+31 20 62 750 62

How clinical trials work

All medical innovations once started as possible solution from a skilled scientist. These ideas were then thoroughly tested throughout years to develop from basic research, through translational research, to clinical research. In the last stage, an innovation is tested for safety and efficacy in a limited number of patients, before it can finally be widely available on the market.

Scroll down if you want to know more about:

How clinical trials work
Clinical trial phases
Randomized, controlled trials & placebo
Blind & double-blind trials

About clinical trials

After a drug is investigated in a laboratory and it passes multiple safety tests, a clinical trial is needed to find out if the drug or treatment is safe, effective, has side effects, or is more effective than the current treatment. Clinical trials are used to look at risks and causes, new tests or scans or control symptoms or side effects of new drugs and complementary therapies.

In the case of Duchenne muscular dystrophy, most clinical trials aim to investigate new drugs or combinations of drugs, new ways of giving treatment and new types of treatment. Another type of trial is the observational trial, which is conducted to increase knowledge on, for example, disease progression or influence of care. This can be part of routine medical care.

Participating in a clinical trial is a voluntary choice. There are many factors that need to be considered before making a decision that is the best for you and your family. Things like time away from school and work, travel requirements to appointments, and the medical procedures required during the trial, need to be considered. In the end, it is a personal choice that you and your healthcare team have to make together. Deciding not to participate in a clinical trial will not affect the care you and your family will receive.

Considerations of joining a (clinical) trial

Thoroughly read the details of the study protocol
Discuss the trial and alternatives with your local doctor
Feel free to ask all the questions you may have to your doctor and/or the research team
A list of questions that are good to discuss can be found here

Clinical trial phases

Firstly, potential therapeutics are extensively tested pre-clinically in cells and animal models. Only the most effective drugs proceed into human studies.

Clinical drug development is conducted in different phases:

Phase 0 studies (sometimes called early Phase 1) are used to describe exploratory trials conducted before phase 1 trials start. This phase involves very limited human exposure to investigate how or whether a drug affects the body.
In Phase I studies, researchers will take tests to answer whether a drug is safe, and if or to which extend there are side effects. These small studies are usually conducted in healthy volunteers, unless this is not possible for the specific type of drug.
Phase II studies will focus on proof-of-principle, if the drug works like expected, and in finding the optimal doses. This is performed in patients with the specific disease. They are often performed in an open label setting (meaning that each patient and investigator knows whether it is receiving the therapy or not) and the intervention is compared to non-treated patients or patients receiving standard treatment.
Phase III is the pivotal phase. In this phase a large study is conducted to test whether the drug or treatment is better than existing ones. This is often done in a double-blind, placebo-controlled setting. This means that the active compound is compared to a placebo (non-effective) control and that both the patient and the researcher are unaware to which group the patient belongs. In this phase the effectiveness of the compound is studied in detail, to gather more information to apply for marketing approval.
Phase IV trials are done to gather more insight about long term risks, side effects and safety of the drug after it has been granted a license. Post-marketing studies describe additional information such as risks, benefits and optimal use from the treatment after it has been licensed for use and brought to market. This plays an important role in the part of pharmacovigilance, that monitors the effects of drugs after they have been licensed for use.

Not all clinical trials will pass all phases. Sometimes, researchers will find out in an early phase already the treatment is not working, or that side effects are worse than they thought. In these cases, the clinical trial will be stopped. Although the trial has ended, it still provides useful information that will advance research in Duchenne or Becker muscular dystrophy, ultimately benefiting the patient as well.

These phases are not applicable to observational studies.

How to choose a clinical trial

Check out an overview of all trials

Go to clinical trial overview

Randomised, controlled trials & placebo

In most cases, a clinical trial is randomized. This means patients are allocated to a specific group, usually automated, to make sure the different groups are as similar as possible. Each group than receives a different kind of treatment (active compound or placebo/standard treatment). This is called the control group. Researchers randomize trails to ensure they have no bias that could affect the results.

When a randomized trial has a control group, it is called a randomized controlled group. Some trials have more groups to test variations, for example in the height of the doses. When there is no standard treatment available for the control group to have, a placebo-group can be included: a medicine or procedure is given that has no therapeutic effect.

A placebo may only be used when no standard treatment is available. From an ethical perspective you cannot withdraw care according to the latest Standards of Care and it is unethical to give a placebo to a group of patients who are in need for treatment, so ethics committees will not grant permission to trials designed this way.

Blind & double-blind trials

In a blind trial, trial participants do not know which treatment they are receiving, meaning that they do not know in which group they are placed. They could either receive the tested drug, the standard treatment, or placebo. In a double-blind trial, both the doctor and the participant do not know whether which treatment the patient is getting.

Patients receive a number and treatment is labelled by a code, not specifying which treatment it holds. If an emergency occurs, the list of patients and code numbers can be made available, but usually participants and/or investigators do not known to which trail group the patient was allocated until the trial is finished.