Bringing a new medication to the public is a lengthy process governed by strict regulations to ensure it is both safe and effective. The journey from an initial idea to an approved prescription takes an average of 10 to 15 years and involves discovery, laboratory testing, human trials, and regulatory review. The high cost is influenced by the high rate of failure, as most potential drugs never reach the market.
Discovery and Preclinical Research
Drug development begins with researchers identifying a “target,” such as a protein or gene involved in a disease. Scientists then use high-throughput screening to test thousands to millions of chemical compounds to see if they can interact with this target. Promising molecules, known as “hits,” are then chemically optimized to improve their specificity and how well they bind to the target.
A promising compound then enters preclinical research, which takes several months to a few years. This stage involves laboratory testing to gather data on the drug’s safety and biological activity before human administration. Studies are conducted in vitro (in a lab environment) and in vivo (in animal models). Researchers analyze the compound’s pharmacokinetics—how it is absorbed, distributed, metabolized, and excreted—and its pharmacodynamics, or what the drug does to the body. The goal is to determine a safe dosage for human trials and identify potential harm; only one in 1,000 compounds from this stage proceeds to human testing.
The Clinical Trial Process
After a compound passes preclinical research, it moves into clinical trials, the longest part of drug development. This process has three distinct phases, each designed to answer different questions about the new treatment. The goal is to build a comprehensive profile of the drug’s safety and effectiveness in humans before it can be considered for wider use.
Phase 1 is focused on safety. These trials involve 20 to 100 healthy volunteers and take several months to a year. The goals are to determine the most frequent side effects and establish a safe dosage range. Researchers also monitor the drug’s pharmacokinetics. About 70 percent of experimental drugs pass this phase.
With safety data from Phase 1, the drug advances to Phase 2, which concentrates on effectiveness. Lasting from several months to two years, these studies enroll several hundred patients who have the condition the drug is intended to treat. The primary goal is to determine if the drug works on the intended disease while continuing to gather data on short-term side effects and risks.
Phase 3 trials are the final stage of testing before regulatory submission. These large-scale studies involve several hundred to several thousand patients and may last for several years. The objective is to confirm the drug’s effectiveness in a diverse population, monitor side effects, and compare it to existing treatments or a placebo. To prevent bias, these trials are often “double-blinded,” meaning neither the participant nor the researcher knows who is receiving the experimental drug. The data collected is used to create the drug’s labeling if approved.
Regulatory Review and Approval
After completing clinical trials, the sponsor requests approval by submitting a New Drug Application (NDA) to a regulatory agency like the U.S. Food and Drug Administration (FDA). This application is a comprehensive compilation of all data from the discovery, preclinical, and clinical stages. The NDA details the drug’s chemistry, manufacturing, and the full results of human trials, demonstrating both safety and efficacy.
Once the NDA is submitted, the FDA has 60 days to decide if the application is complete enough for a full review. If filed, the standard review timeline is ten months. A Priority Review designation for drugs that offer major advances in treatment can shorten this to six months.
During the review, a team of physicians, statisticians, and other scientists evaluates the data to ensure the drug’s benefits outweigh its known risks. The agency also inspects manufacturing facilities to verify quality. The review may include recommendations from an advisory committee of external experts. Based on this evaluation, the agency will either issue an approval letter or a Complete Response Letter detailing deficiencies that must be addressed.
Post-Market Monitoring
A drug’s evaluation continues after it receives regulatory approval. This period involves post-market monitoring, often called Phase 4 clinical trials. These studies are conducted after the drug is on the market to gather additional information on its safety, effectiveness, and optimal use in a real-world setting. This stage helps in understanding the drug’s performance across diverse populations over a long period.
Phase 4 surveillance identifies rare or long-term side effects not detected during earlier clinical trials. As thousands of patients use the medication, some adverse events may only become apparent after prolonged use or in specific demographic groups. This ongoing data collection helps ensure the drug’s safety profile remains favorable.
Data from post-market studies can lead to updates in a drug’s labeling, such as new warnings, or inform its use with other treatments. If significant safety concerns arise, a drug may be withdrawn from the market. This final monitoring stage ensures a drug’s long-term benefits continue to justify its risks for patients.