Joining clinical trials

The purpose of a clinical trial

Clinical trials look for ways to treat diseases better. Volunteers receive a medicine or method chosen by the researchers. In this way, researchers learn what it does in people. In some trials, a new treatment is compared with an existing treatment. The person taking part may or may not benefit personally.

Source: ClinicalTrials.gov – Learn About Studies · MedlinePlus – Clinical Trials · TİTCK Klinik Araştırmalar Portalı – Vatandaş İçin

Phases: trials that move forward step by step

New medicines are tested in several stages, called phases, one after another. Each phase looks for the answer to a different question. A medicine does not move on to the next phase until it has passed the previous one.

1. Phase 1: The medicine is tested for the first time in a small number of people. Safety, side effects and the right dose are studied.
2. Phase 2: The medicine is tested in more patients. Its effect and safety are monitored more closely.
3. Phase 3: In larger groups of patients, it is compared with an existing treatment or with a placebo.
4. Phase 4: After the medicine is approved, it continues to be monitored in everyday use. This is not done for every medicine.

Source: NHS – Clinical trials · Beşeri Tıbbi Ürünlerin Klinik Araştırmaları Hakkında Yönetmelik, md. 4 (Faz I–III tanımları) (mevzuat.gov.tr)

Placebo, random assignment and blinding

A placebo is a product that looks like the medicine but contains no active substance. In most trials, people are divided into groups at random, that is, by chance. This is usually done by a computer. Neither you nor your doctor can choose the group. In some trials, neither you nor the team knows who is in which group. This is called blinding. The aim is to assess the results fairly.

Source: ClinicalTrials.gov – Learn About Studies · NHS – Clinical trials

An experimental treatment is not a proven treatment

The medicine tested in a trial has often not yet been approved. Often, the researchers do not know whether the medicine is helpful, harmful or the same as the existing treatment. That is why the trial is carried out. Testing a medicine does not mean that it will work. It is important to see a trial as research, not as a door to hope.

Source: ClinicalTrials.gov – Learn About Studies · NHS – Clinical trials

Ethics committee approval and TİTCK authorization

A medicine trial cannot start without ethics committee approval and authorization from the Türkiye İlaç ve Tıbbi Cihaz Kurumu (TİTCK, Turkish Medicines and Medical Devices Agency). An ethics committee is an independent committee set up to protect the rights and safety of volunteers. You can ask the team whether the trial offered to you has received these approvals.

Source: Beşeri Tıbbi Ürünlerin Klinik Araştırmaları Hakkında Yönetmelik, md. 4 ve md. 11 (mevzuat.gov.tr) · TİTCK Klinik Araştırmalar Portalı – Vatandaş İçin

The informed consent form for volunteers

Before you take part, the researcher must explain the trial to you in a way you can understand. The aim, the method, the expected benefits, the possible risks and the difficulties are explained. You are also told about your right to withdraw. You must be given enough time to ask questions and to decide. Consent is given in writing. You read the form, date it and sign it. You must decide of your own free will, without being given any advantage.

1. Ask whether you can take the form home and talk it over with your family or your doctor.
2. Ask them to explain every term you do not understand.
3. If you are not able to sign, the discussion takes place in front of an impartial witness who is not part of the team.
4. A copy of the form must be given to you or to your legal representative.

Source: Beşeri Tıbbi Ürünlerin Klinik Araştırmaları Hakkında Yönetmelik, md. 20 ve md. 21 (mevzuat.gov.tr)

You can withdraw at any time

You can leave the trial at any moment. You do not have to give a reason. Leaving does not make you lose any of your rights in your further treatment. Your rights in your medical follow-up are also protected. Talk to the team before you leave. This way, you can do it safely. A researcher is also appointed to give you information throughout the trial.

Source: Beşeri Tıbbi Ürünlerin Klinik Araştırmaları Hakkında Yönetmelik, md. 20 (mevzuat.gov.tr) · ClinicalTrials.gov – Learn About Studies

Children: parental consent and the child’s own say

In trials involving children, written consent is obtained from the mother and the father, or from the guardian if there is a guardianship. If the child is able to make a decision, the child’s agreement is also obtained. Information about the trial is explained to the child in a way that suits their age. If the child does not want to take part, or later wants to withdraw, the child is taken out of the trial. If the child reaches the age to give consent while the trial is ongoing, consent is also obtained from the child. The ethics committee cannot give its approval without a favorable opinion from a pediatrician.

Source: Beşeri Tıbbi Ürünlerin Klinik Araştırmaları Hakkında Yönetmelik, md. 10 ve md. 23 (mevzuat.gov.tr)

Costs, payment and insurance

You cannot be asked to pay for the trial medicine, the necessary supplies, examinations, tests or treatments. No one may make you a persuasive offer of money to take part, either. However, costs arising from your participation, such as travel costs, are covered by the research budget. Insurance for volunteers is mandatory. Only low-risk scientific studies are exempt from this. Signing the consent form does not take away your right to claim compensation if you are harmed.

Source: Beşeri Tıbbi Ürünlerin Klinik Araştırmaları Hakkında Yönetmelik, md. 20, md. 53 ve md. 54 (mevzuat.gov.tr) · TİTCK Klinik Araştırmalar Portalı – Vatandaş İçin

Your personal data

Your privacy is protected by law. The Kişisel Verilerin Korunması Kanunu (Personal Data Protection Law) applies here. If the results are published, your name cannot be disclosed. Your data may also be used in other research in the future. Your separate permission must be obtained for this. You can withdraw this permission at any time. But data already used before then is not affected.

Source: Beşeri Tıbbi Ürünlerin Klinik Araştırmaları Hakkında Yönetmelik, md. 20 (mevzuat.gov.tr)

Talk to your doctor and to patient associations

The first step is to ask the doctor who follows your care. Your doctor may know whether there is a suitable trial. Patient associations may also announce trials related to their disease. Even if you find a trial on the internet, talk to your doctor before deciding.

Source: NHS – Clinical trials · ClinicalTrials.gov – Learn About Studies

TİTCK Klinik Araştırmalar Portalı (KAP, Clinical Trials Portal)

TİTCK (Turkish Medicines and Medical Devices Agency) publishes the records of clinical trials in Türkiye on a public portal. On the portal, you can search by disease name, by center and by trial status. You can also see whether volunteers are still being recruited. The portal contains trials applied for in 2016 or later. Some older, completed trials are not included. The portal is for information only; the official record is held by the Agency.

Source: TİTCK Klinik Araştırmalar Portalı (KAP) · TİTCK – Klinik araştırma arama ekranı · Beşeri Tıbbi Ürünlerin Klinik Araştırmaları Hakkında Yönetmelik, md. 57 (mevzuat.gov.tr)

ClinicalTrials.gov

ClinicalTrials.gov is a registry website run by the US National Library of Medicine. The site is in English. It lists trials from many parts of the world. Each trial has an NCT number. It states who can take part, where the trial is carried out and whether it is recruiting volunteers. The information is entered by those running the trial. The US government does not review the safety of every trial on the list. Being on the list does not mean that a trial is safe or effective.

Source: ClinicalTrials.gov – Learn About Studies · ClinicalTrials.gov – Disclaimer · MedlinePlus – Clinical Trials

European Union registries and the WHO platform

Medicine trials in the European Union can be searched on the Clinical Trials Information System (CTIS) website of the European Medicines Agency. This site contains trials after 31 January 2022. For older trials, there is the EU Clinical Trials Register. The World Health Organization’s ICTRP platform shows the registries of many countries in one place.

Source: Clinical Trials in the European Union (euclinicaltrials.eu – EMA) · EMA – Clinical trials in human medicines · NHS – Clinical trials

Inclusion and exclusion criteria

Each trial looks for certain people. Criteria may include age, sex, the type of disease or treatments received before. These criteria are there both to protect the volunteer and to answer the research question correctly. Not being accepted into a trial is not a judgment about you.

Source: ClinicalTrials.gov – Learn About Studies · MedlinePlus – Clinical Trials

Screening visits

When you show interest in a trial, a doctor or nurse explains the trial to you. You are also given written information. To find out whether you are eligible, visits and tests called screening may be done. Even after screening, you may not be accepted into the trial.

Source: NHS – Clinical trials · ClinicalTrials.gov – Learn About Studies

Visits, tests and travel

In a trial, you may need to go to the hospital more often than in normal follow-up. More tests may be done. You may be asked to fill in questionnaires or keep a diary. Some trials require staying overnight at the center. Sometimes you may be asked to stop other medicines. Think from the start about what the travel and time off work would mean for you.

Source: NHS – Clinical trials · ClinicalTrials.gov – Learn About Studies

Long-term follow-up and when the trial ends

A trial may last a few days or many years. The team may want to follow you for some time even after treatment ends. When the trial ends, the results must be published. If you want to know the results, ask the team. Also ask from the start what will happen to the medicine when the trial ends. The early access guideline of TİTCK (Turkish Medicines and Medical Devices Agency) states that patients who benefit from the treatment after a trial can be included in these programs.

Source: ClinicalTrials.gov – Learn About Studies · NHS – Clinical trials · TİTCK – İnsani Amaçlı İlaca Erken Erişim Programı Kılavuzu (19.01.2023 revizyonu)

Side effects

During the trial, you may have side effects or another health problem. Some side effects may not be known in advance. The team should explain what to do if a problem occurs. Report problems to the team right away. Researchers are required to record adverse events seen in volunteers. If a serious problem occurs, the trial may be stopped.

Source: ClinicalTrials.gov – Learn About Studies · Beşeri Tıbbi Ürünlerin Klinik Araştırmaları Hakkında Yönetmelik, md. 29 (mevzuat.gov.tr)

There is no guarantee of benefit

The new treatment may not turn out better than the existing treatment. It may even be worse. The person taking part may not benefit personally. Some people take part to contribute to science and to future patients. Others take part for the chance to access a treatment that has not yet been approved. Both reasons are understandable.

Source: NHS – Clinical trials · ClinicalTrials.gov – Learn About Studies

You may be in the placebo group

In randomized trials, you may not receive the medicine being tested. Instead, you may receive standard treatment or a placebo. A placebo is usually used when there is no proven standard treatment. You may not know which group you are in during the trial. Discuss this possibility with the team before taking part.

Source: NHS – Clinical trials · ClinicalTrials.gov – Learn About Studies

For those who cannot join a trial: early access for humanitarian purposes

In some people with severe disease, existing treatments do not work. These people may also not be able to join a trial. In this case, the early access program for humanitarian purposes of TİTCK (Turkish Medicines and Medical Devices Agency) may be an option. In this program, a medicine that is not licensed in Türkiye is provided free of charge by the company that developed it. This program is not a clinical trial. There is not a program for every medicine. Your doctor decides whether you are eligible.

Source: TİTCK – İnsani Amaçlı İlaca Erken Erişim Programı Kılavuzu · TİTCK – İnsani Amaçlı İlaca Erken Erişim Programı Kılavuzu (PDF, 19.01.2023 revizyonu) · EMA – Compassionate use

Each country has its own rules

A trial abroad is conducted under the rules of that country. Rules vary from country to country. Taking part in a trial from another country is often not prohibited. But usually each application is assessed individually. First, find out whether the trial accepts volunteers from abroad.

Source: ClinicalTrials.gov – Learn About Studies · ACT EU – Making cross-border access to clinical trials a reality (EU-X-CT sunumu, 2025)

Costs, language and follow-up after you return

In cross-border participation, the hardest question is who pays for what. Some trials cover travel and accommodation costs; others do not. Language can make it harder to understand the risks. Ask for the information in a language you understand. Also discuss from the start how your follow-up will be done when you return to your country and where the insurance covers you. Keep your doctor informed during this process.

Source: ACT EU – Making cross-border access to clinical trials a reality (EU-X-CT sunumu, 2025) · ClinicalTrials.gov – Learn About Studies · NHS – Clinical trials