Litigation in Generic Pharmaceutical Markets: How Patent Disputes Delay Affordable Medicines

When a brand-name drug’s patent expires, you’d expect cheaper generic versions to hit the market quickly. But in reality, it often takes years longer than it should. Why? Because patent litigation has become a strategic tool-not just to protect innovation, but to block competition. In the generic pharmaceutical industry, legal battles over patents aren’t accidents. They’re calculated moves that delay affordable medicines and cost the U.S. healthcare system billions every year.

The Hatch-Waxman Act: A System Designed to Balance Innovation and Access

The foundation of today’s generic drug landscape is the Hatch-Waxman Act of 1984. It was meant to strike a balance: reward drug companies for inventing new medicines while making it easier for generics to enter the market after patents expire. The law created a streamlined approval process called the Abbreviated New Drug Application (ANDA). Generic manufacturers don’t need to repeat expensive clinical trials. They just need to prove their version is bioequivalent to the brand-name drug.

But there’s a catch. If a generic company believes a patent protecting the brand drug is invalid or won’t be infringed, they can file what’s called a Paragraph IV certification. This is essentially a legal challenge. And when they do, the brand company has 45 days to sue. If they do, the FDA is forced to delay approval of the generic for up to 30 months. That’s not a trial timeline. That’s a regulatory pause button.

This 30-month stay was never meant to be a permanent roadblock. But over time, it’s become the centerpiece of a much bigger game.

The Orange Book: Where Patents Are Listed-And Sometimes Abused

The FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations, better known as the Orange Book, is the official list of patents linked to brand-name drugs. Only certain types of patents belong there: those covering the active ingredient, specific formulations, methods of use, or manufacturing processes.

But here’s the problem: companies keep listing patents that don’t meet those criteria. Take the case of ProAir® HFA, an asthma inhaler. Teva filed an ANDA to make a generic version. The brand company, Alkermes, listed six patents related to the inhaler’s dose counter. In 2025, Judge Chesler in New Jersey ruled those patents didn’t claim the drug itself-albuterol sulfate-and had to be removed. That was a major win for generics.

But that’s just one case. According to the Association for Accessible Medicines (AAM), brand companies routinely list patents on packaging, delivery devices, or software used in inhalers and injectors. These aren’t protecting the medicine. They’re protecting market share.

Serial Litigation: The Slow-Motion Blockade

Some brand companies don’t just file one lawsuit. They file a series of them-each using a different patent, often one that was issued years after the original drug approval. This is called serial patent litigation.

AAM’s 2025 analysis tracked ten drugs where this tactic delayed generic entry by 7 to 10 years after the original patent expired. One drug, a treatment for a rare condition, had 14 separate patent challenges over 12 years. Each time a generic got close to approval, a new patent was asserted, triggering another 30-month stay.

This isn’t just legal noise. It’s a financial strategy. The FTC estimates that improper Orange Book listings delay generic entry for about 1,000 drugs every year. That costs the system $13.9 billion annually in extra spending.

Look at Eliquis (apixaban). It’s a blood thinner. The original patent expired in 2025. But the drug has 67 patents listed in the Orange Book. Semaglutide (Ozempic, Wegovy) has 152. These aren’t innovations-they’re legal fortresses.

Why the Eastern District of Texas Is the Patent Litigation Hotspot

Where these lawsuits get filed matters. In the past, Delaware and New Jersey were the go-to venues. But since 2023, the Eastern District of Texas has surged back to the top. In 2024, it handled 38% of all pharmaceutical patent cases-more than double the number in Delaware.

Why? Because it’s known for being plaintiff-friendly. Juries there tend to side with patent holders. Judges are experienced in complex patent law. And the court’s procedures favor early discovery and fast rulings on injunctions. For brand companies looking to drag out litigation, it’s the ideal courtroom.

Generic manufacturers hate it. They call it forum shopping. But with no federal rules limiting where suits can be filed, they’re stuck playing the game on the opponent’s turf.

Settlements: Pay-for-Delay or Faster Access?

One of the most controversial parts of this system is patent settlements. When a brand company sues a generic, they can settle before trial. Often, the generic agrees to delay market entry in exchange for a payment-or a deal to be the first generic on the market.

The FTC calls these “pay-for-delay” agreements and says they’re anti-competitive. They’ve challenged over 300 improper patent listings in 2024 alone and sent warning letters to 200 more in May 2025.

But here’s the twist: the IQVIA Institute found that these settlements actually speed up generic entry-on average, by more than five years before the patent expires. Why? Because without the settlement, the generic company might never file an ANDA at all. The risk of losing a multi-year lawsuit is too high. So they walk away.

John T. O’Donnell, an industry analyst, put it bluntly: “If you limit a generic drug manufacturer’s ability to settle cases, that manufacturer does not settle fewer cases. It submits fewer Paragraph IV ANDAs.”

So who’s right? The FTC? Or IQVIA? The truth is, both are seeing different sides of the same coin. Some settlements are abusive. Others are the only way generics can afford to enter the market.

Inter Partes Review: A New Weapon for Generics

Generic companies are fighting back with a different tool: inter partes review (IPR). This is a process at the Patent Trial and Appeal Board (PTAB) where a patent’s validity is re-examined by administrative judges-not a jury.

IPR filings against pharmaceutical patents jumped 47% from 2023 to 2024. It’s faster and cheaper than district court litigation. And it’s working. In 2024, over 60% of IPR petitions targeting brand drug patents resulted in the patent being invalidated or narrowed.

But there’s a new hurdle. In April 2025, the Supreme Court ruled in Smith & Nephew v. Arthrex that generic manufacturers need to show they’ll actually market the drug if the patent is invalidated. That’s a higher bar than before. Now, you can’t just file an IPR to scare the brand company-you have to prove you’re ready to compete.

What’s Changing in 2025 and Beyond

The tide is turning. In March 2025, the FTC and Department of Justice held joint listening sessions with 12 generic manufacturers. Testimony revealed brand companies listing patents on inhaler valves, packaging materials, and even software that controls dosing-none of which are related to the drug itself.

The FDA is responding. New regulations are coming in Q2 2026. Brand companies will have to certify under penalty of perjury that every patent they list in the Orange Book meets the legal standard. That’s a big deal. It means lying could mean criminal charges.

Skadden Arps estimates that 15-20% of currently listed patents could be removed under this new rule. That could open the door for hundreds of generics.

Meanwhile, the number of patents per drug keeps rising. For small molecule drugs, it’s now an average of 37. For biologics and biosimilars, it’s 78. Oncology drugs? Some have over 200. This isn’t innovation. It’s a legal arms race.

Who Pays the Price?

The real cost isn’t measured in legal fees or court rulings. It’s measured in lives. Patients who can’t afford their meds. Seniors skipping doses. Families choosing between insulin and rent.

The average time from brand drug approval to first generic entry has doubled since 2005-from 14 months to 28 months. For cancer drugs, it’s now over five years after patent expiration.

Law firms like Fish & Richardson and Quinn Emanuel are thriving. Their patent litigation practices grew 35-40% in 2024. Meanwhile, pharmacies are seeing fewer generic options. Insurance companies are paying more. And patients? They’re paying the most.

The Future: More Litigation, More Scrutiny

The Lex Machina 2025 report predicts pharmaceutical patent litigation will grow 25-30% annually through 2027. The complexity is only increasing. Biosimilars-generic versions of biologic drugs-are the next frontier. They’re harder to copy. And the patent thicket around them is even thicker.

But change is coming. The courts are starting to push back. The FDA is tightening rules. Congress is listening. And generics are getting smarter.

The question isn’t whether patent litigation will continue. It’s whether the system will finally be fixed to serve patients-not just profits.