What is a Clinical Trial? How Clinical Trials Work

Table of Contents

• Introduction
• What Is a Clinical Trial?
• Why Are Clinical Trials Important?
• What Are the Four Phases of Clinical Trials?
• Where do Clinical Trials Fit in the Journey
• What Participation in a Clinical Trial Looks Like
• Common Misunderstandings About Clinical Trials
• Are Clinical Trials Safe?
• Key takeaways
• Frequently Asked Questions

Introduction

You may have come across the term “clinical trial” while exploring treatment options for your condition. But what exactly are clinical trials, and are they something to think about? 

Clinical trials are a type of medical research that test investigational treatments, procedures, or ways of using existing medicines. The goal is to determine whether they are safe and whether they work for a particular condition.  

For some people, clinical trials may be an option to consider as part of their treatment journey. However, they are often not well understood. You may have questions about what clinical trials are, how they work, and what taking part might involve. 

Learning more about clinical trials can help you decide whether this could be relevant to your situation. This blog aims to provide clear, practical information to help you understand the topic and feel more confident if you choose to explore it further. 

What Is a Clinical Trial?

A clinical trial is a type of research in which investigational treatments – such as a drugs, devices, procedures or other interventions – are tested in people who voluntarily choose to take part. The aim is to understand whether they are safe and whether they work for a specific condition 

Taking part in a clinical trial may help some individuals, but it is important to know that it does not guarantee a cure or improvement. Some people may experience benefits, others may not, and side effects are also possible.  

Why Are Clinical Trials Important?

Clinical trials play a critical role in advancing medicine. Many medications, therapies, and medical procedures used today were studied in clinical trials. 

Through clinical trials, researchers can: 

• Evaluate whether treatments under development are safe and effective.
• Improve existing treatments and medical practices. 
• Better understand diseases and how they change over time. 

For people with a specific condition, some clinical trials may offer access to investigational therapies that are not yet widely available.  

Some people explore clinical trials when there are limited treatment options for their condition or when standard care is no longer working. Others may consider them earlier as part of conversations with their doctor about possible next steps.  

Whether a clinical trial may be a good option depends on each individual situation. That is why it is important to explore clinical trial options together with a doctor or healthcare team. 

What Are the Four Phases of Clinical Trials?

Clinical trials are typically carried out in several stages called phases. Each phase is designed to answer different research questions. 

The design of each phase may vary depending on the disease being studied, the existing standard treatment, and ethical considerations. However, the phases are generally defined as follows: 

Phase 1

Researchers study an investigational treatment in a small group of participants. The objective is to evaluate its safety, understand how the body responds to the treatment, determine an appropriate dose, and identify possible side effects. 

Phase 2

The treatment is tested in a group of people with the condition it is meant to help. Researchers look at whether it works, while continuing to monitor safety and side effects. In this phase, they also gather more information to help define the most appropriate dose. 

Phase 3

Phase 3 trials compare the investigational treatment to existing standard treatments or a placebo. A placebo looks like the treatment being tested but does not contain active medicine. These trials involve larger groups of people and help researchers confirm how well the treatment works. They also help better understand its risks before approval, as less common side effects can also be detected. 

Phase 4 (post-marketing clinical trials)

Phase 4 trials occur after a treatment has been approved for use. Researchers continue to collect information about long-term safety, as rarer side effects can be detected. Phase 4 clinical trials also allow to evaluate how well the treatment works in larger groups of people. 

Understanding these phases helps explain how treatments move from early research to routine medical care. For a more detailed explanation of each clinical trial phase, see the blog “Introducing clinical trials: phase 1–4 explained”  

Where do Clinical Trials Fit in the Journey

Clinical trials are sometimes described as a “last option,” but that is not always accurate. Trials can play different roles at different points in a person’s care journey. 

Some people begin exploring clinical trials when standard treatments are no longer effective or when few approved options exist for their condition. Others may consider a trial earlier, especially if: 

• They are newly diagnosed and a trial is studying first‑line treatment. 
• Their doctor suggests a clinical trial as an alternative or addition to standard care. 
• They want to contribute to research that may help others with the same condition. 

The role a clinical trial plays depends on factors such as the condition being studied, available treatments, prior therapies, and the purpose of the trial. A clinical trial is not a replacement for medical care, and it is important to discuss options with your healthcare provider when considering participation. 

Understanding where trials may fit can help set realistic expectations and guide conversations with your doctor about whether exploring clinical research makes sense for your situation. 

What Participation in a Clinical Trial Looks Like

Taking part in a clinical trial can look different from one trial to another. All clinical trials follow a detailed plan called a protocol. This plan sets out what researchers are studying, how the treatment is given, and what kinds of visits, tests, or assessments may be involved. Participants are also monitored throughout the trial to help protect their safety. 

Not everyone can join every clinical trial. Each trial has specific rules called eligibility criteria that help determine who the trial is meant for. Before anyone takes part, the clinical trial team explains the purpose of the trial, what participation may involve, and the possible risks and benefits through a process called informed consent. 

Some clinical trials assign people to different treatment groups by chance. This is called randomization. Depending on the clinical trial design, one group may receive the investigational treatment, while another may receive standard treatment or, in some cases, a placebo. These approaches may be used to help researchers compare results fairly. 

Common Misunderstandings About Clinical Trials

When people first hear about placebos and randomization, it can raise concerns or confusion. Below are some common misunderstandings, and what they usually mean in practice. 

“If there’s a placebo, I won’t receive any treatment.”
Not necessarily. In many clinical trials, participants continue to receive standard treatment, and the investigational treatment is added on top. A placebo may be used only when it is considered ethically appropriate and when no proven standard treatment exists for comparison. Some trial designs may also allow people in the placebo group to receive the investigational treatment at a later stage.  

“All clinical trials use placebos.”
This is a common misconception. Many trials compare a new treatment to the current standard of care rather than a placebo. Whether a placebo is used depends on the condition, available treatments, and ethical guidelines. 

“Randomization means doctors don’t consider what’s best for me”
Randomization is used to ensure that treatment groups are as similar as possible, which helps researchers understand whether differences in outcomes are due to the treatment itself. Even in randomized trials, participants are closely monitored, and safety remains a priority throughout the trial. 

Are Clinical Trials Safe?

Clinical trials are conducted under strict safety and ethical guidelines designed to protect participants. 

Before a clinical trial can begin, it must be reviewed and approved by ethics committees or institutional review boards (IRBs). These groups evaluate whether the trial is scientifically appropriate and whether participant safety is protected. Throughout the trial, researchers continue to monitor safety and report any potential concerns. 

However, clinical trials can still involve uncertainties and risks, such as: 

• Unknown or unexpected side effects. 
• Treatments that may not be effective. 
• Additional visits, testing, or travel requirements. 

If you would like to learn more about safety in clinical trials, you can read our dedicated blog, “Introducing Clinical Trials: Safety Information to Consider” 

If you decide you want to learn more about clinical trials, you may wish to speak with your doctor, consult trusted clinical trial registries, or explore additional support from services such as myTomorrows, which help patients understand clinical trial options and related information. 

Key takeaways

Clinical trials can feel complex at first, but understanding the basics can make it easier to decide whether they may be worth exploring as part of your treatment journey.  

Here are some of the main points to remember: 

• Clinical trials are a type of research that test investigational treatments, procedures, or new ways of using existing medicines for a specific condition. 
• They play an important role in advancing medicine. 
• They may offer some people access to investigational treatment options that are not yet widely available. 
• Whether a clinical trial may be relevant depends on each individual situation, so it is important to explore clinical trial options together with a doctor or healthcare team.
• Clinical trials take place in different phases, each designed to answer different questions about safety, dosing, how well a treatment works, and long-term use. 
• Not everyone will be eligible for every trial. Each of them is designed for a specific group of people based on factors such as the condition being studied, medical information, previous treatments, age, or overall health.  
• Participation looks different from trial to trial, but it often includes a defined treatment plan, scheduled visits, monitoring, and sometimes randomization to different treatment groups. 
• Taking part is voluntary, and while some people may benefit, clinical trials can also involve risks, uncertainties, and additional commitments. 

Frequently Asked Questions

At myTomorrows, we have a team of Patient Navigators, who are multilingual professionals with a medical background, and can support you with information  at the different stages of the clinical trial discovery and access process.