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به نام ايزد يکتا. Clinical Trial Design. The common types Advantages and limitations Usual applications. Clinical Trial (on patients) vs. Field Trial (on healthy people) Community Trial (on communities). Before. After. Intervention. In phase II clinical trials OR
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به نام ايزد يکتا Clinical Trial Design • The common types • Advantages and limitations • Usual applications Dr. Khalili
Clinical Trial (on patients) • vs. • Field Trial (on healthy people) • Community Trial (on communities) Dr. Khalili
Before After Intervention In phase II clinical trials OR in serious diseases such as cancers Dr. Khalili
Notice: the standard methods for sample size calculation and data analysis considering subject as analysis unit are not appropriate here. Dr. Khalili
Be relax for few minutes Dr. Khalili
Advantages: • Allows within-patients comparisons of treatments • Removes interpatient variability • Provides the best unbiased estimates for the differences between treatments • Decreases number of patients needed Dr. Khalili
Limitations: • It is applicable where: • Objective measures for efficacy and safety are obtained • Chronic and relatively stable disease • Prophylactic drugs with relatively short half life • Relatively short treatment periods • Baseline and washout periods are feasible • It increases the duration of the study • Its analysis is not straightforward: • The paired design • The period and carry-over effects • The effect of loss to follow-up Dr. Khalili
Sequence (Period) Effect: The order in which the therapies are given may elicit psychological responses. Patients may react differently to the first therapy given in a study as a result of the enthusiasm may diminish over time. • Carryover Effect: If a subject is changed from therapy A to therapy B and observed under each therapy, the observations under therapy B will be valid only if there is no residual carryover from therapy A. There must be enough of a washout period to be sure none of therapy A or its effect remains. Dr. Khalili
To resolve the problom: Dr. Khalili
Two applications: • Quantifying the interaction between the two treatments • Opportunistic situations
A Full (a+1) * (b+1) Factorial Design for Combination Therapy of Two Components at a and b Dose Levels Dr. Khalili
Designs with ethical considerations • Adaptive Randomization • Zelen design • Variations of placebo-controlled trials: • Add-on design • Replacement design • Randomized Withdrawal design • Sequential analysis Dr. Khalili
And more complex DESIGNS … Dr. Khalili