Efficacy and Safety of Standard of Care Plus Durvalumab in Patients With Limited Disease Small Cell Lung Cancer (DOLPHIN)

Inclusion Criteria: * Signed and dated informed consent of the subject must be available before start of any specific trial procedures * Male or female ≥ 18 years * Histological confirmed limited disease small cell lung cancer (stage 2 and 3; T1a-4, N1-3, M0 according UICC8 criteria; if primarius is not eligible as RECIST1.1 target lesion (in cases with T1a and T1b) at least one lymph node must meet RECIST1.1 criteria for target lesion (≥15 mm short axis)) * Availability of tumor tissue or fresh tumor material for translational research by central lab testing * ECOG PS 0 - 1 * At least one measurable lesion according RECIST 1.1 * Body weight \> 30 kg * Adequate normal organ function 1. Hemoglobin ≥ 9.0 g/dL 2. Absolute neutrophil count (ANC) ≥ 1.5 x109/L 3. Platelet count ≥ 100 x109/L 4. AST (SGOT)/ALT (SGPT) ≤ 2.5 x institutional upper limit of normal 5. Serum Bilirubin ≤ 1.5 x institutional upper limit of normal 6. Estimated glomerular filtration rate (eGFR) ≥ 30 mL/min for Carboplatin, ≥ 60 mL/min for Cisplatin, calculated by the Cockcroft-Gault formula * Life expectancy of at least 12 weeks in the discretion of the investigator * Ability of subject to understand nature, importance and individual consequences of clinical trial Exclusion Criteria: * Extensive disease small cell lung cancer (Tx, Nx, M1; stage IV) * Major surgical process within 28 day prior first dose of IMP and/or Radiochemotherapy * History of allogenic organ transplantation * Active or prior documented autoimmune or inflammatory disorder (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: 1. Patients with vitiligo or alopecia 2. Patients with hypothyroidism (e.g. following Hashimoto syndrome) stable on hormone replacement 3. Patients with any chronic skin condition that not required systemic therapy 4. Patients without active disease in the last 5 years may be included but only after consultation with the study physician 5. Patients with celiac disease controlled by diet alone * Uncontrolled intercurrent illness (i.e. active infection, symptomatic congestive heart failure, uncontrolled hypertension, unstable angina pectoris, interstitial lung disease, serious chronic gastrointestinal conditions (i.e. diarrhea), psychiatric illness) * History of another primary malignancy in the last 5 years, except adequately treated nonmelanoma skin cancer, adequately treated carcinoma in situ (without evidence of disease) * History of leptomeningeal carcinomatosis, or brain metastases * Known HIV positive and/or active infection including tuberculosis (clinical evaluation that includes clinical history, physical examination and radiographic findings, and TB testing in line with local practice), hepatitis B (known positive HBV surface antigen (HBsAg) result), hepatitis C. Patients with a past or resolved HBV infection (defined as the presence of hepatitis B core antibody \[anti-HBc\] and absence of HBsAg) are eligible. Patients positive for hepatitis C (HCV) antibody are eligible only if polymerase chain reaction is negative for HCV RNA. * Current or prior use of immunosuppressive medication within 14 days before the first dose.The following are exceptions to this criterion: 1. Intranasal, inhaled, topical steroids, or local steroid injections (e.g., intra articular injection) 2. Systemic corticosteroids at physiologic doses not exceeding 10 mg/day of prednisone or its equivalent 3. Steroids as premedication for hypersensitivity reactions (e.g., CT scan premedication) * Receipt of live attenuated vaccine within 30 days prior to the first dose of IMP * Participation in another clinical trial with an investigational product within the last 30 days (unless during follow-up period of an interventional study) * Known hypersensitivity to one of the ingredients * Medical or psychological conditions that would jeopardize an adequate and orderly completion of the trial * Pregnancy, lactation and contraception 1. Women who are pregnant, nursing or who plan to become pregnant while in the trial 2. Women of child-bearing potential (WOCBP) and men who are able to father a child, unwilling to be abstinent or use highly effective methods of birth control that result in a low failure rate of less than 1% per year when used consistently and correctly beginning at informed consent, for the duration of drug treatment and for the drug out washout period (90 days after last dose of Durvalumab and/or 6 months after last dose of cisplatin/carboplatin and etoposide). * Patients who are legally institutionalized