How New Drugs are Investigated
Pp. 239-244 (6)
Robert E. Smith
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.
The pre-clinical phase is used to prove the scientific principle behind the drug, perform
28 day toxicity studies in two species, identify a suitable formulation, prepare sufficient
material, perform an Institutional Board review, prepare protocols and documents for
Phase I. Phase I measures the absorption, distribution, metabolism and excretion
(ADME) 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. Phases 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 determines the efficacy and find out 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.
Institutional Review Board, absorption, distribution, metabolism and
excretion, ADME, Phase III, clinical trials.
Adjunct Assistant Professor Park University and Consultant Science Advisor United States Food and Drug Administration (FDA) USA