When the FDA approves a generic drug, you might assume it’ll hit pharmacy shelves soon after. But in reality, many approved generics sit on the shelf for years - not because they’re unsafe, not because they’re untested, but because of patent litigation. Between 2023 and 2025, this delay became the norm, not the exception.
Why Approved Generics Don’t Reach Patients
The FDA approved 63 first generics in 2025, according to GoodRx. That sounds like progress. But here’s the catch: the average time between FDA approval and actual market launch is now 3.2 years. That’s more than three full years of patients paying full price for brand-name drugs while cheaper versions sit idle. The main reason? The 30-month statutory stay. When a generic company files an Abbreviated New Drug Application (ANDA) and challenges a patent with a Paragraph IV certification, the brand-name manufacturer can sue. Once they do, the FDA can’t give final approval until 30 months pass - or the court rules in favor of the generic. Even if the patent is weak, the clock keeps ticking. That’s not a safety rule. It’s a legal delay tactic.Patent Thicketing: The Real Enemy
Brand-name companies aren’t just defending one patent anymore. They’re stacking them. In 2020, the average New Drug Application listed 12.3 patents. By 2025, that number jumped to 14.7. Some drugs now have over 20 patents listed in the FDA’s Orange Book. Take Humira. Its core patent expired in 2016. But AbbVie filed dozens of follow-up patents on delivery methods, dosing regimens, and formulations. Each one triggered a new 30-month stay. The result? Humira kept its monopoly until 2023 - seven years past its original patent expiry. That’s not innovation. That’s patent thicketing. Dr. Aaron Kesselheim from Harvard Medical School put it bluntly: “The current patent thicketing strategies have extended monopolies beyond the intended 20-year term by an average of 3.7 years per drug.”Who Gets Hurt the Most?
Patients. Pharmacists. Hospitals. Medicare. A 2025 survey by the Association for Accessible Medicines found that 82% of pharmacists regularly get asked by patients why a drug they’ve been told is “approved” still isn’t available. Top offenders? Eliquis, Trulicity, Steglatro, and Xarelto. One pharmacist on Drugs.com wrote: “We had the generic for Xarelto approved last November. But the brand company filed three new patents last month. Now we’re looking at another 30-month delay.” Patients For Affordable Drugs Now documented 412 cases between 2023 and 2025 where people skipped doses or went without medication because generics weren’t on the shelf. The brand-name version cost an average of $487 per month. The generic? Projected at $85. Medicare Part D spent $3.2 billion more than it should have in 2025 because of these delays, according to the Congressional Budget Office.
Complex Generics Face Longer Delays
Not all generics are created equal. Simple oral pills - like metformin or lisinopril - move faster. But injectables, inhalers, and complex formulations? They’re stuck. In 2025, 89% of delayed complex generics faced patent-related blocks. Compare that to just 63% of simple oral solids. Oncology drugs are the worst. The average delay between FDA approval and market launch for cancer generics? 4.1 years. Why? These drugs require more complex manufacturing. But the real bottleneck isn’t production - it’s patents. One 2025 PMC study found 14 out of 15 oncology drug shortages between 2023 and 2025 were tied to patent litigation, not supply chain issues.Supply Chains Are a Secondary Problem
Yes, supply chain problems exist. In 37% of delayed generic launches, manufacturers cited issues with Active Pharmaceutical Ingredients (API). Many of these APIs come from India or China, and disruptions there can slow things down. But here’s the key: even when supply chains are stable, patent litigation still holds up 72% of all delays, according to Drug Patent Watch. That’s more than supply, more than FDA backlog, more than manufacturing issues combined. Leading companies like Teva and Sandoz are responding by diversifying their API suppliers. In 2022, they averaged 1.8 approved suppliers per drug. By 2025, that number rose to 3.4. It’s a smart move - but it doesn’t fix the patent problem.The U.S. vs. The Rest of the World
The U.S. is the outlier. In Europe, the average time between generic approval and market launch is just 1.7 years. Why? No 30-month stay. No patent litigation that automatically freezes approval. Europe’s system lets generics enter as soon as they’re approved - unless a court rules the patent is valid. In the U.S., the system is designed to favor brand companies. The 30-month stay was meant to be a temporary pause. Now it’s a weapon. And it’s being used aggressively. Biosimilars are following the same pattern. Humira alone had 242 patents challenged in litigation. That created a 10-year exclusivity window. But even with that, 17 biosimilars were approved by Q3 2025. The system is strained, but not broken.