PfizerPfizer (NYSE:PFE) announced today that it entered into an agreement to acquire biopharmaceutical company ReViral.

ReViral discovers, develops and commercializes novel antiviral therapeutics designed to target respiratory syncytial virus (RSV).

“At Pfizer, we have a strong heritage in, and commitment to, fighting infectious diseases, most recently evidenced by our delivery of the first authorized vaccine and oral therapy to combat COVID-19,” Pfizer Chairperson and CEO Albert Bourla said in a news release. “We’re continuing to grow our pipeline – through our own research-and-development efforts, such as our investigational RSV vaccine programs, as well as strategic investments in companies like ReViral – with a focus on end-to-end capabilities to help protect patients from severe illness, hospitalization, and death.”

ReViral’s portfolio includes the sisunatovir oral inhibitor for blocking the fusion of the RSV virus to the host cell. Sisunatovir has fast track designation from the FDA.

The therapeutic proved successful in significantly reducing viral load in a phase 2 RSV human challenge study in healthy adults, while the company currently has a phase 2 clinical development in infants underway. The company also has a second program focused on the inhibition of RSV replication, targeting the viral N protein, in phase 1 clinical development.

Under the agreement, Pfizer will acquire ReViral for up to $525 million, including upfront and development milestones. The company believes annual revenue for programs related to the transaction could reach or exceed $1.5 billion.

“Since the foundation of the company a decade ago by Dr. Ken Powell and Dr. Stuart Cockerill, ReViral’s mission has always been to develop world-class therapies for RSV patients,” ReViral CEO Alex C. Sapir said. “This acquisition represents a validation of the deep antiviral experience of the ReViral team and our unwavering commitment to deliver therapies for patients in need. Pfizer is an optimal partner given their commitment to RSV through their ongoing RSV vaccine program, coupled with their world-class clinical, regulatory, manufacturing and commercial capabilities.

“We look forward to working with our colleagues at Pfizer to bring these therapies to patients as quickly as possible.”