PHASES OF CLINICAL TRIALS
Clinical trials are conducted in a series of carefully regulated stages, known as Phases, each designed to answer specific research questions and ensure the safety and effectiveness of new treatments.
Phase I – Safety & Dosage
Purpose:
To evaluate the safety of a new treatment and determine the appropriate dosage range.
Participants: A small group (usually 20–80 healthy volunteers or patients across multiple sites).
Focus:
How the body absorbs, distributes, and eliminates the treatment (pharmacokinetics).
Identifying side effects and safe dosage levels.
Often the first time a new drug or device is tested in humans.
Phase II – Efficacy & Side Effects
Purpose:
To assess the treatment’s effectiveness and continue monitoring safety.
Participants: A larger group (typically 100–300 people with the condition being studied across multiple sites).
Focus:
Whether the treatment works as intended.
Short-term side effects or risks.
Helps determine the most effective dose and treatment schedule.
Phase III – Confirmation and Comparison
Purpose:
To confirm effectiveness, monitor side effects, and compare the new treatment to existing standard therapies.
Participants: Large groups (often 1,000–3,000 participants across multiple sites).
Focus:
Establishing broader safety and effectiveness across diverse populations.
Providing data needed for regulatory approval (e.g., by the TGA in Australia).
Often conducted across multiple clinical sites and sometimes internationally.
Phase IV – Post Market Survalence
Purpose:
To monitor the long-term safety and effectiveness of a treatment after it has been approved and is available to the public.
Participants: Thousands of patients in real-world clinical settings.
Focus:
Detecting rare or long-term side effects.
Evaluating long-term benefits and cost-effectiveness.
May lead to updated safety warnings or changes in how the treatment is used.
Each phase is essential in ensuring that new treatments are safe, effective, and suitable for broader use in the community.
At Ophthalmic Trials Australia, we are involved in multiple trial phases with a focus on improving treatments for diseases of the anterior segment of the eye. We have been involved in studies from Phase 1 to 4 over the years of research at our facility.