DAREON ® -Lung-1: A Study in People With Advanced Small Cell Lung Cancer to Compare Obrixtamig Plus Atezolizumab, Carboplatin, and Etoposide Treatment With Standard Chemoimmunotherapy

This study is open to adults with advanced small cell lung cancer (SCLC). The purpose of this study is to find out if a study medicine called obrixtamig plus standard treatment (atezolizumab, carboplatin, and etoposide) improves survival when compared to standard treatment alone. Obrixtamig is an antibody-like molecule that may help the immune system fight cancer. Another purpose of the study is to test a medical device being developed to measure levels of the tumour marker DLL3. Participants are put into 2 groups randomly, which means by chance. One group receives obrixtamig and standard treatment. The other group receives standard treatment without obrixtamig. All treatments are given as infusions into a vein. Participants are in the study for up to 3 years. During this time, they visit the study site regularly. Participants in the group receiving obrixtamig stay overnight at the study site following the first 2 obrixtamig treatments. At the visits, doctors check the size of the tumour(s). The results are compared between the 2 groups to see whether the treatment works. The doctors also regularly check participants' health and take note of any unwanted effects.