Abstract 32P
Background
SCLC transformation is one of the acquired resistance mechanisms for epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in EGFR mutation-positive non-small cell lung cancer (NSCLC) patients. It remains unclear whether the addition of atezolizumab to chemotherapy could prolong PFS and OS of patients with SCLC transformation after EGFR-TKI treatment.
Methods
Three groups of advanced lung adenocarcinoma patients who relapsed after EGFR-TKI were analyzed in this retrospective study: cohort A included patients who did not undergo SCLC transformation and received atezolizumab plus chemotherapy after EGFR-TKI; cohort B included patients with SCLC transformation and following atezolizumab treatment; cohort C included patients who underwent SCLC transformation and did not receive atezolizumab treatment.
Results
Twenty-six patients were enrolled in this research (cohort A: N = 6; cohort B: N = 6; cohort C: N = 14). Five of six patients in group A and all patients of group B received atezolizumab plus albumin paclitaxel-based regimens. In addition, five of six patients received atezolizumab plus albumin paclitaxel-based regimens after conventional etoposide/platinum treatment. Etoposide/platinum +/− EGFR-TKI regimens were given to all patients in group C as first-line treatment after SCLC transformation. DCR (83.3% vs 100.0%, p = 0.224) and ORR (0% vs 16.7%, p = 0.224) were similar between cohort A and cohort B. Comparable median PFS (3.5 m vs 4.7 m, p = 0.086), median OS from diagnosis of advanced stage lung cancer (33.7 m vs 54.3 m, p = 0.077), and median OS from atezolizumab implementation (6.7 vs 7.6 m, p = 0.627) were observed between group A and group B. No significant differences in median PFS between group B and group C (4.7 m vs 3.5 m, p = 0.754). Patients in cohort B presented a tendency to have better median OS from diagnosis of stage IV lung cancer (45.4 m vs 22.5 m, p = 0.180) and better median OS from SCLC transformation (24.1 m vs 11.5 m, p = 0.092) compared with cohort C.
Conclusions
In patients with SCLC transformation after EGFR-TKI, atezolizumab plus albumin paclitaxel-based regimen was a treatment choice after conventional etoposide/platinum regimens.
Legal entity responsible for the study
Y. Wang.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.