clinical trials

Question 1

Clinical trials are commonly classified into?

Answer 1

4 phases

Question 2

what is phase 1

Answer 2

Determines pharmacokinetics and pharmacodynamics and side-effect

Question 3

the audience for phase 1

Answer 3

smaller group - healthy volunteers

Question 4

what is phase 2A

Answer 4

small number of patients affected by particular disease - assesses optimal dosing

Question 5

what is phase 2b

Answer 5

small number of patients affected by particular disease -assesses efficacy

Question 6

what is phase 3

Answer 6

Assess effectiveness - involves 100-1000’s of people, often as part of a randomised controlled trial, comparing new treatment with established treatments

Question 7

what is phase 4

Answer 7

Postmarketing surveillance - Monitors for long-term effectiveness and side-effects

Question 8

A new drug is being trialled for its potential benefits with regards to 30-day survival following acute ischaemic stroke. In a study of 2000 patients with acute ischaemic stroke, 800 are given the new drug and 1200 are given a placebo.

Out of the group given the new drug, 40 patients die within 30 days. Out of the group given the placebo, 120 patients die within 30 days.

What is the number needed to treat?

Answer 8

NNT = 1 / Absolute Risk Reduction

The absolute risk reduction is the difference between the event rate in the treatment group and the event rate in the control group. Here, the experimental event rate (EER) is 40/800=0.05. The control event rate (CER) is 120/1200=0.1. The difference is the ARR, which is 0.05. The NNT is therefore 1/0.05=20