Why Some Drug Patents Last Longer Than 20 Years
Most patents expire 20 years after the first filing. But if you look at the expiration date on a blockbuster drug like Humira or Keytruda, you’ll often see a date that’s 25, 26, even 27 years after the original application. That’s not a mistake. It’s Patent Term Restoration (PTE) - a legal loophole designed to make up for time lost waiting for the FDA to approve a new drug.
Here’s the problem: Drug companies file patents early - sometimes before they even start human trials. That’s smart. It locks in protection before competitors can copy the idea. But then comes the real bottleneck: the FDA approval process. It takes, on average, 10 to 15 years just to get a new drug from lab to pharmacy shelf. By the time the drug hits the market, half the patent life is already gone. That’s not fair to companies that spent billions developing it. So Congress created PTE in 1984 under the Hatch-Waxman Act to fix that imbalance.
How PTE Actually Works
PTE isn’t automatic. It’s a precise calculation. The formula looks complicated, but here’s the simple version:
- Start with the total time the drug spent under FDA review (called the Regulatory Review Period).
- Subtract any time the company was slow to respond to FDA requests (that’s the "due diligence" clock).
- Then subtract half the time between filing the patent and submitting the drug for FDA review.
The result? The number of extra years the patent gets. But there are hard limits: you can’t get more than five years added, and the total patent life - original plus extension - can’t go beyond 14 years after the FDA approves the product.
For example: If a drug took 7 years to get FDA approval, and the company was fully responsive the whole time, they might get 4.5 years of extension. That means if the patent would’ve expired in 2030, it now expires in 2034. That extra time means the company can keep charging high prices without generics knocking on the door.
Who Gets PTE - and Who Doesn’t
PTE isn’t for every patent. It only applies to specific products:
- Human drugs (prescription and over-the-counter)
- Medical devices
- Food additives
- Color additives
- Animal drugs (added in 1988)
It doesn’t apply to software, gadgets, or industrial chemicals. And even within drugs, not every patent qualifies. Only patents that claim the active ingredient, the product itself, or the method of using it are eligible. A patent on the pill’s color? Not eligible. A patent on a new delivery system? Maybe - if it’s tied directly to the FDA-approved product.
Also, you can only get one PTE per product. If a company has five patents on the same drug, they pick one to extend. The others? They expire on time. That’s why you’ll often see companies file dozens of "secondary" patents - on formulations, dosages, or packaging - just to keep competitors out even after the main patent expires.
The Hidden Costs and Controversies
PTE was meant to balance innovation and access. But in practice, it’s become a tool for extending monopolies far beyond what Congress intended.
Here’s the data: Between 2010 and 2020, over 1,200 PTEs were granted in the U.S. And according to a 2022 Yale study, 91% of drugs that got PTE kept their market dominance long after the extension ended - not because of new patents, but because of patent thickets. That’s when companies file dozens of minor patents around the same drug, making it legally risky for generics to enter.
And it’s expensive. The Congressional Budget Office estimates PTE adds $4.2 billion a year to U.S. drug spending. When a drug gets a 5-year extension, it means patients and insurers pay brand-name prices for half a decade longer. The FTC found that during the extension period, branded drugs hold onto 92% of the market. Once generics arrive, that drops to 37%.
Even worse, nearly 78% of PTE applications in recent years aren’t for the original compound patent - they’re for secondary patents on delivery methods, salts, or metabolites. Critics say this turns PTE into a loophole for evergreening, not compensation.
The Application Process: A Minefield of Paperwork
Getting PTE isn’t just filling out a form. It’s a legal marathon.
First, the company has just 60 days after FDA approval to file. Miss that window? You lose the extension forever. No exceptions.
Then comes the documentation. The FDA requires day-by-day proof that the company was moving as fast as possible. That means:
- Every email sent to the FDA
- Every meeting agenda and minutes
- Every submission date
- Every request for information and how quickly it was answered
One pharmaceutical patent attorney told a Reddit community in 2024: "The most common mistake? Underestimating the documentation trail. We’ve seen applications denied because they couldn’t prove someone was working on the file during a weekend holiday."
The USPTO denies about 12.7% of applications - mostly for lack of due diligence. And the average processing time? Over 217 days. Companies often delay filing until the last possible moment, hoping the FDA will finish its review before the patent expires. Some even use a temporary "interim extension" to keep protection alive while waiting for final approval.
What’s Changing in 2025 and Beyond
The rules are tightening. In January 2024, the FDA released new guidance on "due diligence," making it clearer what counts as progress and what doesn’t. Then in 2024, a Federal Circuit court case (Eli Lilly v. USPTO) ruled that companies can’t claim credit for time spent waiting for internal approvals - only time spent waiting for the FDA.
That could shrink average extensions by 8 to 12 months. It’s a big deal. For a drug making $2 billion a year, losing even six months of exclusivity means $1 billion in lost revenue.
At the same time, the FDA is working on a digital submission system for PTE applications - expected in 2026. Right now, everything’s paper-based. That’s slow. That’s error-prone. That’s why so many applications get rejected.
And there’s political pressure. The proposed Preserve Access to Affordable Generics and Biosimilars Act would block certain PTE strategies, especially those tied to secondary patents. The Government Accountability Office is set to release a full review of PTE’s impact on drug prices in December 2025. If the findings are negative, Congress could change the law.
Why This Matters to You
If you take prescription drugs, PTE affects your out-of-pocket costs. If you work in pharma, it’s a make-or-break tool for ROI. If you’re a generic manufacturer, it’s the wall you have to climb over.
Right now, PTE is a system that works - but it’s stretched thin. It was designed to reward innovation, not to create decades-long monopolies. The original intent was fair: give companies back the time they lost waiting for regulators. But today, it’s often used to delay competition, not to encourage development.
As biologics and personalized medicines become more common, PTE will be used even more. In 2023, 34% of PTE applications were for biologics - up from 19% in 2018. That’s a trend that won’t reverse.
The real question isn’t whether PTE should exist. It’s whether it should be reined in. Because when a patent lasts 27 years on a drug that costs $100,000 a year, the cost isn’t just financial - it’s ethical.
Frequently Asked Questions
What is the difference between PTE and PTA?
PTE (Patent Term Extension) makes up for delays caused by the FDA during drug approval. PTA (Patent Term Adjustment) makes up for delays caused by the USPTO during patent examination. They’re two different systems. PTE is about regulatory review. PTA is about patent office backlog. You can get both, but they’re calculated separately.
Can a patent get more than one PTE?
No. Only one patent per product can receive a PTE. If a company has multiple patents covering the same drug - like one for the molecule, one for the pill shape, one for the delivery method - they have to pick just one to extend. The others expire on schedule. That’s why companies file so many patents: to have options.
How long does the FDA take to approve a PTE application?
The FDA doesn’t approve the extension - it just gives the USPTO the data on how long the drug was under review. The USPTO then calculates the extension. The whole process, from filing to final decision, takes about 217 days on average. But if the application is incomplete or lacks proper documentation, it can take much longer - or be denied.
What happens if I miss the 60-day filing deadline?
You lose the right to PTE forever. There are no extensions, no exceptions, no appeals. The 60-day clock starts the day the FDA gives final approval. Many companies miss this deadline because they’re focused on launching the drug, not the paperwork. One mistake, and you’re giving away years of exclusivity.
Are PTEs only for big pharmaceutical companies?
No. The law applies to anyone - small biotech startups, academic spin-offs, even individual inventors. But the process is so complex and expensive that only companies with legal and regulatory teams can handle it well. The FDA offers free guidance through their SBIA portal, but the application still requires patent attorneys and regulatory experts. Most small companies hire outside firms, which can cost $50,000 to $150,000 per application.
Can a generic drug company challenge a PTE?
Not directly. But when a generic company files an Abbreviated New Drug Application (ANDA), they can challenge the validity of the patent that was extended. If the court finds the patent was improperly granted or doesn’t cover the actual product, the PTE can be invalidated. That’s why PTE applications are often tied to litigation - the patent and the extension are both on the line.
Does PTE apply to biosimilars?
Yes. Since 2016, the 21st Century Cures Act expanded PTE eligibility to include certain regenerative medicine products and biologics. In fact, biologics now make up 34% of all PTE applications - up from 19% in 2018. Biologics are complex, expensive to develop, and take even longer to approve than traditional drugs. PTE is even more critical for them.
Next Steps
If you’re a drug developer, start tracking your FDA timeline the day you file your patent. Don’t wait until approval. Keep daily logs of every interaction with regulators. Assign one person to manage the PTE application - it’s too important to be an afterthought.
If you’re a patient or insurer, understand that when a drug gets a PTE, your costs will stay high for longer. Ask your pharmacist: "Is this drug still under patent extension?" That information is public in the FDA’s Orange Book.
If you’re a policy maker or advocate, watch the GAO’s December 2025 report. It could be the turning point for PTE reform. The system was built to help innovation. But right now, it’s helping profits more than patients.
Pharmacology
Paul Ong
January 1, 2026 AT 06:22they patent the idea before the drug even exists then sit on it for a decade while the FDA does the work
Richard Thomas
January 2, 2026 AT 03:26gerard najera
January 3, 2026 AT 23:04Austin Mac-Anabraba
January 5, 2026 AT 13:16Phoebe McKenzie
January 5, 2026 AT 23:23Ann Romine
January 6, 2026 AT 05:47Layla Anna
January 7, 2026 AT 08:44Todd Nickel
January 8, 2026 AT 19:32