About C. DifficileC. difficile is an anaerobic bacterium that is mediated by toxins, which can damage the lining of the gut causing severe symptoms such as diarrhea and cramping, and prevent normal, beneficial bacteria (flora) in the gut from growing back. An estimated 500,000 cases are diagnosed in the U.S. annually, resulting in more than20,000 deaths yearly. The infection most often occurs in people who have been hospitalized, although up to 28 percent of cases are community-acquired through contaminated soil, water, pets, cattle, and foods. Among people hospitalized, the incidence rate of the disease increases the longer a person stays in the hospital – from about 13 percent after a two-week stay to nearly 50 percent after four weeks. The infection has an estimated 10 to 60 percent chance of recurring, depending on the patient's risk factors such as age, bacterial strain, and re-growth of normal, healthy bacteria in the gut. Leadership in Infectious Diseases MedImmune's historical roots are in infectious disease. In 1998, it was the first company to launch a monoclonal antibody in the U.S. targeting an infectious disease (respiratory syncytial virus or RSV). The company also is recognized as a leader in vaccine development, introducing the first influenza vaccine innovation in more than 60 years – intranasal delivery in 2003. MedImmune introduced another first earlier this year, the world's first four-strain flu vaccine, approved by the FDA in February and available in the U.S. in 2013. MedImmune continues to explore how biologics can address the most hard-to-treat infectious diseases and help fulfill unmet needs among patients. Research is ongoing in such diverse areas as antibacterials, respiratory viruses and novel vaccines. About MedImmune MedImmune, the global biologics arm for AstraZeneca PLC, has approximately 3,500 employees worldwide and is headquartered in Gaithersburg, Maryland. For more information, visit MedImmune's website at www.medimmune.com. About Progenics Progenics Pharmaceuticals, Inc., of Tarrytown, N.Y., is a biopharmaceutical company dedicated to developing innovative medicines to treat disease, with a focus on cancer and related conditions. Progenics' pipeline candidates include PSMA ADC, a human monoclonal antibody-drug conjugate in phase 2 testing for treatment of prostate cancer, and preclinical stage novel phosphoinositide 3-kinase (PI3K) inhibitors for the treatment of cancer. Progenics has exclusively licensed development and commercialization rights for its opioid-induced constipation drug, Relistor, to Salix Pharmaceuticals, Ltd. for markets worldwide other than Japan, where Ono Pharmaceutical Co., Ltd. holds an exclusive license for the subcutaneous formulation. Relistor (methylnaltrexone bromide) subcutaneous injection is a first-in-class treatment for opioid-induced constipation approved in more than 50 countries for patients with advanced illness.