Getting FDA approval is a multi-year process that costs millions of dollars and, for drugs, succeeds only about 14% of the time from the first human trial to market. The exact path depends on whether you’re developing a drug or a medical device, but both require demonstrating that your product is safe and effective through a structured series of steps. Here’s how the process works for each.
The Five Stages of Drug Approval
Every new drug moves through the same basic sequence: discovery, preclinical testing, clinical trials in humans, FDA review, and post-market monitoring. The entire process from initial discovery to approval typically takes 10 to 15 years, though expedited pathways can shorten the timeline for certain drugs.
In the discovery phase, researchers identify a compound that might treat a disease. This could come from new insights into a disease mechanism, screening thousands of molecules, or modifying an existing drug. Once a promising candidate emerges, it moves into preclinical research: laboratory and animal testing designed to answer basic safety questions. Can the compound cause serious harm? How does the body absorb and process it? What dose range might be effective? The results of this work form the foundation of your first formal FDA submission.
Filing an Investigational New Drug Application
Before you can test a drug in humans, you need to file an Investigational New Drug (IND) application. This is your first major regulatory checkpoint, and the FDA evaluates three things:
- Animal safety data: Your preclinical pharmacology and toxicology results, showing the product is reasonably safe for initial human testing. Any prior human experience with the drug, including use in other countries, goes here too.
- Manufacturing information: Details about how the drug is made, its composition, stability, and quality controls. The FDA needs to know you can produce consistent batches.
- Clinical protocols: Your detailed plan for the human trials you’re proposing, including the qualifications of the investigators who will run them. You must also demonstrate commitments to informed consent and oversight by an institutional review board.
If the FDA doesn’t place a clinical hold within 30 days, you can begin human trials.
Clinical Trials: Phase I Through Phase III
Clinical research unfolds in three phases, each with a different purpose and scale.
Phase I trials typically enroll 20 to 100 healthy volunteers. The goal is safety: finding the right dose range, identifying side effects, and understanding how the body processes the drug. These trials usually last several months.
Phase II expands to several hundred people who actually have the condition the drug is meant to treat. Researchers begin measuring effectiveness while continuing to monitor safety. This is where many drugs fail. The trial design becomes more rigorous, often including a control group that receives a placebo or existing treatment for comparison.
Phase III trials are the largest and most expensive, enrolling hundreds to thousands of patients across multiple sites. These studies generate the definitive evidence of whether the drug works and provide a fuller picture of side effects across diverse populations. Phase III data is what the FDA will scrutinize most closely when deciding whether to approve your drug.
A study of 18 leading pharmaceutical companies found that across more than 2,000 active ingredients and nearly 20,000 clinical trials conducted between 2006 and 2022, the average likelihood of a drug making it from Phase I to FDA approval was 14.3%. Individual company rates ranged from 8% to 23%, depending on therapeutic focus and portfolio strategy.
The New Drug Application and FDA Review
Once you have positive Phase III results, you compile everything into a New Drug Application (NDA). This is a massive submission covering all your preclinical data, clinical trial results, manufacturing details, proposed labeling, and safety information. FDA review teams then examine the full package.
The review follows one of two timelines. Standard review targets a decision within 10 months. Priority review, reserved for drugs that would represent a significant improvement over existing treatments, compresses that to 6 months. Both clocks start when the FDA accepts your application for filing.
The application fees alone are substantial. For fiscal year 2025, the fee for a new drug application requiring clinical data is $4,310,002. Applications that don’t require clinical data cost $2,155,001. These fees, established under the Prescription Drug User Fee program, fund the review process and are separate from the hundreds of millions typically spent on development itself.
Expedited Pathways for Serious Conditions
The FDA offers several programs to speed development and review for drugs targeting serious or life-threatening conditions.
Breakthrough Therapy designation is the most intensive. To qualify, you need preliminary clinical evidence showing your drug may offer a substantial improvement over existing treatments on a meaningful clinical endpoint, such as reducing death, irreversible damage, or serious symptoms. “Substantial improvement” is a judgment call that considers both the size of the treatment effect and the importance of the outcome. If granted, you get more frequent FDA meetings, organizational commitment from senior staff, and rolling review of your application sections as they’re completed rather than waiting until everything is ready.
Fast Track designation applies to drugs that address unmet medical needs for serious conditions. It offers some of the same benefits, including rolling review. Accelerated Approval allows drugs to reach the market based on a surrogate endpoint, a lab measurement or physical sign that’s reasonably likely to predict clinical benefit, with a requirement to confirm the benefit in post-approval studies. Priority Review, as noted above, simply shortens the FDA’s review clock from 10 to 6 months.
These pathways are not mutually exclusive. A single drug can receive multiple designations simultaneously.
How Medical Device Approval Differs
Medical devices follow a fundamentally different system based on risk classification. The FDA recognizes roughly 1,700 types of devices organized into three classes.
Class I devices pose the lowest risk (think bandages, tongue depressors, manual stethoscopes). About 74% of Class I devices are exempt from premarket notification entirely. They still need to follow general regulatory controls like proper labeling and manufacturing standards, but most don’t require a formal submission before going to market.
Class II devices carry moderate risk (powered wheelchairs, pregnancy tests, infusion pumps). These require both general controls and special controls specific to the device type, and most need 510(k) clearance before marketing.
Class III devices are the highest risk category, including things like implantable pacemakers and replacement heart valves. These typically require a Premarket Approval Application (PMA), the most rigorous pathway, which demands clinical trial data proving safety and effectiveness.
The 510(k) Clearance Process
Most new medical devices reach the market through the 510(k) pathway, which requires you to demonstrate that your device is “substantially equivalent” to a device already legally on the market (called a predicate device). Substantial equivalence means your device has the same intended use as the predicate and either shares its technological characteristics or, if it differs technologically, doesn’t raise new safety or effectiveness questions.
To prove this, you submit performance data comparing your device to the predicate. This can include engineering bench testing, biocompatibility evaluations, software validation, sterility testing, electromagnetic compatibility data, and sometimes clinical data. The FDA reviews your comparison and either agrees your device is substantially equivalent (clearing it for market) or determines it’s not, which typically means you need the more demanding PMA pathway.
The 510(k) process is significantly faster and cheaper than a PMA. Reviews typically take three to six months, compared to a year or more for a PMA. But it’s worth noting that 510(k) clearance means the FDA found the device comparable to something already on the market. It doesn’t mean the device went through independent clinical trials proving it works.
After Approval: Post-Market Monitoring
FDA approval isn’t the finish line. For both drugs and devices, the FDA continues monitoring safety after products reach the public. Drug manufacturers must report adverse events, and the FDA can require additional studies, label changes, or even market withdrawal if new safety concerns emerge. For devices, the FDA maintains a database of reported problems and can issue recalls or safety alerts. Some approvals, particularly those granted under accelerated pathways, come with specific requirements for post-market studies to confirm that the early evidence of benefit holds up in broader real-world use.