South Korean biopharmaceutical manufacturer Celltrion has announced that it has filed an application for approval with the US Food and Drug Administration (FDA) for Remsima, its biosimilar version of Jannsen's Remicade (infliximab).

The company's biosimilar filing is the second-ever filing of a drug through FDA's new 351(k) biosimilar pathway, and reportedly the first-ever monoclonal antibody (mAb) to seek approval through the pathway.

The first biosimilar filing for approval was submitted on 24 July 2014 by Sandoz, which is seeking approval for Zarzio, a biosimilar version of Neupogen (filgrastim).

Regulatory Challenges Ahead

Like Sandoz's Zarzio, Celltrion's Remsima will have to overcome many difficult regulatory challenges prior to obtaining FDA's stamp of approval, including how "similar" FDA will find Remsima to Remicade.

FDA has explained that it plans to hold biosimilar products to a four-part standard for biosimilarity:

• not similar
• similar
• highly similar
• highly similar with a fingerprint-like similarity

But aside from explaining that the standard would be used by regulators, FDA has so far offered little in the way of details about how drugs might find themselves in each of the four categories.

Zarzio and Remsima are also likely to be the first drugs to be subject to FDA's unreleased biosimilar naming guidance, which will determine what the drugs' nonproprietary names should be, and fights over whether the drugs are similar enough to be interchangeable with the reference biologic on which their approval is based.

Prospects for Approval

Like Sandoz, Celltrion isn't seeking approval for an untested product. Remsima, like Zarzio, has obtained approval in several dozen countries and regions, including in Canada, Japan and the EU. Celltrion said the product is the only biosimilar monoclonal antibody to be approved simultaneously in all three regions.

Celltrion said it anticipates receiving FDA approval for Remsima within 12 months, though it cautioned that a patent on the drug owned by Janssen expires in 2018. It is challenging all remaining patents in court—a process which could slow approval.

Celltrion Announcement