Sanofi and its U.S. partner Regeneron said on Thursday the U.S.
Food and Drug Administration had designated their dupilumab drug as "breakthrough therapy" in the treatment of atopic dermatitis, a chronic form of eczema, granting the product a fast-track development and review process.
Dupilumab is also being studied in the treatment of revitol reviews asthma and chronic sinusitis with nasal polyps and is seen by both companies and financial analysts as a potential blockbuster.

It is one of the new medicines Sanofi will discuss at an investor day later on Thursday - an event likely to be overshadowed by uncertainties about the company's future after the summary dismissal of its chief executive last month. (Reporting by Natalie Huet; Editing by Biju Dwarakanath)