The role of clinical research

From the lab to market — the phases of a clinical trial

Clinical research plays a pivotal role in advancing knowledge in healthcare – discovering better treatments, more effective devices, or improved procedures, and addressing unmet medical needs.

Clinical research can help advance medical knowledge and improve patient healthcare. It can contribute to the development of potential new drugs, medical devices, and procedures or diagnostic tests, and may provide insights into how diseases are caused and how they may be prevented.

Before a potential new drug or medical device can be introduced into day-to-day medical practice and become available for wider use, it must be granted marketing approval by a regulatory agency. Regulatory agencies require robust evidence of benefits versus risks, and an acceptable safety profile for potential new drugs or procedures tested in clinical trials. Depending on their aim, clinical trials can be divided into 4 phases. 

Phase 1: used to assess if a potential new drug or device is safe and to monitor its effects on the human body.

• Small number of participants (usually a few dozen), often healthy volunteers.
• Typically, several months are needed to complete a Phase 1 trial.

Phase 2: designed to assess how the potential new drug or device influences the current medical condition, to explore possible side effects, and to identify the best recommended dose.

• Phase 2 trials require many more participants than Phase 1 trials (up to several hundred).
• Phase 2 trials can last up to 2 years.

Approximately one-third of the potential new drugs or devices tested in clinical trials complete both Phase 1 and Phase 2.

Phase 3: large-scale trials that assess whether a potential new drug or procedure works better than an existing treatment or standard of care.

• Requires hundreds to thousands of participants.
• Phase 3 trials can take several years to be completed.
• Of those drugs entering Phase 3, approximately 25% to 30% complete this phase.
• Approval certifies that the potential new drug or procedure is effective, has an acceptable safety profile, and can be sold on the market.
• The process of authorizing medicines may adopt a centralized approach, and involve one single regulatory agency, such as the Food and Drug Administration (in the United States) or the European Medicines Agency (in Europe).
• Alternatively, the approval can be issued at the local level via a national authority, valid only at the national level.

Once Phase 3 trials are successfully completed, a pharmaceutical company can collate the findings and submit the results to a regulatory authority for marketing approval.

Phase 4: these trials are performed after a drug has been approved and placed on the market, to collect long-term safety data and generate real-world evidence.

• CenterWatch. Overview of clinical trials.
• Medicines and Healthcare products Regulatory Agency (UK). My medicine: licensing (marketing authorisation).