A Study of PRT3789 in Combination With Pembrolizumab in Patients With Advanced or Metastatic Solid Tumors With a SMARCA4 Mutation

This is an open-label, multi-center Phase 2 study of PRT 3789, a first-in-class SMARCA2 targeted protein degrader, in combination with pembrolizumab, a potent humanized immunoglobulin G4 (IgG4) monoclonal antibody (mAb) with high specificity of binding to the programmed cell death 1 (PD-1) receptor, evaluating patients with Advanced or Metastatic Solid Tumors with a SMARCA4 Mutation. This study consists of 2 parts. Part 1 is a safety run-in and will establish the dose of PRT3789 to be used in combination with pembrolizumab in the main study (Part 2). For Part 2 (Main study) primary endpoints are ORR (defined as the proportion of patients with a confirmed best overall response of either complete response or partial response) and duration of response per investigator assessment per RECIST v1.1. Approximately 46 to 60 patients will be enrolled in Part 1 and Part 2 based on the dose of PRT3789 selected/cleared during the safety run-in.