Genzyme, a Sanofi company (EURONEXT: SAN and NYSE: SNY), announced it has received a Refuse to File letter from the U.S. Food and Drug Administration (FDA) in response to the supplemental Biologics License Application (sBLA) for the approval of LEMTRADA™ (alemtuzumab) as a treatment for relapsing multiple sclerosis. After collaborative consultations with the FDA, the agency requested that the company modify the presentation of the data sets to enable the agency to better navigate the application. The FDA has not requested additional data or further studies. Genzyme will work with the FDA over the coming weeks to resubmit the application as soon as possible. “We have had constructive dialogue with the FDA, and we are very confident in our ability to address the agency’s request and resubmit rapidly,” said David Meeker, President and CEO, Genzyme. The company’s marketing authorization application submitted to the European Medicines Agency has been accepted and the review process is underway. Genzyme is developing LEMTRADA in MS in collaboration with Bayer HealthCare. About Alemtuzumab/LEMTRADA™ Alemtuzumab is a monoclonal antibody that selectively targets CD52, a protein abundant on T and B cells. Treatment with alemtuzumab results in the depletion of circulating T and B cells thought to be responsible for the damaging inflammatory process in MS. Alemtuzumab has minimal impact on other immune cells. The acute anti-inflammatory effect of alemtuzumab is immediately followed by the onset of a distinctive pattern of T and B cell repopulation that continues over time, rebalancing the immune system in a way that potentially reduces MS disease activity. Genzyme holds the worldwide rights to alemtuzumab and has primary responsibility for its development and commercialization in multiple sclerosis. Bayer HealthCare retains an option to co-promote alemtuzumab in multiple sclerosis. Bayer HealthCare has notified Genzyme of its intention to co-promote under this option. Upon regulatory approval and commercialization, Bayer would receive contingent payments based on sales revenue.