What Is a Clinical Trial

What Is a Clinical Trial

A study conducted in humans to verify safety and efficacy — an essential step in developing new drugs.

A clinical trial is a test or study conducted in human subjects to prove the safety and efficacy of a drug before it is developed and marketed, examining the drug's distribution, metabolism, and excretion in the body, its pharmacological and clinical effects, and its side effects.

An investigational drug whose safety and efficacy have been verified through clinical trials then receives manufacturing approval from the health authorities, leading to the development of a new drug.

Phases of a Clinical Trial

A new drug is developed through the following six-stage verification process.

STEP 1
  • Discovery & Screening of New Substances
    After setting development goals, candidate compounds are synthesized in the laboratory or extracted from nature.
STEP 2
  • Non-clinical (Preclinical) Testing
    The candidate compound developed in the laboratory is administered to animals to screen for safety and efficacy and to estimate the dosage range for humans.
STEP 3
  • Phase I Clinical Trial
    The candidate compound is administered to humans (healthy volunteers) for the first time to confirm safety, efficacy, and dosage.
STEP 4
  • Phase II Clinical Trial
    In 100–300 patients with the relevant mild condition, the drug's efficacy is established and finally confirmed through long-term observation over 2–3 years.
STEP 5
  • Phase III Clinical Trial
    In 1,000–5,000 patients with the relevant condition, the drug's efficacy is established and finally confirmed through long-term observation over 2–3 years.
STEP 6
  • Phase IV Clinical Trial
    Research to collect real-world data on the efficacy, safety, and side effects of the approved and marketed new drug and to determine its optimal use.
After launch, the developed drug undergoes continuous post-marketing surveillance to steadily accumulate data, establishing itself and contributing to human welfare and health.