RAT: Phase 3 Clinical Trials Flashcards
What are phase 3 clinical trials?
Phase 3 clinical trials are often called randomized controlled trials (RCT). They are the main studies used for the licensing and marketing of a drug.
How many participants are involved in a phase 3 clinical trial?
Phase 3 trials are done on thousands of people who have the targeted disease to get information about the drug in a diverse population.
What is the goal of phase 3 clinical trials?
To determine how safe and effective the drug is compared to no treatment or the current recommended therapy.
What is the duration and cost of phase 3 clinical trials?
Phase 3 clinical trials are usually longer than phase 2 studies. That can be months to years. They’re also the most expensive part of drug development, as they may cost $1 million to upwards of $50 million.
Where are phase 3 clinical trials done?
Phase 3 trials are conducted at centres in many cities in order to get the required number or a diversity of patients.
What are the three stages of phase 3 clinical trials?
1) determining enrolment prior to study
2) allocating participants to treatment groups and conducting the trial
3) monitoring and analyzing the results
Explain the enrolment process in phase 3 clinical trials.
The people a new drug is tested on have to be carefully defined. These people can be part of the target population and the study population.
Target Population: the group of patients for whom the drug is intended.
Study Population: a subset of the target population that meets all required criteria.
The factors that influence who can be included in the study population art inclusion/exclusion and consent.
Inclusion/Exclusion: define characteristics of the patients to be included in the study in order to determine who is eligible to be in the trial. The study population must be defined to eliminate variables other than the drug under study that may influence their results, while also representing the target population. For example the severity of a disease should be defined. Patience with diseases that can influence the results are typically excluded, but comorbidities are often included to be representative of the target population.
Consent: informed consent must be obtained. This consists of a document written in non-scientific language that outlines the purpose of the study, the procedures, and all potential risks and benefits. The investigators must ensure that the participant fully understands the consent form before it is signed. These documents are reviewed by an independent institutional ethics review board to protect the rights of participants. At any time during the study, a participant can revoke their consent and withdraw from the study without penalty.
Explain the treatment allocation process in phase 3 clinical trials.
Double Blind Design: phase 3 studies are conducted in a double blind manner, where neither the investigator nor the study subject is aware of the treatment the study subject is assigned to. This prevents bias that can occur if a subject believes a drug will work or if the investigator may be expecting positive results.
Randomization: patients are assigned to the experimental treatment group or a control group through randomization that is done by a computer generated system. This ensures that confounding variables are distributed equally between experimental and control groups and removes potential bias in assigning patients.
Control: the efficacy and safety of the experiment drug has to be compared to a control drug which is either a placebo or gold standard drug.
- Placebo: does not contain any active drug, but is identical in appearance, color, taste, and administration methods. Almost everyone responds to the act of taking a drug simply because they believe it would work. This is in specifically in sick, anxious patients.
- Gold Standard: drug that is excepted by the medical community as the best available treatment for the specific disease at that time. If a gold standard drug is available, that is what the control group receives as it is unethical to withhold treatment if one exists.
Explain the results process in phase 3 clinical trials.
To determine if the treatment was more or less effective than the control, an outcome that measures how much the drug worked is measured and compared for each patient. This should be done in an objective and reliable manner.
There are three factors that greatly influence the interpretation of a trial and must be considered when analyzing results. These are:
Compliance: for the results of a trial to be valid, patient compliance must be determined. Patient compliance can be as low as 50% to 60%. For orally administered drugs, participants are asked to return their unused drugs at each clinic visit to receive a new batch of the appropriate drug. Then, a count of the remaining tablets indicates compliance. For drugs given intravenously, compliance is measured by checking that the nurse signed off on administering the drug.
Quality of Life: not all drugs will improve the quality of life and patients. Some drugs can be effective in treating the disease, but may have adverse effects or be so cumbersome to take that it may not improve overall life quality. This must be considered when determining the usefulness of a drug.
Statistics: the measured outcome of the experimental drug must be compared to the measured outcome of the control drag with statistics. Only proper use of statistics can determine whether there is a difference that is real, or a difference that happened by chance.
