The FDA just approved the first direct competitor to a billion-dollar cancer drug

As it stands right now, biosimilars can't be used interchangeably with branded versions, meaning if you were to get a prescription for a branded biologic, you wouldn't be able to opt for the "generic" one at the pharmacy as easily as you could if the drug was, say, a statin.

The FDA just approved a version of Avastin, a blockbuster chemotherapy made by Genentech that brought in $6.7 billion in sales in 2016. The newly approved drug, made by Amgen, will go by the marketed name Mvasi. It's a type of medication called a "biosimilar."

Biosimilars are a bit more complicated than your average competing medicine: Unlike generics for chemical-based drugs like antibiotics that can be interchangeable with branded versions, the copycats of biologic medications, produced using living cells, have a few more caveats. The FDA has approved a number of these drugs.

As it stands right now, biosimilars can't be used interchangeably with branded versions, meaning if you were to get a prescription for a branded biologic, you wouldn't be able to opt for the "generic" one at the pharmacy as easily as you could if the drug was, say, a statin.

Having more biosimilars in the US would be a big deal: It might be the best way to drive down the cost of biologic medications that have been around for a while.

"Bringing new biosimilars to patients, especially for diseases where the cost of existing treatments can be high, is an important way to help spur competition that can lower healthcare costs and increase access to important therapies," FDA commissioner Scott Gottlieb said in a news release.

The savings of putting people on far less costly biosimilars — even just new patients who have never taken the original — are estimated to be billions of dollars. Express Scripts, a pharmacy benefit manager, estimated in 2013 that the US could be saving $250 billion over the next 10 years because of biosimilars. Some argue that the response to biosimilars entering the market has been disappointing so far, though.

picture REUTERS/Karoly Arvai