Clinical trials are conducted in a series of STAGES, called phases, each having specific goals. This process provides information about the treatment in a CONTROLLED process intended to also protect the participants. The number of participants in each phase of the trial may be based on the overall incidence of the condition being studied.

Clinical trials are usually classified into one of four phases:

Phase 1: Sometimes called dosing, pharmacokinetic, or clinical pharmacology studies, these trials test methods of ADMINISTERING the treatment (e.g. by mouth, injection, etc.) and how often, as well as the safety of the treatment. These trials usually involve a small number of healthy participants (20-80 healthy volunteers).

Phase 2: These trials continue to test the safety of the treatment and evaluate how well the treatment is tolerated and how well it works. Phase II studies usually evaluate the treatment in a specific condition. These trials usually involve 100-300 patients.

Phase 3: These trials compare the experimental treatment to the current standard of treatment for a specific condition, establishing both efficacy and adverse events. Participants are usually assigned to either receive the experimental treatment or the current standard. Phase III trials typically enroll large numbers of patients (1,000-3,000) and may be carried out at hospitals and doctors’ offices nationwide.

Phase 4: Post-marketing studies to gain a greater understanding of the treatment, including its RISKS, benefits, and optimal use. Depending on the purpose of these studies they may be small studies like the Phase I type OR may be even larger than a Phase III study.

Clinical trials are conducted in a series of stages, called phases, each having specific goals. This process provides information about the treatment in a controlled process intended to also protect the participants. The number of participants in each phase of the trial may be based on the overall incidence of the condition being studied.

Clinical trials are usually classified into one of four phases:

Phase 1: Sometimes called dosing, pharmacokinetic, or clinical pharmacology studies, these trials test methods of administering the treatment (e.g. by mouth, injection, etc.) and how often, as well as the safety of the treatment. These trials usually involve a small number of healthy participants (20-80 healthy volunteers).

Phase 2: These trials continue to test the safety of the treatment and evaluate how well the treatment is tolerated and how well it works. Phase II studies usually evaluate the treatment in a specific condition. These trials usually involve 100-300 patients.

Phase 3: These trials compare the experimental treatment to the current standard of treatment for a specific condition, establishing both efficacy and adverse events. Participants are usually assigned to either receive the experimental treatment or the current standard. Phase III trials typically enroll large numbers of patients (1,000-3,000) and may be carried out at hospitals and doctors’ offices nationwide.

Phase 4: Post-marketing studies to gain a greater understanding of the treatment, including its risks, benefits, and optimal use. Depending on the purpose of these studies they may be small studies like the Phase I type OR may be even larger than a Phase III study.