1.4 Clinical Trials
Clinical trials are research studies that test how well new medical approaches work in people. They follow strict protocols to ensure safety and scientific validity.
Phase I: Safety
20-100
Participants (usually healthy)
1-2 years
Duration
Primary goals: Determine safe dosage range, identify side effects, assess pharmacokinetics. Dose escalation studies, first-in-human.
Phase II: Efficacy
100-500
Patients with target disease
2-3 years
Duration
Primary goals: Assess efficacy, optimal dose finding, expand safety data. Phase IIa (proof-of-concept), Phase IIb (dose-ranging).
Phase III: Confirmation
1,000-5,000
Patients
3-4 years
Duration
Primary goals: Confirm efficacy and safety, compare with existing treatments, gather information for labeling.
Randomized controlled trials (RCTs): Gold standard
Double-blind, placebo-controlled design minimizes bias
Primary and secondary endpoints pre-specified
Phase IV: Post-Marketing
Surveillance after approval to detect rare adverse events, long-term effects, and real-world effectiveness.
Pharmacovigilance
Adverse event reporting, signal detection, risk management.
Real-World Evidence
Effectiveness in diverse populations, long-term outcomes.
Trial Design Principles
Randomization
Random assignment to treatment groups eliminates selection bias.
Blinding
Single-blind (patient), double-blind (patient + investigator), triple-blind (+ assessor).
Statistical Power
Sample size calculation ensures ability to detect clinically meaningful differences.