Sanofi and its vaccines business unit Sanofi Pasteur entered an agreement with MedImmune, the biologics R&D arm of AstraZeneca, to develop and commercialize monoclonal antibody MEDI8897 for the prevention of Respiratory Syncytial Virus (RSV) in infants. According to the CDC, RSV is the most common cause of lower respiratory tract infections in children younger than 1 year in the U.S. and worldwide. 

MEDI8897 is a highly potent monoclonal antibody (mAb) that neutralizes RSV by binding the RSV fusion (F) protein expressed on virions and infected cells; it has been engineered to have a long half-life so that only one dose would be needed for the entire RSV season. It is being developed for the passive immunization of the infant population. MEDI8897 is currently being investigated in a Phase IIb study in preterm infants with plans for a Phase III trial in healthy full-term infants. MEDI8897 received fast-track designation from the U.S. FDA in 2015.

Sanofi Pasteur will make an upfront payment of €120 million and pay as much as €495 million upon achievement of development and sales-related milestones. The two companies will share all costs and profits. MedImmune will continue to lead development up to the first approval, and AstraZeneca will retain MEDI8897 manufacturing activities. Sanofi-Pasteur will lead the commercialization activities.

“RSV is considered to be the most important missing indication in the vaccination schedule of newborns,” said David Loew, Sanofi executive vice president and head of Sanofi Pasteur. “As a global leader in the pediatric vaccine industry, this deal with MedImmune therefore makes perfect sense for Sanofi Pasteur. RSV causes major, seasonal worldwide outbreaks and the severity is predominant among young infants,” he continued. “We look forward to working with MedImmune to offer a solution to this common lower-respiratory disease when infants are most vulnerable.”