Metronomic chemotherapy combined with bevacizumab and erlotinib in patients with metastatic HER2-negative breast cancer: clinical and biological activity.

UNLABELLED: The aim of this study was to determine the safety and efficacy of metronomic chemotherapy combined with targeted drugs in patients with metastatic breast cancer (MBC). We included 26 untreated patients with HER2-negative (HER-) MBC and poor hormone receptor expression. The analysis of the results suggests that the metronomic chemotherapy combined with bevacizumab and erlotinib is effective and well tolerated. BACKGROUND: The object of this study was to evaluate the safety and efficacy of metronomic chemotherapy in combination with bevacizumab and erlotinib in patients with HER2-negative (HER2(-)) metastatic breast cancer (MBC) and poor hormone receptor expression. PATIENTS AND METHODS: Patients with untreated MBC were candidates to receive metronomic oral capecitabine (500 mg thrice daily) and cyclophosphamide (50 mg daily) plus bevacizumab (15 mg/kg every 3 weeks) and erlotinib (100 mg daily). RESULTS: Of 24 patients assessable for response, we observed 1 complete response (CR, 4%), 14 partial responses (58%), 5 patients with stable disease greater than 9 weeks' duration (SD, 21%), and 1 patient (4%) with early progression of disease. The overall clinical benefit (CB) (CR + partial response + SD > 24 weeks) was 75% (95% confidence interval [CI], 53%-90%). Median time to progression was 43 weeks (95% CI, 21-69). Patients with low levels of circulating endothelial progenitors (CEPs) at baseline had a significantly improved progression-free survival (PFS). Toxicity was generally mild. Grade 3 toxicity included diarrhea (n = 1), thrombosis (n = 1), and hypertension (n = 2). Grade 2 adverse events included diarrhea (n = 5), hand-foot syndrome (n = 13), and hypertension (n = 4). CONCLUSION: Treatment with metronomic chemotherapy in combination with bevacizumab and erlotinib was effective in HER2(-), estrogen receptor (ER)- and progesterone receptor (PR)-poor advanced breast cancer.

Increased mean corpuscular volume of red blood cells predicts response to metronomic capecitabine and cyclophosphamide in combination with bevacizumab.

BACKGROUND: There is an urgent need for the identification of commonly assessable predictive factors in the treatment of patients with metastatic breast cancer. METHODS: During the course of a treatment including low dose metronomic oral cyclophosphamide and capecitabine plus i.v. bevacizumab (plus erlotinib in one third of the patients) for metastatic breast cancer, we observed that a relevant number of patients developed repeatedly elevated levels of mean corpuscular volume (MCV) of red blood cells without a significant fall in hemoglobin levels. We conducted a retrospective analysis on these 69 patients to evaluate if the increase in MCV could be associated to tumor response. RESULTS: During the course of treatment 42 out of 69 patients (61%) developed macrocytosis. Using Cox proportional hazards modeling that incorporated macrocytosis (MCV ≥ 100 fl) as a time-dependent covariate, macrocytosis resulted in a halved risk of disease progression (HR 0.45; 95% CI, 0.22-0.92, p-value 0.028). In a landmark analysis limited to patients with no sign of progression after 24 weeks of treatment, median time to progression was 72 weeks (48 weeks after landmark) in patients who had developed macrocytosis, and 43 weeks (19 weeks after landmark) in patients who had not (p=0.023). CONCLUSION: Macrocytosis inversely related to risk of disease progression in patients treated with metronomic capecitabine plus cyclophosphamide and bevacizumab for metastatic breast cancer. This finding may be explained through thymidylate synthase inhibition by capecitabine. Whether bevacizumab has a role in determining macrocytosis, similarly to what happens with sunitinib, has to be further investigated. If other studies will confirm our findings, macrocytosis might be used as an early marker of response during metronomic treatment with capecitabine and cyclophosphamide with or without bevacizumab.

Clustering of endocytic organelles in parental and drug-resistant myeloid leukaemia cell lines lacking centrosomally organised microtubule arrays.

Spatial organisation and trafficking of endocytic organelles in mammalian cells is tightly regulated and dependent on cytoskeletal networks. The dynamics of endocytic pathways is modified in a number of diseases, including cancer, and notably in multidrug resistant (MDR) cells that are refractory to the effects of several anti-cancer agents. These cells often upregulate expression of drug-efflux pumps but this may be synergistic with alternative resistance mechanisms including increased acidification of endocytic organelles that enhances vesicular sequestration of weak-base anti-cancer drugs such as daunorubicin away from their nuclear target. Here, we characterised the distribution of sequestered daunorubicin in commonly used leukaemia cell lines, HL-60, K562, KG1a and the multidrug resistant HL-60/ADR line, and related this to the spatial distribution of their endocytic organelles and microtubule networks. HL-60 and KG1a cells contained microtubule arrays emanating from organising centres, and their endocytic organelles and daunorubicin labelled vesicles were scattered throughout the cytoplasm. HL-60/ADR and K562 cells showed extensive clustering of early and recycling endosomes, late endosomes, lysosomes and daunorubicin to a juxtanuclear region but these cells lacked microtubule arrays. Microtubular organisation within these clustered regions was however, required for spatial tethering of endocytic organelles and the Golgi, as treatment with nocodazole and paclitaxel had major effects on their distribution. HL-60 and HL-60/ADR cells had similar lysosomal pH of <5.0 and overall these findings suggests a general relationship between the absence of microtubule arrays and the propensity of leukaemia cell lines to cluster endocytic organelles and daunorubicin into the juxtanuclear region.