Without clinical studies, there would not be enough relevant evidence to know whether a drug has the desired effect; for example, making people feel better, stopping the progression of the disease or even curing it. In addition, the safety of the drug and possible side effects are tested. New drugs are first tested in the laboratory, and those that show promise are then carefully tested on humans in clinical studies. The drugs that meet the strict requirements of the regulatory authorities are approved for the market. Often medicines fail.

The process of a drug development is a succession of clinical studies, structured in four phases. At first, few participants receive the investigated medicine. The number of people included in clinical studies grows along with the better understanding of the studied medicine.

In a phase I clinical study, first in humans, the participants (volunteers) help researchers to understand the safety of the investigational medicine. Depending on the studied drug/disease, the participants will be healthy or sick volunteers. Frequent clinical exams are taking place and also the participants are required to report any issues with the drugs immediately.

• 20 to 100 volunteers

• 1 week - several months

Volunteering in a phase II clinical study the participants support the researchers to determine effective dosages of the investigational medicine, as well as its side effects and risks. They suffer from the disease which the drug is tested for.

• Includes several hundreds volunteers

• Up to 2 years

During the phase III of a clinical study the main focus is on the side effects and its potential effectiveness of the investigational medicines. The volunteers are suffering from the disease and the clinical study is carried out globally.

• Several hundreds to thousands volunteers

• 1 to 4 years

If the investigational medicine brings the value, effectiveness and safety to the patients as hoped, then it will be approved by the Swissmedic (national authorisation). However, even after its approval it is crucial that the volunteers participate in long-term clinical studies, so called “open-label studies". These are designed to better understand the risks and potential benefits of the medicine over time.

• Several thousands of people

• More than a year

There are many reasons why people agree to take part in a clinical study.

• To help future patients - Many people agree to take part in a clinical study to help advance medical science. Clinical studies can greatly improve the lives of future patients. Some also feel the need to do something about their disease.

• Personal benefit - Many people also take part in a clinical study because they hope to gain some personal benefit. Some patients hope that the new drug can help them when all other options have been exhausted.

Whatever the reason for taking part in a clinical study, it is important to talk to your doctor or healthcare provider to discuss the possible risks and benefits.