FDA Approval Process Explained: A Founder's Guide

For a first-time founder, the FDA can look like a black box at the end of the journey. It is not. The approval framework is public, logical, and best understood as a series of evidence gates. This guide walks through the path from laboratory to market, with primary sources, so you can plan around it rather than react to it. It is general information, not legal or regulatory advice.

Preclinical work and the IND

Before a candidate can be given to people, a sponsor runs laboratory and animal studies to characterize safety and biological activity, then submits an Investigational New Drug application, or IND. The IND is the formal request to begin human testing, and clinical research cannot start until it is in effect (U.S. FDA, Step 3). Founders often underestimate how much preclinical and manufacturing information the IND requires.

The three clinical phases

Human testing proceeds from small, early studies to large, late ones (U.S. FDA, Step 3).

• Phase 1 tests a small number of participants, focused on safety, dosing, and how the body handles the drug.
• Phase 2 enrolls more participants to look for early evidence of effect and to refine dosing and safety.
• Phase 3 is the large, often controlled study designed to confirm benefit and characterize safety in a population that resembles real-world use.

This is where most programs end. As noted in a companion piece on why biotech startups fail, the probability of moving from first-in-human to approval is in the low double digits at best.

NDA, BLA, and the 351(a) pathway for biologics

How a finished application is filed depends on what the product is. A conventional small-molecule drug is submitted as a New Drug Application. A biologic, meaning a product derived from living sources such as proteins, cells, or tissues, is submitted as a Biologics License Application under Section 351(a) of the Public Health Service Act. The 351(a) pathway is the full license route for a biologic and carries its own manufacturing and characterization expectations. Choosing and understanding the correct pathway early shapes the entire development plan.

FDA review

Once an application is filed, an FDA review team examines all of the submitted data and decides whether to approve. For a complete application, the review team generally has six to ten months to reach a decision, with specialists reviewing their respective sections, from clinical data to manufacturing (U.S. FDA, Step 4). Approval is not the end of oversight. Post-market requirements and ongoing safety monitoring continue after launch.

Expedited pathways worth knowing

The FDA offers several programs to speed development of therapies for serious conditions, including Fast Track, Breakthrough Therapy, Accelerated Approval, and, for regenerative medicine, the Regenerative Medicine Advanced Therapy, or RMAT, designation created under the 21st Century Cures Act. RMAT brings the benefits of Breakthrough designation, including early and frequent FDA interaction and eligibility for priority review and accelerated approval based on appropriate endpoints (U.S. FDA, RMAT designation). These programs do not lower the evidence bar, they change the cadence and the dialogue.

Talk to the FDA early, not late

One of the most valuable and least used levers is structured dialogue with the agency. A pre-IND meeting lets a sponsor confirm that its preclinical package and trial design will support a human study before committing the budget. Later milestone meetings, such as an end-of-Phase-2 meeting, align the sponsor and the agency on what the pivotal trial must show. The expedited programs described above exist in part to enable this kind of early, frequent interaction. Founders who treat the FDA as a partner to consult, rather than a gate to clear at the end, avoid the expensive mistake of designing a trial the agency was never going to accept.

What an application actually contains

A finished NDA or BLA is not a summary, it is the full evidentiary record. It pulls together the clinical trial results, the complete safety database, the detailed manufacturing and controls package, proposed labeling, and plans for managing risk after approval. The manufacturing section alone can be enormous, because the agency must be satisfied that the product can be made consistently at commercial scale. This is one reason manufacturing belongs in the plan from the beginning, a point developed in the companion piece on why manufacturing is the real moat. Approval is also not the finish line. Post-market commitments, safety surveillance, and inspections continue for the life of the product.

What founders underestimate

Three things, consistently. The depth of manufacturing information required, even early, which is the subject of the companion piece on manufacturing as a moat. The importance of choosing the approval endpoint before designing the pivotal trial. And the value of engaging the agency early, which the expedited programs are designed to enable. Treating the regulatory pathway as a strategy rather than a submission is the difference, and it is where experienced advisory earns its keep.