High concordance of protein (by IHC), gene (by FISH; HER2 only), and microarray readout (by TargetPrint) of ER, PgR, and HER2: results from the EORTC 10041/BIG 03-04 MINDACT trial

BACKGROUND

To investigate the correlation of TargetPrint with local and central immunohistochemistry/fluorescence in situ hybridization assessment of estrogen (ER), progesterone (PgR), and human epidermal growth factor receptor 2 (HER2) in the first 800 patients enrolled in the MINDACT trial.

PATIENTS AND METHODS

Data from local (N = 800) and central (N = 626) assessments of receptor status were collected and compared with TargetPrint results.

RESULTS

For ER, the positive agreement (the percentage of central pathology positive assessments that were also TargetPrint/local laboratory positive) for TargetPrint in comparison to centralized assessment was 98% with a negative agreement (the percentage of central pathology negative assessments that were also TargetPrint/local laboratory negative) of 96%. For PgR, the positive agreement was 83% with a negative agreement of 92%. For HER2, the positive agreement was 75% with a negative agreement of 99%. Even though the local assessment showed higher positive agreement for PgR (89%) and higher positive agreement for HER2 (85%), the range of discordant local versus central assessments were as high as 6.7% for ER, 12.9% for PgR, and 4.3% for HER2.

CONCLUSION

TargetPrint and local assessment of ER, PgR, and HER2 show high concordance with central assessment in the first 800 MINDACT patients. However, there are concerns about the higher discordance rates for some local sites. TargetPrint can improve the reliability of hormone receptor and HER2 testing for those centers with a lower rate of concordance with the reference laboratory, with the limitation of a positive agreement of 75% for HER2. TargetPrint consequently has important implications for treatment decisions in clinical practice and is a reliable alternative to local assessment for ER.

CLINICAL TRIALS NUMBER

NCT00433589.

SoMore trial: Early metabolic response assessment of a sorafenib (SOR) and capecitabine (CAP) combination in chemorefractory metastatic colorectal cancer (mCRC)

524

Background: The SOR-CAP combination has shown clinical activity in several phase I-II trials involving metastatic breast cancer and mCRC patients (pts). SoMore aims to substantiate the combination’s effects in mCRC refractory to all medications and the predictive value of early metabolic response (MR) on survival. Methods: SoMore (EUDRACT 2010-023695-91) has 2 coprimary objectives: 1) to demonstrate an overall survival (OS) rate at 6 months (mths) > 30%, and 2) to compare OS between pts with and without MR. CAP was given at 1700 mg/m²/day (D), 2 weeks out of 3. SOR was administered at 600mg/D for the first cycle, then at 800mg/D until progression or unacceptable toxicity. FDGPET-CT was performed at baseline and before the 2nd cycle. MR analysis was centralized and blinded for the investigators. Results: From February to October 2011, 92 eligible pts were prospectively recruited in 6 Belgian centers: M/F: 54%/46%; ECOG PS 0/1: 55%/45%; median age: 61. A median of 5 treatment cycles were given (0-28+). Grade 3-4 toxic reactions were reported in 61.2%, mainly fatigue (18%), hand-foot skin reaction (14%) and diarrhea (11%), but no toxic death. 6.9% of the pts stopped therapy due to toxicity. 6 mths OS was 71% (95% CI: 61%-79%), significantly >30% (p<0.001). 47% of the 79 pts evaluable for metabolic assessment showed homogeneous MR (HMR) of all metastatic lesions, 32% mixed MR and 21% homogeneous non-MR. Median overall OS and PFS of the intent-to-treat population and of pts with and without HMR are shown in the table below. Hazard ratio for HMR was 0.34 (95% CI, 0.21 to 0.56) p-value <0.001 for PFS and 0.59 (95% CI, 0.37 to 0.96) p-value 0.03 for OS. Conclusions: These data suggest robust efficacy for the SOR-CAP combination in heavily pretreated mCRC, associated with high but manageable toxicity. Early MR assessment, by detecting unresponsive lesions within the whole body tumoral load, is able to capture the pts’ likelihood of benefit, opening the path to personalized medicine. Clinical trial information: NCT01290926. [Table: see text]

Preoperative (preop) chemosensitivity testing as predictor of treatment benefit in adjuvant stage III colon cancer (CC): Interim analysis of the PEPITA study

385

Background: Adjuvant chemotherapy (CT) improves stage III CC outcome but is not effective for all patients (pts). PePiTA’s main hypothesis is that absence of metabolic response (MR) of the primary tumor after 1 preop CT course predicts absence of benefit from adjuvant CT (at 3-year DFS). This strategy's aim is to spare pts from useless toxicities, improve healthcare resource allocation, and guide translational research. This interim analysis was performed for safety and feasibility of MR assessment (MRA). Methods: Pts ≥ 18 years, with PS ≤ 1, diagnosed with CC considered for curative resection are eligible, after signed consent. Baseline PET is repeated after 1 CT cycle, followed by surgery. PET quality insurance and MRA are performed centrally and the result is blinded for investigators. Results: From 2010 to 2013, 114 pts—M/F (55%/45%), median age 66 (26-81), ECOG 0/1(92%/8%)—were included in 15 Belgian centers. 11 pts were excluded from analysis: 2 hyperglycemia at baseline PET; 2 withdrew consent; 6 PET-revealed stage IV CC; and 1 second cancer. Preop CT was associated with 5% grade (gr) 3-4 neutropenia, 1% gr 3 diarrhea, 1% gr 3 hypokaliemia, 1% peritonitis and 1% gr 3 thromboembolic events. Colectomies were performed in all pts after a median of 20 days (interquartile interval 18-21): 32 right (31%), 69 left (67%), and 2 procedures not detailed. Pathology showed stages 0 (1%), I (13%), II (34%), III (47%), IV (7%), without lymph node downstaging. Postoperative morbidity is 9% (95%CI 5-16%) and includes fistulas (4%), transient ischemic attack (1%), ileus (2%), and evisceration (1%), but no death. Technical or methodological reasons prevented MRA in 19/103 pts. Median SUVmax was 14.4 (4.9-47.8) at baseline, and 10.9 (0-39.3) on day 14. 2 pts presented with complete MR. For the others, median delta SUVmax was -22% (-60 to +31%). MR was observed in 60% of pts, and was absent in 40%, with equal distribution for stages II and III (p = 1.00). Conclusions: 1 course of CT is feasible before curative surgery for CC, without inducing excessive toxicity, delay or surgical morbidity. MRA indicated metabolic signs of chemoresistance in 40% of the primary tumors. Clinical trial information: NCT00994864.

2 years versus 1 year of adjuvant trastuzumab for HER2-positive breast cancer (HERA): an open-label, randomised controlled trial

BACKGROUND

Trastuzumab has established efficacy against breast cancer with overexpression or amplification of the HER2 oncogene. The standard of care is 1 year of adjuvant trastuzumab, but the optimum duration of treatment is unknown. We compared 2 years of treatment with trastuzumab with 1 year of treatment, and updated the comparison of 1 year of trastuzumab versus observation at a median follow-up of 8 years, for patients enrolled in the HERceptin Adjuvant (HERA) trial.

METHODS

The HERA trial is an international, multicentre, randomised, open-label, phase 3 trial comparing treatment with trastuzumab for 1 and 2 years with observation after standard neoadjuvant chemotherapy, adjuvant chemotherapy, or both in 5102 patients with HER2-positive early breast cancer. The primary endpoint was disease-free survival. The comparison of 2 years versus 1 year of trastuzumab treatment involved a landmark analysis of 3105 patients who were disease-free 12 months after randomisation to one of the trastuzumab groups, and was planned after observing at least 725 disease-free survival events. The updated intention-to-treat comparison of 1 year trastuzumab treatment versus observation alone in 3399 patients at a median follow-up of 8 years (range 0-10) is also reported. This study is registered with ClinicalTrials.gov, number NCT00045032.

FINDINGS

We recorded 367 events of disease-free survival in 1552 patients in the 1 year group and 367 events in 1553 patients in the 2 year group (hazard ratio [HR] 0·99, 95% CI 0·85-1·14, p=0·86). Grade 3-4 adverse events and decreases in left ventricular ejection fraction during treatment were reported more frequently in the 2 year treatment group than in the 1 year group (342 [20·4%] vs 275 [16·3%] grade 3-4 adverse events, and 120 [7·2%] vs 69 [4·1%] decreases in left ventricular ejection fraction, respectively). HRs for a comparison of 1 year of trastuzumab treatment versus observation were 0·76 (95% CI 0·67-0·86, p<0·0001) for disease-free survival and 0·76 (0·65-0·88, p=0·0005) for overall survival, despite crossover of 884 (52%) patients from the observation group to trastuzumab therapy.

INTERPRETATION

2 years of adjuvant trastuzumab is not more effective than is 1 year of treatment for patients with HER2-positive early breast cancer. 1 year of treatment provides a significant disease-free and overall survival benefit compared with observation and remains the standard of care.

FUNDING

F Hoffmann-La Roche (Roche).

Correlation of molecular alterations with efficacy of everolimus in hormone-receptor–positive, HER2-negative advanced breast cancer: Results from BOLERO-2

142

Background: Everolimus (EVE) plus exemestane (EXE) more than doubled progression-free survival (PFS) while maintaining quality of life vs EXE alone in postmenopausal women with hormone receptor–positive (HR+), HER2-negative (HER2–) advanced breast cancer (BOLERO-2 phase III; NCT00863655). PFS benefit was seen in all clinically defined subgroups. We evaluated genetic variations of a broad panel of cancer-related genes and explored their correlations with EVE benefit. Methods: Exon sequence and gene copy number variations were analyzed in 182 cancer-related genes by next-generation sequencing (NGS). Correlations with PFS were evaluated using univariate and multivariate Cox models. Results: NGS data (>250x coverage) were successfully generated from archival tumor specimens from 227 patients (NGS population, 157 in EVE + EXE arm and 70 in EXE arm) whose baseline characteristics and clinical outcome were comparable to the trial population (PFS HR = 0.40 and 0.45, respectively). The treatment benefit of EVE + EXE over EXE was maintained in the subgroups defined by each of the 9 genes with a mutation rate >10% (e.g., PIK3CA, FGFR1, CCND1) or when less frequently mutated genes (e.g., PTEN, AKT1) were included in their respective pathways. Patients with 0 or 1 genetic alteration in PI3K or FGFR pathways or CCND1 had a greater treatment effect from EVE (HR = 0.27, 95% CI 0.18-0.41, adjusted by covariates, in 76% of the NGS population), indicating the value of these pathways for predicting sensitivity to EVE in this setting. Conclusions: This is the first global registration trial in which efficacy-predictive biomarkers were explored by correlating broad genetic variations with clinical efficacy. The preliminary results suggest that a large subgroup of patients (76%), defined by minimal genetic variations in the PI3K or FGFR pathways or CCND1, derives the most benefit from EVE therapy (HR = 0.27 vs 0.40 for the full NGS population). These exploratory results and their implication in understanding the interplay of multiple pathways in tumor cells and testing new hypotheses for targeted combination therapies in HR+/HER2– BC will be further investigated. Clinical trial information: NCT00863655.

Correlation of molecular alterations with efficacy of everolimus in hormone receptor–positive, HER2-negative advanced breast cancer: Results from BOLERO-2

LBA509

Background: Everolimus (EVE) plus exemestane (EXE) more than doubled progression-free survival (PFS) while maintaining quality of life vs EXE alone in postmenopausal women with hormone-receptor positive (HR+), HER2-negative (HER2-) advanced breast cancer (BOLERO-2 phase III; NCT00863655). PFS benefit was seen in all clinically defined subgroups. We evaluated genetic variations of a broad panel of cancer-related genes and explored their correlations with EVE benefit. Methods: Exon sequence and gene copy number variations were analyzed in 182 cancer-related genes by next-generation sequencing (NGS). Correlations with PFS were evaluated using both univariate and multivariate Cox models. Results: NGS data (>250x coverage) were successfully generated from archival tumor specimens from 227 patients (NGS population, 157 and 70 in EVE+EXE and EXE arms, respectively) whose baseline characteristics and clinical outcome were comparable with the trial population (PFS HR = 0.40 and 0.45, respectively). The treatment benefit of EVE+EXE over EXE is maintained in the subgroups defined by each of the nine genes with a mutation rate >10% (eg, PIK3CA, FGFR1, and CCND1), or when less frequently mutated genes (eg, PTEN, AKT1) were included in their respective pathways. Patients with no or only 1 genetic alteration in PI3K or FGFR pathways, or CCND1, had a greater treatment effect from EVE (HR = 0.27, 95% CI 0.18-0.41, adjusted by covariates, in 76% of the NGS population), indicating the value of these pathways for predicting sensitivity/resistance to EVE in this setting. Conclusions: This is the first global registration trial in which efficacy-predictive biomarkers were explored by correlating broad genetic variations with clinical efficacy. It demonstrated the feasibility of applying large-scale NGS and subsequent correlative analysis to such trials. The observations suggest that a large subgroup of patients (76%), defined by minimal genetic variations in the PI3K or FGFR pathways, or CCND1, derives the most benefit from EVE therapy (HR = 0.27 vs 0.40 for the full NGS population). These exploratory results and their implication in understanding the interplay of multiple pathways in tumor cells and testing new hypotheses for targeted combination therapies in HR+/HER2- BC will be further investigated. Clinical trial information: NCT00863655.

Effect of age on breast cancer outcomes in women with human epidermal growth factor receptor 2-positive breast cancer: results from a herceptin adjuvant trial

PURPOSE

Previous research has suggested that young age at diagnosis is an independent risk factor for breast cancer recurrence and death. No prior studies have adequately controlled for human epidermal growth factor receptor 2 (HER2) status or anti-HER2 treatment. We sought to evaluate whether age was a prognostic or predictive factor in the HERA trial.

PATIENTS AND METHODS

We used 2-year median follow-up data and dichotomized age at 40 years to evaluate its prognostic effect on outcomes for women assigned to trastuzumab for 1 year or observation.

RESULTS

Of the 1,703 women randomly assigned to 1 year of trastuzumab and 1,698 to observation, 722 (21%) were age ≤ 40 years at study entry. In separate Cox models, controlling for relevant prognostic and predictive factors, disease-free (DFS) and overall survival (OS) hazard ratios (HRs) were consistent for women age ≤ 40 versus > 40 years, regardless of treatment assignment (observation group: DFS HR age ≤ 40 v > 40 years, 1.18; 95% CI, 0.90 to 1.54; OS HR age ≤ 40 v > 40 years, 1.01; 95% CI, 0.60 to 1.69; trastuzumab group: DFS HR age ≤ 40 v > 40 years, 1.11; 95% CI, 0.81 to 1.51; OS HR age ≤ 40 v > 40 years, 1.18; 95% CI, 0.66 to 2.09). Interaction between age group and treatment effect was not statistically significant (DFS P = .89; OS P = .55).

CONCLUSION

In a retrospective analysis of a large randomized controlled trial of women with early-stage HER2-positive breast cancer, age was not strongly associated with risk of early recurrence or prediction of benefit from trastuzumab therapy. Future research should investigate whether age is a predictor of later recurrence and evaluate the impact of age within groups with other tumor subtypes.

Progression-free survival (PFS) as surrogate endpoint for overall survival (OS) in clinical trials of HER2-targeted agents in HER2-positive metastatic breast cancer (MBC): An individual patient data (IPD) analysis

610

Background: The gold standard endpoint in randomized clinical trials (RCTs) in MBC is OS, which has the disadvantage of requiring extended follow-up and being confounded by subsequent anti-cancer therapies. Although therapeutics have been approved based on PFS, its use as a primary endpoint is controversial. This study, the first IPD meta-analysis of targeted agents in MBC, aimed to collect data from RCTs of HER2-targeted agents in HER2+ MBC, assessing to what extent PFS correlates with, and may be used as, a surrogate for OS. Methods: A search was conducted in April 2011. Eligible RCTs accrued HER2+ MBC patients (pts) in 1992-2008. Collaboration was obtained from industrial partners (Roche, GSK) for industry-led studies. Investigator-assessed PFS was defined as the time from randomization to clinical or radiological progression, or death. A correlation approach was used: at the individual level, to estimate the association between PFS and OS using a bivariate survival model and at the trial level, to estimate the association between treatment effects on PFS and OS. Squared correlation values close to 1.0 would indicate strong surrogacy. Results: The search strategy resulted in 2137 eligible pts in 13 RCTs testing trastuzumab or lapatinib. We collected IPD data from 1963 pts in 9 RCTs. One phase II RCT did not have sufficient follow-up data so that 1839 pts in 8 RCTs were retained (5 evaluating trastuzumab, 3 lapatinib); 6 out of 8 RCTs were first-line. At the individual level, the Spearman rank correlation using Hougaard copula was equal to r=0.66 (95% CI 0.65 to 0.66) corresponding to an r2 of 0.42. At the trial level, the squared correlation between treatment effects on PFS and OS was provided by R2=0.33 (95% CI -0.22 to 0.86) using Hougaard copula and R2=0.53 (95% CI 0.22 to 0.83) using log hazard ratios from Cox models. Conclusions: In RCTs of HER2-targeted agents in HER2+ MBC, PFS is moderately correlated with OS and treatment effects on PFS are modestly correlated with treatment effects on OS, similarly to first-line chemotherapy in MBC (Burzykowski et al JCO 2008). PFS does not completely substitute for OS.

A meta-analysis of endocrine therapy trials in early breast cancer (BC) evaluating the impact of obesity: Are aromatase inhibitors (AIs) optimal therapy in obese ER+ BC?

575

Background: Obesity is an adverse prognostic factor in BC. Mixed results are reported for the relative efficacy of AIs compared to tamoxifen (T) in obese ER+ BC patients. Our purpose was to conduct a meta-analysis of adjuvant randomised trials of AIs vs T assessing the impact of body mass index (BMI). Methods: We identified four studies evaluating BMI and endocrine therapy. Of these, 3 were randomised (non-steroidal AIs vs T) and were evaluable for the aggregation of results for DFS and OS in our meta-analysis. We extracted published data from ATAC, ABCSG-12 and BIG01-98, analyzed according to standard meta-analytic techniques. Results: A total of 11,383 patients were included in our study. BMI>25 is associated with reduced disease free survival (DFS) and a trend towards worse overall survival (OS) (Table 1). A significantly shorter DFS was seen for patients with BMI>25 treated with an AI while a trend was seen for OS. Reduced relative efficacy was seen for DFS for AIs compared to T for BMI<25 (HR=0.78; 95%CI 0.66- 0.91; p=0.002) and a trend for BMI>25 (HR=0.85; 95%CI 0.70- 1.02; p=0.08). The test for interaction was not significant (p=0.48), with similar results for OS for BMI<25 (HR=0.79; 95%CI 0.63-0.9; p=0.009) and BMI>25 (HR=0.98; 95%CI 0.61-1.60; p=0.95). The test for interaction was not significant (p=0.37). Notably, significant heterogeneity in patients treated with anastrozole and a BMI>25 did not allow a comparison between anastrozole and letrozole. Conclusions: BMI>25 has a negative prognostic effect in BC. AIs demonstrate improved outcomes in normal weight BC patients (BMI<25). Obesity was associated with observed relative reduced efficacy of AIs; however, we were not able to detect a significant interaction between BMI and treatment effect. Further analyses into the differing impact of type of AIs on BC outcomes in obese patients are warranted. [Table: see text]

The prognostic role of androgen receptor in early-stage breast cancer patients: A meta-analysis

528

Background: Androgen receptor (AR) expression has been observed in ~70% of breast cancer (BC) patients, but its prognostic role is not established yet. To assess this we performed a meta-analysis of studies that evaluated the impact of AR on disease free survival (DFS) and/or on overall survival (OS) in early stage BC. Methods: Published studies were identified by an electronic search on PubMed using the MeSH terms "breast neoplasm" and "androgen receptor" (up to June 2012). Identified studies were assessed against the following criteria for inclusion in the analysis: early stage BC and reported results of AR status in correlation with clinical outcome. We report combined HRs with 95% confidence intervals (CI) using AR negative patients as reference. Results: Twenty studies were eligible for the meta-analysis out of 493 initially identified and 12 among them, including 6,525 patients, were considered as evaluable (i.e., reporting enough information to allow aggregation of results). AR positivity was associated with lower risk of relapse in all breast cancer patients, and better overall survival in both univariate (U) and multivariate (M) analysis. AR prognostic impact in different subtypes was also assessed (see Table). Conclusions: Our analysis demonstrated that AR delivers prognostic information overall, serving as a positive prognostic factor in early stage BC. Further studies are needed to delineate its prognostic impact within the different subtypes of the disease. [Table: see text]

Use of mutational profiling of metastatic ER+/HER2- breast cancers and the coexistence of KRAS, MET, BRAF, and FGFR3 with PIK3CA mutations

11003

Background: ER+/HER2- breast cancers (BCs) constitute the most frequent BC subtype. Their response to endocrine therapy and degree of estrogen dependence are heterogeneous. There is little data available about the genetic changes associated with disease progression in this subtype. This information could facilitate drug development. Methods: A series of 132 ER+/HER2- BC patients diagnosed between 1982 and 2008, with known local-regional (n=10) or distant (n=98) relapse or both (n=24), and available FFPE blocks from their primary (P; n=132) and paired relapse (R; n=49) were identified at a single institution. ER and HER2 status were centrally confirmed. 120 mutations from 11 actionable genes and PTEN protein expression were determined using Fluidigm-based real-time PCR and IHC, respectively. Results: At primary diagnosis, median age was 57 years (27-90); median tumor size 2.5 cm (0.5-11); 75% had positive nodes, 26.5% were pre-menopausal; 80% received adjuvant hormonal treatment. Mutation frequency in P and R samples is presented in the Table. PIK3CA mutations were identified in 44% (58/132) P samples. HRAS, AKT1 and PIK3CA mutations were mutually exclusive. 62.5% (5/8) of KRAS-mutated, 75% (6/8) of MET-mutated, 100% (2/2) of BRAF-mutated and 33.3% (1/3) of FGFR3-mutated P had coexistent PIK3CA mutations. For the 49 evaluated pairs, high concordance for the mutations status was found between P and R. Conclusions: KRAS, BRAF, MET and FGFR3 mutations, found at relatively high frequency in this population of relapsed ER+/HER2- BCs, could represent clinically relevant targets and contribute to mechanisms of recurrence, particularly in PIK3CA-mutated BCs. Mutation profiling of additional paired samples is ongoing and clinical outcome data will be presented. [Table: see text]

Long-term (8 years) assessment of trastuzumab-related cardiac events in the HERA trial

525

Background: Trastuzumab-related cardiac dysfunction may occur in patients (pts) treated with adjuvant therapy and it is mostly reversible. We report the long-term outcome of pts with cardiac dysfunction treated with adjuvant trastuzumab (T) in the Herceptin Adjuvant (HERA) trial. Methods: HERA is a three-arm, randomized trial that compared 1 year or 2 years of T with observation (Obs) in women with HER2-positive early breast cancer (EBC). Eligible pts had a left ventricular ejection fraction (LVEF) ≥ 55% at study entry (i.e. after completion of (neo)adjuvant chemotherapy with or without radiotherapy). Cardiac function was closely monitored throughout the trial. This analysis at 8-year median follow-up considers pts randomly assigned to 1 year or 2 years of T therapy or observation. Results: 5102 pts were randomized to HERA. The “as treated” safety population is considered: 2 years T (N=1,673), 1 year T (N=1,682) and Obs (N=1,744). Cardiac events leading to T discontinuation in the 1-year and 2-year arms were observed in 5.2% and 9.4% of pts, respectively. Cardiac death, severe congestive heart failure (CHF) and confirmed significant LVEF drop remained low in all three arms (Table). In the 1 year T arm, 71.4% of pts with severe CHF, and 81.2% of pts with confirmed LVEF drop recovered cardiac function (at least 2 sequential LVEF assessments > 50%). The median time to recovery was 9.7 months and 6.3 months, respectively. In the 2 years T arm, 87.5% of pts with confirmed LVEF drop recovered cardiac function and median time to recovery was 8.3 months. Conclusions: At 8-year median follow-up the incidence of cardiac events during adjuvant T remains low and these events are mostly reversible. These results confirm low cardiac events when T is given as part of the adjuvant therapy for pts with HER2-positive EBC. Clinical trial information: NCT00045032. [Table: see text]

Correlation of molecular alterations with efficacy of everolimus in hormone-receptor–positive (HR+), HER2-negative advanced breast cancer: Preliminary results from BOLERO-2

LBA509

The full, final text of this abstract will be available at abstract.asco.org at 7:30 AM (EDT) on Monday, June, 3, 2013, and in the Annual Meeting Proceedings online supplement to the June 20, 2013, issue of Journal of Clinical Oncology. Onsite at the Meeting, this abstract will be printed in the Monday edition of ASCO Daily News.

Feasibility study of cationic liposome-encapsulated paclitaxel in combination with paclitaxel followed by FEC as induction therapy in HER2-negative breast cancer

e12008

Background: Cationic liposome-encapsulated paclitaxel , a tumor endothelial targeting agent (composition of paclitaxel combined with neutral and cationic lipids) has shown activity in metastatic triple-negative breast cancer (BC) in combination with paclitaxel (Awada et al. ESMO2010). No data exist in the non-metastatic setting. Methods: HER2-negative BC candidates for neoadjuvant chemotherapy were scheduled to receive 12 cycles of weeklycationic liposome-encapsulated paclitaxel 22mg/m2 plus paclitaxel 70mg/m2 followed by 3 cycles of FEC (Fluorouracil 500mg/m2, Epirubicin 100mg/m2, Cyclophosphamide 500mg/m2) every 3 weeks followed by surgery. Primary endpoint was percent (%) reduction in Magnetic Resonance Imaging (MRI) estimated tumor volume at the end of cationic liposome-encapsulated paclitaxel plus paclitaxel administration as compared to baseline. Safety, pathological complete response (pCR) defined as no residual tumor in breast and axillary nodes at surgery and correlation between % reduction in MRI estimated tumor volume and pCR were also evaluated. Results: Six patients with estrogen receptor (ER)-negative/HER2-negative and 9 with ER-positive/HER2-negative BC were included. Nine patients completed treatment as per protocol. Despite premedication and slow infusion rates, grade 3 hypersensitivity reactions to cationic liposome-encapsulated paclitaxel were observed during the 1st, 2nd, 3rd and 6th weekly infusion in 4 patients, respectively and required permanent discontinuation of the cationic liposome-encapsulated paclitaxel . Two patients stopped cationic liposome-encapsulated paclitaxel plus paclitaxel after 8 and 9 weeks due to clinical disease progression, two patients had grade 3 increase in transaminases and 1 patient grade 4 neutropenia. PCR was observed in 5 of the 6 ER-/HER2- and in none of the 8 ER+/HER2- BC patients. The median % reduction in MRI estimated tumor volume at the end of cationic liposome-encapsulated paclitaxel plus paclitaxel treatment was 90% (95% Confidence Interval: 69-99%), (p<0.001, sign test) for the 14 patients that underwent surgery; 99% (CI:87-100%) for patients with pCR and 84% (CI:50-95%) for patients with no pCR. Conclusions: The cationic liposome-encapsulated paclitaxel and paclitaxel combination showed promising preliminary activity as preoperative treatment, especially in ER-/HER2- patients. Further studies are warranted with need of premedication optimization. Clinical trial information: NCT01537536.

Targeting the PI3K/AKT/mTOR and Raf/MEK/ERK pathways in the treatment of breast cancer

Alterations of signal transduction pathways leading to uncontrolled cellular proliferation, survival, invasion, and metastases are hallmarks of the carcinogenic process. The phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) and the Raf/mitogen-activated and extracellular signal-regulated kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathways are critical for normal human physiology, and also commonly dysregulated in several human cancers, including breast cancer (BC). In vitro and in vivo data suggest that the PI3K/AKT/mTOR and Raf/MEK/ERK cascades are interconnected with multiple points of convergence, cross-talk, and feedback loops. Raf/MEK/ERK and PI3K/AKT/mTOR pathway mutations may co-exist. Inhibition of one pathway can still result in the maintenance of signaling via the other (reciprocal) pathway. The existence of such "escape" mechanisms implies that dual targeting of these pathways may lead to superior efficacy and better clinical outcome in selected patients. Several clinical trials targeting one or both pathways are already underway in BC patients. The toxicity profile of this novel approach of dual pathway inhibition needs to be closely monitored, given the important physiological role of PI3K/AKT/mTOR and Raf/MEK/ERK signaling. In this article, we present a review of the current relevant pre-clinical and clinical data and discuss the rationale for dual inhibition of these pathways in the treatment of BC patients.

CNS relapses in patients with HER2-positive early breast cancer who have and have not received adjuvant trastuzumab: a retrospective substudy of the HERA trial (BIG 1-01)

BACKGROUND

Several randomised trials have confirmed the benefit of adjuvant trastuzumab for patients with HER2-positive early breast cancer. However, concern has been expressed that adjuvant trastuzumab might be associated with an increased frequency of CNS relapses. We assessed the frequency and course of CNS relapses, either as first event or at any time, using data from the HERA trial.

METHODS

We estimated the cumulative incidence of first disease-free survival (DFS) events in the CNS versus other sites by competing risks analysis in patients with HER2-positive early breast cancer who had been randomly assigned to receive 1 year of trastuzumab or to observation in the HERA trial after a median follow-up of 4 years (IQR 3·5-4·8). To obtain further information about CNS relapse at any time before death, we circulated a data collection form to investigators to obtain standardised information about CNS events that occurred in all patients who had died before July, 2009. We estimated the cumulative incidence of CNS relapse at any time with a competing risks analysis.

RESULTS

Of 3401 patients who had been assigned to receive 1 year of trastuzumab or to observation, 69 (2%) had a CNS relapse as first DFS event and 747 (22%) had a first DFS event not in the CNS. The frequency of CNS relapses as first DFS event did not differ between the group given 1 year of trastuzumab (37 [2%] of 1703 patients) and the observation group (32 [2%] of 1698; p=0·55 [Gray's test]). 481 data collection forms were distributed, of which 413 (86%) were returned. The proportion of patients who had died and experienced a CNS relapse was numerically higher in the observation group (129 [57%] of 227) than in the group given trastuzumab for 1 year (88 [47%] of 186; p=0·06 [Gray's test]). Most CNS relapses were symptomatic (189 [87%] of 217).

CONCLUSION

Adjuvant trastuzumab does not increase the risk of CNS relapse in patients with HER2-positive early breast cancer.

FUNDING

None.

Pertuzumab: new hope for patients with HER2-positive breast cancer

BACKGROUND

Human epidermal growth factor receptor 2 (HER2) overexpression is detected in approximately 15% to 20% of all breast cancers (BCs). A revolutionary change in the prognosis of this subgroup of patients has occurred since trastuzumab therapy was introduced into daily clinical practice. However, because trastuzumab resistance is common, new molecules with complementary and/or synergistic mechanisms of action have been developed. Pertuzumab is a new anti-HER2 humanized monoclonal antibody that prevents the formation of HER2 dimers.

MATERIAL AND METHODS

A computer-based literature search was carried out using PubMed (keywords: breast neoplasm, dimerization, HER-2, pertuzumab); data reported at international meetings are included.

RESULTS

This paper describes pertuzumab's mechanism of action, safety, and role in HER2-positive BCs. It also explores the role of pertuzumab as a single agent or combined with trastuzumab by reviewing data from preclinical research to ongoing clinical trials. Recently published trials, particularly the CLEOPATRA study, highlight the efficacy, tolerability, and increase in disease-free survival associated with this novel agent when combined with trastuzumab.

CONCLUSION

The pertuzumab and trastuzumab anti-HER2 dual blockade is likely to represent a substantial advance for patients with HER2-positive BCs and a new milestone on the way to personalized medicine.

Abstract P5-18-02: Selective Crossover in Randomized Trials of Adjuvant Trastuzumab for Breast Cancer: Coping with Success

BACKGROUND: Disease-free survival (DFS) is often a primary endpoint of randomized trials of adjuvant therapies for breast cancer, but long-term follow-up of DFS and especially overall survival (OS) remain important. When the primary DFS results favor the experimental arm, patients (pts) assigned to the control group may select the option to crossover to receive the experimental treatment via protocol amendment. Such “selective crossover” disturbs the integrity of the randomized comparison for any efficacy endpoints that rely on further follow-up. Selective crossover, which is motivated by positive results having been observed in the current trial, is distinct from so-called “unplanned crossover,” which refers to non-adherence to protocol. In this abstract, we discuss the consequences of selective crossover for trials evaluating adjuvant trastuzumab, using the HERA (HERceptin Adjuvant) trial as an example, and present a variety of alternative analysis approaches.

METHODS: HERA enrolled 5102 women with HER2-positive early breast cancer who had completed all surgery and (neo)adjuvant chemotherapy to compare 1 or 2 years of trastuzumab treatment vs observation. After a positive first interim analysis at 1y median follow-up (MFU) showed that 1 year of trastuzumab significantly improved DFS vs observation [MJ Piccart-Gebhart et al; NEJM 2005], event-free patients in the observation group were offered crossover to receive trastuzumab. 885 (52%) of the 1698 pts in the observation group selectively crossed over to trastuzumab.

RESULTS: Previously reported intention-to-treat (ITT) analysis of HERA at 4y MFU showed a decreasing effectiveness of trastuzumab with respect to DFS compared with those at 2y MFU [L Gianni et al, Lancet Oncol 2011; I Smith et al, Lancet 2007]. In addition, the ITT analysis of OS at 4y MFU showed little effect of trastuzumab, while the analysis artificially censoring follow-up in the observation group at the time of selective crossover showed a substantial OS advantage for trastuzumab.

Phase I study of lonafarnib (SCH66336) in combination with trastuzumab plus paclitaxel in Her2/neu overexpressing breast cancer: EORTC study 16023

PURPOSE

This phase I study was performed to determine the maximum tolerated dose (MTD), dose-limiting toxicities (DLT), safety profile, recommended dose for phase II studies, the pharmacokinetics, and antitumor activity of the combination of lonafarnib (farnesyl transferase inhibitor), trastuzumab, and paclitaxel in Her2-positive advanced breast cancer.

METHODS

Twenty-three patients with Her2-overexpressing breast cancer received in the first cycle paclitaxel and trastuzumab and from cycle 2 onwards lonafarnib which was added to the combination. Dose-limiting toxicity (DLT) was determined during the second cycle.

RESULTS

The MTD and the recommended dose for phase II trials are lonafarnib: 250 mg/day [125 mg/bi-daily (BID)] continuously, paclitaxel: 175 mg/m² 3-h infusion every 3 weeks, and trastuzumab: 4 mg/kg loading dose and 2 mg/kg/week thereafter. The most frequently observed adverse events starting from cycle 1 onwards were alopecia, myalgia, sensory neuropathy, fatigue, arthralgia, leukocytopenia, and neutropenia. From cycle 2 onwards, additional adverse events appeared, such as diarrhea, nausea, dyspepsia, vomiting, and allergy. The mean systemic exposures of both lonafarnib and paclitaxel through all dose levels were higher in the regimen with all three study medications but with no statistically significant difference. Preliminary antitumor activity (CR + PR) was observed in 58% of all patients.

CONCLUSION

Lonafarnib can be safely combined and tolerated with full doses of paclitaxel and trastuzumab in Her2-positive advanced breast cancer patients. Promising preliminary antitumor activity warrants further evaluation of lonafarnib in combination with paclitaxel and trastuzumab in Her2-positive breast cancer.

Effects of everolimus (EVE) on disease progression in bone and bone markers (BMs) in patients (pts) with bone metastases (mets)

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Background: BOLERO-2, a multinational, double-blind, placebo-controlled, phase III study in postmenopausal women with estrogen-receptor–positive breast cancer (BC) refractory to nonsteroidal aromatase inhibitors (NSAIs), showed significant clinical benefits with the addition of EVE to exemestane (EXE) (Baselga J et al. NEJM2011 Epub). As bone resorption is an important factor in BC mets, it is interesting to study bone-related effects of EVE. In preclinical studies, mTOR inhibition was associated with decreased osteoclast survival and activity. Exploratory analyses in BOLERO-2 evaluated the effects of EVE vs placebo (PBO) on BM levels and BC progression in bone in pts with bone mets at baseline. Methods: Eligible pts were treated with EXE (25 mg once daily) and randomized (2:1) to EVE (10 mg once daily) or PBO. Bone turnover markers (BMs) were exploratory endpoints analyzed at 6 and 12 wks after treatment initiation and included bone-specific alkaline phosphatase, amino-terminal propeptide of type I collagen, and C-terminal cross-linking telopeptide of type I collagen. Progressive disease in bone (PDB) was defined as worsening of a preexisting bone lesion or a new bone lesion. Results: Baseline disease characteristics, including bone mets at baseline (n = 370, 76% EVE vs n = 184, 77% PBO), were well balanced between arms (N = 724), and baseline bisphosphonate use was not (44% EVE vs 55% PBO). At 12.5 mo median follow-up, progression-free survival (primary endpoint), overall response rate, and clinical benefit rate (p < 0.0001, all) were significantly higher with EVE (n = 485) vs PBO (n = 239). BM levels at 6 and 12 wks increased vs baseline with PBO but decreased with EVE. The cumulative incidence rate of BC PBD was lower for EVE vs PBO at day 60 (3.03% vs 6.16%, respectively), and this trend was sustained beyond 6 months. Updated results will be presented. All bone-related adverse events reported were grade 1-2 and occurred with similar frequency in EVE (2.9%)- and PBO (3.8%)-treated patients. Conclusions: Exploratory analyses from BOLERO-2 suggest that adding EVE has beneficial effects on bone turnover and BC progression in bone in pts receiving EXE therapy for NSAI-refractory BC.

Comparison of molecular (BluePrint and MammaPrint) and pathological subtypes for breast cancer among the first 800 patients from the EORTC 10041/BIG 3-04 (MINDACT) trial

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Background: Biology has become the main driver of breast cancer therapy. Intrinsic biological subtypes by gene expression profiling have been identified. Pathology can be used to define surrogates of these subtypes but these are not always concordant, which may lead to different treatment plans. We investigated the concordance between BluePrint (BP) + MammaPrint (MP) (micro array based) breast cancer subtypes and pathological surrogates (based on ER, PR, HER2 and Ki67). Contrary to the Perou gene set (evolved into PAM50), BluePrint was trained using pathological data. Methods: Using available data (centrally assessed pathology and genomic) from the MINDACT pilot phase (Rutgers et al 2011) 621 tumors were analyzed. Two pathology classifications were used: one with 4 categories and one with 5 categories (Goldhirsch et al 2011). Based on BP 3 subtypes are formed: Luminal, HER2 and Basal. The Luminal subtype is further split into Luminal A (MP low risk) and Luminal B (MP high risk). Results: See table. Conclusions: All pathological Basal cases are BP Basal, apart from 1 BP HER2 case. Of the BP Basal cases, 15 are not pathological Basal: 1 is Luminal A, 11 are Luminal B (of which 8 are IHC ER/PR borderline (≥1% and < 10%)) and 3 are HER2. All pathological Luminal (A & B) that are BP HER2 are HER2- by TargetPrint. 25 of the 26 pathological HER2+ that are BP Luminal A are ER+. Most discordant cases are seen within the Luminal subtype, indicating that Ki67 discriminates Luminal A vs. B differently than MammaPrint does. The observed subtype discrepancies reveal potential important impact for treatment-decision making. MINDACT will provide important information. [Table: see text]