A Study of TPST-1120 With Atezolizumab Plus Bevacizumab in Patients With Unresectable or Metastatic HCC Not Previously Treated With Systemic Therapy

The goal of this clinical trial is to determine if TPST-1120 in combination with atezolizumab and bevacizumab helps patients to live longer compared to atezolizumab and bevacizumab alone (the standard of care treatment) in adult patients with hepatocellular carcinoma that cannot be removed by surgery or has spread outside of the liver (called metastatic). The trial also will study the safety and side effects of the drug combination compared to the standard of care treatment. Other questions the trial aims to answer include: 1. Does TPST-1120 in combination with atezolizumab and bevacizumab improve the time that patients are alive and cancer is not growing (progression free survival) compared to atezolizumab and bevacizumab 2. Does TPST-1120 in combination with atezolizumab and bevacizumab improve the shrinking of cancer (the overall response rate) compared to atezolizumab and bevacizumab Trial participants will be randomly assigned to take one of the following: 1. TPST-1120 3 tablets (600 mg) by mouth twice a day every day along with atezolizumab 1200 mg intravenously every 3 weeks and bevacizumab 15 mg/kg intravenously every 3 weeks 2. Placebo (look-alike that does not contain study drug) 3 tablets by mouth twice a day every day along with atezolizumab 1200 mg intravenously once every 3 weeks and bevacizumab 15 mg/kg intravenously once every 3 weeks Trial participants will receive routine and trial-specific cancer care from their study doctor including * visits to the clinic every 3 weeks for physical examination, labs and questions about health and symptoms * measurement of their cancer by CT scan every 9 weeks. Trial participants can stop study treatment at any time they choose and for any reason. They also can continue to receive study treatment for as long as the treatment is controlling cancer growth and they are tolerating the drug effects.