PARIS, March 21 (Reuters) - The effects of Sanofi's experimental multiple sclerosis drug Lemtrada continue to benefit the majority of patients long after they have completed their treatment, the French drugmaker said on Thursday.
In an extension trial sponsored by the company that followed up patients who had taken part in two late-stage studies, more than half did not experience any relapses in the first year after completing a two-course treatment with Lemtrada.
Multiple sclerosis is a chronic, often disabling disease that attacks the central nervous system and can lead to numbness, paralysis and loss of vision. It affects 2.5 million people worldwide and has no cure.
Lemtrada, which is given via an intravenous drip for five days and then for three days a year later, has the potential to re-programme the immune system and could potentially change the long-term progression of the disease.
"When you think about therapies to treat MS you think of therapies that are taken chronically, that when you stop them their effects are gone," Michael Panzara, therapeutic area head for MS and neurological research at Sanofi's rare disease unit Genzyme, told Reuters.
"What you have here is a change in the immune system and a prolonged effect."
The study showed that more than 80 percent of patients did not require a third course of Lemtrada in the first year after treatment, while more than 70 percent of patients showed improved or stable disability after three years.
"These findings are important because they suggest that the benefits of Lemtrada as observed in phase III studies are maintained, even though most patients did not receive further dosing," said Edward Fox, director of the Multiple Sclerosis Clinic of Central Texas, who presented the results at a medical congress in San Diego, California.
Lemtrada is under review by the European Medicines Agency and the U.S. Food and Drug Administration, which are expected to give their feedback by the end of 2013.
In addition to Lemtrada, Sanofi has developed MS pill Aubagio to boost growth after the patent loss on its ageing blockbusters and further its ambition to become a major player in this market.
Aubagio was launched in the U.S. in October, generating sales of 7 million euros ($9 million) in the last quarter of 2012.
The European Medicines Agency is due to give its verdict on the drug by the end of the month.
Shares in Sanofi, which have risen around 8 percent in the last month in the run-up to EMA's decision, closed at 77.32 euros on Thursday.
($1 = 0.7722 euros) (Reporting by Elena Berton; editing by Keiron Henderson)