• Institutional Review Board (IRB)/Independent Ethics Committee (IEC) approved written informed consent.

• Patients ≥ 18 years of age.

• Patients who have histologically confirmed metastatic or locally advanced unresectable well/moderately differentiated; World Health Organization (WHO\]) 2015 criteria; neuroendocrine tumor of lung (typical and atypical carcinoids) or thymus origin either functioning or non-functioning.

• Patients must have the appropriate pathological features based on WHO classification, and description of proliferation activity as indicated by mitotic count per 10 high-power fields (HPF) and presence of necrosis, or Ki67 index.

• In SSTR imaging all RECIST v1.1 selected target lesions and all other lesions considered dominant by the investigator should be positive. If an fluorodeoxyglucose (FDG)-positron emission tomography (FDG-PET) is performed (not mandatory), all FDG-PET positive RECIST v1.1 target lesions and all other FDG-PET positive lesions considered dominant by the investigator should also be positive in SSRT imaging.

• Lesions must have shown radiological evidence of disease progression in the 12 months prior to inclusion in the study. Patients who were receiving systemic anticancer therapy, progression should be documented on therapy or after stopping therapy due to adverse events or other reasons. Patients without prior therapy, documentation of progression is also mandatory to watch and wait strategy or during the follow up after surgery.

• Patients may be included in first-line therapy (systemic treatment naïve) or may have experienced progression on somatostatin analogues or additional systemic treatments, which may include but not limited to chemotherapy, targeted agents or immunotherapy (maximum of 2 prior systemic anti-tumor treatments).

• Note: Somatostatin analogues for patients with functioning tumors are allowed.

• Patients have radiographically documented and measurable metastatic or locally advanced disease at baseline according to RECIST v1.1.

• An archival tumor tissue sample should be available for submission to the central laboratory prior to study treatment (36 months). If an archival tumor tissue sample is not available, a new biopsy tissue sample should be provided if feasible.

⁃ Patients who have Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.

⁃ Adequate organ and bone marrow function based upon meeting all of the following laboratory criteria:

∙ Neutrophil count (ANC) ≥ 1,500/mm\^3

‣ Platelet count ≥ 75 × 10\^9/L

‣ Hemoglobin ≥ 8 g/dL

‣ Serum bilirubin ≤ 1.5 × upper limit of normal (ULN) or ≤ 3 × ULN for subjects with Gilbert's disease or liver metastases

‣ Creatinine clearance (CrCl) ≥ 40 mL/min as estimated by the Cockcroft-Gault formula or as measured by 24-hour urine collection (GFR can also be used instead of CrCl). Note: renal tract obstruction is not allowed.

‣ Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 2.5 × ULN or ≤ 5 x ULN for subjects with liver metastases

⁃ Female subject must provide a negative urine pregnancy test at screening, and must agree to use a medically accepted and highly effective birth control method (i.e. those with a failure rate less than 1%) for the duration of the study treatment and for 6 months after the final dose of study treatment.

⁃ Female patients must agree not to breastfeed or donate ovules starting at screening and throughout the study period, and for at least 6 months after the final study drug administration.

⁃ Male patients must agree not to donate sperm starting at screening and throughout the study period, and for at least 6 months after the final study drug administration.

⁃ Male patients with a pregnant or breastfeeding partner(s) must agree to abstinence or use a condom for the duration of the pregnancy or time the partner is breastfeeding throughout the study period and for at least 6 months after the final study drug administration.

⁃ Subject agrees not to participate in another interventional study while on treatment in the present study.