mathematics, University of Twente, Enschede, The Netherlands
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Kasper S, Zivkov M, Roes KC, Pols AG. Pharmacological treatment of severely depressed patients: a meta-analysis comparing efficacy of mirtazapine and amitriptyline. Eur Neuropsychopharmacol 1997; 7:115-24. [PMID: 9169299 DOI: 10.1016/s0924-977x(96)00394-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Efficacy data were available from 405 severely depressed patients (baseline 17-item Hamilton Rating Scale for Depression-HAMD scores > or = 25) participating in randomized, double-blind, amitriptyline-controlled studies of mirtazapine. Main efficacy variable were changes from baseline in the group mean 17-item HAMD scores and responder rates. Secondary efficacy variables were changes in depressed mood item on the HAMD and in factors derived from the 17-item HAMD scale. Treatment with either mirtazapine or amitriptyline resulted in robust reductions of baseline HAMD scores and in similar and high percentages of responders. Both drugs produced favourable effects on depressed mood and on symptoms commonly associated with depression, such as anxiety, sleep and vegetative disturbances. There were neither statistically significant nor clinically relevant differences between mirtazapine and amitriptyline at any assessment point nor at endpoint. The results demonstrate that the new antidepressant mirtazapine and the tricyclic antidepressant amitriptyline are equally effective in the treatment of severely depressed patients.
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Affiliation(s)
- S Kasper
- Department of General Psychiatry, University of Vienna, Austria
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