The medical marketplace is about to get bigger. The Food and Drug Administration (FDA) approved Zarxio (filgrastim-sndz), the first biosimilar product (or biosimilar), and expects to approve other biosimilars in the future.
What are biosimilars? To understand that, says Leah Christl, Ph.D., Associate Director for Therapeutic Biologics, it helps to first understand what biological products (or biologics), are.
Biologics are medicines that generally come from living organisms, which can include humans, animals and microorganisms such as yeast and bacteria.
Variable in Nature
“Biologics are different from conventional medications. Conventional medications—drugs—are generally made from chemicals, or chemically synthesized, and therefore their structure can be relatively easily defined,” explains Christl.
Unlike conventional medications, biologics can’t be made by following a chemical “recipe.” “Biologics come from living organisms which are variable in nature. In addition, they are generally more complex and not as easy to define and characterize, Christl explains. For that reason, manufacturing biologics is a far more complex process than manufacturing drugs.
Just as it does for drugs, FDA rigorously and thoroughly evaluates a biologic’s safety and effectiveness before granting it licensure (approval). Currently, biologics are among the fastest growing segments of the prescription product market.
What are Biosimilars?
Christl explains that a biosimilar is a type of biologic that is highly similar to another, already FDA-approved biologic (known as the reference product).
“It is important to note that a biosimilar is not just like a generic drug,” she adds. “Because of the differences in complexity of the structure of the biologic and the process used to make a biologic, biosimilars are not as easy to produce as generics, which are copies of brand name drugs. A biosimilar is not an exact duplicate of another biologic; rather, a biosimilar is highly similar to the reference product.
Before approving a biosimilar, FDA experts must also first verify that there are no clinically meaningful differences between the biosimilar and its reference product. In other words, it will work the same way as the reference product for its approved indications.
Also, the biosimilar must have the same strength and dosage form (injectable, for example) and route of administration as the reference product. The biosimilar must be manufactured following Current Good Manufacturing Practices.
“Patients can rest assured that they’ll be able to rely upon the safety and effectiveness of an FDA-approved biosimilar, just as they can rely on the reference product that the biosimilar was compared to,” Christl says. Like other biologics, biosimilars generally must be prescribed by a physician.
Zarxio, which is biosimilar to Neupogen, is a medication that boosts the production of white blood cells and helps to ward off infection in patients receiving strong chemotherapy for some tumors. The most common expected side effects of Zarxio are aching in the bones or muscles and redness, swelling or itching at injection site. Serious side effects include spleen rupture; serious allergic reactions and acute respiratory distress.
Increased Options, Lower Costs?
“Biosimilars are likely to create greater competition in the medical marketplace,” says Christl. This could not only increase treatment options for patients, but also lead to less expensive alternatives to comparable products. With an increasing number of biosimilars on the market, consumers may expect to get equally safe and effective treatment, but at lower costs, she says.
This article appears on FDA’s Consumer Updates page, which features the latest on all FDA-regulated products.
March 6, 2015