Six or More Cycles of Chemo Prolong Survival With Atezolizumab in ES-SCLC

Subgroup analysis showed that, of patients with LS-SCLC, men, patients 65 years or younger, and those without liver metastasis who received 6 or more cycles of induction chemotherapy had improved survival outcomes.

Undergoing 6 or more cycles of induction chemotherapy led to significantly prolonged progression-free survival (PFS) and overall survival (OS), enhancing the efficacy of first-line atezolizumab (Tecentriq) combined with chemotherapy in patients with extensive-stage small cell lung cancer (ES-SCLC), according to results from a retrospective analysis published in Translational Lung Cancer Research.

Among patients receiving first-line immunotherapy, with a median follow-up time of 39.1 months (95% CI, 26.5-not attained [NA]), the median PFS was 7.0 months (95% CI, 6.0-9.0), and the median overall survival was 17.6 months (95% CI, 15.9-18.9). Additionally, the overall response rate (ORR) was 86.7%, and the disease control rate was 97.8%; 4 patients (8.9%) experienced a complete response, 35 patients (77.8%) experienced a partial response, 5 patients (11.1%) had stable disease, and 1 patient (2.2%) had progressive disease.

For patients who received 6 or more cycles of induction chemotherapy (n = 25), the median PFS was 8.0 months (95% CI, 7.0-15.0) vs 5.0 months (95% CI, 3.0-9.0) for patients who received fewer than 6 cycles (P = .002); the median OS was 18.5 months (95% CI, 18.0-NA) vs 13.1 months (95% CI, 9.2-18.9), respectively (P < .001).

Further subgroup analyses using the Cox proportional hazard regression model showed that receipt of more than 6 cycles of induction chemotherapy had significantly improved survival outcomes. Notable subgroups this improvement was observed in included men (HR, 0.24; 95% CI, 0.11-0.55; P <.001), patients 65 years or younger (HR, 0.30; 95% CI, 0.13-0.71; P = .006), those without liver metastasis (HR, 0.33; 95% CI, 0.17-0.66; P = .002), those with or without brain metastasis (with = HR, 0.23, 95% CI, 0.06-0.90; P = .04; without = HR, 0.41; 95% CI, 0.19-0.89; P = .03), those without bone metastasis (HR, 0.22; 95% CI, 0.09-0.53; P <.001), and those without brain radiotherapy (95% CI, 0.44; 95% CI, 0.22-0.90; P = .02).

On the other hand, in women (HR, 0.61; 95% CI, 0.18-2.06; P = .42), patients older than 65 years (HR, 0.38; 95% CI, 0.13-1.12; P = .08), those with bone metastasis (HR, 0.66; 95% CI, 0.23-1.90; P = .45), and those without cross-line immunotherapy (HR, 0.44; 95% CI, 0.18-1.07; P = .07), the risk of death was reduced in the group receiving 6 or more cycles, although the difference was not statistically significant compared to the group receiving fewer than 6 cycles.

“In first-line immunochemotherapy for ES-SCLC, patients who received [6 or more] cycles of induction chemotherapy had longer PFS and OS than those who received fewer cycles,” senior study author Puyuan Xing, of the Department of Medical Oncology in the National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital at the Chinese Academy of Medical Sciences and Peking Union Medical College in Beijing, and coauthors wrote in the paper. “Moreover, this survival benefit was evident across most subgroups, highlighting the potential of extending induction chemotherapy as a clinical strategy for improving treatment outcomes in ES-SCLC.”

A total of 45 patients were included in the retrospective analysis. Eligible patients were treated at 5 tertiary medical centers in China from March 2020 to September 2022. All patients were required to have a pathologically confirmed diagnosis of SCLC, extensive-stage disease at diagnosis according to the Veterans Administration Lung Study Group staging system, receipt of first-line systemic treatment with atezolizumab combined with chemotherapy, an induction chemotherapy regimen consisting of etoposide plus platinum, and completion of at least 2 cycles of induction chemotherapy as first-line treatment.

All patients received atezolizumab with etoposide and platinum in a first-line setting; platinum-based agents were nedaplatin in 1 patient, cisplatin in 6, and carboplatin in the rest. Additionally, 4 patients received 3 cycles, 9 patients received 4 cycles, 7 patients received 5 cycles, 1 patient received 8 cycles, and the rest received 6 cycles. The authors noted that 62.2% of patients underwent maintenance therapy with atezolizumab after first-line chemotherapy, and 44.4% of patients received second-line immunotherapy after first-line treatment failed.

The study end points were PFS and OS in the overall population, as well as in subpopulations based on the number of induction chemotherapy cycles received.

Of the 45 patients, 20.0% experienced an immune-related adverse event; they were rash (n = 3), hypothyroidism (n = 2), immune-related pneumonia (n = 3), and immune-related encephalitis (n = 1). No adverse events were grade 4 or fatal.

Reference

You M, Liu J, Teng F, et al. Effect of the number of induction chemotherapy cycles on the efficacy of first-line atezolizumab combined with chemotherapy in extensive-stage small cell lung cancer. Transl Lung Cancer Res. 2025;14(4):1408-1417. doi:10.21037/tlcr-2025-207