Immunomodulatory effects of metronomic vinorelbine (mVRL), with or without metronomic capecitabine (mCAPE), in hormone receptor positive (HR+)/HER2-negative metastatic breast cancer (MBC) patients: final results of the exploratory phase 2 Victor-5 study.

Tregs are able of suppressing tumor-specific effector cells, such as lymphocytes CD8+, CD4+ and Natural Killer cells. Different drugs, especially different schedules of administration, like metronomic chemotherapy (mCHT), seem to be able to increase anticancer immunity, by acting on downregulation of Tregs. Most of the data available regarding the immunomodulating effect of mCHT have been obtained with Cyclophosphamide (CTX). Aim of the present study was to explore the effects of mVRL and mCAPE administration, alone or in combination, on T cells. Observation of 13 metastatic breast cancer patients lasted controlling for 56 days, where Treg frequencies and function, spontaneous anti-tumor T-cell responses were monitored, as well as the clinical outcome. No depletion in Treg absolute numbers, or percentage of T lymphocytes, was observed. Only in 5 patients, a modest and transient depletion of Tregs was observed during the first 14 days of treatment. To better describe the effect on Tregs, we subsequently looked at the variations in Memory, Naïve and Activated Treg subpopulations: we observed a trend in reduction for memory Treg (Treg MEM) and an increase for Treg Naïve (Treg NAIVE) and Treg Activated (Treg ACT) components. We finally analyzed the average trend of Treg in the Treg depleted patients and non-depleted ones, without fiding any significant differences. The trend of the Treg MEM appeared different, showing a reduction during the first 14 days, followed by an increase at the levels before treatment at Day 56 in the group of depleted patients and a progressive substantial reduction in the group of non-depleted patients along the entire course of treatment. Opposed to the data known, treatment with mVRL w/o mCAPE did not show any effect on Tregs.

Metronomic Chemotherapy in Triple-Negative Metastatic Breast Cancer: The Future Is Now?

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.

Metronomic chemotherapy with oral vinorelbine (mVNR) and capecitabine (mCAPE) in advanced HER2-negative breast cancer patients: is it a way to optimize disease control? Final results of the VICTOR-2 study.

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.