Clinical research is a branch of medical science that determines the safety and effectiveness of medications, devices, diagnostic products and treatment regimens for humans.
The U.S. National Institutes of Health (NIH) divides clinical research into three main categories:
- Patient-oriented research. Conducted with humans or on material of human origin, such as tissues and specimens. It includes mechanisms of human disease, therapeutic interventions, clinical trials and development of new technologies.
- Epidemiologic and behavioral studies. Examine the distribution of disease, the factors that affect people’s health and how people make health-related decisions.
- Outcomes research and health services research. Endeavor to identify the most effective and most efficient interventions, treatments and services.
Ethical Principles of Clinical Research
The Council for International Organizations of Medical Sciences (CIOMS), an international nonprofit established by the World Health Organization (WHO) and United Nations Educational, Scientific and Cultural Organization (UNESCO), has compiled general ethical principles for clinical research. These principles establish that clinical research involving human subjects should be conducted in accordance with basic ethical principles: respect for persons, beneficence and justice. Respect for persons means recognizing that all individuals should be respected and have the right to choose what treatments they receive; beneficence means protecting people from harm by maximizing benefits and minimizing risks; and justice means ensuring that all people share the benefits and burdens of research equally.
The ethical requirements for clinical research are also codified in the Nuremberg Code, the Declaration of Helsinki, the Belmont Report and various country-specific regulations. They emphasize clinical research volunteers’ safety:
- Subjects must give their informed consent to participate in clinical research and may withdraw at any time
- Clinical research must provide potential benefits to society, though not directly to the subjects
- Experiments must be designed and conducted to avoid injury to subjects
- Clinical research must be separate from medical care
- Ethical committees for clinical research, such as institutional review boards (IRBs) or independent ethics committees (IECs), must review, approve and monitor research involving humans
Clinical Trial Process
Clinical trials assess the safety and efficacy of new therapeutics, vaccines, devices or other interventions. However, before a clinical trial can begin, an investigational drug must be tested extensively in the laboratory to ensure it will be safe to administer to humans. Results of all testing must be provided to the appropriate regulatory agencies in order to obtain permission to begin clinical testing in humans.
Clinical testing is usually described as consisting of Phase I, Phase II and Phase III clinical research studies. In each successive phase, increasing numbers of patients are tested. After the appropriate regulatory agency approves a new drug, pharmaceutical companies may conduct additional studies, including Phase IIIb and Phase IV studies. To learn more about the stages of drug development, visit the About Drug Discovery and Development page.
PPD has successfully conducted clinical research trials in a variety of therapeutic areas since 1985, and our network of clinical trial investigators who work in partnership with our clients has made significant contributions to the advancement of health care.