Lisa V. Hampson

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This paper considers the design and interpretation of clinical trials comparing treatments for conditions so rare that worldwide recruitment efforts are likely to yield total sample sizes of 50 or fewer, even when patients are recruited over several years. For such studies, the sample size needed to meet a conventional frequentist power requirement is(More)
Group sequential methods are used routinely to monitor clinical trials and to provide early stopping when there is evidence of a treatment effect, lack of an effect, or concerns about patient safety. In many studies, the response of clinical interest is measured some time after the start of treatment and there are subjects at each interim analysis who have(More)
BACKGROUND Many randomized controlled trials (RCTs) collect cost-effectiveness data. Without appropriate sample size calculations, patient recruitment may cease before the cost-effectiveness of the intervention can be established or continue after the cost-effectiveness of the intervention is established beyond doubt. PURPOSE We determined the frequency(More)
OBJECTIVES Definitive sample sizes for clinical trials in rare diseases are usually infeasible. Bayesian methodology can be used to maximise what is learnt from clinical trials in these circumstances. We elicited expert prior opinion for a future Bayesian randomised controlled trial for a rare inflammatory paediatric disease, polyarteritis nodosa (MYPAN,(More)
OBJECTIVES Chronic musculoskeletal pain and osteoarthritis can significantly limit the functional independence of individuals, and given that 25% of the population experience these problems, the socioeconomic impact is immense. Exercise and self-management have proven benefits for these conditions, but most trials tailor interventions for specific joints.(More)
Finding the right dose of a novel treatment is one of the most important tasks in early drug development. However , there is often uncertainty about the form of the relationship between dose and patient response at the time that the dose-finding trials are designed. In this presentation we develop Bayesian adaptive designs for Phase II cross-over trials(More)
Bayesian decision procedures have already been proposed for and implemented in Phase I dose-escalation studies in healthy volunteers. The procedures have been based on pharmacokinetic responses reflecting the concentration of the drug in blood plasma and are conducted to learn about the dose-response relationship while avoiding excessive concentrations.(More)
AIMS In the EU, development of new medicines for children should follow a prospectively agreed paediatric investigation plan (PIP). Finding the right dose for children is crucial but challenging due to the variability of pharmacokinetics across age groups and the limited sample sizes available. We examined strategies adopted in PIPs to support paediatric(More)
In randomised controlled trials, the effect of treatment on those who comply with allocation to active treatment can be estimated by comparing their outcome to those in the comparison group who would have complied with active treatment had they been allocated to it. We compare three estimators of the causal effect of treatment on compliers when this is a(More)
Multi-arm clinical trials that compare several active treatments to a common control have been proposed as an efficient means of making an informed decision about which of several treatments should be evaluated further in a confirmatory study. Additional efficiency is gained by incorporating interim analyses and, in particular, seamless Phase II/III designs(More)