Overall Survival Benefit With Lapatinib in Combination With Trastuzumab for Patients With Human Epidermal Growth Factor Receptor 2-Positive Metastatic Breast Cancer: Final Results From the EGF104900 Study
Phase III EGF104900 data demonstrated that lapatinib plus trastuzumab significantly improved progression-free survival (PFS) and clinical benefit rate versus lapatinib monotherapy, offering a chemotherapy-free option for patients with heavily pretreated human epidermal growth factor receptor 2 (HER2) -positive metastatic breast cancer (MBC). Final planned overall survival (OS) analysis from EGF104900 is reported here.
Patients with HER2-positive MBC whose disease progressed during prior trastuzumab-based therapies were randomly assigned to receive lapatinib monotherapy or lapatinib in combination with trastuzumab. OS and updated PFS data are presented using Kaplan-Meier curves and log-rank tests stratified for hormone receptor and visceral disease status. Subgroup analyses were conducted to identify characteristics of patients deriving the greatest clinical benefit.
In this updated final analysis of all patients randomly assigned with strata (n = 291), lapatinib plus trastuzumab continued to show superiority to lapatinib monotherapy in PFS (hazard ratio [HR], 0.74; 95% CI, 0.58 to 0.94; P = .011) and offered significant OS benefit (HR, 0.74; 95% CI, 0.57 to 0.97; P = .026). Improvements in absolute OS rates were 10% at 6 months and 15% at 12 months in the combination arm compared with the monotherapy arm. Multiple baseline factors, including Eastern Cooperative Oncology Group performance status of 0, nonvisceral disease, < three metastatic sites, and less time from initial diagnosis until random assignment, were associated with improved OS. Incidence of adverse events was consistent with previously reported rates.
These data demonstrated a significant 4.5-month median OS advantage with the lapatinib and trastuzumab combination and support dual HER2 blockade in patients with heavily pretreated HER2-positive MBC.
"This downstream activation leads to induction of genes that promote oncogenic transformation via cell survival, proliferation, angiogenesis and metastasis . For women with HER2 over-expressing breast tumors, anti-HER2 directed therapy has become a treatment platform with numerous FDA approved therapies including trastuzumab, pertuzumab and lapatinib  . While HER2 over-expression was initially associated with the most guarded prognosis in breast cancer (BrCa), the advent of a targeted anti- HER2 therapy, has resulted in women with these HER2 positive tumors having one of the most favorable prognoses . "
"In the advanced setting, the dual blockade with trastuzumab and pertuzumab without chemotherapy produced considerable response rate and clinical benefit even in patients with HR positive tumors  . The combination of trastuzumab and lapatinib showed significantly longer PFS and OS compared to lapatinib alone in trastuzumab-refractory patients, half of them with HR positive tumors  . However, in the Cleopatra trial patients with HER-2 positive and HR positive tumors had reduced benefit in PFS and OS from dual blockade with pertuzumab and trastuzumab compared to patients with HR negative tumors, as a confirmation of a possible negative interference between HER-2 blocking agents and endocrine pathway  . "
[Show abstract][Hide abstract] ABSTRACT: Breast cancer is a heterogeneous disease, and within the HER-2 positive subtype this is highly exemplified by the presence of substantial phenotypical and clinical heterogeneity, mostly related to hormonal receptor’s (HR) expression. It is well known how HER-2 positivity is commonly associated with a more aggressive tumor phenotype and decrease overall survival and, moreover, with a reduced benefit from endocrine treatment. Preclinical studies corroborate the role played by functional crosstalks between HER-2 and estrogen receptor (ER) signaling in endocrine resistance and, more recently, the activation of ER signaling is emerging as a possible mechanism of resistance to HER-2 blocking agents. Indeed, HER-2 positive breast cancer heterogeneity has been suggested to underlie the variability of response not only to endocrine treatments, but also to HER-2 blocking agents. Among HER-2 positive tumors, HR status probably defines two distinct sutypes, with dissimilar clinical behaviour and different sensitivity to anticancer agents. The triple positive subtype, namely, ER/PgR/Her-2 positive tumors, could be considered the subset which most closely resembles the HER-2 negative/HR positive tumors, with substantial differences in biology and clinical outcome. We argue on whether in this subgroup the “standard” treatment may be considered, in selected cases, i.e., small tumors, low tumor burden, high expression of both hormonal receptors, an overtreatment. This article review the existing literature on biologic and clinical data concerning the HER-2/ER/PgR positive tumors, in an attempt to better define the HER-2 subtypes and to optimize the use of HER-2 targeted agents, chemotherapy and endocrine treatments in the various subsets.
Cancer Treatment Reviews 12/2014; 41(2). DOI:10.1016/j.ctrv.2014.12.005 · 7.59 Impact Factor
"Large tumours can be genetically diverse and therefore it is possible that a small part of cells within the tumour can be resistant to the drug and will survive therapy and continue to grow (Bozic et al. 2013). Several strategies have been suggested to overcome resistance to HER2-targeted therapy in order to block by-pass mechanism or induce synergistic effect between anti-cancer agents (Blackwell et al. 2012; Mohd Sharial et al. 2012; Xia et al. 2002). It has been proposed that the use of combined therapy of two agents from the beginning of cancer treatment gives more hope for cure compared to the traditional sequential approach (Blair et al. 2014; Bozic et al. 2013). "
[Show abstract][Hide abstract] ABSTRACT: Background
The lichen compound (+)-protolichesterinic acid (+)-PA, isolated from Iceland moss, has anti-proliferative effects on several cancer cell lines. The chemical structure of (+)-PA is similar to a known fatty acid synthase (FASN) inhibitor C75.
To test whether the anti-proliferative activity of (+)-PA is associated with effects on FASN and HER2 (human epidermal growth factor receptor 2) and major signalling pathways. Synergism between (+)-PA and lapatinib, a HER2 active drug, was also evaluated.
Materials and methods
Pure compound was isolated by preparative high-performance liquid chromatography (HPLC) and purity of (+)-PA analyzed by analytical HPLC. Cell viability was assessed using Crystal violet staining. FASN and HER2 expression was estimated by immunofluorescence. The Meso Scale Discovery (MSD)® assay was used to measure activation of ERK1/2 and AKT. Synergism was estimated by the CalcuSyn software.
Treatment with (+)-PA increased FASN expression in SK-BR-3 cells, which overexpress FASN and HER2, implying a compensatory response to inhibition of FASN activity. HER2 expression was decreased suggesting secondary downregulation. ERK1/2 and AKT signalling pathways were inhibited, probably due to reduced levels of HER2. No effects were observed in T-47D cells. Synergism between (+)-PA and lapatinib was observed in the SK-BR-3 cells.
Results suggest that the primary effect of (+)-PA is inhibition of FASN activity. Synergistic effects with lapatinib were seen only in SK-BR-3 cells, and not T-47D cells, further supporting the notion that (+)-PA acts by inhibiting FASN with secondary effects on HER2 expression and signalling. (+)-PA could therefore be a suitable agent for further testing, alone or in combination treatment against HER2-overexpressing breast cancer.
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