1. Drug development

Question 1

name the different phases of drug development and their approximate time

Answer 1

1. discovery/research - 4yrs
2. phase 1 - 1yr
3. phase 2 - 2yrs
4. phase 3 - 4yrs
5. regulatory review - 1yr
6. phase 4

Question 2

describe the process of drug discover/research

Answer 2

i. Hits (potential drugs) identified and evaluated.
ii. Lead identification: correct physical properties? any ADME issues? can analogues be easily synthesised? can potency be improved with structure variation?

iii. Lead optimisation:
- increase potency (so can be taken in small tablet)
- optimise selectivity (prevent side effects)
- optimise physical properties and pharmacokinetics
- ensure efficacy in disease models

iv. Toxicology assessment, e.g. animal studies

Question 3

what is the aim of the different drug dev. stages

Answer 3

Phase I/IIa = can it work? Proof of Principle (PoP) studies - EARLY HUMAN SAFETY

Phase IIb/III = does it work? Proof of Concept (PoC) studies. And dose range finding. THERAPEUTIC EXPLORATORY

Phase III/IV = is it worth it? Pharmacoeconomics and post-marketing surveillance. THERAPEUTIC CONFIRMATORY

Question 4

describe phase 1

Answer 4

• 1yr
• small no. of HEALTHY volunteers
• investigates pharmacokinetics and evaluates safety
• requires MHRA approval

Question 5

describe phase 2

Answer 5

• 2 yrs
• 200-400 patients WITH DISEASE
• IIa = pilot study (dose finding)
• IIb = measures therapeutic action and determines dose for phase III

Question 6

describe phase 3

Answer 6

• 4 yrs
• 1000-3000 patients WITH DISEASE - large, multi-centre RCT
• determines efficacy against standard practice/placebo
• provides longer term safety data

Question 7

describe phase 4

Answer 7

• 10,000-50,000 patients
• drug can be prescribed
• pharmacovigilance for long-term safety
• seeking new indications for product or new formulations