FDA’s Abbreviated New Drug Application Process Explained: How Generic Drugs Get Approved

When you pick up a prescription at the pharmacy and see a much cheaper version of a brand-name drug, you’re holding a product approved through the Abbreviated New Drug Application (ANDA) process. This isn’t a shortcut-it’s a carefully designed system that lets safe, effective generic drugs reach patients without repeating every single clinical trial ever done for the original. The ANDA process is how over 90% of prescriptions in the U.S. end up being generics, saving the healthcare system nearly $400 billion every year.

What Exactly Is an ANDA?

The Abbreviated New Drug Application is a regulatory pathway created by the Hatch-Waxman Act of 1984. It lets generic drugmakers apply for FDA approval without submitting full clinical trial data. Instead, they prove their drug is the same as an already approved brand-name drug, called the Reference Listed Drug (RLD). The FDA already confirmed the safety and effectiveness of that original drug. So the generic applicant doesn’t need to start from scratch.

The word "abbreviated" doesn’t mean "less rigorous." It means the application skips redundant studies. The generic drug must match the RLD in every key way: same active ingredient, same strength, same dosage form (pill, injection, cream), same way it’s taken (oral, topical, etc.), and same intended use. Even the labeling has to be nearly identical, with only minor exceptions allowed.

One big difference from brand-name drugs? Generics don’t need to prove they work in large patient groups. Instead, they prove they’re bioequivalent. That means the body absorbs the generic drug at the same rate and to the same extent as the brand. If a patient switches from the brand to the generic, their body reacts the same way. No surprises.

How the ANDA Process Works Step by Step

The ANDA process isn’t fast, but it’s predictable-if you know what to expect. Here’s how it breaks down:

1. Submission: The company files the ANDA electronically through the FDA’s Electronic Submission Gateway. They include FDA Form 356h (the application) and Form 3674 (financial disclosures). The filing division checks for completeness within 60 days. If anything’s missing, they’ll send a refusal-to-file letter.
2. Discipline Review: Once accepted, the application goes to teams of scientists: chemists check the drug’s composition, manufacturing experts review the facility processes, microbiologists look at sterility controls, and labeling specialists compare the text to the RLD. The bioequivalence team analyzes the study data-this is where most applications stumble.
3. Information Requests: If reviewers find issues, they send an Information Request (IR) or Discipline Review Letter (DRL). These aren’t rejections-they’re requests for more data. Common problems? Bioequivalence studies that don’t meet FDA standards, manufacturing flaws, or labeling mismatches. One company reported getting 17 IRs on their first ANDA, stretching the review by over a year.
4. Final Decision: If all issues are resolved, the FDA gives either a Final Approval or a Tentative Approval. Final Approval means the drug can be sold right away. Tentative Approval means the science checks out, but the FDA can’t approve it yet because of patents, exclusivity periods, or court orders. Once those legal blocks expire, Tentative Approval turns into Final Approval automatically.

Under the Generic Drug User Fee Amendments (GDUFA III), the FDA aims to complete its first review of an original ANDA within 10 months. But the whole process-from filing to approval-usually takes about 30 months. That’s still far faster than the 10-15 years it takes to bring a brand-name drug to market.

Why ANDA Is So Much Cheaper Than a New Drug Application

Developing a brand-name drug (via a New Drug Application or NDA) costs an average of $2.3 billion. That includes decades of research, dozens of clinical trials, and massive regulatory overhead. The ANDA process? It costs between $1 million and $5 million per application. That’s why generic drugs cost, on average, just 15% of the brand-name price once they hit the market.

Here’s the math: A brand-name drug might cost $500 a month. The generic version? $75. Multiply that by millions of prescriptions, and you get $373 billion in annual savings for the U.S. healthcare system. That’s not just corporate profit-it’s money back in patients’ pockets, lower insurance premiums, and less strain on Medicare and Medicaid.

But cost savings don’t mean lower quality. The FDA holds generic manufacturers to the same standards as brand-name makers. Every facility is inspected. Every batch is tested. The active ingredient in a generic pill has to be identical to the brand. The fillers and coatings might differ, but they’re still approved, safe, and tested for stability.

What Makes Some Generics Harder to Approve?

Not all generics are created equal. Simple pills? Easy. Complex products? Much harder.

Topical creams, inhalers, injectables, and transdermal patches are called "complex generics." They don’t just need to match the active ingredient-they need to match how the drug behaves in the body, which depends on the delivery system. For example, a generic asthma inhaler must deliver the same amount of medicine to the lungs as the brand. That’s not easy to prove. In fact, 35% of Complete Response Letters from the FDA cite problems with bioequivalence studies for complex generics.

One manufacturer spent $1.2 million and ran three rounds of bioequivalence testing just to get approval for a generic topical cream. They had to change the formula twice and redo the study each time. That’s why many companies now use Quality by Design (QbD) principles-building in quality from the start instead of testing it at the end.

And then there’s the patent maze. Sometimes, a brand-name company extends its monopoly by filing dozens of minor patents-on packaging, dosing schedules, or even manufacturing methods. These "patent thickets" delay generic entry, even when the core patent has expired. The FDA can’t approve a generic until those legal barriers are cleared, which is why Tentative Approval exists.

Who’s Winning in the Generic Drug Market?

The U.S. generic market was worth $127.6 billion in 2022 and is expected to hit nearly $190 billion by 2027. The biggest players? Teva Pharmaceuticals leads with 22% of the market, followed by Viatris (formerly Mylan) at 15%, and Sandoz at 12%. But 75% of ANDAs come from companies that already have five or more approved generics. Experience matters.

Companies that file multiple ANDAs learn the system. Teva’s regulatory team says after their tenth approval, they hit GDUFA timelines 92% of the time. They’ve built templates, trained staff, and streamlined communication with the FDA. Newer companies? They often get hit with unexpected Information Requests. Over 78% of applicants report getting at least one IR. That’s normal. It’s part of the learning curve.

What’s Next for the ANDA Process?

The FDA isn’t sitting still. The Complex Generic Drug Products Initiative, launched in 2018, is pushing for better tools to evaluate tricky products. GDUFA III, effective in 2022, set new performance goals: 90% of original ANDAs reviewed within 10 months. And the FDA is now using AI-assisted tools in 78% of chemistry reviews to speed up analysis.

Real-world evidence is also becoming more accepted. Instead of only relying on lab studies, the FDA is starting to consider data from electronic health records and insurance claims to support bioequivalence claims for complex generics.

Internationally, the FDA is working with the International Council for Harmonisation (ICH) to align standards with Europe, Japan, and Canada. That means fewer duplicate studies and faster global access to generics.

But challenges remain. Patent protections, REMS programs (Risk Evaluation and Mitigation Strategies), and manufacturing delays still block access. And while the system works well for most drugs, patients waiting for a generic version of a life-saving injectable or inhaler often face long delays.

Bottom Line: The ANDA Process Works

The ANDA process isn’t perfect, but it’s one of the most successful public health policies in modern medicine. It balances innovation with access. It rewards companies that invest in science without requiring them to repeat decades of prior research. It saves billions and gives patients affordable options.

If you’ve ever chosen a generic drug because it was cheaper and still worked just as well-you’ve benefited from this system. The FDA didn’t cut corners. They built a smarter path. And for millions of people, that path means keeping their prescriptions filled, their bills lower, and their health on track.

What to Do If You’re Considering a Generic Drug

If you’re switching from a brand to a generic, talk to your pharmacist or doctor. Ask if the generic is approved under an ANDA. Check the FDA’s online database of approved drugs to confirm it’s listed. If you notice a change in how the drug works after switching, report it. It’s rare, but not impossible. Most people experience no difference at all.

The ANDA process isn’t just about saving money. It’s about making sure everyone can get the medicine they need-without paying more than they have to. And that’s a system worth understanding.