Study of Sacituzumab Govitecan With Atezolizumab/Durvalumab as Maintenance Therapy for Extensive-Stage Small Cell Lung Cancer

Inclusion Criteria:

* Participant is willing and able to give informed consent for participation in the trial.
* Male or Female aged 18 years or above.
* Participants must have a histologically or cytologically confirmed diagnosis of small cell lung cancer (SCLC) and extensive stage at diagnosis or locally advanced disease and unable to receive curative intent radiation.
* Participants must have received at least four cycles of platinum plus etoposide and at least 2-3 cycles of atezolizumab/ Durvalumab.
* No evidence of progression on restaging CT CAP following 4-6 cycles of Chemo/IO from the last dose of the chemotherapy cycle.
* ECOG performance status of 0-2
* Patients must not have active uncontrolled HIV, HBV, and HCV infections. Well-controlled infections on treatment will be allowed to participate in the trial.
* Patients with stable and asymptomatic brain metastasis.
* Adequate organ function - bone marrow, kidney, and liver.

Exclusion Criteria:

* Significant renal impairment requiring dialysis or hepatic impairment with end-stage liver disease.
* Participants with leptomeningeal disease.
* Participants with a recent diagnosis of heart failure and acute coronary disease within 3 months.
* Participants who are unable to receive immunotherapy with chemotherapy for induction will be excluded, or those immunotherapy was discontinued to manage immune-related adverse events
* Active chronic inflammatory bowel disease (ulcerative colitis, Crohn's disease) or gastrointestinal perforation within 6 months of enrolment.
* Patients with prior exposure to anti-PD-1, anti-PD-L1, or anti-PD-L2 agents or with an agent directed to another stimulatory or coinhibitory T-cell receptor (eg, CTLA-4) within 12 months of the study is not allowed.