By 2028, one of the most profitable drugs in history - Keytruda - will lose its patent protection. That’s not just a legal event. It’s a seismic shift in how cancer care is paid for, prescribed, and accessed across the U.S. and beyond. Keytruda brought in $25.5 billion in sales in 2024. When biosimilars enter the market, that number will drop - fast. And it’s not just Keytruda. Dozens of high-cost biologic drugs are hitting patent cliffs between now and 2030, opening the door for cheaper, equally effective alternatives. This isn’t about generics. This is about biosimilars - and what’s coming next.
What Exactly Are Biosimilars?
Biosimilars aren’t copies like generic pills. They’re complex, living medicines made from living cells. Think of them as near-identical twins to original biologic drugs like Humira, Eylea, or Keytruda. These drugs treat cancer, autoimmune diseases, and other serious conditions. Because they’re made from proteins, not chemicals, you can’t just mix the same ingredients in a lab. You need living cells, precise conditions, and years of testing to prove they behave the same way in the body. The FDA requires biosimilars to show no clinically meaningful differences in safety, purity, or potency compared to the original. That means they must match the original drug’s structure, how it binds to targets, and how it’s processed by the body. For example, a Keytruda biosimilar must replicate the exact sugar patterns (glycosylation) on its antibody. Get that wrong, and it might not work as well in fighting tumors. Unlike generics, which can be approved with simple bioequivalence studies, biosimilars need full analytical testing, animal studies, and often a clinical trial. The process takes 7-10 years and costs $150-250 million per product. That’s why only a handful of companies - Sandoz, Samsung Bioepis, Biocon, Celltrion - are doing this at scale.The Patent Cliff: What’s Expanding in the Next Five Years?
Between 2025 and 2030, over $200 billion in annual global sales for biologic drugs will lose patent protection. That’s more than the GDP of many countries. Here’s what’s coming:- Eylea (aflibercept) - Expiration in 2025. Already, three biosimilars (Yesafili, Opuviz, Enzeevu) are on the market. Sales were $5.9 billion in the U.S. in 2023.
- Enbrel (etanercept) - Expiration in 2023. Biosimilars now make up 80% of new prescriptions. Launched at 35% discount.
- Cosentyx (secukinumab) - U.S. patent expires in 2029. Samsung Bioepis’ biosimilar got EU approval in late 2025 and will enter the U.S. shortly after.
- Keytruda (pembrolizumab) - Patent expires in 2028. 14 companies are already in Phase 3 trials. This is the biggest prize.
- Humira (adalimumab) - Patent expired in 2023. 12 biosimilars now approved. Adoption hit 80% of new prescriptions within 18 months.
Why Are Biosimilars Cheaper? And How Much Do They Save?
Biosimilars cost less because they don’t need to repeat the original clinical trials that proved safety and effectiveness. They rely on the reference drug’s data. That cuts development time and cost dramatically. They typically launch at 15-35% discounts. In some cases, like Enbrel, the discount was 35% from day one. In others, like Eylea biosimilars, pricing started at 20-25%. But discounts aren’t just about sticker price. They ripple through the entire system. The RAND Corporation estimates biosimilars could save the U.S. healthcare system $250 billion over the next decade. The Congressional Budget Office says Medicare alone will save $51 billion from 2026 to 2035. That’s enough to cover millions of insulin prescriptions, cancer treatments, or rheumatoid arthritis therapies for patients who currently can’t afford them. But here’s the catch: savings don’t always reach patients. Medicare Part B reimburses providers based on the drug’s average sales price (ASP). That means if a doctor gives a $10,000 reference drug, they get paid more than if they give a $7,000 biosimilar - even if the outcome is identical. So some providers still push the expensive version. That’s why some health systems have started mandatory substitution policies. Kaiser Permanente, for example, switched all new filgrastim prescriptions to biosimilars in 2024. Usage jumped from 12% to 68% in six months.
Who’s Winning the Biosimilar Race?
The market is consolidating fast. In August 2024, Novartis’ Sandoz bought Biocon’s biosimilars business for $3.9 billion. That made Sandoz the global leader with 28% market share. Samsung Bioepis is close behind, with products approved in the U.S., EU, and Canada. Celltrion and Biocon are expanding aggressively in Asia and Latin America. Originator companies aren’t sitting still. Merck, which makes Keytruda, has over 200 patents on the drug, some extending protection to 2035. They’re using legal tactics - patent thickets, litigation, and pediatric exclusivity extensions - to delay competition. Bristol Myers Squibb did the same with Eliquis, pushing its patent life to 2029. But even they’re adapting. Regeneron partnered with Alvotech in January 2025 to develop authorized biosimilars for Eylea. Pfizer teamed up with Mylan to form Viatris, a dedicated biosimilar commercialization arm. These aren’t just competitors - they’re becoming part of the ecosystem.Why Is Adoption Slower in the U.S. Than in Europe?
In Europe, biosimilars make up over 70% of use for some drugs. In the U.S., it’s closer to 30-40%. Why the gap? First, reimbursement. Europe’s single-payer systems can negotiate prices directly. The U.S. has a fragmented system with insurers, PBMs, and pharmacy benefit managers all taking cuts. Rebates often go to middlemen, not patients. Second, physician trust. Many U.S. doctors still worry about switching patients from the original drug. A 2024 survey by the Cancer Support Community found 34% of patients were confused about whether biosimilars were safe to use. Some clinicians still see them as “second-tier.” Third, the “patent dance.” Legal battles over patent listings delayed Humira biosimilars for nine years. The FDA’s January 2025 rule now requires real-time patent updates, which should reduce these delays. But the damage is done - and trust takes longer to rebuild.
Real-World Impact: What Are Doctors and Patients Seeing?
At the American Society of Clinical Oncology in 2024, Dr. Laura Chow reported no difference in outcomes between Humira and its biosimilars in inflammatory bowel disease patients. That’s huge. Real-world data is finally catching up to clinical trials. But there are warnings too. Dr. Richard Pazdur at the FDA’s Oncology Center documented rare immune reactions when patients switched between different rituximab biosimilars. That’s why interchangeability matters. Only 12 biosimilars in the U.S. are FDA-designated as “interchangeable” - meaning a pharmacist can substitute them without the prescriber’s permission. That number is growing, but slowly. Pharmacists are seeing progress. CVS Caremark reported a 22% drop in prior authorization denials for biosimilars in Q2 2025. That means fewer delays for patients. But academic medical centers still struggle to track long-term outcomes across multiple biosimilar versions. EHR systems aren’t always updated to distinguish between them.What’s Next? The Future of Biosimilars
The next wave isn’t just about copying old drugs. It’s about making better ones. The FDA’s 2025 draft guidance on “Analytical Similarity for Highly Complex Biologics” is paving the way for biosimilars of antibody-drug conjugates - drugs that carry chemotherapy directly to cancer cells. These are even more complex than monoclonal antibodies. Payers are pushing hard. Centene’s 2025 formulary now requires biosimilars for all new patients on TNF inhibitors. Cigna’s Medicare Advantage plans offer $0 copays for biosimilars versus $50 for the original. That’s a powerful incentive. The global biosimilars market hit $12.7 billion in 2024. By 2030, it’s expected to hit $80 billion. The U.S. will account for nearly half of that, even though it’s been slow to start. The big question isn’t whether biosimilars will come. They’re already here. The question is: will the system let them save money - or will old incentives keep patients paying more than they should?For patients, the message is simple: ask if a biosimilar is right for you. For providers, it’s time to update your protocols. For payers, it’s time to fix the reimbursement system. And for the industry - the patent cliff isn’t a threat. It’s an opportunity to make care more affordable, accessible, and fair.
Are biosimilars the same as generics?
No. Generics are chemically identical copies of small-molecule drugs like aspirin or metformin. Biosimilars are complex proteins made from living cells. They’re highly similar to their reference biologic but not identical. Because of their complexity, they require more testing to prove safety and effectiveness.
When will Keytruda biosimilars be available?
Keytruda’s main patent expires in 2028. Fourteen companies are already in Phase 3 trials. The first biosimilars could be approved in late 2027 or early 2028, with market entry likely by mid-2028. Merck has over 200 patents on Keytruda, so some legal delays are possible - but the FDA is moving faster now to prevent patent thickets from blocking competition.
How much cheaper are biosimilars than the original drugs?
Biosimilars typically launch at 15-35% lower prices than the reference product. For example, the Enbrel biosimilar launched at a 35% discount. Eylea biosimilars started at 20-25% off. The actual savings depend on negotiations between manufacturers, insurers, and pharmacy benefit managers. Some patients pay $0 out-of-pocket if their plan favors biosimilars.
Can pharmacists substitute biosimilars without a doctor’s approval?
Only if the biosimilar is FDA-designated as “interchangeable.” As of early 2026, only 12 biosimilars in the U.S. have this status. For non-interchangeable biosimilars, the prescriber must specifically write the biosimilar name on the prescription. Interchangeable status requires extra data proving that switching between the original and biosimilar won’t affect safety or effectiveness.
Why are biosimilars taking so long to enter the U.S. market?
Several factors: complex patent litigation (like the 9-year delay for Humira biosimilars), reimbursement systems that financially reward higher-priced drugs, lack of physician confidence, and slow updates to electronic health records. The FDA has been speeding up approvals - from 5 per year in 2020 to 17 in 2024 - but the system behind the scenes hasn’t caught up yet.
Will biosimilars make cancer treatment more affordable?
Yes - if the system allows it. Keytruda alone costs over $150,000 per year. A 30% discount could save patients $45,000 annually. With 14 biosimilars in development for Keytruda, prices could drop even further. But without changes to Medicare reimbursement and insurance policies, savings may go to insurers and hospitals instead of patients. Real affordability depends on policy, not just science.