Phase I
Upon IND approval by the FDA, an experimental drug may then enter a Phase I trial. Phase I trials are “first in human” trials where the main purpose is safety assessment. After IRB approval, a Phase I trial may be conducted at an academic medical center’s General Clinical Research Center (GCRC) and enroll 15-20 patients. GCRCs are 24-hour monitoring facilities that employ clinical research coordinators/nurses and pharmacology scientists focused on translational medicine (translating basic science research into clinical applications). The second purpose of a Phase I trial is to study pharmacokinetics, how the drug is processed by the human body, such as absorption, distribution, metabolism and excretion (ADME).
The third purpose of Phase I study is dose escalation. Dose escalation may discover the dose limiting toxicity (DLT) based upon the discovery of side effects. Drug side effects are graded 1-5, from mild to severe. Grade 3 typically means that the drug was held due to a moderate side effect. Grade 4 means the side effect was more serious or needed a hospital visit. The maximal tolerated dose (MTD) is often determined by the dose reached when the first two patients on a phase I trial develop a DLT. Usually the DLT is reversible or wears off without lasting effects.
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