Becoming a drug

From initial studies to FDA approval, the process takes about 15 years

Here’s what it takes to get the stamp of approval needed to sell a drug in the United States — a green light from the U.S. Food and Drug Administration.

Test it in the tube
Researchers add the potential drugs one at a time to small batches of enzymes, cell cultures or cellular substances. Compounds that set off interesting reactions get further study, including testing for toxicity.

Test it in animals
Before testing the compound in humans, the FDA requires researchers to assess its effects on animals. And since a drug might affect one species differently from another, they usually test it on two or more species — a rodent, such as mice or rats, and a non-rodent, typically a larger animal such as pigs. Researchers measure how much of the compound the animal’s blood absorbs, how toxic it is and how the body breaks it down chemically and eliminates it. In some cases, they also run tests extending for several years to learn whether long-term use causes cancer or birth defects.

Test it in humans
If the potential drug proves safe in animal trials, the FDA gives the go-ahead for clinical trials — tests in humans. These tests advance through three phases.

Phase-1 clinical studies: Safety
These relatively small-scale studies, usually involving 20 to 80 subjects, are designed to reveal the drug’s metabolic and pharmacologic actions in humans, the side effects and, if possible, its effectiveness.

Phase-2 clinical studies: Efficacy
This phase of testing provides preliminary data on the effectiveness of the drug in patients with the disease or condition and offers additional evidence of the drug’s short-term side effects and risks. These studies usually involve several hundred patients.

Phase-3 clinical studies: Safety in numbers
If phase-2 studies appear promising, researchers move on to larger phase-3 trials, which usually include several hundred to several thousand people. These provide additional information about effectiveness and safety.

Decision time
The drug company sends the results of the studies to an FDA committee in the Office of New Drugs that weighs the compound’s health benefits against health risks. If the benefits are strong enough, the FDA approves the compound for sale. For drugs on the high-priority fast-track this takes about six months. For others, it takes about 15 months.


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