Clinical trials
Definitions & Key takeaways
Clinical trials are research studies that test how well new medical treatments work in people, and they are used to determine whether a new treatment is safe and effective. In most cases, people participating in clinical trials do not receive any direct benefit from it.
Clinical trials usually involve two types of participants: the experimental group, the control group, and the placebo group. The experimental group receives the new treatment; the control group receives a standard treatment or placebo (a medicine or other preparation with no therapeutic effect).
Clinical trials are scientific research studies that help determine the safety and effectiveness of an intervention. This could be a new medication vaccine device procedure or anything with therapeutic purposes.
Clinical trials are done on humans and are often the last step before an intervention is approved for use by the general public.
Now, the main goal of a clinical trial is to find out if the intervention actually works. And for that, there needs to be an experimental group that gets the new intervention and a control group that doesn't.
In addition, researchers should eliminate as many external factors as possible as they could affect the results. Now, there are multiple ways to design a clinical trial.
So let's go over a couple of them. The gold standard is the randomized controlled clinical trial.
So as an example, let's say there's a new vaccine that's being developed for a viral epidemic. As the participants, we'll need a group of people who tested positive for the infection.
Each person will be randomly assigned to either the experimental group who will receive the vaccine or the control group who will usually receive a placebo.
Now, if there's already an effective treatment available for a disease. It would be unethical to give a placebo.
So the control group will receive the available treatment instead. Now to limit bias, both the people administering the intervention and the people receiving it won't know who's in the control group and who's in the experimental group.
And this is called double blind. When the people assessing the data also don't know who's in what group.
It's a triple blind having placebos and blinded studies will help ensure that any difference between the results of both groups is most likely due to the intervention that's being tested and not external factors.
Another type of design is the pre post study where an individual will be their own control. So for example, to test a medication for rheumatoid arthritis, we could measure the pain and joint mobility of the test subject before giving the medication.
And then again, after they've been treated for a specific amount of time to see if there's any improvement. A third type of design is a factorial design which allows for the study of multiple interventions and their combinations.
So for a new antidepressant medication, you can compare the effect of the medication combined with psychotherapy, the effect of a placebo medication with psychotherapy, antidepressant medication and placebo psychotherapy and the effect of a placebo medication combined with placebo psychotherapy.
Phase one is focused on assessing the safety of the new medication in humans. So let's say a group of researchers are developing a new anti viral medication for a new pandemic.
For phase one, the research team will need to find a small group of test subjects which is often made up of healthy volunteers or patients with the disease of being treated by the medication.
This is because people with other illnesses like gastrointestinal liver or kidney problems might absorb metabolize and eliminate the medication abnormally and give incorrect data.
Next. The research subjects will be given the medication and then be closely monitored in a hospital setting.
In general, an initial dose based on animal studies will be administered and the dose will be gradually increased until a safe but potentially therapeutic level is found for use in phase two.
Phase two is done in a clinical setting with medical supervision for safety. During this process.
The pharmacokinetics and the pharmacodynamics of the medication are also studied and information like time to maximal plasma concentration, elimination, halflife and bioavailability are collected.
Potential side effects are also identified and studied intensively for some medications with severe side effects like chemotherapy agents.
It's unethical to test them on healthy subjects. In these cases, people with the disease that exhausted all of their options can volunteer to participate in phase two.
The focus is to find initial evidence of efficacy. Efficacy means the capacity of the medication to bring about the desired response.
So, in our anti viral medication example, the researchers are trying to find evidence that the medication can treat the viral infection in humans.
For this phase. The subjects need to have the disease that the medication is supposed to treat and the sample size is bigger than phase one.
So our researchers will need to find a group of volunteers who have the viral infection and then conduct small randomized controlled trials.
They can start with the dosage found in phase one and try to find the therapeutic dosage which is the quantity of medication that will achieve a therapeutic effect in the average person.
Next, they will look at efficacy and just how effective the medication is in treating the viral infection. In addition, further data in the medication safety and side effects can be gathered.
Now, if the results look promising, the trial goes into phase three. Phase three focuses on providing concrete evidence that proves the medication has therapeutic benefits to do this.
A large sample size is needed consisting of 100s to thousands of people that have the disease. This phase is also where the medication is compared to other commonly used treatments to see if it's just as effective or better.
So going back to our example, the researchers will conduct large scale randomized controlled trials at multiple clinics across the country.
If the data shows that the antiviral is effective in multiple large samples, they can now apply with regulatory agencies for approval of the medication in the United States success in phase three is the basis for approval by the Food and Drug Administration or FDA for short.
Once approved, the medication can go on the market. The entire process from starting development to reaching the market usually takes around 15 years in the US.
With phase three being the longest. Finally, after the medication is on the market, we have phase four which gathers data based on observation and statistics from the general public using the medication.
The population in phase four can be huge and very diverse. And the goal is to identify any rare or long term side effects of the medication and side effects in populations that were not well studied in the previous phases.
Phase four can also provide additional information on how to use the medication optimally such as lower and higher doses than those used in the previous phases.
Ultimately, if a serious safety concern is found, the medication can be recalled from the market and banned. All right.
As a quick recap, clinical trials are scientific research studies done on humans to analyze an interventions effectiveness and safety.
The gold standard of a clinical trial is the randomized controlled clinical trial. But variations like pre post design and factorial design are also used for a new medication.
A clinical trial is done in four phases which can be remembered with the mnemonic. All medications need the seal of approval, which stands for safety efficacy approval and long term phase one tests the medication in a small group of closely monitored subjects to see if it's safe for humans.
Phase two tries to establish initial evidence of efficacy by testing it on a moderate size group of people affected by the condition.
In question. Phase three looks at a large population with the condition to provide proof that the medication is effective, which will then be used as the basis for approval by regulatory organizations for the market.
Phase four is done after the medication has been on the market and looks for long term or rare side effects that might have been missed if it's found to be unsafe.
A recall and a ban might be needed.
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