TSPYL5 SNPs: association with plasma estradiol concentrations and aromatase expression

We performed a discovery genome-wide association study to identify genetic factors associated with variation in plasma estradiol (E2) concentrations using DNA from 772 postmenopausal women with estrogen receptor (ER)-positive breast cancer prior to the initiation of aromatase inhibitor therapy. Association analyses showed that the single nucleotide polymorphisms (SNP) (rs1864729) with the lowest P value (P = 3.49E-08), mapped to chromosome 8 near TSPYL5. We also identified 17 imputed SNPs in or near TSPYL5 with P values < 5E-08, one of which, rs2583506, created a functional estrogen response element. We then used a panel of lymphoblastoid cell lines (LCLs) stably transfected with ERα with known genome-wide SNP genotypes to demonstrate that TSPYL5 expression increased after E2 exposure of cells heterozygous for variant TSPYL5 SNP genotypes, but not in those homozygous for wild-type alleles. TSPYL5 knockdown decreased, and overexpression increased aromatase (CYP19A1) expression in MCF-7 cells, LCLs, and adipocytes through the skin/adipose (I.4) promoter. Chromatin immunoprecipitation assay showed that TSPYL5 bound to the CYP19A1 I.4 promoter. A putative TSPYL5 binding motif was identified in 43 genes, and TSPYL5 appeared to function as a transcription factor for most of those genes. In summary, genome-wide significant SNPs in TSPYL5 were associated with elevated plasma E2 in postmenopausal breast cancer patients. SNP rs2583506 created a functional estrogen response element, and LCLs with variant SNP genotypes displayed increased E2-dependent TSPYL5 expression. TSPYL5 induced CYP19A1 expression and that of many other genes. These studies have revealed a novel mechanism for regulating aromatase expression and plasma E2 concentrations in postmenopausal women with ER(+) breast cancer.

RC0639: phase II study of paclitaxel, trastuzumab, and lapatinib as adjuvant therapy for early stage HER2-positive breast cancer

Lapatinib adds to the efficacy of trastuzumab in preclinical models and also in the neo-adjuvant setting. This study assesses the safety and feasibility of adding lapatinib to paclitaxel and trastuzumab (THL) as part of the adjuvant therapy for HER2-positive breast cancer (HER2+ BC). In this single-arm phase II study, patients with stages I–III HER2+ BC received standard anthracycline-based chemotherapy followed by weekly taxane, with concurrent standard trastuzumab, plus daily lapatinib for a total of 12 months. The primary endpoint was symptomatic congestive heart failure, secondary endpoints included overall safety. A total of 109 eligible patients were enrolled. Median follow-up is 4.3 years. No patients experienced congestive heart failure while on treatment. Mean left ventricular ejection fraction at baseline and at the end of THL were 63.6 % (N = 109, SD = 5.7) and 59.8 % (N = 98, SD = 8.1), respectively [mean change −3.95 % (N = 98, SD = 8.3), p < 0.001]. One hundred and two patients initiated post-AC treatment; of them, 31 % experienced grade 3 (no G4) diarrhea with lapatinib at 750 mg/day. The addition of lapatinib to paclitaxel and trastuzumab following AC does not add cardiac toxicity. Lapatinib dose of 750 mg/day in combination with standard chemotherapy plus trastuzumab has acceptable overall tolerability.

Immunohistochemistry and fluorescence in situ hybridization assessment of HER2 in clinical trials of adjuvant therapy for breast cancer (NCCTG N9831, BCIRG 006, and BCIRG 005)

A comprehensive, blinded, pathology evaluation of HER2 testing in HER2-positive/negative breast cancers was performed among three central laboratories. Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) analyses were performed on 389 tumor blocks from three large adjuvant trials: N9831, BCIRG-006, and BCIRG-005. In 123 cases, multiple blocks were examined. HER2 status was defined according to FDA-approved guidelines and was independently re-assessed at each site. Discordant cases were adjudicated at an on-site, face-to-face meeting. Results across three independent pathologists were concordant by IHC in 351/381 (92 %) and FISH in 343/373 (92 %) blocks. Upon adjudication, consensus was reached on 16/30 and 18/30 of discordant IHC and FISH cases, respectively, resulting in overall concordance rates of 96 and 97 %. Among 155 HER2-negative blocks, HER2 status was confirmed in 153 (99 %). In the subset of 102 HER2-positive patients from N9831/BCIRG-006, primary blocks from discordant cases were selected, especially those with discordant test between local and central laboratories. HER2 status was confirmed in 73 (72 %) of these cases. Among 118 and 113 cases with IHC and FISH results and >1 block evaluable, block-to-block variability/heterogeneity in HER2 results was seen in 10 and 5 %, respectively. IHC−/FISH− was confirmed for 57/59 (97 %) primary blocks from N9831 (locally positive, but centrally negative); however, 5/22 (23 %) secondary blocks showed HER2 positivity. Among 53 N9831 patients with HER2-normal disease adjudicated as IHC−/FISH—(although locally positive), there was a non-statistically significant improvement in disease-free survival with concurrent trastuzumab compared to chemotherapy alone (adjusted hazard ratio 0.34; 95 % CI, 0.11–1.05; p = 0.06). There were similar agreements for IHC and FISH among pathologists (92 % each). Agreement was improved at adjudication (96 %). HER2 tumor heterogeneity appears to partially explain discordant results in cases initially tested as positive and subsequently called negative.

Phase II randomized study of trastuzumab emtansine versus trastuzumab plus docetaxel in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer

PURPOSE

Trastuzumab emtansine (T-DM1), an antibody-drug conjugate composed of the cytotoxic agent DM1 conjugated to trastuzumab via a stable thioether linker, has shown clinical activity in single-arm studies enrolling patients with human epidermal growth factor receptor 2 (HER2) -positive metastatic breast cancer (MBC) whose disease had progressed on HER2-targeted therapy in the metastatic setting.

PATIENTS AND METHODS

Patients (N = 137) with HER2-positive MBC or recurrent locally advanced breast cancer were randomly assigned to trastuzumab plus docetaxel (HT; n = 70) or T-DM1 (n = 67) as first-line treatment until disease progression or unacceptable toxicity. Primary end points were investigator-assessed progression-free survival (PFS) and safety. Key secondary end points included overall survival (OS), objective response rate (ORR), duration of objective response, clinical benefit rate, and quality of life.

RESULTS

Median PFS was 9.2 months with HT and 14.2 months with T-DM1 (hazard ratio, 0.59; 95% CI, 0.36 to 0.97); median follow-up was approximately 14 months in both arms. ORR was 58.0% (95% CI, 45.5% to 69.2%) with HT and 64.2% (95% CI, 51.8% to 74.8%) with T-DM1. T-DM1 had a favorable safety profile versus HT, with fewer grade ≥ 3 adverse events (AEs; 46.4% v 90.9%), AEs leading to treatment discontinuations (7.2% v 34.8%), [corrected] and serious AEs (20.3% v 25.8%). Preliminary OS results were similar between treatment arms; median follow-up was approximately 23 months in both arms.

CONCLUSION

In this randomized phase II study, first-line treatment with T-DM1 for patients with HER2-positive MBC provided a significant improvement in PFS, with a favorable safety profile, versus HT.

Impact of premenopausal status at breast cancer diagnosis in women entered on the placebo-controlled NCIC CTG MA17 trial of extended adjuvant letrozole

BACKGROUND

MA17 showed improved outcomes in postmenopausal women given extended letrozole (LET) after completing 5 years of adjuvant tamoxifen.

PATIENTS AND METHODS

Exploratory subgroup analyses of disease-free survival (DFS), distant DFS (DDFS), overall survival (OS), toxic effects and quality of life (QOL) in MA17 were performed based on menopausal status at breast cancer diagnosis.

RESULTS

At diagnosis, 877 women were premenopausal and 4289 were postmenopausal. Extended LET was significantly better than placebo (PLAC) in DFS for premenopausal [hazard ratio (HR) = 0.26, 95% confidence interval (CI) 0.13-0.55; P = 0.0003] and postmenopausal women (HR = 0.67; 95% CI 0.51-0.89; P = 0.006), with greater DFS benefit in those premenopausal (interaction P = 0.03). In adjusted post-unblinding analysis, those who switched from PLAC to LET improved DDFS in premenopausal (HR = 0.15; 95% CI 0.03-0.79; P = 0.02) and postmenopausal women (HR = 0.45; 95% CI 0.22-0.94; P = 0.03).

CONCLUSIONS

Extended LET after 5 years of tamoxifen was effective in pre- and postmenopausal women at diagnosis, and significantly better in those premenopausal. Women premenopausal at diagnosis should be considered for extended adjuvant therapy with LET if menopausal after completing tamoxifen.

Quality assessment metrics for whole genome gene expression profiling of paraffin embedded samples

BACKGROUND

Formalin fixed, paraffin embedded tissues are most commonly used for routine pathology analysis and for long term tissue preservation in the clinical setting. Many institutions have large archives of Formalin fixed, paraffin embedded tissues that provide a unique opportunity for understanding genomic signatures of disease. However, genome-wide expression profiling of Formalin fixed, paraffin embedded samples have been challenging due to RNA degradation. Because of the significant heterogeneity in tissue quality, normalization and analysis of these data presents particular challenges. The distribution of intensity values from archival tissues are inherently noisy and skewed due to differential sample degradation raising two primary concerns; whether a highly skewed array will unduly influence initial normalization of the data and whether outlier arrays can be reliably identified.

FINDINGS

Two simple extensions of common regression diagnostic measures are introduced that measure the stress an array undergoes during normalization and how much a given array deviates from the remaining arrays post-normalization. These metrics are applied to a study involving 1618 formalin-fixed, paraffin-embedded HER2-positive breast cancer samples from the N9831 adjuvant trial processed with Illumina's cDNA-mediated Annealing Selection extension and Ligation assay.

CONCLUSION

Proper assessment of array quality within a research study is crucial for controlling unwanted variability in the data. The metrics proposed in this paper have direct biological interpretations and can be used to identify arrays that should either be removed from analysis all together or down-weighted to reduce their influence in downstream analyses.

Analysis of regional timelines to set up a global phase III clinical trial in breast cancer: the adjuvant lapatinib and/or trastuzumab treatment optimization experience

PURPOSE

This study measured the time taken for setting up the different facets of adjuvant lapatinib and/or trastuzumab treatment optimization (ALTTO), an nternational phase III study being conducted in 44 participating countries.

METHODS

Time to regulatory authority (RA) approval, time to ethics committee/institutional review board (EC/IRB) approval, time from study approval by EC/IRB to first randomized patient, and time from first to last randomized patient were prospectively collected in the ALTTO study. Analyses were conducted by grouping countries into either geographic regions or economic classes as per the World Bank's criteria.

RESULTS

South America had a significantly longer time to RA approval (median: 236 days, range: 21-257 days) than Europe (median: 52 days, range: 0-151 days), North America (median: 26 days, range: 22-30 days), and Asia-Pacific (median: 62 days, range: 37-75 days). Upper-middle economies had longer times to RA approval (median: 123 days, range: 21-257 days) than high-income (median: 47 days, range: 0-112 days) and lower-middle income economies (median: 57 days, range: 37-62 days). No significant difference was observed for time to EC/IRB approval across the studied regions (median: 59 days, range 0-174 days). Overall, the median time from EC/IRB approval to first recruited patient was 169 days (range: 26-412 days).

CONCLUSION

This study highlights the long time intervals required to activate a global phase III trial. Collaborative research groups, pharmaceutical industry sponsors, and regulatory authorities should analyze the current system and enter into dialogue for optimizing local policies. This would enable faster access of patients to innovative therapies and enhance the efficiency of clinical research.

Exemestane versus anastrozole in postmenopausal women with early breast cancer: NCIC CTG MA.27--a randomized controlled phase III trial

PURPOSE

In patients with hormone-dependent postmenopausal breast cancer, standard adjuvant therapy involves 5 years of the nonsteroidal aromatase inhibitors anastrozole and letrozole. The steroidal inhibitor exemestane is partially non-cross-resistant with nonsteroidal aromatase inhibitors and is a mild androgen and could prove superior to anastrozole regarding efficacy and toxicity, specifically with less bone loss.

PATIENTS AND METHODS

We designed an open-label, randomized, phase III trial of 5 years of exemestane versus anastrozole with a two-sided test of superiority to detect a 2.4% improvement with exemestane in 5-year event-free survival (EFS). Secondary objectives included assessment of overall survival, distant disease-free survival, incidence of contralateral new primary breast cancer, and safety.

RESULTS

In the study, 7,576 women (median age, 64.1 years) were enrolled. At median follow-up of 4.1 years, 4-year EFS was 91% for exemestane and 91.2% for anastrozole (stratified hazard ratio, 1.02; 95% CI, 0.87 to 1.18; P = .85). Overall, distant disease-free survival and disease-specific survival were also similar. In all, 31.6% of patients discontinued treatment as a result of adverse effects, concomitant disease, or study refusal. Osteoporosis/osteopenia, hypertriglyceridemia, vaginal bleeding, and hypercholesterolemia were less frequent on exemestane, whereas mild liver function abnormalities and rare episodes of atrial fibrillation were less frequent on anastrozole. Vasomotor and musculoskeletal symptoms were similar between arms.

CONCLUSION

This first comparison of steroidal and nonsteroidal classes of aromatase inhibitors showed neither to be superior in terms of breast cancer outcomes as 5-year initial adjuvant therapy for postmenopausal breast cancer by two-way test. Less toxicity on bone is compatible with one hypothesis behind MA.27 but requires confirmation. Exemestane should be considered another option as up-front adjuvant therapy for postmenopausal hormone receptor-positive breast cancer.

Prognostic and predictive value of tumor vascular endothelial growth factor gene amplification in metastatic breast cancer treated with paclitaxel with and without bevacizumab; results from ECOG 2100 trial

PURPOSE

Clinically validated biomarkers for anti-angiogenesis agents are not available. We have previously reported associations between candidate VEGFA single-nucleotide polymorphisms (SNP) and overall survival (OS) in E2100. The associations between tumor VEGFA amplification and outcome are evaluated here.

EXPERIMENTAL DESIGN

E2100 was a phase III trial comparing paclitaxel with or without bevacizumab for patients with metastatic breast cancer. FISH to assess gene amplification status for VEGFA was conducted on paraffin-embedded tumors from 363 patients in E2100. Evaluation for association between amplification status and outcomes was conducted.

RESULTS

Estrogen receptor (ER)+ or progesterone receptor (PR)+ tumors were less likely to have VEGFA amplification than ER/PR- tumors (P = 0.020). VEGFA amplification was associated with worse OS (20.2 vs. 25.3 months; P = 0.013) in univariate analysis with a trend for worse OS in multivariate analysis (P = 0.08). There was a significant interaction between VEGFA amplification, hormone receptor status, and study arm. Patients with VEGFA amplification and triple-negative breast cancers (TNBC) or HER2 amplification had inferior OS (P = 0.047); amplification did not affect OS for those who were ER+ or PR+ and HER2-. Those who received bevacizumab with VEGFA amplification had inferior progression-free survival (PFS; P = 0.010) and OS (P = 0.042); no association was seen in the control arm. Test for interaction between study arm and VEGFA amplification with OS was not significant.

CONCLUSION

VEGFA amplification in univariate analysis was associated with poor outcomes; this was particularly prominent in HER2+ or TNBCs. Additional studies are necessary to confirm the trend for poor OS seen on multivariate analysis for patients treated with bevacizumab.

How relevant is hormone receptor status in the context of outcome to HER2-positive breast cancer?

Clinical outcome of patients with breast cancer is based on patient and tumor-related factors. The relevant tumor-related factors include anatomical extent and biology. Of the prognostic and predictive biological markers available, hormone receptors (defined as estrogen and progesterone receptors) and HER2 receptors, have been independently validated. Pertinent questions to be addressed include their combined impact on prognosis, their relevance in terms of sites of metastases, and whether they change in primary versus recurrent tumors. Although these questions are being addressed in clinical trials, epidemiological results, such as those derived from the National Comprehensive Cancer Network dataset, add perspective to our understanding of these two most relevant biological prognostic/predictive markers.

New developments in metastatic breast cancer: integrating recent data into clinical practice

The treatment of metastatic breast cancer continues to be a challenging area for medical oncologists. Breast tumors are classified into several groups based on immunohistochemistry: those that are estrogen-receptor–positive and human epidermal growth factor receptor 2 (HER2)-negative; those that are HER2-positive and either estrogen-receptor–positive or estrogen-receptor–negative; and those that are negative for the estrogen receptor, progesterone receptor, and HER2 (known as triple-negative). These biologic factors are an important component of the risk assessment and treatment strategy. Management goals for advanced disease are to target treatment to the specific biology in a more effective way, and to add in targeted agents that may improve the effectiveness of standard therapies, such as hormone therapy and chemotherapy. There are several new therapies that are changing outcome for patients with metastatic disease, such as eribulin, pertuzumab, and ado-trastuzumab emtansine. It is critical to understand the appropriate dosing schedules of novel agents and how best to combine them with standard therapy. Ongoing clinical trials are evaluating new treatment approaches, as well as ways to identify biologic subsets that might benefit from particular therapies. Investigational agents include glembatumumab vedotin, neratinib, and margetuximab.

Abstract P1-12-06: N0937 (Alliance): Preliminary results of a phase II clinical trial of cisplatin and the novel agent brostallicin in patients with metastatic triple negative breast cancer (mTNBC)

Background: TNBC is characterized by unique molecular profiles, aggressive behavior, poor prognosis and lack of targeted therapies. Brostallicin is a novel synthetic compound from the class of DNA minor groove binding (MGB) anti-cancer agents, making it a logical agent to evaluate in the setting of TNBC. It retains activity in cancer cells resistant to alkylating agents, topoisomerase I inhibitors and is fully active against DNA-mismatch repair deficient tumor cells. Preclinical models using cell lines demonstrate that cells expressing relatively high glutathione/glutathione S-transferase (GSH/GST) levels are more susceptible to brostallicin's antitumor efficacy. Cisplatin administration increases expression of GSH/GST in tumor cells, thus leading to an increased anti-tumor efficacy of brostallicin.

Methods: Phase II cooperative group study in pts with mTNBC (³18 years of age with measurable metastatic disease, ER/PR ≤1%; HER2 negative, who had received 0–4 prior chemotherapy regimens in the metastatic setting; with adequate hematologic, renal and hepatic functions; and no active CNS metastases; prior exposure to cisplatin allowed). Cisplatin on Day 1 followed by brostallicin on Day 2, repeated every 21 days. Aim: efficacy of brostallicin and proof of concept of its mechanism of action in mTNBC. Primary endpoint progression-free survival (PFS) at 3 months with 89% power (0.10 significance level) to detect an absolute difference of 20% (35% vs 55%), based on the median PFS of 60 days in pts with mTNBC from the N0234 trial of erlotinib and gemcitabine as 1st/2nd line. Secondary endpoints include ORR, duration of response (DOR), 6-month PFS, OS and AE profile. Tertiary endpoints include assessment of 1) GSH levels prior to the administration of cisplatin and of brostallicin; and 2) the prevalence of BCRA-1 mutation by IHC in primary or metastatic tumor.

Results: Study closed on 3/28/12 and it accrued 48 pts (median f/u 2.3 mo; 0–15.3); 33 pts are off treatment and 15 pts remain on study; 38 pts evaluable for response, and 43 evaluable for AEs. 50% received therapy as 3rd to 5th line. Median number of cycles 2.5 (off-treatment: 2; on-treatment: 3, range 0–15). There are currently 5 confirmed responses (4 PR and 1 CR); DOR: 2.8–13.3 months. The 6-mo PFS is currently 19.2% (95% CI: 8.9%, 41.3%); the median TTP is 3.0 months (95% CI: 1.7 months, 4.2 months). Current data are premature to determine the primary endpoint (3-mo PFS) but we expect to report such data by November 2012. Current toxicity data: 69.7% G3/4 heme toxicity. Non-heme toxicity G3 (30.2%) and G4 (9.3)% (febrile neutropenia 21%; fatigue G3 14%); and no G5 non-heme AE.

Conclusions: The current preliminary data of this trial show very encouraging activity of this regimen (brostallicin plus cisplatin) in mTNBC. Near 1/3 of pts are still currently receiving therapy, and we expect to provide primary and additional secondary endpoint data at SABCS 2012.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-12-06.

Abstract P1-05-24: Pharmacologic reversion of epigenetic silencing of the PRKD1 promoter blocks breast tumor cell invasion and metastasis

Epigenetic silencing of tumor suppressing genes by promoter-specific DNA methylation is common in many types of cancer. As an early event, this process has been well shown to promote tumor initiation and progression; however little is known how such epigenetic silencing can contribute to tumor metastasis. The PRKD1 gene encodes Protein Kinase D1 (PKD1), a serine/threonine kinase expressed in epithelial cells of the normal mammary gland that maintains the epithelial phenotype of normal breast cells and prevents epithelial-to-mesenchymal transition (EMT). PKD1 is also a critical suppressor of tumor cell invasion and is silenced in expression and activity during breast tumor progression. Here, we show that aberrant methylation of PRKD1 promoter region is not only correlated with the silencing of its expression but is also associated with invasiveness of breast cancer cell lines and with aggressiveness of breast tumors. Using the highly invasive MDA-MB-231 cells, we show that the inhibition of PRKD1 promoter methylation with the DNA methyltransferase inhibitor decitabine restores PKD1 expression and significantly decreases their invasive abilities in vitro. More importantly, in a tumor xenograft model it dramatically blocks tumor spread and metastasis to the lung in a PKD1-dependent fashion. Our data suggest that the status of epigenetic regulation of the PRKD1 promoter can provide valid information on the invasiveness of breast tumors, and therefore could serve as an early diagnostic marker. Moreover, targeted upregulation of PKD1 expression may be used as a therapeutic approach to reverse the invasive phenotype of breast cancer cells.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-05-24.

North central cancer treatment group (NCCTG) N0537: phase II trial of VEGF-trap in patients with metastatic breast cancer previously treated with an anthracycline and/or a taxane

INTRODUCTION

Angiogenesis is an established target for the treatment of MBC. Aflibercept (VEGF-Trap) is a humanized fusion protein, which binds VEGF-A, VEGF-B, and PIGF-1 and -2.

PATIENTS AND METHODS

A 2-stage phase II study with primary end points of confirmed tumor response and 6-month progression-free survival (PFS). If either end point was promising after the initial 21 patients, an additional 20 patients would be enrolled. Measurable disease, <2 previous chemotherapy treatments, previous anthracycline or taxane therapy, and Eastern Cooperative Oncology Group performance status of 0 or 1 were required. Aflibercept was given at a dose of 4 mg/kg intravenous every 14 days.

RESULTS

Twenty-one patients were enrolled; 71% had visceral disease, 57% were estrogen receptor negative, 19% had HER2(+) disease with previous trastuzumab treatment, and 33% had 2 previous chemotherapy regimens. Partial response rate was 4.8% (95% confidence interval [CI], 0.1%-23.8%) and 6-month PFS was 9.5% (95% CI, 1.2%-30.4%). Neither primary end point met efficacy goals and the study was terminated. A median of 3 cycles was given. Median PFS was 2.4 months. Common grade 3 or 4 adverse events were hypertension (33%), fatigue (19%), dyspnea (14%), and headache (14%). Two cases of severe left ventricular dysfunction were noted.

CONCLUSIONS

Aflibercept did not meet efficacy goals in patients previously treated with MBC. Toxicity was as expected for anti-VEGF therapy.

Ixabepilone-associated peripheral neuropathy: data from across the phase II and III clinical trials

PURPOSE

Dose-limiting neuropathy is a major adverse event associated with most of the microtubule-stabilizing agent-based chemotherapy regimens. Ixabepilone, a semisynthetic analogue of the natural epothilone B, has activity against a wide range of tumor types. Peripheral neuropathy (PN), associated with ixabepilone treatment, is usually mild to moderate, predominantly sensory and cumulative. Preclinical studies demonstrate that ixabepilone and taxanes produce a similar neurotoxicity profile.

METHODS

We searched databases of phase II/III clinical trials involving patients receiving ixabepilone as a monotherapy or in combination with capecitabine for incidences of neuropathy. Potential risk factors for grade 3/4 PN were identified by a Cox regression analysis on a dataset of 1,540 patients with different tumor types across multiple studies.

RESULTS

Rates for incidence of ixabepilone-induced severe PN (Common Terminology Criteria for Adverse Events grade 3/4) ranged from 1% in early untreated breast cancer up to 24% in heavily pretreated metastatic breast cancer; grade 4 PN was rare (≤ 1%). Common symptoms included numbness, paresthesias, and sometimes dysesthesias. Cox regression analysis identified only preexisting neuropathy as a risk factor for increased ixabepilone-associated PN. The management of PN has been primarily through dose adjustments (dose delays and/or dose reduction). Patients had resolution of their neuropathy within a median time of 5 to 6 weeks.

CONCLUSIONS

PN is a dose-limiting toxicity associated with ixabepilone treatment, is reversible in most patients, and can be managed with dose reduction and delays.

Final overall survival (OS) and safety analyses of RIBBON-2, a randomized phase III trial of bevacizumab (BEV) versus placebo (PL) combined with second-line chemotherapy (CT) for HER2-negative BEV-naive metastatic breast cancer (MBC)

100

Background: Combining BEV with CT significantly improved progression-free survival (primary endpoint) in the E2100, AVADO, and RIBBON-1 trials in the 1st-line setting and the RIBBON-2 trial in the 2nd-line setting. Primary efficacy and safety results from RIBBON-2 have been published; here we present final OS results. Methods: Eligible patients (pts) had MBC that had progressed on 1st-line CT without BEV. 2nd-line CT (taxane, gemcitabine, capecitabine, or vinorelbine) was chosen before 2:1 randomization to CT with either BEV (10 mg/kg q2w or 15 mg/kg q3w) or PL continued until progression. Stratification factors were 2nd-line CT, hormone receptor status, and time from MBC diagnosis to 1st progression. All pts could receive BEV at progression. The primary endpoint was PFS. Final analysis of OS, a secondary endpoint, in the intent-to-treat population was planned after 557 events and provided 80% power to detect a hazard ratio (HR) of 0.77 (median OS increased from 14.0 to 18.2 months) at α=0.04. Results: At the time of data cutoff (Oct. 31, 2011), 184 (82%) of 225 pts in the CT/PL arm and 376 (82%) of 459 pts in the CT/BEV arm had died. BEV was administered in subsequent treatment lines in 12% vs 6% of pts, respectively. There was no difference in OS between treatment arms: HR 1.013 (95% CI 0.845–1.215), log-rank p=0.8843. Median OS was 17.8 months with CT/PL vs 18.6 months with CT/BEV. The 1-year OS rates were 69% vs 71%, respectively. Subgroup analyses by CT cohort showed HRs ranging from 0.86 (95% CI 0.58–1.29) in the capecitabine cohort (n=144) to 1.44 (95% CI 0.82–2.53) in the vinorelbine cohort (n=76). HRs were close to 1 for the two largest CT cohorts (taxane and gemcitabine). Exploratory analysis in the subgroup of patients with triple-negative MBC showed a HR of 0.85 (95% CI 0.58–1.26). Updated safety results were similar to those previously reported from the primary analysis. There were fewer fatal adverse events in the CT/BEV arm (1.5%) than in the CT/PL arm (3.2%). Conclusions: Final OS results from RIBBON-2 reveal no difference between treatment arms. No new safety signals were observed.

Obesity at diagnosis is associated with inferior outcomes in hormone receptor-positive operable breast cancer

BACKGROUND

Obesity has been associated with inferior outcomes in operable breast cancer, but the relation between body mass index (BMI) and outcomes by breast cancer subtype has not been previously evaluated.

METHODS

The authors evaluated the relation between BMI and outcomes in 3 adjuvant trials coordinated by the Eastern Cooperative Oncology Group that included chemotherapy regimens with doxorubicin and cyclophosphamide, including E1199, E5188, and E3189. Results are expressed as hazard ratios (HRs) from Cox proportional hazards models (HR >1 indicates a worse outcome). All P values are 2-sided.

RESULTS

When evaluated as a continuous variable in trial E1199, increasing BMI within the obese (BMI, ≥ 30 kg/m(2)) and overweight (BMI, 25-29.9 kg/m(2)) ranges was associated with inferior outcomes in hormone receptor-positive, human epidermal growth receptor 2 (HER-2)/neu-negative disease for disease-free survival (DFS; P = .0006) and overall survival (OS; P = .0007), but not in HER-2/neu-overexpressing or triple-negative disease. When evaluated as a categorical variable, obesity was associated with inferior DFS (HR, 1.24; 95% confidence interval [CI], 1.06-1.46; P = .0008) and OS (HR, 1.37; 95% CI, 1.13-1.67; P = .002) in hormone receptor-positive disease, but not other subtypes. In a model including obesity, disease subtype, and their interaction, the interaction term was significant for OS (P = .02) and showed a strong trend for DFS (P = .07). Similar results were found in 2 other trials (E5188, E3189).

CONCLUSIONS

In a clinical trial population that excluded patients with significant comorbidities, obesity was associated with inferior outcomes specifically in patients with hormone receptor-positive operable breast cancer treated with standard chemohormonal therapy.

Neuropathy is not associated with clinical outcomes in patients receiving adjuvant taxane-containing therapy for operable breast cancer

PURPOSE

Neuropathy is a common and potentially disabling complication of adjuvant taxane therapy. Recent studies have identified candidate single nucleotide polymorphisms associated with taxane-induced neuropathy. Therefore, we sought to determine whether neuropathy was associated with breast cancer recurrence in a clinical trial population who received adjuvant taxane therapy.

PATIENTS AND METHODS

Trial E1199 included 4,554 eligible women with operable breast cancer who received up to four cycles of doxorubicin and cyclophosphamide every 3 weeks followed by paclitaxel 175 mg/m(2) every 3 weeks for four cycles (P3), paclitaxel 80 mg/m(2) weekly for 12 cycles (P1), docetaxel 100 mg/m(2) every 3 weeks for four cycles (D3), or docetaxel 35 mg/m(2) weekly for 12 cycles (D1). A Cox proportional hazards model was used to determine the relationship between neuropathy and disease-free survival (DFS), overall survival (OS), and recurrence-free survival (RFS) by treating neuropathy status as a time dependent covariate and using a landmark analysis.

RESULTS

Of 4,554 patients who received at least one taxane dose, grade 2 to 4 neuropathy developed in 18%, 22%, 15%, and 13% of patients in the P3, P1, D3, and D1 arms, respectively. In a model that included age, race, obesity, menopausal status, tumor size, nodal status, treatment arm, neuropathy, and hyperglycemia, no significant relationship was found between neuropathy and DFS, OS, or RFS.

CONCLUSION

There was no association between taxane-induced neuropathy and outcome.

Reexpression of tumor suppressor, sFRP1, leads to antitumor synergy of combined HDAC and methyltransferase inhibitors in chemoresistant cancers

Metastatic solid tumors are aggressive and mostly drug resistant, leading to few treatment options and poor prognosis as seen with clear cell renal cell carcinoma (ccRCC) and triple-negative breast cancer (TNBC). Therefore, the identification of new therapeutic regimes for the treatment of metastatic disease is desirable. ccRCC and TNBC cell lines were treated with the HDAC inhibitor romidepsin and the methyltransferase inhibitor decitabine, two epigenetic modifying drugs approved by the U.S. Food and Drug Administration for the treatment of various hematologic malignancies. Cell proliferation analysis, flow cytometry, quantitative PCR, and immunoblotting techniques were used to evaluate the antitumor synergy of this drug combination and identify the reexpression of epigenetically silenced tumor suppressor genes. Combinatorial treatment of metastatic TNBC and stage IV ccRCC cell lines with romidepsin/decitabine leads to synergistic inhibition of cell growth and induction of apoptosis above levels of individual drug treatments alone. Synergistic reexpression of the tumor suppressor gene secreted frizzled-related protein one (sFRP1) was observed in combinatorial drug-treated groups. Silencing sFRP1 (short hairpin RNA) before combinatorial drug treatment showed that sFRP1 mediates the growth inhibitory and apoptotic activity of combined romidepsin/decitabine. Furthermore, addition of recombinant sFRP1 to ccRCC or TNBC cells inhibits cell growth in a dose-dependent manner through the induction of apoptosis, identifying that epigenetic silencing of sFRP1 contributes to renal and breast cancer cell survival. Combinatorial treatment with romidepsin and decitabine in drug resistant tumors is a promising treatment strategy. Moreover, recombinant sFRP1 may be a novel therapeutic strategy for cancers with suppressed sFRP1 expression.

Six cycles of doxorubicin and cyclophosphamide or Paclitaxel are not superior to four cycles as adjuvant chemotherapy for breast cancer in women with zero to three positive axillary nodes: Cancer and Leukemia Group B 40101

PURPOSE

The ideal duration of adjuvant chemotherapy for patients with lower risk primary breast cancer is not known. Cancer and Leukemia Group B trial 40101 was conducted using a phase III factorial design to define whether six cycles of a chemotherapy regimen are superior to four cycles. We also sought to determine whether paclitaxel (T) is as efficacious as doxorubicin/cyclophosphamide (AC), but with reduced toxicity.

PATIENTS AND METHODS

Between 2002 and 2008, the study enrolled women with operable breast cancer and zero to three positive nodes. Patients were randomly assigned to either four or six cycles of either AC or T. Study stratifiers were estrogen receptor/progesterone receptor (ER/PgR), human epidermal growth factor receptor 2 (HER2), and menopausal status. After 2003, all treatment was administered in dose-dense fashion. The primary efficacy end point was relapse-free survival (RFS).

RESULTS

A total of 3,171 patients were enrolled; 94% were node-negative and 6% had one to three positive nodes. At a median follow-up of 5.3 years, the 4-year RFS was 90.9% and 91.8% for six and four cycles, respectively. The adjusted hazard ratio (HR) of six to four cycles regarding RFS was 1.03 (95% CI, 0.84 to 1.28; P=.77). The 4-year OS was 95.3% and 96.3% for six and four cycles, respectively, with an HR of six to four cycles of 1.12 (95% CI, 0.84 to 1.49; P=.44). There was no interaction between treatment duration and chemotherapy regimen, ER/PgR, or HER2 status on RFS or OS.

CONCLUSION

For women with resected primary breast cancer and zero to three positive nodes, we found no evidence that extending chemotherapy regimens of AC or single-agent T from four to six cycles improves clinical outcome.

Phase II interventional study (N0337) of capecitabine in combination with vinorelbine and trastuzumab for first- or second-line treatment of HER2-positive metastatic breast cancer: a north central cancer treatment group trial

BACKGROUND

We conducted a multiinstitutional phase II study of capecitabine in combination with vinorelbine and trastuzumab in patients eligible to receive first- or second-line treatment for human epidermal growth factor receptor type 2 (HER2)-positive (HER2(+)) metastatic breast cancer (MBC).

PATIENTS AND METHODS

The study was designed to test that the true confirmed response rate (CRR) was at most 45% vs. a true CRR of at least 65%. Between March 2005 and June 2008, eligible patients received capecitabine 825 mg/m² orally on days 1 to 14, vinorelbine 25 mg/m² intravenously on days 1 and 8 every 3 weeks, and trastuzumab 8 mg/kg intravenously on day 1 week 1 and 6 mg/kg every 3 weeks. The main outcome measure was CRR.

RESULTS

Of 47 women accrued, 45 were evaluable. This design required at least 25 confirmed responses in the 45 evaluable patients for the treatment to be considered promising. Thirty women (67%) achieved a confirmed response; 25 women (56%) had a confirmed partial response (PR); 5 women (11%) had confirmed complete responses (CRs). Median progression-free survival (PFS) was 11.3 months (95% confidence interval [CI], 8.4-16.7 months). Median overall survival was 28.5 months (95% CI, 24.8-36.4 months).

CONCLUSIONS

This triplet combination demonstrated promising activity in patients with HER2(+) MBC.

CALGB 40502/NCCTG N063H: Randomized phase III trial of weekly paclitaxel (P) compared to weekly nanoparticle albumin bound nab-paclitaxel (NP) or ixabepilone (Ix) with or without bevacizumab (B) as first-line therapy for locally recurrent or metastatic breast cancer (MBC)

CRA1002

Background: Weekly P is superior to q 3 week (wk) dosing, and adding B improves progression free survival (PFS) (E2100). Ix is a potent epothilone that can be effective after microtubule inhibitor resistance. NP is a novel albumin-bound formulation of P with promising activity in the first-line MBC setting. In this phase III trial, the efficacy of weekly Ix or NP is compared to P, in combination with B in patients (pts) with chemotherapy (CTX) naïve MBC. Toxicity including >Grade 2 sensory neuropathy (SN) is compared to P. Methods: Pts were randomized 1:1:1 to receive P (90 mg/m2), Ix (16 mg/m2) or NP (150 mg/m2) on a 3 wk on, 1 wk off schedule, stratified by prior adjuvant taxane use and hormone receptor status. B was initially given to all pts, but became optional in 3/2011 and was added to stratification. The primary end point of PFS is defined as time from randomization to progression or all-cause death. With a target N=900 pts, the study was powered to detect a hazard ratio (HR) of 1.36 (median PFS 10 vs 13.6 mos). Eligibility included no prior CTX for MBC, >12 mos from adjuvant P and measurable disease. Results: 799 pts were enrolled between 11/08-11/11 (283 to P, 271 to NP, 245 to Ix); 98% received B. 72% had ER+ disease, 44% received adjuvant P. At the 1st interim analysis (165 events) the comparison of Ix to P crossed the futility boundary (FB) and accrual to Ix was closed. At the 2nd interim analysis (236 events), NP to P crossed the FB and the study was closed on 11/30/11. Median PFS was 10.4, 9.6 and 7.6 mos for P, NP and Ix, with HRs (95% CIs) of 0.94 (0.73-1.22) and 0.66 (0.51-0.84) for P to NP and Ix respectively. Grade 2+ SN was 48% for NP, 44% for Ix and 37% for P; Grade 3+ hematologic toxicity was 49% for NP, 20% for Ix, and 12% for P. Conclusions: In pts with CTX naive MBC, both NP and Ix are highly unlikely to be superior to P for PFS (when all are combined with B), and in combination with B, weekly P is the better tolerated drug. Toxicity including SN was greater in each experimental arm compared to P. Updated data will be presented, and correlative studies will be reported at a future date.

NSABP B-38: Definitive analysis of a randomized adjuvant trial comparing dose-dense (DD) AC→paclitaxel (P) plus gemcitabine (G) with DD AC→P and with docetaxel, doxorubicin, and cyclophosphamide (TAC) in women with operable, node-positive breast cancer

LBA1000

Background: The primary aims were to determine whether adjuvant DD AC→PG will be superior to DD AC→P as well as to TAC in DFS and to compare the relative DFS of TAC and DD AC→P. Secondary endpoints include survival and toxicity. Methods: From Nov 3, 2004 to May 3, 2007, 4894 women were randomized; 1630 to TAC (docetaxel [T] 75 mg/m2, doxorubicin [A] 50 mg/m2, cyclophosphamide [C] 500 mg/m2 q3 wks x 6), 1634 to DD AC→P (A 60 mg/m2 and C 600 mg/m2 q2 wks x 4 followed by P 175 mg/m2 q2 wks x 4), and 1630 to DD AC→PG (A 60 mg/m2 and C 600 mg/m2 q2 wks x 4 → P 175 mg/m2 + G 2000 mg/m2q2 wks x 4). Primary G-CSF support was required and erythropoiesis-stimulating agents (ESA) were used at investigator discretion. 52% were postmenopausal, 65% had 1 - 3 positive nodes, and 80% had HR+ breast cancer. Log-rank tests were used for pair-wise comparisons of the primary (DFS) and secondary (OS) endpoints among the three treatment arms. Results: With 64 months median follow-up, 5-year DFS in DD AC→PG group was 80.6% compared with 82.2% in DD AC→P group (HR=1.1; p=0.27) and 80.1 % (HR=0.97; p=0.71) in TAC group. 5-year OS was 90.8% in DD AC→PG group as compared with 89.1% (HR=.89; p=0.25) in DD AC→P group and 89.6 % (HR=0.90; p=0.32) in TAC group. HR for DFS and OS of DD AC→P vs. TAC were 0.89 (p=0.14) and 1.01 (p=0.92) respectively. Toxicities for TAC, DD AC→P, DD AC→PG, respectively: febrile neutropenia (Gr 3/4: 9%, 4%, 4% [p<0.001]), sensory neuropathy (Gr 3/4: <1%, 7%, 6% [p<0.001]), diarrhea (Gr 3/4: 8 %, 2%, 2% [p<0.001]). Hgb was <10 in 12%, 26%, 33% with ESA use in 35.2%, 47%, 51.6% and transfusions in 3.7%, 6.3%, 9.4%. Deaths on treatment: N=13, 5, 7 (p=0.2). AML/MDS: N=5, 8, 11. All cycles completed in 91% for TAC and 88% for DD regimens. Conclusions: Addition of G to DD AC→P did not improve outcomes. No significant differences in efficacy endpoints were identified between DD AC→P and TAC, though toxicity profiles differed. Funding: NCI PHS U10-CA-37377, -69974, -12027, -69651 and NCCTG U10-CA25224, with additional funding from Eli Lilly & Company, and Amgen, Inc.

Intraventricular (IVe) topotecan for women with neoplastic meningitis (NM) associated with "responsive" malignancies

2015

Background: A prior study of intra-CSF topotecan (TOPO) for unselected pts w/ NM reported PFS 6 mo of 19%, and OS of 15 wks (Groves, NeuroOncol 2008;10:208). We postulated that greater activity might occur in pts w/ malignancies considered sensitive to topoisomerase inhibitors. Methods: We reviewed outcome of women with NM and adenocarcinoma of the breast, ovary or lung receiving IVe TOPO (0.4 mg 2x/wk x 4wk, Q wk x 4, Q 2wk x 2, Q mo x 3, Q 2mo x 3, and Q 3mo x 4) until progression (PROG) or adverse events (AE). All had baseline CSF cytology, and MRI of brain and spine. CSF cytology was obtained at each treatment (Rx), and brain/spine MRI Q 3mo. Neuro-specific PROG was defined as recurrent + CSF cytology; PROG of NM on MRI; all-cause neurologic worsening; pt refusal; or death. PFS/OS were measured from 1st TOPO Rx. All pts signed consent; the study was IRB approved. Results: 17 women (breast -12; lung-3; ovary - 2) were treated via Ommaya reservoirs; 7 (41%) had VP shunts w/ valves, adjusted for Rx. Median (med) age was 53 (41-79), and KPS 70 (50-90). At presentation, 11(65%) had + CSF cytology and 14 (82%) had NM on MRI [brain-11 (65%); spine-10 (59%)]. 15 (88%) had no prior intrathecal Rx. 13 pts (76%) received focal RT for CNS disease, and 8 (47%), chemotherapy for extracranial disease. Med.number of Rx were 13/pt (range, 3-50); med. duration of TOPO Rx was 14 wks (range, 1-109). Med. neuro-specific PFS was 13 wks; PFS6 was 41%, and PFS12, 29 %. Med. OS was 33 wks (range, 5-180), w/ 4 alive at 13+, 30+, 33+, and 180+ wks. 4 pts (24%) lived > 95 wks. Of 11 w/ baseline + CSF cytology, 7 (64%) cleared CSF of malignant cells (med. duration clear = 47 wk (range, 9-104). AE included arachnoiditis (18%), leukoencephalopathy (18%), and Ommaya infections (12%). Rx was stopped for neuro PROG (29%); systemic PROG (23%); refusal (18%); AE (12%); or persistent negative CSF (6%); 12% are still on Rx. Conclusions: Promising activity of IVe TOPO was observed in women with NM from breast, lung and ovarian cancer. PFS 6 and 12, OS and cytologic response were twice that noted in prior studies of NM pts w/ unselected malignancies. This data supports our plan for a phase II study targeting this select cohort.

Correlation between the DCIS score and traditional clinicopathologic features in the prospectively designed E5194 clinical validation study

1005

Background: We previously reported that in the E5194 clinical trial patients with ductal carcinoma in situ (DCIS) treated with wide local excision (WLE) without radiation (RT), the DCIS Score was significantly associated with 10 year risk of an ipsilateral breast event (IBE - recurrence of in situ or invasive carcinoma), whether evaluated as a continuous or categorical variable (P=0.02 for both). Here we evaluate correlation between DCIS Score and clinicopathologic (CP) features and if DCIS Score provides independent recurrence risk information. Methods: The study population included 327 women with DCIS prospectively selected for treatment with WLE without RT, including low-intermediate grade tumors ≤2.5 cm or high-grade ≤1 cm. CP variables included age, menopausal status, tamoxifen treatment (used in 29%) and expert centrally determined tumor size, grade, comedo necrosis, tumor type, and margin status. The association between DCIS Score and CP variables was examined by spearman rank correlation, and proportional hazards regression models were used to determine variables significantly associated with IBE. Results: Lesion size (p=0.009) and menopausal status (p=0.03) were significantly associated with IBE, while grade (p=0.69) and comedo necrosis (p=0.47) were not. DCIS Score was significantly associated with IBE after adjustment for CP features and tamoxifen use (p=0.02). DCIS Score was moderately correlated with grade (rs=0.46; 95% CI 0.37,0.54), percentage comedo necrosis (rs=0.49; CI 0.41,0.57), and lesion size (rs=0.18; CI 0.08,0.29) but not other features. Exploratory analyses in all CP subgroups, including the multicomponent Van Nuys Prognostic Index, showed a wide range of DCIS Scores in each subgroup. Concordance of the grades among readers was low: local vs parent central, 68%; local vs central nuclear grade, 45%; parent central vs central nuclear grade, 37%. Conclusions: DCIS Score is moderately correlated with grade, comedo necrosis, and tumor size. DCIS Score provides recurrence risk information independent of these features and identifies subjects with DCIS who are at high risk for local invasive and in-situ local recurrence after WLE alone.

A combination of pertuzumab, trastuzumab, and vinorelbine for first-line treatment of patients with HER2-positive metastatic breast cancer: An open-label, two-cohort, phase II study (VELVET)

TPS653

Background: Pertuzumab (P) is a humanized monoclonal antibody directed against the dimerization domain of HER2: it prevents HER2 heterodimerization and thus activation of downstream signaling. Since P targets a different epitope than trastuzumab (H), a more comprehensive HER2 blockade is achieved by combining the two agents. Data from CLEOPATRA showed improved efficacy for P and H plus docetaxel. The combination of P and H has not yet been assessed with other chemotherapy partners in the metastatic setting. H plus vinorelbine (V) has shown comparable efficacy to H plus docetaxel but with a superior safety profile. VELVET will assess the overall response rate (ORR) of P with H+V in first-line patients (pts) with HER2-positive MBC. Co-administration of P and H within the same infusion bag will also be investigated as this could increase pt convenience by reducing administration and observation time. Methods: VELVET is a multicenter, open-label, two-cohort, Phase II trial. Pts with HER2-positive LABC or MBC not previously treated in the metastatic setting with non-hormonal anticancer therapy are eligible. Pts must have an LVEF >55% at baseline and an ECOG PS of 0 or 1. Study enrollment started in January 2012. A total of 210 pts will be included. Based on statistical assumptions, 95 pts must be evaluable per cohort, which assumes a withdrawal rate around 10%. Pts in Cohort 1 (the first 105 pts enrolled) will receive P and H sequentially and pts in Cohort 2 (the next 105 pts) will receive P and H in the same infusion bag at Cycle 2 onwards if drug administration in Cycle 1 was well tolerated. V will be given in both cohorts. Treatment duration is until disease progression or unacceptable toxicity. Study dose: P: 840 mg loading dose, 420 mg q3w (iv); H: 8 mg/kg loading dose, 6 mg/kg q3w (iv), and V: 25 mg/m2 Day 1 and 8 (first cycle) then 30−35 mg/m2 Day 1 and 8 q3w (iv) (dose escalation at investigator’s discretion). The primary endpoint is ORR by independent assessment. Secondary endpoints include investigator assessment of ORR, time to response, duration of response, PFS, time to progression, overall survival, safety and tolerability, and QoL.

Phase III open-label, randomized, multicenter study of NKTR-102 versus treatment of physician's choice (TPC) in patients (pts) with locally recurrent or metastatic breast cancer (MBC) previously treated with an anthracycline, a taxane, and capecitabine (ATC)

TPS1140^

Background: NKTR-102 is a topoisomerase I inhibitor-polymer conjugate that hydrolyzes to provide continuous exposure to SN-38. A phase 2 trial of single-agent NKTR-102 was conducted in pts with 3rd-line MBC; 2 schedules (q14d; q21d) investigated a dose of 145 mg/m2. ORR was 29% (including 3% CR) with the prior ATC subset demonstrating an ORR of 31%. Dosing q21d was better tolerated; in this arm, median PFS and OS equaled 5.3m and 13.1m, respectively. Trial Design: Pts will be randomized 1:1 to receive single-agent NKTR-102 or TPC in an open-label, randomized, multicenter phase 3 study in pts with advanced breast cancer. Key Entry Criteria: Adult females, with ECOG 0 or 1 with adequate liver, kidney and marrow function. All pts must have received prior therapy with ATC (these drugs can be administered in the neo/adjuvant or locally advanced/metastatic setting). Prior A is not mandated if contraindicated. Prior toxicities must have resolved to ≤ Grade 1 (except sensory neuropathy ≤ Grade 2; complete resolution of prior diarrhea). Pts with brain metastases may be eligible, if lesions are stable for prior 3 weeks without steroids. Methods: Primary efficacy endpoint is OS. Secondary endpoints include: ORR by RECIST v1.1, clinical benefit rate (ORR+SD > 6 months), PFS and QoL. NKTR-102 is given IV at 145 mg/m2 over 90-min every 21 days without premedications. Pts randomized to TPC receive 1 of the following: eribulin, ixabepilone, vinorelbine, gemcitabine, paclitaxel, docetaxel or nab-paclitaxel (the agent must be available at the treating institution). Pts are stratified by region, prior eribulin and receptor status (TNBC, Her2+ or Other). Target Accrual: ~840 pts will be required for sufficient events to occur in the planned follow-up time; OS will be compared using a two-sided log-rank test; 1 interim analysis will occur when 50% of the deaths are reported. PK sampling is performed in a subset of pts. CTCs (isolated by Apocell ApoStream technology) are serially assessed for potential predictive markers of response and toxicity. Enrollment is expected to remain open until late 2013.

NSABP B-38: Definitive analysis of a randomized adjuvant trial comparing dose-dense (DD) AC followed by paclitaxel (P) plus gemcitabine (G) with DD AC followed by P and with docetaxel, doxorubicin, and cyclophosphamide (TAC) in women with operable, node-positive breast cancer

LBA1000

The full, final text of this abstract will be available at abstract.asco.org at 12:01 AM (EDT) on Monday, June 4, 2012, and in the Annual Meeting Proceedings online supplement to the June 20, 2012, issue of Journal of Clinical Oncology. Onsite at the Meeting, this abstract will be printed in the Monday edition of ASCO Daily News.

10-year update of E2197: Phase III doxorubicin/docetaxel (AT) versus doxorubicin/cyclophosphamide (AC) adjuvant treatment of LN+ and high-risk LN- breast cancer and the comparison of the prognostic utility of the 21-gene recurrence score (RS) with clinicopathologic features

1021

Background: At 5 years, AT did not improve disease free survival or overall survival and RS was a more accurate predictor of relapse than standard clinicopathologic characteristics for patients with hormone receptor (HR) positive tumors. Methods: A Phase III Intergroup trial tested adjuvant AT vs. AC. Women with 1-3 N + or N - and T-size > 1cm were randomized to 4 cycles of AT (60 mg/m2/60 mg/ m2) or AC (60 mg/m2/600 mg/m2) q 3 wk x 4. Patients(pts) with ER + and/ or PR + tumors received tam for 5 yrs. Pts were stratified by nodal, HR (ER+ PR+, ER+PR-, ER-PR+, ER-PR-, ER/PR unk) and menopausal status. The primary endpoint was DFS. A sample of 465 pts with HR + breast cancer with 0 to 3 positive axillary nodes who did (N =116) or did not have a recurrence had tumor tissue evaluated using the 21- gene assay. Grade and HR expression were evaluated locally and centrally. Results: 2952 pts were randomized between 7/30/98 and 1/21/00. 2883 were eligible and analyzable. Arms were balanced for age, HR, menopause, nodes, surgery, grade and T-size: median age 51; 64% ER +; 65% LN-; grade: 10% low, 38% int., 46% high; and median T-size - 2.0 cm. At a median follow-up of 11.5 years the DFS/OS results are shown in the table below. RS was a highly significant predictor of recurrence including node negative and node positive disease (P < .0001) and predicted recurrence more accurately than clinical variables. Conclusions: At 11.5 yrs. median follow-up, there remains no difference in DFS or OS, although there continue to be fewer events in the AT arm in the prespecified ER/PR negative subgroup. At 10 years, the RS continues to be a more accurate predictor of relapse than standard clinical features. [Table: see text]

Randomized phase II study of two doses of pixantrone in patients with metastatic breast cancer (N1031, Alliance)

1083

Background: Pixantrone (Pix) is a novel aza-anthracenedione with structural similarities to mitoxantrone and promising activity against non-Hodgkin’s lymphoma. Due to the lack of iron binding it is theorized to exhibit less cardiotoxicity than the anthracyclines. Methods: N1031 is a phase II RCT of 2 schedules of Pix, in pts with MBC. Group A pts received 180mg/m2 IV q3 wks, and group B pts 85mg/m2 IV on days 1, 8, 15 q4 wks. Eligibility included prior exposure to anthracyclines and/or taxanes, and 1 to 3 regiments in the metastatic setting (minimum of 2 if no prior adjuvant therapy given). Due to lack of long term cardiac safety data no more than 12 cycles were allowed. Frequent cardiac imaging was performed per protocol. Primary endpoint was RR and secondary endpoints included PFS, OS, safety, and QOL. Planned sample size was 25 pts per group. Results: In total 46 pts were evaluable (23 per group), mean age 55.5 yrs (range 38-79), 37% PS 0, 52% PS 1, and 11% PS 2. 80% of pts had prior exposure to doxorubicin, 72% had prior (neo)-adjuvant therapy, 76% were ER+ and 57% received prior HT. Number of prior metastatic regiments was: 1 (28%), 2 (61%) and 3 (11%). Most common adverse events (%) of any grade were: alopecia (74), anemia (74), fatigue (85), nausea (67), ANC decrease (87), and skin disorder (41). Grade 3-4 adverse events (%) at least possibly attributed to Pix and occurring in at least 2 pts were: ANC decrease (57), fatigue (9), increased AST (4%). One pt from each group (4%) had a grade 3 decrease in EF. There were no major differences between the two groups except for more oral mucositis in group A (35% vs 4%). Median number of cycles was 3 in group A (range 1-12) and 2 in group B (range 1-8). There was only 1 confirmed tumor response per group (4%,95% CI: 0.1-22%) prompting early termination of the trial. The median PFS was 2.7 mo (95% CI: 1.8-3.8), and the median OS was 8.9 mo (95% CI: 7.5-N/A). Conclusions: Pixantrone has insufficient activity in patients with MBC exposed to prior anthracyclines and/or taxanes. Adverse events were similar to prior experience with Pix. There were no major differences between the 2 schedules of administration. There was no significant cardiac toxicity seen in this trial. Correlative studies are underway.

Phase I study of panobinostat (LBH589) and letrozole in post-menopausal women with metastatic breast cancer

e13501

Background: Loss of estrogen receptor alpha gene expression has been associated with insensitivity to endocrine therapy in human breast cancer patients. Histone deacetylase (HDAC) inhibitors have recently been found to restore sensitivity to the estrogen receptor by modulation of the estrogen and progesterone receptors. This had been shown with both aromatase and tamoxifen refractory and in triple negative cell lines . We performed a Phase I study of the combination of LBH589 (panobinostat) and letrozole to evaluate safety and tolerability in patients with metastatic breast cancer prior to the performance of a phase II trial. Methods: We enrolled postmenopausal women with metastatic breast cancer, ECOG PS 0 or 1, ANC>1500/mm3, platelets>100,000/mm3, normal total bilirubin, and ALT/AST adequate laboratory tests were eligible. Letrozole dose was 2.5 mg/day orally. Dose of LBH589: Level 1, 20 mg orally three times weekly; Level 2, 30 mg orally three times a week. Results: 12 patients (dose level 1:6 patients, dose level 2: 6 patients) have been enrolled. 43 cycles of treatment have been given to these12 patients. Initial cohort of 3 patients at the 20 mg dose level had no dose limiting toxicity (DLT). At the 30 mg dose level 3/6 patients had DLT (thrombocytopenia grade 1: 2 pts; grade 3:1 pt; grade 4: 1 pt; and diarrhea grade 3: 1 pt. One pt at the 30 mg dose level has a confirmed partial response and remains on study after 6 cycles of treatment. Subsequent cohort of 3 patients had 1 dose DLT with doubling of the creatinine. The main DLT was thrombocytopenia in 3/6 pts at the 30 mg dose level. Conclusions: The recommended dose for phase II testing of LBH589 is 20 mg orally 3 times per week in combination with standard dose letrozole.

CALGB 40502/NCCTG N063H: Randomized phase III trial of weekly paclitaxel (P) compared to weekly nanoparticle albumin bound nab-paclitaxel (NP) or ixabepilone (Ix) with or without bevacizumab (B) as first-line therapy for locally recurrent or metastatic breast cancer (MBC)

CRA1002

The full, final text of this abstract will be available at abstract.asco.org at 12:01 AM (EDT) on Monday, June 4, 2012, and in the Annual Meeting Proceedings online supplement to the June 20, 2012, issue of Journal of Clinical Oncology. Onsite at the Meeting, this abstract will be printed in the Monday edition of ASCO Daily News.

A randomized phase III double-blinded placebo-controlled trial of first-line chemotherapy and trastuzumab with or without bevacizumab for patients with HER2/neu-overexpressing metastatic breast cancer (HER2+ MBC): A trial of the Eastern Cooperative Oncology Group (E1105)

605

Background: Pre-clinical and nonrandomized clinical data support synergy of the combination of bevacizumab and trastuzumab. We conducted a randomized double-blinded phase III trial of chemotherapy/trastuzumab ± bevacizumab to evaluate efficacy (PFS after treatment initiation) of the addition of bevacizumab in first-line treatment of HER2+ MBC. Methods: Days 1, 8 and 15 paclitaxel ± carboplatin were administered with trastuzumab and either placebo or bevacizumab 10 mg/kg every 2 weeks for a total of 6 months. Antibody therapy was then continued without chemo every 3 weeks, until disease progression or unacceptable toxicity. Disease assessments were performed every 3 months. Results: Ninety-six of the planned 489 analyzable patients (pts) were accrued between 2007 and 2009, at which time the study terminated due to poor accrual. Seventy % of pts were post-menopausal, 60% had ER+/HER2+ BC. Median age was 55 years (28-80). Outcomes and toxicities are summarized on the tables below. Median follow-up was 30 months. Conclusions: The combination of chemotherapy, trastuzumab, and bevacizumab did not significantly increased toxicity, and was overall safe and well tolerated. No significant differences in clinical benefit were observed between both treatment arms. Data on CTCs and Quality of Life will be presented at the meeting. This study was conducted by the Eastern Cooperative Oncology Group (Robert L. Comis, MD, Chair) and supported in part by Public Health Service Grants CA23318, CA66636, CA21115, CA32291, CA31946, CA49957, CA27525, CA14548, CA17145, CA32102, CA25224, CA49. [Table: see text] [Table: see text]

Potential for the embryonic morphogen Nodal as a prognostic and predictive biomarker in breast cancer

Introduction

The re-emergence of the tumour growth factor-beta (TGF-beta)-related embryonic morphogen Nodal has recently been reported in several different human cancers. In this study, we examined the expression of Nodal in a series of benign and malignant human breast tissues to determine the clinical significance of this expression and whether Nodal could represent a potential therapeutic target in breast cancer.

Methods

Tissue sections from 431 therapeutically naive patients diagnosed with benign or malignant breast disease were stained for Nodal by immunohistochemistry and analysed in a blinded manner. The degree of Nodal staining was subsequently correlated with available clinical data, such as diagnoses and disease stage. These tissue findings were further explored in breast cancer cell lines MDA-MB-231 and MDA-MB-468 treated with a Nodal blocking antibody to determine biological effects for target validation.

Results

A variable degree of Nodal staining was detected in all samples. The intensity of Nodal staining was significantly greater in undifferentiated, advanced stage, invasive breast cancer compared with benign breast disease or early stage breast cancer. Treatment of human breast cancer cells in vitro with Nodal blocking antibody significantly reduced proliferation and colony-forming ability in soft agar, concomitant with increased apoptosis.

Conclusions

These data suggest a potential role for Nodal as a biomarker for disease progression and a promising target for anti-Nodal therapy in breast cancer.

Prognostic value of biologic subtype and the 21-gene recurrence score relative to local recurrence after breast conservation treatment with radiation for early stage breast carcinoma: results from the Eastern Cooperative Oncology Group E2197 study

The present study was performed to evaluate the significance of biologic subtype and 21-gene recurrence score relative to local recurrence and local-regional recurrence after breast conservation treatment with radiation. Eastern Cooperative Oncology Group E2197 was a prospective randomized clinical trial that compared two adjuvant systemic chemotherapy regimens for patients with operable breast carcinoma with 1-3 positive lymph nodes or negative lymph nodes with tumor size >1.0 cm. The study population was a subset of 388 patients with known 21-gene recurrence score and treated with breast conservation surgery, systemic chemotherapy, and definitive radiation treatment. Median follow-up was 9.7 years (range = 3.7-11.6 years). The 10-year rates of local recurrence and local-regional recurrence were 5.4 % and 6.6 %, respectively. Neither biologic subtype nor 21-gene Recurrence Score was associated with local recurrence or local-regional recurrence on univariate or multivariate analyses (all P ≥ 0.12). The 10-year rates of local recurrence were 4.9 % for hormone receptor positive, HER2-negative tumors, 6.0 % for triple negative tumors, and 6.4 % for HER2-positive tumors (P = 0.76), and the 10-year rates of local-regional recurrence were 6.3, 6.9, and 7.2 %, respectively (P = 0.79). For hormone receptor-positive tumors, the 10-year rates of local recurrence were 3.2, 2.9, and 10.1 % for low, intermediate, and high 21-gene recurrence score, respectively (P = 0.17), and the 10-year rates of local-regional recurrence were 3.8, 5.1, and 12.0 %, respectively (P = 0.12). For hormone receptor-positive tumors, the 21-gene recurrence score evaluated as a continuous variable was significant for local-regional recurrence (hazard ratio 2.66; P = 0.03). The 10-year rates of local recurrence and local-regional recurrence were reasonably low in all subsets of patients. Neither biologic subtype nor 21-gene recurrence score should preclude breast conservation treatment with radiation.

Abstract 4926: Modeling the transcriptome landscape of HER2+ breast cancer

Motivation: Overexpression of HER2 (the product of the ERBB2 gene) occurs in about 15% of all breast tumors. We have undertaken to use next generation transcriptome sequencing technology to identify genomic features that are unique to HER2+ tumors. Interactome mapping was then used to integrate the genes associated with these features into a transcriptome landscape model, with a view towards identifying nodes of interaction that might be targeted in HER2+ tumors. Methods: We performed 50nt paired-end RNA-sequencing for 24 breast tumors: 8 each HER2+, ER+, triple negatives (TN). In addition to breast adenocarcinomas, we also sequenced 8 early passage non-transformed HMEC cell lines as normal controls. Reads from RNA sequencing were aligned to the genome and exon junctions using TopHat software. Gene counts were summarized and annotations were performed using our in-house programs. Tukey's test was used to obtain genes or transcripts that are specific to HER2 tumor group compared to other tumors/normal. A combination of bioinformatics softwares and algorithms were used to identify SNVs. Results: Only 13527 genes with median gene count greater than 16 reads in at least one of the 4 groups were considered for differential gene expression and splicing analysis. Some 696 genes were differentially expressed in HER2+ tumors compared to ER+, TN tumors and HMECs. We identified 272 alternately spliced transcripts for which the HER2+ tumors exhibited a mean transcript expression ratio significantly different from the means of other tumor groups. We also identified 4735 expressed single nucleotide variants that are uniquely associated with HER2+ tumors compared to other tumors/normal groups. Among these 3579/4735 sequence polymorphisms were not present in the 1000 genome germline sequence database or in the dbSNP132 database of naturally occurring germline polymorphisms. Integration of all the genes obtained from genomic feature analyses (differential expression, alternative splicing, single nucleotide variance) has been carried out to indentify biological processes that are specific to the HER2+ tumor subtype. Key nodes and pathways that are specific to HER2+ tumors will be evaluated for association with clinical outcome in a large series of patients who have received HER2-targeted therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4926. doi:1538-7445.AM2012-4926

Detection of redundant fusion transcripts as biomarkers or disease-specific therapeutic targets in breast cancer

Fusion genes and fusion gene products are widely employed as biomarkers and therapeutic targets in hematopoietic cancers, but their applications have yet to be appreciated in solid tumors. Here, we report the use of SnowShoes-FTD, a powerful new analytic pipeline that can identify fusion transcripts and assess their redundancy and tumor subtype-specific distribution in primary tumors. In a study of primary breast tumors, SnowShoes-FTD was used to analyze paired-end mRNA-Seq data from a panel of estrogen receptor (ER)(+), HER2(+), and triple-negative primary breast tumors, identifying tumor-specific fusion transcripts by comparison with mRNA-Seq data from nontransformed human mammary epithelial cell cultures plus the Illumina Body Map data from normal tissues. We found that every primary breast tumor that was analyzed expressed one or more fusion transcripts. Of the 131 tumor-specific fusion transcripts identified, 86 were "private" (restricted to a single tumor) and 45 were "redundant" (distributed among multiple tumors). Among the redundant fusion transcripts, 7 were unique to ER(+) tumors and 8 were unique to triple-negative tumors. In contrast, none of the redundant fusion transcripts were unique to HER2(+) tumors. Both private and redundant fusion transcripts were widely expressed in primary breast tumors, with many mapping to genomic loci implicated in breast carcinogenesis and/or risk. Our finding that some fusion transcripts are tumor subtype-specific suggests that these entities may be critical determinants in the etiology of breast cancer subtypes, useful as biomarkers for tumor stratification, or exploitable as cancer-specific therapeutic targets.

Deep Sequence Analysis of Non-Small Cell Lung Cancer: Integrated Analysis of Gene Expression, Alternative Splicing, and Single Nucleotide Variations in Lung Adenocarcinomas with and without Oncogenic KRAS Mutations

KRAS mutations are highly prevalent in non-small cell lung cancer (NSCLC), and tumors harboring these mutations tend to be aggressive and resistant to chemotherapy. We used next-generation sequencing technology to identify pathways that are specifically altered in lung tumors harboring a KRAS mutation. Paired-end RNA-sequencing of 15 primary lung adenocarcinoma tumors (8 harboring mutant KRAS and 7 with wild-type KRAS) were performed. Sequences were mapped to the human genome, and genomic features, including differentially expressed genes, alternate splicing isoforms and single nucleotide variants, were determined for tumors with and without KRAS mutation using a variety of computational methods. Network analysis was carried out on genes showing differential expression (374 genes), alternate splicing (259 genes), and SNV-related changes (65 genes) in NSCLC tumors harboring a KRAS mutation. Genes exhibiting two or more connections from the lung adenocarcinoma network were used to carry out integrated pathway analysis. The most significant signaling pathways identified through this analysis were the NFκB, ERK1/2, and AKT pathways. A 27 gene mutant KRAS-specific sub network was extracted based on gene-gene connections from the integrated network, and interrogated for druggable targets. Our results confirm previous evidence that mutant KRAS tumors exhibit activated NFκB, ERK1/2, and AKT pathways and may be preferentially sensitive to target therapeutics toward these pathways. In addition, our analysis indicates novel, previously unappreciated links between mutant KRAS and the TNFR and PPARγ signaling pathways, suggesting that targeted PPARγ antagonists and TNFR inhibitors may be useful therapeutic strategies for treatment of mutant KRAS lung tumors. Our study is the first to integrate genomic features from RNA-Seq data from NSCLC and to define a first draft genomic landscape model that is unique to tumors with oncogenic KRAS mutations.

Race and hormone receptor-positive breast cancer outcomes in a randomized chemotherapy trial

BACKGROUND

The association between black race and worse outcomes in operable breast cancer reported in previous studies has been attributed to a higher incidence of more aggressive triple-negative disease, disparities in care, and comorbidities. We evaluated associations between black race and outcomes, by tumor hormone receptor and HER2 expression, in patients who were treated with contemporary adjuvant therapy.

METHODS

The effect of black race on disease-free and overall survival was evaluated using Cox proportional hazards models adjusted for multiple covariates in a clinical trial population that was treated with anthracycline- and taxane-containing chemotherapy. Categorical variables were compared using the Fisher exact test. All P values are two-sided.

RESULTS

Of 4817 eligible patients, 405 (8.4%) were black. Compared with nonblack patients, black patients had a higher rate of triple-negative disease (31.9% vs 17.2%; P < .001) and a higher body mass index (median: 31.7 vs 27.4 kg/m(2); P < .001). Black race was statistically significantly associated with worse disease-free survival (5-year disease-free survival, black vs nonblack: 76.7% vs 84.5%; hazard ratio of recurrence or death = 1.58, 95% confidence interval = 1.19 to 2.10, P = .0015) and overall survival (5-year overall survival, black vs nonblack: 87.6% vs 91.9%; hazard ratio of death = 1.49, 95% confidence interval = 1.05 to 2.12, P = .025) in patients with hormone receptor-positive HER2-negative disease but not in patients with triple-negative or HER2-positive disease. In a model that included black race, hormone receptor-positive HER2-negative disease vs other subtypes, and their interaction, the interaction term was statistically significant for disease-free survival (P = .027) but not for overall survival (P = .086).

CONCLUSION

Factors other than disparities in care or aggressive disease contribute to increased recurrence in black women with hormone receptor-positive breast cancer.

PD05-03: Impact of Quantitative Measurement of HER2, HER3, HER4, EGFR, ER and PTEN Protein Expression on Benefit to Adjuvant Trastuzumab in Early-Stage HER2+ Breast Cancer Patients in NCCTG N9831

Background: Prediction of benefit from trastuzumab in patients (pts) with HER2+ breast cancer remains an important goal. We sought to investigate the predictive value of quantitative measurement of HER2, HER3, HER4, EGFR, ER and PTEN protein expression on the benefit of trastuzumab in the phase III HER2+ adjuvant N9831 study for pts randomized to chemotherapy alone (Arm A) or chemotherapy with sequential (Arm B) or concurrent trastuzumab (Arm C).

Methods: For each marker, we evaluated quantitative expression, relationship with demographic data, and association with disease-free survival (DFS) of pts. Freshly cut tissue microarray slides with up to three-fold redundancy per specimen from the N9831 cohort were treated identically using the AQUA (Camp, et al; Nat Med 2002, JCO 2008) method of quantitative immunofluorescence for each marker. HER2 was tested with CB11 (mouse monoclonal, Biocare, Inc.) and preliminary results were available for 698 of nearly 1400 pt specimens to be tested. The minimum value per pt was used in statistical analysis. Specimens were classified with high versus low expression based on a median value cutpoint for each marker. Median follow-up was 7.0 yrs.

Results: Quantitative HER2 was compared with centrally performed HER2 testing by IHC and FISH. Median quantitative HER2 via AQUA was 10,017 units for the HER2 IHC 3+ group (n=607) versus 1058, 831, and 970 for the HER2 IHC 2+ (n=68), 1+ (n=11), and 0 (n=11) groups, respectively. The Spearman correlation between quantitative HER2 and FISH HER2/CEP17 ratio was 0.32 (p&lt;0.001). High quantitative HER2 was associated with lower percentage of hormone receptor positivity (48% vs 59%, chi-sq p=0.003) but not associated with age, race, nodal positivity, tumor histology, grade, or size. High HER2 did not impact DFS in any arm of the study (See Table). Data for additional HER2 testing, HER3, HER4, EGFR, ER and PTEN are in process and will be ready by September, 2011.

Conclusions: Similar to results based on standard HER2 testing by IHC and FISH in N9831, quantitative HER2 did not impact benefit from adjuvant trastuzumab. Results for additional markers will be presented. Our complete quantitative results for a second epitope on HER2, HER3, HER4, ER and EGFR will be the first report of these markers in a large patient cohort in the adjuvant setting.

Disease Free Survival

P1-12-13: Comparative Pharmacokinetics (PK) of Trastuzumab Emtansine (T-DM1) in Patients Who Have or Who Have Not Received Prior Treatment for Human Epidermal Growth Factor 2 (HER2)-Positive Metastatic Breast Cancer (MBC)

Background: T-DM1, an antibody-drug conjugate composed of trastuzumab, a stable linker, and the cytotoxic agent DM1, is in development for the treatment of HER2−positive cancers. Single-agent T-DM1 3.6 mg/kg every 3 weeks (q3w) has demonstrated clinical activity in 2 phase II studies (TDM4258g and TDM4374g) in patients with pretreated HER2−positive MBC. The efficacy and safety of T-DM1 vs trastuzumab + docetaxel was investigated in patients with no prior MBC treatment in the randomized phase II study TDM4450g/BO21976. Here we report the PK of T-DM1 from that study and compare these data with those from studies that enrolled pretreated patients.

Methods: In all 3 studies, PK parameters, including maximum concentration (Cmax), area under the concentration-time curve (AUC), terminal half-life (t½), steady-state volume of distribution (Vss), and clearance (CL) were estimated by noncompartmental analysis (NCA) for serum T-DM1, serum total trastuzumab (conjugated and unconjugated), and plasma DM1. The effects of baseline trastuzumab and HER2 extracellular domain (ECD) concentration on T-DM1 exposure were explored and the relationship between T-DM1 exposure and clinical response (objective response rate [ORR] and progression-free survival [PFS]) was modeled.

Results: T-DM1 PK from evaluable patients enrolled in 3 studies are shown in Table 1. No significant correlations were observed between efficacy (as measured by ORR) and T-DM1 exposure (AUC, Cmax) after administration of T-DM1 to pretreated patients; efficacy-exposure analyses (ORR and PFS) for previously untreated patients will be presented. Patients with measurable concentrations of trastuzumab at baseline had a greater AUC during cycle 1; however, this did not impact ORR. Baseline circulating HER2 ECD concentrations also had no effect on ORR for pretreated patients. The impact of baseline trastuzumab and HER2 ECD concentrations on ORR and PFS in previously untreated patients will be presented.

PD05-04: Quantitative Measurement of Antigen Degradation in NCCTG N9831 Tissue Microarrays

Background: Unstained recuts from formalin-fixed paraffin-embedded tissues are commonly collected for cooperative group studies. There is concern among pathologists that improper storage conditions can lead to antigen degradation. In an effort to quantify this effect, we compared the expression of HER1 and HER2 on two sets of identical cohort tissue microarrays (TMAs) from the N9831 HER2+ adjuvant phase III trial (NCT00005970; www.clinicaltrials.gov); one freshly cut set (cut April 18, 2011) and a second set stored at 4 degrees for over two years (cut between Nov, 2007 and Jan, 2008).

Methods: The two sets of TMA slides containing 1580 tumor samples from the N9831 cohort were treated identically using the AQUA method of quantitative immunofluorescence. HER1 was tested with D38B1 (rabbit monoclonal, Cell Signaling Technology, Inc.) and HER2 with CB11 (mouse monoclonal, Biocare, Inc.) on tumors from 695 patients (712 specimens) in the fresh TMAs and 779 patients (800 specimens) in the old TMAs in up to three-fold redundancy per specimen.

Results: Frequency distributions of the expression of HER2 revealed bimodality in the fresh TMAs compared to an attenuated distribution of the old cases. The average score of the entire cohort was significantly lower in old TMAs compared to fresh cuts (paired t-test, p&lt;0.0001). Linear regression of the average HER2 scores from new TMAs versus the average scores from old TMAs showed a slope term of 0.52, which is statistically significantly different from the hypothetical value of 1 (p&lt;0.0001). Regressions between any two fresh slides showed slopes close to 1.0. Similar results were seen for HER1, but fewer positive cases made the changes less dramatic.

Conclusions: The storage condition of tissue slides is a critical pre-analytical variable that can dramatically lower the score of HER1 and HER2, artificially. Thus, studies done on inadequately stored slides, either whole sections or TMAs, must be interpreted with caution. Tissue collection and analysis of biomarkers for cooperative group studies should not include unstained recuts, but rather, entire blocks or large cores from tissue blocks.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD05-04.