ABSTRACT
Triple-negative breast cancer (TNBC) shows a very bad prognosis, even in early stages of disease. Metronomic chemotherapy refers to the minimum biologically effective dose of a chemotherapy agent given as a continuous dosing regimen with no prolonged drug-free breaks that leads to antitumor activity. In the present article, we review preclinical and clinical data of metronomic administration of chemotherapy agents with or without biological agents in TNBC cell lines and patients, contextually reporting data from the VICTOR-2 study in the subgroup of patients with TNBC, in order to stimulate new ideas for the design of clinical trials in this subset of patients.
ABSTRACT
PURPOSE: The VICTOR-1 study demonstrated that the all-oral metronomic combination of vinorelbine and capecitabine is highly active and well tolerated in hormone receptor-positive/HER2-negative patients. The VICTOR-2 study was designed to confirm these results. METHODS: Patients received mVNR 40 mg three times a week and mCAPE 500 mg three times a day, continuously. The primary endpoint was the clinical benefit rate (CBR); secondary endpoints were toxicity, objective response rate (ORR), and progression-free survival (PFS). RESULTS: Eighty patients were evaluable for the primary efficacy analysis. Median age was 65.3 years; most patients had HR-positive tumors (65 %). The CBR was 45.7 % (95 % CI 28.8-63.4) and 51.1 % (95 % CI 35.8-66.3) in first- and ≥ second-line therapy, respectively. The ORR was 35.5 % in first-line (95 % CI 19.2-54.6) and 25.6 % in ≥second-line (95 % CI 13.5-41.2). The median duration of response was 11.3 and 6.4 months and PFS rates at 1 year were 24.3 and 22.2 %, respectively. In triple-negative breast cancer patients (N = 28, 35 %) a lower, but clinically relevant CBR (35.7, 95 % CI 18.6-55.9) was observed. The main toxicities per cycle were non-febrile neutropenia (1.1 %), hand-foot syndrome (1.0 %), nausea and vomiting (1.0 %), leucopenia (0.8 %), fatigue (0.7 %), and diarrhea (0.4 %). CONCLUSION: The VICTOR-2 study confirms the clinical activity of mVNR and mCAPE in HER2-negative breast cancer patients, suggesting that the easy schedule of administration, which requires monthly blood tests and limits patients' dependence on hospitals, and the low cost of the drugs are valuable elements, even for countries with limited access to innovative or expensive drugs.
