drug development Flashcards
cost of developing medicines?
(3 marks)
- amount of money spent on preclinical / clinical study of drugs depends on drugs
- historically, more spent on clinical study after some drug development
- recently, more spent on preclinical studies
what does drug discovery include?
(7 marks)
- research into disease mechanisms, key molecules and processes involved
- this with reveal potential targets
- find potential agent that will act specifically on target
- this used to involve a search for natural components,
- but nowadays researchers tens to use cominatorial chemistry to loads of differernt compounds
- before screening them to see which bind to target
- if drug discovery goes well, result is = family of promising compounds
give 2 examples of chemicals found from plants?
(2 marks)
asprin + morphine
what happens at preclinical stage?
(5 marks)
- study lead compounds in more detail to find;
- how they are metabolised by body, where they go in body;
- how long they stay there and whether they are toxic
- also need to find out how compounds affect the target (e.g. partial / total inhibiton)
- refine compounds chemically to enhance good features + minimise bad (toxicity)
what are the 3 R’s that apply during preclinical stage?
(3 marks)
refinement, replacement, reduction
why may drug development stop?
(3 marks)
safety issues for patient, person handling drug / environment (side effects / adverse reactions)
carcinogenic effects = immediate termination
what happens at phase 1 (safety in target species)?
(6 marks)
- drug development narrow down to one compound with best combination of properties -
- action on its target, lack of toxicity, good access to where needed
- company apply for approval from medicines + healthcare regulatory authority (MHRA) to run phase 1 clinical trial
- involve small number healthy volunteers given small dose of drug + carefully monitored
- doses much smaller than those that have been safely used in animal testing
- test whether new drug is safe + reveal how drug is metabolised in living human
what happens at phase 2 (efficacy trials)?
(3 marks)
- first time patients involved
- small number volunteer patients take part + carefully monitored
- test whether new drug is safe to use in patients + whether appears to have positive effect on condition being treated
what happens at phase 3 (large clinical trial)?
(8 marks)
- involve many patients (100-1,000)
- usually randomised control trials - new drug compared with placebo / existing treatment
- trial is controlled =
- control group patients do not get new drug
- effects seen in treated group compared with control group
- trial randomised -
- patients assigned at random to either new drug / control group to avoid bias
- ideally, neither patient nor researcher should know what a patient has receieved (double-blind trial)
data collected in phase 3 trial must be submitted where?
(1 mark)
veterinary medicines directorate / EU equivalent
after submission to veterinary medicines directorate, what does the study receieve?
(1 mark)
animal test certificate
what happens at stage 4 studies?
(2 marks)
- companies choose to perform additional studies after submitting their dossier before medicine is authorised
- have commercial application - compare product to existing one
what happens during approval stage?
(6 marks)
- company can apply to MHRA for regulatory approval
- need to submit data from its earlier research + clinical trial to show new drug is safe + benefits patient
- each country has own regulatory system so company has to submit data to many authorities
- company submit drugs to scrutiny by national institute of health and clinical excellence (NICE)
- NICE assesses whether drug offers good value for money
- without NICE approval, healthcare providers will not usually make treatment available
how long does it usually take to get a product from submission to market?
(1 mark)
1 year
what happens during post-launch?
(4 marks)
- if drug gets approval from health authority, finally reaches market
- possible drug has rare side effects - so new drugs monitored after launch
- doctors recors ‘adverse events’ using ‘yellow card’ system, whcih is centrally monitored
- if drug causes issues, warning labels may be added to packaging, or withdrawn completely
