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Barnett H, George M, Skanji D, Saint-Hilary G, Jaki T, Mozgunov P. A comparison of model-free phase I dose escalation designs for dual-agent combination therapies. Stat Methods Med Res 2024; 33:203-226. [PMID: 38263903 PMCID: PMC10928960 DOI: 10.1177/09622802231220497] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
It is increasingly common for therapies in oncology to be given in combination. In some cases, patients can benefit from the interaction between two drugs, although often at the risk of higher toxicity. A large number of designs to conduct phase I trials in this setting are available, where the objective is to select the maximum tolerated dose combination. Recently, a number of model-free (also called model-assisted) designs have provoked interest, providing several practical advantages over the more conventional approaches of rule-based or model-based designs. In this paper, we demonstrate a novel calibration procedure for model-free designs to determine their most desirable parameters. Under the calibration procedure, we compare the behaviour of model-free designs to model-based designs in a comprehensive simulation study, covering a number of clinically plausible scenarios. It is found that model-free designs are competitive with the model-based designs in terms of the proportion of correct selections of the maximum tolerated dose combination. However, there are a number of scenarios in which model-free designs offer a safer alternative. This is also illustrated in the application of the designs to a case study using data from a phase I oncology trial.
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Affiliation(s)
- Helen Barnett
- Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
| | - Matthew George
- Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
- Phastar London, UK
| | | | | | - Thomas Jaki
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
- University of Regensburg, Regensburg, Germany
| | - Pavel Mozgunov
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
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2
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Kasianova K, Kelbert M, Mozgunov P. Response-adaptive randomization for multiarm clinical trials using context-dependent information measures. Biom J 2023; 65:e2200301. [PMID: 37816142 DOI: 10.1002/bimj.202200301] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 05/10/2023] [Accepted: 06/16/2023] [Indexed: 10/12/2023]
Abstract
Theoretical-information approach applied to the clinical trial designs appeared to bring several advantages when tackling a problem of finding a balance between power and expected number of successes (ENS). In particular, it was shown that the built-in parameter of the weight function allows finding the desired trade-off between the statistical power and number of treated patients in the context of small population Phase II clinical trials. However, in real clinical trials, randomized designs are more preferable. The goal of this research is to introduce randomization to a deterministic entropy-based sequential trial procedure generalized to multiarm setting. Several methods of randomization applied to an entropy-based design are investigated in terms of statistical power and ENS. Namely, the four design types are considered: (a) deterministic procedures, (b) naive randomization using the inverse of entropy criteria as weights, (c) block randomization, and (d) randomized penalty parameter. The randomized entropy-based designs are compared to randomized Gittins index (GI) and fixed randomization (FR). After the comprehensive simulation study, the following conclusion on block randomization is made: for both entropy-based and GI-based block randomization designs the degree of randomization induced by forward-looking procedures is insufficient to achieve a decent statistical power. Therefore, we propose an adjustment for the forward-looking procedure that improves power with almost no cost in terms of ENS. In addition, the properties of randomization procedures based on randomly drawn penalty parameter are also thoroughly investigated.
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Affiliation(s)
- Ksenia Kasianova
- Faculty of Economics, National Research University Higher School of Economics, Moscow, Russia
| | - Mark Kelbert
- Faculty of Economics, National Research University Higher School of Economics, Moscow, Russia
| | - Pavel Mozgunov
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
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3
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Daniells L, Mozgunov P, Bedding A, Jaki T. A comparison of Bayesian information borrowing methods in basket trials and a novel proposal of modified exchangeability-nonexchangeability method. Stat Med 2023; 42:4392-4417. [PMID: 37614070 PMCID: PMC10962580 DOI: 10.1002/sim.9867] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 07/12/2023] [Accepted: 07/24/2023] [Indexed: 08/25/2023]
Abstract
Recent innovation in trial design to improve study efficiency has led to the development of basket trials in which a single therapeutic treatment is tested on several patient populations, each of which forms a basket. In a common setting, patients across all baskets share a genetic marker and as such, an assumption can be made that all patients may have a homogeneous response to treatments. Bayesian information borrowing procedures utilize this assumption to draw on information regarding the response in one basket when estimating the response rate in others. This can improve power and precision of estimates particularly in the presence of small sample sizes, however, can come at a cost of biased estimates and an inflation of error rates, bringing into question validity of trial conclusions. We review and compare the performance of several Bayesian borrowing methods, namely: the Bayesian hierarchical model (BHM), calibrated Bayesian hierarchical model (CBHM), exchangeability-nonexchangeability (EXNEX) model and a Bayesian model averaging procedure. A generalization of the CBHM is made to account for unequal sample sizes across baskets. We also propose a modification of the EXNEX model that allows for better control of a type I error. The proposed method uses a data-driven approach to account for the homogeneity of the response data, measured through Hellinger distances. Through an extensive simulation study motivated by a real basket trial, for both equal and unequal sample sizes across baskets, we show that in the presence of a basket with a heterogeneous response, unlike the other methods discussed, this model can control type I error rates to a nominal level whilst yielding improved power.
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Affiliation(s)
- Libby Daniells
- STOR‐i Centre for Doctoral Training, Department of Mathematics and StatisticsLancaster UniversityLancasterUK
| | - Pavel Mozgunov
- MRC Biostatistics UnitUniversity of CambridgeCambridgeUK
| | | | - Thomas Jaki
- MRC Biostatistics UnitUniversity of CambridgeCambridgeUK
- Faculty of Informatics and Data ScienceUniversity of RegensburgRegensburgGermany
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4
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Zheng H, Grayling MJ, Mozgunov P, Jaki T, Wason JMS. Bayesian sample size determination in basket trials borrowing information between subsets. Biostatistics 2023; 24:1000-1016. [PMID: 35993875 DOI: 10.1093/biostatistics/kxac033] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 07/22/2022] [Accepted: 07/29/2022] [Indexed: 12/31/2022] Open
Abstract
Basket trials are increasingly used for the simultaneous evaluation of a new treatment in various patient subgroups under one overarching protocol. We propose a Bayesian approach to sample size determination in basket trials that permit borrowing of information between commensurate subsets. Specifically, we consider a randomized basket trial design where patients are randomly assigned to the new treatment or control within each trial subset ("subtrial" for short). Closed-form sample size formulae are derived to ensure that each subtrial has a specified chance of correctly deciding whether the new treatment is superior to or not better than the control by some clinically relevant difference. Given prespecified levels of pairwise (in)commensurability, the subtrial sample sizes are solved simultaneously. The proposed Bayesian approach resembles the frequentist formulation of the problem in yielding comparable sample sizes for circumstances of no borrowing. When borrowing is enabled between commensurate subtrials, a considerably smaller trial sample size is required compared to the widely implemented approach of no borrowing. We illustrate the use of our sample size formulae with two examples based on real basket trials. A comprehensive simulation study further shows that the proposed methodology can maintain the true positive and false positive rates at desired levels.
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Affiliation(s)
- Haiyan Zheng
- MRC Biostatistics Unit, University of Cambridge, Cambridge, CB2 0SR, UK and Population Health Sciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, UK
| | - Michael J Grayling
- Population Health Sciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, UK
| | - Pavel Mozgunov
- MRC Biostatistics Unit, University of Cambridge, Cambridge, CB2 0SR, UK
| | - Thomas Jaki
- MRC Biostatistics Unit, University of Cambridge, Cambridge, CB2 0SR, UK and University of Regensburg, 93040 Regensburg, Germany
| | - James M S Wason
- Population Health Sciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, UK
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5
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Serra A, Mozgunov P, Davies G, Jaki T. Determining the minimum duration of treatment in tuberculosis: An order restricted non-inferiority trial design. Pharm Stat 2023; 22:938-962. [PMID: 37415394 DOI: 10.1002/pst.2320] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 04/22/2023] [Accepted: 06/20/2023] [Indexed: 07/08/2023]
Abstract
Tuberculosis (TB) is one of the biggest killers among infectious diseases worldwide. Together with the identification of drugs that can provide benefits to patients, the challenge in TB is also the optimisation of the duration of these treatments. While conventional duration of treatment in TB is 6 months, there is evidence that shorter durations might be as effective but could be associated with fewer side effects and may be associated with better adherence. Based on a recent proposal of an adaptive order-restricted superiority design that employs the ordering assumptions within various duration of the same drug, we propose a non-inferiority (typically used in TB trials) adaptive design that effectively uses the order assumption. Together with the general construction of the hypothesis testing and expression for type I and type II errors, we focus on how the novel design was proposed for a TB trial concept. We consider a number of practical aspects such as choice of the design parameters, randomisation ratios, and timings of the interim analyses, and how these were discussed with the clinical team.
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Affiliation(s)
| | - Pavel Mozgunov
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - Geraint Davies
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Thomas Jaki
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
- Faculty of Informatics and Data Science, University of Regensburg, Regensburg, Germany
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Jaki T, Burdon A, Chen X, Mozgunov P, Zheng H, Baird R. Early phase clinical trials in oncology: Realising the potential of seamless designs. Eur J Cancer 2023; 189:112916. [PMID: 37301716 PMCID: PMC7614750 DOI: 10.1016/j.ejca.2023.05.005] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 06/12/2023]
Abstract
BACKGROUND The pharmaceutical industry's productivity has been declining over the last two decades and high attrition rates and reduced regulatory approvals are being seen. The development of oncology drugs is particularly challenging with low rates of approval for novel treatments when compared with other therapeutic areas. Reliably establishing the potential of novel treatment and the corresponding optimal dosage is a key component to ensure efficient overall development. A growing interest lies in terminating developments of poor treatments quickly while enabling accelerated development for highly promising interventions. METHODS One approach to reliably establish the optimal dosage and the potential of a novel treatment and thereby improve efficiency in the drug development pathway is the use of novel statistical designs that make efficient use of the data collected. RESULTS In this paper, we discuss different (seamless) strategies for early oncology development and illustrate their strengths and weaknesses through real trial examples. We provide some directions for good practices in early oncology development, discuss frequently seen missed opportunities for improved efficiency and some future opportunities that have yet to fully develop their potential in early oncology treatment development. DISCUSSION Modern methods for dose-finding have the potential to shorten and improve dose-finding and only small changes to current approaches are required to realise this potential.
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Affiliation(s)
- Thomas Jaki
- MRC Biostatistics Unit, University of Cambridge, UK; University of Regensburg, Germany.
| | | | - Xijin Chen
- MRC Biostatistics Unit, University of Cambridge, UK
| | | | - Haiyan Zheng
- MRC Biostatistics Unit, University of Cambridge, UK
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7
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Serra A, Mozgunov P, Jaki T. A Bayesian multi-arm multi-stage clinical trial design incorporating information about treatment ordering. Stat Med 2023; 42:2841-2854. [PMID: 37158302 PMCID: PMC10962588 DOI: 10.1002/sim.9752] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 01/27/2023] [Accepted: 04/13/2023] [Indexed: 05/10/2023]
Abstract
Multi-Arm Multi-Stage (MAMS) designs can notably improve efficiency in later stages of drug development, but they can be suboptimal when an order in the effects of the arms can be assumed. In this work, we propose a Bayesian multi-arm multi-stage trial design that selects all promising treatments with high probability and can efficiently incorporate information about the order in the treatment effects as well as incorporate prior knowledge on the treatments. A distinguishing feature of the proposed design is that it allows taking into account the uncertainty of the treatment effect order assumption and does not assume any parametric arm-response model. The design can provide control of the family-wise error rate under specific values of the control mean and we illustrate its operating characteristics in a study of symptomatic asthma. Via simulations, we compare the novel Bayesian design with frequentist multi-arm multi-stage designs and a frequentist order restricted design that does not account for the order uncertainty and demonstrate the gains in the sample sizes the proposed design can provide. We also find that the proposed design is robust to violations of the assumptions on the order.
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Affiliation(s)
| | - Pavel Mozgunov
- MRC Biostatistics UnitUniversity of CambridgeCambridgeUK
| | - Thomas Jaki
- MRC Biostatistics UnitUniversity of CambridgeCambridgeUK
- Faculty for Informatics and Data ScienceUniversity of RegensburgRegensburgGermany
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8
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Khoo SH, FitzGerald R, Saunders G, Middleton C, Ahmad S, Edwards CJ, Hadjiyiannakis D, Walker L, Lyon R, Shaw V, Mozgunov P, Periselneris J, Woods C, Bullock K, Hale C, Reynolds H, Downs N, Ewings S, Buadi A, Cameron D, Edwards T, Knox E, Donovan-Banfield I, Greenhalf W, Chiong J, Lavelle-Langham L, Jacobs M, Northey J, Painter W, Holman W, Lalloo DG, Tetlow M, Hiscox JA, Jaki T, Fletcher T, Griffiths G, Hayden F, Darbyshire J, Lucas A, Lorch U, Freedman A, Knight R, Julious S, Byrne R, Cubas Atienzar A, Jones J, Williams C, Song A, Dixon J, Alexandersson A, Hatchard P, Tilt E, Titman A, Doce Carracedo A, Chandran Gorner V, Davies A, Woodhouse L, Carlucci N, Okenyi E, Bula M, Dodd K, Gibney J, Dry L, Rashid Gardner Z, Sammour A, Cole C, Rowland T, Tsakiroglu M, Yip V, Osanlou R, Stewart A, Parker B, Turgut T, Ahmed A, Starkey K, Subin S, Stockdale J, Herring L, Baker J, Oliver A, Pacurar M, Owens D, Munro A, Babbage G, Faust S, Harvey M, Pratt D, Nagra D, Vyas A. Molnupiravir versus placebo in unvaccinated and vaccinated patients with early SARS-CoV-2 infection in the UK (AGILE CST-2): a randomised, placebo-controlled, double-blind, phase 2 trial. Lancet Infect Dis 2023; 23:183-195. [PMID: 36272432 PMCID: PMC9662684 DOI: 10.1016/s1473-3099(22)00644-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/06/2022] [Accepted: 09/12/2022] [Indexed: 11/06/2022]
Abstract
BACKGROUND The antiviral drug molnupiravir was licensed for treating at-risk patients with COVID-19 on the basis of data from unvaccinated adults. We aimed to evaluate the safety and virological efficacy of molnupiravir in vaccinated and unvaccinated individuals with COVID-19. METHODS This randomised, placebo-controlled, double-blind, phase 2 trial (AGILE CST-2) was done at five National Institute for Health and Care Research sites in the UK. Eligible participants were adult (aged ≥18 years) outpatients with PCR-confirmed, mild-to-moderate SARS-CoV-2 infection who were within 5 days of symptom onset. Using permuted blocks (block size 2 or 4) and stratifying by site, participants were randomly assigned (1:1) to receive either molnupiravir (orally; 800 mg twice daily for 5 days) plus standard of care or matching placebo plus standard of care. The primary outcome was the time from randomisation to SARS-CoV-2 PCR negativity on nasopharyngeal swabs and was analysed by use of a Bayesian Cox proportional hazards model for estimating the probability of a superior virological response (hazard ratio [HR]>1) for molnupiravir versus placebo. Our primary model used a two-point prior based on equal prior probabilities (50%) that the HR was 1·0 or 1·5. We defined a priori that if the probability of a HR of more than 1 was more than 80% molnupiravir would be recommended for further testing. The primary outcome was analysed in the intention-to-treat population and safety was analysed in the safety population, comprising participants who had received at least one dose of allocated treatment. This trial is registered in ClinicalTrials.gov, NCT04746183, and the ISRCTN registry, ISRCTN27106947, and is ongoing. FINDINGS Between Nov 18, 2020, and March 16, 2022, 1723 patients were assessed for eligibility, of whom 180 were randomly assigned to receive either molnupiravir (n=90) or placebo (n=90) and were included in the intention-to-treat analysis. 103 (57%) of 180 participants were female and 77 (43%) were male and 90 (50%) participants had received at least one dose of a COVID-19 vaccine. SARS-CoV-2 infections with the delta (B.1.617.2; 72 [40%] of 180), alpha (B.1.1.7; 37 [21%]), omicron (B.1.1.529; 38 [21%]), and EU1 (B.1.177; 28 [16%]) variants were represented. All 180 participants received at least one dose of treatment and four participants discontinued the study (one in the molnupiravir group and three in the placebo group). Participants in the molnupiravir group had a faster median time from randomisation to negative PCR (8 days [95% CI 8-9]) than participants in the placebo group (11 days [10-11]; HR 1·30, 95% credible interval 0·92-1·71; log-rank p=0·074). The probability of molnupiravir being superior to placebo (HR>1) was 75·4%, which was less than our threshold of 80%. 73 (81%) of 90 participants in the molnupiravir group and 68 (76%) of 90 participants in the placebo group had at least one adverse event by day 29. One participant in the molnupiravir group and three participants in the placebo group had an adverse event of a Common Terminology Criteria for Adverse Events grade 3 or higher severity. No participants died (due to any cause) during the trial. INTERPRETATION We found molnupiravir to be well tolerated and, although our predefined threshold was not reached, we observed some evidence that molnupiravir has antiviral activity in vaccinated and unvaccinated individuals infected with a broad range of SARS-CoV-2 variants, although this evidence is not conclusive. FUNDING Ridgeback Biotherapeutics, the UK National Institute for Health and Care Research, the Medical Research Council, and the Wellcome Trust.
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Affiliation(s)
- Saye H Khoo
- Pharmacology and Therapeutics, University of Liverpool, Liverpool, UK; Tropical and Infectious Disease Unit, Liverpool University Hospital NHS Foundation Trust, Liverpool, UK.
| | - Richard FitzGerald
- Pharmacology and Therapeutics, University of Liverpool, Liverpool, UK,NIHR Royal Liverpool and Broadgreen Clinical Research Facility, Liverpool University Hospital NHS Foundation Trust, Liverpool, UK
| | - Geoffrey Saunders
- Southampton Clinical Trials Unit, University of Southampton, Southampton, UK
| | - Calley Middleton
- Southampton Clinical Trials Unit, University of Southampton, Southampton, UK
| | - Shazaad Ahmad
- NIHR Manchester Clinical Research Facility, Manchester University NHS Foundation Trust, Manchester, UK
| | - Christopher J Edwards
- Human Development and Health School, University of Southampton, Southampton, UK,NIHR Southampton Clinical Research Facility, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Dennis Hadjiyiannakis
- NIHR Lancashire Clinical Research Facility, Lancashire Teaching Hospitals NHS Foundation Trust, Preston, UK
| | - Lauren Walker
- Pharmacology and Therapeutics, University of Liverpool, Liverpool, UK,NIHR Royal Liverpool and Broadgreen Clinical Research Facility, Liverpool University Hospital NHS Foundation Trust, Liverpool, UK
| | - Rebecca Lyon
- NIHR Royal Liverpool and Broadgreen Clinical Research Facility, Liverpool University Hospital NHS Foundation Trust, Liverpool, UK
| | - Victoria Shaw
- Clinical Directorate, University of Liverpool, Liverpool, UK
| | - Pavel Mozgunov
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - Jimstan Periselneris
- NIHR Kings Clinical Research Facility, King's College Hospital NHS Foundation Trust, London, UK
| | - Christie Woods
- NIHR Royal Liverpool and Broadgreen Clinical Research Facility, Liverpool University Hospital NHS Foundation Trust, Liverpool, UK
| | - Katie Bullock
- Molecular & Clinical Cancer Medicine, University of Liverpool, Liverpool, UK
| | - Colin Hale
- NIHR Royal Liverpool and Broadgreen Clinical Research Facility, Liverpool University Hospital NHS Foundation Trust, Liverpool, UK
| | - Helen Reynolds
- Pharmacology and Therapeutics, University of Liverpool, Liverpool, UK
| | - Nichola Downs
- Southampton Clinical Trials Unit, University of Southampton, Southampton, UK
| | - Sean Ewings
- Southampton Clinical Trials Unit, University of Southampton, Southampton, UK
| | - Amanda Buadi
- NIHR Southampton Clinical Research Facility, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - David Cameron
- NIHR Lancashire Clinical Research Facility, Lancashire Teaching Hospitals NHS Foundation Trust, Preston, UK
| | | | - Emma Knox
- Southampton Clinical Trials Unit, University of Southampton, Southampton, UK
| | - I'ah Donovan-Banfield
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK,National Institute of Health Research Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool, UK
| | - William Greenhalf
- Molecular & Clinical Cancer Medicine, University of Liverpool, Liverpool, UK
| | - Justin Chiong
- Pharmacology and Therapeutics, University of Liverpool, Liverpool, UK
| | | | - Michael Jacobs
- Infectious Diseases, Royal Free London NHS Foundation Trust, London, UK
| | - Josh Northey
- Southampton Clinical Trials Unit, University of Southampton, Southampton, UK
| | | | | | | | - Michelle Tetlow
- Pharmacology and Therapeutics, University of Liverpool, Liverpool, UK
| | - Julian A Hiscox
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK,National Institute of Health Research Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool, UK
| | - Thomas Jaki
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK,Computational Statistics, University of Regensburg, Regensburg, Germany
| | - Thomas Fletcher
- Tropical and Infectious Disease Unit, Liverpool University Hospital NHS Foundation Trust, Liverpool, UK,Clinical Sciences, Liverpool, UK
| | - Gareth Griffiths
- Southampton Clinical Trials Unit, University of Southampton, Southampton, UK
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Mozgunov P, Jaki T, Gounaris I, Goddemeier T, Victor A, Grinberg M. Practical implementation of the partial ordering continual reassessment method in a Phase I combination-schedule dose-finding trial. Stat Med 2022; 41:5789-5809. [PMID: 36428217 PMCID: PMC10100035 DOI: 10.1002/sim.9594] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 07/29/2022] [Accepted: 10/04/2022] [Indexed: 11/27/2022]
Abstract
There is a growing medical interest in combining several agents and optimizing their dosing schedules in a single trial in order to optimize the treatment for patients. Evaluating at doses of several drugs and their scheduling in a single Phase I trial simultaneously possess a number of statistical challenges, and specialized methods to tackle these have been proposed in the literature. However, the uptake of these methods is slow and implementation examples of such advanced methods are still sparse to date. In this work, we share our experience of proposing a model-based partial ordering continual reassessment method (POCRM) design for three-dimensional dose-finding in an oncology trial. In the trial, doses of two agents and the dosing schedule of one of them can be escalated/de-escalated. We provide a step-by-step summary on how the POCRM design was implemented and communicated to the trial team. We proposed an approach to specify toxicity orderings and their a-priori probabilities, and developed a number of visualization tools to communicate the statistical properties of the design. The design evaluation included both a comprehensive simulation study and considerations of the individual trial behavior. The study is now enrolling patients. We hope that sharing our experience of the successful implementation of an advanced design in practice that went through evaluations of several health authorities will facilitate a better uptake of more efficient methods in practice.
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Affiliation(s)
- Pavel Mozgunov
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - Thomas Jaki
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK.,Computational Statistics Group, University of Regensburg, Regensburg, Germany
| | | | - Thomas Goddemeier
- Biostatistics, Epidemiology & Medical Writing, Merck Healthcare KGaA, Darmstadt, Germany
| | - Anja Victor
- Biostatistics, Epidemiology & Medical Writing, Merck Healthcare KGaA, Darmstadt, Germany
| | - Marianna Grinberg
- Biostatistics, Epidemiology & Medical Writing, Merck Healthcare KGaA, Darmstadt, Germany.,Marianna Grinberg, Statistical Sciences and Innovation, UCB, Monheim, Germany
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10
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Paterson LM, Barker D, Cro S, Mozgunov P, Phillips R, Smith C, Nahar L, Paterson S, Lingford-Hughes AR. FORWARDS-1: an adaptive, single-blind, placebo-controlled ascending dose study of acute baclofen on safety parameters in opioid dependence during methadone-maintenance treatment-a pharmacokinetic-pharmacodynamic study. Trials 2022; 23:880. [PMID: 36258248 PMCID: PMC9579625 DOI: 10.1186/s13063-022-06821-9] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 10/05/2022] [Indexed: 11/17/2022] Open
Abstract
Background Treatment of opiate addiction with opiate substitution treatment (e.g. methadone) is beneficial. However, some individuals desire or would benefit from abstinence but there are limited options to attenuate problems with opiate withdrawal. Preclinical and preliminary clinical evidence suggests that the GABA-B agonist, baclofen, has the desired properties to facilitate opiate detoxification and prevent relapse. This study aims to understand whether there are any safety issues in administering baclofen to opioid-dependent individuals receiving methadone. Methods Opiate-dependent individuals (DSM-5 severe opioid use disorder) maintained on methadone will be recruited from addiction services in northwest London (NHS and third sector providers). Participants will be medically healthy with no severe chronic obstructive pulmonary disease or type 2 respiratory failure, no current dependence on other substances (excluding nicotine), no current severe DSM-5 psychiatric disorders, and no contraindications for baclofen or 4800 IU vitamin D (placebo). Eligible participants will be randomised in a 3:1 ratio to receive baclofen or placebo in an adaptive, single-blind, ascending dose design. A Bayesian dose-escalation model will inform the baclofen dose (10, 30, 60, or 90 mg) based on the incidence of ‘dose-limiting toxicity’ (DLT) events and participant-specific methadone dose. A range of respiratory, cardiovascular, and sedative measures including the National Early Warning Score (NEWS2) and Glasgow Coma Scale will determine DLT. On the experimental day, participants will consume their usual daily dose of methadone followed by an acute dose of baclofen or placebo (vitamin D3) ~ 1 h later. Measures including oxygen saturation, transcutaneous CO2, respiratory rate, QTc interval, subjective effects (sedation, drug liking, craving), plasma levels (baclofen, methadone), and adverse events will be obtained using validated questionnaires and examinations periodically for 5 h after dosing. Discussion Study outcomes will determine what dose of baclofen is safe to prescribe to those receiving methadone, to inform a subsequent proof-of-concept trial of the efficacy baclofen to facilitate opiate detoxification. To proceed, the minimum acceptable dose is 30 mg of baclofen in patients receiving ≤ 60 mg/day methadone based on the clinical experience of baclofen’s use in alcoholism and guidelines for the management of opiate dependence. Trial registration Clinicaltrials.gov NCT05161351. Registered on 16 December 2021. Supplementary Information The online version contains supplementary material available at 10.1186/s13063-022-06821-9.
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Affiliation(s)
- L M Paterson
- Division of Psychiatry, Department of Brain Sciences, Imperial College London, London, UK.
| | - D Barker
- Division of Psychiatry, Department of Brain Sciences, Imperial College London, London, UK
| | - S Cro
- Imperial Clinical Trials Unit, Imperial College London, London, UK
| | - P Mozgunov
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - R Phillips
- Imperial Clinical Trials Unit, Imperial College London, London, UK
| | - C Smith
- Imperial Clinical Trials Unit, Imperial College London, London, UK
| | - L Nahar
- Toxicology Unit, Imperial College London, London, UK
| | - S Paterson
- Toxicology Unit, Imperial College London, London, UK
| | - A R Lingford-Hughes
- Division of Psychiatry, Department of Brain Sciences, Imperial College London, London, UK
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11
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Serra A, Mozgunov P, Jaki T, Rigat F. What is the expected benefit of patient-centric clinical development in oncology? J Biopharm Stat 2022; 32:414-426. [PMID: 35848802 DOI: 10.1080/10543406.2022.2065506] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The identification and quantification of predictive biomarkers characterize personalized medicine approaches and patient-centric clinical development. In practice, the sponsor needs evaluating whether biomarker-informed clinical development strategies are more likely to benefit current and future patients. To this end, a simple metric is proposed and assessed here quantifying the expected clinical benefit (ECB) of clinical development programmes. Using simulation scenarios and endpoints relevant to oncology, the ECB of a simple biomarker-informed strategy is shown to be specific and sensitive. Also, the ECB difference is shown to increase in the biomarker-driven incremental efficacy and with the population prevalence of biomarker-positive study participants.
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Affiliation(s)
| | - Pavel Mozgunov
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - Thomas Jaki
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK.,Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
| | - Fabio Rigat
- Janssen Statistics & Decision Sciences, Janssen Pharmaceuticals, UK
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12
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Menzies T, Saint-Hilary G, Mozgunov P. A comparison of various aggregation functions in multi-criteria decision analysis for drug benefit-risk assessment. Stat Methods Med Res 2022; 31:899-916. [PMID: 35044274 PMCID: PMC7612697 DOI: 10.1177/09622802211072512] [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Multi-criteria decision analysis is a quantitative approach to the drug benefit-risk assessment which allows for consistent comparisons by summarising all benefits and risks in a single score. The multi-criteria decision analysis consists of several components, one of which is the utility (or loss) score function that defines how benefits and risks are aggregated into a single quantity. While a linear utility score is one of the most widely used approach in benefit-risk assessment, it is recognised that it can result in counter-intuitive decisions, for example, recommending a treatment with extremely low benefits or high risks. To overcome this problem, alternative approaches to the scores construction, namely, product, multi-linear and Scale Loss Score models, were suggested. However, to date, the majority of arguments concerning the differences implied by these models are heuristic. In this work, we consider four models to calculate the aggregated utility/loss scores and compared their performance in an extensive simulation study over many different scenarios, and in a case study. It is found that the product and Scale Loss Score models provide more intuitive treatment recommendation decisions in the majority of scenarios compared to the linear and multi-linear models, and are more robust to the correlation in the criteria.
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Affiliation(s)
- Tom Menzies
- Clinical Trials Research Unit, Leeds Institute of Clinical Trials
Research, University of Leeds, UK
- Department of Mathematics and Statistics, Lancaster University, UK
| | - Gaelle Saint-Hilary
- Department of Biostatistics, Institut de Recherches Internationales
Servier (IRIS), France
- Dipartimento di Scienze Matematiche (DISMA) Giuseppe Luigi Lagrange,
Politecnico di Torino, Italy
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13
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Walker LE, FitzGerald R, Saunders G, Lyon R, Fisher M, Martin K, Eberhart I, Woods C, Ewings S, Hale C, Rajoli RKR, Else L, Dilly‐Penchala S, Amara A, Lalloo DG, Jacobs M, Pertinez H, Hatchard P, Waugh R, Lawrence M, Johnson L, Fines K, Reynolds H, Rowland T, Crook R, Okenyi E, Byrne K, Mozgunov P, Jaki T, Khoo S, Owen A, Griffiths G, Fletcher TE. An Open Label, Adaptive, Phase 1 Trial of High-Dose Oral Nitazoxanide in Healthy Volunteers: An Antiviral Candidate for SARS-CoV-2. Clin Pharmacol Ther 2022; 111:585-594. [PMID: 34699618 PMCID: PMC8653087 DOI: 10.1002/cpt.2463] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/16/2021] [Indexed: 12/18/2022]
Abstract
Repurposing approved drugs may rapidly establish effective interventions during a public health crisis. This has yielded immunomodulatory treatments for severe coronavirus disease 2019 (COVID-19), but repurposed antivirals have not been successful to date because of redundancy of the target in vivo or suboptimal exposures at studied doses. Nitazoxanide is a US Food and Drug Administration (FDA) approved antiparasitic medicine, that physiologically-based pharmacokinetic (PBPK) modeling has indicated may provide antiviral concentrations across the dosing interval, when repurposed at higher than approved doses. Within the AGILE trial platform (NCT04746183) an open label, adaptive, phase I trial in healthy adult participants was undertaken with high-dose nitazoxanide. Participants received 1,500 mg nitazoxanide orally twice-daily with food for 7 days. Primary outcomes were safety, tolerability, optimum dose, and schedule. Intensive pharmacokinetic (PK) sampling was undertaken day 1 and 5 with minimum concentration (Cmin ) sampling on days 3 and 7. Fourteen healthy participants were enrolled between February 18 and May 11, 2021. All 14 doses were completed by 10 of 14 participants. Nitazoxanide was safe and with no significant adverse events. Moderate gastrointestinal disturbance (loose stools or diarrhea) occurred in 8 participants (57.1%), with urine and sclera discoloration in 12 (85.7%) and 9 (64.3%) participants, respectively, without clinically significant bilirubin elevation. This was self-limiting and resolved upon drug discontinuation. PBPK predictions were confirmed on day 1 but with underprediction at day 5. Median Cmin was above the in vitro target concentration on the first dose and maintained throughout. Nitazoxanide administered at 1,500 mg b.i.d. with food was safe with acceptable tolerability a phase Ib/IIa study is now being initiated in patients with COVID-19.
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Affiliation(s)
- Lauren E. Walker
- University of LiverpoolLiverpoolUK
- Liverpool University Hospitals NHS Foundation TrustLiverpoolUK
| | | | - Geoffrey Saunders
- Southampton Clinical Trials UnitUniversity of SouthamptonSouthamptonUK
| | - Rebecca Lyon
- Liverpool University Hospitals NHS Foundation TrustLiverpoolUK
| | - Michael Fisher
- University of LiverpoolLiverpoolUK
- Liverpool University Hospitals NHS Foundation TrustLiverpoolUK
| | - Karen Martin
- Southampton Clinical Trials UnitUniversity of SouthamptonSouthamptonUK
| | - Izabela Eberhart
- Southampton Clinical Trials UnitUniversity of SouthamptonSouthamptonUK
| | - Christie Woods
- Liverpool University Hospitals NHS Foundation TrustLiverpoolUK
| | - Sean Ewings
- Southampton Clinical Trials UnitUniversity of SouthamptonSouthamptonUK
| | - Colin Hale
- Liverpool University Hospitals NHS Foundation TrustLiverpoolUK
| | | | | | | | | | | | | | | | - Parys Hatchard
- Southampton Clinical Trials UnitUniversity of SouthamptonSouthamptonUK
| | - Robert Waugh
- Southampton Clinical Trials UnitUniversity of SouthamptonSouthamptonUK
| | - Megan Lawrence
- Southampton Clinical Trials UnitUniversity of SouthamptonSouthamptonUK
| | - Lucy Johnson
- Southampton Clinical Trials UnitUniversity of SouthamptonSouthamptonUK
| | - Keira Fines
- Southampton Clinical Trials UnitUniversity of SouthamptonSouthamptonUK
| | | | - Timothy Rowland
- Liverpool University Hospitals NHS Foundation TrustLiverpoolUK
| | - Rebecca Crook
- Liverpool University Hospitals NHS Foundation TrustLiverpoolUK
| | - Emmanuel Okenyi
- Liverpool University Hospitals NHS Foundation TrustLiverpoolUK
| | - Kelly Byrne
- Liverpool School of Tropical MedicineLiverpoolUK
| | - Pavel Mozgunov
- MRC Biostatistics UnitUniversity of CambridgeCambridgeUK
| | - Thomas Jaki
- MRC Biostatistics UnitUniversity of CambridgeCambridgeUK
| | | | | | - Gareth Griffiths
- Southampton Clinical Trials UnitUniversity of SouthamptonSouthamptonUK
| | - Thomas E. Fletcher
- Liverpool University Hospitals NHS Foundation TrustLiverpoolUK
- Liverpool School of Tropical MedicineLiverpoolUK
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14
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Ewings S, Saunders G, Jaki T, Mozgunov P. Practical recommendations for implementing a Bayesian adaptive phase I design during a pandemic. BMC Med Res Methodol 2022; 22:25. [PMID: 35057758 PMCID: PMC8771176 DOI: 10.1186/s12874-022-01512-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/06/2022] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Modern designs for dose-finding studies (e.g., model-based designs such as continual reassessment method) have been shown to substantially improve the ability to determine a suitable dose for efficacy testing when compared to traditional designs such as the 3 + 3 design. However, implementing such designs requires time and specialist knowledge. METHODS We present a practical approach to developing a model-based design to help support uptake of these methods; in particular, we lay out how to derive the necessary parameters and who should input, and when, to these decisions. Designing a model-based, dose-finding trial is demonstrated using a treatment within the AGILE platform trial, a phase I/II adaptive design for novel COVID-19 treatments. RESULTS We present discussion of the practical delivery of AGILE, covering what information was found to support principled decision making by the Safety Review Committee, and what could be contained within a statistical analysis plan. We also discuss additional challenges we encountered in the study and discuss more generally what (unplanned) adaptations may be acceptable (or not) in studies using model-based designs. CONCLUSIONS This example demonstrates both how to design and deliver an adaptive dose-finding trial in order to support uptake of these methods.
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Affiliation(s)
- Sean Ewings
- Southampton Clinical Trials Unit, University of Southampton, Mailpoint 131, Southampton General Hospital, Tremona Road, Southampton, SO16, UK.
| | - Geoff Saunders
- Southampton Clinical Trials Unit, University of Southampton, Mailpoint 131, Southampton General Hospital, Tremona Road, Southampton, SO16, UK
| | - Thomas Jaki
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
- Department of Mathematics and Statistics, Lancaster University, University of Lancaster, Lancaster, UK
| | - Pavel Mozgunov
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
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15
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Serra A, Mozgunov P, Jaki T. An order restricted multi-arm multi-stage clinical trial design. Stat Med 2022; 41:1613-1626. [PMID: 35048391 PMCID: PMC7612618 DOI: 10.1002/sim.9314] [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] [Received: 10/05/2021] [Revised: 12/06/2021] [Accepted: 12/20/2021] [Indexed: 11/09/2022]
Abstract
One family of designs that can noticeably improve efficiency in later stages of drug development are multi-arm multi-stage (MAMS) designs. They allow several arms to be studied concurrently and gain efficiency by dropping poorly performing treatment arms during the trial as well as by allowing to stop early for benefit. Conventional MAMS designs were developed for the setting, in which treatment arms are independent and hence can be inefficient when an order in the effects of the arms can be assumed (eg, when considering different treatment durations or different doses). In this work, we extend the MAMS framework to incorporate the order of treatment effects when no parametric dose-response or duration-response model is assumed. The design can identify all promising treatments with high probability. We show that the design provides strong control of the family-wise error rate and illustrate the design in a study of symptomatic asthma. Via simulations we show that the inclusion of the ordering information leads to better decision-making compared to a fixed sample and a MAMS design. Specifically, in the considered settings, reductions in sample size of around 15% were achieved in comparison to a conventional MAMS design.
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Affiliation(s)
| | - Pavel Mozgunov
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - Thomas Jaki
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK.,Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
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16
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Mozgunov P, Cro S, Lingford-Hughes A, Paterson LM, Jaki T. A dose-finding design for dual-agent trials with patient-specific doses for one agent with application to an opiate detoxification trial. Pharm Stat 2021; 21:476-495. [PMID: 34891221 PMCID: PMC7612599 DOI: 10.1002/pst.2181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 10/06/2020] [Revised: 08/31/2021] [Accepted: 11/21/2021] [Indexed: 11/08/2022]
Abstract
There is a growing interest in early phase dose-finding clinical trials studying combinations of several treatments. While the majority of dose finding designs for such setting were proposed for oncology trials, the corresponding designs are also essential in other therapeutic areas. Furthermore, there is increased recognition of recommending the patient-specific doses/combinations, rather than a single target one that would be recommended to all patients in later phases regardless of their characteristics. In this paper, we propose a dose-finding design for a dual-agent combination trial motivated by an opiate detoxification trial. The distinguishing feature of the trial is that the (continuous) dose of one compound is defined externally by the clinicians and is individual for every patient. The objective of the trial is to define the dosing function that for each patient would recommend the optimal dosage of the second compound. Via a simulation study, we have found that the proposed design results in high accuracy of individual dose recommendation and is robust to the model misspecification and assumptions on the distribution of externally defined doses.
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Affiliation(s)
- Pavel Mozgunov
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - Suzie Cro
- Imperial Clinical Trials Unit, School of Public Health, Imperial College, London, UK
| | - Anne Lingford-Hughes
- Division of Psychiatry, Department of Brain Sciences, Imperial College, London, UK
| | - Louise M Paterson
- Division of Psychiatry, Department of Brain Sciences, Imperial College, London, UK
| | - Thomas Jaki
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK.,Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
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17
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Khoo SH, Fitzgerald R, Fletcher T, Ewings S, Jaki T, Lyon R, Downs N, Walker L, Tansley-Hancock O, Greenhalf W, Woods C, Reynolds H, Marwood E, Mozgunov P, Adams E, Bullock K, Holman W, Bula MD, Gibney JL, Saunders G, Corkhill A, Hale C, Thorne K, Chiong J, Condie S, Pertinez H, Painter W, Wrixon E, Johnson L, Yeats S, Mallard K, Radford M, Fines K, Shaw V, Owen A, Lalloo DG, Jacobs M, Griffiths G. Optimal dose and safety of molnupiravir in patients with early SARS-CoV-2: a Phase I, open-label, dose-escalating, randomized controlled study. J Antimicrob Chemother 2021; 76:3286-3295. [PMID: 34450619 PMCID: PMC8598307 DOI: 10.1093/jac/dkab318] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/04/2021] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES AGILE is a Phase Ib/IIa platform for rapidly evaluating COVID-19 treatments. In this trial (NCT04746183) we evaluated the safety and optimal dose of molnupiravir in participants with early symptomatic infection. METHODS We undertook a dose-escalating, open-label, randomized-controlled (standard-of-care) Bayesian adaptive Phase I trial at the Royal Liverpool and Broadgreen Clinical Research Facility. Participants (adult outpatients with PCR-confirmed SARS-CoV-2 infection within 5 days of symptom onset) were randomized 2:1 in groups of 6 participants to 300, 600 and 800 mg doses of molnupiravir orally, twice daily for 5 days or control. A dose was judged unsafe if the probability of 30% or greater dose-limiting toxicity (the primary outcome) over controls was 25% or greater. Secondary outcomes included safety, clinical progression, pharmacokinetics and virological responses. RESULTS Of 103 participants screened, 18 participants were enrolled between 17 July and 30 October 2020. Molnupiravir was well tolerated at 300, 600 and 800 mg doses with no serious or severe adverse events. Overall, 4 of 4 (100%), 4 of 4 (100%) and 1 of 4 (25%) of the participants receiving 300, 600 and 800 mg molnupiravir, respectively, and 5 of 6 (83%) controls, had at least one adverse event, all of which were mild (≤grade 2). The probability of ≥30% excess toxicity over controls at 800 mg was estimated at 0.9%. CONCLUSIONS Molnupiravir was safe and well tolerated; a dose of 800 mg twice daily for 5 days was recommended for Phase II evaluation.
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Affiliation(s)
- Saye H Khoo
- University of Liverpool, 70 Pembroke Place, Liverpool, UK.,Liverpool University Hospital NHS Foundation Trust, Prescot Road, Liverpool, UK
| | - Richard Fitzgerald
- Liverpool University Hospital NHS Foundation Trust, Prescot Road, Liverpool, UK
| | - Thomas Fletcher
- Liverpool University Hospital NHS Foundation Trust, Prescot Road, Liverpool, UK.,Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Sean Ewings
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
| | - Thomas Jaki
- University of Lancaster, Bailrigg, Lancaster, UK.,MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - Rebecca Lyon
- Liverpool University Hospital NHS Foundation Trust, Prescot Road, Liverpool, UK
| | - Nichola Downs
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
| | - Lauren Walker
- University of Liverpool, 70 Pembroke Place, Liverpool, UK.,Liverpool University Hospital NHS Foundation Trust, Prescot Road, Liverpool, UK
| | - Olana Tansley-Hancock
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
| | | | - Christie Woods
- Liverpool University Hospital NHS Foundation Trust, Prescot Road, Liverpool, UK
| | - Helen Reynolds
- University of Liverpool, 70 Pembroke Place, Liverpool, UK
| | - Ellice Marwood
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
| | | | - Emily Adams
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Katie Bullock
- University of Liverpool, 70 Pembroke Place, Liverpool, UK
| | - Wayne Holman
- Ridgeback Biotherapeutics, 3480 Main Highway, Miami, FL, USA
| | - Marcin D Bula
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
| | - Jennifer L Gibney
- Liverpool University Hospital NHS Foundation Trust, Prescot Road, Liverpool, UK
| | - Geoffrey Saunders
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
| | - Andrea Corkhill
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
| | - Colin Hale
- Liverpool University Hospital NHS Foundation Trust, Prescot Road, Liverpool, UK
| | - Kerensa Thorne
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
| | - Justin Chiong
- University of Liverpool, 70 Pembroke Place, Liverpool, UK
| | - Susannah Condie
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
| | - Henry Pertinez
- University of Liverpool, 70 Pembroke Place, Liverpool, UK
| | - Wendy Painter
- Ridgeback Biotherapeutics, 3480 Main Highway, Miami, FL, USA
| | - Emma Wrixon
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
| | - Lucy Johnson
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
| | - Sara Yeats
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
| | - Kim Mallard
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
| | - Mike Radford
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
| | - Keira Fines
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
| | - Victoria Shaw
- University of Liverpool, 70 Pembroke Place, Liverpool, UK
| | - Andrew Owen
- University of Liverpool, 70 Pembroke Place, Liverpool, UK
| | - David G Lalloo
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Michael Jacobs
- Royal Free London NHS Foundation Trust, Pond Street, London, UK
| | - Gareth Griffiths
- Southampton Clinical Trials Unit, University of Southampton, Tremona Road, Southampton, UK
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18
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Griffiths GO, FitzGerald R, Jaki T, Corkhill A, Reynolds H, Ewings S, Condie S, Tilt E, Johnson L, Radford M, Simpson C, Saunders G, Yeats S, Mozgunov P, Tansley-Hancock O, Martin K, Downs N, Eberhart I, Martin JWB, Goncalves C, Song A, Fletcher T, Byrne K, Lalloo DG, Owen A, Jacobs M, Walker L, Lyon R, Woods C, Gibney J, Chiong J, Chandiwana N, Jacob S, Lamorde M, Orrell C, Pirmohamed M, Khoo S. AGILE: a seamless phase I/IIa platform for the rapid evaluation of candidates for COVID-19 treatment: an update to the structured summary of a study protocol for a randomised platform trial letter. Trials 2021; 22:487. [PMID: 34311777 PMCID: PMC8311065 DOI: 10.1186/s13063-021-05458-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [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: 03/29/2021] [Accepted: 07/14/2021] [Indexed: 12/15/2022] Open
Abstract
Background There is an urgent unmet clinical need for the identification of novel therapeutics for the treatment of COVID-19. A number of COVID-19 late phase trial platforms have been developed to investigate (often repurposed) drugs both in the UK and globally (e.g. RECOVERY led by the University of Oxford and SOLIDARITY led by WHO). There is a pressing need to investigate novel candidates within early phase trial platforms, from which promising candidates can feed into established later phase platforms. AGILE grew from a UK-wide collaboration to undertake early stage clinical evaluation of candidates for SARS-CoV-2 infection to accelerate national and global healthcare interventions. Methods/design AGILE is a seamless phase I/IIa platform study to establish the optimum dose, determine the activity and safety of each candidate and recommend whether it should be evaluated further. Each candidate is evaluated in its own trial, either as an open label single arm healthy volunteer study or in patients, randomising between candidate and control usually in a 2:1 allocation in favour of the candidate. Each dose is assessed sequentially for safety usually in cohorts of 6 patients. Once a phase II dose has been identified, efficacy is assessed by seamlessly expanding into a larger cohort. AGILE is completely flexible in that the core design in the master protocol can be adapted for each candidate based on prior knowledge of the candidate (i.e. population, primary endpoint and sample size can be amended). This information is detailed in each candidate specific trial protocol of the master protocol. Discussion Few approved treatments for COVID-19 are available such as dexamethasone, remdesivir and tocilizumab in hospitalised patients. The AGILE platform aims to rapidly identify new efficacious and safe treatments to help end the current global COVID-19 pandemic. We currently have three candidate specific trials within this platform study that are open to recruitment. Trial registration EudraCT Number: 2020-001860-27 14 March 2020 ClinicalTrials.gov Identifier: NCT04746183 19 February 2021 ISRCTN reference: 27106947 Supplementary Information The online version contains supplementary material available at 10.1186/s13063-021-05458-4.
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Affiliation(s)
- Gareth O Griffiths
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK.
| | - Richard FitzGerald
- NIHR Royal Liverpool and Broadgreen CRF, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Thomas Jaki
- Lancaster University, Lancaster UK and MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - Andrea Corkhill
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | | | - Sean Ewings
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | - Susannah Condie
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | - Emma Tilt
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | - Lucy Johnson
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | - Mike Radford
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | - Catherine Simpson
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | - Geoffrey Saunders
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | - Sara Yeats
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | - Pavel Mozgunov
- Lancaster University, Lancaster UK and MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - Olana Tansley-Hancock
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | - Karen Martin
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | - Nichola Downs
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | - Izabela Eberhart
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | - Jonathan W B Martin
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | - Cristiana Goncalves
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | - Anna Song
- Southampton Clinical Trials Unit, University of Southampton, Southampton, Hampshire, UK
| | - Tom Fletcher
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Kelly Byrne
- Liverpool School of Tropical Medicine, Liverpool, UK
| | | | | | | | - Lauren Walker
- NIHR Royal Liverpool and Broadgreen CRF, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Rebecca Lyon
- NIHR Royal Liverpool and Broadgreen CRF, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Christie Woods
- NIHR Royal Liverpool and Broadgreen CRF, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Jennifer Gibney
- NIHR Royal Liverpool and Broadgreen CRF, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Justin Chiong
- NIHR Royal Liverpool and Broadgreen CRF, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK.,University of Liverpool, Liverpool, UK
| | | | - Shevin Jacob
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Mohammed Lamorde
- Infectious Diseases Institute, Makerere University, Kampala, Uganda
| | - Catherine Orrell
- Desmond Tutu Health Foundation, University of Cape Town, Cape Town, South Africa
| | - Munir Pirmohamed
- NIHR Royal Liverpool and Broadgreen CRF, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK.,University of Liverpool, Liverpool, UK
| | - Saye Khoo
- NIHR Royal Liverpool and Broadgreen CRF, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK.,University of Liverpool, Liverpool, UK
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19
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Mozgunov P, Paoletti X, Jaki T. A benchmark for dose-finding studies with unknown ordering. Biostatistics 2021; 23:721-737. [PMID: 33409536 PMCID: PMC9291639 DOI: 10.1093/biostatistics/kxaa054] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [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: 04/16/2020] [Revised: 09/25/2020] [Accepted: 11/09/2020] [Indexed: 01/31/2023] Open
Abstract
An important tool to evaluate the performance of a dose-finding design is the nonparametric optimal benchmark that provides an upper bound on the performance of a design under a given scenario. A fundamental assumption of the benchmark is that the investigator can arrange doses in a monotonically increasing toxicity order. While the benchmark can be still applied to combination studies in which not all dose combinations can be ordered, it does not account for the uncertainty in the ordering. In this article, we propose a generalization of the benchmark that accounts for this uncertainty and, as a result, provides a sharper upper bound on the performance. The benchmark assesses how probable the occurrence of each ordering is, given the complete information about each patient. The proposed approach can be applied to trials with an arbitrary number of endpoints with discrete or continuous distributions. We illustrate the utility of the benchmark using recently proposed dose-finding designs for Phase I combination trials with a binary toxicity endpoint and Phase I/II combination trials with binary toxicity and continuous efficacy.
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Affiliation(s)
- Pavel Mozgunov
- Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
| | - Xavier Paoletti
- Université Versailles St Quentin & INSERM U900 STAMPM, Institut Curie, Paris, France
| | - Thomas Jaki
- Department of Mathematics and Statistics, Lancaster University, Lancaster, UK and MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
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20
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Burnett T, Mozgunov P, Pallmann P, Villar SS, Wheeler GM, Jaki T. Adding flexibility to clinical trial designs: an example-based guide to the practical use of adaptive designs. BMC Med 2020; 18:352. [PMID: 33208155 PMCID: PMC7677786 DOI: 10.1186/s12916-020-01808-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 10/07/2020] [Indexed: 12/18/2022] Open
Abstract
Adaptive designs for clinical trials permit alterations to a study in response to accumulating data in order to make trials more flexible, ethical, and efficient. These benefits are achieved while preserving the integrity and validity of the trial, through the pre-specification and proper adjustment for the possible alterations during the course of the trial. Despite much research in the statistical literature highlighting the potential advantages of adaptive designs over traditional fixed designs, the uptake of such methods in clinical research has been slow. One major reason for this is that different adaptations to trial designs, as well as their advantages and limitations, remain unfamiliar to large parts of the clinical community. The aim of this paper is to clarify where adaptive designs can be used to address specific questions of scientific interest; we introduce the main features of adaptive designs and commonly used terminology, highlighting their utility and pitfalls, and illustrate their use through case studies of adaptive trials ranging from early-phase dose escalation to confirmatory phase III studies.
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Affiliation(s)
- Thomas Burnett
- Department of Mathematics and Statistics, Lancaster University, Fylde College, Lancaster, LA1 4YF UK
| | - Pavel Mozgunov
- Department of Mathematics and Statistics, Lancaster University, Fylde College, Lancaster, LA1 4YF UK
| | - Philip Pallmann
- Centre for Trials Research, College of Biomedical & Life Sciences, Cardiff University, Cardiff, UK
| | - Sofia S. Villar
- MRC Biostatistics Unit, University of Cambridge School of Clinical Medicine, Cambridge Institute of Public Health, Forvie Site, Robinson Way, Cambridge Biomedical Campus, Cambridge, CB2 0SR UK
| | - Graham M. Wheeler
- Cancer Research UK & UCL Cancer Trials Centre, University College London, 90 Tottenham Court Road, London, W1T 4TJ UK
| | - Thomas Jaki
- Department of Mathematics and Statistics, Lancaster University, Fylde College, Lancaster, LA1 4YF UK
- MRC Biostatistics Unit, University of Cambridge School of Clinical Medicine, Cambridge Institute of Public Health, Forvie Site, Robinson Way, Cambridge Biomedical Campus, Cambridge, CB2 0SR UK
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21
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Affiliation(s)
| | - Thomas Jaki
- Lancaster University and University of Cambridge UK
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22
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Stallard N, Hampson L, Benda N, Brannath W, Burnett T, Friede T, Kimani PK, Koenig F, Krisam J, Mozgunov P, Posch M, Wason J, Wassmer G, Whitehead J, Williamson SF, Zohar S, Jaki T. Efficient Adaptive Designs for Clinical Trials of Interventions for COVID-19. Stat Biopharm Res 2020; 12:483-497. [PMID: 34191981 PMCID: PMC8011600 DOI: 10.1080/19466315.2020.1790415] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/23/2020] [Accepted: 06/24/2020] [Indexed: 02/06/2023]
Abstract
The COVID-19 pandemic has led to an unprecedented response in terms of clinical research activity. An important part of this research has been focused on randomized controlled clinical trials to evaluate potential therapies for COVID-19. The results from this research need to be obtained as rapidly as possible. This presents a number of challenges associated with considerable uncertainty over the natural history of the disease and the number and characteristics of patients affected, and the emergence of new potential therapies. These challenges make adaptive designs for clinical trials a particularly attractive option. Such designs allow a trial to be modified on the basis of interim analysis data or stopped as soon as sufficiently strong evidence has been observed to answer the research question, without compromising the trial's scientific validity or integrity. In this article, we describe some of the adaptive design approaches that are available and discuss particular issues and challenges associated with their use in the pandemic setting. Our discussion is illustrated by details of four ongoing COVID-19 trials that have used adaptive designs.
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Affiliation(s)
- Nigel Stallard
- Statistics and Epidemiology, Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Lisa Hampson
- Advanced Methodology and Data Science, Novartis Pharma AG, Basel, Switzerland
| | - Norbert Benda
- The Federal Institute for Drugs and Medical Devices (BfArM), Bonn, Germany
| | - Werner Brannath
- Institute for Statistics, University of Bremen, Bremen, Germany
| | - Thomas Burnett
- Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
| | - Tim Friede
- Department of Medical Statistics, University Medical Center Göttingen, Göttingen, Germany
| | - Peter K. Kimani
- Statistics and Epidemiology, Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Franz Koenig
- Section for Medical Statistics, CeMSIIS, Medical University of Vienna, Vienna, Austria
| | - Johannes Krisam
- Institute of Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany
| | - Pavel Mozgunov
- Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
| | - Martin Posch
- Section for Medical Statistics, CeMSIIS, Medical University of Vienna, Vienna, Austria
| | - James Wason
- Population Health Sciences Institute, Newcastle University, Newcastle upon Tyne, UK
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | | | - John Whitehead
- Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
| | - S. Faye Williamson
- Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
| | - Sarah Zohar
- INSERM, Centre de Recherche des Cordeliers, Sorbonne Université, Université de Paris, Paris, France
| | - Thomas Jaki
- Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
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23
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Abbas R, Rossoni C, Jaki T, Paoletti X, Mozgunov P. A comparison of phase I dose-finding designs in clinical trials with monotonicity assumption violation. Clin Trials 2020; 17:522-534. [PMID: 32631095 DOI: 10.1177/1740774520932130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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: 11/16/2022]
Abstract
BACKGROUND/AIMS In oncology, new combined treatments make it difficult to order dose levels according to monotonically increasing toxicity. New flexible dose-finding designs that take into account uncertainty in dose levels ordering were compared with classical designs through simulations in the setting of the monotonicity assumption violation. We give recommendations for the choice of dose-finding design. METHODS Motivated by a clinical trial for patients with high-risk neuroblastoma, we considered designs that require a monotonicity assumption, the Bayesian Continual Reassessment Method, the modified Toxicity Probability Interval, the Bayesian Optimal Interval design, and designs that relax monotonicity assumption, the Bayesian Partial Ordering Continual Reassessment Method and the No Monotonicity Assumption design. We considered 15 scenarios including monotonic and non-monotonic dose-toxicity relationships among six dose levels. RESULTS The No Monotonicity Assumption and Partial Ordering Continual Reassessment Method designs were robust to the violation of the monotonicity assumption. Under non-monotonic scenarios, the No Monotonicity Assumption design selected the correct dose level more often than alternative methods on average. Under the majority of monotonic scenarios, the Partial Ordering Continual Reassessment Method selected the correct dose level more often than the No Monotonicity Assumption design. Other designs were impacted by the violation of the monotonicity assumption with a proportion of correct selections below 20% in most scenarios. Under monotonic scenarios, the highest proportions of correct selections were achieved using the Continual Reassessment Method and the Bayesian Optimal Interval design (between 52.8% and 73.1%). The costs of relaxing the monotonicity assumption by the No Monotonicity Assumption design and Partial Ordering Continual Reassessment Method were decreases in the proportions of correct selections under monotonic scenarios ranging from 5.3% to 20.7% and from 1.4% to 16.1%, respectively, compared with the best performing design and were higher proportions of patients allocated to toxic dose levels during the trial. CONCLUSIONS Innovative oncology treatments may no longer follow monotonic dose levels ordering which makes standard phase I methods fail. In such a setting, appropriate designs, as the No Monotonicity Assumption or Partial Ordering Continual Reassessment Method designs, should be used to safely determine recommended for phase II dose.
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Affiliation(s)
- Rachid Abbas
- ONCOSTAT Team CESP INSERM U1018, Univ. Paris-Saclay and Biostatistics and Epidemiology department, Gustave Roussy Cancer Center, Villejuif, France
| | - Caroline Rossoni
- ONCOSTAT Team CESP INSERM U1018, Univ. Paris-Saclay and Biostatistics and Epidemiology department, Gustave Roussy Cancer Center, Villejuif, France
| | - Thomas Jaki
- Department of Mathematics and Statistics, Lancaster University, Lancaster, UK.,MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - Xavier Paoletti
- Université Versailles St Quentin & INSERM U900 STAMPM, Institut Curie, Paris, France
| | - Pavel Mozgunov
- Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
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24
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Mozgunov P, Jaki T, Paoletti X. Using a dose-finding benchmark to quantify the loss incurred by dichotomization in Phase II dose-ranging studies. Biom J 2020; 62:1717-1729. [PMID: 32529689 DOI: 10.1002/bimj.201900332] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 02/20/2020] [Accepted: 04/05/2020] [Indexed: 11/07/2022]
Abstract
While there is recognition that more informative clinical endpoints can support better decision-making in clinical trials, it remains a common practice to categorize endpoints originally measured on a continuous scale. The primary motivation for this categorization (and most commonly dichotomization) is the simplicity of the analysis. There is, however, a long argument that this simplicity can come at a high cost. Specifically, larger sample sizes are needed to achieve the same level of accuracy when using a dichotomized outcome instead of the original continuous endpoint. The degree of "loss of information" has been studied in the contexts of parallel-group designs and two-stage Phase II trials. Limited attention, however, has been given to the quantification of the associated losses in dose-ranging trials. In this work, we propose an approach to estimate the associated losses in Phase II dose-ranging trials that is free of the actual dose-ranging design used and depends on the clinical setting only. The approach uses the notion of a nonparametric optimal benchmark for dose-finding trials, an evaluation tool that facilitates the assessment of a dose-finding design by providing an upper bound on its performance under a given scenario in terms of the probability of the target dose selection. After demonstrating how the benchmark can be applied to Phase II dose-ranging trials, we use it to quantify the dichotomization losses. Using parameters from real clinical trials in various therapeutic areas, it is found that the ratio of sample sizes needed to obtain the same precision using continuous and binary (dichotomized) endpoints varies between 70% and 75% under the majority of scenarios but can drop to 50% in some cases.
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Affiliation(s)
- Pavel Mozgunov
- Medical and Pharmaceutical Statistics Research Unit, Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
| | - Thomas Jaki
- Medical and Pharmaceutical Statistics Research Unit, Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
| | - Xavier Paoletti
- Service de Biostatistique et d'Epidemiologie & CESP OncoStat, INSERM, Institut Gustave Roussy, UVSQ, Villejuif, France.,Institute Curie, Paris, France
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25
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Abstract
In oncology, there is a growing number of therapies given in combination. Recently, several dose-finding designs for Phase I dose-escalation trials for combinations were proposed. The majority of novel designs use a pre-specified parametric model restricting the search of the target combination to a surface of a particular form. In this work, we propose a novel model-free design for combination studies, which is based on the assumption of monotonicity within each agent only. Specifically, we parametrise the ratios between each neighbouring combination by independent Beta distributions. As a result, the design does not require the specification of any particular parametric model or knowledge about increasing orderings of toxicity. We compare the performance of the proposed design to the model-based continual reassessment method for partial ordering and to another model-free alternative, the product of independent beta design. In an extensive simulation study, we show that the proposed design leads to comparable or better proportions of correct selections of the target combination while leading to the same or fewer average number of toxic responses in a trial.
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Affiliation(s)
- Pavel Mozgunov
- Medical and Pharmaceutical Statistics Research Unit, Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
| | - Mauro Gasparini
- Dipartimento di Scienze Matematiche (DISMA) Giuseppe Luigi Lagrange, Politecnico di Torino, Torino, Italy
| | - Thomas Jaki
- Medical and Pharmaceutical Statistics Research Unit, Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
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26
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Mozgunov P, Jaki T. Improving safety of the continual reassessment method via a modified allocation rule. Stat Med 2020; 39:906-922. [PMID: 31859399 PMCID: PMC7064916 DOI: 10.1002/sim.8450] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/26/2019] [Accepted: 11/29/2019] [Indexed: 01/20/2023]
Abstract
This article proposes a novel criterion for the allocation of patients in phase I dose-escalation clinical trials, aiming to find the maximum tolerated dose (MTD). Conventionally, using a model-based approach, the next patient is allocated to the dose with the toxicity estimate closest (in terms of the absolute or squared distance) to the maximum acceptable toxicity. This approach, however, ignores the uncertainty in point estimates and ethical concerns of assigning a lot of patients to overly toxic doses. In fact, balancing the trade-off between how accurately the MTD can be estimated and how many patients would experience adverse events is one of the primary challenges in phase I studies. Motivated by recent discussions in the theory of estimation in restricted parameter spaces, we propose a criterion that allows to balance these explicitly. The criterion requires a specification of one additional parameter only that has a simple and intuitive interpretation. We incorporate the proposed criterion into the one-parameter Bayesian continual reassessment method and show, using simulations, that it can result in similar accuracy on average as the original design, but with fewer toxic responses on average. A comparison with other model-based dose-escalation designs, such as escalation with overdose control and its modifications, demonstrates that the proposed design can result in either the same mean accuracy as alternatives but fewer toxic responses or in a higher mean accuracy but the same number of toxic responses. Therefore, the proposed design can provide a better trade-off between the accuracy and the number of patients experiencing adverse events, making the design a more ethical alternative over some of the existing methods for phase I trials.
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Affiliation(s)
- Pavel Mozgunov
- Department of Mathematics and StatisticsLancaster UniversityLancasterUK
| | - Thomas Jaki
- Department of Mathematics and StatisticsLancaster UniversityLancasterUK
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27
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Mozgunov P, Jaki T. A flexible design for advanced Phase I/II clinical trials with continuous efficacy endpoints. Biom J 2019; 61:1477-1492. [PMID: 31298770 PMCID: PMC6899762 DOI: 10.1002/bimj.201800313] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 01/23/2019] [Accepted: 06/04/2019] [Indexed: 11/24/2022]
Abstract
There is growing interest in integrated Phase I/II oncology clinical trials involving molecularly targeted agents (MTA). One of the main challenges of these trials are nontrivial dose-efficacy relationships and administration of MTAs in combination with other agents. While some designs were recently proposed for such Phase I/II trials, the majority of them consider the case of binary toxicity and efficacy endpoints only. At the same time, a continuous efficacy endpoint can carry more information about the agent's mechanism of action, but corresponding designs have received very limited attention in the literature. In this work, an extension of a recently developed information-theoretic design for the case of a continuous efficacy endpoint is proposed. The design transforms the continuous outcome using the logistic transformation and uses an information-theoretic argument to govern selection during the trial. The performance of the design is investigated in settings of single-agent and dual-agent trials. It is found that the novel design leads to substantial improvements in operating characteristics compared to a model-based alternative under scenarios with nonmonotonic dose/combination-efficacy relationships. The robustness of the design to missing/delayed efficacy responses and to the correlation in toxicity and efficacy endpoints is also investigated.
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Affiliation(s)
- Pavel Mozgunov
- Medical and Pharmaceutical Statistics Research UnitDepartment of Mathematics and StatisticsLancaster UniversityLancasterUK
| | - Thomas Jaki
- Medical and Pharmaceutical Statistics Research UnitDepartment of Mathematics and StatisticsLancaster UniversityLancasterUK
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28
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Abstract
Quantitative methods have been proposed to assess and compare the benefit-risk balance of treatments. Among them, multicriteria decision analysis (MCDA) is a popular decision tool as it permits to summarise the benefits and the risks of a drug in a single utility score, accounting for the preferences of the decision-makers. However, the utility score is often derived using a linear model which might lead to counter-intuitive conclusions; for example, drugs with no benefit or extreme risk could be recommended. Moreover, it assumes that the relative importance of benefits against risks is constant for all levels of benefit or risk, which might not hold for all drugs. We propose Scale Loss Score (SLoS) as a new tool for the benefit-risk assessment, which offers the same advantages as the linear multicriteria decision analysis utility score but has, in addition, desirable properties permitting to avoid recommendations of non-effective or extremely unsafe treatments, and to tolerate larger increases in risk for a given increase in benefit when the amount of benefit is small than when it is high. We present an application to a real case study on telithromycin in Community Acquired Pneumonia and Acute Bacterial Sinusitis, and we investigated the patterns of behaviour of Scale Loss Score, as compared to the linear multicriteria decision analysis, in a comprehensive simulation study.
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Affiliation(s)
- Gaelle Saint-Hilary
- Dipartimento di Scienze Matematiche
(DISMA) Giuseppe Luigi Lagrange, Politecnico di Torino, Torino, Italy
| | - Veronique Robert
- Department of Biostatistics, Institut de
Recherches Internationales Servier (IRIS), Suresnes, France
| | - Mauro Gasparini
- Dipartimento di Scienze Matematiche
(DISMA) Giuseppe Luigi Lagrange, Politecnico di Torino, Torino, Italy
| | - Thomas Jaki
- Medical and Pharmaceutical Statistics
Research Unit,
Department
of Mathematics and Statistics, Lancaster
University, Lancaster, UK
| | - Pavel Mozgunov
- Medical and Pharmaceutical Statistics
Research Unit,
Department
of Mathematics and Statistics, Lancaster
University, Lancaster, UK
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29
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Abstract
Squared error loss remains the most commonly used loss function for constructing a Bayes estimator of the parameter of interest. However, it can lead to suboptimal solutions when a parameter is defined on a restricted space. It can also be an inappropriate choice in the context when an extreme overestimation and/or underestimation results in severe consequences and a more conservative estimator is preferred. We advocate a class of loss functions for parameters defined on restricted spaces which infinitely penalize boundary decisions like the squared error loss does on the real line. We also recall several properties of loss functions such as symmetry, convexity and invariance. We propose generalizations of the squared error loss function for parameters defined on the positive real line and on an interval. We provide explicit solutions for corresponding Bayes estimators and discuss multivariate extensions. Four well-known Bayesian estimation problems are used to demonstrate inferential benefits the novel Bayes estimators can provide in the context of restricted estimation.
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Affiliation(s)
- P. Mozgunov
- Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
| | - T. Jaki
- Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
| | - M. Gasparini
- Dipartimento di Scienze Matematiche, Politecnico di Torino, Turin, Italy
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30
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Mozgunov P, Jaki T. An information theoretic phase I-II design for molecularly targeted agents that does not require an assumption of monotonicity. J R Stat Soc Ser C Appl Stat 2019; 68:347-367. [PMID: 31007292 PMCID: PMC6472641 DOI: 10.1111/rssc.12293] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
For many years phase I and phase II clinical trials have been conducted separately, but there has been a recent shift to combine these phases. Although a variety of phase I-II model-based designs for cytotoxic agents have been proposed in the literature, methods for molecularly targeted agents (TAs) are just starting to develop. The main challenge of the TA setting is the unknown dose-efficacy relationship that can have either an increasing, plateau or umbrella shape. To capture these, approaches with more parameters are needed or, alternatively, more orderings are required to account for the uncertainty in the dose-efficacy relationship. As a result, designs for more complex clinical trials, e.g. trials looking at schedules of a combination treatment involving TAs, have not been extensively studied yet. We propose a novel regimen finding design which is based on a derived efficacy-toxicity trade-off function. Because of its special properties, an accurate regimen selection can be achieved without any parametric or monotonicity assumptions. We illustrate how this design can be applied in the context of a complex combination-schedule clinical trial. We discuss practical and ethical issues such as coherence, delayed and missing efficacy responses, safety and futility constraints.
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31
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Abstract
This work considers Phase I cancer dual-agent dose-escalation clinical trials in which one of the compounds is an immunotherapy. The distinguishing feature of trials considered is that the dose of one agent, referred to as a standard of care, is fixed and another agent is dose-escalated. Conventionally, the goal of a Phase I trial is to find the maximum tolerated combination (MTC). However, in trials involving an immunotherapy, it is also essential to test whether a difference in toxicities associated with the MTC and the standard of care alone is present. This information can give useful insights about the interaction of the compounds and can provide a quantification of the additional toxicity burden and therapeutic index. We show that both, testing for difference between toxicity risks and selecting MTC can be achieved using a Bayesian model-based dose-escalation design with two modifications. Firstly, the standard of care administrated alone is included in the trial as a control arm and each patient is randomized between the control arm and one of the combinations selected by a model-based design. Secondly, a flexible model is used to allow for toxicities at the MTC and the control arm to be modeled directly. We compare the performance of two-parameter and four-parameter logistic models with and without randomization to a current standard of such trials: a one-parameter model. It is found that at the cost of a small reduction in the proportion of correct selections in some scenarios, randomization provides a significant improvement in the ability to test for a difference in the toxicity risks. It also allows a better fitting of the combination-toxicity curve that leads to more reliable recommendations of the combination(s) to be studied in subsequent phases.
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Affiliation(s)
- Pavel Mozgunov
- a Department of Mathematics and Statistics , Bailrigg, Lancaster , Lancaster University , UK
| | - Thomas Jaki
- a Department of Mathematics and Statistics , Bailrigg, Lancaster , Lancaster University , UK
| | - Xavier Paoletti
- b Service de Biostatistique et d'Epidémiologie & CESP OncoStat, INSERM , Institut Gustave Roussy, Université Paris-11 , Villejuif , France
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32
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Mozgunov P, Jaki T, Paoletti X. A benchmark for dose finding studies with continuous outcomes. Biostatistics 2018; 21:189-201. [DOI: 10.1093/biostatistics/kxy045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 07/19/2018] [Accepted: 08/04/2018] [Indexed: 01/19/2023] Open
Affiliation(s)
- Pavel Mozgunov
- Department of Mathematics and Statistics, Lancaster University, Bailrigg, Lancaster LA1 4YF, UK
| | - Thomas Jaki
- Department of Mathematics and Statistics, Lancaster University, Bailrigg, Lancaster LA1 4YF, UK
| | - Xavier Paoletti
- Service de Biostatistique et d’Epidémiologie & CESP OncoStat, INSERM, Institut Gustave Roussy, Université Paris-11, 114, Rue Edouard Vaillant, Villejuif, France
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33
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Abbas R, Rossoni C, Jaki T, Paoletti X, Mozgunov P. A comparison of phase I dose-escalation designs in clinical trials with monotonicity assumption violation. Rev Epidemiol Sante Publique 2018. [DOI: 10.1016/j.respe.2018.03.336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Mozgunov P, Beccuti M, Horvath A, Jaki T, Sirovich R, Bibbona E. A review of the deterministic and diffusion approximations for stochastic chemical reaction networks. Reac Kinet Mech Cat 2018. [DOI: 10.1007/s11144-018-1351-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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