Lecture 15-17 - Interventional Study Desings Flashcards
What main factors differentiate the different phases of interventional studies?
- purpose/focus
- population studied (healthy/diseased)
- sample size
- duration (can vary between diseases)
What precedes most interventional studies?
-preclinical studies performed in a lab on tissue or animals
What is characteristic of a phase 0 study?
-explanatory, new drug investigation
- Assess drug-target actions and possibly pharmacokinetics in single or few doses
- Healthy (possibly diseased) volunteers
- Very small sample size
- Very short duration
What is characteristic of a Phase 1 study?
- Assess safety/tolerance and pharmacokinetics of one or more doses
- Healthy or diseased
- Small sample size
- Short duration
What is characteristic of a phase 2 study?
- Assess efficacy (continue to assess safety/tolerability)
- Diseased volunteers
- Larger sample size
- Short-to-medium
What is characteristic of a phase 3 study?
- Assess efficacy (continue to assess safety/tolerability)
- Disease volunteer
- expansion of inclusion criteria and comparison groups
- different statistical-perspectives can be taken - Larger sample size
- Longer duration
What is characteristic of a phase 4 study?
Post FDA-approval
- Assess long term safety, effectiveness, and optimal use
- Diseased volunteers
- expand use criteria (comorbidities/multidrug) - Large populations
- Wide range of duration (years to ongoing)
What are the main advantages of interventional studies?
- they can demonstrate causation
- only process used for FDA approval
What is a simple design of interventional studies?
- single randomized division process
- commonly only answers a single research question
What is a factorial design for interventional studies?
- randomized division of subjects into groups followed by randomized subdivisions
- frequently used to answer more than one research question
What is a parallel design of interventional studies?
- groups simultaneously and exclusively managed
- individuals do not switch between interventional groups
What is a cross-over design of interventional studies?
- individuals switch between interventional groups
- each individual serves as their own control -> less people needed
What is a wash-out phase?
- a period where the individual is receiving no treatment before they are switched between interventional groups
- ensures that previous treatment has worn off before starting new treatment
What is a lead-in phase?
- occurs before intervention is began
- “practice” used to ensure that individuals can comply with study protocol
- can act as a wash-out for patients normal medications
The word “randomize” indicates what type of study?
-interventional (phase 0-4) study
What is the purpose of randomization?
- attempt to eliminate bias
- attempt to make groups as equal as possible
- can take into account confounders
What differentiates random and non-random group allocation?
-subjects have an equal chance of being assigned to each group or they don’t
What are the types of randomized allocation and what defines them?
Simple:
-equal probability of getting into each group
Blocked:
-randomized allocation but ensures equal group sizes (at the end of a block of distribution you look at how many are in each group and possibly force allocate to underpopulated group)
Stratified:
-randomized allocation within strata of known confounders
What are the types of masking used in interventional studies and what defines them?
Single-blind:
-study subjects do not know what interventional group they are in
Double-blind:
-both investigators and study subjects don’t know what interventional group the subject is in
Open-label:
-both investigator and study subject know which interventional group the study subject is in
