Why biosimilars aren’t just generics
Most people think if a drug is cheaper, it’s a generic. But when it comes to biologics, that’s not true. Biosimilars aren’t generics. They’re not copies. They’re not even close to the same thing. Generics are small-molecule drugs - simple chemical formulas you can replicate exactly. Biosimilars are complex proteins made from living cells. Think insulin, rheumatoid arthritis drugs, cancer treatments. These aren’t made in a lab with beakers and chemicals. They’re grown in bioreactors, like yeast or hamster cells. Even tiny changes in temperature, pH, or cell line can alter the final product. That’s why you can’t just copy them like you copy aspirin.
The FDA says a biosimilar must be highly similar to its reference biologic, with no clinically meaningful differences in safety, purity, or potency. That’s not a marketing slogan. It’s a legal standard backed by years of testing. But here’s the catch: providers still don’t get it. A 2021 survey of 102 U.S. doctors found only 38% felt extremely familiar with the FDA’s definition. That’s not a small gap. That’s a dangerous blind spot.
How biosimilars are proven to work
Generating a biosimilar isn’t a quick process. It takes years. First, manufacturers do hundreds of analytical tests - comparing the molecular structure, folding patterns, charge variants, and glycosylation profiles of the biosimilar and the original. Then they run non-clinical studies in animals. After that, they conduct one or two clinical trials in humans - usually comparing immune response, effectiveness, and safety head-to-head with the reference product. That’s a lot more than generics, which only need to prove bioequivalence through blood level tests.
Let’s say you’re using adalimumab (Humira) for psoriasis. A biosimilar like Amjevita doesn’t just claim to work the same. It has to show, in a controlled trial with hundreds of patients, that the rate of flare-ups, skin clearance, and side effects are statistically the same. And even then, it’s not just about the numbers. Immunogenicity - how likely the body is to react against the drug - must be monitored. Minor differences in inactive ingredients are allowed, but if those affect how the drug behaves in the body, it’s a red flag. That’s why you can’t assume all biosimilars are interchangeable.
Interchangeable vs. biosimilar: what’s the difference?
Not all biosimilars are created equal. Some are just biosimilars. Others are interchangeable. That’s a higher bar. An interchangeable biosimilar has been tested to prove that switching back and forth between it and the reference product doesn’t increase risk or reduce effectiveness. Think of it like this: a biosimilar is like a twin who looks and acts almost exactly like you. An interchangeable biosimilar is the twin who can swap places with you in any situation - even if you switch every day for months - and no one notices a difference.
The FDA has approved only a handful of interchangeable biosimilars so far. Most are insulin products, like Basaglar and Semglee. For other drugs, like infliximab or rituximab, even if they’re biosimilar, pharmacists can’t automatically substitute them unless the state allows it and the product has interchangeable status. That’s why provider education matters. If a doctor prescribes Humira, and the pharmacist tries to swap it for a non-interchangeable biosimilar without telling the patient or getting approval, it’s a violation. And patients get confused. A 2022 ArthritisPower survey found 34% of rheumatology patients felt unsure or anxious when switched to a biosimilar - not because it didn’t work, but because no one explained the change.
Why providers are hesitant - and how to fix it
Doctors, nurses, and pharmacists aren’t resisting change out of stubbornness. They’re unsure because the information is scattered, confusing, and often contradictory. A 2019 study comparing U.S. and European providers found U.S. professionals were 32% less familiar with biosimilar concepts. Why? Because in Europe, education was built into training programs. In the U.S., it’s left to hospitals to figure out.
Here’s what’s holding people back:
- Extrapolation: If a biosimilar is approved for one condition (say, rheumatoid arthritis), can it be used for another (like Crohn’s disease) without separate trials? The FDA says yes - if the science supports it. But 57% of providers still worry about this.
- EHR issues: Seventy-eight percent of U.S. hospitals say their electronic health records can’t properly track which version of a biologic a patient received. Epic and Cerner systems often lump biosimilars and reference products together. That means you can’t tell if a patient had a reaction to the original or the biosimilar. That’s a safety risk.
- Cost confusion: Some providers think biosimilars are cheap because they’re low quality. They’re not. They’re expensive to make - just less expensive than the original. Medicare Part B data shows biosimilars cost 28% less on average, but that savings doesn’t always reach patients because of how the supply chain works.
The fix? Education that’s practical, not theoretical. A 2017 study from Cancer Vanguard trained oncology staff over four months with 12 sessions. Before training, 40% of providers weren’t sure biosimilars would work as well. After? 92% felt confident. That’s not magic. That’s good teaching.
Who’s leading the way - and who’s falling behind
Adoption isn’t the same across specialties. Rheumatologists are at the front: 68% use biosimilars regularly. Oncologists are close behind at 52%. Why? Because they’ve seen the data. Clinical trials for biosimilars in cancer treatment are robust. The American College of Rheumatology’s 2021 guidelines gave a strong recommendation for biosimilar use in rheumatoid arthritis, based on 37 trials involving over 12,000 patients.
But endocrinologists? Only 29% use them. Even though insulin biosimilars have been available since 2015. Why? Because insulin is used by millions of patients with type 1 diabetes - many of them elderly or with limited health literacy. Providers fear switching could cause instability. And they’re right to be cautious. But that caution needs to be informed. A 2022 case study at UCSF Medical Center showed that when pharmacists led patient education sessions - explaining the science, addressing fears, and documenting the switch - hesitancy dropped from 58% to 12% in six months.
Community pharmacists are also lagging. A 2021 survey found hospital pharmacists scored 27% higher on biosimilar knowledge than community pharmacists. That’s a problem. Community pharmacists are the last line of defense. If they don’t know the difference between interchangeable and non-interchangeable, they might substitute without authorization - or worse, refuse to substitute when they should.
What you need to know to get it right
If you’re a provider, here’s what you need to focus on:
- Know the difference between biosimilar and interchangeable. Check the FDA’s Purple Book. It lists which products are interchangeable. Don’t guess.
- Understand extrapolation. Just because a biosimilar was tested in one disease doesn’t mean it’s unsafe in another. The science behind extrapolation is solid - but you need to know why.
- Check your EHR. Can you tell which version of the drug was given? If not, push for system updates. Document every switch.
- Communicate with patients. Don’t just say, “We’re switching you.” Explain: “This is a different version of the same medicine. It’s been tested just as carefully. It’s cheaper, and it works the same.”
- Use trusted resources. The FDA’s Teaching Resource Guide has 12 free modules - covering everything from manufacturing to billing. No need to rely on pharma reps. Use the official materials.
And if you’re not sure? Ask. Talk to your clinical pharmacist. Attend a webinar. The FDA, the Arthritis Foundation, and the American Pharmacists Association all offer free, evidence-based training. You don’t need to be an expert overnight. But you do need to start.
The future is here - and it’s waiting for you
By 2027, biosimilars could make up 45% of the biologics market. That’s $150 billion in potential savings over the next decade. But none of that matters if providers don’t understand what they’re prescribing. The technology is ready. The data is solid. The savings are real.
The only thing holding us back is knowledge. And knowledge can be taught.
Are biosimilars safe?
Yes. Biosimilars undergo more testing than generics. They must prove they’re highly similar to the original biologic in structure, function, and clinical effect. The FDA requires extensive analytical, non-clinical, and clinical studies to confirm safety, purity, and potency. No clinically meaningful differences have been found in approved biosimilars.
Can biosimilars be substituted without a doctor’s approval?
Only if the biosimilar has FDA interchangeable status AND your state allows automatic substitution. As of 2023, 42 U.S. states have laws permitting substitution, but rules vary. Some require the prescriber to be notified immediately, others allow a 7-day window, and six states have no requirement. Always check your state’s law and the product’s status in the FDA’s Purple Book.
Why are biosimilars cheaper if they’re so complex to make?
They’re not cheap to make - but they’re cheaper than the original. Biosimilars don’t require the same costly clinical trials as the original biologic, because they rely on the reference product’s safety data. Manufacturers save on R&D and marketing, and competition drives prices down. In Europe, biosimilars cut costs by 30-80% for some drugs. In the U.S., Medicare Part B data shows 28% lower average prices.
Do biosimilars work the same for all conditions the original drug treats?
Yes - if the FDA approves extrapolation. A biosimilar approved for rheumatoid arthritis can also be used for Crohn’s disease or psoriasis, even if it wasn’t tested in those conditions, as long as the mechanism of action and target are the same. The FDA requires strong scientific justification, and multiple studies support this approach. But provider confusion remains, so clear communication with patients is essential.
Why is EHR documentation a problem with biosimilars?
Many EHR systems don’t distinguish between biosimilars and reference biologics. They’re often coded the same way, making it impossible to track which version a patient received. This creates risks for safety monitoring, adverse event reporting, and insurance billing. Hospitals that have updated their systems to use specific product codes report fewer errors and better patient outcomes.
Next steps for providers
Start with the FDA’s Teaching Resource Guide. It’s free, peer-reviewed, and updated regularly. Take 2 hours this week to go through the first module on biosimilar basics. Then talk to your pharmacy team. Ask: “Do we know which biosimilars we’re using? Can our system track them?” If not, push for change. Patient safety and cost savings depend on it. You don’t need to be an expert tomorrow. But you do need to begin today.
