How pharmaceutical companies use secondary patents to keep drugs expensive
When a drug first hits the market, it usually has one big patent protecting the active ingredient. That patent lasts 20 years from the day it’s filed. But by the time the drug gets approved by regulators, five or six years might already be gone. That leaves maybe 14 years of real market exclusivity before generics can appear. That’s not enough for some companies. So they file secondary patents-dozens of them-to push back generic competition for years, sometimes decades.
These aren’t new drugs. They’re not cures. They’re tweaks. A different salt form. A new pill coating. A slightly different dose. A new use for an old medicine. And each one adds another layer of legal protection. This isn’t accidental. It’s a calculated strategy called pharmaceutical lifecycle management. Companies like Pfizer, AbbVie, and AstraZeneca have turned this into a science.
What exactly counts as a secondary patent?
Secondary patents cover everything except the core chemical compound. Think of them as accessories to the main product. The U.S. Food and Drug Administration recognizes over a dozen types, but a few dominate:
- Formulation patents protect how the drug is made-tablet, capsule, liquid, or slow-release. AstraZeneca’s Nexium, a single-enantiomer version of Prilosec, was patented this way. Even though both drugs treat the same condition, Nexium cost twice as much. It delayed generics by nearly eight years.
- Method-of-use patents claim a new medical application. Thalidomide was originally a sedative. Decades later, it got a new patent for treating leprosy. Then another for multiple myeloma. Each patent reset the clock.
- Polymorph patents protect different crystal structures of the same molecule. GlaxoSmithKline’s Paxil used this trick. The original patent expired in 2001, but a specific crystal form (Form G) was patented in 1997. Generics couldn’t enter until 2005.
- Combination patents bundle two or more drugs together. This is common in HIV and diabetes treatments. Even if each drug is old, putting them in one pill gets a new patent.
Some companies file more than 100 secondary patents on a single drug. AbbVie’s Humira, the world’s best-selling drug for years, had 264 secondary patents. The main patent expired in 2016. But because of this web of patents, generics didn’t arrive in the U.S. until 2023. During that gap, Humira brought in over $20 billion a year.
Why does this matter to patients and payers?
For patients, it means higher prices. For insurers and Medicare, it means ballooning costs. Pharmacy benefit managers like Express Scripts say secondary patents increase their annual drug spending by about 8.3%. In the U.S., where drug prices are among the highest in the world, this pattern is everywhere.
Doctors report being pressured to switch patients to newer versions right before generics hit. It’s called product hopping. A patient stable on a $50 generic might be moved to a $400 branded version with a new coating or slightly different dose. The clinical difference? Often negligible. But the profit margin? Huge.
Patient advocacy groups point to Humira and Enbrel as textbook cases. These drugs could’ve become cheap generics years ago. Instead, patients paid billions more than necessary. The American Cancer Society, however, acknowledges that some secondary patents do deliver real benefits-like reduced side effects or easier dosing. But those cases are the exception, not the rule.
How do generic companies fight back?
Generic manufacturers don’t sit idle. When a drug’s primary patent expires, they file what’s called a Paragraph IV certification. This is a legal challenge saying the secondary patents are invalid or won’t be infringed. In 2022, 92% of listed secondary patents faced these challenges.
But winning is hard. Only about 38% of these challenges succeed in court. Why? Because the patent system favors the brand-name companies. They have teams of 15 to 20 patent lawyers per major drug. They spend $12-15 million per secondary patent application. They file early, file often, and bury generics in legal paperwork.
It’s not just about money. It’s about time. Generic companies say navigating a patent thicket adds an average of 3.2 years to their time-to-market. Legal costs per product? $15-20 million. That’s a huge barrier for smaller firms. The result? Fewer competitors. Higher prices. Longer delays.
The global divide: Where secondary patents are blocked
Not every country lets this happen. India’s patent law, since 2005, explicitly blocks patents on new forms of known drugs unless they show “enhanced efficacy.” That’s why Novartis lost its fight to patent a new crystalline form of Gleevec in 2013. The Indian Supreme Court ruled it was just a minor change.
Brazil requires health ministry approval before a pharmaceutical patent can be enforced. The European Union demands “significant clinical benefit” for some secondary patents. These rules aren’t perfect, but they prevent the worst abuses.
In contrast, the U.S. system under the Hatch-Waxman Act of 1984 was meant to balance innovation and access. But over time, courts and companies have stretched it beyond its original intent. The U.S. now leads the world in secondary patent filings.
The economic impact: Who benefits?
The numbers don’t lie. Drugs earning over $1 billion a year are 89% more likely to have 10 or more secondary patents. For drugs under $100 million? Only 22% do. This isn’t about innovation-it’s about revenue.
According to Evaluate Pharma, top-selling drugs make 58% of their total lifetime revenue during their secondary patent period. That’s longer than the initial patent window. Pfizer alone held over 14,200 active secondary patents as of mid-2023. That’s not just strategy-it’s a business model.
PhRMA, the industry’s main lobby, argues these patents fund future research. They say follow-on innovations improve safety and dosing. And yes, some do. But a 2016 Harvard study found only 12% of secondary patents offered meaningful clinical improvements. The rest? Just legal padding.
Meanwhile, the U.S. government is starting to push back. The 2022 Inflation Reduction Act gave Medicare new power to challenge certain secondary patents. The European Commission’s 2023 Pharmaceutical Strategy targets patent thickets as a barrier to access. The World Health Organization now calls secondary patents the #1 legal tool delaying generic medicines in low- and middle-income countries.
What’s next? The future of secondary patents
The tide may be turning. Courts are applying stricter tests for obviousness. The 2023 Amgen v. Sanofi decision limited how broadly antibody patents can be claimed. That could ripple into other areas of secondary patenting.
Industry analysts predict filings will keep growing-around 5.8% per year through 2028. But the pressure is mounting. Patients are angry. Politicians are talking. Insurers are pushing back. And generic companies are getting smarter.
Companies that survive will need to show real value-not just legal tricks. As Dr. Roger Longman of Windhover Information said, “By 2027, successful pharmaceutical companies will need to demonstrate that secondary patents correspond to meaningful clinical improvements to maintain public and regulatory support.”
The question isn’t whether secondary patents will disappear. They won’t. But their scope, their justification, and their legal protection are under siege. The next decade will decide whether they’re tools of innovation-or tools of exploitation.
Are secondary patents legal?
Yes, secondary patents are legal in most countries, including the U.S., Canada, and the EU. But their validity depends on whether they meet patentability standards-novelty, non-obviousness, and utility. Many are challenged in court, and some are struck down when courts find they’re just minor changes without real innovation.
How long do secondary patents last?
Like primary patents, secondary patents last 20 years from the filing date. But because they’re often filed years after the original patent, they can extend total market exclusivity by 4-11 years beyond the original patent’s expiration. Some drugs end up with over 20 years of protection thanks to layered secondary patents.
Do secondary patents improve patient outcomes?
Sometimes. A few secondary patents lead to real benefits-like fewer side effects, easier dosing, or better absorption. But studies show only about 12% of secondary patents offer clinically meaningful improvements. Most are minor formulation tweaks designed to delay generics, not enhance therapy.
Why do generic drug makers struggle to enter the market?
Because brand-name companies file dozens of secondary patents, often covering everything from pill coatings to new uses. Generic manufacturers must challenge each one in court, which takes years and costs $15-20 million per drug. Many can’t afford it. Even when they do, success rates are low-only 38% of legal challenges win.
Which countries restrict secondary patents?
India and Brazil are the most notable. India’s Section 3(d) of the Patents Act blocks patents on new forms of known drugs unless they show significantly enhanced efficacy. Brazil requires health ministry approval before patents can be enforced. The EU also demands proof of “significant clinical benefit” for certain types. These rules help keep drug prices lower.
Can Medicare challenge secondary patents now?
Yes. The 2022 Inflation Reduction Act gave Medicare the authority to negotiate drug prices and challenge certain secondary patents it considers unjustified. This is a major shift-previously, Medicare couldn’t dispute patent validity. It’s still early, but this could weaken the power of patent thickets over time.
What can be done?
There’s no single fix. But progress is happening. Stronger patent standards, transparency in patent listings, and limits on evergreening could help. Countries like India prove that smarter patent laws can open the door to affordable medicines without killing innovation.
For now, the system favors companies that play the game well. The real winners aren’t the patients who need the drugs. They’re the shareholders who benefit from prolonged monopolies. The question is whether society will keep letting that happen-or start demanding better.
Geri Rogers
February 3, 2026 AT 19:01