Drug development and clinical trials Flashcards
What is the difference between drug discovery and drug development?
Drug discovery is the identification of a new molecule whereas drug development is the processing and application of the new identified chemical into a usable form.
What is the approximate time and cost of developing a new drug?
Approx 9-10 years from discovery to market.
NZ 1 billion $ per drug
Note: 9 out of 10 drugs that are tested on humans do not make the market
What are the 5 main phases of drug development
Phase 0 = predictions for humans.
Testing of animals with similar enzymes such as rats to see likely effective conc, major route of elimination, mechanims of actions etc.
Phase 1 = Tolerability
First test of the new drug in humans. This is done at a VERY small conc and usually in young healthy individuals that do not have any health problems.
Phase 2 = Effectiveness
Testing the drugs in patients that actually have the targeted health problem. Usually they start off with a dose and if it shows sign of working then they continue to trial or if showing no effectiveness then the decision is made to abort.
Phase 3 = Safety
This is the biggest and most exspenive phase. The drug has proved to be effective and the ideal dose chosen so now it much be tested in a very large population. Any safety issues or adverse effects or interactions are identified.
Phase 4 = Post marketing
By this stage the drug has been approved and has reached the market. Often this is a nervous wait for drug developers as it could identify uncommon adverse effects that mean the drug is no longer reputable as safe. It is also a time to see if people follow the drug when prescribed it.
What are alternative medicines?
Medicines that are not known to be safe and effective.
What are the ABC’S of clinical trial design and what do they mean?
A = Assignment
What treatment are each of the subjects assigned to?
1. first come first served or
2. randomized
B = Blinding
Open (everyone knows), single blind (the patients dont know), double blind (the patients and doctors dont know).
C = Comparison
The good experiments will have control groups in order to account for factors that might influence the outcome that are not experimentally assigned.
Even better is to have a placebo.
S = Sequence
Is it a parallel design (different treatments are assigned to different groups) or a crossover design (test multiple things on the same group).
Clinical trials can be analysed in two main ways, what are these ways?
Intention to treat:
This analyses the study from the perspective that people would have taken what they were supposed to. This is always going to have bias.
As treated:
This analysis takes into account what people actually took and thus the underestimation bias that occur with the intention to treat model will be removed.
