Interventional Study Designs Flashcards
What is the key difference between interventional study designs and observational?
investigators select interventions and allocates study subjects to force intervention groups
Interventional study designs can demonstrate______
causation
What is the preclinical phase?
prior to human investigation
‘bench’ or animal research
What is Phase 0?
exploratory, investigational new drug
- assess drug taking actions and possibly pharmacokinetics in single or a few doses
- healthy volunteers
- very small N <20
- very short duration
What is Phase 1?
investigational new drug
- assess safety/tolerance and pharmacokinetics of one or more dosages
- healthy or disease volunteers
- small N (eg 20-80)
- short duration
What is phase 2?
- assess effectiveness
- diseased volunteers
- larger N (100-300)
- Short to medium duration
What is phase 3?
investigational new drug, indication/population
- assess effectiveness
- diseased volunteers
- larger N (500-3000)
- longer duration
What is phase 4?
post FDA approval
- assess long term safety, effectiveness, optimal use
- diseased volunteers
- population N (few hundred to few hundred thousand)
- wide range of durations
What are the advantages of interventional trials?
cause precedes effect (can demonstrate causation)
only designs used by FDA for approval process
What are disadvantages of interventional trials?
cost
complexity/time
ethical considerations
generalizability (external validity)
What is a exploratory study?
explores the ethics, causes, etc. of a drug in a non clinical setting. Such as if the drug is useful, or what dosage of the drug is needed
What is a pragmatic study?
Explains how we treat the diseases part of a clinical study, more flexible (can switch drug that subject is using if needed)
What are the two types of interventional study designs?
simple
factorial
What is a simple study design?
divides (randomizes) subjects exclusively into greater than or equal to two groups
tests a single hypothesis
What is a factorial study design?
Dives (randomizes) subjects into greater than or equal to two groups and then further sub divides (randomizes each of the groups into more sub groups
test multiple hypotheses
What are the benefits of a factorial study design?
improves efficiency for answering clinical questions increases study population sample size increase complexity increases risk of drop outs may restrict generalizability of results
In what ways can simple or factorial study designs be managed?
parallel
cross over
What is parallel study design?
groups simultaneously and exclusively managed
no switching of intervention groups after initial randomization
What is cross over design?
groups serve as their own control by crossing over from one intervention to another during the study
What is the wash out phase?
part of cross over design, when you wait until everything is cleared out of a patient before starting second group
What is the lead in phase?
all study subjects blindly given one or more placebos for initial therapy to ermine a new baseline of diseases
can wash out existing medication
can assess compliance of subjects
What are the disadvantages to cross over design?
only suitable for long term conditions which are not curable
duration of study for each subject is longer
carry over effects during cross over
treatment by period interaction
smaller N requirement only applicable if within subjects variation less than between subjects variation
complexity in data analysis
What are the outcomes/endpoints in interventional study design?
primary
secondary/tertiary/ etc.
composite
What is a primary outcome?
most important, key outcome
main research question used for developing study
