Vir Biotechnology is a clinical-stage biopharmaceutical company focused on developing treatments for serious infectious diseases and cancer, with no approved products or commercial revenue. Vir's lead program is a combination therapy of tobevibart and elebsiran for chronic hepatitis delta (CHD), a severe liver disease with no FDA-approved treatment in the U.S. The combination targets the hepatitis B surface antigen that HDV requires to replicate via two complementary mechanisms. Three Phase 3 registrational trials are underway, with topline data expected in late 2026 to early 2027. If approved, Vir plans to commercialize the combination in the U.S. itself via a targeted specialty sales force, while Norgine holds commercial rights in Europe, Australia, and New Zealand. Vir's oncology pipeline centers on three clinical-stage masked T-cell engagers (TCEs) for solid tumors: VIR-5500 (PSMA-targeted, prostate cancer), VIR-5818 (HER2-targeted), and VIR-5525 (EGFR-targeted), all using Sanofi's PRO-XTEN masking platform, which keeps the drug inactive until tumor-specific proteases activate it at the tumor site — designed to reduce the toxicity that has historically limited TCEs. VIR-5500 is partnered with Astellas, which is providing $335M in upfront and near-term payments. Vir funds its operations through its cash balance and business development deals, having also licensed HDV rights to Norgine for €55M upfront plus milestones and royalties. Vir has meaningfully cut cash burn through restructuring since 2023 and ended Q3 2025 with roughly $811M in cash.