What are clinical trials?
Clinical trials explore and test ways of diagnosing, treating, or preventing health conditions. The goal is to determine if the method is safe and effective.
A variety of things are evaluated through clinical trials, including:
Medications
New uses for existing medications
Medication combinations
Medical devices
What happens in phase 0?
Before a clinical trial start, investigators complete pre-clinical research using human cells or animal models. For example, they might test whether a new medication is toxic to a small sample of human cells in a laboratory or test the method on Animals.
What happens in phase one?
During phase I of a clinical trial, investigators look at the effects of the medication on small group of people that have no underlying health conditions.
This phase aims to figure out the highest dose humans can take without serious side effects. Investigators monitor participants very closely to see how their bodies react to the medication during this phase.
While pre-clinical research usually provides some general information about dosing, the effects of a medication on the human body can be unpredictable.
In addition to evaluating safety and ideal dosage, investigators also look at the best way to administer the drug, such as orally, intravenously, or topically.
What happens in phase two?
Phase II of a clinical trial involves a larger group of participants who are living with the condition that the new medication is meant to treat. They’re usually given the same dose that was found to be safe in the previous phase.
Investigators monitor participants for several months or years to see how effective the medication is and to gather more information about any side effects it might cause.
While phase II involves more participants than earlier phases, it’s still not large enough to demonstrate the overall safety of a medication. However, the data collected during this phase helps investigators come up with methods for conducting phase III.
What happens in phase three?
Phase III of a clinical trial usually involves up to 3,000 participants who have the condition that the new medication is meant to treat. Trials in this phase can last for several years.
The purpose of phase III is to evaluate how the new medication works in comparison to existing medications for the same condition. To move forward with the trial, investigators need to demonstrate that the medication is at least as safe and effective as existing treatment options.
To do this, investigators use a process called randomization. This involves randomly choosing some participants to receive the new medication and others to receive an existing medication.
Phase III trials are usually double-blind, which means that neither the participant nor the investigator knows which medication the participant is taking. This helps to eliminate bias when interpreting results.
The FDA, MHRA and EMA usually requires a phase III clinical trial before approving a new medication. Due to the larger number of participants and longer duration or phase III, rare and long-term side effects are more likely to show up during this phase.
If investigators demonstrate that the medication is at least as safe and effective as others already on the market, the FDA, MHRA and EMA will usually approve the medication.
What happens in phase four?
Phase IV clinical trials happen after the FDA, MHRA or EMA has approved medication. This phase involves thousands of participants and can last for many years.
Investigators use this phase to get more information about the medication’s long-term safety, effectiveness, and any other benefits.
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