2018 U.S. sales: $4.8 billion
Used for: rheumatoid arthritis, plaque psoriasis, psoriatic arthritis, ankylosing spondylitis and juvenile idiopathic arthritis
Amgen’s Enbrel continued its run as the second-best-selling immunology drug in the U.S., but there are troubling signs for its future near the top.
Enbrel secured $4.8 billion in U.S. sales in 2018, an 8% decrease from the year before, making it one of the few drugs in the year's top 20 to post a sales decline.
The problem isn't Enbrel biosimilars. In 2016, the FDA approved an Enbrel biosimilar from Sandoz, but the copycat has been locked in a court battle over Amgen’s patent privileges. If Amgen succeeds in federal court, it could secure Enbrel's exclusivity through 2029.
But Enbrel, similar to other immunology drugs, has faced competition stateside and abroad from biosimilars to other drugs in its class. Johnson & Johnson's Remicade, for instance, is under a barrage of biosimilar competition, including copycats from Pfizer and Merck & Co.
Amgen has also struggled to sustain Enbrel’s sales as aggressive payer discounting in the U.S. market has put the pinch on Enbrel's net pricing and reimbursement status. The company said formulary exclusions by payers have limited the drug's uptake in the competitive immunology market.