Vinorelbine-based salvage therapy in HER2-positive metastatic breast cancer patients progressing during trastuzumab-containing regimens: a retrospective study

Use of Trastuzumab in HER2-positive Metastatic Breast Cancer beyond Disease Progression: A Systematic Review of Published Studies

Aims and background

Trastuzumab, a humanized monoclonal antibody directed against the extracellular domain of ErbB, has determined clinical benefit for women affected by metastatic or early stage HER2-positive breast cancer and never previously treated with trastuzumab. Trastuzumab is generally used as first-line treatment of HER2+ metastatic breast cancer and is currently administered beyond progression even without clear evidence supporting such clinical practice. In fact, HER2-positive metastatic breast cancer has a high risk of progressing after first-line therapy, and second-line treatments vary. The aim of the study was to investigate by a systematic review the efficacy of trastuzumab-based treatments beyond progression in HER2-positive metastatic breast cancer.

Materials and methods

We performed a systematic review using Medline, Embase and Cochrane Library data bases and publications in principal meetings or congresses of oncology in Europe and America until September 2008. The main selection criterium was the reporting of time to progression, calculated from the start of each trastuzumab-based therapy to the date of progressive disease or death.

Results

Twelve studies were selected that included a total of 516 patients. The weighted mean time to progression was 23.66 weeks (standard deviation, 4.37) and the median was 26 weeks (range, 13–39). Interestingly, combined trastuzumab plus vinorelbine treatment showed a lower mean and median time to progression (20.59 and 19.57 weeks, respectively), whereas trastuzumab plus capecitabine yielded a mean time to progression of 30.33 weeks.

Conclusions

The added value of the present study has been to provide a quantitative summary measure of time to progression which can be used for comparisons between current and future available regimens.

Efficacy and safety of trastuzumab combined with chemotherapy for first-line treatment and beyond progression of HER2-overexpressing advanced breast cancer

Objective

To observe the efficacy and safety of trastuzumab combined with chemotherapy in patients with human epidermal growth factor receptor 2 (HER2)-overexpressing advanced breast cancer.

Methods

A total of 90 patients with HER2-overexpressing advanced breast cancer were enrolled in this study. All patients were diagnosed with ductal invasive breast cancer by pathological analysis, and were aged between 31–73 years with a median of 51 years. HER2-positivity was defined as 3(+) staining in immunochemistry or amplification of fluorescence in situ hybridization (FISH, ratio ≥2.0). Trastuzumab was administered in combination with chemotherapy as first-line treatment and beyond progression as a secondline, third-line, and above treatment in 90, 34, 14, and 6 patients, respectively. The chemotherapy regimen was given according to normal clinical practice. The response rate was evaluated every two cycles, and the primary endpoints were progression-free survival (PFS) and overall survival (OS). Survival curves were estimated by using Kaplan-Meier graphs and were compared by using log-rank test statistics. Multivariate analysis was done using Cox’s proportional hazards regression model, and the level of significance was P<0.05.

Results

All 90 patients received at least one dose of trastuzumab, and efficacy could be evaluated in 85 patients. The median follow-up was 50 months. In total, 72 (80.00%) patients had visceral metastasis, and 43 (47.78%) patients had progressed after one or more extensive chemotherapy regimens for metastatic diseases. The median PFS for first-line trastuzumab was 10 months (range, 2–59 months), and the median OS after metastasis or initially local advanced disease was 22 months (range, 2–116 months).

Conclusions

Trastuzumab combined with chemotherapy was active and well-tolerated as a first-line treatment and even beyond progression in HER2-overexpressing advanced breast cancer as a second-line or third-line treatment. However, its efficacy is certainly less beyond this point.

Vinorelbine with or without Trastuzumab in Metastatic Breast Cancer: A Retrospective Single Institution Series

Background. We report our experience with vinorelbine, a widely used chemotherapeutic, in unselected metastatic breast cancer patients treated in clinical routine. Patients and Methods. The data of all patients with metastatic breast cancer receiving vinorelbine with or without trastuzumab during a six year period were reviewed. Patients received vinorelbine intravenous 25–30 mg/m² or 60–80 mg/m² orally in days 1 and 8 of a 21 day cycle. Results. Eighty-seven women were included. Sixty-two patients received vinorelbine alone and 25 patients received vinorelbine in combination with trastuzumab. In 67 patients this was the first line treatment for metastatic disease and in 20 patients it was 2nd or later line of treatment. The median TTP was six months (range: 1–45). The median overall survival was 11.5 months (range: 1–83). Seventy patients were evaluable for response. In patients receiving first line treatment 44.4% had a response while in the second and subsequent lines setting 12.5% of patients responded (P = 0.001). Objective response was obtained in 63.6% of patients receiving concomitant trastuzumab and in 25% of patients receiving vinorelbine alone (P = 0.0002). Conclusion. This study confirms a high disease control rate. Response rate and TTP were superior in first line treatment compared to subsequent lines.

Clinical outcomes and cardiac safety of continuous antiHer2 therapy in c-erbB2-positive metastatic breast cancer patients

BACKGROUND

To explore clinical outcomes and cardiac safety of continuous antiHer2 therapy.

PATIENTS AND METHODS

This retrospective study evaluates overall survival (OS), time to treatment failure (TTF), and cardiac safety of 80 consecutive Her2-positive metastatic breast cancer (MBC) patients that received ≥ 12 months of therapy with trastuzumab, followed by lapatinib-based or trastuzumab-based therapy.

RESULTS

All patients received trastuzumab as first antiHer2 therapy; 54% received lapatinib in the second or subsequent line. Median OS was 34 months (12-120 months). Median OS was 48 months in the subgroup of 43 patients who received lapatinib and 26 months in the 37 patients who did not. Median TTF was shorter for lapatinib. There were three cardiac events and trastuzumab-based chemotherapy (CT) was interrupted in one patient because left ventricular ejection fraction (LVEF) decreased to ≤ 40%.

CONCLUSION

Continuous antiHer2 therapy provides good clinical outcomes, especially in those patients who received lapatinib. Cardiac dysfunction was a rare event, reversible, associated to trastuzumab and not related to treatment duration.

Randomized phase II study comparing efficacy and safety of combination-therapy trastuzumab and docetaxel vs. sequential therapy of trastuzumab followed by docetaxel alone at progression as first-line chemotherapy in patients with HER2+ metastatic breast cancer: HERTAX trial

BACKGROUND

Because chemotherapy for metastatic breast cancer (MBC) is associated with relevant toxicity, sequential monotherapy trastuzumab followed by cytotoxic therapy at disease progression might be an attractive approach.

METHODS

In a multicenter phase II trial, 101 patients with overexpression of human epidermal growth factor receptor 2 (HER2(+)) MBC were randomized between combination-therapy trastuzumab (Herceptin) plus docetaxel (H+D) and sequential therapy of single-agent trastuzumab followed at disease progression by docetaxel alone (H→D) as first-line chemotherapy for metastatic disease. The primary endpoint was progression-free survival (PFS) after completed sequential or combination therapy.

RESULTS

For the H+D group the median PFS was 9.4 vs. 9.9 months for the H→D group and 1-year PFS rates were 44% vs. 35%, respectively. However the overall response rates (ORRs) were 79% vs. 53%, respectively (P = .016), and overall survival was 30.5 vs. 19.7 months, respectively (P = .11). In the H→D group, response rates to monotherapy trastuzumab and subsequent docetaxel were 34% and 39%, respectively, with a median PFS during single-agent trastuzumab of 3.9 months. The incidence and severity of neuropathy were significantly higher in the H+D group. Retrospective analysis of trastuzumab treatment beyond progression (applied in 46% of patients in the H+D group and 37% in the H→D group) showed a correlation with longer overall survival in both treatment arms (36.0 vs. 18.0 months and 30.3 vs. 18.6 months, respectively).

CONCLUSION

First-line treatment in patients with MBC with H→D resulted in a similar PFS compared with H+D, but the response rate was lower and the overall survival nonsignificantly shorter.

Trastuzumab and lapatinib beyond trastuzumab progression for metastatic breast cancer: strategies and pitfalls

The discovery of HER2 gene amplification and protein overexpression in approximately 15-20% of breast cancers and access to the tailored humanized antibody, trastuzumab (Herceptin), have heralded a new era in breast cancer therapy. Trastuzumab combined with chemotherapy has caused marked tumor responses and increased overall survival in patients with metastatic breast cancer, and has also increased survival in the adjuvant setting after radical surgery. However, due to many causes, trastuzumab resistance usually occurs during treatment. In this event, possible options include the replacement of trastuzumab with lapatinib, the continuation of trastuzumab after disease progression with changed chemotherapy and the suspension of the use of targeted agents. New-generation tyrosine kinase inhibitors, which have a broader target, are now considered the key to treatment for breast cancer.

MUC1* is a determinant of trastuzumab (Herceptin) resistance in breast cancer cells

In the United States, 211,000 women are diagnosed each year with breast cancer. Of the 42,000 breast cancer patients who overexpress the HER2 growth factor receptor, <35% are responsive to treatment with the HER2-disabling antibody, called trastuzumab (Herceptin). Despite those statistics, women diagnosed with breast cancer are now tested to determine how much of this important growth factor receptor is present in their tumor because patients whose treatment includes trastuzumab are three-times more likely to survive for at least 5 years and are two-times more likely to survive without a cancer recurrence. Unfortunately, even among the group whose cancers originally respond to trastuzumab, 25% of the metastatic breast cancer patients acquire resistance to trastuzumab within the first year of treatment. Follow-on "salvage" therapies have prolonged life for this group but have not been curative. Thus, it is critically important to understand the mechanisms of trastuzumab resistance and develop therapies that reverse or prevent it. Here, we report that molecular analysis of a cancer cell line that was induced to acquire trastuzumab resistance showed a dramatic increase in the amount of the cleaved form of the MUC1 protein, called MUC1*. We recently reported that MUC1* functions as a growth factor receptor on cancer cells and on embryonic stem cells. Here, we show that treating trastuzumab-resistant cancer cells with a combination of MUC1* antagonists and trastuzumab, reverses the drug resistance. Further, HER2-positive cancer cells that are intrinsically resistant to trastuzumab became trastuzumab-sensitive when treated with MUC1* antagonists and trastuzumab. Additionally, we found that tumor cells that had acquired Herceptin resistance had also acquired resistance to standard chemotherapy agents like Taxol, Doxorubicin, and Cyclophosphamide. Acquired resistance to these standard chemotherapy drugs was also reversed by combined treatment with the original drug plus a MUC1* inhibitor.