Study of RYZ101 in Combination With SoC in Subjects With SSTR+ ES-SCLC

INCLUSION CRITERIA * Age of at least 18 years at the time of signing the informed consent. * Cytologically or histologically confirmed ES-SCLC (American Joint Committee on Cancer \[AJCC\] 8th edition) and is untreated or received ≤1 cycle of platinum-etoposide and PD-L1 inhibitor therapy. It is acceptable to omit the first dose of PD-L1 inhibitor therapy due to logistical reasons if receiving SoC during or prior to the start of the screening period. * Subject is a candidate for therapy with SoC which includes: * Carboplatin for a maximum of 4 cycles * Etoposide for a maximum of 4 cycles * Atezolizumab * At least 1SSTR-PET imaging-positive measurable site of disease (according to RECIST v1.1) and ≥50% of RECIST v1.1 measurable metastatic lesions must be SSTR-imaging positive. * Adequate hematologic, renal and hepatic function EXCLUSION CRITERIA * Prior exposure to immune-mediated therapy, * Known active or suspected autoimmune disease or any condition requiring systemic treatment with immunosuppressive medications within 14 days prior to first dose of study drug * History of idiopathic pulmonary fibrosis, organizing pneumonia (e.g., bronchiolitis obliterans), drug-induced pneumonitis, or idiopathic pneumonitis. Note: History of radiation pneumonitis is permitted. * Severe infection within 4 weeks and/or treatment with therapeutic oral or i.v. antibiotics within 2 weeks prior to initiation of study treatment. * Prior allogeneic stem cell or solid organ transplantation. * Treatment with a live, attenuated vaccine within 4 weeks prior to initiation of study treatment, or anticipation of need for such a vaccine during atezolizumab treatment or within 5 months after the final dose of atezolizumab. * Radiotherapy to the chest prior to systemic therapy or planned consolidation chest radiation therapy. Radiation therapy outside of the chest for palliative care is allowed but must be completed \>2 weeks prior to first dose of study drug. * Significant cardiovascular disease and/or resistant hypertension * Subjects with previously treated central nervous system (CNS) metastases who have not recovered from acute side effects of radiotherapy.