To Access the Safety and Effects of Intravenous Administration of VIR-5818 Alone and in Combination With Pembrolizumab in Adult Participants With Locally Advanced or Metastatic HER2-Expressing Cancers

This first-in-human (FIH) Phase 1 open-label multicenter dose-escalation and dose-expansion study is designed to evaluate the safety, pharmacokinetics, and preliminary activity of VIR-5818 (Formerly AMX-818) as a single agent and in combination with pembrolizumab in participants with HER2+ tumors across multiple tumor types. The study will be conducted in four parts: * Part 1 (dose escalation): Single-agent VIR-5818 * Part 2 (dose escalation): VIR-5818 plus pembrolizumab * Part 3 (dose expansion): Single-agent VIR-5818 * Part 4 (dose expansion): VIR-5818 plus pembrolizumab The total length of the study, from screening of the first participant to the end of the study, is expected to be approximately 52 months.

NCT Number	NCT05356741
Lead Sponsor	Vir Biotechnology, Inc. Collaborators: Merck Sharp & Dohme LLC
Conditions	Locally Advanced or Metastatic HER2-Expressing Cancers
Enrollment	645 participants
Start Date	2022-04-13
Primary Completion	2027-08-16 (estimated)
Study Completion	2027-08-16 (estimated)
Updated on ClinicalTrials.gov	2025-09-24