The U.S. Food and Drug Administration formally approved a competing biosimilar of Amgen’s top-selling drug Enbrel on Aug. 30.

Made by Switzerland-based Novartis, Erelzi mimics the effects of Enbrel. Enbrel, which was first approved in 1998, is approved to treat rheumatoid arthritis and other conditions by decreasing the amount of a protein produced by the immune system.

With sales of $5.3 billion last year, the drug made up about 20 percent of Amgen’s $21.6 billion in revenue. Enbrel sales also increased 10 percent during the second quarter of 2016 to $1.4 billion.

The FDA approval was seen as a formality after an FDA panel recommended Erelzi’s approval in July. It is part of a new class of drugs called biosimilars which are new, lower-cost treatments. They are similar to generics but made with living organisms and aren’t identical to the complex compounds they replicate.

Because the compounds are not identical, extensive testing must still take place to ensure their safety, which means they cost more than generics.

Still, biosimilars generally cost about 15 percent less than brand-name drugs, and are poised to take market share from them.

• Contact Philip Joens at pjoens@pacbiztimes.com.