Safety and Tolerability of ²¹²Pb-DOTAM-GRPR1 in Adult Subjects With Recurrent or Metastatic GRPR-expressing Tumors

This study tests a new radioactive drug called ²¹²Pb-DOTAM-GRPR1, which targets a protein (GRPR) found on certain tumors. It is being studied in adults with advanced cancers including prostate cancer, breast cancer, colorectal cancer, cervical cancer, lung cancer, and recurrent glioblastoma (brain tumor). The drug delivers targeted radiation directly to cancer cells. **You may be eligible if...** - You are 18 or older with one of the listed cancer types that has progressed after at least 2 prior treatments - A special scan (SPECT/CT) confirms your tumor has the GRPR target protein - Your blood counts, kidney, and liver function are adequate - For glioblastoma specifically: your tumor has come back after initial standard treatment **You may NOT be eligible if...** - Your ECOG performance status is worse than 1 (meaning your daily function is significantly limited) - Your kidney function is below the required threshold - Your tumor does not show GRPR uptake on scanning Talk to your doctor to see if this trial is right for you.