A Study of BL-M17D1 in Patients With Locally Advanced or Metastatic HER2 Positive/Lower Expression Gastrointestinal Cancer and Other Solid Tumors

This study is testing a new antibody-drug conjugate called BL-M17D1 — a targeted therapy that delivers chemotherapy directly to cancer cells with HER2 protein on their surface — in patients with advanced gastrointestinal cancers and other solid tumors. **You may be eligible if...** - You are 18 or older (up to 75 for the first phase) with confirmed advanced or metastatic gastrointestinal cancer or other solid tumor that has HER2 expression (positive or low levels) - Your expected survival is at least 3 months - You have at least one measurable tumor and are willing to provide a tissue sample - Your general health score and organ function are adequate **You may NOT be eligible if...** - Your tumor has no HER2 expression - You have active brain metastases, serious lung inflammation, or uncontrolled infections - You have had prior treatments that specifically disqualify you - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.