Extensive stage small cell lung cancer (SCLC) has historically been associated with limited treatment options and a poor prognosis. In recent years, immunotherapy with PD-1 and PD-L1 targeting antibodies has emerged as an effective treatment option for these patients with progressive disease. Recently, the PD-L1 inhibitor atezolizumab was approved for use in the first-line setting in combination with chemotherapy, based on the phase III IMpower133 trial. Another trial has now shown benefit with another similar agent. At the 2019 World Conference on Lung Cancer, Luis Paz-Ares, MD (Hospital Universitario 12 de Octubre, Madrid, Spain), presented results from the randomized phase III CASPIAN trial, evaluating the addition of the PD-L1 inhibitor durvalumab to etoposide and either cisplatin or carboplatin chemotherapy, followed by maintenance durvalumab, in 537 patients with previously untreated extensive-stage SCLC.
Addition of durvalumab to platinum and etoposide chemotherapy resulted in a significant improvement in overall survival (OS) compared to chemotherapy alone. Patients in the durvalumab group had a median OS of 13.0 months, compared to 10.3 months in the chemotherapy alone group (HR 0.73, P=.0047). At 18 months, the estimated OS rate was 33.9% for patients receiving durvalumab plus chemotherapy and 24.7% for patients receiving chemotherapy alone. The estimated 12-month progression-free survival (PFS) rates were 17.5% and 4.7% for durvalumab plus chemotherapy versus chemotherapy alone (HR 0.78).
The adverse event (AE) profile was consistent with the known safety profile of durvalumab. Rates of grade 3/4 AEs were similar between the two groups (61.5% vs 62.4%), and serious AEs were less frequent in patients receiving durvalumab (30.9% vs 36.1%). Immune-mediated AEs occurred in 19.6% of patients receiving durvalumab plus chemotherapy, compared to 2.6% of patients receiving chemotherapy alone.
The investigators concluded that the addition of durvalumab to chemotherapy for first-line treatment of patients with extensive-stage SCLC results in a clinically meaningful improvement in OS, corresponding to a 27% reduction in the risk of death. Futhermore, these results confirm the benefit of PD-L1 inhibitors in first-line treatment, supporting outcomes seen in the IMpower133 trial.
Read more about this study on Medscape News.