Lecture 15-17 - Interventional Study Desings

Question 1

What main factors differentiate the different phases of interventional studies?

Answer 1

• purpose/focus
• population studied (healthy/diseased)
• sample size
• duration (can vary between diseases)

Question 2

What precedes most interventional studies?

Answer 2

-preclinical studies performed in a lab on tissue or animals

Question 3

What is characteristic of a phase 0 study?

Answer 3

-explanatory, new drug investigation

1. Assess drug-target actions and possibly pharmacokinetics in single or few doses
2. Healthy (possibly diseased) volunteers
3. Very small sample size
4. Very short duration

Question 4

What is characteristic of a Phase 1 study?

Answer 4

1. Assess safety/tolerance and pharmacokinetics of one or more doses
2. Healthy or diseased
3. Small sample size
4. Short duration

Question 5

What is characteristic of a phase 2 study?

Answer 5

1. Assess efficacy (continue to assess safety/tolerability)
2. Diseased volunteers
3. Larger sample size
4. Short-to-medium

Question 6

What is characteristic of a phase 3 study?

Answer 6

1. Assess efficacy (continue to assess safety/tolerability)
2. Disease volunteer
   - expansion of inclusion criteria and comparison groups
   - different statistical-perspectives can be taken
3. Larger sample size
4. Longer duration

Question 7

What is characteristic of a phase 4 study?

Answer 7

Post FDA-approval

1. Assess long term safety, effectiveness, and optimal use
2. Diseased volunteers
   - expand use criteria (comorbidities/multidrug)
3. Large populations
4. Wide range of duration (years to ongoing)

Question 8

What are the main advantages of interventional studies?

Answer 8

• they can demonstrate causation

- only process used for FDA approval

Question 9

What is a simple design of interventional studies?

Answer 9

• single randomized division process

- commonly only answers a single research question

Question 10

What is a factorial design for interventional studies?

Answer 10

• randomized division of subjects into groups followed by randomized subdivisions
• frequently used to answer more than one research question

Question 11

What is a parallel design of interventional studies?

Answer 11

• groups simultaneously and exclusively managed

- individuals do not switch between interventional groups

Question 12

What is a cross-over design of interventional studies?

Answer 12

• individuals switch between interventional groups

- each individual serves as their own control -> less people needed

Question 13

What is a wash-out phase?

Answer 13

• 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

Question 14

What is a lead-in phase?

Answer 14

• 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

Question 15

The word “randomize” indicates what type of study?

Answer 15

-interventional (phase 0-4) study

Question 16

What is the purpose of randomization?

Answer 16

• attempt to eliminate bias
• attempt to make groups as equal as possible
• can take into account confounders

Question 17

What differentiates random and non-random group allocation?

Answer 17

-subjects have an equal chance of being assigned to each group or they don’t

Question 18

What are the types of randomized allocation and what defines them?

Answer 18

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

Question 19

What are the types of masking used in interventional studies and what defines them?

Answer 19

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