A Study of Dazostinag as Single Agent and Dazostinag in Combination With Pembrolizumab in Adults With Advanced or Metastatic Solid Tumors

The main aim of this study is to check if people with advanced solid tumors have side effects from dazostinag, and to check how much dazostinag they can receive without getting significant side effects from it when given alone and in combination with pembrolizumab. The study will be conducted in two phases including a dose escalation phase and a dose expansion phase. In the dose escalation phase, escalating doses of dazostinag are being tested alone and in combination with pembrolizumab to treat participants who have advanced or metastatic solid tumors. In the dose expansion phase, dazostinag will be studied with pembrolizumab with or without chemotherapy in participants with untreated metastatic or recurrent, unresectable squamous cell carcinoma of head and neck (SCCHN) and in combination with pembrolizumab in third-line or later recurrent locally advanced or metastatic microsatellite instability-high/mismatch repair deficient (MSI-H/dMMR) and third-line recurrent locally advanced or metastatic microsatellite stable/mismatch repair proficient (MSS/pMMR) colorectal cancer (CRC).