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8
Crossover Design
Randomization of order in which treatments are received
-AB or BA -Randomization promotes balance between treatment groups in
timing of exposure
Superiority
—Primary: mortality, exercise capacity —Secondary: quality of life, symptoms, lung function and mechanics, functional capacity Up to 7.5 years
-Often not controlled
Phase II:
-Usually 30-100 people -Preliminary information on efficacy, additional information on
safety and side effects
Phase III:
-Usually 100+ people -Assess efficacy and safety -Controlled, usually randomized
2
Lecture Outline
Discuss various trial design types
-Parallel -Crossover -Group allocation -Factorial -Large simple -Equivalency -Non-inferiority -Adaptive
People with severe emphysema
1,200
Randomized
—Lung volume reduction surgery plus medical therapy
—Medical therapy (standard therapy control)
Source: NETT Research Group (1999). Chest 1999; 116: 1750-61; NETT Research Group (1999). J Thorac Cardiovasc
Testing of both treatments in each patient
5
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Parallel Design Example: NETT
National Emphysema Treatment Trial (NETT)
- Phase III trial, unmasked
Population Sample size Allocation to treatment Treatments
Parallel Design
Simultaneous treatment and control groups Each person is randomly assigned to one treatment group Randomization removes treatment selection bias and promotes comparability of treatment groups Statistical comparisons made between treatment groups
Phase I:
-First stage in testing a new intervention in humans -Usually 10-30 people -Identify tolerable dose, provide information on drug metabolism,
excretion, and toxicity
Surg, 118: 518-528; Fishman, A., & Martinez, F., et al. (2003). N Engl J Med 348: 2059-73.
7
Parallel Design Example: NETT
Hypothesis testing Outcomes
Follow-up Number of recruiting centers
Types of Trial Design
Lea Drye, PhD Johns Hopkins University
Copyright © 2013 Johns Hopkins University and Lea Drye. All Rights Reserved.
Phases of trials
3
Section A
Comparison Structure: Parallel, Crossover, and Group Allocation Designs
The material in this video is subject to the copyright of the owners of the material and is being provided for educational purposes under rules of fair use for registered students in this course only. No additional copies of the copyrighted work may be made or
Multi-center (17)
Source: NETT Research Group (1999). Chest 1999; 116: 1750-61; NETT Research Group (1999). J Thorac Cardiovasc
Surg, 118: 518-528; Fishman, A., & Martinez, F., et al. (2003). N Engl J Med 348: 2059-73.
