The drug approval process is rigorous. Only a small portion of the drugs submitted to the U.S. Food and Drug Administration (FDA) are approved and it takes an estimated 8.5 years on average for a drug to go from early laboratory discovery to approval for human use.

Throughout this process, a Sponsor and the organizations responsible for developing the new drug, must coordinate with the Center for Drug Evaluation and Research (CDER) or the Center for Biologics Evaluation and Research (CBER) on the clinical trial design, analysis of results, and permission to conduct and escalate human testing. For cancer drugs, sponsors engage with CDER’s Oncology Center of Excellence (OCE). Sponsors submitting new drugs are also required to pay user fees in order to support FDA in operating efficiently. FDA identifies twelve steps in the complete development and review collaboration.

1. Early Development and Preclinical Testing: Drug development begins with laboratory research into chemical interactions, often building on preliminary work from academic groups, government institutions such as the National Institutes of Health (NIH), and prior development studies. Once a sponsor has developed a chemical that they believe could be used as a treatment for a disease, they must conduct animal testing in order to demonstrate that the chemical is safe. The FDA will not allow human testing of substances that have not been shown to be reasonably safe in animals.
2. Investigational New Drug Application: Before a sponsor can begin clinical trials, they must submit an application to the FDA describing their pre-clinical trials, the drug’s composition and manufacturing, and the plan for human clinical testing. This is called an Investigational New Drug Application, or IND.
3. Phase 1 Clinical Testing: If the FDA approves a Sponsor’s IND, the Sponsor may begin a Phase 1 clinical trial. This trial usually involves a small number of patients–between 20 and 80, depending on the nature of the drug and the condition it is intended to treat–and is focused primarily on safety, potential side effects, and how the drug is metabolized and excreted.
4. Phase 2 Clinical Testing: If Phase 1 testing finds that the drug is reasonably safe, the sponsor can move on to Phase 2 clinical trials. These are intended to demonstrate a drug’s efficacy often through comparison with a control or standard of care.
5. Phase 3 Clinical Testing: If Phase 2 testing demonstrates that a drug is effective against a condition for a certain population, sponsors and FDA officials meet to discuss how a Phase 3 trial should be conducted in order to demonstrate sufficient safety and effectiveness for approval. Phase 3 clinical trials are the largest trials and often require a comparison to a control arm. In addition to safety and efficacy, these trials gather information on appropriate dosing, interactions with other chemicals, and the drug’s impact on different populations.
6. Review Meeting: During the pre-NDA period, just before a new drug application (NDA) is submitted. A common time for the FDA and drug sponsors to meet.
7. New Drug Application: Having completed Phase 3 trials, a sponsor submits a New Drug Application, or NDA (a Biologics License Application, or BLA, in the case of biological medical products), formally requesting FDA approval for their drug. This application includes all testing data as well as chemical and manufacturing information.
8. Application Filing: Once an NDA or BLA has been submitted, the FDA has 60 days to decide whether or not to file it, opening it for review. The FDA may refuse to file an application if it is incomplete.
9. Application Review: Assuming the NDA or BLA has been filed, it is now reviewed by FDA officials to determine the drug’s safety and efficacy. The FDA reviews and act upon NDAs within 10 months (or six months if the drug has received the priority review designation.) In some cases involving drugs intended to treat cancer, the FDA will convene a meeting of the Oncologic Drugs Advisory Committee, or ODAC, to make recommendations.
10. Drug Labeling: The FDA examines a sponsor’s proposed labeling to ensure that safe, accurate information about the drug’s appropriate use is communicated to patients and healthcare providers.
11. Facility Inspection: The FDA inspects the facilities where a drug will be manufactured in order to ensure that the drug can be safely produced.
12. Approval: Depending on their findings following NDA or BLA submission, the FDA will either approve the application or issue a complete response letter outlining their decision.

Once a drug has been approved, sponsors are often responsible for additional post-market research to confirm their drug’s safety, effectiveness, and optimal use.

At every step, ineffective or unsafe drugs are removed from FDA consideration. It is estimated that only 20% of drugs to receive Phase 1 testing end up reaching the market.