Taxanes Plus Trastuzumab Compared To Oral Vinorelbine Plus Trastuzumab in HER2-Overexpressing Metastatic Breast Cancer

BACKGROUND

This retrospective analysis was planned as a direct comparison of taxanes plus trastuzumab to the less toxic combination of oral vinorelbine (OV) plus trastuzumab as a first-line therapy for metastatic HER2-positive breast cancer.

PATIENTS AND METHODS

Patients (n = 76) receiving either taxanes (group A) or OV (group B) in combination with trastuzumab were identified from a breast cancer database. Progression-free survival (PFS) was defined as the primary study endpoint; secondary endpoints were overall survival (OS), response rate (RR), incidence of brain metastases, and brain metastases-free survival (BMFS).

RESULTS

36 patients received taxanes and 40 patients OV in combination with trastuzumab. At a median follow-up of 47.5 months, median PFS was 7 months (group A) and 9 months in group B (log-rank; non-significant), respective numbers for OS were 49 and 59 months (p = 0.033). The incidence of brain metastases did not differ significantly between the 2 treatment groups, whereas BMFS was significantly longer in patients receiving OV.

CONCLUSIONS

OV plus trastuzumab yielded similar results in terms of PFS and RR and was superior in terms of OS and BMFS. These results add to the growing body of evidence that vinorelbine is a viable alternative to taxanes in HER2-positive metastatic breast cancer.

Hypertension as a predictive marker for bevacizumab in metastatic breast cancer: results from a retrospective matched-pair analysis

BACKGROUND

Several phase-III studies have shown improvements in terms of progression-free survival (PFS) with bevacizumab when added to chemotherapy in advanced breast cancer. However, the extent of improvement varied and none of the trials showed benefit in terms of overall survival (OS).

PATIENTS AND METHODS

All patients with metastatic breast cancer treated with bevacizumab at our Institution between 2005 and 2011 were retrospectively analyzed. A control group was matched according to the following variables: receptor status, treatment line, type of chemotherapy, presence of visceral disease and age.

RESULTS

All 212 patients were evaluable for toxicity, and 198 for response; 430 controls allowed a complete matching for 85 bevacizumab-treated patients. The addition of bevacizumab to chemotherapy significantly prolonged PFS (9.3 vs. 7.6 months, hazard ratio [HR]=0.70, 95% confidence interval [CI]=0.51-0.97, p=0.031) and OS (28.9 vs. 22.6 months, HR=0.67, 95% CI=0.45-0.99, p=0.043). Clinical benefit rate (overall response rate + stable disease for at least six months) was significantly better in the bevacizumab group (75% vs. 59%, p=0.002), while ORR did not differ significantly (48% vs. 35%, p=0.21). Patients developing hypertension during treatment had a more favourable outcome (PFS 13.7 vs. 6.6 months, HR=0.34, 95% CI=0.23-0.49 p<0.001; 2-year OS 78% vs. 30%, HR=0.20, 95% CI=0.12-0.35, p<0.001).

CONCLUSION

Bevacizumab in addition to chemotherapy prolonged PFS and OS in a non-selected, partly intensively pre-treated breast cancer population. Hypertension induced by bevacizumab predicted therapy efficacy.

Low HER2-expression to predict impaired activity of endocrine therapy in patients with estrogen-receptor (ER) positive metastatic breast cancer (MBC)

573

Background: ER cross-activation by growth-factor signalling causes resistance to endocrine therapy (ET) in patients (pts) with Her2-positive MBC. Moreover, low levels of Her2-expression (Her2 1+; Her2 2+ without gene amplification), may result in reduced efficacy of ET in early breast cancer pts. In a recently published study, these tumours had a less favourable outcome as compared to tumours with a Her2-score of 0. Here, we investigated if low levels of Her2-expression could predict for shorter progression-free survival (PFS) in MBC pts on ET. Methods: PFS on first-line ET was chosen as primary endpoint and estimated with the Kaplan-Meier method. To test for differences between PFS curves, the log-rank test was used. Association of the following variables with PFS was investigated: low Her2-expression, grading, level of ER-expression, progesterone-receptor status, Ki67 (cut-off ≤20%), prior adjuvant ET, and presence of visceral metastases. For an estimated superiority of 40% in terms of PFS in favour of the Her2-negative group, a sample of 130 pts in two groups was needed in order to rule out the null-hypothesis with a 80% power and a two-sided α of 0.025. Results: A total number of 320 ER-positive MBC pts were identified from a breast cancer database; 170 pts were available for this analysis. Median PFS on first-line ET was 11 months (m) (8.56-13.44), corresponding numbers for second-line were 6 m (4.65-7.36), and third-line 4 m (1.52-6.48), respectively; median OS from diagnosis of MBC was 58 m (48.15-67.86). None of the variables investigated were significantly associated with first-line PFS. Second-line PFS, however, was significantly shorter in pts with grade 3 tumours and prior adjuvant ET; a trend towards shorter PFS was observed in high proliferating tumours. Conclusions: In this chart review, low levels of Her2 expression did not predict for shorter PFS in pts receiving ET; PFS in different treatment lines was well in line with data from clinical trials. High tumour grading and prior adjuvant ET were associated with accelerated onset of resistance, rendering those patients candidates for early combination of ET with targeted treatment approaches.

Abstract P5-20-11: Bevacizumab in metastatic breast cancer: a retrospective matched-pair analysis

Background: In November 2011 the FDA withdrew accelerated approval of the breast cancer indication for bevacizumab, because “the drug has not been shown to be safe and effective for this use” (FDA Commissioner M. A. Hamburg, MD). The objective of this analysis was to evaluate efficacy and safety of bevacizumab in non-selected patients with stage IV breast cancer.

Patients and methods: All patients with metastatic breast cancer treated with bevacizumab in combination with chemotherapy in our institution between 2005 and 2011 were retrospectively analysed. At least 1 cycle of bevacizumab was required for safety analysis, 3 applications for efficacy evaluation. A control group was matched according to the following criteria: receptor status, line of treatment, chemotherapy backbone, visceral or non-visceral disease and age.

Results: A total of 213 patients fulfilled the inclusion criteria. All of them were evaluable for toxicity, 199 for response. 503 potential controls allowed a complete matching for 103 patients. Fifty-eight percent of patients received first-line, 15% second-line and 27% of patients beyond second-line treatment. Visceral metastases were present in 69% of patients in both groups. The most common chemotherapy backbones were paclitaxel, capecitabine and docetaxel with 44%, 32% and 19%, respectively.