Clinical trials are meticulously designed to bring innovative therapies, like experimental treatments, to the market. Each phase of the process builds on the results of the previous, ensuring every study drug meets strict safety standards before becoming a standard or experimental drug for patients.

Phases of a Trial

Preclinical Research: Foundation for Success

Before human subjects are involved, researchers conduct preclinical research in labs and animal models. These early research studies assess the potential effectiveness and safety of new drugs or treatments for specific medical conditions.

For example, a study drug targeting heart disease must demonstrate it is safe and effective in animals before advancing to human subjects in clinical trials.

Phase 1: Testing Safety in a Small Group

Phase 1 trials involve a small group of fewer than 100 participants, often healthy volunteers or, in cases like cancer clinical trials, cancer patients. This phase focuses on:

• Identifying safe dosages.

• Monitoring side effects.

• Understanding how the drug interacts with the body.

Only 58% of experimental treatments proceed to the next phase, making this stage critical for determining initial safety.

Phase 2: Exploring Effectiveness

Phase 2 studies recruit 100–500 participants to evaluate whether the experimental treatment works for specific diseases or conditions. These trials often use randomized clinical trials to compare the treatment to a control group or standard treatment.

Common Questions Answered in Phase 2:

• Does the treatment improve the condition?

• Are there unexpected risks or potential benefits?

• What dosage works best for large groups of patients?

This phase also refines protocols for the larger trials to come.

Phase 3: Validating for Large-Scale Use

Phase 3 trials involve large numbers of participants—ranging from 300 to 3,000—ensuring the treatment is effective across diverse patient groups. This phase involves usually randomized trials.

Key objectives include:

• Comparing results to a control group or standard treatment (randomization).

• Monitoring long-term side effects.

• Validating findings for regulatory approval.

Approximately 60% of treatments that reach Phase 3 advance to market, offering new hope to future patients.

Phase 4: Post-Market Monitoring

Once approved, treatments undergo Phase 4 clinical trials to monitor their effectiveness and safety in real-world conditions. These trials often recruit thousands of participants to study long-term impacts and refine dosages for broader populations.

For example, a widely used medical product may require ongoing trials to ensure it meets the evolving needs of health care providers and patients.

Key Features

Clinical trial design ensures that each study generates scientifically valid results. Its design will follow a clinical trial protocol providing key elements to follow during the trial and submitted to the authority (such as the FDA in the United States) before launching the clinical trial.

In the clinical trial protocol, one can find all the following features:

A zoom-in into those elements that are essential to fully understand clinical trials:

• Randomization: Assigns participants to groups to reduce bias.

• Blinding: Prevents participants and researchers from knowing group assignments, maintaining objectivity.

• Control Groups: Compare the experimental drug or treatment against a baseline, such as a placebo.

For instance, a clinical trial protocol might specify:

• Single-blind design: Only participants are unaware of their assignments.

• Double-blind trials: Both participants and researchers (or health care providers) are unaware of groupings.

• Randomized but not blinded trials: Participants know their group assignment but were placed randomly.

What to Expect when Participating

Participating in a clinical trial offers patients access to new treatments while contributing to clinical research. Before joining, review the trial's informed consent document and consider the following:

• Are you eligible based on the trial’s eligibility criteria?

• Do the potential benefits outweigh the risks?

• Does the study drug align with your health goals?

Explore our article on trial eligibility for insights on finding the right trial and navigating the screening process.

In brief

Clinical trials are essential for advancing medicine, ensuring new drugs, medical treatments, and devices meet rigorous standards for safety and efficacy. From preclinical research to Phase III trials and beyond, every trial contributes to better outcomes for future patients.

Whether you’re a participant or a health care provider, understanding the drug development process empowers you to make informed decisions and support innovation in medicine.

At PatLynk, we’re committed to make clinical trials accessible to all. Explore our platform to learn more about clinical trials and to find the right clinical trial for you.