A Safety and Preliminary Efficacy Study of SBT6290 Alone and in Combination With PD-(L)1 Inhibitors in Select Advanced Solid Tumors

This is a first-in-human study designed to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics, immunogenicity, and preliminary antitumor activity of SBT6290 administered subcutaneously (SC) as a monotherapy and in combination with pembrolizumab in solid tumors associated with Nectin-4 expression. There are 4 parts to this study: * Part 1: A dose escalation of SBT6290 monotherapy * Part 2: Tumor-specific expansion cohorts evaluating SBT6290 monotherapy administered at the recommended phase 2 dose (RP2D) identified in Part 1 * Part 3: A dose escalation of SBT6290 in combination with pembrolizumab * Part 4: An expansion cohort of SBT6290 in combination with pembrolizumab administered at the RP2D identified in Part 3 for the combination