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.
Patients with histologically confirmed Extensive-stage Small Cell Lung Cancer (ES-SCLC)
Patients without any previous systematic anti-cancer treatment for ES-SCLC. Patients who received previous systematic anti-cancer treatment during limited stage are eligible if the treatment has been completed more than 6 months before the diagnosis of ES-SCLC.
Adequate archival formalin-fixed paraffin-embedded (FFPE) tumour tissue, as specified in the Laboratory Manual, must be available for central laboratory analysis of Delta-like ligand 3 (DLL3) expression status and other biomarkers. The central laboratory investigational VENTANA DLL3 (SP347) RxDx test result must be available prior to randomisation.
Treatment for brain metastases (e.g. whole brain radiation therapy, stereotactic radiotherapy, or radiosurgery) completed at least 14 days prior to randomisation and neurologically stable without the use of glucocorticoids or therapeutic anti-convulsant for at least 7 days prior to randomisation
Presence of leptomeningeal disease and/or carcinomatous meningitis
Previous treatment targeting DLL3 (e.g. T cell engagers (TcEs), cell therapies, antibody-drug conjugates, or radiopharmaceuticals)
Radiotherapy of any anatomical sites within 14 days prior to randomisation
Persistent toxicity from previous treatments that has not resolved to ≤ Common Terminology Criteria for Adverse Events (CTCAE) Grade 1 (except for alopecia, asthenia/fatigue, amenorrhea/menstrual disorders, CTCAE Grade 2 peripheral neuropathy, and CTCAE Grade 2 endocrinopathies controlled by replacement therapy, and toxicities, which are considered irreversible but stable for at least 4 weeks prior to randomisation, per investigator judgment)