Getting started

What is drug or vaccine development?

Drug or vaccine development is the journey from an idea for a potential medicine or vaccine all the way through to bringing that new medicine or vaccine to patients who need it. The development lifecycle includes laboratory research and a series of clinical trials in people. Along the way, important information is collected about the potential medicine or vaccine and how it affects clinical trial participants. If that information shows the potential medicine or vaccine is safe and effective, clinical trial sponsors provide the information to regulatory authorities, such as the European Medicines Agency (EMA), which decide whether to approve the medicine’s or vaccine’s use by patients.


Most clinical trials conducted by the Pfizer Clinical Research Unit (PCRU) are phase 1 studies involving healthy participants, who do not have the disease or condition that will later be studied. Phase 1 studies provide important information about the amount of the study medicine to be given and how often it should be given, as well as about the safety of the study medicine.


To watch a video about phase 1 of drug development, click Learn More.

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What are clinical trials?

Clinical trials (or research studies) are a type of medical research in which people volunteer to take part. Clinical trials commonly study how potential medicines and other medical treatments affect the participants.


All medicines and vaccines that become available today for use in patients are first tested in clinical trials involving hundreds to thousands of people.

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What happens in a clinical trial?

What happens in a clinical trial depends on the ‘protocol.’ A protocol is a detailed document that explains the purpose of the clinical trial and how it will be run. If you consider joining a clinical trial, these details will be explained to you as part of the informed consent process. They include:


  • the length of the clinical trial
  • the study medicines, procedures, and tests in the clinical trial
  • the schedule of study activities
  • information about who can participate
  • how side effects will be tracked, managed, and reported
  • the rules that must be followed


To watch a video about what typically happens in a phase 1 clinical trial, click Learn More.

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Who will oversee my care in a clinical trial? Can I continue to see my regular medical doctor?

As part of a clinical trial, your study-related medical care is provided by the study team at the location where you’re participating. This includes the principal investigator (or study doctor) — the healthcare professional who conducts and takes responsibility for the trial at that location — as well as other clinical study team members.


During your clinical trial, you may also continue to see your regular medical doctors for any care that is not related to the study. It is important for you to tell your study team about other conditions you might have, and to let them know which other doctors are caring for you. This helps the study team coordinate your overall care.


If you participate, the clinical trial will provide study-related medical care, and your regular doctors will address the other aspects of your health. Your regular medical doctors can also work with the study team to understand the details of the study and make sure it does not conflict with any medicines or treatments you are receiving outside of the study.

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Are clinical trials safe?

All clinical trials have possible risks. The known and unknown risks of participating in a specific study will be explained to you during the informed consent process that happens before you decide whether to participate.


Clinical researchers must follow guidelines and regulatory requirements to help protect the rights, safety, and well-being of clinical trial participants. These include Good Clinical Practice (GCP). GCP is an international ethical and scientific quality standard for designing and conducting clinical trials.


There are also many entities that provide oversight of clinical trials. These include the European Medicines Agency (EMA), ethics committees, and data safety and monitoring boards.

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Who can join a clinical trial?

We encourage everybody to consider joining clinical trials. There are many types of clinical trials that study different aspects of health in people with a variety of backgrounds and conditions. Each clinical trial has its own criteria for who may participate. These are called eligibility criteria.


Eligibility criteria include things like your age, sex, overall health, type of condition, and your medical treatment history. As part of the steps to join a clinical trial, the study doctor will confirm whether you meet all eligibility criteria and are able to participate.


To watch a video about the process of joining a clinical trial at the Pfizer Clinical Research Unit, click Learn More.

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Is there any cost to participate in a clinical trial?

Pfizer generally covers the cost of the study medicines and procedures that are part of its clinical trials.


Pfizer is also committed to reimbursing participants for reasonable clinical trial-related expenses such as transportation, parking, and meals.


Because each study is different, we encourage you to ask the study team any questions you have. You can also refer to the informed consent document for the details about any costs for study participants and study-related reimbursement.

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For current clinical trial participants

Who should I call if I have a question about my clinical trial?

A member of the study team at the location where you’re participating is typically your main point of contact throughout the clinical trial. This member of the study team can answer many questions about the day-to-day details of the study. Depending on your question, he or she may refer you to other members of the study team, such as the principal investigator.

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What should I do if I experience a side effect?

You should contact the study doctor as soon as the side effect happens, and follow any instructions that he or she provides. The study doctor may determine that you need additional procedures or medicines to help manage the side effects. Additional details of what you should do if you experience a side effect may be explained in the informed consent document for your study.


All side effects should be reported to the study doctor, even if you believe the side effect is mild or that it wasn’t caused by the study medicine. Contact information for the study doctor, including a 24-hour emergency contact number, can be found on study materials you received. These materials include the informed consent document and a medical emergency contact card.

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What should I do in the case of a medical emergency?

Seek medical assistance immediately. All participants in Pfizer clinical trials are provided with a medical emergency contact card. You should provide this card to the healthcare professionals caring for you in the emergency. The healthcare professionals can call the phone number on the card to learn about the clinical trial and the study medicine that you are receiving. Additional details of what you should do in case of an emergency may be explained in the informed consent document of your study.

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What happens if I decide I don’t want to continue in the clinical trial?

You are always free to leave a clinical trial at any time and for any reason. If you decide to leave the study, please tell the study doctor so that you can end your participation in the safest way. The study doctor will explain how to return the study medicine and what other steps may occur.


Your decision to stop participating in the study will not affect your regular medical care or any benefits to which you are entitled. The informed consent document of your study may provide more details on what happens if your participation in the study ends.

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For past clinical trial participants

How do I find out if the study medicine is now available to patients?

If health authorities such as the European Medicines Agency (EMA) approve the study medicine for use by patients with a specific condition, doctors and pharmacists will become aware that it can be prescribed. Pfizer typically releases public statements when its new medicines are approved, and we list our approved medicines on We also commonly create websites and other materials to inform doctors about our medicines.


Keep in mind that study medicines typically go through a series of clinical trials before they are submitted to health authorities for approval. For a study medicine to be considered for approval, those clinical trials must collectively show that the study medicine is safe and effective. Since clinical trials at the PCRU in Brussels are typically phase 1 trials, approval may be years away or may never come.

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Our clinical research unit (PCRU)

What is the Pfizer Clinical Research Unit (PCRU)?

Pfizer’s clinical research unit in Brussels is a leading research facility that conducts mostly phase 1 clinical trials. Pfizer has two clinical research units: one in New Haven (Connecticut, USA) and the other in Brussels, located on the university campus of Erasmus Hospital. The Brussels PCRU is a modern facility occupying the top two floors of the day hospital of Erasmus Hospital. It has a capacity of 72 beds and includes examination rooms, a laboratory, and a pharmacy.

Since it opened in 1992, the Brussels PCRU has enabled the development of many medicines, running more than 500 phase 1 clinical studies with the help of several thousand participants. The PCRU’s qualified staff of doctors, nurses, pharmacists, laboratory technicians, and administrative employees work together to run these clinical studies and, in so doing, ultimately help patients around the world.

The Brussels PCRU has also extended its activities to the nearby Centre Administratif Hospitalier (CAH) building, where the PCRU conducts clinical research screening and other outpatient study activities. Pfizer also operates a satellite site in Hasselt, on the Salvator campus of Jessa Hospital. This site provides participants with the option to attend outpatient visits in Hasselt rather than in Brussels.

The majority of clinical studies at the Brussels PCRU are conducted on behalf of study teams located in the United States: Groton (Connecticut), New York (New York), La Jolla (California), Cambridge (Massachusetts), Collegeville (Pennsylvania) and Boulder (Colorado), as well as in China and Japan.

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Why are healthy participants needed for many of the clinical trials that take place at the PCRU?

Healthy participants in these clinical trials help us understand how a study drug affects the body before patients with the condition are included. This is one way to assess a study drug’s safety before giving it to those who have a medical condition.

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What is the screening visit?

The screening visit is a key step to joining a clinical trial. At this visit, you will review the informed consent document with members of the study team at the PCRU. The informed consent document describes the details of the clinical trial, including what your rights and responsibilities would be as a participant, and any potential risks, so that you can decide whether you’d like to participate. The study team will answer any questions you may have.

If you decide to participate, you will sign the informed consent document and then undergo study-required tests, procedures, or assessments to confirm whether you meet the eligibility criteria for the study. These may include blood tests, an electrocardiogram (a test that uses sensors attached to the skin to check your heart’s rhythm and electrical activity), and vital signs.

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Can you describe a typical day for a clinical trial participant at the PCRU facility in Brussels?

A typical clinical trial at the Brussels PCRU may have busy days with lots of study procedures, as well as rest days with lots of downtime.

For a typical clinical trial at this facility, your busy day will likely start with an overnight fast. You’ll likely wake up early in the morning for pre-dose activities, which could include an electrocardiogram (a test that uses sensors attached to the skin to check your heart’s rhythm and electrical activity), vital signs, and a blood draw. The study doctor will review your results to confirm you may receive the study drug. Staff will administer your dose according to the study requirements – it could be a tablet or capsule by mouth, a liquid that you drink, an injection, a treatment applied to the skin, or other forms. After that, you’ll likely have procedures throughout the day and into the evening, such as blood draws and safety assessments, meals, and monitoring by the staff to see how you’re feeling.

On rest days, you might have a few morning procedures, but when you are not busy with study activities, you can enjoy free time within the PCRU. Within the research unit location, you’ll have access to internet, a large relaxation and reading area, and a multi-media room for entertainment and games.

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Will I have to stay at the PCRU facility the entire time that I’m participating in the clinical trial?

Each clinical study has its own requirements, so the answer to this depends on the study you are participating in. A participant may be required to stay overnight at the PCRU in New Haven, CT, for observation and study procedures. These details are provided in the informed consent document. You may also ask the study team any questions you may have.

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What clinical trials are available at the PCRU? How do I volunteer?

To explore clinical trials happening at the PCRU in Brussels, click Learn More. You may click on a study that interests you and submit the volunteering form at the bottom of the study’s webpage.

You may also call 0800 99 256 (+32 2 556 70 02 from abroad) or click here <link to volunteer form> to see if you may qualify for our clinical research unit’s ongoing clinical trials. All studies have eligibility criteria that you must meet in order to participate. Our recruitment staff will identify what study or studies you might be eligible for.

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Will I be compensated for participating in a clinical trial at the PCRU?

Participants in clinical trials at the PCRU receive financial compensation for their participation. The amount depends on factors like length of the stay, total number of study visits, and the nature of the study procedures.

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What precautions are you taking at the facility in response to the COVID-19 pandemic?

Additional measures have been implemented to protect our clinical trial participants and our team from COVID-19. You will have a temperature check and rapid response COVID-19 test upon entry into our facility. We’ve also implemented mandatory mask use and signage to support physical distancing requirements in the unit. The unit has staffing at all hours and days of the week to clean and sanitize the facility.

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The eligibility criteria for studies at the PCRU include body mass index (BMI). How can I calculate my BMI?

The Centers for Disease Control & Prevention (CDC) provides a calculator that uses your height and weight to determine your BMI. To calculate your BMI, click Learn More.

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What are decentralized clinical trials (DCT)?

In order to prioritize the convenience and comfort of our trial participants, we are beginning to test out options for participation that don’t require volunteers to travel to a specific site or location. This includes things like virtual visits (similar to telehealth), at-home sample and data collection using special devices, and partnering with labs and other businesses to give you more flexibility and let you choose how and where you participate.

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