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. Patients who previously received any therapy targeting GPC3 must undergo central laboratory GPC3 testing on tumour tissue collected after completion of the prior GPC3-targeted therapy. * 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). * 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.