A Phase 1 Study of JMT108 in Participants With Advanced Solid Tumors

The goal of this clinical trial is to test JMT108, a type of drug called a bispecific antibody in adult patients with locally advanced or metastatic solid tumors. The main questions it aims to answer are: * To assess the safety and tolerability of JMT108 at increasing doses and determine the dose and schedule to be used in the second part of the study (Phase 1a) * To assess effectiveness of JMT108 in participants with locally advanced or metastatic tumors (Phase 1b) * To evaluate how quickly JMT108 is metabolized by the body (pharmacokinetics or PK) * To evaluate if antibodies to the study drug develop (immunogenicity) * To evaluate preliminary efficacy to the drug * To explore the pharmacodynamic (PD) characteristics of JMT108 * To explore the correlation between biomarker levels and preliminary efficacy Participants will: * Provide written informed consent * Undergo screening tests to ensure they are eligible for study treatment * Attend all required study visits and receive JMT108 by intravenous injection every 2 weeks until the study doctor determines study treatment should be stopped, based on how well a participant is doing on treatment * Be followed for progression every 3 months for up to 2 years