Sanofi to appeal Lemtrada rejection

Sanofi has confirmed its Genzyme unit is set to launch an appeal against the decision by the US Food and Drug Administration (FDA) to reject its Lemtrada multiple sclerosis treatment.

In response to the agency's Complete Response Letter – in which it stated the company has failed to submit sufficient evidence to assert the benefits of the drug outweigh its adverse side effects – Genzyme said it "strongly disagrees" with the FDA's stance.

It is estimated that failure to market the drug will significantly impact upon the firm's sales forecasts, which were previously estimated to reach $700 million (422 million pounds) by 2018.

The FDA said that to be granted permission to trade Lemtrada – which also goes by the scientific name of alemtuzumab – Genzyme must conduct further active comparator studies.

However, the company's president and chief executive David Meeker said the existing clinical trial results "provide robust evidence of efficacy and a favourable benefit-risk profile".