E. Perez

Results of Chemotherapy Alone, with Sequential or Concurrent Addition of 52 Weeks of Trastuzumab in the NCCTG N9831 HER2-Positive Adjuvant Breast Cancer Trial.

Background: N9831 is the only randomized phase III trial comparing safety and efficacy of the addition of trastuzumab (H) to doxorubicin and cyclophosphamide then paclitaxel (Arm A: AC→T) either following (Arm B: AC→T→H) or starting concurrently with paclitaxel (Arm C: AC→T+H→H) for women with resected Stage I-III invasive HER2+ breast cancer. The 3 yr cumulative incidence of NYHA class III or IV congestive heart failure or sudden cardiac death was previously reported: 3.3% in Arm C, 2.8% in Arm B (Perez EA, et al. JCO 2008). The comparison of AC→T to AC→T+H→H was reported in a joint analysis of N9831 and NSABP B-31 in 2005 and updated in 2007, demonstrating a 52% reduction in risk of a disease event (Romond E et al., NEJM 2005; Perez EA, et al. ASCO 2007).Materials and Methods: Primary endpoint is disease-free survival (DFS). At the second planned interim analysis of Arm A vs. Arm B, the O’Brien-Fleming boundary (OFB) was crossed. NCCTG Independent Data Safety Monitoring Committee approved the release of these data as well as the data pertaining to Arm B vs. Arm C due to slow pace of events [expected 647 events in 4 yr follow-up period (f/u) vs. actual 334 events in 4.5 yr f/u]. Shortly thereafter, there were sufficient events to perform the first planned interim analysis of B vs. C. We present the results of each of these pairwise comparisons taking into account the potential for crossover to Arm C after the release of the joint analysis findings in 2005.Results: From 5/2000 to 4/2005, 2448 eligible women were enrolled for the Arm A (n=1087) vs. Arm B (n=1097) comparison. Median f/u is 5.5 yrs. with 386 events. The addition of trastuzumab sequentially to AC→T significantly improved DFS, univariately [HR(Arm B/Arm A)=0.70, 95% CI: 57-86%, logrank p=0.0005] and after adjusting for age, tumor size, number of positive nodes, and ER [PPH: HR adj =0.67 (95% CI: 0.55-0.82)]. 5 yr DFS was increased from 72% with AC→T to 80% with AC→T →H.From 5/2000 to 4/2005, 1903 eligible women were enrolled for the Arm B (n=954) vs. Arm C (n=949) comparison. Median f/u is 5.3 yrs. with 312 events. The log-rank p-value testing whether DFS differs with respect to starting time of trastuzumab was 0.019. [Not crossing pre-specified OFB for statistical significance]. After adjusting for tumor size, number of positive nodes, and ER, HR adj (Arm C/Arm B)=0.75 (95% CI: 0.60-0.94)]. 5 yr DFS was increased from 80% with AC→T →H to 84% for AC→T+H →H.Conclusions: DFS is significantly improved with the addition of 52 weeks of H (sequentially or concurrently) to AC→ T. There is a statistically significant 33% reduction in the risk of an event with the sequential addition of H following AC→T. There is a strong trend for a 25% reduction in the risk of an event with starting H concurrently with T relative to sequentially after T. Therefore, based on a positive risk/benefit ratio, we recommend that trastuzumab be incorporated in a concurrent fashion with T chemotherapy.Acknowledgements: NIH CA25224, Breast Cancer Research Foundation, Genentech. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 80. NOTE: This abstract was accepted for presentation at the Symposium after the Abstract Book went to press.

The Effect of Zoledronic Acid on Aromatase Inhibitor-Associated Bone Loss in Postmenopausal Women with Early Breast Cancer Receiving Adjuvant Letrozole: The Z-FAST Study 5-Year Final Follow-Up.

Background: Aromatase inhibitor (AI) therapy effectively increases disease-free survival in postmenopausal women (PMW) with ER+ and/or PR+ breast cancer (BCa). However, the use of AIs results in nearly complete ablation of estrogen production which can lead to accelerated bone loss and increased fracture risk. The Z-FAST study evaluated the efficacy and safety of zoledronic acid (ZOL) in preventing AI associated bone loss in PMW with early breast cancer (EBC) who received adjuvant letrozole (LET).Material and Methods: 602 PMW with stage I-IIIa ER+ and/or PR+ BCa starting LET (2.5 mg qd x 5 yrs) were randomized (1:1) to upfront ZOL (4 mg IV q 6 mos) vs delayed ZOL. The delayed arm (D) received ZOL when either the post-baseline T-score decreased to -1), and no U pts as compared to 4.9%(4) D pts became severely osteopenic (T Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4083.

RIBBON-2: A Randomized, Double-Blind, Placebo-Controlled, Phase III Trial Evaluating the Efficacy and Safety of Bevacizumab In Combination with Chemotherapy for Second-Line Treatment of HER2-Negative Metastatic Breast Cancer.

Background: Three prior Phase III trials (E2100, AVADO, and RIBBON-1) established the clinical benefit of adding bevacizumab (BV) to various chemotherapies (chemos) as first-line treatment for metastatic breast cancer (MBC). A previous Phase III study (AVF2119g) in patients with predominantly heavily pre-treated MBC, in which BV was added to capecitabine (Cape), resulted in a significant increase in objective response rate (ORR), but did not meet the primary endpoint for progression-free survival (PFS). The current study, RIBBON-2, was designed to evaluate the efficacy and safety of the addition of BV to chemotherapies used as second-line treatment for MBC.Methods: Patients were randomized in a 2:1 ratio to chemo+BV or chemo+placebo (PL). Key eligibility criteria included one prior cytotoxic treatment for MBC, ECOG performance status of 0 to 1, and HER2-negative or unknown status. Prior to randomization, investigators chose one of the following chemo agents: taxane (T; paclitaxel 90 mg/m2/wk for 3 of the 4 weeks; paclitaxel 175 mg/m2, nab-paclitaxel 260 mg/m2, docetaxel 75–100 mg/m2, all given q3wk), gemcitabine (G; 1250 mg/m2 on Days 1 and 8 q3wk), Cape (2000 mg/m2 Days 1–14 q3wk), or vinorelbine (V; 30 mg/m2/wk). BV or PL was administered at 10 mg/kg q2wk or 15 mg/kg q3wk, depending on the chemo regimen. The primary endpoint of the study was investigator-assessed PFS pooled across the chemo cohorts. Key secondary endpoints included overall survival (OS), PFS within individual chemo cohorts, ORR, and safety.Results: 684 patients (T, 304; G, 160; Cape, 144; and V, 76) at 211 sites in 19 countries were randomized between February 2006 and June 2008. Overall, the two study arms were balanced for patient characteristics at baseline. The study met its primary endpoint of PFS pooled across chemo cohorts and also demonstrated a 10% increase in ORR when BV was added to chemo. At the interim analysis for OS, the median durations were 18 mo for chemo+BV and 16.4 mo for chemo+PL (see table).Across all chemo cohorts the incidence of BV-related AEs was consistent with data from previous studies. Hypertension was the only BV-related AE consistently increased in the chemo+BV arm across all chemo cohorts.Conclusions: The addition of BV to chemotherapies used for second-line treatment of MBC led to a significant improvement in PFS. The AE profile of BV in the overall study population and across the chemotherapy cohorts was consistent with that previously observed. Additional analyses, including PFS for the individual chemo cohorts, will be presented. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 42.

Outcomes of Women Who Were Premenopausal at Diagnosis of Early Stage Breast Cancer in the NCIC CTG MA17 Trial.

Background: MA17 showed that adjuvant letrozole after 5 years of tamoxifen markedly reduced the risk of recurrence in women with ER+ early stage breast cancer and improved overall survival in women presenting with node +ve disease. Most trials of early adjuvant aromatase inhibitor therapy required women to be postmenopausal at diagnosis to be eligible. We report here on a subset of women in the MA17 trial who were premenopausal at initial diagnosis and in whom subsequent menopause, prior to randomization, may have influenced their outcome on extended adjuvant letrozole.Methods: Women randomized to MA17 were divided into 2 groups: 1) pre-menopausal ( Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 13.

Tamoxifen pharmacogenetics of CYP2D6, CYP2C19, and SULT1A1: long term follow-up of the North Central Cancer Treatment Group 89-30-52 adjuvant trial.

CTRC-AACR San Antonio Breast Cancer Symposium: 2008 Abstracts Abstract #6037 Background: Tamoxifen (Tam) is biotransformed to the potent antiestrogen, endoxifen, by the CYP2D6 enzyme. We previously demonstrated that patients (pts) receiving adjuvant TAM with impaired CYP2D6 metabolism due to CYP2D6 (*4) and/or concurrent administration of a CYP2D6 inhibitor had a higher risk of recurrence. Other studies suggest CYP2C19*17 (Schroth JCO 2007) and SULT1A1 *2 (Nowell JNCI 2002) may be associated with treatment outcome. With extended follow-up, we sought to evaluate the importance of comprehensive CYP2D6 genotyping as well as the potential association between CYP2C19*17 and SULT1A1 copy number with clinical outcome in pts randomized to TAM in NCCTG 89-30-52. Methods: Using DNA derived from paraffin embedded sections, CYP2D6 and SULT1A1 genotype were determined using quantitative multiplex PCR and CYP2C19 by sequencing. Pts administered the following CYP2D6 inhibitors (fluoxetine, paroxetine, sertraline, cimetidine, amiodarone, doxepin, ticlopidine and haloperidol) were considered as intermediate (IM) or poor metabolizers (PM) based on the potency of CYP2D6 inhibition. CYP2D6 phenotype was defined as follows: extensive metabolizers (EM) were pts not administered an inhibitor who did not carry a null allele (*3, *4, *6) and who were not homozygous for an IM allele (*10, *17, *41). CYP2D6 IM were either heterozygous for a null allele or homozygous for an IM allele but not administered an inhibitor or CYP2D6 EM administered a weak inhibitor. PM were pts homozygous for a null allele, or any patient administered a potent inhibitor. The association between genotype or CYP2D6 phenotype and clinical outcome was determined using the log-rank test. Multivariate Cox modeling was performed using traditional prognostic factors . Results : The median follow-up of living pts is now 14.5 years. Of 256 pts. randomized to TAM, genotype was determined for CYP2D6 (n=210), CYP2C19*17 (n=170), and SULT1A1 (n=169) with the following allele frequencies: CYP2D6 *3 (.02), *4(.20), *6 (.01), *10 (.03), *17 (.00), *41(.08), and CYP2C19*17 (.22). The frequency of SULT1A1 copy number alleles (CNA) was 1 (4%), 2 (67%), 3 (20%), and 4+ (9%). 14/227 patients (6%) were administered an inhibitor. A multivariate analysis accounting for nodal status and tumor size demonstrated that compared to CYP2D6 EM, CYP2D6 PM had significantly shorter time to recurrence (TTR) (HR 4.0, p=0.001) and DFS (HR 2.0, p=0.02) and CYP2D6 IM tended to have shorter TTR (HR 1.8, p=0.08) and DFS (HR 1.4, p=0.10). DFS did not differ by SULT1A1 copy number (p=0.62) or CYP2C19 *17 (p=0.47) Conclusion: Long term follow-up of pts in NCCTG 89-30-52 confirms the importance of CYP2D6 metabolism and further demonstrates the importance of comprehensive genotyping and phenotyping with CYP2D6 inhibitors. We could not identify an association between CYP2C19*17 or SULT1A1 copy number with recurrence but further evaluation is needed in larger cohorts. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6037.

c-MYC amplification and correlation with patient outcome in early stage HER2+ breast cancer from the NCCTG adjuvant intergroup trial N9831.

CTRC-AACR San Antonio Breast Cancer Symposium: 2008 Abstracts Abstract #56 Background: Recent findings from NSABP B-31 suggested that breast cancer (BC) patients (pts) with c-MYC (MYC)/HER2 co-amplification in their primary tumors may benefit more in terms of disease-free survival (DFS) from adjuvant trastuzumab (n=471; p<0.0001, HR 0.24; 13 vs. 51 events) than those pts with only HER2 amplification in their primary tumors (n=1078, p=0.007, HR 0.63; 55 vs. 82 events). Purpose: The overall objective of this analysis is to determine the association between MYC/HER2 co-amplification and outcome of pts randomized to receive chemotherapy alone (Arm A) or chemotherapy with concurrent trastuzumab (Arm C) on N9831. Patients/Methods: This analysis included 868 pts from the HER2+ NCCTG N9831 Intergroup adjuvant trastuzumab phase III clinical trial on Arms A or C. Fluorescent in situ hybridization (FISH) was performed at a central laboratory, Mayo Clinic Clinical Cytogenetics Laboratory, using dual probe mixtures for HER2 (17q11.2-12/centromere 17) and for MYC (8q24/centromere 8). The HER2 amplification status in whole tissue sections was evaluated to determine eligibility of pts for N9831. Tissue microarrays containing three cores from each patients tumor were analyzed for MYC amplification status. The gene and centromere copy number as well as the distribution of the signals for each marker were determined in sixty non-overlapping interphase nuclei. Results: Of 273 pts with completed FISH analyses, 34 (12%) pts had MYC amplification. The rate of MYC amplification was similar across arms (18/135 [13%] vs. 16/138 [12%]; ChiS p=0.66). Co-amplification of MYC/HER2 was observed in 32 (12%) pts with similar co-amplification rates across arms (17/135 [13%] vs. 15/138 [11%]; ChiS p=0.66). Based on preliminary analyses, MYC amplification and MYC/HER2 co-amplification do not appear to be associated with race, menopausal status, hormone receptor status, nodal status, tumor histology, tumor grade, or tumor size (all ChiS p>0.05); however, MYC amplified pts were significantly younger than MYC non-amplified pts (mean 46.4 vs. 51.0, t-test p=0.02) and MYC/HER2 co-amplified pts were significantly younger than MYC/HER2 non-co-amplified pts (mean 45.9 vs. 51.0, t-test p=0.01). Conclusions: In our initial analyses of 239 pts, we observed a lower frequency of MYC/HER2 co-amplification than the previously reported 30% for NSABP B-31. Complete FISH analyses of 868 pts in N9831 and association with DFS will be presented. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 56.

Clinical Benefit Rate and Time to Response in RIBBON-1, a Randomized, Double-Blind, Phase III Trial of Chemotherapy with or without Bevacizumab (B) for the First-Line Treatment of HER2-Negative Locally Recurrent or Metastatic Breast Cancer (MBC).

BackgroundRIBBON-1, a Phase III, multicenter, randomized, placebo-controlled trial in patients with previously untreated MBC was designed to evaluate the efficacy and safety of adding bevacizumab (B) to chemotherapy regimens including capecitabine (Cape; n=615); a taxane (T; n=307), or an anthracycline (Anth; n=315) compared with chemotherapy alone. Pre-specified analyses of progression-free survival PFS) in the Cape and pooled T/Anth cohorts, the primary endpoints of the study were increased upon addition of B. In the Cape cohort, median PFS increased from 5.7 to 8.6 mo (HR=0.69, p-value=0.0002) and in the T/Anth cohort, it increased from 8.0 to 9.2 mo (HR=0.64; p-value Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6084.

Abstract PD10-04: Predictive genomic markers to chemotherapy and adjuvant trastuzumab via whole genome expression DASL profiling in the N9831 adjuvant study

Background: Adding adjuvant trastuzumab to chemotherapy for patients (pts) with resected HER2+ breast cancer (BC) improves disease free and overall survival (Perez EA, et al. J Clin Oncol 2011). Understanding which pts are most likely to benefit from these therapies is a goal of our team. Methods: Baseline 1639 annotated tumor specimens from pts enrolled in the phase III N9831 adjuvant trastuzumab trial (NCT00005970) were processed via the >29,000 gene probe DASL technology (Illumina) to identify genomic predictors of pt outcome to Arm A chemotherapy or Arm C chemotherapy plus concurrent trastuzumab. Samples were spotted in 96 well plates, with appropriate replicates. Extensive quality control and internal validation were performed. The association of each gene with recurrence-free survival (RFS) was determined for each treatment arm separately using CoxPH models adjusted for clinical and tumor risk factors. A p Results: PRPF4B, EWSR1, BMI1, CNNM1, FOXO4, CLIP2, MCCC1, CHRM2 were found to be significantly associated with RFS for Arm A and AAK1, DAZAP2, TP53INP1, MACF1 and ADHFE1 were associated with RFS for Arm C. The most significant pathway associated with RFS in Arm A was the KEGG hypertrophic cardiomyopathy pathway and for Arm C, the BioCarta pertussis toxin-insensitive CCR5 signaling in macrophage pathway. Conclusions: We have identified 8 genes associated with RFS for pts treated with adjuvant chemotherapy, and 5 genes associated with RFS for pts treated with concurrent trastuzumab and chemotherapy in pts with HER2 early stage BC. In addition, geneset analysis identified BioCarta and Kegg pathways associated with RFS for each arm. Validation in an independent cohort is expected to be completed by the end of 2012. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD10-04.

Paclitaxel-Related Peripheral Neuropathy Associated with Improved Outcome of Patients with Early Stage HER2+ Breast Cancer Who Did Not Receive Trastuzumab in the N9831 Clinical Trial.

Background: Microtubules are crucial for spindle formation during mitosis and for cellular proliferation. The antineoplastic effect of paclitaxel is mainly related to its ability to bind the beta subunit of tubulin, thus preventing tubulin chain depolarization and inducing apoptosis. Tubulins are expressed in human peripheral nerves and the binding of paclitaxel to tubulin may lead to neuropathy. Peripheral neuropathy is a common dose limiting toxicity of paclitaxel. We hypothesized that the occurrence of peripheral neuropathy may correlate with outcome (disease-free survival; DFS). Methods: This analysis sought to describe incidence of peripheral neuropathy following paclitaxel and its association to outcome (DFS) in patients who received paclitaxel (weekly x 12) in the adjuvant HER2+ intergroup trial N9831. Only eligible pts who initiated paclitaxel and did not have peripheral neuropathy at initiation of paclitaxel that were randomized to arms A (955 pts; chemotherapy alone) and C (889 pts; chemotherapy plus concurrent trastuzumab) of N9831 were included. Cox regression analysis stratified by ER/PR status and nodal status was used to compare DFS within arm between patients with and without peripheral neuropathy. Results: Out of 1844 eligible pts, 379 developed neuropathy (20.5%). For pts in arm A, those who developed neuropathy had better DFS than pts who did not (3 yr DFS: 86.2% vs 81.8%; HR 0.65; p=0.01), despite lower doses of paclitaxel in the pts with neuropathy. Grade of neuropathy did not appear to impact DFS. No statistical difference was noted for pts treated in the trastuzumab-containing arm (3 yr DFS: 92.8% vs 91.1% for pts with neuropathy vs not; HR 0.79; p=0.34). There were no differences in paclitaxel dose intensity between arms A and C. Conclusion: Patients with early stage HER2+ breast cancer who received adjuvant paclitaxel-containing chemotherapy in arm A and developed peripheral neuropathy had a better DFS than pts who did not develop neuropathy. This effect was possibly abrogated by the use of trastuzumab in Arm C. This side effect may represent effective bindings of paclitaxel to the target tubulin, lack of point mutations in tubulin at the paclitaxel binding site and/or lack of selective overexpression of β-III tubulin. This is a hypothesis generating study and additional analysis needs to be conducted from other large taxane-based trials.Partial support from Genentech and the Breast Cancer Research Foundation Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2100.

Do the ASCO/CAP 2007 HER2 Testing Guidelines Improve Prediction of Benefit to Adjuvant Trastuzumab?: Data from North Central Cancer Treatment Group N9831 Adjuvant Trial.

Background: In 2007, the American Society of Clinical Oncology and College of American Pathologists (ASCO/CAP) recommended new guidelines to define HER2 positivity by immunohistochemistry (3+ IHC: uniform intense membrane staining of >30% of invasive tumor cells) or fluorescent in situ hybridization (FISH+: HER2/CEP17 ratio >2.2). The original criteria used for enrollment in the pivotal N9831 trial conducted from 2000-2005 were IHC>10% (3+) or FISH ≥2.0.Purpose: To investigate the impact of the ASCO/CAP guidelines on patient (pt) eligibility and disease free survival (DFS) compared to the originally used FDA-approved definitions.Patients/Methods: This analysis included 2268 patients from the HER2+ N9831 adjuvant trastuzumab phase III trial. IHC was centrally performed at the Mayo Clinic using the DAKO HercepTest™ and was re-analyzed to determine the percent of tumor cells with 0, 1+, 2+, and 3+ staining intensities. DFS was compared between pts randomized to standard chemotherapy +/- concurrent trastuzumab (Arms A and C of the trial) within IHC/FISH subgroups using Cox proportional hazards regression stratified by hormone receptor and nodal status.Results: Based on 2268 pts, 83 pts (3.7%) were 3+ by FDA-approved guidelines but not 3+ by the ASCO/CAP guidelines. Among these pts, 77% (64/83) were FISH amplified centrally by ASCO/CAP guidelines. Only 1.5% (34/2268) of pts eligible under FDA-approved definitions from N9831 in this sample set would not meet the ASCO/CAP guidelines. In 1441 patients randomized to standard chemotherapy +/- concurrent trastuzumab, the exploratory DFS hazard ratio (HR) associated with trastuzumab in IHC/FISH subgroups were as follows: ASCO/CAP HER2+ HR=0.59 (95% CI: 0.47-0.75; p Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 701.