Clinical Research & Clinical Trials

In order to obtain marketing approval for any new drug or pharmaceutical medicinal product in the USA, EU, Canada, and most of the countries around the globe, a wide range of appropriate pharmacology and toxicology testing in humans with various phases needs to be conducted involving both patients as well as healthy subjects, these are termed as CLINICAL TRIALS. Clinical trials are also known as Interventional studies.


Clinical research involving worldwide clinical trials for new drugs or investigational medicinal products  is divided into 4 phases of a clinical trial:

Phase 1 Clinical Trials:

Area of study: Human pharmacology

Duration of study: few months to 1 year

No. of subjects: 20 to 80

Type of subjects: Healthy volunteers

Trial design: Simple and open-label clinical trials/open-label studies

Phase 1 clinical trials are the foremost stages in determining the safety profile of drug effects in humans. They are designed mainly to find the maximum tolerated dose and the pathways. The major objective of phase 1 clinical trials are meant to examine the absorption, distribution, metabolism, and excretion (also known as ADME studies) as well as safety and toxicity.


Phase 2 Clinical Trials:

Area of study: safety & efficacy

Duration of study: few months to 2 years

No. of subjects: 100 to 300

Type of subjects: Patients

Trial design: Double-blinded clinical trials

Phase 2 clinical trials are usually performed in patients suffering from the disease for which the drug was originally developed. Phase 2 clinical trials are carried out for analyzing the efficacy and safety profiles of the medicinal product. The major objective is to find out the minimal effective dose that encloses efficacy with the minimum of AEs. 


Phase 3 Clinical Trials:

Area of study: Risk-benefit ratio

Duration of study: 3 to 4 years

No. of subjects: 300 to 3000

Type of subjects: Special treatment groups (geriatrics/pediatrics/pregnant women/lactating mothers).

Trial design: Randomized-controlled clinical trials

Phase 3 clinical trials are usually the key (the old term is “pivotal”) studies to be submitted for regulatory approval, and they are incorporated in the NDA submission or “MA  dossier.” Whereas Phase 3 clinical trials generally focus on pharmacoeconomic or risk evaluation issues as well as cost-effectiveness and studies against competitor drugs. Mostly astonishing or unexpected outcomes are seen in this phase.


Phase 4 Clinical Trials:

Area of study: Risk Evaluation and Mitigation Strategies (REMS) 

Duration of study: minimum 2 years

No. of subjects: 10,000 to lakhs

Type of subjects: patients

Trial design: Variable (ranging from small open-label trials to massive, multicenter, double-blind clinical trials)

Phase 4 clinical trials are post-marketing trials or pharmacoeconomic studies meant to provide head-on comparisons with competitor drugs. Phase 4 clinical trials are conducted for specific safety reasons to investigate an AE or a signal that has unexpectedly occurred after marketing. These may be classical clinical trials or observational or epidemiologic studies performed over larger population databases.


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