A Study to Evaluate Safety, Pharmacokinetics, and Preliminary Anti-tumor Activity of RO7444973 in Participants With Unresectable and/or Metastatic MAGE-A4-positive Solid Tumors

Key Inclusion Criteria:

* Unresectable and/or metastatic solid tumors that have received standard-of-care (SOC) therapies previously and have no other SOC options available
* Confirmed HLA-A\*02:01 haplotype
* Confirmed MAGE-A4 expression
* Radiologically measurable disease according to Response Evaluation Criteria in Solid Tumors (RECIST) v1.1
* Life expectancy of \>/=12 weeks
* Eastern Cooperative Oncology Group (ECOG) performance status of 0-1
* Absence of rapid disease progression, threat to vital organs or non-irradiated lesions \>2 cm in diameter at critical sites
* No significant ongoing toxicity from prior anticancer treatment
* Adequate hematological function
* Adequate liver function
* Adequate renal function
* If applicable, willingness to use contraceptive measures.

Key Exclusion Criteria:

* History or clinical evidence of CNS primary tumors or metastases
* Another invasive malignancy in the last 2 years
* Uncontrolled hypertension
* Significant cardiovascular disease
* Known active or uncontrolled bacterial, viral, fungal, mycobacterial, parasitic or other infection
* Current or past history of CNS disease
* Dementia or altered mental status that would prohibit informed consent
* Active auto-immune disease or flare within 6 months prior to start of study treatment
* Expected need for regular immunosuppressive therapy or with systemic corticosteroids
* Insufficient washout from prior anti-cancer therapy
* Prior treatment with a bispecific T-cell engaging or adoptive cell therapy.