When your doctor prescribes a biologic drug for arthritis, Crohn’s disease, or cancer, you might hear about a biosimilar as a possible option. But what does that even mean? Is it the same as a generic? Is it safe? Will it work just as well? These are normal questions-and the answers are simpler than you think.
What exactly is a biosimilar?
A biosimilar is a medicine that works almost exactly like an already-approved biologic drug. It’s not a copy, but it’s as close as science can get without being identical. Think of it like two different brands of running shoes. They might look slightly different, use different materials in the sole, or have a different color, but they both give you the same support, comfort, and performance on the track. Biologic drugs are made from living cells-like yeast, bacteria, or animal cells-engineered to produce proteins that treat serious conditions. These proteins are huge, complex molecules, sometimes made of thousands of atoms arranged in intricate shapes. Because they come from living systems, no two batches are ever 100% identical, even when made by the same company. That’s why a biosimilar doesn’t need to be an exact copy. It just needs to work the same way in your body. The U.S. Food and Drug Administration (FDA) requires biosimilars to go through over 100 tests to prove they match the original biologic in structure, how they behave in the body, and how safe they are. Only after passing all these tests can a biosimilar be approved.Biosimilars vs. generics: What’s the difference?
This is where people get confused. Generics and biosimilars both save money, but they’re not the same thing. A generic drug, like ibuprofen or metformin, is a chemical copy of a small-molecule drug. These are made in labs using simple chemical reactions. If the original pill has 200 milligrams of ibuprofen, the generic has exactly the same molecule, in the same amount, with the same effects. Biosimilars are different. They’re made from living cells, not chemicals. Because of that complexity, scientists can’t make an exact duplicate. Instead, they make a version that’s “highly similar.” The FDA says there must be no clinically meaningful differences in safety, strength, how it works, or side effects. Here’s a quick comparison:| Feature | Generic Drug | Biosimilar |
|---|---|---|
| What it copies | Small-molecule chemical drug | Large, complex biologic drug |
| Exact copy? | Yes, molecule-for-molecule | No, but highly similar |
| How it’s made | Chemical synthesis in a lab | Living cells (like yeast or bacteria) |
| Testing required | Basic bioequivalence tests | 100+ analytical, animal, and clinical studies |
| Example | Metformin (generic for Glucophage) | Infliximab-dyyb (biosimilar for Remicade) |
Are biosimilars safe?
Yes. Every FDA-approved biosimilar has been tested in thousands of patients. For example, the biosimilar Renflexis, used for rheumatoid arthritis, was studied in 541 people before approval. In Europe, where biosimilars have been used for over 15 years, millions of patients have taken them with no new safety concerns. The FDA doesn’t approve biosimilars unless they work just as well as the original-and don’t cause more side effects. In fact, many patients who switch from the original biologic to a biosimilar see no change in how they feel. Studies show that switching is safe and effective, even for people with long-term conditions like psoriasis or Crohn’s disease. You might wonder: “If it’s not identical, could it react differently in my body?” The answer is: possible, but extremely rare. The body’s immune system might react slightly differently to tiny variations in the molecule, but these differences are monitored closely. That’s why every biosimilar has a unique name with a four-letter suffix at the end-like adalimumab-atto for Humira. This helps doctors and pharmacists track exactly which version you’re taking if something happens.
Why do biosimilars cost less?
Developing a biologic drug can cost over $1 billion and take more than a decade. Biosimilar makers don’t have to start from scratch. They use the original drug’s data to prove similarity, which cuts down on research costs. That’s why biosimilars are typically 15% to 30% cheaper than the brand-name version. This isn’t just about savings for insurance companies. It’s about access. Many patients can’t afford biologics that cost $20,000 a year. A biosimilar might bring that down to $14,000-making treatment possible where it wasn’t before. Some insurance plans now require you to try a biosimilar first before covering the original biologic. This isn’t because the biosimilar is “lesser”-it’s because it’s just as effective and saves money. You can always talk to your doctor if you’re worried about switching.What conditions are treated with biosimilars?
Biosimilars are used for serious, long-term conditions where biologics are the standard treatment:- Rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis
- Crohn’s disease and ulcerative colitis
- Plaque psoriasis and other skin conditions
- Non-Hodgkin’s lymphoma, breast cancer, and colorectal cancer
- Diabetes (biosimilar insulins like Semglee)
- Macular degeneration (eye disease)
- Chronic kidney disease
What should you do as a patient?
If your doctor suggests a biosimilar, here’s what to ask:- Is this biosimilar approved for my exact condition?
- Has it been studied in people like me?
- Will my insurance cover it?
- Can I switch from the original drug safely?
What’s next for biosimilars?
The future looks bright. The global biosimilar market is expected to grow from $7.3 billion in 2022 to over $30 billion by 2028. That means more choices, lower prices, and better access. There’s also a new category called “interchangeable” biosimilars. These are biosimilars that pharmacists can swap for the original drug without asking your doctor first-just like generics. The first one, Semglee (an insulin for diabetes), was approved in 2021. More are on the way. The goal isn’t to replace biologics-it’s to make them available to more people. And for patients, that means more hope, less financial stress, and treatments that work just as well.Are biosimilars experimental?
No. Biosimilars are not experimental. They go through the same strict testing as brand-name biologics before approval. Millions of patients worldwide have used them safely for over 15 years. The FDA requires proof they work just as well and are just as safe.
Can I switch from my current biologic to a biosimilar?
Yes, in most cases. Studies show that switching from a brand-name biologic to a biosimilar is safe and doesn’t affect how well the medicine works. Many patients switch without noticing any difference. Always talk to your doctor first, but don’t assume switching is risky-it’s a common and well-studied practice.
Why do biosimilars have weird names with extra letters?
The extra four letters (like “-dyyb” or “-atto”) are added to help track which exact product you’re using. This is important for safety-if a side effect happens, doctors and regulators can tell if it came from the original drug or the biosimilar. It doesn’t mean the medicine is different-it’s just for monitoring.
Do biosimilars cause more side effects?
No. FDA-approved biosimilars have the same side effect profile as the original biologic. In clinical trials and real-world use, rates of side effects like infections, rashes, or fatigue are nearly identical. The FDA continues to monitor all biosimilars after approval to catch any rare issues.
Why aren’t biosimilars cheaper like generics?
Because they’re harder to make. Biologics come from living cells, which require complex, expensive processes to grow, purify, and stabilize. A biosimilar still needs advanced labs, skilled workers, and strict quality controls-so while they’re cheaper than the original, they’re not as cheap as a simple chemical pill.