atezolizumab

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.