Clinical Trials Flashcards
What are the different stages of the drug development process?
discovery research
preclinical trials
clinical trials - phase 1, 2 and 3
marketing authorisation and monitoring - phase 4
What is the difference between preclinical and clinical trials?
preclinical trials
- laboratory development and animal testing/toxicology
clinical trials
- testing volunteers and patients
What is a clinical trial?
any form of planned experiment involving volunteers/patients to identify the most appropriate treatment of future patients with a given medical condition
assess the benefit:risk ratio of new treatment against a control
looks at the pharmacokinetics, pharmacodynamics, adverse drug reactions, safety and efficacy exhibited by the investigated product
What is the purpose of clinical trials?
assesses the safety and efficacy of
- a new medication or device on a specific kind of patient
- a different dose of a medication that is commonly used
- an approved medication or device on a new kind of patient
assess whether the new medication or device is more effective for the patient’s condition than the the already used gold standard
What is phase 1 of clinical trials?
looks at the pharmacology and toxicology of the drug
- pharmacokinetics, pharmacodynamics, dosage, metabolism, safety and efficacy
starts the human volunteers at the lowest dose possible and is gradually escalated
- calculated from the animal studies
What is phase 2 of clinical trials?
therapeutic confirmation
- looks safety and efficacy
uses a large sample size to determine statistic validity
is randomised
uses a variety of designs
- concurrent control, comparison with baseline, crossover, blind/double blind
tests different doses to determine the therapeutic dose
- explores dose-response relationship
What is randomisation?
process of assigning clinical trial participants to treatment groups
- gives each participant a known chance of being assigned to each group
Why is randomisation needed?
explains the difference in outcomes between the treatment groups
- proves the intervention exhibits real effect and the difference is solely due to chance
What are the different methods of randomisation?
simple randomisation
permuted block randomisation
stratified allocation
minimisation method
What is simple randomisation?
assignment of subjects using a sequence of random numbers from a statistical textbook or computer generated sequence
What is permuted block randomisation?
blocks having equal numbers of As and Bs (A=intervention, B=control) are used with the order of treatments within the block being randomly permuted
- ABBA, AABB, etc
= a block of four has 6 different possible arrangements of 2 As and 2 Bs.
a random number digit assigns a block of treatment which sets the allocation order for the first four subjects and the process is repeated.
What is stratified allocation?
restricts chance imbalances by ensuring treatment groups are as alike as possible
ensures treatment balance on these known prognostic factors
What is the minimisation method?
used when you have very large number of data
use a new subject factor status
count the number of subjects with those factors on each treatment
- allocate to balance up scores (so give new patient the treatment which gives the smallest total sum)
- if sums for A and B are equal then one would use simple randomisation to assign the treatment.
What is concealment of the randomisation process?
those recruited people into the trial must be unaware of the group the participant will be assigned
What are the designs of clinical trials? What is the difference between them?
open trial - patient, doctor, pharmacy and sponsor know what is being used.
blind trial - patient does not know
double blind trial - patient, doctor and sponsor do not know
= minimises potential bias, ensure subjective assessments and decisions