Clinical Trials

Question 1

Allocation concealment

Answer 1

Means that the person randomising the patient does not know what the next treatment allocation will be.

Question 2

Why is Allocation concealment Key to the success of randomisation

Answer 2

– Protects random sequence– Prevents selection bias (also called allocation bias)

Question 3

Allocation concealment types

Answer 3

• Assignment by centralised 24 hour hotline (remote telephone )
• Pre-numbered or coded containers administered as per allocation
• Computer allocation • Sequentially numbered, sealed, opaque envelopes

Question 4

Blinding

Answer 4

Masks the assigned intervention during the whole trial•Why?–Reduces influence of subjectivity–Minimise observer bias

Question 5

Intention to treat

Answer 5

ALL participants analysed in the group assigned (irrespective of whether or not they completed, or received the treatment)
Why?•Preserves randomisation•Models real world

Question 6

Per protocol analysis

Answer 6

Only analyse participants who were compliant with thestudy protocol

Question 7

Complete case analysis

Answer 7

Only analyse participants with available outcome data.

Question 8

Differences only explained by …

Answer 8

1.Random error2.Treatment effect3.Systematic error

Question 9

Elements of a research question

Answer 9

PICOT:
Participants- Who
Intervention What
Comparison What
Outcomes What
Time when

Question 10

Types of trials

Answer 10

Parallel group trial
Factorial trial
Cross-over trial

Question 11

Trial phases

Phase 1•

Answer 11

First in humans: Evaluates safety, dose & PK/PD. Not randomised. In healthy volunteers or people with advanced disease (e.g. cancer). N=20-60. Extensive monitoring, clinic or hospital-based

Question 12

Trial phases

Phase 2a•

Answer 12

In target population: Small (<100 people), short-term studies of safety, dose ranging & “surrogate”efficacy, sometimes randomised.

Question 13

Trial phases

Phase 2b•

Answer 13

In target population: Larger (100s) short-term studies of surrogate & target outcome, Randomised.

Question 14

Trial phases

Phase 3•

Answer 14

In target population: Large (100-1000s), looks at long-term efficacy or effectiveness, and safety. Randomised. Looks at acceptability. Compares to usual care or as an adjunct.

Question 15

Trial phases

Phase 4•

Answer 15

In target population or general popn: Post-marketing surveillance, often pragmatic, and head-to-head comparison. Looks at acceptability, picks up rarer adverse events

Question 16

Good Design Elements:

Answer 16

® Randomisation
o Reduces confounding and produces equal groups
® Allocation Concealment
o Reduces selection bias
Blinding
o Reduces observer bias
® Complete Follow Up
o Reduces attrition bias
® Right Analysis
o Reduces Attrition bias