Evergreening: How Pharmaceutical Brands Stretch Patents to Block Generic Drugs

When a blockbuster drug’s patent is about to expire, the company doesn’t just sit back and wait for cheaper generics to flood the market. Instead, they launch a quiet, legal, and often highly profitable campaign to delay that moment-sometimes for decades. This is evergreening: the practice of using minor changes to an existing drug to secure new patents and keep competitors out. It’s not about innovation. It’s about control.

How Evergreening Works

Every new drug gets a 20-year patent clock that starts when the patent is filed-usually years before the drug even hits shelves. By the time the FDA approves it, there might be only 7 to 12 years left on that clock. That’s not enough time to recoup the $2.6 billion it typically costs to develop a new drug. So companies turn to evergreening: filing new patents on tiny tweaks to the original product.

These aren’t breakthroughs. They’re adjustments: a new capsule shape, a slightly slower-release formula, a combination with another drug already on the market, or a switch from a pill to a liquid. The FDA doesn’t require these changes to be more effective-just different enough to qualify for a new patent. And under the Hatch-Waxman Act of 1984, each new patent can add years of market exclusivity.

For example, AstraZeneca’s heartburn drug Prilosec (omeprazole) was a top seller. When its patent neared expiration, they launched Nexium (esomeprazole)-a version with one slightly altered molecule. Nexium wasn’t proven to work better. But it carried a new patent. And suddenly, patients were paying up to 10 times more for what was essentially the same drug.

The Tools of the Trade

Pharmaceutical companies don’t rely on one trick. They build a whole toolkit:

• Product hopping: Replacing the original drug with a new version that’s hard to switch from-like switching from a pill to an inhaler or a once-daily tablet. Patients and doctors get used to the new form, and generics can’t easily replace it.
• Patent thickets: Filing dozens, even hundreds, of patents around a single drug. AbbVie filed 247 patents for Humira, its autoimmune drug. Even if one patent is challenged, 246 others remain in place, creating a legal maze that generic makers can’t afford to navigate.
• Authorized generics: The brand company itself releases a cheaper version under a different label, just before generics arrive. This floods the market with a low-priced option, making it unprofitable for independent generics to enter.
• Orphan drug extensions: Applying for orphan drug status by targeting a small patient group, which grants seven years of exclusivity-even if the drug treats a common condition in larger populations.
• Pediatric exclusivity: Running small studies on children to earn six extra months of protection. This doesn’t mean the drug is better for kids-it just means the clock gets pushed back.

These aren’t loopholes. They’re features of the system.

Why It’s So Profitable

Developing a brand-new drug costs billions. Evergreening? A fraction of that. A new formulation might cost $50 million to develop and test. But the payoff? Billions in extra revenue.

Humira, for example, made $21 billion in sales in 2023 alone. Because of its patent strategy, no generic version has been approved in the U.S. until late 2023-19 years after its launch. That’s nearly double the original patent term. AbbVie made over $150 billion from Humira in total, thanks to these extensions.

AstraZeneca’s six top drugs were protected for over 90 extra years combined. That’s not innovation. That’s financial engineering.

The Human Cost

Every year a drug stays off the market as a generic, patients pay more. Generic drugs typically cost 80-85% less than brand-name versions. When evergreening blocks that drop, people choose between their medicine and rent.

Diabetes, heart disease, arthritis-these are common, chronic conditions. Millions rely on drugs like omeprazole, metformin, or Humira. When prices stay high, patients skip doses, split pills, or go without. Studies show this leads to more hospital visits, worse outcomes, and higher overall healthcare costs.

In low- and middle-income countries, the impact is even harsher. A drug protected by evergreening in the U.S. might be unaffordable or unavailable elsewhere. The WHO has called this a barrier to global health equity.

Who’s Fighting Back?

Regulators and courts are starting to push back.

In 2022, the U.S. Federal Trade Commission sued AbbVie over Humira’s patent strategy, calling it an illegal monopoly. The FTC argued the 247 patents were a deliberate tactic to block competition-not to protect real innovation.

The Inflation Reduction Act of 2022 gave Medicare the power to negotiate prices for the most expensive drugs. If the government can cap prices, the financial incentive for evergreening weakens.

The European Medicines Agency now requires companies to prove a new version offers “significant clinical benefit” before granting extra protection. That’s a big shift. In the U.S., the USPTO has also tightened rules on obviousness, making it harder to patent minor changes.

But the industry fights back with lobbyists, legal teams, and PR campaigns. Every time a court rules against a patent, another one is filed.

Is There a Better Way?

Some experts argue the system should reward real innovation, not legal gymnastics. Instead of letting companies extend patents on old drugs, they propose a prize system: pay companies a lump sum for breakthroughs, then let generics compete immediately.

Others suggest limiting patent extensions to drugs that truly improve patient outcomes-not just change the color of a pill. If a new version doesn’t reduce side effects, improve effectiveness, or make dosing easier, it shouldn’t get extra exclusivity.

The data shows 78% of new drug patents are for existing drugs-not new ones. That’s not innovation. It’s maintenance.

What’s Next?

The next wave of evergreening is already here. Companies are patenting nanotech versions of drugs, genetic tests that predict who responds to a medication, and biologic versions that are harder to copy than traditional pills. These aren’t just tweaks-they’re technical barriers designed to keep generics out for another 20 years.

Meanwhile, patients keep paying. Doctors keep prescribing. And the cycle continues.

The question isn’t whether evergreening works. It does-brilliantly for shareholders. The real question is: who’s paying the price?