The purpose of this study is to determine the subcutaneous (SC) dose that gives rilvegostomig exposure comparable to the intravenous (IV) exposure, and to evaluate the pharmacokinetics (PK) and safety of SC rilvegostomig in adult participants with advanced solid tumors previously treated with standard of care therapy for whom immunooncology (IO) monotherapy would be deemed appropriate by the investigator.

This is a Phase I, open-label, multicenter, multi-part, dose finding and dose confirmation study to evaluate the PK and safety of SC rilvegostomig.

The study includes 2 parts: Part 1 (Dose Finding) and Part 2 (Dose Confirmation).

Part 1 will determine a SC rilvegostomig dose co-administered with rHu that yields drug exposure comparable with IV rilvegostomig. It will include 2 planned dose levels (DL1 in Cohort A and DL2 in Cohort B). Additional dose levels will be added, if needed.

Part 2 will be initiated once a dose has been identified based on Part 1. This part will evaluate the bioavailability, safety, and tolerability of SC rilvegostomig + rHu.

Inclusion Criteria:

• Histologically or cytologically documented advanced (metastatic and/or unresectable) solid tumor.
• Participants must have received prior anticancer treatment for the disease under study.
• IO monotherapy deemed appropriate by the investigator.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 at enrollment with no deterioration.
• Minimum life expectancy of ≥ 12 weeks at enrollment.
• Adequate organ and marrow function.
• Body weight ≥ 30 kg.

Exclusion Criteria:

• Any severe or uncontrolled systemic diseases, which makes it undesirable for the participant to participate in the study or that would jeopardize compliance with the protocol.
• History of organ transplant.
• History of another primary malignancy that was active within past 2 years.
• Persistent toxicities caused by previous anticancer treatment(s) excluding alopecia, not yet improved to Grade ≤ 1 or baseline.
• Unstable, symptomatic brain metastasis or spinal cord compression.
• History of leptomeningeal carcinomatosis.
• Active primary immunodeficiency/active infectious disease including tuberculosis (TB), human immunodeficiency virus (HIV) infection or hepatitis A, B or C infection.
• History of clinically significant arrhythmia, cardiomyopathy of any etiology; symptomatic congestive heart failure, history of myocardial infarction within the past 6 months.
• Uncontrolled intercurrent illness including but not limited to ongoing or active known infection; interstitial lung disease (ILD), serious chronic gastrointestinal conditions associated with diarrhea; active non-infectious skin disease requiring systemic treatment.
• Active or prior documented autoimmune or inflammatory disorders requiring chronic treatment with steroids or other immunosuppressive treatment.
• Known allergy or hypersensitivity to rilvegostomig, hyaluronidase, or any excipients of the investigational products.
• Participants experienced a toxicity to prior immunotherapy that led to permanent discontinuation of prior immunotherapy.
• Prior anticancer treatment, including immunotherapy, up to 28 days prior to the first dose of study treatment.

Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal Vivli.org. All requests will be evaluated as per the AZ disclosure commitment: https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

Yes, indicates that AZ are accepting requests for IPD, but this does not mean all requests will be shared.

AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA Pharma Data Sharing Principles. For details of our timelines, please rerefer to our disclosure commitment at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

When a request has been approved AstraZeneca will provide access to the anonymized individual patient-level data via secure research environment Vivli.org.

Signed Data Usage Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information.