Amgen's Humira biosimilar nears FDA nod, but legal hurdles remain

Amgen CEO Robert Bradway

Amgen's ($AMGN) take on AbbVie's ($ABBV) top-selling inflammation treatment is in line for FDA approval this year, but a patent fight between the two companies could keep it off the market into the next decade.

The FDA accepted Amgen's application for ABP 501, a biosimilar to AbbVie's Humira, and promised to hand down a final decision on the treatment by Sept. 25. In a study on more than 500 patients with rheumatoid arthritis, Amgen's treatment met its primary and secondary endpoints of improving symptoms at a rate similar to AbbVie's therapy with a comparable safety profile, and the company is hoping to win approval in each of Humira's cleared indications.

But ABP 501's eventual launch remains a cloudy proposition. Earlier this month, the U.S. Patent and Trademark Office declined to review a pair of AbbVie patents that Amgen contends are invalid, a blow to the company's plans to market its biosimilar by 2017. Amgen has promised to challenge those patents in court, but AbbVie believes its legal protection will keep Humira safe from competition until 2022.

Humira, approved for a range of autoimmune diseases, brings in about $12.5 billion for AbbVie each year, accounting for more than 60% of the drugmaker's total revenue and making it the biggest selling therapy in the world.

That has attracted a host of biosimilar developers hoping to cut in on AbbVie's cash cow. Behind Amgen is Merck ($MRK), working with Samsung Bioepis, plus Novartis ($NVS) and partners Baxalta ($BXLT) and Momenta Pharmaceuticals ($MNTA) among others.

Beyond its version of Humira, Amgen is working with Allergan ($AGN) on biosimilars of Eli Lilly's ($LLY) Erbitux and Roche's ($RHHBY) Avastin, Herceptin and Rituxan. On its own, the company is developing a version of ​Johnson & Johnson's ($JNJ) Remicade and three more undisclosed programs.

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