Evaluating the Impact of Bevacizumab Maintenance Therapy on Overall Survival in Advanced Non-Small-Cell Lung Cancer

Patients with advanced-stage non small-cell lung cancer with the nonsquamous histology who receive bevacizumab with their initial chemotherapy may achieve additional benefit with bevacizumab maintenance therapy. Observational data were collected and used to evaluate this hypothesis. Various forms of statistical analysis were applied to adjust for the selection bias that is inherent with observational data. Bevacizumab maintenance therapy did prolong overall survival and should be considered in patients with advanced-stage non small-cell lung cancer with the nonsquamous histology. Background: In patients with advanced-stage non small-cell lung cancer (NSCLC) with nonsquannous histology, bevacizumab maintenance therapy after initial combination with platinum-based chemotherapy has been approved in the United States and Europe. In this study, a comparative effectiveness analysis of bevacizumab maintenance therapy after initial chemotherapy with bevacizumab is described. Methods: A retrospective analysis of patients treated in 17 community oncology practices across the United States was conducted. Inclusion criteria consisted of patients with stage IIIb or IV disease who received bevacizumab maintenance after an initial first-line induction regimen. Overall survival (OS) was evaluated by using the method of Kaplan-Meier and Cox proportional hazard modeling. To control for selection bias that is inherent in observational studies, an 18-week landmark and propensity score analysis was conducted. The hazard ratio (HR) for OS was then evaluated in a sensitivity analysis. Results: A total of 272 patients with advanced-stage NSCLC met the inclusion criteria. Only 74 (27.2%) patients received bevacizumab maintenance therapy. Patients in the bevacizumab maintenance group tended to be younger and fitter, with a more favorable disease profile, which resulted in an improvement in the crude unadjusted OS (23.1 vs. 10.3 months; hazard ratio (HR) 0.44 [95% CI, 0.32-0.59]). Landmark and propensity score analyses supported the finding of a reduced risk of death with bevacizunnab maintenance therapy (HR 0.52 [95% CI, 0.37-0.73] for landmark analyses and HR 0.70 [95% CI, 0.39-1.28] for propensity score analyses). Conclusions: Bevacizumab maintenance therapy contributed to an OS benefit in this retrospective sample of patients with NSCLC, even after multiple statistical adjustments for selection bias. Clinical Lung Cancer, Vol. 14, No. 2, 120-7 (c) 2013 Elsevier Inc. All rights reserved.