Amgen's Humira biosimilar clears Phase III and joins a crowd of contenders

Amgen's ($AMGN) knockoff of AbbVie's ($ABBV) top-selling Humira measured up to its reference product in a Phase III trial, clearing the way for the Big Biotech as it waits for the blockbuster injection to lose patent protection next year.

In a study on more than 500 patients with rheumatoid arthritis, Amgen's ABP 501 met its primary and secondary endpoints of improving symptoms at a rate similar to Humira with a comparable safety profile, the company said. Amgen said it's planning to submit its biosimilar for FDA approval by the end of the year.

Humira, approved for a range of autoimmune diseases, brought in about $12.5 billion for AbbVie last year, accounting for more than 60% of the drugmaker's total revenue. But the patents protecting Humira from biosimilar competition are set to expire at the end of 2016, and a growing number of would-be rivals are queuing up to compete.

Merck ($MRK), working with Samsung Bioepis, reported positive Phase III data for a Humira copy in July, plotting global regulatory filings in the coming months. And similar programs are underway from Novartis ($NVS) and partners Baxalta ($BXLT) and Momenta Pharmaceuticals ($MNTA), among others.

For Amgen, targeting Humira is in part an effort to dull the blow of biosimilar competition for its own medicines. Novartis' Sandoz business launched the U.S.'s first biosimilar this year with a take on Amgen's Neupogen, marketed as Zarxio. And a host of contenders are targeting Amgen's Humira rival, the blockbuster autoimmune treatment Enbrel, but the company believes it has secured patents that will protect that drug in the U.S. through 2029.

The gradual patent expirations for the world's top-selling biologics is expected to create a global biosimilar market worth more than $35 billion by 2020, analysts have said, driven by the loss of exclusivity for Johnson & Johnson's ($JNJ) Remicade, Roche's ($RHHBY) Herceptin and other aging blockbusters.

Outside of its take on Humira, Amgen is working with Allergan ($AGN) on biosimilars of Eli Lilly's ($LLY) Erbitux and Roche's Avastin, Herceptin and Rituxan. On its own, the company is developing a version of Remicade and three more as-yet-undisclosed programs.

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