Sanofi has been boosted by the news that the US Food and Drug Administration has accepted its file for its multiple sclerosis drug Lemtrada, having turned down an application last year.

In August, the FDA told Sanofi's Genzyme unit that it needed to "modify the presentation of the data sets to enable the agency to better navigate the application". However, it did not request additional data or further studies for Lemtrada (alemtuzumab), and the company has made the requested changes.

Genzyme says it expects FDA action on the application in the second half of 2013 and it also hopes to have heard from the European Medicines Agency by then, as the latter's review process is underway. Genzyme president David Meeker said the acceptance of the Lemtrada file in the USA "marks another important milestone in bringing this potentially transformative therapy to MS patients".

Last summer, Sanofi started pulling an already-approved different-dose form of alemtuzumab, Campath/MabCampath for B-cell chronic lymphocytic leukaemia, from markets on both sides of the Atlantic in order to concentrate on the compound in MS.

Strong Aubagio launch in USA

Sanofi then went on to report "very encouraging early launch indicators" for its MS pill Aubagio (teriflunomide). Since its launch in the USA in October, more than 80% of MS specialists in the country have prescribed once-daily, oral treatment, and one in five patients on Aubagio were treatment-naive.

Furthermore, more than 50% of Aubagio patients were most recently on Teva's Copaxone (glatiramer acetate) and Biogen Idec's Avonex (interferon beta-1a), both blockbuster injectables. Dr Meeker added that "the initial uptake of Aubagio by US prescribers shows the importance of a once-daily oral option in MS”.

The drug is going up against Novartis' MS pill Gilenya (fingolimod) and the FDA is also expected to approve Biogen Idec's BG-12 (dimethyl fumarate) soon.