520P - Role of atezolizumab in controlling CNS progression in ES-SCLC

Background

Adding atezolizumab to the established etoposide and carboplatin chemotherapy (AECb) for extensive-stage small cell lung cancer (ES-SCLC) is now standard, following success of Impower 133 trial. Controlling central nervous system (CNS) progression is pivotal for patients’ survival and quality of life. We explored a role of atezolizumab in controlling brain metastasis in ES-SCLC patients.

Methods

A total of 156 patients, diagnosed with ES-SCLC and received 1^st line chemotherapy between August 2016 and July 2022 at Korea University Guro Hospital, were included. Survival data, comprising progression-free survival (PFS), overall survival (OS), time to intracranial progression (TTicP, with deaths censored) and brain PFS, were evaluated.

Results

During the study period, 79 (50.6%) patients underwent chemotherapy without atezolizumab, while 77 (49.4%) patients received AECb as their initial treatment. The median follow-up duration was 23.8 months, and there were no discernible differences between two groups in terms of age, sex and primary metastatic sites. Patients in the AECb group exhibited improved CNS outcomes: 27 (34.2%) and 16 (20.8%) patients experienced intracranial progression, with 24 (30.4%) and 14 (18.2%) cases of new brain metastasis. Both TTicP (median: 14.6 months vs. not reached; 12-month TTicP rate: 65.4% vs. 84.4%, P = 0.003) and brain PFS (median: 8.2 vs. 11.7 months; 12-month brain PFS rate 30.2% vs. 48.6%, P = 0.001) were significantly prolonged in the AECb group. These findings remained consistent even after adjusting for age, initial metastatic site, and prophylactic cranial irradiation (PCI). As expected, the AECb group demonstrated favorable survival outcomes, marked by improved PFS (median: 4.4 vs. 4.6 months, P = 0.004) and OS (median: 10.2 vs. 12.6 months, P = 0.001).

Conclusions

The addition of atezolizumab to conventional chemotherapy not only enhances patients’ survival but also improves intracranial disease control, thereby extending the duration of time to intra-cranial progression. This is first real-world data supporting benefits of atezolizumab in controlling intracranial progression in SCLC patients.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.