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FDA Approves First Biosimilar Drug, But What’s A Biosimilar?


Written By: Christina Johnson

This spring the Food and Drug Administration approved the first biosimilar drug for use in the United States, opening the regulatory door to lower-cost versions of a class of pharmaceuticals called biologics. The drug, Zarzio, helps patients receiving chemotherapy make white blood cells, preventing infections common among cancer patients. It is considered therapeutically equivalent to the existing biologic, Neupogen.

blue and green pills

But what exactly are biologics and biosimilars?

We should all be curious because about one-third of new drugs approved in the last decade were biologics, according to PhRMA. Many of the most expensive drugs – particularly cancer drugs – in the United States are biologics, too.

“The term biologics has been around for more than 20 years,” said Chuck Daniels, PhD, pharmacist-in-chief for UC San Diego Health, and professor of clinical pharmacy and associate dean at Skaggs School of Pharmacy and Pharmaceutical Sciences at University of California, San Diego. “But more people are talking about them because most of the new high-cost agents fall into the biologics category.”

Take for example the melanoma treatment Yervoy (ipilimumab), approved by the FDA in 2011. It costs about $30,000 per injection, translating to about $120,000 for one course of therapy.

Other popular biologics include vaccines, human growth hormones, the cancer treatments Avastin and Herceptin, and some new injectable drugs for rheumatoid arthritis and other autoimmune diseases (such as Remicade and Enbrel). Botox, the neurotoxin protein widely used in cosmetic treatments is also a biologic, produced by Clostridium botulinum bacteria and related species.

A biologic, Daniels explained, is a catch-all terms for products that are made and extracted from living cells, animal or microbial. Traditional drugs, in contrast, are chemically synthesized.

Biologics tend to be larger, more complex compounds than traditional drugs, often proteins or peptides (protein fragments). The biggest difference is the ease with which biologics can be mimicked. While it is possible to manufacture an identical copy of an original trademarked traditional drug, a similar replication process is not yet possible with biologics.

As a result, the FDA recognizes biosimilars as biologic’s version of a generic drug: biologic drugs that are similar but not identical to the original biologic.

To meet the biosimilar regulatory criteria, a biosimilar must have the same route of administration, dosage and strength as the original product. “Biosimilars are intended to create the same result in humans, even if they are not exactly the same chemically as the original drug,” Daniels said. “In contrast, generic drugs are the exact chemical duplicates of the original brand product, expected to have identical results.”

“Biosimilars have been available in Europe for a few years,” he said. “The hope is that they will bring down the prices for consumers. How much is an unknown, but if the international experience holds for the U.S., biosimiliars could lower prices by at least 25 percent.”

Consumers have a vested interest in lower cost therapeutic agents, as many new biologics are in the drug pipeline. “If many of them get FDA approval, there will be a continuing trend toward biologic agents for several years,” Daniels said. “The benefit to consumers is the potential for some life-saving new drugs, if they can afford the high-prices which are likely to come along with them.”

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