Characterizing the Efficacy and Safety of Chemotherapy Plus Everolimus in HER2-Negative Metastatic Breast Cancer Harboring Altered PI3K/AKT/mTOR

BACKGROUND

The clinical outcomes of chemotherapy (CT) for the treatment of metastatic triple-negative (TN) and hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (mBC) have proven to be disappointing. The phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway, a tumor-promoting signaling cascade frequently mutated in breast cancer (BC), has been implicated in chemoresistance. In this study, our objective is to investigate the efficacy and safety of combining everolimus with chemotherapy in mBC patients exhibiting mutations in the PI3K/AKT/mTOR pathway.

METHODS

We conducted a retrospective analysis to characterize the efficacy, safety, and their association with clinical and molecular characteristics of metastatic lesions in 14 patients with HER2- mBC. These patients harbored at least one altered member of the PI3K/AKT/mTOR signaling pathway and were treated with a combination of a chemotherapy agent and the mTOR inhibitor everolimus (CT+EVE).

RESULTS

The majority of patients belonged to the triple-negative (TN) subtype (9/14, 64.3%), having already undergone 2 lines of chemotherapy (CT) in the metastatic setting (11, 78.6%). These patients carried altered phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) and were administered a vinorelbine-containing regimen (10, 71.4%). The objective response rate (ORR) was 42.9%, with a disease control rate of 92.9%. The median progression-free survival (PFS) and overall survival (OS) were 5.9 (95% confidence interval (CI): 4.9-13.6) months and 14.3 (95% CI: 8.5-not reached (NR)) months, respectively. Patients with fewer prior treatment lines tended to exhibit longer PFS. OS, PFS, and ORR were comparable between hormone receptor-positive (HR+) and triple-negative breast cancer (TNBC) patients, but numerical improvements were noted in patients with a single PI3K pathway alteration compared to those with more than one alteration. Genomic alterations that surfaced upon progression on CT+EVE included cyclin dependent kinase 4 (CDK4) and epidermal growth factor receptor (EGFR) amplification, as well as neurofibromin 1 (NF1) mutation, suggesting potential mechanisms of acquired resistance. An analysis of adverse events indicated manageable toxicities.

CONCLUSIONS

The findings of this study suggest both activity and safety for the combination of chemotherapy and the mTOR inhibitor everolimus (CT+EVE) in patients with HER2- mBC who have alterations in the PI3K pathway, particularly those who have received fewer prior chemotherapy. However, it is crucial to note that large-scale, randomized control studies are warranted to more comprehensively characterize the efficacy and safety of this combination therapy.

Treatment Patterns and Health Outcomes among Patients with HER2 IHC0/-Low Metastatic or Recurrent Breast Cancer

Improved understanding of the biological heterogeneity of breast cancer (BC) has facilitated the development of more effective and personalized approaches to treatment. This study describes real-world evidence on treatment patterns and outcomes for a population-based cohort of patients with human epidermal growth factor receptor (HER2) IHC0 and -low BC with de novo or recurrent disease from Alberta, Canada. Patients 18+ years old diagnosed with HER2 IHC0/-low, de novo/recurrent BC from 2010 to 2019 were identified using Alberta's cancer registry. Analyses of these patients' existing electronic medical records and administrative claims data were conducted to examine patient characteristics, treatment patterns, and survival outcomes. A total of 3413 patients were included in the study, of which 72.10% initiated first line hormonal and non-hormonal systemic therapy. The 1-year overall survival (OS) was 81.09% [95% CI, 79.52-82.69]. Recurrent patients had a higher OS compared to de novo patients: 54.30 months [95% CI, 47.80-61.90] vs. 31.5 months [95% CI, 28.40-35.90], respectively. Median OS was 43.4 months [95% CI, 40.70-47.10] and 35.80 months [95% CI, 29.00-41.70] among patients with HER2-low and HER2 IHC0 cancer, respectively. The study results provide real-world evidence regarding the clinical outcomes of HER2 IHC0/-low and de novo/recurrent disease.

Clinical Outcomes of HER2-Negative Metastatic Breast Cancer Patients in Italy in the Last Decade: Results of the GIM 13-AMBRA Study

GIM 13-AMBRA is a longitudinal cohort study aimed at describing therapeutic strategies and the relative outcome parameters in 939 HER2-ve MBC patients. Taxanes-based regimens, or taxanes + targeted agents, mainly Bevacizumab, were the preferred first choice in both Luminal (30.2%) and TNBC (33.3%) patients. The median PFS1 was 12.5 months (95% CI 16.79-19.64), without any significant difference according to subtypes, while the median Time to first Treatment Change (TTC1) was significantly lower in TNBC patients (7.7 months-95% CI 5.7-9.2) in comparison to Luminal A (13.2 months, 95% CI 11.7-15.1) and Luminal B patients (11.8 months, 95% CI 10.3-12.8). PFS2 was significantly shorter in TNBC patients (5.5 months, 95% CI 4.3-6.5 vs. Luminal A-9.4, 95% CI 8.1-10.7, and Luminal B-7.7 95% CI 6.8-8.2, F-Ratio 4.30, p = 0.014). TTC2 was significantly lower in patients with TNBC than in those with the other two subtypes. The median OS1 was 35.2 months (95% CI 30.8-37.4) for Luminal A patients, which was significantly higher than that for both Luminal B (28.9 months, 95% CI 26.2-31.2) and TNBC (18.5 months, 95% CI 16-20.1, F-ratio 7.44, p = 0.0006). The GIM 13-AMBRA study is one of the largest collections ever published in Italy and provides useful results in terms of time outcomes for first, second, and further lines of treatment in HER2- MBC patients.

Abemaciclib-induced lung damage leading to discontinuation in brain metastases from breast cancer: A case report

BACKGROUND

This case report addresses the dearth of effective therapeutic interventions for central nervous system metastases in patients with HER2-negative breast cancer. It presents a unique case of a woman with estrogen receptor-positive, HER2-negative breast cancer who developed brain metastasis. The report highlights her initial favorable response to abemaciclib and letrozole therapy prior to the discontinuation due to drug-induced lung damage (DILD).

CASE SUMMARY

In this comprehensive case summary, we present the clinical course of a woman in her 60s, who 11 years following primary breast cancer surgery, was diagnosed with multiple brain metastases. As a third-line systemic therapy, she underwent treatment with abemaciclib and letrozole. This treatment approach yielded a near-partial response in her metastatic brain lesions. However, abemaciclib administration ceased due to the emergence of DILD, as confirmed by a computed tomography scan. The DILD improved after 1 mo of cessation. Despite ongoing therapeutic efforts, the patient's condition progressively deteriorated, ultimately resulting in death due to progression of the brain metastases.

CONCLUSION

This case underscores the challenge of managing adverse events in responsive brain metastasis patients, given the scarcity of therapeutic options.

Anti-hormonal maintenance treatment with the CDK4/6 inhibitor ribociclib after 1st line chemotherapy in hormone receptor positive / HER2 negative metastatic breast cancer: A phase II trial (AMICA)

PURPOSE

This phase II study evaluated the impact of adding ribociclib to maintenance endocrine therapy (ET) treatment of physicians' choice following the first palliative chemotherapy in pre- and post-menopausal women with hormone receptor positive (HR+)/human epidermal growth factor 2 negative (HER2-) metastatic breast cancer (mBC).

PATIENTS AND METHODS

The initial randomized study design was later amended into a single-arm study, and all subsequent patients received ribociclib and ET. The primary end point was locally assessed progression-free survival (PFS). Secondary end points included overall survival (OS), clinical benefit rate (CBR), safety, compliance, and quality of life (QoL).

RESULTS

A total of 43 patients received ribociclib + ET and 10 patients received ET only. Median PFS was 12.4 months [95% CI 8.7-24.4] for patients who received ribociclib + ET and 4.75 months [95% CI 1.0-10.3] for those who received ET only. Median OS was not reached for patients who received ribociclib + ET, and 28 (65.1%) patients experienced clinical benefit [95% CI 49.1-79.0]. For patients who received ribociclib + ET, grade 3-4 hematological adverse events (AEs) occurred in 25 (58.1%) patients, and grade 3-4 non-hematological AEs occurred in 17 (39.5%) patients. During the study, 15 patients died - 14 of whom due to tumor-related reasons, and one patient due to pneumonia, which was not treatment-related.

CONCLUSION

The results of the AMICA study show a promising efficacy and safety of maintenance treatment with ribociclib added to ET after at least stable disease following the first metastatic chemotherapy in patients with HR+/HER2-mBC.

TRIAL REGISTRATION

Anti-hormonal Therapy With Ribociclib in HR-positive/HER2- Negative Metastatic Breast Cancer (AMICA), NCT03555877, https://clinicaltrials.gov/ct2/show/NCT03555877.

Impact of the OncotypeDX score and HER2 RNA PCR levels on HER2-low IHC levels in primary and metastasized tumors

PURPOSE

One-half of hormone receptor-positive (HR +) breast cancer (BC) patients have low expression of HER2 (HER2-low) and may benefit from trastuzumab deruxtecan (TDXd). This study aimed to identify parameters associated with HER2-low levels in primary and metastatic tumors. We specifically sought to determine whether OncotypeDX and HER2 mRNA levels could identify patients who would otherwise be considered HER2-negative by immunohistochemistry (IHC).

METHODS

This retrospective analysis of all consecutive HR + patients who underwent OncotypeDX from January 2004 to December 2020 was conducted in a single medical center (n = 1429). We divided HER2-negative cases into HER2-low (IHC = 1 + or 2 + and non-amplified fluorescent situ hybridization) and HER2-0 (IHC = 0). HER2 RT-PCR was evaluated from the OncotypeDX results.

RESULTS

HER2-low cases exhibited significantly higher HER2 RT-PCR scores (p = 2.1e-9), elevated estrogen receptor (ER) levels (p = 0.0114), and larger tumor sizes compared to HER2-0 cases (> 2 cm; 36.6% vs. 22.1%, respectively, p < 0.00001). Primary tumors > 2 cm were more likely to be HER2-low (OR = 2.07, 95% CI: 1.6317 to 2.6475, p < 0.0001). Metastatic BCs expressed higher HER2 IHC scores compared with primary BCs (Wilcoxon signed-rank, p = 0.046). HER2 IHC scores were higher for low-risk vs. medium-risk OncotypeDX (p = 0.0067). No other clinical or pathological parameters were associated with the increase in HER2 levels in the metastatic samples.

CONCLUSION

It might be beneficial to use clinical data from the primary tumor, including the HER2 RT-PCR score, to determine a HER2-low status.

Benefit-risk trade-offs in treatment choice in advanced HER2 negative breast cancer: patient and oncologist perspectives

Objective: To evaluate which treatment attributes US patients and oncologists prioritize in HER2 negative advanced breast cancer (ABC). Methods: Preferences were assessed via a discrete choice experiment. Also, treatment goal statements were rated on an agreement scale. Results: Patients (n = 169) most valued improving overall survival (OS), followed by improving nausea and neuropathy. Oncologists (n = 117) most valued improving OS, followed by neuropathy and progression-free survival. Regarding treatment goals, oncologists (67%) perceived that patients are more focused on efficacy than quality of life; fewer patients (29%) agreed with this statement; 81% of oncologists and 51% of patients agreed that patients prefer oral treatment. Conclusion: Patients and oncologists were willing to accept increases in toxicities in exchange for efficacy improvements in HER2 negative ABC.

Ipatasertib plus paclitaxel for PIK3CA/AKT1/PTEN-altered hormone receptor-positive HER2-negative advanced breast cancer: primary results from cohort B of the IPATunity130 randomized phase 3 trial

PURPOSE

PI3K/AKT pathway alterations are frequent in hormone receptor-positive (HR+) breast cancers. IPATunity130 Cohort B investigated ipatasertib-paclitaxel in PI3K pathway-mutant HR+ unresectable locally advanced/metastatic breast cancer (aBC).

METHODS

Cohort B of the randomized, double-blind, placebo-controlled, phase 3 IPATunity130 trial enrolled patients with HR+ HER2-negative PIK3CA/AKT1/PTEN-altered measurable aBC who were considered inappropriate for endocrine-based therapy (demonstrated insensitivity to endocrine therapy or visceral crisis) and were candidates for taxane monotherapy. Patients with prior chemotherapy for aBC or relapse < 1 year since (neo)adjuvant chemotherapy were ineligible. Patients were randomized 2:1 to ipatasertib (400 mg, days 1-21) or placebo, plus paclitaxel (80 mg/m², days 1, 8, 15), every 28 days until disease progression or unacceptable toxicity. The primary endpoint was investigator-assessed progression-free survival (PFS).

RESULTS

Overall, 146 patients were randomized to ipatasertib-paclitaxel and 76 to placebo-paclitaxel. In both arms, median investigator-assessed PFS was 9.3 months (hazard ratio, 1.00, 95% CI 0.71-1.40) and the objective response rate was 47%. Median paclitaxel duration was 6.9 versus 8.8 months in the ipatasertib-paclitaxel versus placebo-paclitaxel arms, respectively; median ipatasertib/placebo duration was 8.0 versus 9.1 months, respectively. The most common grade ≥ 3 adverse events were diarrhea (12% with ipatasertib-paclitaxel vs 1% with placebo-paclitaxel), neutrophil count decreased (9% vs 7%), neutropenia (8% vs 9%), peripheral neuropathy (7% vs 3%), peripheral sensory neuropathy (3% vs 5%) and hypertension (1% vs 5%).

CONCLUSION

Adding ipatasertib to paclitaxel did not improve efficacy in PIK3CA/AKT1/PTEN-altered HR+ HER2-negative aBC. The ipatasertib-paclitaxel safety profile was consistent with each agent's known adverse effects. Trial registration NCT03337724.

Molecular Prognostic Factors for Distant Metastases in Premenopausal Patients with HR+/HER2- Early Breast Cancer

Molecular factors that drive metastasis in premenopausal patients with hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2−), early breast cancer (EBC) are largely unknown. To identify markers/signatures contributing to metastasis, we analyzed molecular changes in tumors from premenopausal patients who developed metastasis (M1) and who did not (M0). Ninety-seven premenopausal patients with HR+/HER2− EBC were included (M1, n = 48, median distant metastasis-free survival (DMFS): 54 (7–184) months; M0, n = 49, median follow-up: 149 (121–191) months). Gene expression profiling on tumor RNA (Breast Cancer 360^TM panel, Nanostring) was performed, followed by comprehensive bioinformatic and statistical analyses. Significantly enhanced ROR (risk of recurrence) scores and reduced signature scores of PGR (progesterone receptor), claudin-low, and mammary stemness were determined in M1. These differences were significantly associated with shorter DMFS in univariate survival analyses. Gene set enrichment analysis showed an enriched mTORC1 pathway in M1. Moreover, a metastasis signature of 19 differentially expressed genes (DEGs) that were DMFS-related was defined. Multivariate analysis including the four signatures, 19 DEGs, pN, and pT status, identified LRP2, IBSP, and SCUBE2 as independent prognostic factors. We identified prognostic gene signatures and single-gene markers for distant metastasis in premenopausal HR+/HER2− EBC potentially applicable in future clinical practice.

Ribociclib plus fulvestrant in the treatment of breast cancer

INTRODUCTION

Endocrine therapy (ET) is a standard first-line treatment for hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced breast cancer (ABC) Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) have demonstrated significantly improved progression-free survival (PFS) with ET in patients with ABC. Recent reports indicate that the addition of the CDK4/6i ribociclib to ET, including fulvestrant, significantly improves PFS and overall survival (OS).

AREAS COVERED

This review summarizes the efficacy and safety of ribociclib plus fulvestrant in HR+/HER2- ABC and its role in clinical practice. Various post-progression strategies are discussed.

EXPERT OPINION

In MONALEESA-3, ribociclib +fulvestrant significantly improved PFS and OS in postmenopausal patients who received no prior chemotherapy and ≤1 prior line of ET for ABC and benefited many patient subgroups, including those with visceral metastases and ET resistance. The safety of this combination is manageable and consistent with the known safety profile of ribociclib, with myelosuppression being a common and expected toxicity; other relevant toxicities requiring monitoring that occur at a low rate include hepatobiliary toxicity, pneumonitis, and QTc prolongation. There is an important role for CDK4/6i + ET, including ribociclib + fulvestrant, in clinical practice. The optimal position of CDK4/6i in first or subsequent lines of treatment and the optimal post-CDK4/6i progression strategies are not yet elucidated.

A maintained absolute lymphocyte count predicts the overall survival benefit from eribulin therapy, including eribulin re-administration, in HER2-negative advanced breast cancer patients: a single-institutional experience

PURPOSE

Eribulin methylate (eribulin) improved the overall survival (OS) of HER2-negative advanced breast cancer (HER2-ABC) patients; however, the mechanism underlying the OS improvement has not been clarified. Several reports suggest that eribulin promotes antitumor immunity via tumor micro-environment conditioning. Recently, a maintained baseline lymphocyte count was proposed as predictive marker for eribulin therapy in HER2-ABC patients; however, no associations with the OS have been noted. We retrospectively investigated the neutrophil-to-lymphocyte ratio and absolute lymphocyte count (ALC) in HER2-ABC patients receiving eribulin and assessed the utility of eribulin re-administration for further OS improvement.

METHODS

HER2-ABC patients who received eribulin therapy at Shizuoka Cancer Center between November 2011 and December 2018 were retrospectively analyzed.

RESULTS

A total of 144 HER2-ABC (108 estrogen receptor-positive [ER+], 36 ER-) patients were identified, and 32 patients (28 ER+ , 4 ER-) were re-administered with eribulin. In the ER+ subgroup, a multivariate analysis showed that an ALC ≥ 1000/μL and re-administration were significantly associated with the OS (hazard ratio [HR] 0.503; P = 0.034 and HR 0.366; P < 0.0001, respectively), and an ALC ≥ 1000/μL was also identified as the only predictive factor for re-administration (HR 0.329; P = 0.033). In contrast, a multivariate analysis in the ER- subgroup identified no predictive markers.

CONCLUSION

In HER2-ER + ABC patients, ALC was identified as a predictive marker for eribulin therapy, and the re-administration of eribulin is considered a valid therapeutic option for further improvement of the OS.

Endocrine and Targeted Therapy for Hormone-Receptor-Positive, HER2-Negative Advanced Breast Cancer: Insights to Sequencing Treatment and Overcoming Resistance Based on Clinical Trials

Background: Advanced hormone-receptor positive HER2 negative breast cancer is a common and a very heterogeneous disease. Hormone therapy is the main first line treatment of choice, given alone or in combination with other agents that have shown to improve patient outcomes, Nevertheless, treatment remains generally palliative rather than curative. Sequencing of such treatment remains challenging, especially with resurgence of variable resistance patterns. Multiple attempts have been made to overcome resistance and improve patient survival, yet resistance remains not very well understood and metastatic cancer remains a disease with dismal prognosis.

Methods: In this paper, we searched pubmed database as well as local and international meetings for all studies discussing advanced and metastatic hormone-receptor-positive, her2-negative breast cancer, hormonal treatment, resistance to hormonal treatment, mechanism of resistance, and means to overcome such resistance.

Conclusion: There does not exist an optimal treatment sequence for hormone-receptor-positive, her2-negative advanced breast cancer. However, after review of literature, a reasonable approach may be starting with tamoxifen, aromatase inhibitors, or fulvestrant in absence of visceral crisis, in addition to ensuring adequate ovarian function suppression in pre/peri-menopausal women. Aromatase inhibitors and fulvestrant seem to be superior. Resistance to such agents is increasing, mostly attributed to genetic and molecular changes. Multiple modalities are addressed to overcome such resistance including use of CKD4/6 inhibitors, mTOR inhibitors and PI3K inhibitors in addition to other agents under study, all with promising results. CDK4/6 inhibitors work best when used in frontline setting. Finally, treatment of breast cancer remains a growing field, and more studies are to be awaited.

VicTORia: a randomised phase II study to compare vinorelbine in combination with the mTOR inhibitor everolimus versus vinorelbine monotherapy for second-line chemotherapy in advanced HER2-negative breast cancer

PURPOSE

Improving the outcome of patients with HER2-negative metastatic breast cancer experiencing tumour progression following first-line chemotherapy remains an urgent medical need. The purpose of the VicTORia trial was to show superiority of everolimus in combination with vinorelbine versus vinorelbine monotherapy as second-line chemotherapy for patients with advanced HER2 negative breast cancer.

METHODS

In this randomised phase II trial, 133 patients were recruited in 32 centres in Germany. Patients were randomised 1:1 to second-line chemotherapy either with vinorelbine plus everolimus (arm1) or vinorelbine alone (arm2). Primary endpoint was progression-free survival (PFS). Secondary endpoints were PFS rate at 6 months, overall survival (OS), overall response rate (ORR) and safety. Baseline PI3 K mutational status was determined in plasma samples.

RESULTS

Median progression-free survival was not different between arms (arm1 vs. arm2: 4.01 months, 95% CI 2.40-6.09 vs. 4.08, 95% CI 2.80-5.33). PFS rate at 6 months (arm1 vs. arm2: 39.4%, 95% CI 27.6-50.9% vs. 36.6%, 95% CI 24.6-48.6%), median OS (arm1 vs. arm2: 16.3 months, 95% CI 11.4-19.0 vs. 13.8 months, 95% CI 10.2-19.1) and ORR were not different between arms. Most frequent grade 3/4 adverse events were neutropenia (50% vs. 40%), gastrointestinal toxicities (19.1% vs. 6.1%), and infections (19.1% vs. 7.7%). PI3 K mutational status was neither associated with PFS nor with OS.

CONCLUSION

Although well tolerated, the efficacy of everolimus and vinorelbine combination therapy was not superior to vinorelbine monotherapy. There was no correlation between PI3 K mutational status and efficacy. EudracCT No 2011-001024-38, ClinicalTrials.gov No NCT01520103.

Bevacizumab in the neoadjuvant treatment of human epidermal growth factor receptor 2-negative breast cancer: A meta-analysis of randomized controlled trials

Several randomized clinical trials have suggested the effectiveness of bevacizumab (Bev) in early and advanced breast cancer; however, due to the increased toxicity and lack of a clear long-term survival benefit, there is currently no defined role for Bev in breast cancer in the USA, while it has been approved in Europe. We herein sought to conduct a meta-analysis of large randomized trials comparing the efficacy and long-term outcome of neoadjuvant chemotherapy with Bev compared with chemotherapy without Bev in human epidermal factor receptor 2 (HER2)-negative breast cancer. A search was conducted through PubMed and Ovid Medline databases. Among the 279 articles identified, 5 met the eligibility criteria and were included in the present analysis. A total of 2,268 patients treated with Bev and 2,278 treated without Bev were analyzed. Pathological complete response (pCR) was obtained in 35% of patients treated with Bev and in 26% of those treated without Bev. A statistically significant increase (26%) in the incidence of pCR was observed in the Bev-treated group. However, patients treated with Bev exhibited no significant difference in the risk of disease recurrence or death. To the best of our knowledge, this is the first meta-analysis addressing the long-term outcomes of Bev in combination with chemotherapy in the neoadjuvant treatment of HER2-negative breast cancer. The results confirmed the significant benefit of Bev combined with chemotherapy compared with chemotherapy alone on breast cancer response, in both triple-negative and hormone receptor-positive cases. However, this benefit does not translate into a long-term disease-free or definitive overall survival advantage. Optimizing patient selection is desirable for maximizing the long-term benefits of Bev, while reducing cost and treatment-related adverse effects. Future efforts directed toward the discovery of predictive markers would be crucial for identifying the subset(s) of breast cancer patients who are most likely to benefit from Bev therapy.

The role of abemaciclib in treatment of advanced breast cancer

Until recently, the mainstay of treatment in the majority of hormone receptor (HR)-positive, human epidermal growth factor 2 receptor (HER2)-negative advanced breast cancer (ABC) has consisted of single-agent endocrine therapy (ET). However, as understanding of endocrine resistance has grown, newer targeted agents have come to the fore. Inhibition of cyclin-dependent kinase complexes 4 and 6 (CDK4/6) combined with ET has shown significant activity in HR+ HER2- ABC, with impressive results in terms of progression-free survival (PFS) when compared with ET alone. This review summarizes the seminal findings pertaining to CDK4/6 inhibition in this population, specifically focusing on abemaciclib, contrasted with palbociclib and ribociclib. Potential directions for future studies are discussed, as a way of addressing outstanding issues such as establishing optimal treatment sequencing and agent combinations, appropriate patient selection to derive maximal benefits, predictive biomarkers and the employment of CDK4/6 inhibition beyond the ABC setting.

The safety of palbociclib for the treatment of advanced breast cancer

INTRODUCTION

Despite improvements in the diagnosis and management of early stage breast cancer, about one third of the patients still progress to metastatic disease. Most of the patients with metastatic breast cancer have a hormone receptor positive and human epidermal growth factor receptor 2 negative subtype with a median survival of more than 3 years. For these patients, endocrine therapy with its favorable toxicity profile is the current standard of care. However, patients with metastatic breast cancer have an incurable disease. Therefore, not only efficacy but also quality of life are key when selecting a therapy regimen. Areas covered: This paper aims to discuss the efficacy and toxicity profile of the new endocrine-based therapy option palbociclib together with endocrine treatment. Expert opinion: The addition of targeted agents like palbociclib can overcome intrinsic or acquired resistance to endocrine therapy and substantially prolong progression free survival. The combination of palbociclib plus endocrine therapy is associated with a tolerable and well manageable toxicity profile as well as maintenance of quality of life. Thus, addition of palbociclib to endocrine therapy offers a new and important treatment option for hormone receptor positive metastatic breast cancer.

Role of everolimus in the treatment of metastatic HER2-negative/HR-positive breast cancer

Metastatic breast cancer (mBC) is a leading cause of mortality for women around the world. The response to hormonotherapy of the patients with HER2-negative/HR-positive mBC is usually limited, and many strategies are in place to contrast the hormonotherapy resistance. Since efficacy and effectiveness of everolimus have been established by many trials, this review is aimed to give a structured synthesis to define the everolimus clinical role among the treatment options for mBC. Key aspects of everolimus dosing and safety profile, drawn up by relevant findings, are included, as well as the role of biomarkers to identify subgroups of mBC patients who may best benefit from everolimus treatment.

A functional signal profiling test for identifying a subset of HER2-negative breast cancers with abnormally amplified HER2 signaling activity

The results of clinical trials evaluating the efficacy of HER2 inhibitors in patients with breast cancer indicate that the correlation between HER2 receptor levels and patient outcomes is as low as 50%. The relatively weak correlation between HER2 status and response to HER2-targeting drugs suggests that measurement of HER2 signaling activity, rather than absolute HER2 levels, may more accurately diagnose HER2-driven breast cancer. A new diagnostic test, the CELx HER2 Signaling Profile (CELx HSP) test, is demonstrated to measure real-time HER2 signaling function in live primary cells. In the present study, epithelial cells extracted fresh from breast cancer patient tumors classified as HER2 negative (HER2-, n = 34 of which 33 were estrogen receptor positive) and healthy subjects (n = 16) were evaluated along with reference breast cancer cell lines (n = 19). Live cell response to specific HER2 agonists (NRG1b and EGF) and antagonist (pertuzumab) was measured. Of the HER2- breast tumor cell samples tested, 7 of 34 patients (20.5%; 95% CI = 10%-37%) had HER2 signaling activity that was characterized as abnormally high. Amongst the tumor samples there was no correlation between HER2 protein status (by cell cytometry) and HER2 signaling activity (hyperactive or normal) (Regression analysis P = 0.144, R2 = 0.068). One conclusion is that measurement of HER2 signaling activity can identify a subset of breast cancers with normal HER2 receptor levels with abnormally high levels of HER2 signaling. This result constitutes a new subtype of breast cancer that should be considered for treatment with HER2 pathway inhibitors.

Utility of the CPS+EG staging system in hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer treated with neoadjuvant chemotherapy

BACKGROUND

Pathologic complete response after neoadjuvant chemotherapy (NACT) correlates with overall survival (OS) in primary breast cancer. A recently described staging system based on pre-treatment clinical stage (CS), final pathological stage (PS), estrogen receptor (ER) status and nuclear grade (NG) leads to a refined estimation of prognosis in unselected patients. Its performance in luminal type breast cancers has not been determined. This study investigates the clinical utility of this CPS+EG score when restricted to hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) patients and compares the results to a cohort of unselected patients.

METHODS

The CPS+EG score was calculated for 6637 unselected patients and 2454 patients with HR+/HER2- tumours who received anthracycline/taxane-based NACT within 8 prospective German trials.

RESULTS

Five-year disease-free survival (DFS) and OS were 75.6% and 84.1% for the unselected cohort and 80.6% and 87.8% for the HR+/HER2- subgroup, respectively. The CPS+EG system distinguished different prognostic groups with 5-year DFS ranging from 0% to 91%. The CPS+EG system leads to an improved categorisation of patients by outcome compared to CS, PS, ER or NG alone. When applying the CPS+EG score to the HR+/HER2- subgroup, a shift to lower scores was observed compared to the overall population, but 5-year DFS and OS for the individual scores were identical to that observed in the overall population.

CONCLUSIONS

In HR+/HER2- patients, the CPS+EG staging system retains its ability to facilitate a refined stratification of patients according to outcome. It can help to select candidates for post-neoadjuvant clinical trials in luminal breast cancer.

Clinicopathological factors predicting early and late distant recurrence in estrogen receptor-positive, HER2-negative breast cancer

BACKGROUND

Most studies analyzing prognostic factors for late relapse have been performed in postmenopausal women who received tamoxifen or aromatase inhibitors as adjuvant endocrine therapy for estrogen receptor (ER)-positive breast cancer.

METHODS

A total of 223 patients (108 premenopausal and 115 postmenopausal) with early distant recurrence and 149 patients (62 premenopausal and 87 postmenopausal) with late distant recurrence of ER-positive, HER2-negative breast cancer who were given their initial treatment between 2000 and 2004 were registered from nine institutions. For each late recurrence patient, approximately two matched control patients without relapse for more than 10 years were selected. Clinicopathological factors and adjuvant therapies were compared among the three groups by menopausal status and age.

RESULTS

Factors predicting early recurrence in premenopausal women were large tumor size, high lymph node category and high tumor grade, whereas predictors for late recurrence were large tumor size and high lymph node category. In postmenopausal women under 60 years of age, factors predicting early recurrence were bilateral breast cancer, large tumor size, high lymph node category, low PgR expression and high Ki67 labeling index (LI), while predictors for late recurrence were large tumor size and high lymph node category. On the other hand, in postmenopausal women aged 60 years or older, factors predicting early recurrence were bilateral breast cancer, large tumor size, high lymph node category, high tumor grade, low ER expression and high Ki67 LI, whereas predictors for late recurrence were high lymph node category, low ER expression and short duration of adjuvant endocrine therapy.

CONCLUSION

Predictors of early and late distant recurrence might differ according to menopausal status and age.

Treatment of metastatic breast cancer with 𝑛𝑎𝑏-paclitaxel in the community practice setting: a US Oncology survey

BACKGROUND

Different dosages-schedules of nab-paclitaxel have been assessed in trials of metastatic breast cancer (MBC). However, there is limited information on nab-paclitaxel dosing-scheduling in the community setting.

OBJECTIVE

To report on experience with nab-paclitaxel for human epidermal growth factor receptor 2 (HER2)-negative MBC and identify patient characteristics affecting nab-paclitaxel treatment patterns in the community practice setting.

METHODS

From September 6-October 21, 2013, a 35-question, web-based survey on nab-paclitaxel dosing, toxicities leading to dose modifications, management, and treatment duration was sent to US Oncology network oncologists. Respondents were categorized by percentage of their patients with HER2-negative MBC who received nab-paclitaxel.

RESULTS

104 of 428 oncologists responded; 84% were from large practices (≥16 oncologists), and 56% had a high level of experience using nab-paclitaxel. For first- and second-line treatment, 100 mg/m² weekly was the most common starting dosage-schedule, followed by 125 mg/m² weekly and 260 mg/m² every 3 weeks (q3w); 150 mg/m² weekly was used least frequently. Several factors, including select aggressive disease characteristics, were found to affect nab-paclitaxel dose selection. Weekly dosing was preferred in patients with select aggressive disease characteristics, whereas q3w dosing was commonly used in patients aged ≤50 years and those with good performance status. Differences in management styles among oncologists with high compared with infrequent nab-paclitaxel experience were also observed. Peripheral neuropathy and neutropenia were common dose-limiting toxicities.

LIMITATIONS

Recall and response bias may be limitations of this study.

CONCLUSIONS

In the community setting, nab-paclitaxel 100 mg/m² weekly was the most commonly used starting dose for patients with HER2-negative MBC, including those with aggressive disease characteristics.

Long-Term Complete Remission with nab-Paclitaxel, Bevacizumab, and Gemcitabine Combination Therapy in a Patient with Triple-Negative Metastatic Breast Cancer

This is a case study of a 52-year-old female patient diagnosed in June 2007 with primary metastatic invasive ductal carcinoma of the left breast and synchronous metastases in the bone, lymph nodes, and lung. Biopsy results of the tumor tissue were negative for the estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2). In November 2007, she participated in a phase II study of metastatic HER2-negative breast cancer. Treatment consisted of systemic chemotherapy with gemcitabine 1,500 mg/m², nab-paclitaxel 150 mg/m², and bevacizumab 10 mg/kg once every other week. The patient experienced pain relief in her sternum after 5 weeks of chemotherapy, and her analgesic therapy was discontinued. After 7 months, the patient achieved a complete radiographic response, which was maintained for nearly 2 additional years. She continued receiving treatment throughout this period, requiring 1 dose reduction due to fatigue. The patient experienced no other adverse events, including neuropathy, and continued working uninterrupted throughout her treatment. The patient was discontinued from the study in May 2010 after disease progression, almost a full 3 years after diagnosis. The patient showed minimal response to subsequent therapies but had disease stabilization and died from her disease in April 2012. Median overall survival for patients with metastatic triple-negative breast cancer is between 12 and 13.3 months. This patient survived nearly 5 years following diagnosis. This case exemplifies how therapy with nab-paclitaxel, bevacizumab, and gemcitabine may prolong survival, with minimal toxicity, in select patients with triple-negative metastatic breast cancer.