Is Patent Evergreening Smart Strategy or System Abuse?
When an early patent on a successful product nears expiration and newer patents keep it protected, critics call it “evergreening.” But is it clever innovation management or a way to game the system? In this episode of Patenting for Inventors, Adam Diament, registered patent attorney and partner at Nolan Heimann, takes on one of the most debated terms in patent law.
Adam explains why a single product is rarely covered by just one patent, and why patents on genuine improvements, such as a better formulation, a new delivery method, or a more efficient design, can be entirely lawful. He walks through where the controversy really lies: minor or obvious changes, continuation practice, double patenting and terminal disclaimers, and the role prosecution history plays when patents are challenged years later. Using examples from the pharmaceutical industry to everyday consumer products, he shows why the label itself never decides whether a patent is valid.
For inventors, startups, and growing companies, this episode offers a practical framework for building a patent portfolio that reflects real technical progress. Learn how to document improvements, why each filing should stand on its own invention, and how to grow protection that holds up when it matters most.
Patenting for Inventors Ep. 182:
Podcast Transcript:
Hello, and welcome to the Patenting for Inventors podcast. I’m your host, Adam Diament, a registered patent attorney and partner at Nolan Heimann in Los Angeles, California.
Today we are talking about patent “evergreening.”
You may have heard that word in news stories about pharmaceutical companies, large technology companies, or patents that seem to keep a product protected for years.
The word can sound suspicious, almost like a company is cheating the system. But what does it actually mean?
Let’s start with a simple example.
Imagine that a company develops a new medication. It obtains a patent on the original drug compound. That patent will eventually expire.
Before it expires, the company develops a new version of the medication. Maybe the new version lasts longer in the body, causes fewer side effects, is easier to store, or can be taken less frequently.
The company files a new patent application on that improvement.
People who criticize the company may call that “evergreening.” They may say the company is trying to keep competitors, including generic-drug companies, out of the market.
But from the company’s perspective, it has created a new invention and is asking for a new patent.
That is the basic debate.
“Evergreening” is not a term you will find in the U.S. patent statute. It is a nickname used by commentators, competitors, government agencies, and courts to describe certain patent strategies.
Usually, the term refers to building a series of patents around a product so that newer patents remain in force after an earlier, foundational patent expires.
The “evergreen” image comes from a tree that keeps its leaves year after year.
Now, a patent does not last forever. For a U.S. utility patent, the basic term is generally twenty years from the earliest effective nonprovisional filing date. There can be adjustments or extensions in some situations, and maintenance fees must be paid to keep the patent in force.
A provisional application does not start the twenty-year term. The term generally relates to the later nonprovisional application that claims its benefit.
Here is the part that makes things complicated: a product is rarely protected by just one patent.
A single product might involve separate inventions relating to:
the basic product;
a manufacturing process;
a chemical formulation;
a delivery system;
a software feature;
a method of using the product; or
an improvement made several years later.
Each of those inventions might be described in a separate patent application.
So when someone says a company is “evergreening,” they may mean that an earlier patent is expiring while newer patents are still protecting improvements or other aspects of the same commercial product.
That is not automatically illegal.
The patent system does not say that a product is entitled to only one patent. It says that a new and non-obvious invention may qualify for patent protection if the other legal requirements are satisfied.
For example, suppose you invent a coffee maker.
Your first patent might cover a new heating system. Later, you develop a new water-filtration system that makes the coffee taste better. Later still, you develop a control system that uses less electricity.
Those later inventions may be patentable if they are genuinely new and not obvious, even though they are improvements to your original coffee maker.
That is not necessarily abuse. It may simply be continued innovation.
The controversy begins when people believe the later inventions are only minor or obvious changes designed mainly to delay competition.
For example, critics might question a patent covering:
a very minor change in dosage;
a routine change in packaging;
a small alteration that provides no meaningful technical benefit; or
a feature that competitors could easily have developed using ordinary skill.
That is primarily a patentability question.
To receive a patent, an invention must be new and non-obvious. It also must be adequately described and enabled, meaning the application must explain the invention well enough for a skilled person to make and use it.
If a claimed improvement is obvious, it should not receive a valid patent simply because it is attached to a successful product.
The word “evergreening” does not itself decide whether a patent is valid. The actual claims and the evidence matter.
This issue is especially visible in the pharmaceutical industry.
Drug research is expensive and can take many years. A company may spend enormous amounts of money developing and testing a drug before it can sell it.
A genuine improvement can be valuable. For example:
a new formulation may make the drug last longer on the shelf;
a new delivery method may reduce side effects;
a different dosing schedule may make treatment easier;
a new combination may improve how the drug works; or
a more stable formulation may eliminate the need for refrigeration.
Those may be real technical improvements.
At the same time, critics may argue that some later patents are designed mainly to delay generic competition. Sometimes that criticism may have merit. Sometimes the later patent protects a meaningful improvement. Often, the answer depends on the particular facts.
The legal question is not simply, “Is this evergreening?”
The legal questions are:
What exactly does the patent claim?
Is that subject matter new?
Is it non-obvious?
Is it adequately described?
Is it enabled?
Was the application prosecuted honestly?
Is the patent being used in a way that violates another law?
The label may be useful for public debate, but it does not replace those legal questions.
Evergreening can also involve continuation applications.
A continuation is a new application that claims priority to an earlier application and uses the earlier application’s disclosure. It may contain a different set of claims directed to another aspect of the invention.
For example, the first application might claim a device. A continuation might claim a method of operating the device. Another continuation might claim a particular component.
Continuation practice is legitimate, but it does not create permission to add new technical material that was not supported by the earlier application. New matter generally requires a new filing date.
There can also be limits involving double patenting. In simple terms, the law does not allow an applicant to obtain multiple patents that improperly claim the same invention or an obvious variation of an earlier claim.
In some situations, an applicant may overcome an obviousness-type double-patenting rejection by filing a terminal disclaimer. A terminal disclaimer can tie the later patent’s expiration date to the earlier patent and may require common ownership.
That means continuation and related-application practice is not a free way to obtain unlimited patent terms.
It is also important to distinguish a patent on a genuine improvement from a patent that merely changes the wording around an old invention.
Suppose a company has a successful product and files a new application after seeing exactly what its competitor has launched. If the claims appear to be drafted specifically to capture the competitor’s product without a real technical advance, the patent may face serious challenges.
Those challenges could involve lack of novelty, obviousness, inadequate disclosure, inequitable conduct, or other legal theories depending on the facts.
The prosecution history also matters. “Prosecution history” means the record of the applicant’s communications with the Patent Office, including amendments, arguments, and explanations of what makes the invention different from earlier technology.
Years later, a court or a competitor may examine that record. The company should be able to explain what problem each invention solved and why the claimed features were technically meaningful.
A strong patent strategy is not about filing applications forever just to keep a product surrounded by paperwork.
It is about matching patent filings to real development.
For a smaller company or startup, the same principle applies.
You do not have to invent an entirely unrelated product to file another patent. A later version of your product may be patentable if it solves a new technical problem or uses a genuinely new technical approach.
For example, version two of a device might:
operate with much less power;
function in a much harsher environment;
solve a reliability problem;
use a new mechanical arrangement; or
achieve a result that the earlier design could not achieve.
But simply changing the color, size, or appearance of a product may not be enough for a utility patent. And simply saying that a product is “better” does not establish non-obviousness.
The improvement needs to be connected to a technical invention.
There is also a business reason companies build large patent portfolios.
A company may use patents defensively. A large portfolio can help in negotiations, support cross-licensing, discourage lawsuits, or give the company options if a competitor files a lawsuit first.
That is generally legal. Patent rights are often used for negotiation, not just for courtroom enforcement.
The risk increases when a portfolio is built around weak applications, misleading statements, or attempts to block competition without genuine innovation.
Separate laws may also apply if a company uses patents as part of an anticompetitive scheme. But not every allegation of evergreening is an antitrust violation. Patentability and antitrust are different legal issues.
So, is patent evergreening legal?
The honest answer is: sometimes yes, and sometimes no.
It is generally lawful to obtain additional patents for real, new, non-obvious improvements to an existing product.
It may become problematic when the later patents cover obvious or insignificant changes, were obtained through deception, or are used as part of unlawful anticompetitive conduct.
The word “evergreening” does not answer the legal question. The substance of the invention and the conduct surrounding the patent do.
For inventors, the practical lesson is straightforward:
Keep improving your products. Document the technical problems you are solving. Record what changed between versions and why the change matters. Make sure each application is supported by a real invention and is drafted honestly and carefully.
Do not file another application merely because you want a patent to remain pending. File because you have a new technical contribution worth protecting.
To recap:
A product can be covered by multiple patents.
New patents on real improvements are not automatically improper.
Evergreening is a criticism or description, not a separate legal violation.
The important questions are novelty, non-obviousness, disclosure, validity, and how the patent is used.
A strong patent portfolio grows out of genuine innovation, not just strategic paperwork.
That’s it for today’s episode. If you need help filing a patent application or protecting other intellectual property, give me a call at 424-281-0162.
Until next time, I’m Adam Diament, and keep on inventing!