FIRST-NEC (GFPC 01-2022) - Combination of Durvalumab With Etoposide and Platinum

Inclusion Criteria: 1. Age ≥ 18 years at the time of study entry; 2. Locally documented histological diagnosis of Large-Cell NeuroEndocrine Carcinoma of the lung (2021 WHO classification of Lung Tumors ); 3. Patient must have sufficient material to achieve central histological confirmation and exploratory analyses (1 representative FFPE block or at least 10 unstained slides); 4. Setting of the disease: locally advanced (Stage III) not eligible for loco-regional therapy or metastatic (Stage IV) in first line treatment (8th TNM classification). Nota Bene: patients with recurrence of local or locally advanced LCNEC are eligible to the trial provided that recurrence occurs beyond 3 months after the last chemotherapy administration. For relapsing patients, tumor material collected at diagnosis can be used for the FIRST-NEC trial if relapse occurs within two years of initial management and if initial histologic tumor material is available. 5. Measurable disease as per the RECIST 1.1; 6. Performance Status (PS) of the Eastern Cooperative Oncology Group (ECOG): 0 or 1 ; 7. Body weight \> 30Kg; 8. Must have a life expectancy of at least 12 weeks; 9. Adequate normal organ and marrow function as defined below: * Haemoglobin ≥8.0 g/dL (with or without transfusion) * Absolute neutrophil count (ANC) ≥1.5 × 109 /L * Platelet count ≥100 × 109/L * Serum bilirubin ≤1.5 x institutional upper limit of normal (ULN)), or ≤3.0xULN in case of liver metastases. Note: this will not apply to patients with confirmed Gilbert's syndrome (persistent or recurrent hyperbilirubinemia that is predominantly unconjugated in the absence of hemolysis or hepatic pathology), who will be allowed only in consultation with their physician. * AST (SGOT)/ALT (SGPT) ≤2.5 x institutional upper limit of normal unless liver metastases are present, in which case it must be ≤5x ULN * For patients undergoing a treatment by cisplatin: measured creatinine clearance (CrCl) ≥60 mL/min or Calculated creatinine CrCl ≥60 mL/min by the CKD-EPI equation or by 24-hour urine collection for determination of creatinine clearance (CrCl). Nota Bene: if creatinine clearance is \<60 ml/min, patients must be treated with carboplatin rather than cisplatin. 10. Evidence of post-menopausal status or negative urinary or serum pregnancy test for female pre-menopausal patients. Women will be considered post-menopausal if they have been amenorrheic for 12 months without an alternative medical cause. The following age-specific requirements apply: * Women \<50 years of age would be considered post-menopausal if they have been amenorrheic for 12 months or more following cessation of exogenous hormonal treatments and if they have luteinizing hormone and follicle-stimulating hormone levels in the post-menopausal range for the institution or underwent surgical sterilization (bilateral oophorectomy or hysterectomy). * Women ≥50 years of age would be considered post-menopausal if they have been amenorrheic for 12 months or more following cessation of all exogenous hormonal treatments, had radiation induced menopause with last menses \>1 year ago, had chemotherapy-induced menopause with last menses \>1 year ago, or underwent surgical sterilization (bilateral oophorectomy, bilateral salpingectomy or hysterectomy). 11. Patient (male or female) using a highly effective contraception as defined in during the treatment period and at least up to 6 months after the last administration of chemotherapy or 90 days after the last administration of durvalumab, whichever is longer. Prior to dispensing study drugs, the investigator must confirm and document the patient's (and his/her partner) use of highly effective contraceptive methods, dates of negative pregnancy tests, and confirm the patient's understanding of the teratogenic potential of study drugs; 12. Patient is willing and able to comply with the protocol for the duration of the study including undergoing treatment and scheduled visits and examinations including follow up. 13. Affiliation to a social security system; 14. Capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol. Written informed consent obtained from the patient prior to performing any protocol-related procedures, including screening evaluations. Exclusion Criteria: 1. Concurrent enrolment in another clinical study, unless it is an observational (non-interventional) clinical study or during the follow-up period of an interventional study (wash-out period of 28 days); 2. Patient previously treated for a LCNEC in a metastatic setting; 3. Any previous treatment with a PD1 or PD-L1 inhibitor, including durvalumab; 4. Any concurrent chemotherapy, Investigational product, biologic, or hormonal therapy for cancer treatment. Concurrent use of hormonal therapy for non-cancer-related conditions (e.g., hormone replacement therapy) is acceptable; 5. Major surgical procedure (as defined by the Investigator) within 21 days prior to the first dose of study drugs; Note: Local surgery or radiotherapy of isolated lesions for palliative intent is acceptable. 6. History of allogenic organ transplantation; 7. Active or prior documented autoimmune or inflammatory disorders (including inflammatory bowel disease \[e.g., colitis or Crohn's disease\], diverticulitis \[with the exception of diverticulosis\], systemic lupus erythematosus, Sarcoidosis syndrome, or Wegener syndrome \[granulomatosis with polyangiitis\], Graves' disease, rheumatoid arthritis, hypophysitis, uveitis, etc). The following are exceptions to this criterion: * Patients with vitiligo or alopecia * Patients with hypothyroidism (e.g., following Hashimoto syndrome) stable on hormone replacement * Any chronic skin condition that does not require systemic therapy * Patients without active disease in the last 5 years may be included but only after co