New drugs are investigated in the following steps: pre-clinical, phase I, phase
IIa, phase IIb, phase IIIa, phase IIIb, launch new FDA-approved drug and phase IV,
post market surveillance [1]. The pre-clinical phase is used to prove the scientific
principal behind the drug, perform 28 day toxicity studies in two species, identify a
suitable formulation, prepare sufficient material, perform an Institutional Review Board
review, and prepare protocols and documents for Phase I. Phase I measures the
absorption, distribution, metabolism and excretion (ADME) [1] safety and tolerability
in healthy human subjects, except in emergencies, such as treating terminally ill cancer
patients for whom all standard therapies have been tried already. Phase IIa tests the
efficacy of the IND and its ADME in patients and IIb establishes the dosage and
regimen for Phase III. Phase III is the large scale clinical trial that will determine the
efficacy and look for side effects. After getting FDA approval and launching the new
drug, the market must be monitored so that all side effects and complaints are saved and
studied. Also, additional applications for the drug might emerge as it is used on patients
with more than one condition that needs to be treated.
Keywords: Institutional Review Board, absorption, distribution, metabolism and
excretion, ADME, Phase III, clinical trials.
