Outcomes of women with early-stage breast cancer receiving adjuvant trastuzumab

Effectiveness of Trastuzumab for Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer in a Real-Life Setting: One Decade of Experience Under National Treatment Coverage Regulations

PURPOSE

Trastuzumab has shown an overall survival (OS) benefit in patients with human epidermal growth factor receptor 2 (HER2)–positive breast cancer (BC), in both the adjuvant and the metastatic setting. We assessed the effectiveness of trastuzumab in patients treated in daily practice according to national treatment coverage protocols and compared our results with those reported by randomized clinical trials. These coverage protocols included patient selection criteria similar to those of those clinical trials and were developed by the Uruguayan National Resource Fund (FNR), the agency that has funded these prescriptions for more than a decade.

PATIENTS AND METHODS

We included all patients with HER2-positive BC treated with trastuzumab under FNR coverage approved between January 1, 2006, and December 31, 2016. The source of data was the FNR database, and primary outcome was OS, analyzed through Cox proportional hazards regression analysis.

RESULTS

A total of 1,944 women were included: 1,085 women (55.8%) were postmenopausal and 1,240 (63.7%) had HER2 and hormone receptor–positive BC. Trastuzumab was administered as adjuvant therapy to 1,233 patients (63.5%), of whom 154 also received it as a neoadjuvant treatment. Three hundred nineteen patients (16.4%) received trastuzumab for advanced disease. Five-year OS in the adjuvant setting was 86.4% (95% CI, 84.0% to 88.7%). The median survival of patients with advanced BC was 25.1 months (95% CI, 10.1 to 42.5 months).

CONCLUSION

Our survival results are not inferior to those reported in clinical trials, in both adjuvant and advanced settings. Importantly, these results support the relevance and the feasibility of treating patients in routine practice, following coverage protocols based on patient selection criteria and methods supported by positive clinical trials. In addition, these results favor quality and appropriate access to BC treatment in our country.

Inter-Metastatic Heterogeneity of Tumor Marker Expression and Microenvironment Architecture in a Preclinical Cancer Model

BACKGROUND

Preclinical drug development studies rarely consider the impact of a candidate drug on established metastatic disease. This may explain why agents that are successful in subcutaneous and even orthotopic preclinical models often fail to demonstrate efficacy in clinical trials. It is reasonable to anticipate that sites of metastasis will be phenotypically unique, as each tumor will have evolved heterogeneously with respect to gene expression as well as the associated phenotypic outcome of that expression. The objective for the studies described here was to gain an understanding of the tumor heterogeneity that exists in established metastatic disease and use this information to define a preclinical model that is more predictive of treatment outcome when testing novel drug candidates clinically.

METHODS

Female NCr nude mice were inoculated with fluorescent (mKate), Her2/neu-positive human breast cancer cells (JIMT-mKate), either in the mammary fat pad (orthotopic; OT) to replicate a primary tumor, or directly into the left ventricle (intracardiac; IC), where cells eventually localize in multiple sites to create a model of established metastasis. Tumor development was monitored by in vivo fluorescence imaging (IVFI). Subsequently, animals were sacrificed, and tumor tissues were isolated and imaged ex vivo. Tumors within organ tissues were further analyzed via multiplex immunohistochemistry (mIHC) for Her2/neu expression, blood vessels (CD31), as well as a nuclear marker (Hoechst) and fluorescence (mKate) expressed by the tumor cells.

RESULTS

Following IC injection, JIMT-1mKate cells consistently formed tumors in the lung, liver, brain, kidney, ovaries, and adrenal glands. Disseminated tumors were highly variable when assessing vessel density (CD31) and tumor marker expression (mkate, Her2/neu). Interestingly, tumors which developed within an organ did not adopt a vessel microarchitecture that mimicked the organ where growth occurred, nor did the vessel microarchitecture appear comparable to the primary tumor. Rather, metastatic lesions showed considerable variability, suggesting that each secondary tumor is a distinct disease entity from a microenvironmental perspective.

CONCLUSIONS

The data indicate that more phenotypic heterogeneity in the tumor microenvironment exists in models of metastatic disease than has been previously appreciated, and this heterogeneity may better reflect the metastatic cancer in patients typically enrolled in early-stage Phase I/II clinical trials. Similar to the suggestion of others in the past, the use of models of established metastasis preclinically should be required as part of the anticancer drug candidate development process, and this may be particularly important for targeted therapeutics and/or nanotherapeutics.

Non-Contact High-Frequency Ultrasound Microbeam Stimulation: A Novel Finding and Potential Causes of Cell Responses

Invasiveness research is an essential step in breast cancer metastasis. The application of high-frequency ultrasound microbeam stimulation (HFUMS) offers a manner of determining the invasion potential of human breast cancer cells by eliciting the elevation of transient cytoplasmic calcium ions (Ca²⁺). The fluorescent index (FI), which is a composite parameter reflecting calcium elevations elicited by HFUMS, was shown to be higher in invasive breast cancer cells (MDA-MB-231) compared to weakly invasive breast cancer cells (MCF-7) using the low-intensity 50-MHz HFUMS. This novel finding shows significant difference from the reported studies in which MCF-7 cells showed no response to HFUMS. In addition to the negligible response of normal human breast cells (MCF-10A), HFUMS shows the potential to be capable of differentiating the normal cells from the cancer cells. To understand the mechanism of HFUMS worked on mechanotransduction in cells, different channel blockers were used to investigate the roles of specific channels during HFUMS. It was found that GsMTx4 (30 μM), a selective blocker of mechanosensitive Piezo channels, reduces the FI values significantly in MDA-MB-231 cells, while SKF-96365 (40 μM), a general TRP channel blocker, cannot induce the significant inhibition of FI values. The results indicate that Piezo channels may play the main role in invasion and metastatic propagation of cells.

Heterogeneous distribution of trastuzumab in HER2-positive xenografts and metastases: role of the tumor microenvironment

Most HER2-positive metastatic breast cancer patients continue to relapse. Incomplete access to all target HER2-positive cells in metastases and tumor tissues is a potential mechanism of resistance to trastuzumab. The location of locally bound trastuzumab was evaluated in HER2-positive tissues in vivo and as in vivo xenografts or metastases models in mice. Microenvironmental elements of tumors were related to bound trastuzumab using immunohistochemical staining and include tight junctions, vasculature, vascular maturity, vessel patency, hypoxia and HER2 to look for correlations. Trastuzumab was evaluated alone and in combination with bevacizumab. Dynamic contrast-enhanced magnetic resonance imaging parameters of overall vascular function, perfusion and apparent permeability were compared with matched histological images of trastuzumab distribution and vascular patency. Trastuzumab distribution is highly heterogeneous in all models examined, including avascular micrometastases of the brain and lung. Trastuzumab distributes well through the extravascular compartment even in conditions of high HER2 expression and poor convective flow in vivo. Microregional patterns of trastuzumab distribution in vivo do not consistently correlate with vascular density, patency, function or maturity; areas of poor trastuzumab access are not necessarily those with poor vascular supply. The number of vessels with perivascular trastuzumab increases with time and higher doses and dramatically decreases when pre-treated with bevacizumab. Areas of HER2-positive tissue without bound trastuzumab persist in all conditions. These data directly demonstrate tissue- and vessel-level barriers to trastuzumab distribution in vivo that can effectively limit access of the drug to target cells in brain metastases and elsewhere.

Synergistic inhibitory effects of an engineered antibody-like molecule ATF-Fc and trastuzumab on tumor growth and invasion in a human breast cancer xenograft mouse model

The overexpression of the oncogene human epidermal growth factor receptor 2 (HER-2) has been associated with decreased disease-free survival and is a marker of poor prognosis of invasive breast cancer. Although the high efficacy of trastuzumab, a drug that targets the HER-2 oncogene, has been widely recognized, the efficiency of the treatment remains at ~30%. Therefore, novel effective treatments are required for patients with recurrent metastatic breast cancer. The present study aimed to investigate the effects of an engineered antibody-like molecule administered alone or in combination with trastuzumab on the tumor growth and metastasis of HER-2-positive breast cancer. Another aim was to investigate novel cancer therapies for HER-2-positive breast cancer. The engineered antibody-like molecule consists of the amino-terminal fragment (ATF) of human urokinase-type plasminogen (uPA) and is conjugated with the Fc fragment of human immunoglobulin G1 (ATF-Fc). The anti-cancer effect of ATF-Fc (alone and in combination with trastuzumab) on tumor cells and in a nude mouse tumor model was evaluated by detecting the expression of uPA, urokinase plasminogen activator receptor (uPAR) and HER-2. In vitro experiments demonstrated that specifically blocking the uPA-uPAR and HER-2 signaling pathways may effectively promote the apoptosis of breast cancer cells. Additionally, ATF-Fc-induced cell death in HER-2-positive breast cancer cells was observed in vivo. When ATF-Fc was administered in combination with trastuzumab, cell death was increased and breast cancer metastasis was reduced. The novel engineered antibody-like molecule ATF-Fc was able to inhibit HER-2-positive breast cancer cell growth and metastasis by interfering with uPA and its receptor (uPA-uPAR) system. Additionally, the antibody-like molecule exhibits a synergistic inhibitory effect when administered in combination with trastuzumab.

Cancer testis antigen Sperm Protein 17 as a new target for triple negative breast cancer immunotherapy

Breast carcinoma is a major health issue for millions of women. Current therapies have serious side effects, and are only partially effective in patients with metastatic tumors. Thus, the need for novel and less toxic therapies is urgent. Moreover, hormonal and antibody therapies effective in other subtypes are not effective in Triple Negative Breast Cancer (TNBC). Immunotherapeutic strategies directed against specific tumor-associated antigens (TAAs) and mediated by specific cytotoxic T lymphocytes (CTL) have been largely underexplored in this disease. Cancer-testis antigens (CTA) are a group of TAAs displaying the ideal characteristics of promising vaccine targets, i.e. strong immunogenicity and cancer specificity. The CTA, Sperm Protein 17 (SP17), has been found to be aberrantly expressed in different neoplasms, including ovarian and esophageal cancers, nervous system tumors and multiple myeloma, and has been suggested as a candidate target for immunotherapy.

Here, we evaluated SP17 expression levels in breast cancer cell lines, invasive ductal breast carcinoma, including patients with TNBC, and adjacent non-neoplastic breast tissue, and determined whether SP17 was capable of generating SP17-specific cytotoxic T lymphocytes in vitro.

We showed that SP17 is expressed in breast cancer cell lines and primary breast tumors and importantly in TNBC subtype, but not in adjacent non-tumoral breast tissue or unaffected tissues, except in male germinal cells. Furthermore, we detected specific anti-SP17 antibodies in patients’ sera and we generated SP17-specific, HLA class I-restricted, cytotoxic T lymphocytes capable of efficiently killing breast cancer cells.

Benefit of adjuvant chemotherapy with or without trastuzumab in pT1ab node-negative human epidermal growth factor receptor 2-positive breast carcinomas: results of a national multi-institutional study

PURPOSE

Benefit of adjuvant trastuzumab-based chemotherapy for node-positive and/or >1 cm human epidermal growth factor receptor 2-positive (HER2+) breast carcinomas has been clearly demonstrated in randomized clinical trials. Yet, evidence that adjuvant chemotherapy with or without trastuzumab is effective in pT1abN0 HER2+ tumors is still limited. The primary objective of this study was to investigate the impact of adjuvant chemotherapy ± trastuzumab on outcome in this subpopulation.

PATIENTS AND METHODS

A total of 356 cases of pT1abN0M0 HER2 + breast cancers were retrospectively identified from a large cohort of 22,334 patients, including 1248 HER2+ patients who underwent primary surgery at 17 French centers, between December 1994 and January 2014. The primary end point was disease-free survival (DFS). A multivariate Cox model was built, including adjuvant chemotherapy, tumor size, hormone receptor status, and Scarff Bloom Richardson (SBR) grade.

RESULTS

A total of 138 cases (39%) were treated with trastuzumab-based chemotherapy, 29 (8%) with chemotherapy alone, and 189 (53%) received neither trastuzumab nor chemotherapy. Adjuvant chemotherapy ± trastuzumab was associated with a significant DFS benefit (3-year 99 vs. 90%, and 5-year 96 vs. 84%, Hazard ratio, HR 0.26 [0.10-0.67]; p = 0.003, logrank test) which was maintained in multivariate analysis (HR 0.19 [0.07-0.52]; p = 0.001). Metastasis-free survival was also increased (HR 0.25 [0.07-0.86]; p = 0.018, logrank test) at 3-year (99 vs. 95%) and 5-year (98 vs. 89%) censoring. Exploratory subgroup analysis found DFS benefit to be significant in hormone receptor-negative, hormone receptor-positive, and pT1b tumors, but not in pT1a tumors.

CONCLUSIONS

Adjuvant chemotherapy ± trastuzumab is associated with a significantly reduced risk of recurrence in subcentimeter node-negative HER2+ breast cancers. Most of the benefit may be driven by pT1b tumors.

A phase-I study of lapatinib in combination with foretinib, a c-MET, AXL and vascular endothelial growth factor receptor inhibitor, in human epidermal growth factor receptor 2 (HER-2)-positive metastatic breast cancer

BACKGROUND

The mechanisms of resistance to anti-human epidermal growth factor receptor 2 (HER 2) therapies are unclear but may include the tyrosine-protein kinase Met (c-Met), vascular endothelial growth factor (VEGF) and AXL pathways. Foretinib is an inhibitor of c-Met, VEGF receptor 2 (VEGFR-2), platelet-derived growth factor receptor beta (PDGFRB), AXL, Fms-like tyrosine kinase 3 (FLT3), angiopoiten receptor (TIE-2), RET and RON kinases. This phase Ib study sought to establish the associated toxicities, pharmacokinetics (PK) and recommended phase II doses (RP2D) of foretinib and lapatinib in a cohort of HER-2-positive patients with metastatic breast cancer (MBC).

METHODS

Women with HER-2 positive MBC, Performance status (PS 0-2), and no limit on number of prior chemotherapies or lines of anti-HER-2 therapies were enrolled. A 3 + 3 dose escalation design was utilized. Four dose levels were intended with starting doses of foretinib 30 mg and lapatinib 750 mg orally once a day (OD) on a 4-weekly cycle. Assessment of c-MET status from the primary archival tissue was performed.

RESULTS

We enrolled 19 patients, all evaluable for toxicity assessment and for response evaluation. Median age was 60 years (34-86 years), 95% were PS 0-1, 53% were estrogen receptor-positive and 95% had at least one prior anti-HER-2-based regimen. The fourth dose level was reached (foretinib 45 mg/lapatinib 1250 mg) with dose-limiting toxicities of grade-3 diarrhea and fatigue. There was only one grade-4 non-hematological toxicity across all dose levels. There were no PK interactions between the agents. A median of two cycles was delivered across the dose levels (range 1-20) with associated progression-free survival of 3.2 months (95% CI 1.61-4.34 months). By immunohistochemical assessment with a specified cutoff, none of the 17 samples tested were classified as positive for c-Met.

CONCLUSIONS

The RP2D of the combined foretinib and lapatinib is 45 mg and 1000 mg PO OD, respectively. Limited activity was seen with this combination in a predominantly unselected cohort of HER-2-positive patients with MBC.

Locoregional Control According to Breast Cancer Subtype and Response to Neoadjuvant Chemotherapy in Breast Cancer Patients Undergoing Breast-conserving Therapy

BACKGROUND

Our group previously published data showing that patients could be stratified by constructed molecular subtype with respect to locoregional recurrence (LRR)-free survival after neoadjuvant chemotherapy and breast-conserving therapy (BCT). That study predated use of trastuzumab for human epidermal growth factor receptor 2 (HER2)-positive patients. The current study was undertaken to determine the impact of subtype and response to therapy in a contemporary cohort.

METHODS

Clinicopathologic data from 751 breast cancer patients who received neoadjuvant chemotherapy (with trastuzumab if HER2(+)) and BCT from 2005 to 2012 were identified. Hormone receptor (HR) and HER2 status were used to construct molecular subtypes: HR(+)/HER2(-) (n = 369), HR(+)/HER2(+) (n = 105), HR(-)/HER2(+) (n = 58), and HR(-)/HER2(-) (n = 219). Actuarial rates of LRR were determined by the Kaplan-Meier method and compared by the log-rank test. Multivariate analysis was performed to determine factors associated with LRR.

RESULTS

The pathologic complete response (pCR) rates by subtype were as follows: 16.5% (HR(+)/HER2(-)), 45.7% (HR(+)/HER2(+)), 72.4% (HR(-)/HER2(+)), and 42.0% (HR(-)/HER2(-)) (P < 0.001). Median follow-up was 4.6 years. The 5-year LRR-free survival rate for all patients was 95.4%. Five-year LRR-free survival rates by subtype were 97.2 % (HR(+)/HER2(-)), 96.1% (HR(+)/HER2(+)), 94.4% (HR(-)/HER2(+)), and 93.4% (HR(-)/HER2(-)) (P = 0.44). For patients with HR(-)/HER2(+) disease, the LRR-free survival rates were 97.4 and 86.7% for those who did and those who did not experience pCR, respectively. For patients with HR(-)/HER2(-) disease, the LRR-free survival rates were 98.6% (pCR) versus 89.9% (no pCR). On multivariate analysis, the HR(-)/HER2(-) subtype, clinical stage III disease, and failure to experience a pCR were associated with LRR.

CONCLUSIONS

Patients undergoing BCT after neoadjuvant chemotherapy have excellent rates of 5-year LRR-free survival that are affected by molecular subtype and by response to neoadjuvant chemotherapy.

Real-Life Use and Effectiveness of Adjuvant Trastuzumab in Early Breast Cancer Patients: A Study of the Southeast Netherlands Breast Cancer Consortium

BACKGROUND

The impact of drug prescriptions in real life as opposed to strict clinical trial prescription is only rarely assessed, although it is well recognized that incorrect use may harm patients and may have a significant impact on health care resources. We investigated the use and effectiveness of adjuvant trastuzumab in daily practice compared with the effectiveness in clinical trials.

METHODS

We included all patients with stage I-III invasive breast cancer, irrespective of human epidermal growth factor receptor 2 (HER2) status, diagnosed in five hospitals in the southeast of The Netherlands in 2005-2007. We aimed to assess the actual use of adjuvant trastuzumab in early HER2-positive breast and its efficacy in daily practice.

RESULTS

Of 2,684 patients included, 476 (17.7%) had a HER2-positive tumor. Of these, 251 (52.7%) patients had an indication for trastuzumab treatment of which 196 (78.1%) patients actually received it. Of the 225 patients without an indication, 34 (15.1%) received trastuzumab. Five-year disease-free survival was 80.7% for (n = 230) patients treated with versus 68.2% for (n = 246) patients not treated with trastuzumab (p = .0023), and 5-year overall survival rates were 90.7% and 77.4%, respectively (p = .0002). The hazard ratio for disease recurrence was 0.63 (95% confidence interval, 0.37-1.06) for trastuzumab when adjusting for potential confounders.

CONCLUSION

This study shows that in real life, patients treated with trastuzumab in early-stage HER2-positive breast cancer had a 5-year disease-free and overall survival comparable to prior randomized trials. For informative decision making, real-life data are of additional value, providing insight on outcome of patients considered ineligible for treatment.

Tumor location is a prognostic factor for survival of Chinese women with T1-2N0M0 breast cancer

OBJECTIVE

The purpose of this study was to investigate the effects of primary tumor location on the survival of Chinese women with T1-2N0M0 breast cancer.

METHODS

The clinical data of 1044 patients with stage T1-2N0M0 breast cancer who were treated from 1999 to 2007 were retrospectively analyzed. Patients were divided according to the primary tumor location: upper-outer quadrant (UOQ), upper-inner quadrant (UIQ), lower-outer quadrant (LOQ), lower-inner quadrant (LIQ), and nipple and central breast (central). The effect of primary tumor location on recurrence-free survival (RFS) and overall survival (OS) were determined.

RESULTS

The median age at diagnosis was 47 years. The tumor was located in the UOQ in 524 patients (50.2%), the LOQ in 124 (11.9%), the UIQ in 229 (21.9%), the LIQ in 59 (5.7%), and centrally in 108 patients (10.3%). The 5- and 10-year RFS and OS of the LIQ group were significantly poorer than that of patients in the other groups (RFS: 72.1% vs. 82.2-86.7%, P = 0.041; OS: 73.6% vs. 85.3-89.1%, P = 0.024). Multivariate Cox analysis showed that primary tumor location in the LIQ was an independent prognostic factor for RFS (hazard ratio [HR] = 2.977; 95% confidence interval [CI] 1.219-7.273; P = 0.017) and OS (HR = 2.949; 95% CI 1.207-7.208; P = 0.018).

CONCLUSION

Primary tumor location is an important prognostic factor for survival of Chinese women with T1-2N0M0 breast cancer.

Guideline concordant therapy prolongs survival in HER2-positive breast cancer patients: results from a large population-based cohort of a cancer registry

Even though randomized controlled clinical trials demonstrated improved survival by adjuvant trastuzumab treatment of HER2-positive breast cancer patients, data on its effect in clinical routine are scarce. This study evaluated the use and efficacy of trastuzumab in routine treatment of HER2-positive breast cancer patients. Data from the clinical cancer registry Regensburg (Germany) were analyzed. The present study investigated 6,991 female patients with primary invasive breast cancer. In premenopausal HER2-positive patients a considerable increase of trastuzumab therapy was observed from 58.1% in 2006 to 90.9% in 2011, whereas in postmenopausal patients trastuzumab was rather used on a constant rate of 49.1%. Best overall survival (OS) was found in HER2/steroid hormone receptor-positive patients receiving guideline concordant treatment with trastuzumab plus chemotherapy (CHT) plus antihormone therapy (AHT) with a 7-year OS rate of 96% compared to the non-trastuzumab group with a 7-year OS rate of 92%. In multivariable analysis, HER2-positive patients treated with CHT or AHT who did not get trastuzumab, had a worse 7-year OS (65%, P = 0.006 versus 79%, P = 0.017) than the control groups. This population-based study demonstrated that guideline concordant use of adjuvant trastuzumab improves OS for HER2-positive breast cancer patients treated in routine clinical care.

Investigating contactless high frequency ultrasound microbeam stimulation for determination of invasion potential of breast cancer cells

In this article, we investigate the application of contactless high frequency ultrasound microbeam stimulation (HFUMS) for determining the invasion potential of breast cancer cells. In breast cancer patients, the finding of tumor metastasis significantly worsens the clinical prognosis. Thus, early determination of the potential of a tumor for invasion and metastasis would significantly impact decisions about aggressiveness of cancer treatment. Recent work suggests that invasive breast cancer cells (MDA-MB-231), but not weakly invasive breast cancer cells (MCF-7, SKBR3, and BT-474), display a number of neuronal characteristics, including expression of voltage-gated sodium channels. Since sodium channels are often co-expressed with calcium channels, this prompted us to test whether single-cell stimulation by a highly focused ultrasound microbeam would trigger Ca(2+) elevation, especially in highly invasive breast cancer cells. To calibrate the diameter of the microbeam ultrasound produced by a 200-MHz single element LiNbO3 transducer, we focused the beam on a wire target and performed a pulse-echo test. The width of the beam was ∼17 µm, appropriate for single cell stimulation. Membrane-permeant fluorescent Ca(2+) indicators were utilized to monitor Ca(2+) changes in the cells due to HFUMS. The cell response index (CRI), which is a composite parameter reflecting both Ca(2+) elevation and the fraction of responding cells elicited by HFUMS, was much greater in highly invasive breast cancer cells than in the weakly invasive breast cancer cells. The CRI of MDA-MB-231 cells depended on peak-to-peak amplitude of the voltage driving the transducer. These results suggest that HFUMS may serve as a novel tool to determine the invasion potential of breast cancer cells, and with further refinement may offer a rapid test for invasiveness of tumor biopsies in situ.