A First in Human Study of ALX2004 With Advanced or Metastatic Selected Solid Tumors

This is a first-in-human study testing a new experimental drug called ALX2004 in people with advanced or metastatic solid tumors, specifically head and neck cancers, non-small cell lung cancer, esophageal squamous cell cancer, and left-sided colorectal cancer. The goal is to determine a safe dose and assess early signs of effectiveness. **You may be eligible if...** - You have been diagnosed with one of the specific cancers listed above that has spread and cannot be surgically removed - You have already tried standard treatments that have not worked, or no approved options remain - Your overall health is adequate for cancer treatment (ECOG 0 or 1) **You may NOT be eligible if...** - You have active brain metastases - You have significant autoimmune disease requiring treatment - You have had certain prior treatments that disqualify you - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.