Abstract: Purpose: We determined if intermittent first-line treatment with paclitaxel plus bevacizumab was not inferior to continuous treatment in patients with HER2-negative, advanced breast cancer. Methods: Patients were randomized to 2 × 4 cycles or continuous 8 cycles of paclitaxel plus bevacizumab, followed by bevacizumab maintenance treatment until disease progression or unacceptable toxicity. The primary endpoint was overall progression-free survival (PFS). A proportional-hazards regression model was used to estimate the HR. The upper limit of the two-sided 95% CI for the HR was compared with the non-inferiority margin of 1.34. Results: A total of 420 patients were included with well-balanced characteristics. In the intention-to-treat analysis, median overall PFS was 7.4 months (95% CI 6.4–10.0) for intermittent and 9.7 months (95% CI 8.9–10.3) for continuous treatment, with a stratified HR of 1.17 (95% CI 0.88–1.57). Median OS was 17.5 months (95% CI 15.4–21.7) versus 20.9 months (95% CI 17.8–24.0) for intermittent versus continuous treatment, with a HR of 1.38 (95% CI 1.00-1.91). Safety results and actually delivered treatments revealed longer durations of treatment in the continuous arm, without significant unexpected findings. Conclusion: Intermittent first-line treatment cannot be recommended in patients with HER2-negative advanced breast cancer. Clinical trial registration: EudraCT 2010-021519-18; BOOG 2010-02.

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doi.org/10.1007/s10549-018-4906-8, hdl.handle.net/1765/109962
Breast Cancer Research and Treatment
Department of Medical Oncology

Claessens, A.K.M. (Anouk K. M.), Bos, M.E.M.M. (Monique E. M. M.), Lopez-Yurda, M. (Marta), Bouma, J.M. (Jeanette M.), Rademaker-Lakhai, J.M. (Jeany M.), Honkoop, A. H., … Erdkamp, F. (2018). Intermittent versus continuous first-line treatment for HER2-negative metastatic breast cancer: the Stop & Go study of the Dutch Breast Cancer Research Group (BOOG). Breast Cancer Research and Treatment. doi:10.1007/s10549-018-4906-8