When your doctor talks about a new medicine for your arthritis, diabetes, or cancer, you might hear the word biosimilar. It sounds technical, maybe even scary. But here’s the truth: biosimilars aren’t experimental or second-rate. They’re carefully made copies of powerful biologic drugs - and they’ve been used safely by millions of people around the world.
What’s the difference between a biosimilar and a regular generic drug?
If you’ve taken a generic version of aspirin or cholesterol medicine, you’re used to generics. Those are small, simple chemicals made in a lab. They’re exact copies of the brand-name version. If you switch from Lipitor to atorvastatin, you’re getting the same molecule, every time.
Biosimilars are nothing like that.
Biologic drugs - the ones biosimilars copy - are made from living cells. Think of them like a complex recipe using yeast, bacteria, or animal cells to grow proteins that treat disease. These proteins are huge, delicate structures. Even tiny changes in how they’re made - the temperature, the type of cell, the purification process - can change how they behave in your body.
That’s why a biosimilar isn’t an exact copy. It’s a highly similar version. Think of it like two handmade wooden chairs from the same designer. They look almost identical, feel the same, and serve the same purpose. But no two handmade chairs are 100% identical. And that’s okay - as long as they work the same way.
How do we know biosimilars are safe?
The U.S. Food and Drug Administration (FDA) doesn’t approve biosimilars lightly. Before a biosimilar reaches patients, it goes through more than 100 different tests.
Scientists compare the biosimilar to the original biologic at the molecular level - checking its shape, size, and chemical makeup. Then they test it in animals. Finally, they run clinical trials with hundreds of patients to make sure it works the same way, causes the same side effects, and is just as safe.
For example, the biosimilar Renflexis, used for rheumatoid arthritis, was tested in 541 patients before approval. Studies from Europe, where biosimilars have been used for over a decade, show no unexpected safety issues. The FDA says: "Biosimilars are as safe and effective as their reference products."
And here’s something important: switching from the original biologic to a biosimilar has been studied and proven safe. If your doctor suggests the switch, it’s not a gamble. It’s science-backed.
What conditions are biosimilars used for?
Biosimilars aren’t just for one disease. They’re used to treat serious, long-term conditions where biologics are the standard of care:
- Autoimmune diseases like rheumatoid arthritis, psoriasis, and Crohn’s disease
- Certain types of cancer, including breast cancer and lymphoma
- Diabetes (biosimilar insulins like Semglee)
- Chronic kidney disease
- Age-related macular degeneration (a leading cause of vision loss)
For many patients, biologics are life-changing. But they’re expensive - sometimes over $20,000 a year. Biosimilars often cost 15% to 30% less. That doesn’t just help patients pay less out of pocket. It also helps insurance systems cover more people.
What do biosimilars look like on a prescription?
Biologic drugs have two names: the brand name and the generic name. For example, Humira is the brand name for adalimumab.
A biosimilar of Humira might be called adalimumab-afzb. See that four-letter ending? That’s not random. It’s a unique suffix added by the FDA to tell the medicine apart - just like how different brands of aspirin all have the same active ingredient but different names.
When your doctor writes a prescription, they might write the generic name. But your pharmacy will know which version - brand or biosimilar - to give you. You’ll see the full name on the label. If you’re unsure, ask your pharmacist.
Will your insurance force you to use a biosimilar?
Some insurance plans prefer biosimilars because they’re cheaper. They might require you to try a biosimilar before covering the original biologic. This is called a "step therapy" rule.
It’s not about cutting corners. It’s about making sure life-saving treatments stay affordable for everyone. If you’ve been stable on your current biologic, your doctor can usually request an exception. You’re not stuck with a switch you don’t want.
Are biosimilars the same as "bioidentical" drugs?
No. This is a common confusion.
"Bioidentical" means the drug was made using the exact same process as the original - same cell line, same equipment, same steps. That’s rare. Most biosimilars are made with different cells or methods, but still end up working the same.
Think of it like two chefs making the same dish. One uses the same ingredients and stove as the original chef. The other uses different pots and a slightly different spice blend - but the taste? Identical. That’s a biosimilar.
What’s the future of biosimilars?
Biosimilars are growing fast. In the U.S., they make up about 10% of the biologics market. In Europe, it’s 25%. That gap is shrinking.
More biosimilars are coming - for cancer drugs like trastuzumab and bevacizumab, for insulin, and even for newer biologics used in multiple sclerosis and lupus.
There’s also something called an "interchangeable" biosimilar. That’s a special category. It means your pharmacist can switch you to it without asking your doctor first - just like swapping one generic pill for another. The first one approved was Semglee, an insulin for diabetes, in 2021.
Experts predict biosimilars could save the U.S. healthcare system over $50 billion over the next few years. That money can go toward helping more people get treatment.
What should you do if you’re offered a biosimilar?
Ask questions. That’s your right.
- Is this a biosimilar? What’s the brand name of the original drug?
- Has this been used by other patients? Is there data on how well it works?
- Will I notice any difference in how I feel?
- What if I switch back later?
Your doctor and pharmacist are your partners. They’ve seen these medicines work in real life. Don’t be afraid to talk about your concerns.
And remember: if you’ve been doing well on your current biologic, you don’t have to switch. But if you’re open to it, a biosimilar could mean lower costs without sacrificing safety or effectiveness.
Biosimilars aren’t a compromise. They’re a smart, science-backed way to keep advanced treatments within reach for more people.
Are biosimilars the same as generics?
No. Generics are exact chemical copies of small-molecule drugs like aspirin or metformin. Biosimilars are highly similar versions of complex biologic drugs made from living cells. They can’t be exact copies because biological molecules are too large and complex. But they work the same way and are just as safe.
Can I switch from my current biologic to a biosimilar safely?
Yes. Multiple studies, including ones reviewed by the FDA and the American Cancer Society, show that switching from a brand-name biologic to an approved biosimilar is safe and effective. Patients don’t lose control of their disease, and side effects remain the same. Many people switch without noticing any difference.
Why are biosimilars cheaper if they’re so complex to make?
They’re still expensive to produce - much more than generics. But because they don’t need to repeat all the early research done on the original drug, manufacturers save money on development. Those savings get passed on, usually lowering the price by 15-30%. That helps reduce costs for patients and insurers.
How do I know if I’m getting a biosimilar?
Check the prescription label. Biosimilars have the same generic name as the original biologic, but with a four-letter suffix - like adalimumab-afzb instead of just adalimumab. Your pharmacist will give you the exact name. If you’re unsure, ask them to confirm.
Do biosimilars have the same side effects as the original?
Yes. FDA approval requires proof that biosimilars have the same potential side effects as the reference product. If the original biologic can cause fatigue or increase infection risk, the biosimilar will too. These risks are well-documented and monitored even after approval.
Are biosimilars approved in other countries too?
Yes. The European Medicines Agency (EMA) approved its first biosimilar in 2006. Since then, over 100 biosimilars have been approved in Europe, Canada, Australia, Japan, and many other countries. The standards are just as strict as in the U.S. Patients in these regions have used them safely for nearly two decades.
What’s the difference between a biosimilar and an interchangeable biosimilar?
All interchangeable biosimilars are biosimilars, but not all biosimilars are interchangeable. An interchangeable biosimilar has been shown to produce the same clinical result as the original - and can be switched back and forth without increasing risk. Pharmacists can substitute it without asking your doctor. The first one approved in the U.S. was Semglee, an insulin for diabetes, in 2021.
What if I’m worried about trying something new?
It’s normal to feel that way. Medicine can feel overwhelming. But biosimilars aren’t new in the big picture. They’ve been used safely for over 15 years in Europe. In the U.S., they’ve been around since 2015. More than 30 are approved and available.
The FDA, CDC, American Cancer Society, and Arthritis Foundation all support them. They’re not a cost-cutting trick. They’re a way to make life-changing treatments more accessible.
If you’re on a biologic and doing well, you don’t need to switch. But if your doctor suggests a biosimilar - and you’re open to it - you’re not lowering your care. You’re choosing a proven, affordable option that works just as well.