topic 6 pt 2: drug discovery & development

drug discovery: main approaches ; antibiotics

random screening for biological activity of large number of entities

drug discovery: main approaches ; aliskiren - renin inhibitor

identification of a new drug target

drug discovery: main approaches ; minoxidil

identification of new therapeutic use for a known drug

drug discovery: main approaches ; thiazide diuretics

chemical modifications of known molecule

drug discovery: main approaches ; cimetidine - H2 antagonist

rational drug design based on biological mechanism and chemical structure

drug discovery: main approaches ; recombinant DNA human insulin

biotechnology and cloning which uses genes to produce larger proteins

drug discovery: main approaches ; paracetamol and codeine

combination of drugs to obtain a synergistic effect

drug development (5 steps)

1. discovery of drug

2. perform studies to define PD profile

3. modify drug to improve PD and PK profile

4. identify lead compound

5. conduct clinical trials

PHASE I STUDY: objective

to ascertain the effects of the new drug in the human body

PHASE I STUDY: type of subjects

1. healthy volunteers

2. patients

PHASE I STUDY: sample size

10 - 100

PHASE I STUDY: duration

several months to a year

PHASE II STUDY: objective

1. to explore the therapeutic efficacy of the test drug in patients and its safety

2. to determine the doses and regimen for phase III trials

PHASE II STUDY: type of subjects

patients having the medical condition that the drug is designed to treat

PHASE II STUDY: sample size

50 - 200

PHASE II STUDY: duration

1 - 2 years

PHASE III STUDY: objective

1. to obtain safety and efficacy data in order to satisfy the product licensing authorities requirements

2. to establish the long-term effectiveness of the drug in a larger population

PHASE III STUDY: type of subjects

patients having the medical condition similar to the ultimate use of drug

PHASE III STUDY: sample size

several hundreds to thousands

PHASE III STUDY: duration

3-5 years

PHASE IV STUDY: what is it

1. post-marketing surveillance study

2. post-licensing studies in target population with board entry criteria

PHASE IV STUDY: objectives

1. to broaden experience in clinical practice and demonstrate the drug’s safety and efficacy in a real-life situation

2. to optimize drug use after approval