Pfizer Inc said on Thursday it would buy privately-held ReViral Ltd in a deal worth as much as $525 million, including milestone payments, to gain access to experimental drugs against the respiratory syncytial virus (RSV).

London-based Reviral has four RSV therapies in its pipeline, with two currently in mid-stage studies, including its lead product candidate sisunatovir.

The deal marks the U.S. drugmaker's second acquisition in less than six months to enhance its drug portfolio. Pfizer acquired Arena Pharmaceuticals in a deal worth $6.7 billion in December, adding a promising bowel disease treatment to its ranks.

RSV is a common respiratory virus that causes symptoms similar to those of a cold. It is a common cause of pneumonia in toddlers and the elderly.

According to analytics firm GlobalData, the RSV prevention market is expected to grow fourteen-fold to $6.3 bln by 2030 from 2020, making it a lucrative market for drugmakers globally.



(Reporting by Manas Mishra and Bhanvi Satija in Bengaluru; Editing by Aditya Soni and Devika Syamnath)