Understanding Biosimilars: Better Access to Advanced Medicines

Understanding biologics

“Biologics are medicines made from living cells — think proteins like antibodies, hormones or enzymes,” explained Annie DePasquale, M.D., board-certified family medicine physician and founder at Collaborating Docs. “Traditional drugs (like most tablets) are small, chemically synthesized molecules that are identical batch to batch. Biologics are grown in living systems, so they’re naturally more variable and require extremely tight quality controls.”

Think of it this way: Each chemical is like a building block. Put a few blocks together in a certain way, and you get a small molecule drug. Anyone who has the same building blocks and puts them together in the same way can make an exact copy of the original. When this is done in the world of small molecule drugs, we get generic medicines. They’re exact copies of original, branded medications — just without the brand, which usually makes them less expensive.

Biologics are a lot more complicated. Instead of a simple structure made of a few dozen chemical building blocks, these macromolecules have thousands of pieces in a very complex arrangement. Making a biologic drug takes a lot more than clicking each piece into place. They’re organic compounds and have to be made in living cells, using DNA technology.

When you make a copy of a biologic to increase access to this therapy, you get a biosimilar, a therapy that is equally safe and effective to the therapy it copied. However, there are differences in structure. Think of it like baking bread. You can use the same ingredients and follow the same recipe, but each loaf of bread is a little bit different. The biosimilar copies of the biologic are not precisely identical to the originals, but they are very similar. Most importantly, they have the same safety and effectiveness.

From biologics to biosimilars

Generic medicines give us access to the same treatments at a lower cost. Biosimilars, like generics, make certain advanced treatments more affordable and accessible.

Biologics are very expensive. It might take over 10 years and cost billions of dollars to develop a single biologic. That cost gets passed on to patients and insurers. “Even after competition begins, biologics remain costlier to make than most pills, which is where biosimilars come in to help lower costs,” DePasquale said.

Biosimilars aren’t exactly cheap: They also take years to develop and still cost millions of dollars. But the total development cost is much less than an original biologic. So, they can be approved for use faster and with less expense. This cost reduction could help even out some disparities. People in historically marginalized groups, especially if they have public insurance, are less likely to fill their prescriptions for biologics. With more affordable biosimilars, more people can benefit from advanced medicines.

How biosimilars are made

Like biologics, biosimilars are made through a complex process using DNA technology.

First, the genetic code for a specific protein is inserted into living cells. These cells might be yeast, bacteria, plant or animal cells. The cells “read” the code like a recipe and then get to work producing large amounts of the protein. They’re like billions of tiny, organic kitchens. And they have high standards. The environment has to be strictly controlled so the conditions are right. Once the cells have created the protein, it is isolated and purified for use as a biosimilar medicine. These medicines can then be delivered to patients as injections or IV infusions.

Bioequivalent benefits

So, are biosimilars just as safe and effective as the original biologics? The answer is yes. “Biosimilars go through a rigorous FDA review using a ‘totality of evidence’ approach,” DePasquale said. “That includes analytical testing to show high similarity, studies of how the drug behaves in the body, immunogenicity assessments (risk of the body reacting to the protein) and at least one clinical study to confirm no meaningful differences.”

A biosimilar has to match the original biologic (called a reference product) very closely to be considered bioequivalent:

• It must be made with the same type of natural materials.
• It must match the reference product closely in molecular structure.
• It has to be just as safe to use.
• It has to provide the same treatment benefits.
• It has to have the same strength and dosage.
• It has to be administered in the same way.

The bottom line: Biosimilars have no clinically meaningful difference from the original reference product. They work the same way. They provide the same benefits. “In head-to-head comparisons, biosimilars perform equivalently to their reference products in the conditions they’re approved to treat,” said DePasquale. “Many patients have switched from a reference biologic to a biosimilar without any loss of effectiveness or new safety issues.”

What do biosimilars treat?

Biologics and biosimilars can treat “a wide range of conditions that [have a greater impact on] women or often arise in midlife,” explained DePasquale:

• Autoimmune diseases like rheumatoid arthritis, psoriatic arthritis, multiple sclerosis, lupus, inflammatory bowel disease, Crohn’s and plaque psoriasis.
• Cancer may be treated with biosimilars, including targeted therapies for specific cancers like HER2-positive breast cancer.
• Endocrine conditions like diabetes are often treated with biosimilar insulins.
• Some fertility treatments are biosimilars.

Biosimilars are advanced medicines, and they can mimic natural biological processes in the body. They target and bind to specific cells, interact with proteins, and block or trigger immune responses. So they’re very useful in preventing certain cells from doing the things that cause diseases to worsen or spread. With the lowered cost and increased access of biosimilars, more women can get the best possible treatment to live their best lives.