Immunotherapy Timing Does Not Significantly Affect Outcomes in ES-SCLC

The timing of immunotherapy initiation does not play a major role in survival outcomes in patients with extensive-stage small cell lung cancer (ES-SCLC), new research has found.1 The findings, which were presented in a poster session at the American Society of Clinical Oncology 2025 Annual Meeting in Chicago, showed patients who received immunotherapy alongside their first cycle of chemotherapy had similar progression-free survival (PFS) to those who received immunotherapy after their first chemotherapy cycle.

Previous research has indicated that the timing of chemotherapy initiation is associated with patient outcomes in SCLC, study author Paresh Kumar, MBBS, of Indiana University, and colleagues, explained. Specifically, a 2020 study based on patients in the National Cancer Database found that shorter time to chemotherapy initiation was associated with worse overall survival (OS) in patients with SCLC.2 

The timing of initiation to immunotherapy, either with the first cycle of chemotherapy or within 21 days of diagnosis, does not significantly affect outcomes in ES-SCLC. | Image Credit: Bonsales - stock.adobe.com

Kumar and colleagues noted there is currently no clear evidence about the relative importance of immunotherapy treatment timing for patients with ES-SCLC.1 Thus, they conducted an analysis of patients who sought care at Indiana University Health and its IU Simon Comprehensive Cancer Center to see whether patient outcomes might correlate with immunotherapy initiation timing.

The investigators analyzed 149 patient charts, representing people diagnosed with ES-SCLC between January 2018 and August 2024. Of those, 75 patients were identified who received chemotherapy and either atezolizumab (Tecentriq; Genentech) or durvalumab (Imfinzi; AstraZeneca). The cohort of patients had a median age of 62.7 years, and most (64%) were female. Seventeen patients had an Eastern Cooperative Oncology Group Performance Status of 2 or above, and 19 patients had brain metastases.

The investigators stratified patients based on whether they began immunotherapy along with their first cycle of chemotherapy or after it. They also stratified patients based on the total time to immune checkpoint inhibitor initiation, using a cutoff of 21 days.

The entire cohort of patients had a median OS of 12.2 months, and a median PFS of 5 months. Patients who received immunotherapy within 21 days had a median OS of 16.8 months, while those who began immunotherapy more than 21 days after diagnosis had a median OS of 11.8 months (P = .26). Results for patients receiving immunotherapy during or after their first cycle of chemotherapy were similar. Those who had immunotherapy along with their first chemotherapy cycle (n = 42) had a median OS of 16 months; those who initiated immunotherapy later (n = 33) had a median OS of 10 months (P = .43). However, Kumar and colleagues noted that the median PFS was similar between the groups.

The investigators used the median OS for the cohort (12.2 months) to define responders and nonresponders. Responders (n = 30) had an OS of 12.2 months or longer, while nonresponders had an OS of less than 12.2 months. Among responders, 60% received immunotherapy during their first cycle of chemotherapy, while 53.3% of nonresponders received immunotherapy during their first chemotherapy cycle.

“The timing of initiation to immunotherapy, either with the first cycle of chemotherapy or within 21 days of diagnosis, does not significantly improve outcomes in patients diagnosed with ES-SCLC,” Kumar and colleagues concluded.

Still, the investigators noted there is still room for additional study on the question of timing. In particular, they explained that most of the patients in their analysis (81.3%) received atezolizumab. Yet, they said recent real-world data “suggests a survival benefit with use of durvalumab.” Thus, further research is warranted that analyzes both timing and immunotherapy selection as possible factors in patient outcomes.

References

1. Kumar P, He W, Karkash A, et al. Does early versus late initiation of immunotherapy in extensive-stage small cell lung cancer affect survival outcomes? Presented at: ASCO 2025; May 30-June 3, 2025; Chicago, Illinois. Abstract 8099.

2. Bhandari S, Kumar R, Pham D, Gaskins J, Kloecker G. Treatment timing in small cell lung cancer, a National Cancer Database analysis. Am J Clin Oncol. 2020;43(5):362-365. doi:10.1097/COC.0000000000000676