Vir, WuXi Biologics terminate COVID antibody pact as US rollout faces uncertain future

The U.S. distribution of Vir Biotechnology’s GSK-partnered COVID-19 antibody has been put on hold for more than a month. Now, a collaborator in the therapy wants out.

WuXi Biologics has returned China rights to Vir’s COVID antibody, sotrovimab, the latter company said in a securities filing (PDF) published Friday.

As part of the termination agreement, Vir will pay WuXi Bio $7 million to cover the Chinese CDMO’s development expenses. If sotrovimab is eventually approved in China, Vir is also on the hook to pay WuXi Bio tiered royalties on sales ranging from low single-digit percentages to low double-digit percentages, the company said.

The two companies tied the knot at the beginning of the pandemic back in February 2020. Under the deal, WuXi developed the cell line, process and formulation of Vir’s COVID antibody candidates and manufactured initial supply for clinical development. In return, WuXi obtained rights to sell the therapies in China.

WuXi exited the deal as the COVID situation has been brought under control, CEO Chris Chen, Ph.D., said, as quoted by China’s business news outlet Yicai. The CDMO contracts between the two firms remain ongoing, according to Chen and Vir.

Before WuXi and Vir parted ways, the U.S. federal government suspended distribution of sotrovimab in April because the drug appeared to be ineffective against the dominant omicron BA.2 subvariant.

Meanwhile in China, local authorities in December approved Brii Biosciences’ COVID antibody cocktail for patients with “mild and normal” disease at high risk for progression. The combo of amubarvimab and romlusevimab scored a spot on China’s COVID treatment guidelines in March, and Brii has tapped state-owned Sinopharm for distribution. WuXi Bio is also the CDMO for that therapy.

Earlier this month, Brii said its antibody combo retains neutralizing activity against the BA.2 subvariant based on tests in lab dishes.

WuXi is walking away from sotrovimab not just because there’s already a rival drug with potent efficacy but also because the overall Chinese COVID market is probably not big enough for two antibody therapies.

China has been experiencing waves of omicron outbreaks lately, but, as WuXi’s Chen told Yicai, antibody drugs are pricey and not widely utilized. Even during flare-ups, the number of cases has remained low amid tight anti-COVID measures.

Chinese regulators in February offered emergency clearance to Pfizer’s oral antiviral drug Paxlovid. During an ongoing outbreak in Shanghai, mainly Paxlovid and traditional Chinese medicines have been used to treat COVID patients, Yicai reported.