Selecting Clinical Candidates for Trial

Once a company has selected its clinical candidate, it has to be made in bulk—in hundreds of kilogram quantities, which itself is not trivial, to prepare for entering clinical trials. It is important to understand the significance of the sequence of phases in clinical trials. The stages are  

The stage of drug development in which drug safety is determined in a small group of 20-40 healthy volunteers cost 1 million Phase 11 (A B) 

The stage in which large-scale safety and effectiveness are ascertained is as many as 20,000 patients cost 200-300 million Phase IV 

The later nonobligatory stages where approved drugs are tested against new indications for an extension of the prescription labeling 

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