A Study to Investigate Efficacy and Safety of Ceralasertib Plus Durvalumab in Participants Aged ≥ 18 Years With Advanced or Metastatic Non-small Cell Lung Cancer Whose Disease Progressed on or After Prior Anti-PD-(L)1 Therapy and Platinum-based Chemotherapy

Prior treatment

• Brain metastases or spinal cord compression unless the participant is stable and off steroids.
• Persistent toxicities (CTCAE Grade \> 2) caused by previous anticancer therapy.
• Active or prior documented autoimmune or inflammatory disorders.
• Participants who have received more than one line of prior anti-PD-(L)1.
• Participants must not have experienced a toxicity that led to discontinuation of the prior anti-PD(L)1 therapy.
• Participants must not have experienced a Grade ≥ 3 immune-mediated adverse event (imAE) or an immune-related neurologic or ocular AE of any grade while receiving prior anti-PD(L)1 therapy.
• Participants must not have required the use of additional immunosuppression other than corticosteroids for the management of an AE, not have experienced recurrence of an AE if re-challenged.
• Participants who have received more than one prior line of platinum-based chemotherapy in metastatic setting.
• Participants who have received a prior ATR inhibitor.

Other illness

• History of leptomeningeal carcinomatosis.
• As judged by the investigator, any evidence of medical condition, which, in the investigator's opinion, makes it undesirable for the participant to participate in the study.

Other

• Participant with mixed SCLC and NSCLC histology.
• Diagnosis of ataxia telangiectasia.

• Histologically or cytologically documented NSCLC that is locally advanced or metastatic according to Version 8 of the IASLC Staging Manual in Thoracic Oncology.
• Documented epidermal growth receptor factor (EGFR) and anaplastic lymphoma kinase (ALK) wild-type status.
• Documented radiological PD whilst on or after receiving the most recent treatment regimen.
• Eligible for second- or third-line therapy and must have received an anti-PD-(L)1 therapy and a platinum doublet containing therapy for locally advanced or metastatic NSCLC.
• Eastern Cooperative Oncology Group (ECOG)/World Health Organization (WHO) performance status of 0 or 1.
• Adequate organ function and marrow reserve.
• Body weight \> 30 kg and no cancer-associated cachexia.