A combined analysis of two pivotal randomized trials of a single dose of pegfilgrastim per chemotherapy cycle and daily Filgrastim in patients with stage II-IV breast cancer.

This combined, retrospective analysis compared once-per-chemotherapy-cycle pegfilgrastim with daily Filgrastim in breast cancer patients undergoing myelosuppressive chemotherapy enrolled in two similarly designed, randomized, double-blind, pivotal trials. On day 2 of each chemotherapy cycle, a single subcutaneous (SC) injection of pegfilgrastim [either 6 mg (n=77) or 100 microg/kg (n=149)] was administered, or daily Filgrastim SC injections (5 microg/kg/day; n=222) were initiated and continued until either absolute neutrophil count (ANC) > or =10 x 10(9)/l after the expected nadir or for up to 14 days, whichever occurred first. Individually, each of these trials demonstrated that a single pegfilgrastim injection per cycle is as effective at reducing the duration of severe neutropenia as daily injections of Filgrastim. Clinical efficacy data from the two trials were combined for analysis (n=448). The risk of febrile neutropenia (FN; absolute neutrophil count or =38.2 degrees C) was significantly lower [11% vs 19%, respectively; relative risk = 0.56 (95% confidence interval: 0.35, 0.89)] in patients receiving pegfilgrastim than for those receiving Filgrastim. Trends towards lower risks of hospitalization and intravenous anti-infective use were also observed. These observations were consistent irrespective of risk factors, including age, disease stage, performance status and prior treatment. Pegfilgrastim may offer patients more effective protection against neutropenic complications of chemotherapy with fewer injections and less disruption to their lives.Clinical TrialJournal ArticleMulticenter StudyRandomized Controlled TrialSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Determination of oestrogen-receptor status and ERBB2 status of breast carcinoma: a gene-expression profiling study.

BACKGROUND: Gene expression microarrays are being used to develop new prognostic and predictive tests for breast cancer, and might be used at the same time to confirm oestrogen-receptor status and ERBB2 status. Our goal was to establish a new method to assign oestrogen receptor and ERBB2-receptor status to breast carcinoma based on mRNA expression measured using Affymetrix U133A gene-expression profiling. METHODS: We used gene expression data of 495 breast cancer samples to assess the correlation between oestrogen receptor (ESR1) and ERBB2 mRNA and clinical status of these genes (as established by immunohistochemical [IHC] or fluorescence in-situ hybridisation [FISH], or both). Data from 195 fine-needle aspiration (FNA) samples were used to define mRNA cutoff values that assign receptor status. We assessed the accuracy of these cutoffs in two independent datasets: 123 FNA samples and 177 tissue samples (ie, resected or core-needle biopsied tissues). Profiling was done at two institutions by use of the same platform (Affymetrix U133A GeneChip). All data were uniformly normalised with dCHIP software. FINDINGS: ESR1 and ERBB2 mRNA levels correlated closely with routine measurements for receptor status in all three datasets. Spearman's correlation coefficients ranged from 0.62 to 0.77. An ESR1 mRNA cutoff value of 500 identified oestrogen-receptor-positive status with an overall accuracy of 90% (training set), 88% (first validation set), and 96% (second validation set). An ERBB2 mRNA threshold of 1150 identified ERBB2-positive status with the overall accuracy of 93% (training set), 89% (first validation set), and 90% (second validation set). Reproducibility of mRNA measurements in 34 replicate experiments was high (correlation coefficient 0.975 for ESR1, 0.984 for ERBB2). INTERPRETATION: Amounts of ESR1 and ERBB2 mRNA as measured by the Affymetrix GeneChip reliably and reproducibly establish oestrogen-receptor status and ERBB2 status, respectively.Journal ArticleResearch Support, N.I.H. ExtramuralResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Development of acquired resistance to lapatinib may sensitise HER2-positive breast cancer cells to apoptosis induction by obatoclax and TRAIL

Abstract Background Lapatinib has clinical efficacy in the treatment of trastuzumab-refractory HER2-positive breast cancer. However, a significant proportion of patients develop progressive disease due to acquired resistance to the drug. Induction of apoptotic cell death is a key mechanism of action of lapatinib in HER2-positive breast cancer cells. Methods We examined alterations in regulation of the intrinsic and extrinsic apoptosis pathways in cell line models of acquired lapatinib resistance both in vitro and in patient samples from the NCT01485926 clinical trial, and investigated potential strategies to exploit alterations in apoptosis signalling to overcome lapatinib resistance in HER2-positive breast cancer. Results In this study, we examined two cell lines models of acquired lapatinib resistance (SKBR3-L and HCC1954-L) and showed that lapatinib does not induce apoptosis in these cells. We identified alterations in members of the BCL-2 family of proteins, in particular MCL-1 and BAX, which may play a role in resistance to lapatinib. We tested the therapeutic inhibitor obatoclax, which targets MCL-1. Both SKBR3-L and HCC1954-L cells showed greater sensitivity to obatoclax-induced apoptosis than parental cells. Interestingly, we also found that the development of acquired resistance to lapatinib resulted in acquired sensitivity to TRAIL in SKBR3-L cells. Sensitivity to TRAIL in the SKBR3-L cells was associated with reduced phosphorylation of AKT, increased expression of FOXO3a and decreased expression of c-FLIP. In SKBR3-L cells, TRAIL treatment caused activation of caspase 8, caspase 9 and caspase 3/7. In a second resistant model, HCC1954-L cells, p-AKT levels were not decreased and these cells did not show enhanced sensitivity to TRAIL. Furthermore, combining obatoclax with TRAIL improved response in SKBR3-L cells but not in HCC1954-L cells. Conclusions Our findings highlight the possibility of targeting altered apoptotic signalling to overcome acquired lapatinib resistance, and identify potential novel treatment strategies, with potential biomarkers, for HER2-positive breast cancer that is resistant to HER2 targeted therapies

Development of acquired resistance to lapatinib may sensitise HER2-positive breast cancer cells to apoptosis induction by obatoclax and TRAIL.

BackgroundLapatinib has clinical efficacy in the treatment of trastuzumab-refractory HER2-positive breast cancer. However, a significant proportion of patients develop progressive disease due to acquired resistance to the drug. Induction of apoptotic cell death is a key mechanism of action of lapatinib in HER2-positive breast cancer cells.MethodsWe examined alterations in regulation of the intrinsic and extrinsic apoptosis pathways in cell line models of acquired lapatinib resistance both in vitro and in patient samples from the NCT01485926 clinical trial, and investigated potential strategies to exploit alterations in apoptosis signalling to overcome lapatinib resistance in HER2-positive breast cancer.ResultsIn this study, we examined two cell lines models of acquired lapatinib resistance (SKBR3-L and HCC1954-L) and showed that lapatinib does not induce apoptosis in these cells. We identified alterations in members of the BCL-2 family of proteins, in particular MCL-1 and BAX, which may play a role in resistance to lapatinib. We tested the therapeutic inhibitor obatoclax, which targets MCL-1. Both SKBR3-L and HCC1954-L cells showed greater sensitivity to obatoclax-induced apoptosis than parental cells. Interestingly, we also found that the development of acquired resistance to lapatinib resulted in acquired sensitivity to TRAIL in SKBR3-L cells. Sensitivity to TRAIL in the SKBR3-L cells was associated with reduced phosphorylation of AKT, increased expression of FOXO3a and decreased expression of c-FLIP. In SKBR3-L cells, TRAIL treatment caused activation of caspase 8, caspase 9 and caspase 3/7. In a second resistant model, HCC1954-L cells, p-AKT levels were not decreased and these cells did not show enhanced sensitivity to TRAIL. Furthermore, combining obatoclax with TRAIL improved response in SKBR3-L cells but not in HCC1954-L cells.ConclusionsOur findings highlight the possibility of targeting altered apoptotic signalling to overcome acquired lapatinib resistance, and identify potential novel treatment strategies, with potential biomarkers, for HER2-positive breast cancer that is resistant to HER2 targeted therapies