Metronomic chemotherapy combined with endocrine therapy: are we challenging some dogmas?

INTRODUCTION

Metronomic chemotherapy exerts its effects via inhibition of angiogenesis, immune modulation of the tumoral stroma, induction of senescence and apoptosis of tumor cells. Due to its favorable toxicity profile and its oral administration, metronomic chemotherapy arises as a promising alternative to be combined with endocrine therapy for the treatment of patients with luminal breast cancer.

AREAS COVERED

The present manuscript reviews the rationale supporting the combination of metronomic chemotherapy and endocrine therapy, discussing the studies that evaluated this regimen in the treatment of early-stage and metastatic breast cancer patients. Finally, we conclude by providing an expert opinion on the current role and perspectives for the combination of metronomic chemotherapy and endocrine therapy in the management of patients with luminal breast cancer.

EXPERT OPINION

Retrospective series and early-phase clinical trials have shown promising signs of activity and a favorable toxicity profile with this regimen, which warrants further investigation as a treatment option for luminal breast cancer patients.

Rationally Designed Ruthenium Complexes for Breast Cancer Therapy

Since the discovery of the anticancer potential of ruthenium-based complexes, several species were reported as promising candidates for the treatment of breast cancer, which accounts for the greatest number of new cases in women every year worldwide. Among these ruthenium complexes, species containing bioactive ligand(s) have attracted increasing attention due to their potential multitargeting properties, leading to anticancer drug candidates with a broader range of cellular targets/modes of action. This review of the literature aims at providing an overview of the rationally designed ruthenium-based complexes that have been reported to date for which ligands were carefully selected for the treatment of hormone receptor positive breast cancers (estrogen receptor (ER+) or progesterone receptor (PR+)). In addition, this brief survey highlights some of the most successful examples of ruthenium complexes reported for the treatment of triple negative breast cancer (TNBC), a highly aggressive type of cancer, regardless of if their ligands are known to have the ability to achieve a specific biological function.

Capecitabine-Based Chemoendocrine Combination as First-Line Treatment for Metastatic Hormone-Positive Metastatic Breast Cancer: Phase 2 Study

BACKGROUND

Preclinical studies have suggested a synergistic effect of tamoxifen and capecitabine in estrogen receptor-positive cell lines. We evaluated the safety and efficacy of first-line chemoendocrine treatment in patients with metastatic breast cancer. Biochemical assessment was performed of serum levels of thymidine phosphorylase enzyme (TP), serum tamoxifen, hydroxytamoxifen, and 5-fluorouracil in relationship to efficacy.

PATIENTS AND METHODS

This prospective phase 2 interventional study studied patients with estrogen receptor-positive, HER2^- metastatic breast cancer who received either tamoxifen/capecitabine or letrozole/capecitabine as first-line treatment. The dose of capecitabine provided at 2000 mg per day continuously as a fixed dose.

RESULTS

Forty women with a median age of 49.3 years were enrolled. For the whole study group, median progression-free survival (PFS) was 10 months and median overall survival (OS) was 23.3 months. The overall response rate was 60% and the clinical benefit rate 82.5%. Progesterone receptor positivity was associated with significantly longer PFS (12 vs. 7 months, P = .021). The most frequent adverse events were palmar-plantar erythrodysesthesia (62.5%), fatigue (62.5%), diarrhea (30%), abdominal pain (12.5%), and constipation (10%). Changes in serum level of TP were not correlated to response to treatment, PFS, or OS. Higher serum levels of tamoxifen and hydroxytamoxifen were correlated with higher response rates and longer PFS but not OS.

CONCLUSION

Chemoendocrine treatment is well tolerated, with no evidence of contradictory effects between the combination components. However, the efficacy data need more validation.

Organoruthenium(II) Complexes Bearing an Aromatase Inhibitor: Synthesis, Characterization, in Vitro Biological Activity and in Vivo Toxicity in Zebrafish Embryos

Third-generation aromatase inhibitors such as anastrozole (ATZ) and letrozole (LTZ) are widely used to treat estrogen receptor-positive ER+ breast cancers in postmenopausal women. Investigating their ability to coordinate metals could lead to the emergence of a new category of anticancer drug candidates with a broader spectrum of pharmacological activities. In this study, a series of ruthenium (II) arene complexes bearing the aromatase inhibitor anastrozole was synthesized and characterized. Among these complexes, [Ru(η ⁶ -C₆H₆)(PPh₃)(η ¹ -ATZ)Cl]BPh₄ (3) was found to be the most stable in cell culture media, to lead to the highest cellular uptake and in vitro cytotoxicity in two ER+ human breast cancer cell lines (MCF7 and T47D), and to induce a decrease in aromatase activity in H295R cells. Exposure of zebrafish embryos to complex 3 (12.5 μM) did not lead to noticeable signs of toxicity over 96 h, making it a suitable candidate for further in vivo investigations.