Clinical Trials
Introduction
Clinical trials are research studies performed in people that are aimed at evaluating a medical, surgical, or behavioral intervention. They are the primary way that researchers find out if a new treatment, like a new drug or diet or medical device (for example, a pacemaker) is safe and effective in people.
History
Clinical trials have a long history, dating back to the ancient times. The first recorded clinical trial was conducted by the Persian physician Avicenna (Ibn Sina) in 1025 AD, when he introduced experimental medicine and clinical pharmacology.
Types of Clinical Trials
Clinical trials are classified into two main types: interventional studies and observational studies.
Interventional Studies
In an interventional study, the investigators give the research subjects a particular medicine or other intervention. Their results are then compared with those of the subjects who receive no treatment or standard treatment.
Observational Studies
In an observational study, the investigators observe the subjects and measure their outcomes. The investigators do not actively manage the study.
Phases of Clinical Trials
Clinical trials of new drugs are usually conducted in a series of steps, called phases. Each phase is designed to answer a separate research question.
Phase I
Phase I trials are the first stage of testing in human subjects. Normally, a small (20-80) group of healthy volunteers will be selected. This phase includes trials designed to assess the safety (pharmacovigilance), tolerability, pharmacokinetics, and pharmacodynamics of a drug.
Phase II
Phase II trials are performed on larger groups (100-300) and are designed to assess how well the drug works, as well as to continue Phase I safety assessments in a larger group of volunteers and patients.
Phase III
Phase III studies are randomized controlled multicenter trials on large patient groups (300–3,000 or more depending upon the disease/medical condition studied) and are aimed at being the definitive assessment of how effective the drug is, in comparison with current 'gold standard' treatment.
Phase IV
Phase IV trial is also known as postmarketing surveillance Trial. Phase IV trials involve the safety surveillance (pharmacovigilance) and ongoing technical support of a drug after it receives permission to be sold.
Design of Clinical Trials
Designing a clinical trial involves several important considerations, including defining the study objectives, selecting the study population, determining the trial design and choosing the statistical methods.
Study Objectives
The study objectives are the specific goals that the trial is designed to achieve. These can include assessing the safety and efficacy of a new drug or device, comparing different treatment options, or studying the natural history of a disease.
Study Population
The study population refers to the group of individuals who will be recruited to participate in the trial. This can include patients with a specific disease, healthy volunteers, or other groups, depending on the study objectives.
Trial Design
The trial design refers to the overall structure of the trial, including the number of participants, the duration of the study, the measures that will be used to assess the outcomes, and the statistical methods that will be used to analyze the data.
Statistical Methods
Statistical methods are used to analyze the data collected during the trial. These methods can include descriptive statistics, inferential statistics, and survival analysis, among others.
Ethics in Clinical Trials
Ethical considerations are extremely important in clinical trials. All clinical trials must be approved by an ethics committee before they can begin, and all participants must give informed consent before they can participate.
Ethics Committee Approval
Before a clinical trial can begin, it must be approved by an ethics committee. This committee is responsible for ensuring that the trial is ethical and that the rights and welfare of the participants are protected.
Informed Consent
Informed consent is a process in which a potential participant is given information about the trial, including its purpose, duration, required procedures, risks and potential benefits, alternative treatments, and rights as a participant. The potential participant must then give their voluntary agreement to participate.
Regulation of Clinical Trials
Clinical trials are regulated by a variety of national and international organizations, including the Food and Drug Administration (FDA) in the United States, the European Medicines Agency (EMA) in Europe, and the World Health Organization (WHO).
Food and Drug Administration (FDA)
In the United States, the FDA is responsible for regulating clinical trials. The FDA sets the standards for how clinical trials are conducted and ensures that the rights, safety, and well-being of participants are protected.
European Medicines Agency (EMA)
In Europe, the EMA is responsible for the scientific evaluation, supervision and safety monitoring of medicines in the European Union.
World Health Organization (WHO)
The WHO also plays a role in the regulation of clinical trials worldwide. The WHO provides guidance and technical support to countries in developing and implementing policies and regulations related to clinical trials.