Study of the Theranostic Pair RYZ811 (Diagnostic) and RYZ801 (Therapeutic) to Identify and Treat Subjects With GPC3+ (Glypican-3) Unresectable HCC

This study tests RYZ801 (a targeted radiation therapy) and its diagnostic partner RYZ811 (an imaging agent) in patients with advanced liver cancer (HCC) whose tumors express the GPC3 protein, offering a 'theranostic' approach — diagnose and treat with matched tools. **You may be eligible if...** - Age 18 or older - Have advanced liver cancer (hepatocellular carcinoma) confirmed by biopsy or cytology - Have advanced-stage disease (BCLC Stage C, or Stage B not suitable for local treatments) - Have preserved liver function (Child-Pugh A) - Good performance status (ECOG 0–1) - At least one prior line of systemic therapy **You may NOT be eligible if...** - Liver function is too impaired (Child-Pugh B or C) - Have had certain prior liver-directed or systemic treatments that are excluded - Cancer has spread to the brain - Have serious heart, kidney, or autoimmune conditions Talk to your doctor to see if this trial is right for you.