There are four major phases in a clinical trial.

Phase I : Human Pharmacology Trials

Phase II : Therapeutic exploratory trials

Phase III : Therapeutic Confirmatory Trials

Phase IV : Post marketing Surveillance Trials

There are different phases of CT

Pre Clinical Studies: They involve in-vitro studies and in-vivo studies on animals. Wide ranging doses are given to animals and the PK, efficacy and toxicity PARAMETERS are studied to determine the viability of further studies. 

Phase 0: Human Micro DOSING Studies (normally the doses are 100 times less than the intended therapeutic doses). Single sub therapeutic doses are administered to a small number of subjects (10-15) PK and PD parameters are derived.Gives no data on safety or efficacy. To support basic go/no go decision making.

Phase I: Human Pharmacology Trials. Size - 20 to 80. May range from several months to a year Usually to TEST one or more of

combination of objectives.

1. Maximum tolerated dose

2. PK

3. PD

4. Early measurement of Drug activity

This phase also includes SAD, MAD and FOOD EFFECT studies.

Phase II:Therapeutic exploratory trials to determine the effective dose and the dosing regimen.May last from 1 to 2 years.Conducted after safety of the drug is confirmed in phase I. Sample size is larger, between 20-300 Sometimes divided into Phase IIA To assess Dosing requirements. Phase IIB to study efficacy.

Phase III: Therapeutic confirmatory trials are randomized, controlled, multicentered trials. Also called pivotal trials because they are crucial to the approval of the drug. May last from 3 to 5 years. Aimed at being definitive assessment of effectiveness of drug in comparison with the current gold standard treatment Sample size 300 – 3000

Phase IV: Post marketing surveillance studies. Either required by the regulatory authorities or UNDERTAKEN by the manufacturer for competitiveness To gather information like use of Drug in children Pregnant women, children Elderly patients Patients with renal or other failures Specific concomitant

There are four major phases in a clinical trial.

Phase I : Human Pharmacology Trials

Phase II : Therapeutic exploratory trials

Phase III : Therapeutic Confirmatory Trials

Phase IV : Post marketing Surveillance Trials

There are different phases of CT

Pre Clinical Studies: They involve in-vitro studies and in-vivo studies on animals. Wide ranging doses are given to animals and the PK, efficacy and toxicity parameters are studied to determine the viability of further studies. 

Phase 0: Human Micro Dosing Studies (normally the doses are 100 times less than the intended therapeutic doses). Single sub therapeutic doses are administered to a small number of subjects (10-15) PK and PD parameters are derived.Gives no data on safety or efficacy. To support basic go/no go decision making.

Phase I: Human Pharmacology Trials. Size - 20 to 80. May range from several months to a year Usually to test one or more of

combination of objectives.

1. Maximum tolerated dose

2. PK

3. PD

4. Early measurement of Drug activity

This phase also includes SAD, MAD and FOOD EFFECT studies.

Phase II:Therapeutic exploratory trials to determine the effective dose and the dosing regimen.May last from 1 to 2 years.Conducted after safety of the drug is confirmed in phase I. Sample size is larger, between 20-300 Sometimes divided into Phase IIA To assess Dosing requirements. Phase IIB to study efficacy.

Phase III: Therapeutic confirmatory trials are randomized, controlled, multicentered trials. Also called pivotal trials because they are crucial to the approval of the drug. May last from 3 to 5 years. Aimed at being definitive assessment of effectiveness of drug in comparison with the current gold standard treatment Sample size 300 – 3000

Phase IV: Post marketing surveillance studies. Either required by the regulatory authorities or undertaken by the manufacturer for competitiveness To gather information like use of Drug in children Pregnant women, children Elderly patients Patients with renal or other failures Specific concomitant