The combination of VEGF inhibitors and anti-oestrogen therapies in breast cancer

Maintenance Therapy with Aromatase Inhibitor in epithelial Ovarian Cancer (MATAO): study protocol of a randomized double-blinded placebo-controlled multi-center phase III Trial

Background

A high percentage of epithelial ovarian cancers (EOC) express the estrogen receptor (ER), which is an ideal target for endocrine therapy. Letrozole is a proven, potent aromatase inhibitor, extensively tested and used in the treatment of ER positive breast cancer. In addition, it seems a potent drug for patients with heavily pre-treated OC as demonstrated in several distinctive settings. However, it has never been evaluated prospectively in a maintenance setting for ovarian cancer after standard of care. The here proposed trial aims to define a population of EOC patients, who would benefit from the effectiveness of the generic agent letrozole, with little expected toxicity and thus beneficial impact on overall quality of life (QoL).

Methods

In this international multicenter randomized, placebo-controlled phase III trial at clinical centers in Switzerland, Germany and Austria, we plan to include 540 patients with primary, newly diagnosed FIGO Stage II to IV and histologically confirmed low- or high-grade serous or endometrioid epithelial ovarian/fallopian tube/peritoneal cancer. Patients are randomized in a 1:1 ratio into two groups: receiving blinded study treatment (letrozole or placebo tablets). When assuming a HR of 0.7, a median PFS of 18 months in the control arm and a median PFS of 25.7 months in the treatment arm, a two-sided alpha level of 5%, 3.5 years recruitment and 1.5 years observation time, we expect 330 events to have occurred within these 5 years in the total cohort yielding a power of 90%. Follow-up data for the whole cohort will be collected for up to 10 years and for the low-grade cancer for up to 12 years.

Discussion

The here proposed randomized phase III trial aims to identify patients with EOC in the maintenance setting, who benefit from the effectiveness of the letrozole, by proving its efficacy whilst maintaining a high standard of QoL due to the limited toxicity expected in comparison to the current alternative drugs on the market for this treatment phase.

Trial registration

This trial is registered at clinicaltrials.gov under the identifier NCT04111978. Registered 02 October 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09555-8.

Antiangiogenic effects of melatonin in endothelial cell cultures

Endothelial cells represent one of the critical cellular elements in tumor microenvironment playing a crucial role in the growth and progression of cancer through controlling angiogenesis. Vascular endothelial growth factor (VEGF) produced from tumor cells is essential for the expansion of breast cancer and may function in both paracrine and autocrine manners to promote proliferation, growth, survival and migration of endothelial cells. Since melatonin regulates tumor microenvironment by decreasing the secretion of VEGF by malignant epithelial cells and also regulates VEGF expression in human breast cancer cells, the aim of the present study was to investigate the anti-angiogenic activity of melatonin against the pro-angiogenic effects of breast cancer cells. In this work, we demonstrate that melatonin strongly inhibited the proliferation as well as invasion/migration of human umbilical vein endothelial cells (HUVECs). Melatonin disrupted tube formation and counteracted the VEGF-stimulated tubular network formation by HUVEC. In addition, conditioned media collected from human breast cancer cells were angiogenically active and stimulated tubule length formation and this effect was significantly counteracted by the addition of anti-VEGF or melatonin. Melatonin also disintegrated preformed capillary network. All these findings demonstrate that melatonin may play a role in the paracrine interactions that take place between malignant epithelial cells and proximal endothelial cells. Melatonin could be important in reducing endothelial cell proliferation, invasion, migration and tube formation, through a downregulatory action on VEGF. Taken together, our findings suggest that melatonin could potentially be beneficial as an antiangiogenic agent in breast cancer with possible future clinical applications.