CHICAGO – Bevacizumab maintenance after first-line chemotherapy for advanced non–small cell lung cancer was associated with longer overall survival in a retrospective study of 403 patients who were treated in outpatient community settings.
Median NSCLC disease progression was 10.3 months among patients who continued on bevacizumab (Avastin) until disease progression after they received first-line chemotherapy plus bevacizumab, compared with 6.5 months for those who discontinued the monoclonal antibody after chemotherapy.
Median overall survival reached 20.9 months vs. 10.2 months, respectively, Dr. Eric Nadler reported in a poster at the Chicago Multidisciplinary Symposium in Thoracic Oncology.
Although it is standard practice in clinical trials to continue bevacizumab until disease progression, recent assessments of treatment patterns in the United States have shown that bevacizumab is often discontinued when chemotherapy ends. Price has been an issue, with the typical monthly cost of bevacizumab for advanced lung cancer placed at about $8,800 in 2006. Only 38% (or 154) of the 403 patients in the study received bevacizumab until disease progression.
The industry-sponsored study identified patients with nonsquamous NSCLC from an electronic health records system that contains data from 884 community-based oncologists in US Oncology Inc.–affiliated practices or clinics in 20 states.
Patients were treated from July 2006 through June 2008, with 31% located in the Southwest and 30% in the Southeast. In all, 37% of patients had private insurance, 57% were covered by Medicare, and 6% had some other payer.
The maintenance group tended to have better pre- and postchemotherapy performance status scores and a greater number of completed chemotherapy cycles (median, six vs. four). Overall, 56% of the maintenance group and 39% of the no-maintenance group received a second-line therapy.
To control for survivorship and selection bias, researchers excluded patients with disease progression or death within 30 days of chemotherapy completion; landmark analyses were conducted at 18, 21, and 26 weeks from initial treatment.
Among those who were alive and progression free at 18 weeks, bevacizumab monotherapy until disease progression was associated with a 46% reduced risk of death (hazard ratio, 0.54), reported Dr. Nadler of the Texas Oncology–Baylor Sammons Cancer Center in Dallas. The association between bevacizumab and longer residual overall survival persisted among patients who remained progression free and alive at 21 weeks (HR, 0.58) and 26 weeks (HR, 0.61).
Bevacizumab monotherapy was associated with longer progression-free survival at 18 weeks (HR, 0.73), but the association was no longer observed at 21 weeks (HR, 0.82) and 26 weeks (HR, 0.79).
Although the nonrandomized nature of the study precludes making any conclusions about causality, the authors concluded that the findings provide "significant insights into real-world patterns of care and associated outcomes and provide important evidence on which to base future comparative effectiveness research."
In a separate national survey of oncologists, Dr. Nadler and associates at Tufts University in Boston reported that 84% of oncologists say that patients’ out-of-pocket spending influences treatment recommendations, even though only 43% frequently or always discuss costs with patients. Among the 787 oncologists surveyed, 79% favored more comparative effectiveness research and 80% supported more cost-effectiveness data, but only 42% felt well prepared to interpret it (Health Aff. [Millwood] 2010;29:196-202).
Genentech supported the study. Dr. Nadler reported no conflicts of interest. Three coauthors reported employment with Genentech and ownership interest in Roche Holdings.