Explanatory Clinical Trial (ECT)
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An Explanatory Clinical Trial (ECT) is a Clinical Trial that is designed to test causal research hypotheses and determine the effects of an intervention under ideal circumstances.
- AKA: Explanatory Clinical Study, Efficacy Clinical Trial.
- Context:
- It can be designed to maximize the chance that some effect of a new treatment will be revealed by the study.
- It is focused on the clinical efficacy.
- It can be classified as a Phase II or Phase III Clinical Trial.
- Example(s):
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- Counter-Example(s):
- See: Decentralized Clinical Trial, Correlation, Therapy, Outcomes Research, Health System, Causality, Confounding, Drug Clinical Trial, Medical Device Clinical Trial, Clinical Procedure Trial, Observational Clinical Trial, Interventional Clinical Trial, Clinical Trial Management System, Clinical Trial Monitoring System, Clinical Trial Protocol, Clinical Trial Design System, Clinical Endpoint.
References
2021
- (Wikipedia, 2021) ⇒ https://en.wikipedia.org/wiki/Efficacy#Medicine Retrieved:2021-11-14.
- QUOTE: In medicine, efficacy is the capacity for beneficial change (or therapeutic effect) of a given intervention (for example a drug, medical device, surgical procedure, or a public health intervention). Establishment of the efficacy of an intervention is often done relative to other available interventions, with which it will be compared. Specifically, efficacy refers to "whether a drug demonstrates a health benefit over a placebo or other intervention when tested in an ideal situation, such as a tightly controlled clinical trial." These studies focus on a primary parameter to be shown statistically different between placebo and intervention groups. Comparisons of this type are called 'explanatory' randomized controlled trials, whereas 'pragmatic' trials are used to establish the effectiveness of an intervention regarding also non-specific parameters. Effectiveness refers to "how the drug works in a real-world situation", and is "often lower than efficacy because of interactions with other medications or health conditions of the patient, sufficient dose or duration of use not prescribed by the physician or followed by the patient, or use for an off-label condition that had not been tested."
2011
- (Patsopoulos, 2011) ⇒ Nikolaos A. Patsopoulos (2011). "A Pragmatic View on Pragmatic Trials". IN: Dialogues in Clinical Neuroscience, 13(2).
- QUOTE: The explanatory trial is the best design to explore if and how an intervention works, and the whole experiment is designed in order to control for all known biases and confounders, so that the intervention's effect is maximized. Usually the intervention under examination is compared with a placebo or with another active treatment. The pragmatic trial, on the other hand, is designed to test interventions in the full spectrum of everyday clinical settings in order to maximize applicability and generalizability. The research question under investigation is whether an intervention actually works in real life. The intervention is evaluated against other ones (established or not) of the same or different class, in routine practice settings. Pragmatic trials measure a wide spectrum of outcomes, mostly patient-centered, whereas explanatory trials focus on measurable symptoms or markers (clinical or biological). Figure 1 illustrates some main differences between pragmatic and explanatory trials.
Generally, the explanatory trials focus towards homogeneity, so that the errors and biases will influence the results as little as possible, whereas pragmatic trials are a race towards maximal heterogeneity in all aspects, eg, patients, treatments, clinical settings, etc. In order to overcome the inherited heterogeneity, which leads to dilution of the effect, pragmatic trials must be large enough (to increase power to detect small effects) and simple in their design. Simple trials are easier to plan, perform, and follow up.
- QUOTE: The explanatory trial is the best design to explore if and how an intervention works, and the whole experiment is designed in order to control for all known biases and confounders, so that the intervention's effect is maximized. Usually the intervention under examination is compared with a placebo or with another active treatment. The pragmatic trial, on the other hand, is designed to test interventions in the full spectrum of everyday clinical settings in order to maximize applicability and generalizability. The research question under investigation is whether an intervention actually works in real life. The intervention is evaluated against other ones (established or not) of the same or different class, in routine practice settings. Pragmatic trials measure a wide spectrum of outcomes, mostly patient-centered, whereas explanatory trials focus on measurable symptoms or markers (clinical or biological). Figure 1 illustrates some main differences between pragmatic and explanatory trials.
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2009
- (Thorpe et al., 2009) ⇒ Kevin E. Thorpe, Merrick Zwarenstein, Andrew D. Oxman, Shaun Treweek, Curt D. Furberg, Douglas G. Altman, Sean Tunis, Eduardo Bergel, Ian Harvey, David J. Magid, and Kalipso Chalkidou (2009). "A pragmatic–explanatory continuum indicator summary (PRECIS): a tool to help trial designers". In: Journal of clinical epidemiology, 62(5), 464-475.
- QUOTE: Randomized trials have traditionally been broadly categorized as either an effectiveness trial or an efficacy trial, although we prefer the terms “pragmatic” and “explanatory.” Schwartz and Lellouch described these 2 approaches toward clinical trials in 1967. These authors coined the term “pragmatic” to describe trials that help users choose between options for care, and “explanatory” to describe trials that test causal research hypotheses (i.e., that a given intervention causes a particular benefit).
We take the view that, in general, pragmatic trials are primarily designed to determine the effects of an intervention under the usual conditions in which it will be applied, whereas explanatory trials are primarily designed to determine the effects of an intervention under ideal circumstances.
- QUOTE: Randomized trials have traditionally been broadly categorized as either an effectiveness trial or an efficacy trial, although we prefer the terms “pragmatic” and “explanatory.” Schwartz and Lellouch described these 2 approaches toward clinical trials in 1967. These authors coined the term “pragmatic” to describe trials that help users choose between options for care, and “explanatory” to describe trials that test causal research hypotheses (i.e., that a given intervention causes a particular benefit).
2003
- (Tunis et al., 2003) ⇒ Sean R. Tunis, Daniel B. Stryer, and Carolyn M. Clancy (2003). "Practical Clinical Trials. Increasing the Value of Clinical Research for Decision Making in Clinical and Health Policy". In: JAMA. 2003;290(12):1624-1632.
- QUOTE: Clinical trials designed to assist health care decision-makers, referred to as pragmatic clinical trials or [[practical clinical trials (PCTs)]], are defined as trials for which the hypothesis and study design are formulated based on information needed to make a decision. They are distinguished from explanatory clinical trials, for which the goal is to better understand how and why an intervention works. Explanatory trials are designed to maximize the chance that some biological effect of a new treatment will be revealed by the study. The PCTs address practical questions about the risks, benefits, and costs of an intervention as they would occur in routine clinical practice. The most distinctive features of PCTs are that they select clinically relevant interventions to compare, include a diverse population of study participants, recruit participants from a variety of practice settings, and collect data on a broad range of health outcomes.
1967
- (Schwartz & Lellouch, 1967) ⇒ Daniel Schwartz, and Joseph Lellouch (1967). "Explanatory And Pragmatic Attitudes In Therapeutical Trials". In: Journal of chronic diseases, 20(8), 637-648.
- QUOTE: Suppose, for example, we require to compare two analgesics and assume first that the two are chemically very alike, differing only in a single radical. The biologist may then be interested to know whether the drugs differ in their effects when they are administered on an equimolecular basis. This is the explanatory approach.