Sanofi (SNY) shares were up more than 1% Tuesday after the drugmaker said that Beyfortus for respiratory syncytial virus prevention in infants met both of its primary endpoints in its largest US real-world study.

The study showed that babies administered with Beyfortus were 87% less likely to develop RSV disease compared with babies who did not receive an injection of the antibody, the company said.

The study also showed that if babies who received Beyfortus later tested positive for RSV, they saw fewer overall medical visits during the illness, Sanofi said.

Beyfortus was developed in partnership with AstraZeneca (AZN). RSV is a contagious virus that can lead to respiratory illness, Sanofi said.

Price: 48.60, Change: +0.67, Percent Change: +1.40