Traditional Drug/Vaccine Development Process

The process of developing a new drug involves five steps. These steps are ordered so that each step builds on information gained during the earlier steps. Each step is described briefly below.

Step 1: Discovery and Development

  • Knowledge of a disease process helps researchers identify potential candidates for development as a drug to treat or prevent a disease
  • Thousands of potential candidates might be studied to identify those that are most promising
  • No human study participants are involved at this stage

Step 2: Preclinical Research

  • These studies do NOT include human study participants
  • May involve the study of cell cultures (In Vitro research) or animal models (In Vivo research)

Step 3: Clinical Research

  • These studies involve human study participants
  • They are called clinical trials. Before starting to do clinical research, the company developing the drug must submit an Investigational Drug Application (IND) to the Food and Drug Administration (FDA)
  • Research cannot begin until the FDA approves the IND
  • INDs are considered proprietary and are not typically made available to the public
  • Clinical research usually involves four distinct phases, with each phase having a different goal
This website will focus on findings from clinical research. Click here to find out about the four phases of clinical research.


Step 4: FDA Review

  • Once the drug developer has evidence that they believe demonstrates that a drug is safe and effective, it can submit a New Drug Application (NDA) to the FDA
  • For vaccines, the vaccine developer submits a Biologics License Application (BLA) instead of a NDA
  • Within the FDA, the Center for Biologics Evaluation and Research (CBER) is responsible for reviewing BLAs and approving new vaccines for use in the US
  • The FDA usually requires data from two large, controlled clinical trials before they will approve a drug for marketing

Step 5: FDA Post-Market Safety Monitoring

You can find more detailed information about the drug development process at, which was the primary source of the information contained on this page.