The study will evaluate the safety and efficacy of lurbinectedin in combination with durvalumab as maintenance therapy in participants with ES-SCLC after first line induction therapy with durvalumab and platinum plus etoposide containing regimen. In order to be considered for eligibility screening for the maintenance phase, participants need to have an ongoing CR, PR, or stable disease (SD) per RECIST v1.1 criteria after completion of 4 cycles of platinum plus etoposide containing regimen with at least 3 cycles of durvalumab during induction treatment.
