The FDA just approved another new drug that could save the US billions -- but there's a catch

The FDA just approved a version of Humira, the blockbuster arthritis drug made by AbbVie that brought in $14 billion in sales in 2015.

The drug, called Amjevita (adalimumab-atto), is a “biosimilar,” which is like a generic version of a biologic medication, a medicine produced by living cells.

Biosimilars are a bit more complicated than your average competing medicine: Unlike generics for chemical-based drugs like antibiotics, which can be interchangeable with branded versions, the copycats of biologic medications have a few more caveats.

“This is the fourth FDA-approved biosimilar. The biosimilar pathway is still a new frontier and one that we expect will enhance access to treatment for patients with serious medical conditions,” FDA director Janet Woodcock said in a news release.

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. 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.

But, because of patent litigation, Amjevita might not be available for years.

“We anticipated Amgen’s product would be approved,” an AbbVie spokeswoman said in a statement. “AbbVie and Amgen are currently in litigation over AbbVie’s Humira-related intellectual property.”

It’s the same thing that’s happening with other biosimilars: A biosimilar version of Enbrel is currently also tied up in a legal dispute.

What makes biosimilars different from generics

Developing a biosimilar is not as easy as creating a generic knockoff; because you’re working with complex living things, making a copy isn’t so simple.

“When you have a small molecule like Lipitor, you know where every single atom is,” Dennis Lanfear, CEO of biosimilar company Coherus Biosciences, told Business Insider in April.

That’s not the case with something like a monoclonal antibody — a type of lab-produced protein that can go after certain cells like your immune system would — which can vary widely. This means that you have to run the biosimilar through a bunch of studies to prove that it does the same thing that the original drug does, making development not only more complicated but much more expensive.

Coherus is developing biosimilar versions to drugs for autoimmune diseases and cancer treatment, including biosimilar versions of both Humira and Enbrel. It plans to file a biologic-licence application to the FDA for its version of pegfilgrastim, a bone marrow stimulant, in 2016.

“Biosimilars are here,” Lanfear said.

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