clinical trial design

Question 1

uses of clinical study

Answer 1

to provide evidence
needed to test efficacy (strength/ability/how well something works)
needed to test safety (side effects etc)

Question 2

basic considerations involved in trial design

Answer 2

time scale
end points 
choice of control drug
choice of patients 
exclusion criteria
drug used

Question 3

choice of patients

Answer 3

age, race, compliance

Question 4

choice of control drug

Answer 4

• placebo- made to resemble drugs but do not contain an active drug
• actual drug

Question 5

end point

Answer 5

death, no. of hospital admissions, desired effect?

Question 6

exclusion from a clinical trial criteria

Answer 6

Pregnant women
Children
Elderly
Seriously ill patients

Question 7

Thalidomide

Answer 7

In the 1950s and the early 1960s, thalidomide was used to treat morning sickness during pregnancy.

It was found to cause severe birth defects. Now, thalidomide is being used to treat a skin condition and cancer.

Question 8

Drug used

Answer 8

Formulation (Capsule, tablet? etc)
dose
frequency

Question 9

Types of clinical trial

Answer 9

double blind
single blind
randomised 
placebo-controlled 
Parallel
Cross-over
Factorial
Cluster
retrospective

Question 10

double blind trial

Answer 10

Neither the doctor nor the patient knows which of the drugs they are getting (The study drug or the control drug)

Question 11

Single blind trial

Answer 11

The patient doesn’t know whether they are taking the study drug or control drug but the doctor does

Question 12

Randomised

Answer 12

Patients are assigned to a group at random to prevent bias

Question 13

Placebo controlled trial

Answer 13

in a group of 100 patients, 50 get placebo and the rest get the active drug and comparisons are made at the end

Question 14

Parallel design

Answer 14

two groups of treatments, A and B, are given so that one group receives only A while another group receives only
then evaluation of outcomes occurs

Question 15

Factorial design

Answer 15

test the effect of two or more treatments simultaneously using various combinations of the

• simplest factorial design is known as a 2x2 factorial design
  participants are randomly allocated to one of four combinations of two interventions (A and B, say).
  A alone
  B alone
  both A and B
  neither A nor B (control) treatments

this increases the portion getting active treatment

Question 16

crossover design

Answer 16

Randomisation
patient either gets A or B 
and the outcomes are evaluated 
then after the patients swap so the one on A tries B and vice versa
outcomes evaluated again

Question 17

Advantages of Cross-Over Designs

Answer 17

Address question of major interest
−Will this patient do better on drug A or drug B?
Removes “patient effect ie how that drug acts in that person”- thereby reducing variability and increasing precision of estimation
Opportunity to receive both treatments (or be assured of receiving active treatment at some point) is attractive to patients
Under assumption of no carryover effect, design provides more information than simple parallel design

Question 18

cluster

Answer 18

Groups or clusters randomly assigned, not individuals

− Examples: villages, classrooms, platoons

Question 19

Phases of clinical trials

Answer 19

Phase I, II, III and IV

Question 20

Phase I

Answer 20

Determine optimal or tolerable dose

Describe adverse event or PK profile (the drugs’ rates of absorption, distribution, metabolism and excretion)

Establish feasibility of treatment approach

Question 21

study hypothesis

Answer 21

study objective corresponds to the primary hypothesis of the study, e.g., the null hypothesis, H0

Question 22

what is a therapeutic trial designed to do?

Answer 22

show how large the drug’s therapeutic effect is

Question 23

What is a pilot study

Answer 23

a small scale preliminary study conducted in order to evaluate feasibility, time, cost, adverse events, and improve upon the study design before launching a full-scale research project

Question 24

prospective trial?

Answer 24

watches for outcomes, such as the development of a disease, during the study period
usually involves taking a cohort of subjects and watching them over a long period to see how things develop

Question 25

clinical significance is a subjective decision

Answer 25

The decision will depend on which disease process or condition is being studied, how many people are affected by the condition, etc

Question 26

statistical significance

Answer 26

the likelihood that a research result is true and not just mere chance
a bigger sample size can help this
if you have statistical significance this is not always an indicator of clinical significance