A Phase III, Randomized, Multicenter, Open-Label, Comparative Study to Determine the Efficacy of Durvalumab or Durvalumab and Tremelimumab in Combination With Platinum-Based Chemotherapy for the First-Line Treatment in Patients with Extensive Disease Small-Cell Lung Cancer (SCLC)

-Male or female >=18 years at the time of Screening.
-Written informed consent and any locally required authorization obtained from
the patient/legal representative prior to performing any protocol-related
procedures, including screening evaluations.
-Histologically or cytologically documented extensive disease (American Joint
Committee on Cancer Stage (7th edition) IV SCLC [T any, N any, M1 a/b]), or T3-
4 due to multiple lung nodules that are too extensive or have tumor/nodal
volume that is too large to be encompassed in a tolerable radiation plan.
-Patients must be considered suitable to receive a platinum based chemotherapy
regimen as 1st line treatment for the ED-SCLC. Chemotherapy must contain either
cisplatin or carboplatin in combination with etoposide.
-Life expectancy >=12 weeks at Day 1.
-World Health Organization (WHO)/Eastern Cooperative Oncology Group (ECOG)
Performance Status of 0 or 1 at enrollment
-At least 1 lesion, not previously irradiated, that can be accurately measured
at baseline as >=10 mm in the longest diameter (except lymph nodes which must
have a short axis >=15 mm) with computed tomography (CT) or magnetic resonance
imaging (MRI) and that is suitable for accurate repeated measurements as per
RECIST 1.1 guidelines.
-No prior exposure to immune-mediated therapy including, but not limited to,
other anti-CTLA-4, anti-PD-1, anti-PD-L1, and anti-programmed cell death ligand
2 (anti-PD-L2) antibodies, excluding therapeutic anticancer vaccines.
- Adequate organ and marrow function

- Involvement in the planning and/or conduct of the study (applies to both
AstraZeneca staff and/or staff at the study site).
- Previous IP assignment in the present study.
- Concurrent enrollment in another clinical study, unless it is an
observational (non-interventional) clinical study or during the follow-up
period of an interventional study.
- Participation in another clinical study with an IP during the last 4 weeks.
- Medical contraindication to etoposide-platinum (carboplatin or
cisplatin)-based chemotherapy
- Any history of radiotherapy to the chest prior to systemic therapy or planned
consolidation chest radiation therapy.
- Any concurrent chemotherapy, IP, biologic, or hormonal therapy for cancer
treatment.
- Major surgical procedure (as defined by the investigator) within 28 days
prior to the first dose of IP.
- History of allogenic organ transplantation.
- Has a paraneoplastic syndrome (PNS) of autoimmune nature, requiring systemic
treatment (systemic steroids or immunosuppressive agents) or has a clinical
symptomatology suggesting worsening of PNS.
- Active or prior documented autoimmune or inflammatory disorders
- Uncontrolled intercurrent illness.
- History of another primary malignancy
- History of leptomeningeal carcinomatosis.
- History of active primary immunodeficiency.
- Active infection including tuberculosis, hepatitis B, hepatitis C, or human
immunodeficiency virus (positive HIV 1/2 antibodies).
- Current or prior use of immunosuppressive medication within 14 days before
the first dose of durvalumab or tremelimumab.
- Receipt of live, attenuated vaccine within 30 days prior to the first dose of
IP.
- Female patients who are pregnant or breastfeeding or male or female patients
of reproductive potential who are not willing to employ effective birth control
from Screening to 90 days after the last dose of durvalumab monotherapy or 180
days after the last dose of durvalumab + tremelimumab combination therapy.
- Known allergy or hypersensitivity to durvalumab, tremelimumab, etoposide,
carboplatin, cisplatin, or any of their excipients
- Prior randomization or treatment in a previous durvalumab and/or tremelimumab
clinical study regardless of treatment arm assignment.