Efficacy of Moxifloxacin plus Treatment of Physician's Choice in Patients with Metastatic Breast Cancer.

Lessons Learned: Moxifloxacin plus continuation of the previous treatment of physician's choice shows promising efficacy in patients with metastatic breast cancer.The addition of moxifloxacin shows well‐tolerated toxicities. Background: Recent studies have confirmed bacterial infection as an important contributor in cancer. Elimination of tumor‐associated microbes may lead to a reduction in tumors and improved survival. Moxifloxacin is an orally administrated fourth‐generation quinolone with broad‐spectrum coverage against tumor‐associated bacteria. Methods: In this study, we assessed the efficacy and safety of moxifloxacin in combination with treatment of physician's choice (TPC) in patients with metastatic breast cancer (MBC). In this single‐arm, phase II study, we recruited 30 patients with MBC who had a trend toward disease progression (stable disease [SD] with increased tumor size) during TPC before enrollment at Sun Yat‐sen University Cancer Center between January 1 and July 30, 2018. Eligible patients were given moxifloxacin once daily at a dose of 400 mg from days 1 to 7 of a 28‐day cycle, in addition to continuing to receive the therapy previously selected by their physicians. Tumor response was determined according to RECIST (version 1.1). Progression‐free survival (PFS) was calculated using the Kaplan‐Meier method. Results: The concomitant use of moxifloxacin and previous TPC yielded a median PFS of 6.6 months (95% confidence interval [CI]: 4.0–9.1) and a 1‐year PFS of 25.9% (95% CI: 10.0%–41.9%). Objective responses were achieved in seven (23.3%, 95% CI: 7.3%–39.4%) patients. The clinical benefit rate was 46.7% (95% CI: 27.7%–65.6%). No grade 4 adverse events (AEs) and four grade 3 AEs were observed, none of which were considered to have definite relation to moxifloxacin. Conclusion: The combination of moxifloxacin with previous TPC shows promising efficacy and well‐tolerated toxicities in patients with MBC. [ABSTRACT FROM AUTHOR]