Europe's drugs watchdog is to evaluate a copycat version of the best-selling biotech drug Remicade, used to treat arthritis, in a move that underscores how the market for so-called biosimilars is opening up.

The European Medicines Agency's latest list of validated new drug applications includes one for a biosimilar version of infliximab, the generic name for Johnson & Johnson and Merck & Co's Remicade.

The London-based agency did not identify the company behind the application but analysts at Bernstein said they believed it was Celltrion, which has a European marketing deal with Hospira.

The brokerage said the odds of approval for the biosimilar form of Remicade were relatively high.

Up to now, complex biotechnology medicines, which are given by injection or infusion, have been largely immune from generic competition, unlike conventional pills. But the regulatory landscape is starting to change, posing a threat to makers of multibillion-dollar drugs for diseases like cancer and rheumatoid arthritis.

Europe has already approved some biosimilars, including copycat versions of human growth hormone and the anaemia treatment EPO, but it has yet to approve an antibody drug like infliximab.