∙ Criteria for Screening

• Patient must have signed a first written informed consent form prior to screening visit and to any trial specific procedures.

• Histological confirmation of SCLC.

• Limited disease (T0-T4, N0-N3 and M0) according to the TNM classification 8th edition or to the VALSG 2-stage classification. As per standard guidelines a complete radiological evaluation has to be performed within 28 days before the start of induction chemotherapy including all the radiological exams below:

‣ Total body PET- scan.

⁃ Contrast enhanced CT-scan of thorax and upper abdomen.

⁃ Contrast enhanced MRI or CT-scan of brain.

• Measurable disease according to RECIST v1.1 criteria.

• Patients must not have been previously treated for the SCLC. Note: patients who have already begun the initial CRT are eligible.

• Patients ≥18 years old.

• Body weight \>30 kg.

• Patients can be candidate to concomitant or sequential thoracic CRT by IMRT. Patients have to receive at least 60 Gy (one-daily fraction of 1.8-2 Gy) or 45 Gy twice daily (1.5 Gy per fraction) combined with cisplatin-etoposide regimen or with carboplatin AUC5 to AUC6 etoposide regimen.

• Patients that received previous thorax radiotherapy may be eligible if they can receive the CRT schedule planned in the clinical study according to previous irradiation fields and, in any case, after the medical monitor agreement.

⁃ Women of childbearing potential must have a negative serum beta-HCG test before the beginning of the trial, during the study treatment and for a period of at least 3 months after the last administration of the experimental drug.

⁃ All sexually active men and women of childbearing potential must use an effective contraception method for the duration of study treatment and for 3 months after completing treatment.

⁃ Patients affiliated to the social security system.

⁃ Patient must be willing and able to comply with the protocol for the duration of the trial including undergoing treatment and scheduled visits, and examinations including follow-up.

∙ Criteria for Inclusion:

• Patient must have signed a second written informed consent form prior to inclusion and to any specific trial procedure.

• Patients must have completed concomitant or sequential thoracic CRT by IMRT:

• Patients that received concomitant or sequential thoracic CRT must have received at least 60 Gy (one-daily fraction of 1.8-2 Gy) or 45 Gy twice daily (1.5 Gy per fraction) combined with cisplatin-etoposide regimen or with carboplatin AUC5 to AUC6 etoposide regimen.

• Confirmation of disease control (SD, CR or PR) at radiological assessment with contrast enhanced thorax and upper abdomen CT-scan or PET-CT and contrast enhanced brain CT-scan or MRI after the thoracic CRT according to RECIST v1.1.

• Use of brain MRI in case of PCI avoidance is mandatory. PCI has to be prescribed according to the investigator's choice and the local recommendations.

• Body weight \>30 kg

• Patients must belong to one of these groups at the screening visit after the thoracic CRT :

‣ ECOG PS 2.

⁃ ECOG PS 0-1 and older than 70.

⁃ ECOG PS 0-1 and who did not receive a concomitant thoracic CRT because of comorbidities (radiotherapy beginning before D1C3 of chemotherapy).

• Adequate haematological function

‣ Haemoglobin \>9 g/dL.

⁃ Platelet count \>100 x 10⁹L.

⁃ Neutrophil count \>1.5 x 10⁹L.

• Adequate renal function with a creatinine clearance ≥40 ml/min calculated with the Cockcroft-Gault formula.

• Adequate hepatic function:

‣ Total bilirubin \<1.5 Upper limit of normal (ULN).

⁃ AST and ALT \<2.5 ULN.

⁃ Alkaline phosphatase \<2.5 ULN.

⁃ HRQoL questionnaire performed.

⁃ Any unresolved toxicity NCI CTCAE Grade ≥2 from previous anticancer therapy with the exception of alopecia, vitiligo, and the laboratory values defined in the inclusion criteria.