The Antibody Fragment Could Prevent and Treat Pneumonia in High-Risk Patients

Lyon, France | January 11, 2010 | Sanofi Pasteur, the vaccines division of the sanofi-aventis Group (EURONEXT : SAN and NYSE : SNY), announced today an agreement with KaloBios Pharmaceuticals, a U.S.-based, privately held biotech company, for the development of a Humaneered™ antibody fragment to both treat and prevent Pseudomonas aeruginosa (Pa) infections. Most serious Pa infections occur in hospitalized and critically or chronically ill patients– primarily affecting the respiratory system in susceptible individuals–and are a serious clinical problem due to their resistance to antibiotics.

Under the terms of the agreement, Sanofi Pasteur acquires worldwide rights to KaloBios’ technology for all disease indications related to Pa infections except cystic fibrosis and bronchiectasis, which Sanofi Pasteur has the option to obtain at a later date. KaloBios has already completed phase I clinical trials – one in healthy volunteers and one in cystic fibrosis patients – and a small proof of concept phase II clinical trial in mechanically ventilated patients.

“KaloBios has shown convincing safety data in phase I studies and a trend toward efficacy in a phase II study of ventilator-associated pneumonia,” declared Wayne Pisano, President and CEO of Sanofi Pasteur. “Hospital-acquired Pa infections are associated with very high levels of morbidity, mortality and costs and treating them represents a significant, unmet medical need. Despite modern antibiotic therapy, treatment failures, relapses and deaths are common,” said Pisano.

The two primary target indications for the antibody are prevention of Pa associated pneumonia in mechanically ventilated patients in hospitals as well as prevention of relapses and potential improvement of treatment outcomes in patients with an ongoing Pa infection. Additional indications – both prophylactic and therapeutic – can be considered later in the lifecycle of the product. This is the third announcement from Sanofi Pasteur in the last month on product development for nosocomial infections. On December 16 the vaccine manufacturer announced an agreement with Syntiron for the development, manufacture, and commercialization of a vaccine to prevent Staphylococcus infections, and on December 15 the company announced that its phase II vaccine trial to prevent Clostridium difficile – one of the most common causes of hospital-acquired infection in Europe and the United States – has expanded into the United States from the United Kingdom.

About sanofi-aventis

Sanofi-aventis, a leading global pharmaceutical company, discovers, develops and distributes therapeutic solutions to improve the lives of everyone. Sanofi-aventis is listed in Paris (EURONEXT: SAN) and in New York (NYSE: SNY). For more information, please visit: www.sanofi-aventis.com Sanofi Pasteur, the vaccines division of sanofi-aventis Group, provided more than 1.6 billion doses of vaccine in 2008, making it possible to immunize more than 500 million people across the globe. A world leader in the vaccine industry, Sanofi Pasteur offers the broadest range of vaccines protecting against 20 infectious diseases. The company’s heritage, to create vaccines that protect life, dates back more than a century. Sanofi Pasteur is the largest company entirely dedicated to vaccines. Every day, the company invests more than EUR 1 million in research and development. For more information, please visit: www.sanofipasteur.com or www.sanofipasteur.us

SOURCE: Sanofi-Pasteur