A clinical trial is a type of research study designed to evaluate the safety and efficacy of a new treatment. This treatment can involve various medical, surgical, or behavioural interventions, either individually or in combination.  The scope of clinical trials includes testing new drugs, diets, therapies, or medical devices, and comparing them to already existing treatments (1).

Clinical trials are made up of four distinct phases.

Phase 1 trials primarily assess the safety and optimal administration of a new treatment. Patients are generally divided into smaller groups called cohorts and administered increasing doses of the treatment until the optimal dose is determined.

Phase 2 trials evaluate the efficacy of the treatment for a specific disease, typically involving fewer than 100 patients.

If the results of these trials are promising, Phase3 trials are conducted to compare the new treatment with the standard treatment for the disease. Following a phase 3 trial, the Food and Drug Administration(FDA) or the European Medicines Agency (EMA) reviews the results to decide whether to approve the treatment for general use. ‍

Phase 4 trials are conducted after the treatment has been approved, focusing on studying the long-term side effects and efficacy in the broader population (2, 3).

There are multiple benefits to participating in a clinical trial. It provides researchers with a deeper understanding of your condition,potentially leading to the development of new treatments and preventive measures. Additionally, participation can empower you to take a more proactive stance in managing your own health. You will also have the opportunity to learn more about your specific condition and gain access to support groups and other valuable resources (4).

An example of a highly successful clinical trial is the Phase 2 study titled ‘Study of Induction PD-1 Blockade in Subjects With Locally Advanced Mismatch Repair Deficient Solid Tumors’. In this study the efficacy of dostarlimab, an anti-PD-1 monoclonal antibody, was evaluated for treating mismatch repair-deficient (dMMR) stage II and III rectal cancer.Twelve patients received dostarlimab every three weeks for six months.Remarkably, all patients experienced a complete clinical response with no detectable tumours, requiring no further treatment or surgery. During the follow-up period of 6 to 25 months, no cancer progression or recurrence was observed, and no severe adverse events were reported (5).

Upon enrolling in a clinical trial, the research staff will collect information about you, explain the trial's details, and address any questions you may have. If you agree to participate, you will be required to sign an informed consent form, affirming that you understand the expectations and potential risks involved.  

Following enrolment, you will schedule a baseline visit, during which cognitive and/or physical tests will be conducted to confirm your eligibility for the trial. Depending on the specific trial, you may be randomly assigned to either a treatment group, which will receive the intervention being tested, or a control group.

Throughout the trial, you will follow designated procedures,including regular visits to the research site for evaluations and data collection. These visits are crucial for monitoring your response to the treatment,your overall well-being, and ensuring your safety. Additionally, these visitsprovide opportunities to communicate any concerns with the researchers. Forother healthcare needs, you may maintain regular appointments with your primarydoctor throughout the study (1).

Doctors can recommend clinical trials to their patients if they meet the eligibility requirements. Clinical trial recruitment is regulated by legislation, and advertisements for trials are often disseminated through patient organizations, hospitals, and pharmacies. Additionally, digital media, including dedicated websites, social media, and listings in clinical trial registries are common methods for advertising.

For example, in Norway, the local clinical trial registry HelseNorge provides information on clinical trials and offers a search function for finding ongoing and recruiting clinical trials within the country. Internationally, registries such as ClinicalTrials.gov and ResearchMatch are valuable resources. ClinicalTrials.gov is the largest clinical trial database in the world, allowing users to filter searches for various types of clinical trials focused on different diseases, conditions, and interventions. More information is available on the National Institute of Health (NIH) website (6).

Enrolling in a clinical trial involves a recruitment process that includes screening and obtaining informed consent, both of which are strictly regulated to protect participants and ensure trial integrity. You may discuss with your treating doctor to determine if you fulfil the eligibility criteria for a clinical trial of interest. Subsequently, reach out to the study organizers for further clarification on the trial and to address any questions you might have. It is important that you understand what participation entails by preparing questions about expectations regarding consultations, tests, and protocols. When enrolling, the research team will explain the trial's purpose, duration, risks, benefits, and privacy considerations. It is important to understand the details of the informed consent process. If you agree to participate, you will sign an informed consent form, which confirms your understanding of the study and the potential risks involved. Throughout the trial, you will receive updates on progress and risks associated with the treatment, and you retain the right to withdraw from the trial at any time. This process ensures that you are fully informed and comfortable with your participation in the clinical trial. (7).

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