Phase II study of gemcitabine and bevacizumab as first-line treatment in taxane-pretreated, HER2-negative, locally recurrent or metastatic breast cancer.

Background: In first-line treatment of metastatic breast cancer, the best use of the available therapeutic agents is unclear. This study evaluated the efficacy and safety of combined therapy with bevacizumab and gemcitabine.

Patients: Women who were to undergo first-line treatment for locoregionally recurrent or metastatic breast cancer were eligible. Patients must have received a taxane-containing regimen in the neoadjuvant and/or adjuvant setting with a ≥ 12-month disease-free interval.

Methods: This was a single-arm, phase II trial. On day 1 of each 14-day cycle, patients received gemcitabine (2500 mg/m(2)) followed by bevacizumab (10 mg/kg). Patients were treated until complete response, progressive disease (PD), or intolerable toxicity. The primary endpoint was progression-free survival (PFS).

Results: Fifty-two women were enrolled and treated. The median PFS was 4.8 months (95% confidence interval [CI], 3.4-7.6), the 1-year overall survival rate was 68.7% (95% CI, 54.1%-79.5%), and the response rate was 21.4% (95% CI, 10.3%-36.8%). The clinical benefit rate was 35.7%. The median PFS in the triple-negative (n = 19) and non-triple-negative (n = 33) subsets was 3.9 months (95% CI, 2.7-11.7) and 4.9 months (95% CI, 3.4-8.1), respectively. The most common (all grades) drug-related adverse events (AEs) were nausea (51.9%), fatigue (46.2%), decreased appetite (25.0%), and anemia (25.0%). The most common grade 3 or grade 4 drug-related AEs were neutropenia (13.5%), leukopenia (11.5%), and hypertension (7.7%).

Conclusion: Although the gemcitabine-bevacizumab doublet appears active, the median PFS was lower than expected. There were no unexpected safety signals at this dose and schedule of this combination.