Pfizer snaps up rights to RSV therapy left behind in ReViral buy for $20M

Pfizer, looking to be the king in respiratory syncytial virus vaccines and therapeutics, is going back to scoop up one therapy that was left on the table earlier this summer when the pharma giant acquired ReViral and its RSV portfolio.

The Big Pharma is paying $20 million cash to LianBio for the rights to develop and commercialize sisunatovir in Greater China. LianBio licensed the rights to the therapeutic from ReViral in 2021, meaning it was not a part of Pfizer's earlier deal.

But luckily for Pfizer, it has had a deal with Shanghai-based LianBio on the books since 2020, so snapping up the rights to sisunatovir was an easy fix. Pfizer has now agreed to pay $20 million upfront to bring the therapy under its wing as part of the 2020 collaboration. The company will now lead development and commercialization for sisunatovir in Mainland China, Hong Kong, Macau, and Singapore.

LianBio could be eligible for $135 million in development and commercial milestones plus tiered low single-digit percent of net sales associated with sisunatovir.

The 2020 deal meant $70 million for LianBio in exchange for granting Pfizer in-licensing, development and commercialization activities of certain products in Greater China. 

The first program to emerge from the partnership is the orally-delivered investigational RSV therapy, sisunatovir. The candidate is designed for both children and adults and aims to stop RSV replication by blocking F-mediated fusion with the host cell. The program, which has received fast-track designation from the FDA, reduced viral load in a phase 2 RSV study among healthy adults and is currently being assessed in a global phase 2 trial among children.

Pfizer acquired ReViral and its portfolio of RSV candidates earlier this summer for $525 million, marking a major move into RSV therapeutics. The Big Pharma is also pushing to get its RSV vaccine, dubbed RSVpreF, out the door. A few weeks ago, U.S. regulators granted a priority review for the shot, which is designed to prevent lower respiratory tract disease caused by RSV in people 60 years and older. The priority review means a decision on the vaccine’s approval will arrive four months earlier than normal. That sets a decision date for May, Pfizer said.  

Joining Pfizer in the race for an RSV vaccine are GSK, Johnson & Johnson, Bavarian Nordic and Moderna. The RSV push comes as the virus courses through the U.S. alongside COVID-19 and the flu.