The New Drug Application (NDA) is the vehicle through which drug sponsors formally propose that the FDA approve a new pharmaceutical for sale and marketing in the U.S. In other words, when the sponsor of a new drug believes that enough evidence on the drug’s safety and effectiveness has been obtained to meet the FDA’s requirements for marketing approval, the sponsor submits to the FDA a New Drug Application (NDA). Once a NDA is submitted, the FDA has 60 days to decide whether it intends to file it so that it can be reviewed. The FDA can refuse to file an application that is incomplete. If the application is filed, the review team has 6 to 10 months to make a decision on whether to approve the drug. When a sponsor submits a generic drug for marketing approval, they submit an Abbreviated New Drug Application (ANDA) instead of a full NDA. In an ANDA, the applicant is claiming that their drug is a duplicate of an already-approved drug.
It usually takes 8 to 10 months to review an Abbreviated New Drug Application from the date of submission. Once approved, an applicant may manufacture and market the generic drug product to provide a safe, effective, lower cost alternative to the brand-name drug it references.
References : Nuventra, NRS Advisors, USFDA