Introduction: Vascular endothelial growth factor promotes an immunosuppressive tumor microenvironment that can be reverted by an antiangiogenic therapy. This two-stage, phase 2 study aimed to determine the treatment efficacy of adding bevacizumab to atezolizumab in patients with metastatic NSCLC whose disease had progressed after atezolizumab monotherapy.
Methods: Immune checkpoint inhibitor-naive patients with NSCLC, without EGFR or ALK alterations, whose disease progressed after at least one line of platinum-based chemotherapy were eligible. The patients received atezolizumab 1200 mg once every 3 weeks until radiographic progression (stage I). Then, bevacizumab 15 mg/kg was combined with atezolizumab 1200 mg once every 3 weeks (stage II). The primary end point was the disease control rate (DCR) confined to stage II.
Results: A total of 42 and 24 patients were enrolled in stages I and II, respectively. Most patients had negative programmed death ligand-1 expression (71.4%) and received one or two lines of therapy (95.2%). In stage I, patients achieved a DCR of 35.7% (95% confidence interval [CI]: 21.6-52.0). In stage II, three (12.5%) and 18 (75.0%) of 24 patients had partial response and stable disease, respectively, leading to a DCR of 87.5% (95% CI: 67.6-97.3). For 24 patients enrolled in stage II, the median progression-free survival was 5.6 (95% CI: 4.1-7.1) months and the overall survival was 14.0 (95% CI: 10.7-17.4) months. Treatment-related adverse events occurred in 25% of the patients in stage II, but all were of grade 1 or 2.
Conclusions: Combination of bevacizumab plus atezolizumab for patients with metastatic NSCLC whose disease had progressed after atezolizumab monotherapy was found to have a promising antitumor activity with good tolerability.
Keywords: Anti-angiogenic therapy; Atezolizumab; Bevacizumab; Immune checkpoint inhibitor; Non–small cell lung cancer.
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