Related Experiment Video
Updated: Jun 14, 2026
04:53
A Clinical Trial Assessing the Safety, Efficacy, and Delivery of Olive-Oil-Based Three-Chamber Bags for Parenteral Nutrition
Published on: September 20, 2019
Regional differences in multinational clinical trials: anticipating chance variation
1Department of Statistics, Macquarie University, Sydney, Australia. ian.marschner@mq.edu.au
Clinical Trials (London, England)
|March 27, 2010
Summary
Multinational clinical trials can show wide regional variations in treatment effects due to chance. Assessing this expected variation during study design is crucial for accurate interpretation and managing expectations.
Area of Science:
- Clinical Trials
- Biostatistics
- Pharmacoeconomics
Background:
- Multinational clinical trials leverage diverse populations and pooled resources for robust treatment comparisons.
- However, significant regional variations in treatment effects can complicate interpretation, particularly when some regions favor the control arm.
Purpose of the Study:
- To quantify the expected chance variation in regional treatment effects within multinational studies.
- To advocate for the assessment of this variation during the study design phase to mitigate potential misinterpretations.
Main Methods:
- Utilized order statistics to measure inter-regional chance variation under the assumption of homogeneous treatment effects.
- Calculated the expected range of regional effects using extreme values and determined the probability of control-favoring regions.
Main Results:
- Chance variation results in a broad spectrum of expected regional effects; a five-region study (80% power) showed effects from no difference to double the true difference.
- With five regions, there's a ~50% chance of a region favoring the control; this exceeds 85% with ten regions.
- Increased study power offers minimal reduction in the wide range of regional treatment effect variations.
Conclusions:
- Anticipating substantial regional differences in multinational studies is essential.
- Evaluating the expected range of treatment effects during study design informs stakeholders and sets realistic expectations.
- This approach complements, but does not replace, end-of-study heterogeneity testing.
Related Concept Videos
01:16Clinical Trials
Clinical trials are prospective experimental studies conducted on humans to determine the safety and efficacy of treatments, drugs, diet methods, and medical devices. Using statistics in clinical trials enables researchers to derive reasonable and accurate conclusions from the collected data, allowing them to make wise decisions in uncertain situations. In medical research, statistical methods are crucial for preventing errors and bias.
There are four phases in a clinical trial. A phase one...
There are four phases in a clinical trial. A phase one...
01:11Clinical Trials: Overview
Clinical development focuses on how the drug will interact with the human body and encompasses four key phases of clinical trials, each serving a specific purpose in assessing the safety and effectiveness of new drugs. These phases overlap and build upon one another. Phase I involves a small group of healthy volunteers (typically 20-80 individuals) or, in cases where significant toxicity is expected, patients with the targeted disease, such as cancer or AIDS. The volunteers are tested for...
01:23Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches
Biopharmaceutical studies constitute a vital field aiming to enhance drug delivery methods and refine therapeutic approaches, drawing upon diverse interdisciplinary knowledge. In research methodologies, the choice between controlled and non-controlled studies significantly influences the study's reliability and accuracy.
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast, controlled...
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast, controlled...
01:27Principles of Pharmacogenetics: Types of Genetic Variants
The human genome is over 99.9% identical between individuals, yet genetic differences exist at millions of bases. The human genome contains approximately 3 million variant positions per individual, many of which are heterozygous, contributing to genetic diversity and individual traits. Genetic variations include single-nucleotide polymorphisms (SNPs), insertions, deletions, and copy number variations (CNVs).SNPs, the most common variation, involve single-base changes in DNA. These can be...
01:13Bioequivalence studies: Biowaivers
In certain scenarios, in vitro dissolution tests can replace in vivo bioequivalence studies. This is particularly true when a drug product, though available in varying strengths, maintains proportional similarity in its active and inactive ingredients. In such cases, the need for in vivo bioequivalence studies for lower strength variants may be waived, provided dissolution tests and in vivo studies on the highest strength yield satisfactory results.Bioequivalence can be indicated through...
01:20Bioequivalence Experimental Study Designs: Completely Randomized and Randomized Block Designs
Bioequivalence experimental study designs are crucial methodologies used in evaluating and comparing the bioavailability of different drug products. These designs are categorized into various types: completely randomized, randomized block, repeated measures, cross and carry-over, and Latin square designs.Completely randomized designs involve randomly allocating treatments to all subjects participating in the experiment. This allocation is achieved by assigning unique random numbers to subjects...