A Phase II, Study to Determine the Preliminary Efficacy of Novel Combinations of Treatment in Patients With Platinum Refractory Extensive-Stage Small-Cell Lung Cancer

Durvalumab + tremelimumab via intravenous (IV) infusion every 4 weeks (q4w), starting on Week 0, for up to a total of 4 months (4 cycles) followed by durvalumab monotherapy via IV infusion q4w, starting on Week 16 until PD, or for other discontinuation criteria.

AZD1775 twice daily (oral) for 2.5 days from Day 1 + CBDP area under the curve 5 (Day1) (IV); every 3 weeks.

AZD6738 once a day (oral) for 7 days from Day 1 + olaparib twice a day(oral) for 28 days from Day 1, every 4 weeks