Study of SYN818 With Olaparib for the Treatment of Locally Advanced or Metastatic Solid Tumors

This trial tests a combination of two drugs — SYN818 and olaparib — for people with advanced or metastatic solid tumors, particularly ovarian cancer or HER2-negative breast cancer, who carry BRCA gene mutations or similar DNA repair defects. Both drugs target cancer cells with broken DNA repair systems. **You may be eligible if...** - You are 18 or older with an advanced or metastatic solid tumor and have exhausted all standard treatment options - You have confirmed BRCA mutations or a similar DNA repair deficiency (called HRD) - For Part 2: you have locally advanced or metastatic ovarian cancer or HER2-negative breast cancer - You have at least one measurable tumor on imaging **You may NOT be eligible if...** - You have previously taken a DNA Polymerase Theta (POLQ) inhibitor drug - You have another active cancer (unless treated and in remission for 5+ years) - You have symptomatic or uncontrolled cancer spread to the brain - You have a history of MDS or AML Talk to your doctor to see if this trial is right for you.