Stages I, II, III, and IV of clinical trials Flashcards
what does a clinical trial involve
- administration of new substances with therapeutic potential to people under controlled conditions for the purpose of determining
- efficacy
- bioavailability
- safety
- tolerability
- acceptability
what are the requirements of the medicines for human use regulations 2004
- good clinical practice
- good manufacturing practice
- regulatory inspection and enforcement
- protection of incapacitated adults
- protection of minors
- pharmacovigilance arrangements
what are the ICH guidelines for good clinical practice
- risks and potential benefits must be assessed before trials are started
- interests of individual study subject must take precedence over those of science or society
- all trial subjects must give consent
- trials must be scientifically sound
- trials must have a clear protocol
- trials must be approved by a properly constituted ethics committee
- only properly qualified staff may be involved
- should be adequate preclinical testing of product
- product should be of adequate quality
- trial subjects privacy and confidentiality must be assured
what are the 4 phases of clinical development
- phase 1- first administration and safety evaluation in man
- usually healthy volunteers - phase 2- early exploratory and dose finding studies in patients
- phase 3- large scale studies in patients
- phase 4- post marketing safety monitoring
what is the aim of phase 1 trials
- preliminary info in humans
- exploratory
- safety
- tolerability
- bioavailability
- pharmacokinetics
what is the design in phase I trials
- in healthy volunteers- defined in inclusion and exclusion criteria
- represent the variation of the population as a whole
- placebo controlled
- randomised
- double blind
describe the data collected in phase I trials
- adverse events
- pharmacokinetic parameters
- pharmacodynamics- preliminary evidence of efficacy
- proof of concept
what are some complications to consider in phase I trials
- most phase I volunteers are men
- women of reproductive age - genetic polymorphisms
- fast or slow metabolism
- accumulation of drug in slow metabolisers
- consider target population
- where is the drug to be marketed
describe phase Ia Single dose trials
- 4-8 cohorts of 6-8 participants
- escalating dose from one cohort to the next
- maximum tolerated dose determined
- before safety/tolerability issues arise
what do phase Ia single dose trials establish
- maximum tolerated dose
- pharmacokinetic parameters
- cmax, tmax, AUC, T1/2, Vd, Mean residence time
what is involved in phase Ib repeated dose trials
- similar participants to phase Ia
- escalating repeat dose
- establishes steady state dosing requirements
what are the aims of phase IIa trials
- exploratory
- preliminary safety and efficacy to support a go/no go decision
describe the design in phase IIa trials
- in patients
- dose and regimen based on phase I data
- placebo controlled
- randomised
- double blind
describe the data collected in phase IIa trials
- adverse events
- pharmacokinetic parameters
- pharmacodynamics- preliminary evidence of efficacy
- proof of concept
what are the aims in phase IIb trials
- confirmatory
- dose selection to support registration
describe the design in phase IIb trials
- patients in one or more indications
- selected dose levels
- placebo or standardised treatment
- randomised
- double blind
Describe the data collected in phase IIb trials
- adverse events
- pharmacokinetic parameters
- pharmacodynamics- preliminary evidence of efficacy
- proof of concept
what are the aims of phase III trials
- confirmatory
- provides efficacy and safety data to support registration
- may include pharmacoeconomics
describe the design in phase III trials
- patients in target indications
- including different groups - selected dose levels compared with placebo or standard treatments
- randomised
- double blind
describe the data collected in phase III trials
- statistically rigorous measurements demonstrating safety and efficacy
- in comparison with standard treatments
- may include pharmacoeconomics
give examples of reasons why a trial may fail
- insufficient biological activity
- unacceptable toxicity
- problems in design of trial
- measurement criteria
- patient selection
- sample size
- duration - problems in execution of trials
- randomisation of patients
- analysis of data
what are the aims in phase IV trials
- post marketing surviellence
- to reveal unexpected adverse effects/toxicity
describe the deign in phase iV trials
- treated patients
- cohort studies
describe the data collected in phase IV trials
adverse events
what is the yellow card scheme
- reports made by patients and healthcare professionals
- assessed at MHRA
- if a new side effect is identified, info about how the side effect profile compares with other medicines used to treat same condition is considered
- MHRA takes action to ensure that medicines are used in a way that minimises risk, while maximising patient benefit
where is the black triangle symbol indicated in
- BNF
- monthly index of medical specialties (MIMS)
- association of the British Pharmaceutical industry medicines compendium
- on advertising material
- in drug safety update
how are black triangle drugs and products monitored
- monitored for 2 years after marketing
- healthcare professionals are asked to report all suspected adverse drug reaction to these products through yellow card scheme
what are black triangle drugs
- where there is relatively limited info about safety of new drugs from clinical trials in UK
- trials generally involve only small umbers of eligible patients who take medicine for short period of time
- patients in clinical trials may not be fully representative of those who will use medicine when marketed
what are black triangle products
- contain new combination of active substances
- new route of administration or drug delivery system
- significant new indication which may alter the established risk/benefit profile of that drug
- established medicine which is to be used in a new patient population
how are problems with drugs revealed
- info supplied by manufacturers, including phase IV clinical trials
- side effects revealed through yellow card scheme
- alerts on newly marketed drugs through black triangle scheme
- quality checks on products carried out by MHRA inspectors
- tip offs about criminal activity, such as sale of counterfeit medicines
what is MHRAs defective medicines report centre
- issues alerts to healthcare professionals, hospitals, gp surgeries, wholesalers
- tells them when a medicine is being called or when there are concerns about the quality that will affect its safety and effectiveness
what are the classes of recall actions taken by regulators
- class 1- life threatening, immediate recall required
- class 2- harmful: recall required within 48 hours
- class 3- unlikely to harm patients, action required within 5 days
- class 4- no threat to patient safety, caution advised