Genzyme to Present New Data from AUBAGIO® and LEMTRADATM Clinical Development Programs at ECTRIMS

Jean-Marc Podvin, +33 (0) 1 53 77 46 46orErin Walsh, +1 617-768-6881Mobile: +1 617-945-3628orSébastien Martel, +33 (0) 1 53 77 45 45orKristen Galfetti, +1 908-981-5560

, a Sanofi company (EURONEXT: SAN and NYSE: SNY),announced today new data from Genzyme’s clinical development programs for AUBAGIO (teriflunomide) and LEMTRADA (alemtuzumab) will be presented at the 28 Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) in Lyon, France, October 10-13.

said Genzyme CEO and President, David Meeker.

Once-daily, oral AUBAGIO is now commercially available in the U.S. following FDA approval in patients with relapsing forms of MS. Marketing applications for AUBAGIO and LEMTRADA are currently under review by the EMA and other regulatory authorities.

Key data from across the company’s clinical development programs to be presented are as follows. Abstracts are available on the ECTRIMS website.

(eriflunomide ral in people ith relapsing multipl scleosis)

TOWER is a randomized Phase III trial assessing once-daily oral AUBAGIO (teriflunomide) in patients with relapsing multiple sclerosis. It is the second Phase III study for AUBAGIO.

(omparison of lemtuzumab and ebif fficacy in ultiple clerosis )

CARE-MS II was a randomized Phase III clinical trial designed to evaluate whether the investigational MS therapy LEMTRADA (alemtuzumab) could achieve meaningful efficacy and safety improvements over the approved, active comparator Rebif (subcutaneous interferon beta-1a 44 mcg).

Additional Genzyme MS portfolio data, in addition to the Genzyme satellite symposia to be featured at ECTRIMS include:

Thursday, October 11;12:45 – 1:45 p.m. CEST

Amphitheatre

The U.S. Food and Drug Administration (FDA) has approved AUBAGIO® (teriflunomide) as a once-daily, oral immunomodulator indicated for patients with relapsing forms of multiple sclerosis (MS). The ongoing AUBAGIO clinical development program, involving more than 5,000 patients in 36 countries, is among the largest of any MS therapy. Some patients in extension trials have been treated up to 10 years.

AUBAGIO is an immunomodulator with anti-inflammatory properties. Although the exact mechanism of action for AUBAGIO is not fully understood, it may involve a reduction in the number of activated lymphocytes in the central nervous system (CNS).

Click for full Prescribing Information for once-daily oral AUBAGIO (teriflunomide).

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.

LEMTRADA™ is the proprietary name submitted to health authorities for the company’s investigational multiple sclerosis agent alemtuzumab.

Genzyme has pioneered the development and delivery of transformative therapies for patients affected by rare and debilitating diseases for over 30 years. We accomplish our goals through world-class research and with the compassion and commitment of our employees. With a focus on rare diseases and multiple sclerosis, we are dedicated to making a positive impact on the lives of the patients and families we serve. That goal guides and inspires us every day. Genzyme’s portfolio of transformative therapies, which are marketed in countries around the world, represents groundbreaking and life-saving advances in medicine. As a Sanofi company, Genzyme benefits from the reach and resources of one of the world’s largest pharmaceutical companies, with a shared commitment to improving the lives of patients. Learn more at .

Sanofi, a global and diversified healthcare leader, discovers, develops and distributes therapeutic solutions focused on patients’ needs. Sanofi has core strengths in the field of healthcare with seven growth platforms: diabetes solutions, human vaccines, innovative drugs, consumer healthcare, emerging markets, animal health and the new Genzyme. Sanofi is listed in Paris (EURONEXT: SAN) and in New York (NYSE: SNY).

Genzyme is a registered trademark. All rights reserved.

AUBAGIO is a registered trademark. All rights reserved.

Rebifis a registered trademark of EMD Serono, Inc. or affiliates.