Circulating HER2 Extracellular Domain Research Articles

Use of translational modeling and simulation for quantitative comparison of PF-06804103, a new generation HER2 ADC, with Trastuzumab-DM1

A modeling and simulation approach was used for quantitative comparison of a new generation HER2 antibody drug conjugate (ADC, PF-06804103) with trastuzumab-DM1 (T-DM1). To compare preclinical efficacy, the pharmacokinetic (PK)/pharmacodynamic (PD) relationship of PF-06804103 and T-DM1 was determined across a range of mouse tumor xenograft models, using a tumor growth inhibition model. The tumor static concentration was assigned as the minimal efficacious concentration. PF-06804103 was concluded to be more potent than T-DM1 across cell lines studied. TSCs ranged from 1.0 to 9.8 µg/mL (n = 7) for PF-06804103 and from 4.7 to 29 µg/mL (n = 5) for T-DM1. Two experimental models which were resistant to T-DM1, responded to PF-06804103 treatment. A mechanism-based target mediated drug disposition (TMDD) model was used to predict the human PK of PF-06804103. This model was constructed and validated based on T-DM1 which has non-linear PK at doses administered in the clinic, driven by binding to shed HER2. Non-linear PK is predicted for PF-06804103 in the clinic and is dependent upon circulating HER2 extracellular domain (ECD) concentrations. The models were translated to human and suggested greater efficacy for PF-06804103 compared to T-DM1. In conclusion, a fit-for-purpose translational PK/PD strategy for ADCs is presented and used to compare a new generation HER2 ADC with T-DM1.

ELISA assay employing epitope-specific monoclonal antibodies to quantify circulating HER2 with potential application in monitoring cancer\xa0patients undergoing therapy with trastuzumab

Circulating HER2 extracellular domain (HER2 ECD) levels were proposed as a surrogate for HER2 tissue expression to monitor breast cancer patients for early relapse or responses to standard or HER2-targeted therapies, such as the monoclonal antibody (mAb) trastuzumab. Currently, available commercial ELISA assays for HER2 ECD rely on antibodies recognizing undisclosed or unknown epitopes. In this work, two ELISA assays employing MGR2 and MGR3 epitope-specific mAbs for HER2 ECD were developed and validated, showing good assay precision and linearity of the dose-response signal within the dynamic range of 0.19–12.50 ng mL−1 and detection limits of 0.76 and 0.75 ng mL−1 for the MGR2 and MGR3 assays, respectively. The developed assay showed a good agreement with two widely used commercial kits for HER2 ECD quantification in serum samples from breast cancer patients. A complete characterization of mAb-HER2 ECD interaction was performed by means of surface plasmon resonance using trastuzumab as control for both epitope mapping and kinetics analysis. The epitopes recognized by the two mAbs showed no overlap with trastuzumab, which was confirmed by trastuzumab interference analysis in serum samples. The method showed to be a practical approach to determine HER2 ECD with a high degree of sensitivity, reliability and recovery in samples containing mAbs-based therapies.

Prognostic impact of circulating HER2 extracellular domain (ECD) in women with metastatic breast cancer.

e22038 Background: Overexpression of HER2, usually as a result of HER2 gene amplification, occurs in approximately 25% of breast cancers and is significantly associated with aggressive disease and ...

Circulating HER2 Extracellular Domain: A Specific and Quantitative Biomarker of Prognostic Value in all Breast Cancer Patients?

The HER2 oncoprotein has emerged as an essential biomarker in the treatment of breast cancer patients. Once the primary breast cancer is removed, there is an increasing need to detect breast cancer recurrence as early as possible with the hope that earlier intervention with new anti-HER2 therapies will improve quality of life and increase overall survival. Numerous publications have shown that increasing blood levels of circulating HER2 is an early indicator of progression, particularly in HER2-positive patients and that the rise and fall parallels the clinical course of disease and independent of therapy. Many studies show that the HER2 status of the primary tumor may not fully and accurately reflect the HER2 status of recurrent cancer. Thus, elevated serum HER2 levels may be an early signal of the emergence of a HER2-positive metastatic tumor and therefore alert the physician to re-assess HER2 status using a tissue test.

Abstract P4-09-09: Circulating HER2 extracellular domain (ECD) levels are associated with progression-free survival in metastatic breast cancer patients

Abstract Background: The human epidermal growth factor (HER2/neu) oncoprotein is composed of an intracellular tyrosine kinase portion, a short transmembrane section, and an extracellular ligand-binding domain (ECD). The latter is frequently cleaved from the surface of breast cancer cells and the serum HER2 ECD levels can be detected by enzyme-linked immunosorbent assay (ELISA). Consistent with majority of reports, our prior study showed that high circulating levels of the HER2 ECD indicates poor prognosis in 207 patients with metastatic breast cancer. In the present study, we aimed to elucidate whether serum HER2 ECD levels would predict the clinical outcome of metastatic breast cancer patients. Methods: Till May 19, 2012, one hundred ninty metastatic breast cancer patients were followed up. Serum was available from 190 patients at baseline, 46 patients in the assessment of time. Serum HER2 ECD levels were measured by ELISA. Disease state was assessed using Response Evaluation Criteria in Solid Tumors (RECIST). Progression-free survival (PFS) was defined as the interval from the time of randomization until the first documentation of disease progression or death due to any cause. PFS and median PFS were generated by Kaplan-Meier spots. Results: Elevated baseline HER2 ECD levels (bECD) (≥15 ng/ml) were observed in 40% (40/100) of patients with HER2-amplified tumors and 21.8% (19/87) of patients with HER2-negative tumors. Patients with bECD-elevated disease had a median PFS of 356 days compared with 229 days for patients with bECD-low disease(P = 0.001). In HER2-amplified cohort, median PFS for patients with low bECD levels was longer than those with bECD-elevated disease (391 days v 226 days, P = 0.005). And patients with low bECD levels treated with Herceptin-based regimen (n = 36) had a trend of longer PFS than patients(n = 24) treated with non-Herceptin regimen(447 days v 298 days, P = 0.227). Moreover, bECD-low patients (n = 36) showed a significantly longer median PFS than bECD-elevated patients(n = 22) when treated with Herceptin-based scheme (447 days v 229 days, P = 0.004). While, in patients with increased bECD levels, there was no statistical difference between Herceptin-treated groups (n = 22) and non-Herceptin-treated groups (n = 14) (229 days v 173 days, P = 0.761). In the HER2-negative group, patients with bECD-low disease had a median PFS of 313 days compared with 206 days for patients with bECD-elevated disease (P = 0.02). In a cohort of 46 patients whose HER2 ECD levels were monitored during treatment, 29 patients remains low ECD levels, 12 patients convert from elevated to low, 2 patients convert from low to high, and 3 patients remains elevated HER2 ECD levels. The patients who remained low ECD levels or achieved low ECD leves have significantly longer PFS than those whose levels remained above 15ng/mL or converted from low to high regardless of treatment given (440 days v 192days, P = 0.019). Conclusion: Elevated HER2 bECD predicts poor median PFS irrespective of HER2 status. HER2-amplified patients with low-HER2 ECD levels may get more benefit from Herceptin-based scheme. Remained low-HER2 ECD levels or decreases in serum HER2 ECD levels during treatment were associated with longer median PFS in metastatic breast cancer. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-09-09.

Abstract P2-05-05: Circulating HER2 extracellular domain (ECD) predicts a poor prognosis for metastatic breast cancer patients

Abstract Background: Amplification or overexpression of HER2 has been shown to play an important role in approximately 30% of breast cancers and is strongly associated with increased recurrence and a worse prognosis. The HER2 extracellular domain (ECD) may be cleaved and shed from the surface of breast cancer cells and serum HER2 ECD levels can be detected by enzyme-linked immunosorbent assay (ELISA). In this study, we explored the relationship between circulating HER2 ECD and tissue HER2 status, then we also examined its predictive value in a cohort of metastatic breast cancer patients. Methods: Two hundred and seven metastatic breast cancer patients from March 2009 to July 2011 were involved in this prospective study at Zhejiang Cancer Hospital. The patients were identified histopathologically as having breast cancer by pathologists and staged mainly based on the pathology, the clinical manifestation, and the imaging findings of CT and MRI according to the classification system of the International Union Against Cancer. Serum HER2 ECD levels were measured by ELISA. Tissue HER2 was determined by IHC and FISH in tumor samples, respectively. Results: The level of serum HER2 ECD was at least more than 15 ng/ml in 31.4% (65/207) metastatic breast cancer patients, 39.1%(43/110) in HER2-positive patients and 23.4%(22/94) in HER2-negative cases, respectively, P = 0.017. We also found that high serum HER2 ECD levels (≥15 ng/ml) were significantly associated with elevated serum CEA (52.1% v 21.5%, OR 3.978, 95%CI 2.138–7.401, P = 0.000), CA125 (48.5% v 23.5%, OR 3.064, 95%CI 1.650–5.691, P = 0.000), CA153 (53.2% v 17.1%, OR 5.48, 95%CI 2.897–10.366, P = 0.000), LDH (53.3% v 23.1%, OR 3.798, 95%CI 2.011–7.173, P = 0.000) and AKP (51.2% v 26.5%, OR 2.911, 95%CI 1.442–5.879, P = 0.002), respectively. For the effect of HER2 ECD on the site of relapse, still there were statistically significant correlation between increased serum HER2 ECD levels and liver involvement (42.7% v 24.0%, OR 2.358, 95%CI 1.294–4.297, P = 0.005), brain metastasis (50.0% v 26.7%, OR 2.744, 95%CI 1.397–5.391, P = 0.003) and visceral involved (37.9% v 14.8%, OR 3.511, 95%CI 1.548–7.961, P = 0.002), respectively. While serum HER2 ECD levels were not related to age, BMI, tumor size, lymph node involvement and hormone receptors status, respectively (P>0.05). Conclusions: Monitoring the circulating levels of the HER2 ECD in patients with metastatic breast cancer provides a real-time assessment of tumor burden and indicates poor prognosis, and may provide important information for reassessment of HER2 in HER2-negative metastatic breast cancer. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-05-05.

Resistance to HER2-targeted therapy: mechanisms of trastuzumab resistance and possible strategies to overcome unresponsiveness to treatment

Trastuzumab has shown significant efficacy in HER2-overexpressing breast cancers and is approved for patients whose tumors carry this abnormality, both in the metastatic and in the adjuvant settings. However, several issues about its optimal use remain unresolved. Many breast cancer patients with HER2 overexpression do not respond to initial therapy with trastuzumab (Herceptin(®)), and a vast majority of these develop resistance to this monoclonal antibody within one year. This review discusses the molecular mechanisms leading to the development of trastuzumab resistance, including circulating HER2 extracellular domain, loss of PTEN, activation of alternative pathways (e.g. IGFR), and receptor-antibody interaction block. Additionally, the possibility of exploring these aberrations as therapeutic targets that potentially overcome resistance to trastuzumab is highlighted.

Clinical Benefit of INCB7839, a Potent and Selective Inhibitor of ADAM10 and ADAM17, in Combination with Trastuzumab in Metastatic HER2 Positive Breast Cancer Patients.

Abstract Background: In HER2 over-expressing breast cancer cells, the HER2 protein can be cleaved by a metalloproteinase, ADAM10. While the extracellular domain (ECD) of HER2 is released into the serum, the truncated HER2 receptor fragment, termed p95, remains in the tumor cell membrane as a constitutively active receptor tyrosine kinase. Previous studies have shown that the presence of p95 in tumor cells is associated with poor clinical outcomes in patients with metastatic HER2 positive breast cancer and it was recently shown that patients with p95+ HER2 positive breast cancer are resistant to trastuzumab-based therapy. Therefore, inhibition of HER2 cleavage by the ADAM10/ADAM17 inhibitor, INCB7839, which reduces the formation of soluble HER2 ECD as well as p95 levels in the tumor, may enhance the clinical efficacy of trastuzumab in HER2+ breast cancer patients. Materials and Methods: This study is a single arm modified dose escalation open label trial of INCB7839 + trastuzumab in women with HER2+ metastatic breast cancer, naïve to chemotherapy. Three doses of INCB7839 were studied (100 mg, 200 mg, 300 mg BID) with 6 patients/cohort and an expansion arm at the 300mg BID dose. Herceptin was administered on a Q3 week schedule. Pharmacokinetics, plasma HER2 ECD levels and p95 expression in tumor tissue were assessed in addition to clinical response and safety. Results: 39 patients have been enrolled in the study and assessment of HER2 ECD levels, p95 status and best clinical response completed on 30 patients. INCB7839 administration results in a dose-dependent reduction in the elevated levels of circulating HER2 ECD with a mean of ∼80% inhibition achieved at the highest dose tested (300 mg BID). At the 300mg BID dose, the current overall response rate is 40% (6/15 evaluable patients) with a higher response rate (6/11 or 55%) observed in patients with average plasma concentrations of INCB7839 above the IC50 for reduction of ECD levels, 320nM. Importantly, INCB7839 increases the clinical response rate in p95+ patients, with equivalent responses observed in the p95+ and p95- patients treated with INCB7839 + trastuzumab. The combination has been generally safe and well tolerated. Discussion: Proteolytic cleavage of the HER2 receptor by ADAM proteases results in the formation of a cytoplasmic fragment (p95) that possesses constitutive kinase activity with the release of ECD. Importantly, elevated levels of ECD and/or p95 have been associated with poor prognosis and clinical data suggest that p95 affords resistance to trastuzumab. Biomarker and clinical data from this trial demonstrate that INCB7839 can markedly reduce HER2 cleavage in patients with HER2+ breast cancer, and suggests that INCB7839, by inhibiting the HER2 shedding process, can render a subpopulation of HER2+ patients (as defined by the presence of p95) that would be predicted to be trastuzumab resistant clinically responsive to trastuzumab therapy. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5056.

Fatty acid synthase activity regulates HER2 extracellular domain shedding into the circulation of HER2-positive metastatic breast cancer patients

Clinicopathological assessment of the functional relationship between the HER2 oncogene and tumor-associated fatty acid synthase (FASN) is largely precluded because immunohistochemical and/or mRNA studies should be performed in biopsies from breast cancer patients. We here sought to determine whether serum FASN (sFASN) could associate with circulating HER2 extracellular domain (HER2 ECD) in the blood of metastatic breast cancer (MBC) patients. Concentrations of serum FASN and HER2 ECD were measured with ELISA in sera retrospectively obtained from 201 patients with metastatic breast cancer (MBC) and 31 healthy subjects. Mechanistical in vitro studies were performed using pharmacological inhibitors of HER2 and FASN as well as cultured cancer cells engineered to overexpress HER2 and FASN human genes. When the upper limit of normal sFASN was defined as the mean + 2SD of the control group, sFASN was elevated above this cut-off (12 ng/ml) in 70 MBC patients (35%). Eighty-nine MBC patients (44%) had elevated levels of HER2 ECD (HER2 ECD cut-off = 15 ng/ml). HER2 ECD-positive MBC patients slightly increased their sFASN levels compared with HER2 ECD-negative MBC patients. sFASN-positive MBC patients had significantly increased levels of HER2 ECD when compared with sFASN-negative MBC patients (mean HER2 ECD=34 ng/ml, 95% CI 26-41 ng/ml and 18 ng/ml -95% CI 15-21 ng/ml, respectively; p=0.002). Sixty percent of sFASN-positive patients concurrently exhibited high levels of HER2 ECD whereas 64% of sFASN-negative patients were negative for circulating HER2 ECD. In vitro studies revealed that BC cells bearing HER2 gene-amplification released higher levels of extracellular FASN than HER2-negative BC cells. Trastuzumab-induced blockade of HER2 ECD shedding failed to prevent FASN release and retrovirally-induced HER2 overexpression in MCF-7 cells did not increase extracellular FASN. Of note, pharmacological inhibition of FASN activity significantly decreased HER2 ECD levels in the supernatant of HER2-overexpressing BC cells while transient overexpression of FASN gene in HBL100 cells promoted FASN protein release and concomitantly increased HER2 ECD shedding into the extracellular milieu. Subsequent studies should explore if quantitative determination of FASN molecules in blood could become a rapid and accurate non-invasive test to monitor disease progression and survival in HER2-overexpressing MBC undergoing HER2-targeted therapies.

Commentary: Can Circulating HER-2 Extracellular Domain Predict Response to Trastuzumab in HER-2–Negative Breast Cancer?

Abstract This commentary evaluates the study of Ardavanis et al. in this issue and makes recommendations for further studies of HER-2 extracellular domain circulating levels as a prognostic indicator in metastatic breast cancer.

High circulating HER2 extracellular domain levels correlate with reduced efficacy of an aromatase inhibitor in hormone receptor‐positive metastatic breast cancer: A confirmatory prospective study

In this specifically designed, prospective study, the authors addressed the predictive value of circulating levels of the extracellular domain (ECD) of HER2 in patients with metastatic breast cancer who were treated with letrozole. Two hundred twenty-six patients with hormone receptor-positive, metastatic breast cancer received letrozole (2.5 mg daily) until they developed either disease progression or unacceptable toxicity. Efficacy was measured primarily as the time to progression (TTP) and, secondarily, as the objective response rate (ORR) and overall survival. HER2 ECD levels were determined by using a sandwich enzyme HER2/neu immunoassay before letrozole treatment was initiated. Positive HER2 ECD status was correlated with treatment efficacy. Forty-two patients (19%) had elevated HER2 ECD levels, which were associated with primary tumor HER2 expression (P < .001) but not with age, performance status, location, or number of metastatic sites. The median TTP was significantly shorter among patients who had elevated HER2 ECD compared with the median TTP among patients who had normal levels (4 months vs 14 months; P = .0004), and the ORR was lower in the group with elevated HER2 ECD levels (14% vs 30%; P < .036). Overall survival was significantly shorter among patients with elevated serum HER-2 ECD (P < .0005). Elevated HER2 ECD concentrations predicted poorer outcomes in postmenopausal women with metastatic hormone receptor-positive breast cancer who were treated with aromatase inhibitors like letrozole.

From the trastuzumab era to new target therapies: beyond revolution

In October 2005 edition of The New England Journal of Medicine, Gabriel Hortobagy claimed that the results of trastuzumab adjuvant trials are not evolutionary but revolutionary [1]. In effect, from early results of first target therapy, tamoxifene, this is first time that such enthusiastic and dramatic results, in terms of outcome of an adjuvant therapy, have been realized. Interim analysis of four randomized phase III trials, in patients with HER2-positive early-stage breast cancer, indicated significant improvement in disease-free survival (DFS) compared with chemotherapy alone [hazard ratio (HR) 0.48-0.64] and an overall survival (OS) benefit in three of four trials (NCCTG N9831/NSABP B-31: HR 0.67, P = 0.015; HERA: HR 0.66; P = 0.0115) when trastuzumab was added to standard therapy. It is obvious that there are certain limitations in use of this extraordinary drug. The first is that trastuzumab can only be used in a small number of patients; majority (HER-2 negative) cannot benefit from its use. The second problem is potential cardiotoxicity of this treatment. In clinical practice, treatment with trastuzumab can be resumed when patients are no longer symptomatic and cardiac function is normalized. The third dilemma is whether duration of therapy should be short or prolonged. The fourth problem concerns high cost of trastuzumab treatment to National Health Service, which is not to be disregarded. Finally, fifth dilemma is to decide which patients should be treated with trastuzumab. It is obvious that all node-positive patients should receive treatment, but probably not all node-negative patients. Other potential strategies for evaluating response to trastuzumab therapy might include assessment of surrogate markers of critical HER2-mediated signaling pathways, including PI3K/Akt pathway, and circulating HER2 extracellular domain levels. In addition, NSABP B-31 trial identified c-Myc amplification as a predictive factor for responsiveness to trastuzumab. Acquired and de novo resistance to trastuzumab is a significant clinical challenge.

Selective inhibition of ADAM metalloproteases blocks HER-2 extracellular domain (ECD) cleavage and potentiates the anti-tumor effects of trastuzumab

13021 Background: HER-2, a member of ErbB family of receptor tyrosine kinases, is an important regulator of cell proliferation and survival, and is a clinically validated target of therapeutic intervention in HER-2 positive metastatic breast cancer patients. In HER-2 overexpressing cells, the extracellular domain (ECD) is frequently cleaved, rendering the remaining transmembrane portion of HER-2 (p95) constitutively active. The presence of both serum ECD and cellular p95 protein have been linked to poor clinical outcome as well as reduced effectiveness of some therapeutic treatments, suggesting that signaling via p95 is clinically relevant and may represent an attractive target for therapeutic intervention. Methods: Through medicinal chemistry efforts, we have identified a series of potent, selective small molecule inhibitors of ADAM metalloproteases, exemplified here by INCB7839. These compounds were tested both in vitro and in vivo for inhibition of HER-2 ECD cleavage and anti-tumor activity in the HER-2 overexpressing BT-474 cell line. Inhibition of circulating HER-2 ECD levels was monitored in a phase I multiple dose escalation study in healthy volunteers. Results: We demonstrate that these inhibitors effectively blocked HER-2 cleavage in HER-2 overexpressing human breast cancer cell lines. When used in combination, INCB7839 dramatically enhanced the antiproliferative activity of suboptimal doses of the anti-HER-2 antibody, trastuzumab, in HER-2 overexpressing/shedding breast cancer cell lines, accompanied by reduced ERK and AKT phosphorylation. Consistent with these in vitro data, INCB7839 reduced serum ECD levels in tumor-bearing mice and enhanced the antitumor effect of trastuzumab in a xenograft tumor model derived from the HER-2 overexpressing BT-474 breast cancer cell line. In a phase I clinical trial, INCB7839 demonstrated a dose-dependent decrease in the circulating levels of HER-2 ECD present in healthy volunteers. Conclusions: Collectively, these findings suggest that blocking HER-2 cleavage with selective ADAM inhibitors, especially in combination with anti-HER-2 antibody therapy, may represent a novel approach for treating HER-2 overexpressing breast cancer patients. [Table: see text]

SERUM LEVELS OF SHED HER2/NEU PROTEIN IN MEN WITH PROSTATE CANCER CORRELATE WITH DISEASE PROGRESSION

We determined the association between serum levels of shed Her-2/neu protein and disease progression in men with prostate cancer. Serum from 279 patients enrolled in a prospective serum bank and database at New York University Medical Center was analyzed using the Food and Drug Administration approved Immuno-1 Her-2/neu assay. Patients were classified by the Prostate-Specific Antigen Working Group model into 5 groups, namely group 1-no evidence of cancer in 60, group 2-clinically localized disease in 67, group 3-prostate specific antigen increasing after therapy and no clinical metastases in 77, group 4-clinical metastases and castration sensitivity in 42, and group 5-clinical metastases and castration resistance in 33. A cutoff of 14 ng/ml for normal serum Her-2/neu was established based on the 95th order statistic in group 1. Of 279 patients 37 (13.3%) had increased serum Her-2/neu, that is 5%, 11.9%, 10.4%, 16.7% and 33.3% in groups 1 to 5, respectively. There was a significant difference between patients with (groups 4 and 5) and without (groups 2 and 3) clinical metastases (p = 0.006). In group 5 patients serum Her-2/neu was significantly higher than in group 2 patients (p <0.02). The risk of cause specific death increased significantly with each unit increase in serum Her-2/neu (p <0.001). Increased serum Her-2/neu correlates with the presence of metastatic disease and it may indicate an increased risk of death in patients with castrate, metastatic prostate cancer. The detection of serum Her-2/neu is a minimally invasive alternative to tumor sampling for identifying potential candidates for anti-Her-2/neu treatment strategies. Further studies are needed to optimize this assay for application in the clinical setting.

Docetaxel plus epirubicin as first-line chemotherapy in MBC (KCSG 01-10-05): Phase II trial and the predictive values of circulating HER2 extracellular domain and vascular endothelial growth factor

The anthracyclines and taxanes are considered to be the most active drugs in metastatic breast cancer (MBC). We conducted a multicenter phase II study to evaluate the efficacy and tolerability of the docetaxel plus epirubicin combination chemotherapy as first-line treatment in MBC and performed a prospective assessment of the predictive values of circulating HER2 extracellular domain (ECD) and vascular endothelial growth factor (VEGF). Docetaxel 75 mg/m(2) and epirubicin 75 mg/m(2) were given intravenously every 3 weeks. Prophylactic G-CSF was not used. Pretreatment serum HER2 ECD and VEGF levels were measured by enzyme immunoassay. Forty MBC patients were enrolled, and 39 patients were evaluable for toxicities and 38 for response. Complete response was observed in 3 (7.9%) patients, partial response in 20 (52.6%) (overall response rate 60.5%), stable disease in 11 (28.9%) and disease progression in 4 (10.5%). After a median follow-up of 22.5 months, the median duration of response was 28 weeks, median time to disease progression was 32 weeks, and median survival was 15.8 months. Two-hundred and fifteen cycles of treatment were administered (median, 6 cycles per patient). Grade 3 and 4 neutropenia were observed during 24 (11.2%) and 74 (35%) cycles respectively, and grade 3 or 4 febrile neutropenia in 24 (11.2%) cycles. Elevated circulating HER2 ECD levels were found to be associated with a shorter response duration (p<0.005) and shorter time to progression (p<0.005). However, elevated VEGF levels were not found to be correlated with response rate or survival. We concluded that the docetaxel and epirubicin combination is an effective first-line treatment in MBC patients and that elevated serum HER2 ECD levels, but not circulating VEGF levels, predict a poor outcome.

Serum HER2 extracellular domain in metastatic breast cancer patients treated with weekly trastuzumab and paclitaxel: association with HER2 status by immunohistochemistry and fluorescence in situ hybridization and with response rate

PurposeWe explored the relationship between circulating HER2 extracellular domain (ECD) and tissue HER2 status as determined by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). We also examined its predictive value in a cohort of metastatic breast cancer patients treated with weekly trastuzumab and paclitaxel. MethodsEligible patients had pre- and post-treatment stored serum specimens and were treated on a previously reported phase II trial. Retrospective analysis evaluated: the association between pretreatment serum HER2 ECD and tissue HER2 status by IHC and FISH; and the association between change in serum HER2 ECD after 12 weeks of therapy and response proportion. ResultsStored serum samples were available for 55/95 (58%) patients. Statistically significant associations were found between HER2 status as assessed by IHC and FISH, and baseline serum HER2 ECD level. Patients whose ECD normalized after 12 weeks of therapy had a higher response proportion compared with patients with persistently high ECD levels (68% versus 15%, P=0.005). A relative decline of over 55% from baseline HER2 ECD predicted response to therapy. ConclusionA statistically significant association was observed between pretreatment serum HER2 ECD and tissue HER2 status as assessed by IHC and FISH. A decrease in serum HER2 ECD level was a significant predictor of response to trastuzumab-based therapy.

Comparison of Pre- and Postsurgical Concentrations of Blood HER-2 mRNA and HER-2 Extracellular Domain Reflects HER-2 Status in Early Breast Cancer

The HER-2 gene (HER-2/neu or c-erbB-2) encodes an 185-kDa transmembrane glycoprotein that is a member of the type I family of growth factor receptors. HER-2 is constitutively activated by overexpression and contributes to cell growth, angiogenesis, survival, and metastasis (1). The assessment of HER-2 status in breast carcinomas provides valuable prognostic and predictive information. Immunohistochemistry, fluorescence in situ hybridization, chromosomal in situ hybridization, and quantitative reverse transcription-PCR (RT-PCR) may be used for this purpose. Other approaches have been proposed for the assessment of HER-2 status in peripheral blood, including evaluating either circulating HER-2 extracellular domain (ECD) or nucleated cell-associated HER-2 mRNA. Some studies have indicated that circulating ECD/HER-2 is frequently increased in metastatic disease (2)(3)(4). In addition, high concentrations of ECD/HER-2 are associated with cancer aggressiveness (5) and predict response to trastuzumab (6)(7)(8) and antiestrogen (4) therapies in advanced breast cancer. Recently, Martin et al. (9), using an array to assess circulating mRNA, pointed out that HER-2 mRNA was generally low in the blood of healthy individuals but was increased in 31% of patients with untreated invasive breast cancer. Almost all of these studies evaluated blood markers in patients with advanced or metastatic breast cancer using a single presurgical sample. Our study included 40 consecutive patients (median age, 58 years; range, 29–80 years) undergoing surgery for early breast cancer. Patients did not receive any systemic therapy before surgery and provided informed consent for the study. According to tumor size, 28 patients were classified as T1, whereas the remaining 12 were T2 or T3. Twenty-two were node negative, and 35 were positive for estrogen receptors. From each patient, we collected 12 mL of venous blood in EDTA tubes and divided the blood into two 5-mL aliquots. The first was centrifuged, and the plasma …

Effects of trastuzumab (H) and chemotherapy on circulating HER2 extracellular domain (ECD) in patients with metastatic breast cancer (MBC) and non-small cell lung cancer (NSCLC)

570 Background: H is a humanised monoclonal antibody directed at HER2. The extracellular domain (ECD) of the HER2 protein may be shed into the serum and is detectable using ELISA. A correlation has previously been suggested between baseline shed ECD and response. This relationship as well as the effect of trastuzumab [Herceptin (H)] and chemotherapy on ECD levels are investigated. Methods: Data are presented from 4 phase II/III clinical trials: Study BO15935: q3w H + paclitaxel (P) in MBC (N=30 patients analysed for ECD) Study M77001: q3w docetaxel (D) +/- qw H in MBC (N=135) Study WO16229: q3w H alone in MBC (N=98) Study BO15899: qw Gemcitabine/Cisplatin (GC) +/- H in NSCLC (N=103) ECD sampling frequency varied between studies from every cycle to every third cycle. Results: No clear relationship was found between baseline ECD levels and best clinical response. After the start of therapy, ECD levels fell irrespective of the agent(s) received. Cytotoxics +/- H resulted in rapid large reductions in ECD followed by a relative plateau (eg study M77001: median ECD declined from baseline of 30.2 ng/ml (n=136) to 9.8ng/ml (n=97) at cycle 6 (week 16)). However, H monotherapy led to a slower, more steady reduction over the duration of treatment (eg study WO16229: declined from baseline of 31.4 ng/ml (n=98) to 8.7 ng/ml (n=2) at cycle 24 (week 70)). There was no obvious difference in the course or the extent of decline when analysed by best response. Additional longitudinal analyses will be presented. Conclusions: In these studies including a total of 366 patients, there was no obvious relationship between baseline ECD levels and response. In all cases ECD levels dropped with antiproliferative therapy. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Roche Genentech; Lilly; Roche Roche AstraZeneca Hoffmann-LaRoche

Effects of trastuzumab (H) and chemotherapy on circulating HER2 extracellular domain (ECD) in patients with metastatic breast cancer (MBC) and non-small cell lung cancer (NSCLC)

Effects of trastuzumab (H) and chemotherapy on circulating HER2 extracellular domain (ECD) in patients with metastatic breast cancer (MBC) and non-small cell lung cancer (NSCLC)

HER-2/neu evaluation in breast cancer are we there yet?

The HER-2/neu oncogene is located on chromosome 17q and encodes a transmembrane glycoprotein with intracellular tyrosine kinase activity. Several studies have shown an association of HER-2 gene amplification or protein overexpression with prognosis and predictor of therapeutic response. Most important, the presence of amplification or overexpression is the basis of eligibility for trastuzumab therapy. However, there are several methods of determining HER-2 status, each measuring a different aspect such as DNA content, gene copy number, protein expression, expression of RNA, and circulating HER-2 extracellular domain protein. There is no consensus with regard to the optimal test for HER-2 assessment. This review examines the various methods used in an attempt to define the most accurate and reliable test. The most widely used assays are immunohistochemical analysis and fluorescence in situ hybridization (FISH), which measure protein expression and gene amplification, respectively. Based on current data, FISH is the most accurate and reproducible test with a better correlation with prognosis and response to therapy.