Module 5

Phases of a clinical trial

1. Phase 0/pre-clinical trial/animal experiment:
   • Not yet applied intervention on human subjects
   • It is pre-clinical stage
   • If it is successful, then phase I follows
2. Phase I/toxicity trial:
   • Done entirely on healthy volunteer
   • Number of volunteer: 20-80
   • We can find response of drug here as we are not dealing with patients
   • Also called toxicity trial
   • Complete study of pharmacokinetic and pharmacodynamics but we focus on toxicity
   • S/E: adverse reactions, safe dose, lethal dose
   • If successful, then go to next phase
3. Phase II/Initial efficacy trial:
   • Healthy volunteers and few patients are enrolled
   • The number can range between 100-200
   • We have healthy volunteer in large number so we can strengthen and rectify finding of phase I
   • Few patients are enrolled so some knowledge of preliminary response of drug
   • If successful, then next step is taken.
4. Phase III/Full scale efficacy trial/Randomized control trial:
   • Entirely patients
   • Patients are randomly divided into two groups: intervention and controlvgroups
   • Since there are two groups we can establish the efficacy of new drug over old drug and over placebo (hence we can make comparison)
   • If the drug is successful, then we can introduce in the market
5. Phase IV trial/Post marketing surveillance:
   • Long term or rare side effects (as phase II and III were done in limited time and small subjects)
   • Whether it is equally showing
   • If post marketing surveillance shows a lot of adverse effects, sometimes the drug is withdrawn if it is not effective.
   • Rosiglitazone and pioglitazone were associated with bladder cancer in long term use
6. Phase V/Re-efficacy trial:
   • By modifying composition drug is re-introduced

While dong RCT, we always have target population in mind.

1. Meta-analysis
2. RCT (correct)

Meta-analysis is only a method of analysis and not a study design.