What is a biosimilar, you ask? No, it’s not your long lost twin or doppelgänger, but a new kind of drug that acts like the biological drugs we are already familiar with like Humira or Enbrel. And last week Zarxio (a biosimilar alternative to white blood cell boosting Neupogen), became the first one to be approved by the Food & Drug Administration (FDA) in the United States.

Biological drugs are complex because they are made from living organisms and have an intricate structure- they are not as easy to replicate and cannot be altered as easily as synthetic chemical drugs. They don’t see much competition from generics because they are so tedious to produce and difficult to copy, and many of their patents are still valid. They are usually classified as specialty drugs, which we know are pretty expensive and continue to grow in price.

Biosimilar products may be a cost effective alternative to pricey big label prescription drugs. In countries where they are already widely used they are often sold at a cheaper price (20%-30% cheaper) than the brand name drug. Generic drugs are sometimes 80% cheaper, but since generic drugs are so difficult to make off of biological drugs, maybe biosimilars will be the answer. They are not a match to the brand name drugs like generics are, but they are not meaningfully clinically different and have the same potency as the original.

However, just because the FDA approved this drug does not mean it can be prescribed right away. They still have to make sure it can be used interchangeably with the brand name drugs and be expected to produce the same results. The FDA has yet to really provide clear guidelines on what can determine interchangeability. Right now, if a patient wants the drug they need to get approval from their doctor and the doctor needs to specifically request the biosimilar by name from the pharmacy. An interchangeable biological drug can be substituted by the pharmacist just like generic, without the explicit permission of the doctor. As of now, it seems that other biosimilar drugs are in the works and we might see them become a big part of the drug industry pretty soon.