The purpose of a clinical trial is to answer a clinical question related to the safety and efficacy of a novel or existing treatment, procedure, or device. Based upon the results of the study, a clinical trial aims to bring new knowledge to the scientific community by better understanding the effects and consequences of an intervention. New treatments are tested in clinical trials before being made available to patients.
Types of clinical trials
Different types of clinical trials exist to analyze and answer specific questions. They can evaluate treatments, disease prevention, quality of life, diagnostic and screening interventions1.
Depending upon the information provided to participants and known by the clinical trial team, clinical trials can be divided into:
Randomized controlled trials: Participants are randomly assigned to a specific group (e.g., experimental or control) which will receive the medical intervention or the standard of care or if the placebo (also referred to as the inactive drug) if no standard of care exists. The standard of care refers to the medical treatment or intervention that is commonly accepted and used by healthcare professionals to manage and treat a particular medical condition. In a clinical trial, the standard of care is compared to the novel medical intervention being tested.
Different types of randomized controlled trials exist depending on the information known by the participants and the members of the research team regarding treatment administration (e.g., in which group participants are).
Blinded: Clinical trials are commonly conducted in a "blinded" manner where patients and clinical trial supervising doctor are unaware if they are getting the investigational treatment or placebo. The placebo effect is a natural phenomenon observed when a patient knows if he or she is in the experimental (e.g., that receives the novel treatment) or control group (e.g., that receives the placebo or unactive medication or standard of care). By knowing one’s group in advance, the patient’s response to the medical intervention is unconsciously or consciously affected. The results are thus psychologically influenced and do not appropriately reflect the performance of the treatment alone.
Open-label studies: In some cases, it may not be possible to hide from patients which group they belong to (e.g., experimental or control) in a clinical trial. For instance, if a study involves testing the efficacy of a procedure, participants in different groups will receive different interventions, making it evident which group they are in. Open-label studies can also be referred as “unmasked” or “unblinded” studies.
Phases of clinical trials:
In the case of the development of a novel drug, vaccine or treatment, clinical trials are used to assess the safety and efficacy of the medical intervention. Before testing a novel intervention on humans in a clinical trial, it is typically studied for several years in preclinical studies on animals or in laboratory settings to evaluate its safety and effectiveness. Phases of a clinical trial are listed in order from 1 to 4. Following phase 3, a novel drug treatment can be submitted for approval by a regulatory body (e.g., Health Canada in Canada).
Please note that the following information provided on clinical trials is based on the typical scenario, and for rare diseases, the number of participants and phases may differ or be combined.
Phase 1: the number of participants involved is between 10 to 100. The purpose of this phase is to determine the effects of a medical intervention on healthy individuals. The effects of a medical intervention include its impact on the human body such as its efficacy and safety. Phase 1 studies are the first time the intervention is used in humans. Given the first exposition to humans, only a small sample of healthy individuals assess the appropriate dosage, side effects and safety profile associated with the intervention.
Phase 2: the number of participants involved is between 50 to 500. Participants are individuals who live with a specific medical condition that is under study and who may potentially benefit from the medical intervention are. The purpose of this phase is to assess the efficacy, safety, and appropriate dosage of the treatment/intervention.
Phase 3: the number of participants involved is typically in the 1000s. Individuals who will benefit from the treatment are involved in this phase. The main purpose is to assess the efficacy of the treatment on many thousands of participants. Multiple studies of this phase are required to obtain approval by regulatory bodies.
Phase 4 (post-approval): post-approval refers to the period after a treatment/intervention has been approved by a regulatory agency and is now available to patients for use in clinical practice. During this phase also referred as post-marketing, data is collected to evaluate the long-term safety and effectiveness of the treatment in real-world settings. The treatment effectiveness, safety profile and side effects are reported in this phase among different types of populations.
Monitoring and safety:
Running a clinical trial requires the collaboration of different groups of people who monitor the study and aim to ensure participants’ safety and health.
Principal investigator is the person who leads the study. They are healthcare providers with experience in research and in clinical practice with the disease studied. They are responsible for the safety of all the patients and adhering to Good Clinical Practice.
Study coordinators* manage administrative tasks and delegated clinical tasks. They are responsible for interacting with participants, corresponding with external parties, and reporting to the principal investigator and regulatory authorities.
Study physicians* can administer the medical intervention to patients. They ensure patient follow-up and monitor health status throughout the study. They report any side effects or health issues.
Study nurses* can be involved in patient recruitment and in patient care by providing medical interventions and guidance to patients.
Biostatisticians and data managers are responsible to collect, analyze and interpret data.
*Note that coordinators, physicians and nurses can all administer medication if delegated to do so.
Clinical trials are monitored by independent entities to ensure patient safety, respect of study protocols and ethical practices along the process.
Among these entities, Research Ethics Boards approve the study by reviewing the protocol, its safety, potential benefits over risks, and respect of ethics. Ethic committees are composed of healthcare professionals, researchers, lawyers and community members. They also approve following protocol modifications.
The sponsor is the entity (e.g., a company or contract research organization, academic organizations, research groups) which is responsible for the overall conduct of the trial. The sponsor provides the financial and material resources to accomplish the clinical trial.
Regulatory authorities such as Health Canada set and enforce health standards. Health Canada reviews and approves studies, as well as other regulatory submissions related to authorization. It plays a critical role in ensuring that clinical trials meet rigorous standards and are conducted safely and ethically.
Results and outcomes
How are clinical trials used to improve patient care?
Clinical trials are crucial evidence-based studies that enable the development and distribution of novel treatments and medical interventions to patients and the general population. They represent a high level of trusted scientific evidence and proof due to the rigorous structure followed to obtain valid results. Clinical trial results help physicians and healthcare professionals to better treat patients with up-to-date information in clinical practice.
Future of clinical trials
Psoriasis and arthritis psoriasis clinical trials aim to develop and evaluate new medications to treat patients, manage their symptoms and enhance their overall quality of life. The results of clinical trials have an impact on physicians’ clinical decision making. Therefore, it is essential to have a diverse group of participants in these trials to ensure that the treatment is safe and effective for all patients, regardless of their age, gender, ethnicity, disease severity, or overall health status. The involvement of participants in clinical trials is crucial for the advancement of medical knowledge and the development of new treatments/medical interventions that can improve patient care.