European regulators took another step towards opening the market for copies of biotech drugs on by releasing a draft guideline on how companies should test biosimilar medicines containing interferon beta, used to treat multiple sclerosis. The guideline is open for consultation until the end of May 2012 and is part of a package of new regulations being prepared by the London-based agency.

Guido Rasi, the European Medicine Agency's new executive director, told Reuters on Jan. 6 the watchdog would issue its final guideline on biosimilar monoclonal antibodies - the biggest category of biotech medicines - in March or April.

Leading multiple sclerosis (MS) drugs containing interferon beta include Merck KGaA's Rebif and Biogen Idec's Avonex.

Under the guideline, companies wishing to copy such drugs would have to carry out a one-year clinical study and use magnetic resonance imaging (MRI) look at lesions in patients.

"Whatever the design, the duration of the trial should be sufficient to show comparable efficacy on MRI endpoints and provide relevant information on clinical outcomes, i.e. not less than 12 months," the guideline states.

Up to now, complex biotechnology medicines, which are given by injection, have been largely immune from generic competition, unlike conventional chemical pills and capsules. But the regulatory landscape is starting to change, posing a threat to leading biotech groups like Roche and Amgen, as well as makers of MS drugs and suppliers of insulin, such as Novo Nordisk.