Primary objective of this study is to evaluate the efficacy of AZD2811 and durvalumab in
      patients who have not progressed following induction therapy with platinum-based chemotherapy
      combined with durvalumab.

      This is an open-label, single arm study. Patients will be treated in an induction phase with
      platinum-based induction therapy and durvalumab. At the end of this induction period,
      participants will be assessed for disease progression, per RECIST v1.1.

      Participants who have not progressed per RECIST v1.1 at the end of the induction phase will
      roll over into the maintenance phase of the trial, where patients will commence AZD2811 and
      durvalumab combination.

      Participants will be treated with AZD2811 and durvalumab as maintenance therapy until
      confirmed progressive disease, start of non-protocol defined anticancer therapy, unacceptable
      toxicity, or withdrawal of consent.

      If study intervention is permanently discontinued, the participant will remain in the study
      to be evaluated for safety assessment, as well as for confirmed disease progression and for
      survival.

      Targeted population are adult patients (aged ≥18 years) with 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 have WHO/ECOG performance status of 0 or 1.

      Tumor assessments will be performed at Screening as baseline with follow-up every 6 weeks ± 1
      week for the first 36 weeks, and then every 8 weeks ±1 week until confirmed objective disease
      progression.