| Preclinical Studies –
Before testing an experimental drug in humans, extensive preclinical testing must be
completed to establish initial parameters for safety and efficacy. Preclinical animal
testing establishes a mechanism of action for the drug, its bioavailability, absorption,
distribution, metabolism, and elimination through studies performed in animals. Animal
studies are used to assess whether the drug will provide the desired results. Varying doses
of the experimental drug are administered to test the drug's efficacy, identify harmful
side-effects that may occur, and evaluate toxicity.
IND – If preclinical testing shows that the experimental drug possesses the expected biological activity in laboratory and animal studies, the company will file an Investigational New Drug (IND) application with the FDA in order to begin human studies. The IND application contains the results of preclinical testing, the chemical structure of the compound, how it is thought to work, toxic and side effects revealed in the animal studies, and how the compound is manufactured. The IND also describes the company's plans for human trials including how many participants the study will involve, the criteria for enrolling patients, where and how the studies will take place, and how safety and efficacy will be measured. If the FDA accepts the IND, studies using human subjects can begin within 30 days. Phase I – Phase I clinical trials are primarily designed to examine the safety of an experimental drug. This phase requires approximately one year and involves 20-100 healthy volunteers. The various tests used in this phase enable development of the drug's safety profile and the safe dosage range. The studies also determine how the drug is absorbed, distributed in the body, metabolized, excreted, and the duration of its action. Further trials cannot take place unless Phase I results show the drug to be reasonably safe when administered to humans. Phase II – Phase II trials usually require 100-300 individuals who suffer from the disease or condition the experimental drug is intending to treat. The objectives of this phase are to confirm safety, determine efficacy in humans over a short period of time, and to determine effective dosage levels. Phase II trials are typically double-blinded and placebo-controlled to prevent expectations from influencing observations. In this type of study, participants are randomly assigned to one of two groups; one group receives the experimental drug while the other receives a placebo (typically a sugar pill). Double-blinded means that neither the participants nor the researchers know who is receiving the drug and who is receiving the placebo until the conclusion of the study. Phase III – Phase III trials are used to prove the efficacy and safety of a drug over the long term and verify Phase II results. These trials are usually double-blinded and placebo-controlled and involve upwards of 1000 patient volunteers. Larger-scale trials are required to see if previously unseen side effects or changes in the drug's efficacy profile appear when testing is done on a sizeable population. Upon completion of this phase, and if the data warrants, a company will file a New Drug Application (NDA) with the FDA. NDA – The NDA filed with the FDA contains all of the data collected by the company throughout the preclinical testing and human trials of the experimental drug. NDAs typically contain more than 120,000 pages of data. It may be filed all once or in a rolling process as sections are completed. |
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