By 2028, the biggest drug in the world could lose its patent protection - and with it, the chance for patients and insurers to save billions. Keytruda, Merck’s cancer immunotherapy, brought in $25.5 billion in sales in 2024. But soon, multiple biosimilars will hit the market, offering the same treatment at a fraction of the cost. This isn’t just about one drug. It’s the start of a wave. Between 2025 and 2030, over $200 billion in annual global sales from top biologics will become open for competition. And the players are already in position.
What Exactly Are Biosimilars?
Biosimilars aren’t generics. That’s the first thing to understand. Generics are exact copies of small-molecule drugs - think aspirin or metformin. Biosimilars are copies of biologics, which are made from living cells. These are complex proteins, often antibodies, that target specific diseases. They’re used to treat cancer, autoimmune disorders like rheumatoid arthritis, and rare conditions. Because they come from living systems, no two batches are perfectly identical. That’s why biosimilars aren’t called “copies” - they’re “highly similar.” The FDA requires biosimilars to show no clinically meaningful difference in safety, purity, or potency compared to the original. That means rigorous testing - thousands of lab analyses, animal studies, and sometimes human trials. It’s not easy. A single biosimilar can take 7 to 10 years and $150-250 million to develop. But the payoff is huge: biosimilars typically launch at 15-35% lower prices than the reference product.The Patent Cliff Is Here
The next five years are a perfect storm of expiring patents. The biggest targets? Drugs that made billions for their makers and are now used by millions.- Eylea (aflibercept) - Used for macular degeneration and diabetic eye disease. Patents expired in 2025. Three biosimilars - Yesafili, Opuviz, and Enzeevu - were approved in 2024. By Q1 2025, they already made up 12% of U.S. prescriptions.
- Humira (adalimumab) - The former top-selling drug in the world. Its patents expired in 2023. Twelve biosimilars are now on the market. In just 18 months, they captured 80% of new prescriptions.
- Enbrel (etanercept) - A rheumatoid arthritis staple. Sandoz launched its biosimilar in 2023 at a 35% discount. Within a year, hospital systems switched over 60% of patients.
- Keytruda (pembrolizumab) - The cancer immunotherapy giant. Its main patent expires in 2028. Fourteen companies are already in Phase 3 trials. This could be the biggest biosimilar launch in history.
Why Are Biosimilars So Much Cheaper?
It’s not because they’re lower quality. It’s because the original companies spent decades and billions developing the first version. They had to prove the drug worked, figure out how to make it consistently, and navigate regulatory hurdles. Biosimilar makers don’t have to do that. They can build on the reference product’s data. That cuts development time and cost dramatically. But here’s the catch: manufacturing biosimilars is still expensive. These are large, fragile molecules. One small change in temperature or pH during production can alter how the drug behaves in the body. That’s why companies like Samsung Bioepis spent $450 million building a single facility in South Korea just to make biosimilars. It’s not a simple vat and a filter. It’s a precision science operation.
Who’s Winning the Biosimilar Race?
The field is crowded, but a few names stand out:- Sandoz (Novartis) - The market leader with 28% share after buying Biocon’s biosimilars business in 2024. They’ve got 10+ biosimilars on the market, including Enbrel and Zarxio.
- Samsung Bioepis - A powerhouse in Korea. Their biosimilars are approved in the U.S., EU, and Canada. They’re the main force behind the upcoming Keytruda and Cosentyx biosimilars.
- Celltrion - Korean company with strong EU presence. Their infliximab biosimilar (Remsima) is one of the most widely used outside the U.S.
- Biocon Biologics - India-based, now partnered with Mylan (Viatris). Their Yesafili for Eylea was the first FDA-approved biosimilar in 2024.
- Alvotech - A rising star. Signed a $1.2 billion deal with Regeneron in early 2025 to develop biosimilars for Eylea and other drugs.
The U.S. Lags Behind Europe - But Is Catching Up
Europe has had biosimilars since 2006. Today, over 70% of patients on biologics in countries like Germany and Sweden get biosimilars. In the U.S., adoption is still around 30-40%. Why the gap? One big reason: reimbursement. Medicare Part B pays providers based on the drug’s average sales price (ASP). If a provider gives a $10,000 reference drug, they get reimbursed $10,500 (ASP + 6%). If they give a $6,500 biosimilar, they get $6,890. That means they make less money per dose - even though the drug works just as well. So some doctors stick with the pricier option. Payers are fighting back. Cigna’s 2025 Medicare Advantage plans now offer $0 copays for biosimilars and $50 for the brand. Centene requires biosimilars for all new patients on TNF inhibitors. CVS Caremark saw a 22% drop in prior authorization denials for biosimilars in early 2025. That’s a sign insurers are finally pushing hard for savings.
Challenges - Not All Biosimilars Are Equal
There’s a big difference between switching a patient from Humira to a biosimilar and switching from Keytruda. Humira treats chronic inflammation. The immune system isn’t as sensitive to tiny changes. But Keytruda is used in cancer. It’s a monoclonal antibody that needs to bind perfectly to a receptor on tumor cells. Even a slight change in sugar molecules (glycosylation) could affect how well it works. Some doctors are cautious. Dr. Richard Pazdur from the FDA’s Oncology Center noted in a 2024 study that a few patients had unexpected immune reactions when switching between different rituximab biosimilars. That’s why the FDA doesn’t yet allow automatic substitution for most oncology biosimilars - the prescriber must specifically write “dispense as written.” Patient confusion is another issue. A 2024 survey by the Cancer Support Community found 78% of patients were happy with the cost savings - but 34% didn’t understand how substitution worked. Many thought their doctor had changed their medication without telling them.What’s Next? The Road to 2030
The FDA approved 17 biosimilars in 2024 - up from just 5 in 2020. That’s acceleration. Their 2025 draft guidance on “Analytical Similarity” aims to speed up approvals for even more complex drugs, like antibody-drug conjugates. The Purple Book, which lists all approved biosimilars and their patents, is now updated daily. That’s huge. For years, patent thickets delayed biosimilars - Humira’s entry was blocked for 9 years by legal maneuvering. Now, the FDA is forcing companies to list patents in real time. The Congressional Budget Office estimates Medicare will save $51 billion between 2026 and 2035 from upcoming biosimilar entries. But that depends on fixing reimbursement rules. If providers still profit more from expensive drugs, adoption will stall. By 2030, the global biosimilars market is projected to hit $80 billion. The U.S. will account for nearly half of that. Keytruda’s entry in 2028 will be the tipping point. If it succeeds, every other blockbuster biologic - from Eliquis to Stelara - will follow. This isn’t just about cheaper drugs. It’s about access. Right now, many patients can’t afford biologics. Biosimilars could make life-saving treatments available to millions who’ve been priced out. The science is ready. The patents are expiring. The question now is whether the system will let patients benefit.Are biosimilars safe?
Yes. The FDA requires biosimilars to prove no clinically meaningful difference in safety, effectiveness, or purity compared to the original biologic. Thousands of lab tests, animal studies, and often human trials are required before approval. Millions of patients worldwide have used biosimilars safely for over a decade.
Can I switch from a biologic to a biosimilar?
For many conditions like rheumatoid arthritis or Crohn’s disease, switching is common and safe. For cancer drugs like Keytruda, switching is possible but requires your doctor’s approval. The FDA doesn’t allow automatic substitution for most oncology biosimilars - your prescription must say “dispense as written.” Always talk to your doctor before switching.
Why are biosimilars cheaper if they’re just as good?
The original biologic company spent decades and billions developing the drug, running trials, and building manufacturing systems. Biosimilar makers don’t have to repeat those steps. They use the original’s data to prove similarity, which cuts development time and cost. That savings gets passed on - usually as 15-35% lower prices.
How do I know if my drug has a biosimilar?
Check the FDA’s Purple Book, which lists all approved biosimilars and their reference products. Your pharmacist can also tell you if a biosimilar is available and if substitution is allowed. Most insurers now have biosimilar options listed in their formularies.
Will biosimilars replace all biologics?
Not entirely. Newer biologics with novel mechanisms - like those targeting rare genetic diseases - may be harder to copy. But for the major blockbuster drugs used for cancer, arthritis, and diabetes, biosimilars are expected to become the standard. By 2035, analysts project they’ll capture 65-75% of the market for expired biologics.
