Brii Biosciences Limited (BRII-B) has disclosed that its wholly-owned subsidiary, Brii Biosciences Offshore Limited, has filed a demand for arbitration with Judicial Arbitration and Mediation Services, Inc. against U.S.-based Vir Biotechnology, Inc. The action alleges breaches of both their 2018 Collaboration, Option and License Agreement and a subsequent Sixth Letter Agreement signed on 19 December 2024, which shifted drug-product formulation manufacture for the elebsiran program from Vir to Brii.

The collaboration, first executed on 23 May 2018, grants each party options for exclusive licences to develop and commercialise the other’s product candidates. Brii exercised its option on 12 June 2020 for elebsiran, a small-interfering RNA candidate targeting hepatitis B virus.

According to the 22 May 2026 announcement, the arbitration is in its early stages and no resolution has been reached. Brii states that continued delays resulting from the dispute have created material uncertainty for the elebsiran program; the company will not commit resources to a Phase 3 clinical study of any elebsiran-containing combination therapy until the claims are settled.

Management will assess ongoing developments and update shareholders as required under Hong Kong listing regulations. Investors are advised to exercise caution when dealing in BRII-B shares.