Pfizer and LianBio have entered into a collaboration agreement on respiratory syncytial virus therapeutic candidates

On December 19, 2022, Pfizer's WeChat public platform said that Pfizer and LianBio announced that under the strategic cooperation agreement reached between the two parties to bring more innovative drugs to Greater China, Pfizer will exercise its option to obtain the development and commercialization rights of sisunatovir, a respiratory syncytial virus (RSV) treatment candidate, in Chinese mainland, Hong Kong, Macau and Singapore from LianBio.

Sisunatovir is an investigational oral fusion inhibitor designed to block RSV replication by inhibiting fusion of the F-protein-mediated virus with host cells. Sisunatovir is currently being evaluated as a potential therapy for the treatment of children and adults infected with RSV.

Jean-Christophe Pointeau, president of Pfizer's global biopharmaceutical business group in China, said "Pfizer has been committed to advancing the development of potentially critical vaccines and therapeutics to help address significant unmet medical needs in the treatment of infectious diseases, including respiratory syncytial virus, worldwide. We are excited to see the current range of collaborations with LianBio that have the potential to provide more patients with the treatments they desperately need." We believe that if the clinical study is successful and approved for marketing, sisunatovir has the potential to change the current standard of care for RSV patients, for whom we know that treatment options are currently limited. ”

Dr. Yizhe Wang, CEO of LianBio, said: "Like LianBio, Pfizer is aware that there are still significant gaps in the treatment of patients vulnerable to serious complications of RSV, and sisunatovir is expected to address this unmet medical need. During the typical RSV transmission season, more than 400,000 children and elderly patients in China were hospitalized for RSV-associated lower respiratory tract infections. Pfizer is a recognized leader in advancing RSV vaccine and therapeutics development, and their expertise in researching different treatment modalities enables new treatment options for as many patients as possible. ”

Sisunatovir, formerly a ReViral product, completed the acquisition of ReViral and the Company's RSV therapeutic candidate portfolio in June 2022, but this acquisition excludes the development and commercialization rights of Sisunatovir in the Chinese mainland, Hong Kong, Macau and Singapore regions, which was previously granted by ReViral in March 2021.

Under the terms of Pfizer's acquisition of the development and commercialization rights to Sisunatovir, LianBio will receive a total of $20 million in restricted cash paid by Pfizer to it in 2020 pursuant to the strategic partnership agreement between the parties. In addition, LianBio is eligible for potential development and commercial milestone payments of up to $135 million, as well as tiered sales share of a low-single-digit percentage of net sales of the drug in licensed territories. Pfizer will be responsible for all development and commercialization activities of Sisunatovir in the Licensed Territories and bear all associated costs; At the same time, LianBio's obligation to pay sales share and milestone payments in respect of sisunatovir will also be waived.