European regulators have adopted a new guideline on biosimilar antibody drugs this Friday. The EMEA briefly touched on the guidelines in a relese with title ‘Similar Biological Medicinal Products Containing Monoclonal Antibodies’. The guildline will be released for a five-month public consultation period.

“This guideline lays down the nonclinical and clinical requirements for monoclonal antibody-containing medicines claiming to be similar to another one already marketed,” EMEA explains.

The new rules are keenly awaited by drug companies and investors, who want to know what level of clinical testing will be required to win approval in Europe for copies of complex antibody-based drugs.

Previously many experts already anticipate a cautious approach by EU, requiring separate clinical trials for different diseases addressed by the same antibody, as Reuters notes.

Earlier this week, Lincoln Tsang, a partner at London law firm Arnold & Porter, told Reuters he expects the EMA to play it safe by requiring extensive testing. “My hunch is that they will be cautious in saying that if you can establish clinical efficacy and safety of a given product for a given indication you can’t readily seek approval for another indication,” he said. “Given it is such a big therapeutic area, I think they will not like to be seen to be too generous.”

As Reuters notes, such testing could drive up the costs of producing biosimilars, thus making it hard for smaller companies to enter the arena. If costs are too high, only well-established players like Teva, Novartis and Hospira might have the ability to bring such products to market.