A Study of MT-303 in Adults With Advanced or Metastatic GPC3-Expressing Cancers, Including HCC

Inclusion Criteria

• Aged 18 years or older

• Histological diagnosis of advanced/recurrent or metastatic and/or unresectable HCC. [Note: participants with other tumor types expressing GPC3 may be eligible pending a discussion with the Medical Monitor]

• Measurable lesion per RECIST 1.1 criteria

• Eastern Cooperative Oncology Group (ECOG) performance status grade of 0 or 1

• Child-Pugh score: Class A

• Adequate organ function

Exclusion Criteria

• Known active central nervous system (CNS) metastasis and/or carcinomatous meningitis.

• Any acute illness including active infection

• History of liver transplantation or on waiting list

• Participants with untreated or incompletely treated varices with bleeding or high risk for bleeding

• Uncontrolled pleural effusion, pericardial effusion, or ascites

• History of symptomatic congestive heart failure

• History of chronic or recurrent (within the last year) severe autoimmune or immune mediated disease requiring steroids or other immune-suppressive treatments.