EGFR-TKIs plus stereotactic body radiation therapy (SBRT) for stage IV Non-small cell lung cancer (NSCLC): A prospective, multicenter, randomized, controlled phase II study

Abstract

Background: Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have a significant therapeutic effect in the treatment of advanced non-small-cell lung cancer (NSCLC) with EGFR mutations. However, the acquired resistance greatly limits the survival benefit of EGFR-TKIs for EGFR-mutant NSCLC patients. We aimed to assess the efficacy and safety of stereotactic body radiotherapy (SBRT) plus EGFR-TKIs in these patients.

Methods: In this prospective, randomized, controlled, phase 2 study, participants were recruited from 4 different hospitals in Wuhan, China. Eligible patients were histologically confirmed to have NSCLC with an EGFR-sensitive mutation (19DEL or 21L858R) and diagnosed at stage IV. Patients who had received first-line EGFR-TKIs treatment including gefitinib, erlotinib, and icotinib and achieved stable disease or partial response were enrolled after three months. Eligible participants were randomly assigned (1:1) to receive SBRT plus EGFR-TKIs or EGFR-TKIs treatment alone. In the combination-group, different tumor sites were irradiated at doses ranging from 30-50 Gy in five fractions. Considering the short duration of SBRT, the TKIs were continued during the radiotherapy. The primary endpoint was progression-free survival (PFS), and the secondary endpoints were overall survival (OS) and safety. This study was registered at ClinicalTrials.gov, with the registration number of NCT03595644.

Results: Between May 4, 2018 and Dec 20, 2019, 74 patients were screened, of whom 62 patients were enrolled and randomized. The study was closed early with 62/72 patients due to slow accrual. The enrolled patients were randomly assigned to receive SBRT plus EGFR-TKI(n = 31) or EGFR-TKI alone (n = 31). One patient who was randomized to the SBRT plus EGFR-TKI group refused to receive SBRT during the treatment, and, 61 patients were included the modified intention-to-treat (mITT) analysis, with 30 in the SBRT plus EGFR-TKI and 31 in the EGFR-TKI group. As of the clinical cutoff date (Feb 14, 2022), the median follow-up was 29.4 months (IQR 6.9-38.9). The median PFS of the EGFR-TKI group and SBRT combination group was 9.0 vs 17.6 months (hazard ratio [HR] = 0.52, 95% confidence interval [95%CI], 0.31-0.89, P = 0.016). Meanwhile, the median OS was 23.2 vs 33.6 months (HR [95%CI], 0.53(0.30-0.95); P = 0.026). There was no grade 3 or greater toxicity observed in either group, the grade 2 adverse events were 50% in the EGFR-TKIs + SBRT group while the percentage was 45.2% in the EGFR-TKIs group.

Conclusions: The addition of SBRT significantly delayed the onset of acquired resistance to EGFR-TKIs and prolonged the PFS and OS of patients. Radiotherapy of the primary lesion alone might be superior to metastatic sites. Further confirmatory studies are needed to confirm our findings.

Keywords: Drug resistance; EGFR-TKI; NSCLC; SBRT.