Impact of Baseline and On-Treatment Glycemia on Everolimus-Exemestane Efficacy in Patients with Hormone Receptor-Positive Advanced Breast Cancer (EVERMET).

PURPOSE: The mTOR complex C1 (mTORC1) inhibitor everolimus in combination with the aromatase inhibitor exemestane is an effective treatment for patients with hormone receptor-positive (HR+), HER2-negative (HER2-), advanced breast cancer (HR+/HER2- aBC). However, everolimus can cause hyperglycemia and hyperinsulinemia, which could reactivate the PI3K/protein kinase B (AKT)/mTORC1 pathway and induce tumor resistance to everolimus. EXPERIMENTAL DESIGN: We conducted a multicenter, retrospective, Italian study to investigate the impact of baseline and on-treatment (i.e., during first 3 months of therapy) blood glucose levels on progression-free survival (PFS) in patients with HR+/HER2- aBC treated with everolimus-exemestane. RESULTS: We evaluated 809 patients with HR+/HER2- aBC treated with everolimus-exemestane as any line of therapy for advanced disease. When evaluated as dichotomous variables, baseline and on-treatment glycemia were not significantly associated with PFS. However, when blood glucose concentration was evaluated as a continuous variable, a multivariable model accounting for clinically relevant patient- and tumor-related variables revealed that both baseline and on-treatment glycemia are associated with PFS, and this association is largely attributable to their interaction. In particular, patients who are normoglycemic at baseline and experience on-treatment diabetes have lower PFS compared with patients who are already hyperglycemic at baseline and experience diabetes during everolimus-exemestane therapy (median PFS, 6.34 vs. 10.32 months; HR, 1.76; 95% confidence interval, 1.15-2.69; P = 0.008). CONCLUSIONS: The impact of on-treatment glycemia on the efficacy of everolimus-exemestane therapy in patients with HR+/HER2- aBC depends on baseline glycemia. This study lays the foundations for investigating novel therapeutic approaches to target the glucose/insulin axis in combination with PI3K/AKT/mTORC1 inhibitors in patients with HR+/HER2- aBC.

Antitumor activity and efficacy of shorter versus longer duration of anthracycline-taxane neoadjuvant chemotherapy in stage II-III HER2-negative breast cancer: a 10-year, retrospective analysis.

BACKGROUND: Neoadjuvant anthracycline-taxane-based chemotherapy (ChT) is a standard of care treatment option for stage II-III breast cancer (BC) patients. However, the optimal duration of neoadjuvant ChT has been poorly investigated so far. MATERIAL AND METHODS: We retrospectively retrieved clinical data of patients with stage II-III human epidermal growth factor receptor 2-negative (HER2-) BC who were treated between October 2007 and January 2018 with neoadjuvant AT (doxorubicin-paclitaxel) for three cycles followed by CMF (cyclophosphamide-methotrexate-5-fluorouracil) for three cycles (cohort A) or with four AT cycles followed by four CMF cycles (cohort B). The aim of our study was to investigate the impact of neoadjuvant ChT duration (cohort A versus cohort B) on pathological complete response (pCR) rates, disease-free survival (DFS) and overall survival (OS). RESULTS: Of 209 HER2- BC patients included, 62 had triple-negative breast cancer (TNBC) and 147 had hormone receptor-positive (HR+) BC. Median age was 48 years (range 30-74 years). A total of 111 patients belonged to cohort A and 98 patients belonged to cohort B. pCR was detected in 29 (13.9%) patients, 25 (40.3%) of whom had TNBC and four (2.7%) had HR+ HER2- BC. Patients achieving pCR had significantly longer DFS and OS, with statistical significance reached only in patients with TNBC. We found no differences between cohort A and cohort B in terms of pCR rates (15.3% versus 12.2%; p = 0.55), DFS (p = 0.49) or OS (p = 0.94). The incidence of grade 3/4 adverse events was similar in cohort A versus cohort B as well (22.5% versus 19.4%; p = 0.54). CONCLUSION: Shorter duration of neoadjuvant anthracycline-taxane ChT was not associated with worse clinical outcomes in patients with stage II-III BC. Prospective studies are needed to evaluate whether the duration of neoadjuvant anthracycline-taxane-based ChT can be reduced in specific patient subgroups without negatively affecting clinical outcomes.

Palbociclib added to ongoing endocrine therapy for hormone receptor-positive HER2-negative metastatic breast cancer: A case report series.

Palbociclib is a potent cyclin-dependent kinase (CDK)4/6 inhibitor that disrupts cell cycle progression and has been recently approved in combination with an aromatase inhibitor or fulvestrant as first- and second-line treatment in hormone receptor (HR)+, human epidermal growth factor receptor (HER)2- metastatic breast cancer. There is evidence that palbociclib may reverse endocrine therapy resistance and that it may also be added to ongoing endocrine therapy beyond progression to obtain clinical benefit. The aim of the present study was to explore this possibility in 5 patients who received palbociclib + fulvestrant following disease progression while under treatment with fulvestrant alone. The median progression-free survival was not reached during a median follow-up of 25 months, and the most frequent best response was stable disease. Three patients remained under treatment on the last re-evaluation. All patients had highly endocrine-sensitive disease and had previously received fulvestrant for ≥12 months. The hypothesis that a selected subpopulation of patients with HR+/HER2- metastatic breast cancer may benefit from the addition of palbociclib to ongoing endocrine therapy beyond disease progression merits further investigation.

Everolimus versus alpelisib in advanced hormone receptor-positive HER2-negative breast cancer: targeting different nodes of the PI3K/AKT/mTORC1 pathway with different clinical implications.

BACKGROUND: The PI3K/AKT/mTORC1 axis is implicated in hormone receptor-positive HER2-negative metastatic breast cancer (HR+ HER2- mBC) resistance to anti-estrogen treatments. Based on results of the BOLERO-2 trial, the mTORC1 inhibitor everolimus in combination with the steroidal aromatase inhibitor (AI) exemestane has become a standard treatment for patients with HR+ HER2- mBC resistant to prior non-steroidal AI therapy. In the recent SOLAR-1 trial, the inhibitor of the PI3K alpha subunit (p110α) alpelisib in combination with fulvestrant prolonged progression-free survival (PFS) when compared to fulvestrant alone in patients with PIK3CA-mutated HR+ HER2- mBC that progressed after/on previous AI treatment. Therefore, two different molecules targeting the PI3K/AKT/mTORC1 axis, namely everolimus and alpelisib, are available for patients progressing on/after previous AI treatment, but it is unclear how to optimize their use in the clinical practice. Here, we reviewed the available clinical evidence deriving from the BOLERO-2 and SOLAR-1 trials to compare efficacy and safety profiles of everolimus and alpelisib in advanced HR+ HER2- BC treatment. Adding either compound to standard endocrine therapy provided similar absolute and relative PFS advantage. In the SOLAR-1 trial, a 76% incidence of grade (G) 3 or 4 (G3/G4) adverse events was reported, while G3/G4 toxicities occurred in 42% of patients in the BOLERO-2 trial. While alpelisib was only effective in patients with PIK3CA-mutated neoplasms, retrospective analyses indicate that everolimus improves exemestane efficacy independently of PIK3CA mutational status. CONCLUSIONS: Based on the available efficacy and safety data, the "new" alpelisib may be burdened by higher incidence of severe adverse events, higher costs, and anticancer efficacy that is limited to PIK3CA-mutated tumors when compared to the "old" everolimus. Therefore, the everolimus-exemestane combination remains an effective and reasonably well-tolerated therapeutic option for HR+ HER2- mBC patients progressing after/on previous AI treatment, independently of PIK3CA mutational status.

CDK 4/6 Inhibitors as Single Agent in Advanced Solid Tumors.

Cyclin-dependent kinases (CDK) 4/6 inhibitors, namely abemaciclib, palbociclib, and ribociclib, interfere with cell cycle progression, induce cell senescence and might promote cancer cell disruption by a cytotoxic T cells-mediated effect. Phase III randomized clinical trials have proven that CDK4/6 inhibitors (CDK4/6i) in combination with several endocrine agents improve treatment efficacy over endocrine agents alone for hormone receptor positive (HR+) HER2 negative (HER2-) metastatic breast cancer (MBC). Based on such results, these combinations have been approved for clinical use. Preclinical studies in cell cultures and mouse models proved that CDK4/6i are active against a broad spectrum of solid tumors other than breast cancer, including liposarcoma, rhabdomyosarcoma, non-small cell lung cancer, glioblastoma multiforme, esophageal cancer, and melanoma. The role of CDK4/6i in monotherapy in several solid tumors is currently under evaluation in phase I, II, and III trials. Nowadays, abemaciclib is the only of the three inhibitors that has received approval as single agent therapy for pretreated HR+ HER2- MBC. Here we review biological, preclinical and clinical data on the role of CDK4/6 inhibitors as single agents in advanced solid tumors.