South Korea’s Celltrion has submitted its biosimilar of Johnson & Johnson and Merck & Co's anti-inflammatory blockbuster Remicade to regulators in the USA.

The filing of Remsima, Celltrion’s version of Remicade (infliximab) is the first for a monoclonal antibody using the Food and Drug Administration’s new biosimilar pathway. Last month, the agency accepted the first actual biosimilar for review, Novartis unit Sandoz’s Zarzio, a version of Amgen’s Neupogen (filgrastim) for patients with low white blood cell counts.

Celltrion said that after prior consultation with the FDA, it conducted additional clinical trials (starting on October 2013 and lasting six months) “to determine the bioequivalency of the originator products with Remsima”. The firm added that “barring any setbacks”, it expects US approval within a year.

The patents on Remicade are set to expire at the end of 2018  but Celltrion has filed a lawsuit in Massachusetts, claiming they are invalid and unenforceable. A Celltrion official said the filing with the FDA “is garnering interest not only from other biosimilar developers, but from healthcare providers and the healthcare industry as a whole”.

Remsima is already approved in Europe, Canada and Japan.