This is an early phase trial designed to evaluate the safety, tolerability, and preliminary antitumor activity of RPTR-1-201 in adults with advanced solid tumors. The trial includes dose escalation and dose expansion parts and will evaluate RPTR-1-201 as monotherapy and in combination with an anti-PD-1 monoclonal antibody.

Inclusion Criteria

• Histologically or cytologically confirmed locally advanced or metastatic solid tumors that is not amenable to curative treatment.
• At least one measurable lesion per RECIST v1.1 as assessed by the investigator.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
• Adequate organ function as defined in the trial protocol.
• Ability to provide written informed consent and comply with trial procedures.

Exclusion Criteria:

• History of another malignancy within 3 years before the first dose of trial intervention, with the exception of malignancies considered cured and not expected to require active therapy (for example, certain skin cancers or in situ malignancies) per protocol.
• Known active leptomeningeal disease or uncontrolled central nervous system metastases.
• Active, clinically significant, autoimmune diseases requiring systemic immunosuppressive therapy.
• Prior allogenic organ transplantation
• Clinically significant uncontrolled medical or psychiatric condition, that in the opinion of the investigator, would increase risk or interfere with trial participation.
• Other protocol-defined inclusion and exclusion criteria apply

Individual participant data will not be shared for this trial.