First in Human Study to Evaluate AZD9793 in Participants With Advanced or Metastatic Solid Tumours

Key Inclusion Criteria: * Age ≥ 18 at the time of signing the informed consent. * GPC3 positive tumour as determined by a central laboratory using an analytically validated IHC assay. * Must have at least one measurable lesion according to Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 * Eastern Cooperative Oncology Group Performance status (ECOG PS): 0-1 at screening. * Predicted life expectancy of ≥ 12 weeks. * Adequate organ and bone marrow function measured within 28 days prior to first dose as defined by the protocol. * Contraceptive use by men or women should be consistent with local regulations, as defined by the protocol. * Confirmed advanced recurrent and/or metastatic and/or unresectable HCC, which is histopathologically proven based on the criteria established by the World Health Organization. * Barcelona Clinic Liver Cancer (BCLC) stage B (that is not eligible for locoregional therapy) or stage C. * Child-Pugh Score class A. * Previous therapy: Part A: Patients who have received at least one prior line of standard systemic therapy for HCC as per National Comprehensive Cancer Network or other local scientific guidelines and for which a clinical study is the best option for next treatment based on prior response and/or tolerability and/or patient/investigator decision. Part B: Patients must not have received more than one prior line of systemic therapy in the advanced recurrent and/or metastatic setting. Key Exclusion Criteria: * Unresolved toxicity from prior anticancer therapy, including imAEs, of Common Terminology Criteria for Adverse Events (CTCAE) Grade ≥ 2 except for vitiligo, peripheral neuropathy related to prior anti-cancer therapy, alopecia, endocrine disorders that are controlled with replacement hormone therapy and asymptomatic laboratory abnormalities. * Prior to enrolment, participation in another clinical study with an investigational product administered in the last 21 days or 5 half-lives whichever is shorter. * CAR-T cell therapy within the last 6 months prior to enrolment on this study. * Known allergy or hypersensitivity to AZD9793 or any of the excipients of the product as outlined in the IB. * Requires chronic immunosuppressive therapy (including steroids \> 10 mg prednisone/day or equivalent). * Prior treatment with any therapy that is targeted to GPC3. * Received radiation within 14 days prior to first dose of study treatment; palliative radiation to reduce the risk of tumour lysis syndrome (TLS) or CRS/neurotoxicity in participants with bulky disease is permitted. * Undergone a major surgical procedure within 14 days prior to first dose of study treatment days to allow adequate healing * Experienced unacceptable cytokine release syndrome (CRS) or Immune Effector Cell Associated Neurotoxicity (ICANS) following prior T cell engagers (TCE) or chimeric antigen receptor T (CAR-T) cell therapy. * Previous history of hemophagocytic lymphohistiocytosis (HLH) / macrophage activation syndrome (MAS). * Active or prior documented autoimmune or inflammatory disorders within 3 years of start of treatment. * Cardiac conditions as defined by the protocol. * History of thromboembolic event within the past 3 months prior to the scheduled first dose of study intervention. * Central nervous system (CNS) metastases or CNS pathology, as defined by the protocol, within 3 months prior to consent. * Infectious disease including active human immunodeficiency virus (HIV), and uncontrolled active systemic fungal, bacterial or other infection. * Known fibrolamellar HCC, sarcomatoid HCC, or combined hepatocellular malignant cholangiocarcinoma.