HER2 Expressing Solid Tumors

This is a Phase 1/2, first-in-human, open-label, dose-escalating and expansion trial designed to assess the safety and efficacy of VNX-202 in patients with HER2 positive cancers.

This clinical trial is designed to evaluate the safety, pharmacokinetics, pharmacodynamics, and preliminary efficacy of MT-304 in adults with advanced HER2-expressing solid tumors. The main questions it aims to answer are: * What is the safety profile of MT-304 when administered alone or with nivolumab? * What is the recommended Phase 2 dose (RP2D) of MT-304? Participants will: * Receive MT-304 alone (every 14 days) or with nivolumab (every 28 days). * Attend regular clinic visits for assessments and monitoring. * Continue treatment until disease progression, unacceptable toxicity, or study discontinuation.