Clinical Activity of Trastuzumab and Vinorelbine in Women With HER2-Overexpressing Metastatic Breast Cancer

Unlocking the potential of oncology biomarkers: advancements in clinical theranostics

INTRODUCTION

Cancer biomarkers have revolutionized the field of oncology by providing valuable insights into tumor changes and aiding in screening, diagnosis, prognosis, treatment prediction, and risk assessment. The emergence of "omic" technologies has enabled biomarkers to become reliable and accurate predictors of outcomes during cancer treatment.

CONTENT

In this review, we highlight the clinical utility of biomarkers in cancer identification and motivate researchers to establish a personalized/precision approach in oncology. By extending a multidisciplinary technology-based approach, biomarkers offer an alternative to traditional techniques, fulfilling the goal of cancer therapeutics to find a needle in a haystack.

SUMMARY AND OUTLOOK

We target different forms of cancer to establish a dynamic role of biomarkers in understanding the spectrum of malignancies and their biochemical and molecular characterization, emphasizing their prospective contribution to cancer screening. Biomarkers offer a promising avenue for the early detection of human cancers and the exploration of novel technologies to predict disease severity, facilitating maximum survival and minimum mortality rates. This review provides a comprehensive overview of the potential of biomarkers in oncology and highlights their prospects in advancing cancer diagnosis and treatment.

Adjuvant trastuzumab and vinorelbine for early-stage HER2+ breast cancer

Background

The single-arm phase II APT trial established trastuzumab and paclitaxel (TH) as the standard adjuvant regimen for small human epidermal growth factor receptor 2 (HER2+) tumors. However, paclitaxel causes alopecia and has high rates of neuropathy and hypersensitivity reactions. In patients with metastatic HER2+ breast cancer (BC), the combination of trastuzumab and vinorelbine (TV) is effective and well tolerated. There is a need for alternative non-anthracycline/taxane-based regimens for patients with HER2+ early-stage BC, especially for those with contraindications or who wish to avoid side effects of taxane-based regimens. Here we describe our institutional experience with adjuvant TV for patients with early-stage HER2+ BC.

Methods

Clinicopathological characteristics, treatment details, and outcomes of patients with localized HER2+ BC treated with adjuvant TV from 2007 to 2021 at a large academic medical institution were collected. Study endpoints included invasive disease-free survival (IDFS), overall survival (OS), and safety/tolerability. IDFS and OS were measured from start date of TV treatment to date of event/last follow-up and date of death/last follow-up, respectively.

Results

A total of 30 patients were treated with TV. All patients received trastuzumab at standard dosing and vinorelbine at a starting dose of 25 mg/m² either on days 1/8 or on days 1/8/21 (weekly) of a 21-day cycle with four planned cycles. Median age at diagnosis was 59 years (range: 36-81). 90.3% of patients had anatomic pathologic stage IA BC and 9.7% stage IIA BC. Of the 30 patients, 24 of them opted to pursue TV due to concerns related to alopecia, neuropathy, and other toxicities, and 6 switched from treatment with TH to TV due to toxicities. Eight patients experienced neutropenia with no cases of febrile neutropenia. No patients experienced alopecia or long-term neuropathy. With a median follow-up of 68 months (5.7 years), the 5-year IDFS rate was 90.9%, with one local and one distant recurrence. The 5-year OS was 100%.

Conclusions

Trastuzumab in combination with vinorelbine in the adjuvant, early-stage setting for low-risk HER2+ BC demonstrated clinical efficacy and appeared to be well tolerated. TV warrants further evaluation as an alternative regimen to TH for patients with early-stage HER2+ BC.

Trastuzumab and paclitaxel in patients with EGFR mutated NSCLC that express HER2 after progression on EGFR TKI treatment

BACKGROUND

HER2 expression and amplification are observed in ~15% of tumour biopsies from patients with a sensitising EGFR mutation who develop EGFR TKI resistance. It is unknown whether HER2 targeting in this setting can result in tumour responses.

METHODS

A single arm phase II study was performed to study the safety and efficacy of trastuzumab and paclitaxel treatment in patients with a sensitising EGFR mutation who show HER2 expression in a tumour biopsy (IHC ≥ 1) after progression on EGFR TKI treatment. Trastuzumab (first dose 4 mg/kg, thereafter 2 mg/kg) and paclitaxel (60 mg/m²) were dosed weekly until disease progression or unacceptable toxicity. The primary end-point was tumour response rate according to RECIST v1.1.

RESULTS

Twenty-four patients were enrolled. Nine patients were exon 21 L858R positive and fifteen exon 19 del positive. Median HER2 IHC was 2+ (range 1-3). For 21 patients, gene copy number by in situ hybridisation could be calculated: 5 copies/nucleus (n = 9), 5-10 copies (n = 8), and >10 copies (n = 4). An objective response was observed in 11/24 (46%) patients. Highest response rates were seen for patients with 3+ HER2 IHC (12 patients, ORR 67%) or HER2 copy number ≥10 (4 patients, ORR 100%). Median tumour change in size was 42% decrease (range -100% to +53%). Median duration of response was 5.6 (95% confidence interval [CI], 3.8 to 7.3) months. Treatment toxicity was mild with four patients experiencing grade ≥3 toxicity, including fatigue, neuropathy, neutropaenia, urinary tract infection, and pneumonitis.

CONCLUSIONS

Trastuzumab-paclitaxel induces objective tumour responses in 46% of EGFR TKI pretreated patients with an activating EGFR mutation and HER2 expression. The treatment was well tolerated. The relation between response rate and HER2 expression level and copy number suggests effective HER2 targeting by trastuzumab, although the combination with paclitaxel does not allow to determine the relative contribution of the individual drugs in terms of treatment efficacy.

Trastuzumab-induced cardiotoxicity and its risk factors in real-world setting of breast cancer patients

PURPOSE

Cardiotoxicity is the most important side effect of trastuzumab treatment. Heart function monitoring is recommended during the treatment which has led to growing use of resources. The aim of this retrospective study was to determine the frequency and timing of trastuzumab cardiotoxicity and its risk factors in real-world setting.

METHODS

Single institute, retrospective collection of data on HER2+ breast cancer patients (n = 246) was carried out through a pharmacy search for patients who had received trastuzumab in 2006-2014. Clinical and pathological factors, treatment history, EF measurements, cardiac medications, cardiovascular disease history, cardiac symptoms, and survival data were collected from patient records.

RESULTS

32 patients (13%) had EF decline ≥ 10%, eleven (4.5%) had EF decline ≥ 20% within 1 year after trastuzumab initiation, and trastuzumab was discontinued due to suspected cardiotoxicity in six patients (2.4%). 49 patients (19.9%) experienced symptoms related to cardiotoxicity during therapy, which accumulated among those with EF drop. Underlying cardiovascular diseases and multiple (≥ 2) cardiac medications were related to EF drop (≥ 20%) and trastuzumab discontinuation. Majority of EF drops (≥ 10%) and trastuzumab discontinuations were seen within 6months of trastuzumab initiation and recovery of EF drop to < 10% of the baseline was seen in most cases (62.5%). There was no statistically significant difference in the survival of patients according to EF drop.

CONCLUSIONS

Trastuzumab cardiotoxicity seems to accumulate among patients with underlying cardiac conditions. EF monitoring could be targeted to risk groups without compromising of the cardiac health or survival of HER2-positive breast cancer patients.

Anti-podocalyxin antibody exerts antitumor effects via antibody-dependent cellular cytotoxicity in mouse xenograft models of oral squamous cell carcinoma

Podocalyxin (PODXL) overexpression is associated with progression, metastasis, and poor outcomes in cancers. We recently produced the novel anti-PODXL monoclonal antibody (mAb) PcMab-47 (IgG₁, kappa). Herein, we engineered PcMab-47 into 47-mG_2a, a mouse IgG_2a-type mAb, to add antibody-dependent cellular cytotoxicity (ADCC). We further developed 47-mG_2a-f, a core fucose-deficient type of 47-mG_2a to augment its ADCC. Immunohistochemical analysis of oral cancer tissues using PcMab-47 and 47-mG_2a revealed that the latter stained oral squamous cell carcinoma (OSCC) cells in a cytoplasmic pattern at a much lower concentration. PcMab-47 and 47-mG_2a detected PODXL in 163/201 (81.1%) and in 197/201 (98.0%) OSCC samples, respectively. 47-mG_2a-f also detected PODXL in OSCCs at a similar frequency as 47-mG_2a. In vitro analysis revealed that both 47-mG_2a and 47-mG_2a-f exhibited strong complement-dependent cytotoxicity (CDC) against CHO/hPODXL cells. In contrast, 47-mG_2a-f exhibited much stronger ADCC than 47-mG_2a against OSCC cells, indicating that ADCC and CDC of those anti-PODXL mAbs depend on target cells. In vivo analysis revealed that both 47-mG_2a and 47-mG_2a-f exerted antitumor activity in CHO/hPODXL xenograft models at a dose of 100 μg or 500 μg/mouse/week administered twice. 47-mG_2a-f, but not 47-mG_2a, exerted antitumor activity in SAS and HSC-2 xenograft models at a dose of 100 μg/mouse/week administered three times. Although both 47-mG_2a and 47-mG_2a-f exerted antitumor activity in HSC-2 xenograft models at a dose of 500 μg/mouse/week administered twice, 47-mG_2a-f also showed higher antitumor activity than 47-mG_2a. These results suggested that a core fucose-deficient anti-PODXL mAb could be useful for antibody-based therapy against PODXL-expressing OSCCs.

Trastuzumab and Vinorelbine as Highly Effective and Safe Therapy for HER-2-Overexpressing Metastatic Breast Cancer. A Single Institution Experience

Aims and Background

Trastuzumab-based therapy has improved survival of women with human epidermal growth factor receptor 2 (HER2)-overexpressing metastatic breast cancer.

Study Design

From September 2002 to July 2006, 45 women with metastatic breast cancer HER2 3+, or 2+ and positive for HER2 gene amplification, were enrolled in the study and received a combination therapy with vinorelbine, 25 mg/m2 weeks 1 and 2, plus trastuzumab, 4 mg/kg loading dose and then 2 mg/kg weekly, in a three weeks cycle. Eligibility criteria included measurable disease and a baseline ejection fraction ≥50%. Forty-two percent of the patients were not pretreated, whereas 58% had received a previous chemotherapy regimen for metastatic disease, including anthracy-clines and/or taxanes (47%), and trastuzumab plus taxol (11%).

Results

We observed 14 (31%) complete responses and 21 (47%) partial responses, with an overall response rate of 78%. Stable disease >6 months was assessed for 5 (11%) patients with a clinical benefit of 89%. Five (11%) patients progressed. With a median follow-up of 11 months, median time to progression was 9 months and median duration of response was 7.6 months for complete remissions and 4 months for partial remissions. Median survival was 29 months.

Conclusions

In spite of a smaller dose intensity of vinorelbine than previously reported, the regimen evaluated was notably effective in terms of response rate, time to progression and survival, with very mild toxicity.

Circulating Tumor Cells in HER-2 Positive Metastatic Breast Cancer Patients Treated with Trastuzumab and Chemotherapy

The detection of circulating tumor cells (CTCs) in peripheral blood may have important prognostic and predictive implications in breast cancer treatment. A limitation in this field has been the lack of a validated method of accurately measuring CTCs. While sensitivity has improved using RT-PCR, specificity remains a major challenge. The goal of this paper is to present a sensitive and specific methodology of detecting CTCs in women with HER-2-positive metastatic breast cancer, and to examine its role as a marker that tracks disease response during treatment with trastuzumab-containing regimens.

The study included patients with HER-2-positive metastatic breast cancer enrolled on two different clinical protocols using a trastuzumab-containing regimen. Serial CTCs were measured at planned time points and clinical correlations were made. Immunomagnetic selection of circulating epithelial cells was used to address the specificity of tumor cell detection using cytokeratin 19 (CK19). In addition, the extracellular domain of the HER-2 protein (HER-2/ECD) was measured to determine if CTCs detected by CK19 accurately reflect tumor burden.

The presence of CTCs at first restaging was associated with disease progression. We observed an association between CK19 and HER-2/ECD. The association of HER-2/ECD with clinical response followed a similar pattern to that seen with CK19. Finally, the absence of HER-2/ECD at best overall response and a change of HER-2/ECD from positive at baseline to negative at best overall response was associated with favorable treatment response.

Our study supports the prognostic and predictive role of the detection of CTCs in treatment of HER-2-positive metastatic breast cancer patients. The association between CK19 and markers of disease burden is in line with the concept that CTCs may be a reliable measure of tumor cells in the peripheral blood of patients with metastatic breast cancer. The association of CTCs at first restaging with treatment failure indicates that CTCs may have a role as surrogate markers to monitor treatment response.

Lisinopril or Coreg CR in reducing cardiotoxicity in women with breast cancer receiving trastuzumab: A rationale and design of a randomized clinical trial

BACKGROUND

Trastuzumab (TZB) is an established therapy for HER2-positive breast cancer. The use of TZB is commonly associated with cardiotoxicity manifesting as asymptomatic decrease in left ventricular ejection fraction (LVEF) or overt heart failure. Several studies demonstrated favorable effects of angiotensin-converting enzyme (ACE) inhibitors and β-blockers (BBs) in the prevention of chemotherapy-induced cardiotoxicity. We hypothesize that patients, randomized to receive an ACE inhibitor or a BB during trastuzumab therapy for breast cancer, will maintain a higher LVEF than patients randomized to placebo.

METHODS AND RESULTS

We designed a prospective, multicenter, randomized, phase II placebo-controlled clinical trial to evaluate the effects of an ACE inhibitor (lisinopril) and a BB (carvedilol phosphate-extended release) on cardiotoxicity in patients with breast cancer who are receiving adjuvant or neoadjuvant TZB therapy. The primary objectives include (1) comparison of incidence of cardiotoxicity and (2) comparison of LVEF as a continuous variable in between the arms. Cardiotoxicity was defined as an absolute decrease in LVEF from baseline of ≥10% at follow-up or an absolute decrease of ≥5% in LVEF from baseline for individuals with <50% LVEF at follow-up. The target accrual is 468 participants, representing patients both with and without anthracycline exposure. The enrollment is completed. The trial is co-sponsored by University of South Florida and National Cancer Institute. The LVEF is being evaluated by echocardiography or multigated acquisition scan.

CONCLUSIONS

If we can demonstrate that the use of an ACE inhibitor or a BB can reduce the degree of TZB-induced cardiotoxicity, it is hoped that patients will receive complete and uninterrupted TZB therapy for breast cancer without compromising cardiac function.

Safety and efficacy of vinorelbine in combination with pertuzumab and trastuzumab for first-line treatment of patients with HER2-positive locally advanced or metastatic breast cancer: VELVET Cohort 1 final results

BACKGROUND

Pertuzumab, trastuzumab, and docetaxel is standard of care for first-line treatment of HER2-positive metastatic breast cancer (MBC). However, alternative chemotherapy partners are required to align with patient/physician preferences and to increase treatment flexibility. We report VELVET Cohort 1 results in which the efficacy and safety of pertuzumab and trastuzumab, administered sequentially in separate infusions, followed by vinorelbine, were evaluated. Cohort 2, where pertuzumab and trastuzumab were administered in a single infusion, followed by vinorelbine, recruited after Cohort 1 was fully enrolled, will be reported later.

METHODS

In this multicenter, two-cohort, open-label, phase II study, patients with HER2-positive locally advanced or MBC who had not received chemotherapy or biological therapy for their advanced disease received 3-weekly pertuzumab (840 mg loading, 420 mg maintenance doses) and trastuzumab (8 mg/kg loading, 6 mg/kg maintenance doses), followed by vinorelbine (25 mg/m² initial dose, 30-35 mg/m² maintenance doses) on days 1 and 8 or 2 and 9 of each 3-weekly cycle. Study treatment was given until investigator-assessed disease progression or unacceptable toxicity. The primary endpoint was investigator-assessed objective response rate (ORR) in patients with measurable disease at baseline per RECIST v1.1. Secondary endpoints included progression-free survival (PFS) and safety.

RESULTS

Cohort 1 enrolled 106 patients. Investigator-assessed ORR was 74.2% (95% CI 63.8-82.9) in intent-to-treat patients with measurable disease (89/106 [84.0%]). Median PFS was 14.3 months (95% CI 11.2-17.5) in the intent-to-treat population. Treatment was reasonably well tolerated, with no unexpected toxicities. Diarrhea (61/106 patients [57.5%]) and neutropenia (54/106 [50.9%]) were the most common adverse events (AEs); neutropenia (33/106 [31.1%]) and leukopenia (14/106 [13.2%]) were the most common grade ≥3 AEs. Serious AEs were reported in 32/106 (30.2%) patients. AEs led to study drug discontinuation in 36/106 patients (34.0%). Eighteen of 106 patients (17.0%) had AEs suggestive of congestive heart failure; however, there were no confirmed cases.

CONCLUSIONS

The vinorelbine, pertuzumab, and trastuzumab combination is active and reasonably well tolerated. This regimen offers an alternative for patients who cannot receive docetaxel for first-line treatment of HER2-positive locally advanced or MBC.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01565083 , registered on 26 March 2012.

Cutaneous Metastasis due to Breast Cancer in a Patient with Primary Biliary Cirrhosis: A Case Report

Background

Breast cancer is the most common solid tumor to cause cutaneous metastases. These are incurable and the treatment goal is geared toward local control with surgical excision, radiation, and chemotherapy. However, treatment can be challenging in subjects with end-stage liver disease and a multidisciplinary approach is warranted.

Case Report

In this case report, we present a 61-year-old female with primary biliary cirrhosis and human epidermal growth factor-2 (HER-2)-positive breast cancer, who subsequently developed cutaneous metastases. We briefly describe the treatment challenges due to underlying end-stage liver disease, and an exceptional response to trastuzumab and nab-paclitaxel.

Conclusion

A multidisciplinary approach to local control and attenuated doses of nab-paclitaxel and trastuzumab suggest a durable response to HER-2-positive breast cancer with cutaneous metastasis. Subjects with end-stage liver disease pose unique challenges and toxicities, warranting additional research and drug development for less hepatotoxic antineoplastic agents.

Treatment of patients with refractory metastatic cancer according to molecular profiling on tumor tissue in the clinical routine: an interim-analysis of the ONCO-T-PROFILE project

Introduction

Patients with refractory metastatic cancer have been shown to benefit from molecular profiling of tumor tissue. The ONCO-T-PROFILE project was launched in March 2014 at the Innsbruck Medical University. Within 2 years our project aims to recruit 110 patients with stage IV cancer refractory to standard therapy. Our data presented here are based on an interim-analysis.

Methods

Tumor tissue specimens were submitted for molecular profiling to the certified laboratory (Caris Life Science, USA). Druggable tumor targets were selected based on biomarker status to agents with potential clinical benefit. Clinical benefit was defined as a PFS ratio (=PFS upon treatment according to the molecular profile/ PFS upon the last prior therapy) ≥ 1.3.

Results

As of April 2015, tumors from 50 patients have been molecularly profiled and one or more targets were detectable in 48 specimens (98%). So far, 19 (38%) patients have been treated according to their molecular tumor profile. To date, 8 (42%) patients have reached a PFS ratio of ≥ 1.3.

Conclusions

We could show that molecular profiling is feasible in the clinical routine. A proportion of patients might benefit from an individualized treatment approach based on molecular profiling. As a result, we will proceed to enroll patients in ONCO-T-PROFILE.

Phase II study on the efficacy and safety of Lapatinib administered beyond disease progression and combined with vinorelbine in HER-2/neu- positive advanced breast cancer: results of the CECOG LaVie trial

Background

Vinorelbine constitutes effective chemotherapy for metastatic breast cancer (MBC) and acts synergistically with trastuzumab in HER-2/neu positive disease. The present study was set out to evaluate the efficacy and safety of vinorelbine when combined with lapatinib, an anti-HER2 tyrosine-kinase inhibitor, as late-line regimen administered beyond previous disease progression on prior lapatinib in patients with HER-2/neu- positive MBC.

Methods

The CECOG LaVie study was designed as open-labeled, single-arm, multicenter phase II trial. Patients had to be pretreated with lapatinib plus chemotherapy, and received lapatinib at a daily dose of 1250 mg in combination with vinorelbine 20 mg/m² i.v. on days 1 and 8 of a three-week cycle until disease progression, intolerable toxicity or withdrawal of consent. Progression-free survival (PFS) was defined as primary study endpoint; secondary endpoints included overall survival (OS), response rate according to RECIST 1.1, and safety. The study was terminated early due to poor accrual.

Results

A total number of nine patients were included; lapatinib administered beyond disease progression combined with vinorelbine resulted in a median PFS of 7.7 months (95 % CI 0.56-14.91) and a median OS of 23.4 months (95 % CI 16.61–30.13), respectively. Partial remission was seen in one of nine patients, three patients had stable disease of > six months, whereas the remaining five patients had primary disease progression. In two patients, modification of vinorelbine dose due to toxicity became necessary; no dose modification was needed for lapatinib. The majority of reported adverse events (AE) were grade 1 and 2 in severity with diarrhea being the most commonly observed AE

Conclusion

In this heavily pretreated patient population, combination of vinorelbine plus lapatinib showed encouraging activity and was characterized by an acceptable safety profile. Despite the low patient number, lapatinib plus vinorelbine may constitute a potential treatment option in heavily pretreated patients with HER-2/neu-positive MBC previously exposed to lapatinib.

Trial registration

EudraCT number 2009-016826-15, (15. 10.2009)

The Long-HER study: clinical and molecular analysis of patients with HER2+ advanced breast cancer who become long-term survivors with trastuzumab-based therapy

Background

Trastuzumab improves survival outcomes in patients with HER2+ metastatic breast cancer. The Long-Her study was designed to identify clinical and molecular markers that could differentiate long-term survivors from patients having early progression after trastuzumab treatment.

Methods

Data were collected from women with HER2-positive metastatic breast cancer treated with trastuzumab that experienced a response or stable disease during at least 3 years. Patients having a progression in the first year of therapy with trastuzumab were used as a control. Genes related with trastuzumab resistance were identified and investigated for network and gene functional interrelation. Models predicting poor response to trastuzumab were constructed and evaluated. Finally, a mutational status analysis of selected genes was performed in HER2 positive breast cancer samples.

Results

103 patients were registered in the Long-HER study, of whom 71 had obtained a durable complete response. Median age was 58 years. Metastatic disease was diagnosed after a median of 24.7 months since primary diagnosis. Metastases were present in the liver (25%), lungs (25%), bones (23%) and soft tissues (23%), with 20% of patients having multiple locations of metastases. Median duration of response was 55 months. The molecular analysis included 35 patients from the group with complete response and 18 patients in a control poor-response group. Absence of trastuzumab as part of adjuvant therapy was the only clinical factor associated with long-term survival. Gene ontology analysis demonstrated that PI3K pathway was associated with poor response to trastuzumab-based therapy: tumours in the control group usually had four or five alterations in this pathway, whereas tumours in the Long-HER group had two alterations at most.

Conclusions

Trastuzumab may provide a substantial long-term survival benefit in a selected group of patients. Whole genome expression analysis comparing long-term survivors vs. a control group predicted early progression after trastuzumab-based therapy. Multiple alterations in genes related to the PI3K-mTOR pathway seem to be required to confer resistance to this therapy.

The trastuzumab and vinorelbine combination: an alternative to taxane-based chemotherapy for early-stage and locally advanced her2-positive breast cancer

BACKGROUND

Anthracyclines and taxanes have historically constituted the backbone of chemotherapy regimens for patients with breast cancer positive for the human epidermal growth factor receptor 2 (her2). For a subset of patients who categorically refuse alopecia, or for those with a contraindication to those drugs, there is an urgent need to define alternative regimens. Here, we report our institutional experience with trastuzumab and vinorelbine (tv), a combination with good clinical activity and a good side effect profile for patients with her2-positive breast cancer.

METHODS

In a retrospective analysis, outcomes data were extracted for patients receiving tv as their only chemotherapy in the non-metastatic setting at the Jewish General Hospital. For the most part, tv was administered weekly for 6 months, followed by trastuzumab for 6 months.

RESULTS

The analysis identified 46 patients (mean age: 64 years) who received tv between 2003 and 2012 (n = 36 adjuvant, n = 10 neoadjuvant). Of the patients in the adjuvant group, 81% had stage i disease. In the neoadjuvant group, 3 patients experienced a complete pathologic response. Only 1 patient experienced local recurrence after a short course (3 months) of adjuvant tv. Overall survival and breast cancer-specific survival were 94% and 98% respectively at a median 5 years of follow-up. Febrile neutropenia-induced sepsis resulted in the death of 1 patient with significant medical comorbidities; 2 other patients died of comorbidities unrelated to their cancer or treatment. Grades 3 or 4 adverse events included neutropenia (23%), febrile neutropenia (10%), fatigue (2%), and anemia (2%).

CONCLUSIONS

For patients with non-metastatic breast cancer refusing alopecia, or for patients who are not candidates for standard chemotherapy, tv is a reasonable alternative to standard adjuvant chemotherapy.

Brain metastases in HER2-positive metastatic breast cancer patients who received chemotherapy with or without trastuzumab

OBJECTIVE

The aim of this study was to assess whether trastuzumab usage is a risk factor for the development of brain metastasis (BM) in human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) and factors affecting survival after development of BM.

MATERIALS AND METHODS

One hundred thirty-two patients treated with (treatment group) or without trastuzumab (control group) with brain metastasis were retrospectively analyzed.

RESULTS

Ninety of the 132 HER2-positive MBC patients were in the treatment group and 42 were in the control group. BM was significantly increased in patients who were treated with trastuzumab in two or more lines (58.5 vs 24.1 %, p < 0.001). Trastuzumab and lapatinib usage after BM and age were independent prognostic factors for overall survival in univariate and multivariate analysis.

CONCLUSION

The risk for BM was increased in patients who were treated with trastuzumab in two or more lines. Using trastuzumab and lapatinib after BM and age were independent prognostic factors for time to death from BM.

Phase II study of lapatinib in combination with vinorelbine, as first or second-line therapy in women with HER2 overexpressing metastatic breast cancer

Background

Lapatinib in combination with capecitabine is approved for the treatment of patients with advanced or metastatic breast cancer whose tumors overexpress the human epidermal growth factor receptor 2 (HER2) and who have received prior therapy including an anthracycline, a taxane, and trastuzumab. Based on our phase I trial, we conducted a single arm, multicenter phase II study of lapatinib in combination with vinorelbine.

Patient and methods

Women with HER2-positive advanced breast cancer, who had received up to one prior regimen for metastatic disease, were eligible. Prior trastuzumab was allowed. Patients received daily lapatinib 1500 mg orally and vinorelbine 20 mg/m² intravenously on days 1, 8 and 15 of a 28-day cycle. The primary endpoint was overall response rate (ORR).

Results

Forty-four patients received the combination treatment, including 48% as second-line therapy. The ORR was 41% (95% confidence interval [CI] 26–55%), including 9% with a complete response. Median progression-free survival was 24.1 weeks (95% CI 17–37 weeks) and median duration of response was 32 weeks (95% CI 18–42 weeks). Nearly 80% of patients did not require a dose reduction in lapatinib, although most patients required one dose reduction of vinorelbine secondary to neutropenia. The most common toxicities were grade 1 and 2 diarrhea, nausea, fatigue and rash, and grade 3 and 4 neutropenia. One case of grade 3 asymptomatic decreased left ventricular ejection fraction event was reported.

Conclusion

The combination of lapatinib and vinorelbine was active, feasible and well tolerated in patients with HER2-positive advanced breast cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/2193-1801-3-108) contains supplementary material, which is available to authorized users.

[An efficient method for producing monoclonal antibodies against multi-pass membrane proteins]

Antibodies have greatly contributed to the development of medical science and pharmacology, because of their high specificity. The cell fusion method has developed monoclonal antibodies (mAb) technology, such that massive amounts of mAb with a uniform structure can be produced. Although mAb have been produced against many proteins so far, the production of mAb against multi-pass transmembrane proteins, such as G-protein coupled receptor (GPCR) and various transporter proteins has been extremely difficult. The complicated structures, poorly extracellular regions, and high hydrophobicity of multiple-transmembrane proteins make it difficult to produce mAb against them. Production of mAb that recognize the extracellular region of living cells is thought to be important in determining the ability of a protein. Based on these findings, we tried to produce mAb against a multi-pass transmembrane transporter using green fluorescent protein (GFP)-fused full-length target proteins as immunogens. Furthermore, the immunizing method has proved to be important in generating functional mAb. We succeeded in producing functional mAb that react against the extracellular region of a 12-pass transmembrane transporter in a living cell. Based on this success, we began to produce mAb against seven-transmembrane GPCR. In this symposium, we report on the results of producing mAb against S1P receptors, a type of GPCR.

A phase II study of bevacizumab in combination with vinorelbine and trastuzumab in HER2-positive metastatic breast cancer

We aimed to evaluate the efficacy and feasibility of combining trastuzumab/vinorelbine with bevacizumab in patients with first-or second-line HER2-positive, metastatic breast cancer (MBC). Eligible patients had HER2-positive measureable MBC, with no more than one prior line of chemotherapy, and were treated with trastuzumab (4 mg/kg × 2 mg/kg weekly thereafter), vinorelbine (25 mg/m(2) weekly), and bevacizumab (10 mg/kg every 2 weeks). Co-primary endpoints were (a) the proportion of patients alive and progression-free at 1 year and (b) safety profile/feasibility. Feasibility was defined as a rate of grade 3/4 non-hematologic toxicity attributable to protocol-based therapy <20 %. Twenty-nine patients were enrolled (n = 22 first-line, n = 7 second-line). Median age was 48 years (range 37-68). The median number of cycles received was 8 (1-23) and median duration on treatment was 7.4 months (range 1-22). The study was closed early due to higher-than-expected rates of grade 3/4 non-hematologic toxicities, with 50 events in 20 patients. A total of six patients (21 %) were taken off study for treatment-related toxicity. Most common treatment-related toxicities included fatigue (n = 7), febrile neutropenia (n = 4), and headache (n = 3). At 1 year, 8/22 first-line (36 %) and 2/7 second-line (29 %) patients were alive and progression-free. Median PFS was 9.9 months and 7.8 months in the first- and second-line cohorts, respectively. Objective responses were observed in 16/22 (73 %) and 5/7 (71 %) patients in the first- and second-line settings. Although the combination of vinorelbine, trastuzumab, and bevacizumab showed notable activity in HER2-positive MBC, the proportion of first-line patients alive and progression-free at 1 year was deemed unlikely to reach the pre-defined threshold for declaring success. Additionally, unacceptable toxicity was observed, at rates greater than previously reported with vinorelbine/trastuzumab or vinorelbine/bevacizumab doublet combinations.

Engineering a single ubiquitin ligase for the selective degradation of all activated ErbB receptor tyrosine kinases

Interrogating specific cellular activities often entails the dissection of posttranslational modifications or functional redundancy conferred by protein families, which demands more sophisticated research tools than simply eliminating a specific gene product by gene targeting or RNA interference. We have developed a novel methodology that involves engineering a single SCF(βTrCP)-based ubiquitin ligase that is capable of not only simultaneously targeting the entire family of ErbB receptor tyrosine kinases for ubiquitination and degradation, but also selectively recruiting only activated ErbBs. The engineered SCF(βTrCP) ubiquitin ligase effectively blocked ErbB signaling and attenuated oncogenicity in breast cancer cells, yet had little effect on the survival and growth of non-cancerous breast epithelial cells. Therefore, engineering ubiquitin ligases offers a simple research tool to dissect the specific traits of tumorigenic protein families, and provides a rapid and feasible means to expand the dimensionality of drug discovery by assessing protein families or posttranslational modifications as potential drug targets.

Clinical outcomes and treatment practice patterns of patients with HER2-positive metastatic breast cancer in the post-trastuzumab era

BACKGROUND

Trastuzumab is associated with improvements in overall survival (OS) among patients with HER2-positive metastatic breast cancer (MBC); however disease course and patterns of care in individual patients are highly variable.

METHODS

113 HER2-positive patients diagnosed with MBC from 1999 to 2005 who received trastuzumab-based therapy were retrospectively identified to allow for a minimum of 5 years of follow-up time. Median OS and median duration of therapy were determined using Kaplan-Meier methodology and group comparisons were based on the log-rank test. Hazard ratios (HR) were obtained using a Cox proportional hazards model.

RESULTS

Median OS was 3.5 years (95% CI 3.0-4.4) from time of initiation of first therapy in the metastatic setting. On univariate analysis, central nervous system (CNS) disease at first recurrence was associated with a shorter OS compared with liver and/or lung metastases or other sites (CNS: 1.9 years CI 0.1-5.9, liver/lung: 3.2 years CI 2.5-4.2, other: 4.6 years CI 2.7-8.0; p = 0.05), however, this was not predictive of survival outcome in multivariate analysis. CNS metastases developed in 62 (55%) patients by the time of death or last follow-up. Median duration of therapy was similar up to 6 lines of treatment, and ranged from 5.2 months to 7.2 months.

CONCLUSIONS

The natural history of HER2-positive MBC has evolved with trastuzumab-based therapy with median OS now exceeding 3 years. CNS disease is a major problem with continued risk of CNS progression over time. Patients demonstrate clinical benefit to multiple lines of HER2-directed therapy.

Treating breast cancer in the 21st century: emerging biological therapies

For many years, the medical treatment of breast cancer was reliant solely on cytotoxic chemotherapy. However, over the past twenty years, treatment has evolved to a more target-directed approach. We now employ tailored therapy based on the presence or absence of receptors for estrogen, progesterone, and human epidermal growth factor 2 (HER2). We expect this trend to continue, as agents that use novel approaches to target HER2, as well as targeting different portions of the HER signaling pathway, are in various stages of development. Notably, pertuzumab, a humanized monoclonal antibody that binds to a different domain of the extracellular portion of the HER2 receptor than trastuzumab, was recently approved for use, as was lapatinib, a small-molecule tyrosine kinase inhibitor. Patients with triple negative breast cancer, particularly those with the BRCA mutation, have more limited treatment options and carry a worse prognosis than those who are hormone receptor positive. However, recent data has shown that PARP inhibitors may have significant anti-tumor effect in those with this subtype of breast cancer. Novel agents that inhibit mTOR, PI3K, the insulin-like growth factor, heat shock protein 90, and histone deacetylase have shown promise in phase I-III trials and offer exciting new possibilities for the treatment of this often fatal disease. As we are presented with an ever increasing number of treatment options, the timing and combinations of therapeutic agents used becomes ever more complex in the age of personalized care, but we are hopeful that ultimately this will lead to improved patient outcomes.

Fluid biopsy for solid tumors: a patient's companion for lifelong characterization of their disease

Cancer is currently diagnosed and treated based on the results of a tissue biopsy of the primary tumor or a metastasis using invasive techniques such as surgical resection or needle biopsy. New technology for retrieving cancer cells from the circulation, developed in the last 5 years, has made it possible to obtain a 'fluid biopsy' from the bloodstream without the need for an invasive procedure. This technological development makes it possible to diagnose and manage cancer from a blood test rather than from a traditional biopsy. It also allows the repeated sampling of cancer cells from a patient, making it possible, in a practical manner, to interrogate the disease repeatedly in order to understand the mechanisms by which cancer cells evolve within a given individual. The ability to obtain cancer cells repeatedly also has the potential to substantially advance drug development by enabling early ex vivo validation of both targets and early-stage compounds, as well as creating new efficiencies in the drug development process during clinical trials.

Improving survival and limiting toxicity: latest advances in treating human epidermal growth factor receptor 2 overexpressing breast cancer

In recent years, new strategies for the treatment of breast cancer have focused on extensive target identification and understanding the expression, regulation and function of critical signaling pathways involved in breast cancer initiation and progression. This has led to significant progress in developing and understanding human epidermal growth factor receptor 2 (HER2)-targeted therapies, which in turn, has translated into significant increases in median survival for patients with HER2-overexpressing breast cancer. It is becoming increasingly difficult to make specific recommendations for the optimal treatment of HER2-overexpressing breast cancer since the field is evolving so rapidly. However, despite the many randomized trials that have been undertaken showing improvement in survival, the current standard treatment for HER2-overexpressing breast cancer continues to revolve around the addition of chemotherapy to a HER2-targeted agent, which in turn, carries substantial toxicities. This article reviews agents that have recently been investigated to treat HER2-overexpressing breast cancers. The goal is ultimately to increase the magnitude and duration of response to trastuzumab-based treatment while minimizing toxicity. Studies addressing length of therapy duration, the superiority and side-effect profile of the different biological drug combinations, and determination of biomarkers of resistance to HER2 therapy will be instrumental in decreasing morbidity and mortality for patients with HER2-overexpressing breast cancer.

Phase II interventional study (N0337) of capecitabine in combination with vinorelbine and trastuzumab for first- or second-line treatment of HER2-positive metastatic breast cancer: a north central cancer treatment group trial

BACKGROUND

We conducted a multiinstitutional phase II study of capecitabine in combination with vinorelbine and trastuzumab in patients eligible to receive first- or second-line treatment for human epidermal growth factor receptor type 2 (HER2)-positive (HER2(+)) metastatic breast cancer (MBC).

PATIENTS AND METHODS

The study was designed to test that the true confirmed response rate (CRR) was at most 45% vs. a true CRR of at least 65%. Between March 2005 and June 2008, eligible patients received capecitabine 825 mg/m² orally on days 1 to 14, vinorelbine 25 mg/m² intravenously on days 1 and 8 every 3 weeks, and trastuzumab 8 mg/kg intravenously on day 1 week 1 and 6 mg/kg every 3 weeks. The main outcome measure was CRR.

RESULTS

Of 47 women accrued, 45 were evaluable. This design required at least 25 confirmed responses in the 45 evaluable patients for the treatment to be considered promising. Thirty women (67%) achieved a confirmed response; 25 women (56%) had a confirmed partial response (PR); 5 women (11%) had confirmed complete responses (CRs). Median progression-free survival (PFS) was 11.3 months (95% confidence interval [CI], 8.4-16.7 months). Median overall survival was 28.5 months (95% CI, 24.8-36.4 months).

CONCLUSIONS

This triplet combination demonstrated promising activity in patients with HER2(+) MBC.

Modulation of MicroRNA-194 and cell migration by HER2-targeting trastuzumab in breast cancer

Trastuzumab, a humanized monoclonal antibody directed against the extracellular domain of the HER2 oncoprotein, can effectively target HER2-positive breast cancer through several mechanisms. Although the effects of trastuzumab on cancer cell proliferation, angiogenesis and apoptosis have been investigated in depth, the effect of trastuzumab on microRNA (miRNA) has not been extensively studied. We have performed miRNA microarray profiling before and after trastuzumab treatment in SKBr3 and BT474 human breast cancer cells that overexpress HER2. We found that trastuzumab treatment of SKBr3 cells significantly decreased five miRNAs and increased three others, whereas treatment of BT474 cells significantly decreased two miRNAs and increased nine. The only change in miRNA expression observed in both cell lines following trastuzumab treatment was upregulation of miRNA-194 (miR-194) that was further validated in vitro and in vivo. Forced expression of miR-194 in breast cancer cells that overexpress HER2 produced no effect on apoptosis, modest inhibition of proliferation, significant inhibition of cell migration/invasion in vitro and significant inhibition of xenograft growth in vivo. Conversely, knockdown of miR-194 promoted cell migration. Increased miR-194 expression markedly reduced levels of the cytoskeletal protein talin2 and specifically inhibited luciferase reporter activity of a talin2 wild-type 3'-untranslated region, but not that of a mutant reporter, indicating that talin2 is a direct downstream target of miR-194. Trastuzumab treatment inhibited breast cancer cell migration and reduced talin2 expression in vitro and in vivo. Knockdown of talin2 inhibited cell migration/invasion. Knockdown of trastuzumab-induced miR-194 expression with a miR-194 inhibitor compromised trastuzumab-inhibited cell migration in HER2-overexpressing breast cancer cells. Consequently, trastuzumab treatment upregulates miR-194 expression and may exert its cell migration-inhibitory effect through miR-194-mediated downregulation of cytoskeleton protein talin2 in HER2-overexpressing human breast cancer cells.

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

PURPOSE

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 AND METHODS

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.

RESULTS

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.

CONCLUSION

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.

Trastuzumab for HER2-Positive Metastatic Breast Cancer: Clinical and Economic Considerations

Trastuzumab is a recombinant humanized monoclonal antibody that selectively targets the extra-cellular domain of the HER2 receptor. It was approved by the FDA in September 1998 as the first targeted therapy for HER2-positive metastatic breast cancer, and has since led to significant improvements in the overall prognosis for patients with HER2-positive metastatic disease. The favourable benefit/risk profile associated with palliative trastuzumab has been demonstrated in a number of clinical trials that examined trastusumab as monotherapy or in combination with chemotherapy, endocrine therapy and other HER2 targeted agents. The clinical benefits of trastuzumab, however should also be examined within the context of its significant drug acquisition costs. This review highlights the significant findings from the landmark clinical trials of trastuzumab for metastatic HER2-positive breast cancer, and the potential “value for money” associated with its use in clinical practice.

Trastuzumab and Gemcitabine in Pretreated HER2 Overexpressing Metastatic Breast Cancer Patients: Retrospective Analysis of Our Series

Trastuzumab-based regimes improved clinical outcome in women with overexpressing HER2 metastatic breast cancer, mainly due to the availability of different combination therapies, clinically active and well tolerated. In this study we retrospectively evaluated clinical activity and toxicity of trastuzuamb plus gemcitabine regimen in heavily pretreated HER2 positive metastatic breast cancer patients. Although the observed population was heavily pretreated, the evaluated regimen was notably effective in terms of response rate, time to progression and survival, with very mild toxicity. These data suggest that in over expressing HER2 metastatic breast cancer patients, sequential trastuzumab based chemotherapeutic regimens can achieve good response rate with prolonged TTP in responding patients, even after other target therapy such as lapatinib based combinations.

Targeted therapy in the management of advanced gastric cancer: are we making progress in the era of personalized medicine?

BACKGROUND

Gastric cancer is one of the leading causes of cancer death. With greater understanding of the molecular basis of carcinogenesis, targeted agents have led to a modest improvement in the outcome of advanced gastric cancer (AGC) patients.

METHODS AND RESULTS

We conducted an overview of the published evidence regarding the use of targeted therapy in AGC patients. Thus far, the human epidermal growth factor receptor (HER) pathway, angiogenic pathway, and phosphatidylinositol-3-kinase (PI3K)-Akt-mammalian target of rapamycin pathway have emerged as potential avenues for targeted therapy in AGC patients. The promising efficacy results of the Trastuzumab for Gastric Cancer trial led to the approved use of trastuzumab-based therapy as first-line treatment for patients with HER-2+ AGC. On the other hand, the Avastin® in Gastric Cancer trial evaluating bevacizumab in combination with chemotherapy did not meet its primary endpoint of a longer overall survival duration despite a significantly higher response rate and longer progression-free survival time in patients in the bevacizumab arm. Phase III data are awaited for other targeted agents, including cetuximab, panitumumab, lapatinib, and everolimus.

CONCLUSION

Recent progress in targeted therapy development for AGC has been modest. Further improvement in the outcome of AGC patients will depend on the identification of biomarkers in different patient populations to facilitate the understanding of gastric carcinogenesis, combining different targeted agents with chemotherapy, and unraveling new molecular targets for therapeutic intervention.

Phase I study of lapatinib plus vinorelbine in patients with locally advanced or metastatic breast cancer overexpressing HER2

Background:

To determine the recommended doses of lapatinib (LPT) combined with vinorelbine (VNR) in women with human epidermal growth factor receptor 2-overexpressing advanced breast cancer pretreated with trastuzumab.

Methods:

In this phase I study, women were treated with oral daily LPT and i.v. VNR infused on days 1 and 8 every 3 weeks. Dose levels (DL) of LPT (mg)/VNR (mg m⁻²) ranged from 750/20 to 1250/30. The primary end point was feasibility based on maximal tolerated dose (MTD) and maximum administered dose (MAD). Pharmacokinetic interactions were investigated.

Results:

Of 33 patients included, 29 were evaluable. Two DLT occurred at DL4 (1000/25) meeting the MAD criteria. Despite an additional intermediate DL3′ (1250/22.5), MTD was reached at DL3 (1000/22.5). Grade 3–4 neutropenia was the most common toxicity (34% and 38% of patients, respectively). Other significant toxicities included grade 3–4 diarrhoea (3% each), and grade 3 asthenia (10%). Although not statistically significant, LPT (at 1000 or 1250 mg) decreased the VNR clearance by 30–40% compared with DL1.

Conclusion:

The MTD LPT 1000 mg/VNR 22.5 mg m⁻² (DL3) is recommended for additional development. Pharmacokinetic interactions might increase the exposure to VNR and consequently alter the hematological tolerance.

Predicting survival in women with breast cancer and brain metastasis: a nomogram outperforms current survival prediction models

BACKGROUND

Brain metastases (BMs) are a common occurrence in patients with breast cancer, and accurately predicting survival in these patients is critical to appropriate management. A survival nomogram for breast cancer patients with BM was constructed, and its performance is compared to current predictive models of survival.

METHODS

A Cox proportional hazards regression with a nomogram representation was used to model survival in a population of 261 women with breast cancer and BMs treated from 1999 to 2008. The model was validated internally by 10-fold cross-validation and bootstrapping, and concordance (c) indices were calculated. The predictive performance of the nomogram described here is compared to current prognostic models, including recursive partitioning analysis, graded prognostic assessment, and diagnosis-specific graded prognostic assessment.

RESULTS

The c-index for the model described here was 0.67. It outperformed recursive partitioning analysis, graded prognostic assessment, and diagnosis-specific graded prognostic assessment, based on c-index comparisons.

CONCLUSIONS

The nomogram described here outperformed current strategies for survival prediction in breast cancer patients with BMs. Two additional advantages of this nomogram are its ability to predict individualized, 1-, 3-, and 5-year survival for novel patients and its straightforward representations of the relative effects of each of 9 covariates on neurologic survival. This represents a potentially valuable alternative to current models of survival prediction in this patient population.

Study of compliance with prescription information sheet of trastuzumab prescriptions in a tertiary level hospital

INTRODUCTION

This study compares trastuzumab's actual conditions of use in clinical practice with those officially described on its summary of product characteristics. We also measure the cost associated with its use.

METHODS

Observational study of the prescription/indication of trastuzumab in a tertiary hospital from January 2006 to 31 December 2007. We analysed whether trastuzumab use in clinical practice complied with its summary of product characteristics, concerning the following: HER2 over expression, indication (breast cancer), treatment plan, line of treatment, dosage, frequency and number of cycles. To measure cost, we calculated the total number of milligrams used and then multiplied it by the laboratory's sale price per milligram plus VAT.

RESULTS

All patients (n=77) used trastuzumab for breast cancer. Sixty-two point two percent of patients presented with HER2+++ over expression. Twenty-nine treatment plans were used, that were not authorised on the summary of product characteristics. The total trastuzumab cost during the study period was €1537 622.73.

CONCLUSIONS

Although trastuzumab is always used for breast cancer, it is used in conditions other than those described on its summary of product characteristics, both for HER2 over expression and treatment plans.

Trastuzumab emtansine in human epidermal growth factor receptor 2-positive breast cancer: a review

PURPOSE OF REVIEW

In this review, we aim to update the clinical data of trastuzumab-DM1 (T-DM1) in terms of safety and efficacy, and describe ongoing and future trials evaluating its potential role in the management of patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer.

RECENT FINDINGS

Trastuzumab emtansine (T-DM1) is an antibody drug conjugate that optimizes delivery of chemotherapy with an anti-HER2 monoclonal antibody. As a conjugate, T-DM1's systemic side effects are significantly minimized due to its targeted delivery by trastuzumab to HER2-positive cells. Phase I and II studies show that the maximum tolerated dose, and thus the recommended dose for T-DM1, is 3.6  mg/kg given intravenously every 3 weeks. Single arm phase Ib/II, II and a randomized phase II first-line study of T-DM1 versus the combination of trastuzumab + docetaxel all showed improved tolerability, and at least equivalent efficacy, compared with our current standard of care. Two randomized phase III registration studies are now active, evaluating this agent in the refractory and first-line HER2-positive settings.

SUMMARY

T-DM1 has been shown to be a very promising agent for the targeted delivery of chemotherapy and anti-HER2 monoclonal antibody therapy for patients with metastatic, HER2-positive breast cancer. T-DM1 will likely play a role in the management of patients with advanced and early stage HER2-positive breast cancer, but this awaits further study.

Molecular aspects of breast cancer metastasis to the brain

Our knowledge of the biology underlying the development of brain metastases (BM) from breast cancer has improved over the last decade due to large clinical epidemiological studies, animal models of metastasis, and the use of high-resolution gene expression profiling technologies. However, there are still major gaps in our understanding of the mechanisms utilized by breast cancer cells to colonize the brain microenvironment, thus our arsenal of therapies remains relatively nonspecific, and the prognosis for breast cancer patients with BM remains poor. Additional insights into these mechanisms are necessary to facilitate the development of new preventive and curative therapeutic regimens to block this fatal disease. This paper aims to provide a general overview for the readers of what has been achieved in this field of research and its translation into clinical practice to date and to highlight exciting new areas of research that promise to inform the development of new targeted therapies for BM.

Evolving strategies for overcoming resistance to HER2-directed therapy: targeting the PI3K/Akt/mTOR pathway

Human epidermal growth factor receptor 2-positive (HER2+) breast cancers, which account for 25%-30% of breast cancers, are characterized by an aggressive course and a high propensity for recurrence in the 4 years following diagnosis. The use of trastuzumab-based chemotherapy in the adjuvant setting has markedly improved the outcome for patients with early stage HER2+ breast cancer. Likewise the use of trastuzumab in combination with chemotherapy in patients with metastatic HER2+ breast cancers has prolonged survival, with current expected median survival of about 3 years. Despite these major improvements in outcome, approximately 10% of patients develop a distant recurrence following adjuvant trastuzumab-based chemotherapy, and all patients with metastatic disease eventually develop disease progression. Known mechanisms of resistance to trastuzumab include increased signaling through upstream growth factors, phosphatase and tensin (PTEN) deficiency and alterations of the HER2 receptor. Many of these mechanisms are being targeted in the clinic in an attempt to improve outcome for patients with HER2+ breast cancers. The phosphatidylinositol 3-kinase (PI3K) pathway plays a key role in trastuzumab-resistance, through these and other mechanisms, and represents a logical target for drug development for trastuzumab-resistant breast cancers. The use of mammalian target of rapamycin (mTOR) inhibition has been demonstrated to potentially reverse resistance to trastuzumab in patients with HER2+, metastatic breast cancers. Phase I and II trials have produced encouraging results when the mTOR inhibitor, everolimus, was combined with trastuzumab with or without chemotherapy, in patients with trastuzumab-resistant HER2+ metastatic breast cancer. These results are being confirmed in ongoing phase III trials in the first-line and trastuzumab-resistant settings. The mechanism of how mTOR inhibitors reverse resistance to trastuzumab remains largely unexplained. Other agents targeting the PI3K pathway in trastuzumab-resistant breast cancers are in early phase clinical trials.

Post-marketing safety evaluation of S-1 in patients with inoperable or recurrent breast cancer: especially in patients treated with S-1 + trastuzumab

Objective

The purpose of this study was to assess the safety of S-1 in Japanese in inoperable or recurrent breast cancer patients.

Methods

A prospective post-marketing surveillance was performed at 313 sites in Japan in patients with inoperable or recurrent breast cancer treated with S-1. We examined 1361 patients between January 2006 and December 2007 with regard to the incidence of adverse drug reactions graded by the Common Terminology Criteria for Adverse Events (CTCAE), version 3.0.

Results

At least one adverse drug reaction was encountered by 858 patients, with an overall incidence of 63.0% (858/1361). The incidence of Grade 3 or higher adverse drug reactions in a descending order was 14.7% (200/1361). In this study, the most common combination drug was trastuzumab. The overall incidence of adverse drug reactions was 63.5% (431/679 patients) in patients treated with S-1 alone, and 55.9% (66/118 patients) in patients treated with S-1 + trastuzumab.

Conclusions

Monotherapy with S-1 or combination therapy with S-1 + trastuzumab was well tolerated for inoperable or recurrent breast cancer patients.

Phase I study of continuous and intermittent schedules of lapatinib in combination with vinorelbine in solid tumors

BACKGROUND

Chemotherapy in combination with small-molecule epidermal growth factor receptor inhibitors has yielded inconsistent results. Based on preclinical models, we conducted a phase I trial of two schedules of lapatinib and vinorelbine.

PATIENT AND METHODS

Patients had advanced solid tumors and up to two prior chemotherapeutic regimens. Patients were enrolled on two dose-escalating schedules of lapatinib, continuous (arm A) or intermittent (arm B), with vinorelbine on days 1, 8, and 15 of a 28-day cycle. Tumors from a subset of patients were evaluated for gene mutations and expression of targets of interest.

RESULTS

Fifty-one patients were treated. The most common grade 3/4 toxic effects included leukopenia, neutropenia, and fatigue. Dose-limiting toxic effects were grade 3 infection, febrile neutropenia, and diarrhea (arm A) and bone pain and fatigue (arm B). The maximum tolerated dose was vinorelbine 20 mg/m(2) weekly and lapatinib 1500 mg daily (arm A) and vinorelbine 25 mg/m(2) weekly and lapatinib 1500 mg intermittently (arm B). One patient on each arm had a complete response; both had human epidermal growth factor receptor 2-positive breast cancer. In a subset of patients, lack of tumor PTEN expression correlated with a shorter time to progression.

CONCLUSION

In an unselected population, two schedules of lapatinib and vinorelbine were feasible and well tolerated.

Trastuzumab (herceptin) targets gastric cancer stem cells characterized by CD90 phenotype

Identification and characterization of cancer stem cells (CSCs) in gastric cancer are difficult owing to the lack of specific markers and consensus methods. In this study, we show that cells with the CD90 surface marker in gastric tumors could be enriched under non-adherent, serum-free and sphere-forming conditions. These CD90(+) cells possess a higher ability to initiate tumor in vivo and could re-establish the cellular hierarchy of tumors from single-cell implantation, demonstrating their self-renewal properties. Interestingly, higher proportion of CD90(+) cells correlates with higher in vivo tumorigenicity of gastric primary tumor models. In addition, it was found that ERBB2 was overexpressed in about 25% of the gastric primary tumor models, which correlates with the higher level of CD90 expression in these tumors. Trastuzumab (humanized anti-ERBB2 antibody) treatment of high-tumorigenic gastric primary tumor models could reduce the CD90(+) population in tumor mass and suppress tumor growth when combined with traditional chemotherapy. Moreover, tumorigenicity of tumor cells could also be suppressed when trastuzumab treatment starts at the same time as cell implantation. Therefore, we have identified a CSC population in gastric primary tumors characterized by their CD90 phenotype. The finding that trastuzumab targets the CSC population in gastric tumors suggests that ERBB2 signaling has a role in maintaining CSC populations, thus contributing to carcinogenesis and tumor invasion. In conclusion, the results from this study provide new insights into the gastric tumorigenic process and offer potential implications for the development of anticancer drugs as well as therapeutic treatment of gastric cancers.

In vivo activity of novel anti-ErbB2 antibody chA21 alone and with Paclitaxel or Trastuzumab in breast and ovarian cancer xenograft models

It was well studied that ErbB2 (HER2/p185(her2/neu)) overexpression in human malignant cancers correlates with poor prognosis and chemo-resistance. Although Trastuzumab (Herceptin) has been widely used in patients with ErbB2-overexpressing metastatic breast cancer, many patients either do not respond to Trastuzumab therapy or progress within 1 year of initiating Trastuzumab treatment. Previously, we reported a novel tumor-inhibitory antibody chA21, which recognized ErbB2 extracellular domain with an epitope distinct from other tumor-inhibitory anti-ErbB2 antibodies. Here, we report that chA21 combined with Paclitaxel or Trastuzumab significantly enhances the tumor-inhibition effects on ErbB2-overexpressing breast and ovarian cancer in xenograft mice. Moreover, the study reveals that the effects by chA21 to cause an enhanced inhibition on cancer cell proliferation and angiogenesis was highly associated with the intrinsic ability of chA21 to down-regulate ErbB2 receptor, inhibit downstream MAPK and PI3K-AKT signal transduction and activate natural killer cells. Our findings show that chA21 may represent a unique anti-ErbB2 antibody with potentials as therapeutic candidate alone or combination with other anti-ErbB2 reagents in cancer therapy.