Patients in some European countries with autoimmune diseases such as rheumatoid arthritis and Crohn's disease may soon have a cheaper treatment option, following today's statement from the European Medicines Agency recommending approval of two monoclonal antibody biosimilars to infliximab (Remicade).

The two agents, Remsima and Inflectra, have been shown to be equivalent to infliximab in safety and efficacy, and should be granted marketing approval by the European Commission, the statement noted.

Monoclonal antibodies and other biologic agents have revolutionized the treatment of autoimmune diseases, but carry a high price tag.

The manufacturer of Remsima, Celltrion, has said that its biosimilar will cost 30% less than the brand name version.

The biosimilars initially are likely to be marketed in a limited number of countries in Europe because of existing patent protection on Remicade, which extends until February 2015 in many countries and until 2018 in the U.S.

Infliximab and the biosimilars all target tumor necrosis factor-alpha, a cytokine central to the inflammatory response in these diseases.

Recently, a phase III study of the Celltrion biosimilar found that in more than 600 patients with active rheumatoid arthritis, American College of Rheumatology 20% improvement (ACR20) responses were seen in 60.9% of patients receiving the biosimilar for 30 weeks and in 58.6% of patients receiving infliximab.

Treatment-related adverse events also were similar, occurring in 35.2% and 35.9% of the biosimilar and infliximab groups, respectively (Ann Rheum Dis 2013; DOI: 10.1136/annrheumdis-2012-203090).

Other biosimilars are available in Europe, such as Nivestim, which is similar to the granulocyte colony-stimulating factor analog filgrastim, and product-specific guidelines for monoclonal antibodies have been established by the medicines agency.

According to the agency, any company seeking approval for a biosimilar must provide evidence that "it does not have any meaningful differences from the reference medicine in terms of its quality, safety, and efficacy."

But some experts have expressed concerns about unforeseen consequences, such as potential therapeutic variations from even slight structural differences. Another area of uncertainty could be the issue of pharmacy substitutions.