Phase I | Phase II | Phase III
Also see Expanded Access
Phase I trials - designed primarily to evaluate drug safety and dosing on relatively small number of patients.
Tests newest drug candidates for first time in humans.
Because of limited experience in patients there is more inherent risk.
However, patients are closely monitored for adverse reactions and doses are slowly increased to reduce risks to the participants.
May be most appropriate for patients with disease that is refractory (resistant) to standard treatments.
Increasingly new drug candidates are more specific to a defect in the cancer cell, and therefore potentially less toxic. This trend might reduce the inherent risks of phase I studies overall, but not necessarily for a specific drug.
Phase II trials - designed to assess a drug's efficacy, risks, side effects, and optimal dose in a larger number of patients for the indicated condition.
Better understood than phase I drugs, but still not without risks and uncertainty about potential to provide clinical benefit.
Based on the data from phase II studies, the drug sponsor will decide if phase III studies are indicated, and what the design of the phase III study should be in order to definitely demonstrate that the drug has clinical benefit.
Phase III trials -designed to definitely establish if the new drug has clinical benefit by comparing it to a standard treatment (the control).
Phase III studies typically includes a large number of patients randomly assigned to one of two treatment arms - the control or the investigational agent - in order to evaluate the new agent without bias.
The data from phase III studies provides additional information on safety and efficacy, which will be included in the product's labeling if the drug is approved for marketing.
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