There was good news for French drug giant Sanofi this week as data from an extension study backed the long-term efficacy of its multiple sclerosis drug Lemtrada.

Interim data from the first 12 months of the extension trial showed that relapse rates and sustained accumulation of disability were low among patients previously treated with Lemtrada (alemtuzumab) in either of the two-year Phase III CARE-MS I or CARE-MS II studies. 

In both these Phase III trials, Lemtrada was was given as an IV administration on five consecutive days, and the second course was administered on three days 12 months later. 

After the first year of the extension arm, more than 80% of patients did not need further treatment with the drug, and more than half remained relapse-free through the first year of the extension study, the drugmaker said. 

Unique approach

The data "really speaks to Lemtrada’s unique approach to disease modification, where you have this rebalancing of the immune system after these two courses of treatment,” Genzyme's Michael Panzara told Bloomberg.

Lemtrada is an injectable monoclonal antibody - already licensed to treat leukaemia under the brand name Campath - which came to Sanofi via its $20 billion purchase of US biotech Genzyme back in 2011. 

Genzyme has filed applications to market Lemtrada on both sides of the Atlantic, and is expecting decisions from the European Medicines Agency and the US Food and Drug Administration later this year.

If approved, the drug will join Aubagio (teriflunomide) in Sanofi's fresh MS franchise; the latter was given a green light in the US as a once-daily, oral treatment for patients with relapsing forms of MS in September last year.