Symbiotic-GI-13: A Study to Learn About Study Medicine Called PF-08634404 as a Single Treatment and Combination Treatment in Adult Participants With a Liver Cancer Called Hepatocellular Carcinoma, That is Too Advanced to be Removed by Surgery and May Have Spread to Other Parts of the Body

This research study is evaluating a new investigational treatment for patients with advanced Hepatocellular carcinoma, the most common type of liver cancer. The study will look at the safety and effectiveness of the investigational drug PF-08634404 when given alone or in combination with the immunotherapy medicine Ipilimumab. Researchers want to learn whether these treatments can help slow or stop the growth of liver cancer and better understand possible side effects. Information from this study may help improve future treatment options for patients with advanced liver cancer.

• Adults 18+ years of age
• Diagnosed with unresectable or metastatic Hepatocellular carcinoma
• Have at least one measurable tumor on imaging
• No significant uncontrolled medical conditions
• No active serious infections
• No history of severe autoimmune disease requiring immunosuppression
• No prior organ transplantation or other conditions that would make participation unsafe or interfere with study results

• Receiving the study treatment, which may include the investigational drug PF-08634404 alone or in combination with Ipilimumab, given through intravenous (IV) infusion
• Attending regular visits for monitoring, including physical exams, blood tests, and scans to see how the cancer is responding and to check for side effects.
• Attending follow-up visits after treatment ends.