Georg Pfeiler

Adjuvant denosumab in breast cancer (ABCSG-18): a multicentre, randomised, double-blind, placebo-controlled trial

BACKGROUND Adjuvant endocrine therapy compromises bone health in patients with breast cancer, causing osteopenia, osteoporosis, and fractures. Antiresorptive treatments such as bisphosphonates prevent and counteract these side-effects. In this trial, we aimed to investigate the effects of the anti-RANK ligand antibody denosumab in postmenopausal, aromatase inhibitor-treated patients with early-stage hormone receptor-positive breast cancer. METHODS In this prospective, double-blind, placebo-controlled, phase 3 trial, postmenopausal patients with early hormone receptor-positive breast cancer receiving treatment with aromatase inhibitors were randomly assigned in a 1:1 ratio to receive either denosumab 60 mg or placebo administered subcutaneously every 6 months in 58 trial centres in Austria and Sweden. Patients were assigned by an interactive voice response system. The randomisation schedule used a randomly permuted block design with block sizes 2 and 4, stratified by type of hospital regarding Hologic device for DXA scans, previous aromatase inhibitor use, and baseline bone mineral density. Patients, treating physicians, investigators, data managers, and all study personnel were masked to treatment allocation. The primary endpoint was time from randomisation to first clinical fracture, analysed by intention to treat. As an additional sensitivity analysis, we also analysed the primary endpoint on the per-protocol population. Patients were treated until the prespecified number of 247 first clinical fractures was reached. This trial is ongoing (patients are in follow-up) and is registered with the European Clinical Trials Database, number 2005-005275-15, and with ClinicalTrials.gov, number NCT00556374. FINDINGS Between Dec 18, 2006, and July 22, 2013, 3425 eligible patients were enrolled into the trial, of whom 3420 were randomly assigned to receive denosumab 60 mg (n=1711) or placebo (n=1709) subcutaneously every 6 months. Compared with the placebo group, patients in the denosumab group had a significantly delayed time to first clinical fracture (hazard ratio [HR] 0·50 [95% CI 0·39-0·65], p<0·0001). The overall lower number of fractures in the denosumab group (92) than in the placebo group (176) was similar in all patient subgroups, including in patients with a bone mineral density T-score of -1 or higher at baseline (n=1872, HR 0·44 [95% CI 0·31-0·64], p<0·0001) and in those with a bone mineral density T-score of less than -1 already at baseline (n=1548, HR 0·57 [95% CI 0·40-0·82], p=0·002). The patient incidence of adverse events in the safety analysis set (all patients who received at least one dose of study drug) did not differ between the denosumab group (1366 events, 80%) and the placebo group (1334 events, 79%), nor did the numbers of serious adverse events (521 vs 511 [30% in each group]). The main adverse events were arthralgia and other aromatase-inhibitor related symptoms; no additional toxicity from the study drug was reported. Despite proactive adjudication of every potential osteonecrosis of the jaw by an international expert panel, no cases of osteonecrosis of the jaw were reported. 93 patients (3% of the full analysis set) died during the study, of which one death (in the denosumab group) was thought to be related to the study drug. INTERPRETATION Adjuvant denosumab 60 mg twice per year reduces the risk of clinical fractures in postmenopausal women with breast cancer receiving aromatase inhibitors, and can be administered without added toxicity. Since a main side-effect of adjuvant breast cancer treatment can be substantially reduced by the addition of denosumab, this treatment should be considered for clinical practice. FUNDING Amgen.

Detection of EpCAM positive and negative circulating tumor cells in metastatic breast cancer patients

Abstract Background. Immunomagnetic EpCAM based methods are used to enrich circulating tumor cells (CTCs) in metastatic breast cancer (mBC) patients. EpCAM negative CTCs may be missed. We addressed the question of the reliability of an EpCAM dependent assay to enrich CTCs. Methods. To elucidate this issue, our study has been designed to assess two different CTC enrichment technologies (i) in EpCAM positive (+) and EpCAM negative cell lines and (ii) in mBC patients in dependency on their respective EpCAM expression. These two technologies encompass one anti-EpCAM immunomagnetic enrichment technology, MACS HEA MicroBeads® (MACS), and one EpCAM independent density centrifugation method, OncoQuick® plus (OQ+). Furthermore, the coherence between EpCAM expression in the primary tumor tissue of mBC patients and the CTC detection rates in the corresponding patients is analyzed. Results. (i) MACS recovered significantly more EpCAM (+) than EpCAM (−) tumor cells (p < 0.001) in spiked blood samples. With OQ+ no significantly different recovery rates between EpCAM (+) and EpCAM (−) tumor cells (p = 0.796) were detected. (ii) In mBC patients MACS yielded a significantly higher (p = 0.024) detection rate of EpCAM (+) CTCs. No statistically significant difference (p = 0.070) was found concerning the EpCAM status-based detection rate of CTCs by OQ+. (iii) CTC detection rates are independent of the primary tumors’ EpCAM expression. Conclusions. EpCAM (−) CTCs can not be detected by immunomagnetic EpCAM dependent enrichment methods. EpCAM independent enrichment technologies seem to be superior to detect the entire CTC population. Evaluation of CTCs as prognostic marker should compromise EpCAM (+) and (−) subpopulations.

RANKL/RANK control Brca1 mutation-driven mammary tumors

Breast cancer is the most common female cancer, affecting approximately one in eight women during their life-time. Besides environmental triggers and hormones, inherited mutations in the breast cancer 1 (BRCA1) or BRCA2 genes markedly increase the risk for the development of breast cancer. Here, using two different mouse models, we show that genetic inactivation of the key osteoclast differentiation factor RANK in the mammary epithelium markedly delayed onset, reduced incidence, and attenuated progression of Brca1;p53 mutation-driven mammary cancer. Long-term pharmacological inhibition of the RANK ligand RANKL in mice abolished the occurrence of Brca1 mutation-driven pre-neoplastic lesions. Mechanistically, genetic inactivation of Rank or RANKL/RANK blockade impaired proliferation and expansion of both murine Brca1;p53 mutant mammary stem cells and mammary progenitors from human BRCA1 mutation carriers. In addition, genome variations within the RANK locus were significantly associated with risk of developing breast cancer in women with BRCA1 mutations. Thus, RANKL/RANK control progenitor cell expansion and tumorigenesis in inherited breast cancer. These results present a viable strategy for the possible prevention of breast cancer in BRCA1 mutant patients.

Circulating tumor cells in metastatic colorectal cancer: Efficacy and feasibility of different enrichment methods

Comprehensive in vitro and in vivo studies comparing EpCAM-based methods with other cytometric CTC enrichment technologies in metastatic colorectal cancer (mCRC) patients are lacking. We compare four manual cytometric methods to detect CTCs in vitro and in mCRC patients. The EpCAM-based technology, MACS HEA MicroBeads((R)), showed a significant better tumor cell recovery rate compared to other cytometric methods (p-value<0.0001). CTCs of 38 mCRC patients were enriched with MACS HEA MicroBeads(R). Progression-free survival did significantly differ between mCRC patients without detectable and with >or= 1 CTCs (p=0.007). CTC enrichment with EpCAM coupled antibodies is superior to other cytometric methods and is a feasible method for CTC detection in mCRC patients.

Genetic variation in insulin-like growth factor signaling genes and breast cancer risk among BRCA1 and BRCA2 carriers.

IntroductionWomen who carry mutations in BRCA1 and BRCA2 have a substantially increased risk of developing breast cancer as compared with the general population. However, risk estimates range from 20 to 80%, suggesting the presence of genetic and/or environmental risk modifiers. Based on extensive in vivo and in vitro studies, one important pathway for breast cancer pathogenesis may be the insulin-like growth factor (IGF) signaling pathway, which regulates both cellular proliferation and apoptosis. BRCA1 has been shown to directly interact with IGF signaling such that variants in this pathway may modify risk of cancer in women carrying BRCA mutations. In this study, we investigate the association of variants in genes involved in IGF signaling and risk of breast cancer in women who carry deleterious BRCA1 and BRCA2 mutations.MethodsA cohort of 1,665 adult, female mutation carriers, including 1,122 BRCA1 carriers (433 cases) and 543 BRCA2 carriers (238 cases) were genotyped for SNPs in IGF1, IGF1 receptor (IGF1R), IGF1 binding protein (IGFBP1, IGFBP2, IGFBP5), and IGF receptor substrate 1 (IRS1). Cox proportional hazards regression was used to model time from birth to diagnosis of breast cancer for BRCA1 and BRCA2 carriers separately. For linkage disequilibrium (LD) blocks with multiple SNPs, an additive genetic model was assumed; and for single SNP analyses, no additivity assumptions were made.ResultsAmong BRCA1 carriers, significant associations were found between risk of breast cancer and LD blocks in IGF1R (global P = 0.011 for LD block 2 and global P = 0.012 for LD block 11). Among BRCA2 carriers, an LD block in IGFBP2 (global P = 0.0145) was found to be associated with the time to breast cancer diagnosis. No significant LD block associations were found for the other investigated genes among BRCA1 and BRCA2 carriers.ConclusionsThis is the first study to investigate the role of genetic variation in IGF signaling and breast cancer risk in women carrying deleterious mutations in BRCA1 and BRCA2. We identified significant associations in variants in IGF1R and IRS1 in BRCA1 carriers and in IGFBP2 in BRCA2 carriers. Although there is known to be interaction of BRCA1 and IGF signaling, further replication and identification of causal mechanisms are needed to better understand these associations.

Adiponectin differentially affects gene expression in human mammary epithelial and breast cancer cells

Serum levels of adiponectin are inversely associated with breast cancer risk. In this study, its effect on growth and gene expression of MCF-7 breast cancer cells and MCF-10A human mammary epithelial cells was compared. The antiproliferative effect of adiponectin on MCF-10A cells was more pronounced and was accompanied by elevated transcript levels of caspase 1, ERβ2, ERβ5, TR2 and USP2. Our data suggest that upregulation of genes with known growth inhibitory or apoptotic functions in mammary epithelial cells might contribute to the protective action of this adipocytokine.

Vaginal estriol to overcome side-effects of aromatase inhibitors in breast cancer patients

Objective Aromatase inhibitors are essential as endocrine treatment for hormone receptor-positive postmenopausal breast cancer patients. Menopausal symptoms are often aggravated during endocrine treatment. We investigated whether vaginal estriol is a safe therapeutic option to overcome the urogenital side-effects of aromatase inhibitors. Serum hormone levels were used as the surrogate parameter for safety. Methods Fasting serum hormone levels of ten postmenopausal breast cancer patients receiving aromatase inhibitors were prospectively measured by electro-chemiluminescence immunoassays and gas chromatography/mass spectrometry before and 2 weeks after daily application of 0.5 mg vaginal estriol (Ovestin® ovula), respectively. Results Two weeks of daily vaginal estriol treatment did not change serum estradiol or estriol levels. However, significant decreases in levels of serum follicle stimulating hormone (p = 0.01) and luteinizing hormone (p = 0.02) were observed. Five out of six breast cancer patients noticed an improvement in vaginal dryness and/or dyspareunia. Conclusions The significant decline in gonadotropin levels, indicating systemic effects, has to be kept in mind when offering vaginal estriol to breast cancer patients receiving an aromatase inhibitor.

Modification of Ovarian Cancer Risk by BRCA1/2-Interacting Genes in a Multicenter Cohort of BRCA1/2 Mutation Carriers

Inherited BRCA1/2 mutations confer elevated ovarian cancer risk. Knowledge of factors that can improve ovarian cancer risk assessment in BRCA1/2 mutation carriers is important because no effective early detection for ovarian cancers exists. A cohort of 1,575 BRCA1 and 856 BRCA2 mutation carriers was used to evaluate haplotypes at ATM, BARD1, BRIP1, CTIP, MRE11, NBS1, RAD50, RAD51, and TOPBP1 in ovarian cancer risk. In BRCA1 carriers, no associations were observed with ATM, BARD1, CTIP, RAD50, RAD51, or TOPBP1. At BRIP1, an association was observed for one haplotype with a multiple testing corrected P (P(corr)) = 0.012, although no individual haplotype was significant. At MRE11, statistically significant associations were observed for one haplotype (P(corr) = 0.007). At NBS1, we observed a P(corr) = 0.024 for haplotypes. In BRCA2 carriers, no associations were observed with CTIP, NBS1, RAD50, or TOPBP1. Rare haplotypes at ATM (P(corr) = 0.044) and BARD1 (P(corr) = 0.012) were associated with ovarian cancer risk. At BRIP1, two common haplotypes were significantly associated with ovarian cancer risk (P(corr) = 0.011). At MRE11, we observed a significant haplotype association (P(corr) = 0.012), and at RAD51, one common haplotype was significantly associated with ovarian cancer risk (P(corr) = 0.026). Variants in genes that interact biologically withBRCA1 and/or BRCA2 may be associated with modified ovarian cancer risk in women who carry BRCA1/2 mutations.

The predictive impact of body mass index on the efficacy of extended adjuvant endocrine treatment with anastrozole in postmenopausal patients with breast cancer: an analysis of the randomised ABCSG-6a trial.

Background:We investigated whether body mass index (BMI) can be used as a predictive parameter indicating patients who benefit from extended aromatase inhibitor (AI) treatment.Methods:The ABCSG-6a trial re-randomised event-free postmenopausal hormone receptor-positive patients from the ABCSG-6 trial to receive either 3 additional years of endocrine therapy using anastrozole vs nil. In this retrospective analysis, we investigated the prognostic and predictive impact of BMI on disease outcome and safety.Results:In all, 634 patients (177 normal weight, 307 overweight, and 150 obese) patients were included in this analysis. Normal weight patients with additional 3 years of anastrozole halved their risk of disease recurrence (disease-free survival (DFS) HR 0.48; P=0.02) and death (HR 0.45; P=0.06) and had only a fifth of the risk of distant metastases (HR 0.22; P=0.05) compared with normal weight patients without any further treatment. In contrast, overweight+obese patients derived no benefit from additional 3 years of anastrozole (DFS HR 0.93; P=0.68; distant recurrence-free survival HR 0.91; P=0.78; and OS HR 0.9; P=0.68). The possible predictive impact of BMI on extended endocrine treatment could be strengthened by a Cox regression interaction model between BMI and treatment (P=0.07).Conclusion:Body mass index may be used to predict outcome benefit of extended AI treatment in patients with receptor-positive breast cancer.

Impact of body mass index on estradiol depletion by aromatase inhibitors in postmenopausal women with early breast cancer

Background:Body mass index (BMI) has an impact on survival outcome in patients treated with aromatase inhibitors (AIs). Obesity is associated with an increased body aromatisation and may be a cause of insufficient estradiol depletion.Methods:Sixty-eight postmenopausal oestrogen receptor-positive patients with early breast cancer were prospectively included in this study. Follicle stimulating hormone (FSH), luteinizing hormone (LH) and estradiol were analysed immediately in the clinical routine lab and in a dedicated central lab before (T1) and 3 months after start with aromatase inhibitors (T2).Results:A total of 40 patients were normal or overweight (non-obese: BMI 18.5–29.9 kg m−2) and 28 were obese (BMI⩾30 kg m−2). Aromatase inhibitors significantly suppressed estradiol serum levels (T1: 19.5 pg ml−1, T2: 10.5 pg ml−1, P<0.01) and increased FSH serum levels (T1: 70.2 mIU ml−1, T2: 75.7 mIU ml−1, P<0.05). However, after 3 months of AI treatment, estradiol levels of obese patients were nonsignificantly higher compared with non-obese patients (12.5 pg ml−1 vs 9.0 pg ml−1, P=0.1). This difference was reflected by significantly lower FSH serum levels in obese compared with non-obese patients (65.5 mIU ml−1 vs 84.6 mIU ml−1, P<0.01). The significant effects of BMI on FSH serum levels could be detected both in the routine as well as in the dedicated central lab.Conclusion:Aromatase inhibitors are less efficient at suppressing estradiol serum levels in obese when compared with non-obese women.