Abstract P1-07-21: Relationship between hereditary cancer syndromes and oncotype DX recurrence score

Background

Oncotype DX Recurrence Score (RS) is used to stratify breast tumors into those likely to respond to cytotoxic chemotherapy. Women and men with hereditary cancers tend to have tumors that are chemosensitive. We hypothesize that a high RS may harbor a signal of potential hereditary risk. This analysis aims to identify whether breast cancer patients with hereditary cancer syndromes have a disproportionate amount of high RS compared to sporadic cases.

Methods

Individuals with a personal history of breast cancer who received treatment at participating research facilities and had hormone receptor positive breast cancer, Oncotype DX testing and hereditary cancer mutation testing were included. Oncotype DX RS was recorded along with the type of genetic testing and the genetic testing results. RS was categorized as low (0-17), intermediate (18-30), and high (31+). Those with deleterious mutations in any known hereditary cancer gene were considered positive. Individuals with a variant of uncertain significance (VUS) or negative genetic testing result were considered negative. Difference in distribution of tumors with low, intermediate, and high Oncotype DX results in those with hereditary breast cancers compared to those with sporadic breast cancers was determined with Chi-square.

Results

419 patients with Oncotype DX testing from two clinical sites were collected from 2013. Of those, 123 underwent genetic risk assessment. Mutations identified included the following genes: BRCA1 (1), BRCA2 (5); CHEK2 (3); BRIP1 (3); NBN (2); MSH6 (1). Of those testing positive for a deleterious mutation, the number of patients with RS results in each category were 5, 4 and 6 for low, intermediate and high, respectively. For those considered negative on hereditary cancer panel testing, the RS results were 76, 52 and 8, respectively. Of those with high RS, 43% had deleterious mutations. Chi square test was statistically significant for a difference between the RS of those with deleterious hereditary mutations versus those with sporadic cancers (p = 0.000086).

Conclusions

High RS may indicate a higher likelihood of harboring a hereditary cancer syndrome. Further investigation with larger numbers and multivariate analysis is needed to validate if a high RS serves as an independent predictor of benefit from genetic counseling and testing.

Citation Format: Toltzis S, Casasanta N, Lipinski S, Marino A, McHenry A, Denduluri N, Rodriguez P, Kaltman R. Relationship between hereditary cancer syndromes and oncotype DX recurrence score [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-07-21.

Abstract PD3-12: PIK3CA alterations and benefit with neratinib after trastuzumab-based adjuvant therapy in early-stage HER2+ breast cancer: Correlative analyses of the phase III ExteNET trial

Background: Neratinib is a pan-HER tyrosine kinase inhibitor that blocks the PI3K/Akt and MAPK signaling pathways downstream from HER2. The international, randomized, placebo-controlled phase III ExteNET trial showed that a 1-year course of neratinib after trastuzumab-based adjuvant therapy significantly improved 2-year invasive disease-free survival (iDFS) in early-stage HER2+ breast cancer (HR 0.67; 95% CI 0.50–0.91; p=0.0091) [Chan et al. Lancet Oncol 2016]. Furthermore, the effects of neratinib on iDFS were shown to be durable at 5 years' follow-up (HR 0.73; 95% CI 0.57–0.92; p=0.008) [Martin et al. ESMO 2017]. PIK3CA alterations are common in HER2+ breast cancers, and in general are associated with a worse prognosis. We sought to assess the prognostic and predictive significance of PIK3CA alterations in an exploratory substudy of the ExteNET trial.

Methods: ExteNET is an international, multi-center, randomized, double-blind, placebo-controlled phase III trial (Clinicaltrials.gov: NCT00878709). Patients received oral neratinib 240 mg/day or placebo for 1 year. Of the intent-to-treat (ITT) population (n=2840), primary formalin-fixed paraffin-embedded (FFPE) tumor specimens were available from 991 patients for PIK3CA mutation testing by RT-PCR for two hot-spot mutations in exon 9 (E542K, E545K/D) and one hot-spot mutation in exon 20 (H1047R). 702 FFPE tumor slides underwent FISH analysis for PIK3CA amplification with a ratio of ≥2.2 considered as amplified. Primary endpoint: iDFS. iDFS events were tested by 2-sided log-rank tests, and HR (95% CI) were estimated using Cox proportional-hazards models. Data cut-off: March 2017.

Results: Baseline demographics and disease characteristics between treatment arms of the correlative cohort (n=1201) were balanced. Overall, 21.2% (n=210) of primary tumors harbored one of the specified PIK3CA mutations, and 8.7% (n=61) were PIK3CA FISH-amplified. Patients with PIK3CA-altered tumors (i.e. PIK3CA mutations or FISH-amplified) had fewer iDFS events with neratinib compared with placebo (HR 0.41; 95% CI 0.17-0.90, p=0.028). The interaction test was not significant (p=0.1842). Results of the various correlative analyses within treatment arms are shown in the table.

 NeratinibPlacebo   iDFS iDFS 2-sidedPopulationnevents, nnevents, nHR (95% CI)P valueaITT142011614201630.73 (0.57–0.92)b0.008bCorrelative cohort59345608700.67 (0.45–0.96)0.0317PIK3CA-mutation positive1047106170.43 (0.17–1.01)0.056PIK3CA-mutation negative38527396420.66 (0.40-1.06)0.089PIK3CA-amplified3312840.20 (0.01-1.33)0.106PIK3CA-non-amplified31629325360.85 (0.52-1.39)0.521PIK3CA-altered1308132200.41 (0.17-0.90)0.028a. Log-rank test; b. Stratified analysis

Conclusions: One year of neratinib treatment after trastuzumab-based adjuvant therapy significantly improves iDFS after 5 years in patients with early-stage HER2+ breast cancer. From this modest-sized exploratory cohort, it appears that PIK3CA may be a biomarker for differential sensitivity to neratinib after 1 year of trastuzumab in the adjuvant setting.These exploratory results should be validated in a larger subset.

Citation Format: Chia SKL, Martin M, Holmes FA, Ejlertsen B, Delaloge S, Moy B, Iwata H, von Minckwitz G, Mansi J, Barrios CH, Gnant M, Tomašević Z, Denduluri N, Šeparović R, Kim S-B, Hugger Jakobsen E, Harvey V, Robert N, Smith II J, Harker G, Lalani AS, Zhang B, Eli LD, Buyse M, Chan A. PIK3CA alterations and benefit with neratinib after trastuzumab-based adjuvant therapy in early-stage HER2+ breast cancer: Correlative analyses of the phase III ExteNET trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD3-12.

Abstract P3-13-09: Relative dose intensity of taxane-based chemotherapy in patients with stage IV breast cancer

Background: Maintaining high relative dose intensity (RDI) has been associated with improved disease-free survival, progression-free survival, and overall survival of patients with breast cancer treated in the adjuvant setting. Neutropenia and related complications, such as febrile neutropenia, are common side effects of myelosuppressive chemotherapy that can lead to dose delays, dose reductions, and reduced RDI. Primary prophylaxis with colony-stimulating factors (CSFs) can reduce the duration and severity of neutropenia and the incidence of febrile neutropenia, thereby supporting high RDI. For patients with stage IV breast cancer, dose delays and dose reductions are frequently used to manage toxicity associated with myelosuppressive chemotherapy. However, the prevalence and impact of reduced RDI in the metastatic disease setting is poorly understood.

Objective: To estimate mean chemotherapy RDI and incidences of dose delays, dose reductions, RDI <85%, and primary CSF prophylaxis among women with stage IV breast cancer receiving first-line chemotherapy.

Methods: Using the McKesson Specialty Health/US Oncology iKnowMed™ electronic health record (HER) database, we retrospectively identified adult women with stage IV breast cancer who initiated first-line, intravenous, myelosuppressive chemotherapy from January 2007 to December 2010 in community oncology practices in the US. Patients were assigned to chemotherapy cohorts based on myelosuppressive agents received in cycle 1 and planned regimen information in the database. Standard chemotherapy regimens were defined based on NCCN breast cancer guidelines and clinical studies. Mean RDI and incidences of dose delays ≥7 days, dose reductions ≥15%, and RDI <85% in any cycle during the course of chemotherapy were evaluated relative to the standard chemotherapy regimen. Primary CSF prophylaxis was defined as first receipt of CSF during the first 5 days of chemotherapy cycle 1. Patients were followed for up to 6 months after chemotherapy initiation.

Results: This study included 1471 patients with stage IV breast cancer who received myelotoxic chemotherapy. The most common chemotherapy regimens in the metastatic setting were taxane-based, and endpoints for the three most common chemotherapy regimens (n = 307) are shown in the Table.

 Paclitaxel/ BevacizumabaAlbumin-bound PaclitaxelbPaclitaxelcN1767556Age, mean (SD) years58.2 (11.9)63.6 (12.4)61.8 (13.8)RDI, mean (SE)89.0% (1.9)89.1% (3.1)89.0% (3.2)RDI <85%37.5%41.3%26.8%Dose delays ≥7 days36.9%22.7%32.1%Dose reductions ≥15%40.9%61.3%8.9%CSF primary prophylaxis0%1.3%3.6%aPaclitaxel 80-90 mg/m2 on days 1, 8, and 15 and bevacizumab 10 mg/kg on days 1 and 15 (cycle length 28 days). Paclitaxel dose at cycle 1, day 1 was defined as the standard dose for this regimen; bAlbumin-bound paclitaxel 100 mg/m2 on days 1, 8, and 15 (cycle length 28 days); cPaclitaxel 80 mg/m2 (cycle length 7 days).

Conclusions: Chemotherapy dose delays, dose reductions, and reduced RDI were common in patients with stage IV breast cancer. The impact of RDI on progression-free and overall survival is being evaluated and will be presented.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-13-09.

Abstract P3-12-07: Dose delays, dose reductions, and relative dose intensity in early stage breast cancer patients receiving (neo)adjuvant chemotherapy in community oncology practices

Background: Neutropenic complications, such as febrile neutropenia (FN), often necessitate delays or reductions in doses of myelosuppressive chemotherapy. The resulting reduced relative dose intensity (RDI) may lead to poorer disease-free survival and overall survival among patients with early stage (stage I-IIIA) breast cancer (ESBC) (Chirivella, 2009; Wildiers, 2011).

Methods: Using the McKesson Specialty Health/US Oncology iKnowMed™ HER database, we retrospectively identified the first course of (neo)adjuvant chemotherapy received by female adult patients with ESBC who initiated treatment from 1/1/2007-3/31/2011. We then assigned patients to chemotherapy cohorts (standard regimens described in the NCCN breast cancer guidelines or in published phase 3 trials) based on chemotherapy agents received in cycle 1 and planned regimen information in the database. Only standard regimen cohorts containing ≥100 patients were included in this study. For each standard regimen cohort, we estimated the following statistics: the proportion of patients receiving colony-stimulating factor (CSF) prophylaxis in the first 5 days of cycle 1; mean RDI; and the incidences of reduced RDI (<85% over the course), dose delays (≥7 days in any cycle of the course), and dose reductions (≥15% in any cycle of the course) relative to the corresponding standard regimens. We conducted similar analyses of patient subgroups based on patient age and body surface area (BSA) at the time chemotherapy was initiated.

Results:

Study results by standard regimen cohortStandard regimen cohortNAge, mean (SD)CSF prophylaxis in cycle 1,%Mean RDI,% (SE)RDI <85%,%Dose delay ≥7 days,%Dose reduction ≥15%,%TC (4-cycle)3,41457.4 (11.0)50.789.6 (0.3)19.524.623.0TAC1,56750.6 (9.7)91.885.7 (0.5)27.136.234.8Dose-dense AC→Q2W paclitaxel1,27150.9 (10.3)89.193.5 (0.2)15.738.227.1TC (6-cycle)1,18057.3 (11.0)49.983.9 (0.6)34.440.741.7TCH1,13854.2 (11.5)55.679.4 (0.7)43.445.458.5AC→QW paclitaxel42153.9 (11.3)28.390.3 (0.5)21.957.046.6Dose-dense AC40451.9 (10.5)86.180.7 (1.1)42.344.838.4Dose-dense AC→QW paclitaxel38050.5 (10.2)92.191.1 (0.5)25.359.540.5AC39555.4 (11.1)30.482.9 (1.1)33.938.533.2AC→Q3W paclitaxel16655.7 (10.8)38.690.0 (0.7)28.350.644.0AC→docetaxel13456.0 (10.5)33.684.4 (0.9)44.854.576.1TC: docetaxel, cyclophosphamide; TAC: docetaxel, doxorubicin, cyclophosphamide; AC: doxorubicin, cyclophosphamide; TCH: docetaxel, carboplatin, trastuzumab; QW/Q2W/Q3W: every 1/2/3 week(s)

Discussion: Chemotherapy dose delays, dose reductions, and reduced RDI were common in patients with ESBC treated in community oncology practices and their frequencies were higher in older patients and in patients with BSA >2 m2. Further research should evaluate the impact of these factors on patient outcomes.

Study results by patient subgroupSubgroupNMean RDI,% (SE)RDI <85%,%Dose delay ≥7 days,%Dose reduction ≥15%,%Age <503,67788.6 (0.3)23.634.231.2Age 50-644,70487.6 (0.2)25.835.534.0Age 65-741,68784.7 (0.5)32.039.740.5Age ≥7540279.4 (1.2)42.046.549.2BSA ≤2 m28,62787.8 (0.2)25.335.833.5BSA >2 m21,84384.5 (0.4)33.237.639.8

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-12-07.

Abstract P2-11-16: Cardiac Morbidity After Adjuvant Chemotherapy (CT) for Early Breast Cancer in the Community Setting

Cardiac morbidity after exposure to CT is a known and previously described risk. Anthracycline exposure can be complicated by acute or chronic cardiac toxicity. Trastuzumab exposure is largely associated with acute and reversible cardiac morbidity.

Methods: We retrospectively queried the electronic health record (EHR) from our network of community oncology practices, iKnowMed, for patients (pts) diagnosed with Stage I-III breast cancer (BC) from 2007–2010 with at least 5 visits and follow-up (f/u) through 2012. We stratified this group by CT utilization (yes/no), regimen type, age, and characterized the incidence of cardiac disease or initiation of cardiac medication through the f/u period to determine the association of cardiac disease or treatment with CT utilization. Cardiac diseases analyzed included congestive heart failure, valvular and ischemic heart disease, arrythmias, and hypertension. Cardiac medications included beta blockers, angiotensin-converting-enzyme inhibitors, angiotensin receptor II blockers, loop and thiazide diuretics. Hazard ratios by prespecified risk parameters were then analyzed by multivariate analysis for all pts who did not have cardiac disease preceding their diagnosis of BC.

Results: We identified 20,900 pts with a median f/u of 3.2 yrs (1.4–5.4). 11,295 (54%) pts received adjuvant CT and 9,605 (46%) did not. Median age at diagnosis in the CT-treated arm and non CT-treated arm was 54 and 64 yrs, respectively (p < 0.0001). Among both the non-CT and CT-treated group, the baseline prevalence of cardiac disease was 14%. Among the CT-treated group, 3475 pts or 31% (95% CI, 30 %−32%) had or developed cardiac disease within the study period. In the non-CT group, 3790 pts or 39% (95% CI, 38%−40%) had or developed cardiac disease with the study period (p < 0.01). Receiving CT conveyed a lower risk of cardiac morbidity overall, HR 0.86 (p < 0.01). Incidence of cardiac disease was higher among pts who were in the non-CT treated arm (39%) than among the various CT-treated arms: anthracycline and trastuzumab (30%), anthracycline without trastuzumab (26%), non-anthracycline with trastuzumab (33%), and non-anthracycline without trastuzumab (34%). Incidence of cardiac disease increased proportionally over time in all age groups as expected in both cohorts.

Abstract PD10-08: Venlafaxine inhibits the CYP2D6 mediated metabolic activation of tamoxifen: Results of a prospective multicenter study: (NCT00667121)

Background: CYP2D6 is the rate limiting enzyme responsible for the metabolic activation of tamoxifen (tam) to endoxifen. Compared to CYP2D6 poor metabolizers (PM), tam-treated CYP2D6 extensive metabolizers (EM) have higher endoxifen concentrations, more vasomotor symptoms (Goetz, MP J Clin Oncol 2005), and are more likely to discontinue tam (Rae, JM 2009. Pharmacogenomics J). Additionally, higher endoxifen concentrations are associated with a stepwise increase in tam side-effects (Lorizio, W Breast Cancer Res Treat 2012). The data regarding CYP2D6 genotype and recurrence is mixed. Venlafaxine is a weak CYP2D6 inhibitor not known to alter tam pharmacokinetics (PK) and commonly recommended for tam induced hot flashes. We conducted a multicenter pharmacological study to determine whether venlafaxine altered the PK of tam and to determine the distribution of CYP2D6 genotypes in this population

Methods: Women taking tam for at least 4 weeks and for whom venlafaxine was recommended for the treatment of hot flashes were eligible. Blood samples were collected prior to and 8–16 weeks following initiation of venlafaxine for steady state tam and metabolites. Genotyping was performed for alleles associated with no (PM; *3, *4, *5,*6); reduced (intermediate, IM; *10, 17 and *41); and ultra-rapid (UM; *1×2) metabolism. Power calculations demonstrated that 17 patients with paired samples were required (two-sided alpha=0.05 t-test, 90% power) to detect a 25% change in endoxifen levels after at least 8 weeks of concurrent treatment.

Results: 30 women (median age 48.5) initiated venlafaxine. CYP2D6 genotypes were within Hardy Weinberg Equilibrium (HWE). CYP2D6 UM allele frequency (6.7%) was higher while CYP2D6 *4 (13.3%) was lower than expected compared to an unselected population (0.5 and 21% respectively; Sachse Am. J. Hum. Genet. 1997), resulting in the absence of CYP2D6 PM/PM. Mean (min/max) baseline endoxifen concentrations (8.73; 1.5–20.5 ng/ml) were correlated with CYP2D6 phenotype as follows: intermediate (EM/PM, PM/IM): 6.8 (1.5–11.2); extensive (EM/EM, EM/IM): 9.4 (1.5–20.5) and ultra-rapid (UM/EM: 11.0; 7.8–14) (r2 = 0.35 p = 0.05). In patients with paired samples (n = 20), venlafaxine resulted in a 23% decrease in endoxifen (−2.06 ng/ml; 95% CI −0.69 to −3.04; p = 0.004), but not tam, NDMT, or 4HT concentrations. Following initiation of venlafaxine, CYP2D6 genotype was no longer associated with endoxifen concentrations (r2 = 0.28 p = 0.23). For women with reduced CYP2D6 metabolism [EM/PM (n = 9) or PM/IM (n = 1)], venlafaxine lowered endoxifen concentrations (−2.98 ng/ml) to a level (5.41 ng/ml) reported to be associated with a higher risk of recurrence in adjuvant tam treated patients (Madlensky, L Clin Pharmacol Ther 2011).

Conclusions: In this study, women with tam-induced vasomotor symptoms requiring venlafaxine were comprised predominantly of CYP2D6 EM and UM metabolizers. Venlafaxine significantly decreased endoxifen concentrations. Although the optimal concentration of endoxifen is unknown, given prior data linking low endoxifen concentrations with recurrence, venlafaxine should be used with caution in tam treated patients. (Supported by R01CA133049)

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD10-08.

Abstract P4-11-04: A Structured Genetic Risk Evaluation and Testing Program in the Community Oncology Practice Increases Identification of Individuals at Risk for BRCA Mutations

Background: Genetic risk assessment is an important component of the care of the community oncology breast cancer patient. However, identification of at-risk patients is largely an ad-hoc process and practices lack a systematic approach to genetic risk evaluation. The US Oncology Network Genetic Risk Evaluation and Testing (USON GREAT) Program provides a structured approach to implementation of genetic risk evaluation, testing, and triage for appropriate intervention.

Methods: In 2009, our multi-disciplinary community oncology practice implemented the USON GREAT Program. The practice's program has a single dedicated nurse practitioner and physician lead, trained in part through a core educational curriculum and utilizing US Oncology Network-wide genetics resources (web-based MD, midlevel, and genetic counselor conferencing; discussion Portal; published guidelines and office procedures). NCCN guidelines were used to guide testing recommendations. Sequential risk evaluations were documented prospectively. We retrospectively analyzed how evaluation patterns changed over a 4 year time period. We also sought to capture descriptive characteristics of the evaluated population.

Results: Overall, between 2008 and 2011, our practice evaluated 1018 patients at potential risk for a BRCA mutation (mut), based on personal history of breast cancer under age 50; ovarian, fallopian or peritoneal cancer; known family history of malignancy; or known BRCA mutation in the family.

Abstract OT2-2-03: Dovitinib (TKI258) or placebo in combination with fulvestrant in postmenopausal, endocrine-resistant HER2–/HR+ breast cancer: a phase II study

Background: Overcoming endocrine resistance is a critical goal in the treatment of hormone receptor-positive (HR+) breast cancer. Molecular mechanisms associated with endocrine resistance include adaptive cross-talk between the estrogen receptor and the fibroblast growth factor receptor (FGFR). Up to 8% of HR+/ human epidermal growth factor receptor 2 negative (HER2–) breast cancer patients have amplification of the FGFR1 gene, which is associated with resistance to endocrine therapy. In preclinical models, resistance to endocrine therapy can be overcome via FGFR1 inhibition. Dovitinib is a potent oral inhibitor of receptor tyrosine kinases, including FGFR, vascular endothelial growth factor receptor (VEGFR), and platelet derived growth factor receptor (PDGFR), that demonstrated antitumor activity in heavily pretreated breast cancer patients with FGF-pathway amplification (FGFR1, FGFR2, or ligand FGF3; Andre et al, ASCO 2011). Dovitinib may reverse resistance to endocrine therapy related to FGF-pathway amplification and may also inhibit angiogenesis, which plays an essential role in breast cancer development. Dovitinib is studied here in combination with fulvestrant to determine if it can improve outcomes in postmenopausal patients with endocrine resistant HER2−/HR+ breast cancer.

Methods: This is a multicenter, randomized, double-blind, placebo-controlled, phase II trial that will enroll postmenopausal HER2–/HR+ locally advanced or metastatic breast cancer patients (N ≈ 150) progressing within 12 months of completion of adjuvant endocrine therapy or after ≤ 1 prior endocrine therapy in the advanced setting. Patients prospectively undergo molecular screening to enrich for FGF amplification (FGFR1, FGFR2, or FGF3 amplification by qualitative polymerase chain reaction (qPCR); 45 amplified and 30 nonamplified patients per arm). Patients are randomized 1:1 (stratified by FGF-amplification and presence of visceral disease) to receive fulvestrant intramuscularly (500 mg q4w [with an additional dose 2 weeks after the initial dose]) in combination with oral dovitinib (500 mg, 5 days on/2 days off) or placebo until disease progression, unacceptable toxicity, death or discontinuation due to any reason (eg, withdrawal). Crossover is not permitted. The primary endpoint is progression-free survival, with tumor assessments performed q8w. Secondary endpoints include overall response rate per RECIST v1.1, duration of response, overall survival, Eastern Cooperative Oncology Group performance status and patient-reported outcome scores over time, and safety. Additionally, the pharmacodynamic effect of dovitinib on FGFR-associated angiogenic pathways in tumor specimens and potential predictive biomarkers of response to dovitinib will be explored.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr OT2-2-03.

Concordance between the 21-gene recurrence score (RS) and the 70-gene profile (MP) in breast cancer (BC) patients (pts)

13

Background: Genomic assays are increasingly incorporated into treatment planning for pts with early stage BC to provide prognostic and/or predictive information. MP is a validated predictor of recurrence risk (RR) in pts without any treatment and RS is a validated predictor of RR in pts treated with 5 years of hormonal therapy (HT). Because concordance between RS and MP is largely unknown, we analyzed concordance in untreated pts that had both tests performed.

Methods: Data are from 50 early stage BC pts treated at 4 US Oncology practices and the University of California, San Francisco. We used linear regression to test whether clinical features were related to discordance, measured as part of the gamma statistic.

Results: Median age was 52.5 years, 16% (8 pts) had micro or macroscopic nodal involvement, and 66%, 30%, and 4% of pts had stage I, II, and III disease, respectively. All pts had estrogen receptor positive disease and 2 pts had HER2 overexpression by IHC or FISH. Concordance of MP and RS is shown below. Clinical features, including tumor size, grade, and HER2 were not significantly related to discordance. Gamma concordance was 0.64 (95% CI 0.28 to 0.98, p=0.0013).

Conclusions: Concordance is high, mostly due to agreement in low risk scores. Five cases are truly discordant (MP low/RS intermediate or high) based on predicted outcomes. The 11 cases with high-risk MP with low risk RS may reflect endocrine sensitivity to 5 years of HT, or true discordance. Our identification of discordance should stimulate research to further clarify biology and elucidate the drivers of different types of risk. Large studies are underway to refine risk definition and treatment recommendations.

[Table: see text]

A report of cardiac events in a phase II clinical study using trastuzumab combined with pertuzumab in HER2-positive metastatic breast cancer (MBC)

1028

Background: T and P are humanized recombinant monoclonal antibodies (MoAB) that target different epitopes of HER2 extracellular domain. P blocks HER2’s ability to heterodimerize with other HER/ErbB receptors. Methods: This Ph II trial evaluates the efficacy and safety of T with P in patients (pts) with HER2+ (FISH +) MBC who had progressive disease (PD) on T-based therapy. Eligible pts must have had = 3 T-based regimens, normal (nl) left ventricular ejection fraction (EF=55%) and without significant cardiac history. Pts received IV T (6mg/kg) and P (420 mg) every 3 weeks (wks). EKG plus echocardiogram (ECHO) or cardiac MRI and tumor response were assessed every 3 and 6 wks, respectively. Results: Eleven pts received 39 (1 to 13) cycles, 1 pt achieved a partial response (PR) and 3 pts had stable disease. A total of 68 ECHOs and 8 cardiac MRIs were performed. Left ventricular systolic dysfunction (LVSD) with nl EKG was seen in 5 pts; Grade (Gr) 1 (n = 2) (EF 50–55%), Gr 2 (n = 2) (EF 40–50%) and Gr 3 (n = 1) (EF20–40%). Gr 2–3 events were associated with global hypokinesis. Gr 3 event was associated with symptomatic CHF. All 5 pts had received 240mg/m2 cumulative dose of doxorubicin, 2 pts (Gr 2–3) received chest wall radiation, and 1 pt (Gr 1) had HTN. Two pts with Gr 1–2 LVSD had a history of reduced EF during prior T-based treatment, which reversed to nl upon stopping T. Reduced EF appeared within 1–2 cycles, which returned to nl in 3 pts within 1wk to 3 months (mo) post discontinuing T/P. One pt had persistent Gr 2 LVSD 3 mo after the initial event. The pt with Gr 3 LVSD had extensive chest wall disease and died of PD and possibly CHF 2 mo after treatment termination. Conclusions: We observed Gr 1–3 LVSD in patients with HER2+ MBC who received dual MoAB treatment directed at HER2, in which very strict cardiac surveillance guidelines were required. One of 11 pts achieved PR and 1 pt had symptomatic CHF thus far. It is unknown whether the other events would have become symptomatic if treatment had continued. Further evaluation of the efficacy of combination T with P is required to define the overall risk and benefit.

No significant financial relationships to disclose.

Cardiotoxicity after doxorubicin and AZD2171, an oral vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor, in patients (pts) with breast cancer

554

Background: AZD2171 selectively inhibits VEGFR 1,2,3. This trial examined the safety and efficacy of AZD2171 with anthracycline-containing therapy. Methods: Pts with previously untreated Stage IIB and III breast cancer received neoadjuvant AZD2171 (30mg) alone for one cycle (1 week) followed by daily AZD2171 and TAC chemotherapy with docetaxel (T), doxorubicin 50 mg/m2 (A) cyclophosphamide (C) for 6 cycles (Cy) every 3 weeks. Pts underwent breast surgery after completing neoadjuvant therapy. Eligible pts had left ventricular ejection fraction (EF) = 50%, and no uncontrolled HTN or cardiac history. Pts underwent electrocardiogram (EKG), and troponin first day (D) of every Cy and 24 hours after TAC as well as serial echocardiograms (echo). Cardiac stress MRI with dipyridamole was performed when pts had decreases in EF by echo. Results: Two pts received 2 Cy of AZD2171 alone, 9 Cy with TAC and AZD2171, and 1 Cy with TAC alone. Pt 1 and Pt 2 developed hypertension requiring medical therapy Cy4, D1 (148/97 mm Hg) and Cy2, D2 (169/93 mm Hg) respectively. Pt 1 had asymptomatic decrease in EF from 65% to 40% (grade 2) with global hypokinesis pre-Cy5 by echo. Troponin and EKG were negative for acute ischemia. Cardiac stress MRI was normal and EF returned to 60% within 48 hours. The pt continued therapy and pre-Cy7 EF was 51% by echo. Cumulative A dose received was 250mg/m2 pre-Cy7. AZD2171 was held while Cy7 TAC was continued. EF was 57% by echo 1 month after Cy7 TAC. Pt 2 had asymptomatic decrease in EF from 65% to 50% pre-Cy4 by echo with mild global hypokinesis. Troponin and EKG were negative for acute ischemia. Cardiac stress MRI showed EF of 56% with no ischemia. She continued AZD2171 and TAC. Pre-Cy5 EF was 35–40% (grade 3) with global hypokinesis. Troponin and EKG were negative. Cumulative dose of A received was 150mg/m2. AZD2171 and A were stopped; T and C were continued. EF normalized to 55% by cardiac stress MRI and echo within 21 days. Conclusion: Due to the systolic dysfunction that occurred with concurrent AZD2171 and doxorubicin administration, the study is closed. Future trials should administer AZD2171 and anthracyclines sequentially with stringent monitoring of blood pressure and ejection fraction.

No significant financial relationships to disclose.

Effect of bevacizumab (BV) and chemotherapy (CT) on serum levels of vascular endothelial growth factor receptor-2 (sVEGFR-2) in patients with inflammatory and locally advanced breast cancer

13003

Background: VEGFR-2 is a principal mediator of angiogenesis. The effects on sVEGFR-2 after anti-angiogenesis therapy are unknown. Methods: Twenty-one patients (pts) with breast cancer underwent neoadjuvant treatment with BV for 1 cycle (C1) followed by 6 cycles of BV, CT and filgrastim. Blood was collected at baseline (BL), post-cycles 1, 4 and 7. Objectives were to correlate sVEGFR-2 changes after treatment with response, assess wound healing complications, and evaluate for tumor VEGFR-2 mutations. sVEGFR-2 levels were measured by ELISA. Exons 17–26 were sequenced on tissue samples from 20 pts at BL and post C1 to evaluate for VEGFR-2 mutations. Statistical testing is non-parametric. All p-values are two-tailed, with a p < 0.01 interpreted as a statistically significant difference. Results: Thirteen pts had a partial response (PR), 1 unconfirmed PR, 5 stable disease (SD), and 2 progressive disease (PD). Median sVEGFR-2 levels increased by 16% from BL to post C1 (p = 0.0003) and decreased by 19% post C1 to post C4 (p = 0.048). sVEGFR-2 levels were not associated with clinical response. sVEGFR-2 levels at BL did not correlate with other BL parameters: Ki67, microvessel density, VEGF-A, pVEGFR-2, VEGFR-2 or TUNEL (apoptosis). A moderate-weak correlation was seen between post C1 levels of sVEGFR-2 and pVEGFR-2 (r = 0.43). A moderate inverse correlation was seen in the relative difference of sVEGFR-2 and TUNEL from BL to post C1 (r = −0.59). Comparing pts with (n = 5) and without (n = 16) wound healing problems, median sVEGFR-2 levels were 11322 ng/ml and 7524 ng/ml at BL (p = 0.019), 13928 ng/ml and 10148 ng/ml post C1 (p = 0.029), and 10965 ng/ml and 7932 ng/ml post C4 (p = 0.042). In 40 samples where tumor VEGFR-2 sequencing was obtained, no mutations were seen compared to the reference sequence. Conclusion: sVEGFR-2 levels rose significantly following BV alone but were not associated with response. There is a suggestion that sVEGFR-2 may correlate with activated VEGFR2 and a decrease in apoptosis. sVEGFR-2 levels were higher in pts with wound healing problems and may predict pts at higher risk of this complication. There were no mutations of VEGFR2.

[Table: see text]

Phase II clinical trial of ixabepilone in metastatic breast cancer (MBC) patients previously untreated with taxanes

651

Background: Ixabepilone, an epothilone B analog, stabilizes microtubules by binding to tubulin. The response rate (RR) in taxane-pretreated patients at our institution was 22%. Methods: Patients (pts) were eligible if they had MBC previously untreated with taxanes and measurable disease by RECIST criteria. Ixabepilone was given at 6mg/m2/d intravenously days 1–5 every 3 weeks until unacceptable toxicity or disease progression. Primary objectives included RR and toxicity. Pts underwent pre and/or post treatment tumor biopsies for correlative studies. Acetylated α-tubulin, Tau-1, and p53 were stained with anti-acetylated α-tubulin, anti-Tau-1, and anti-p53 antibodies in samples from 13 pts. Staining was scored quantitatively using the Automated Cellular Imaging System. Results: Twenty-three pts received 197 cycles (C). Median of 7C (range 2–22) per pt were administered. Median age was 55 (range 22–79). Seven pts received 1 prior metastatic chemotherapy regimen. Ten of 23 or 43% (exact 95% confidence interval: 23.2% to 65.5%) pts had partial responses (PR), 9 (39%) stable disease (SD) (2 unconfirmed PRs), and 4 (17%) progressive disease (PD). Median time to progression was 5.3 months; median duration of response was 5.4 months from date of best response. Four pts required dose reductions for neutropenia, neuropathy or fatigue. Grade 3/4 toxicities included neutropenia (22%), fatigue (13%), anorexia (9%), infection without neutropenia (9%), motor neuropathy (4%), and muscle weakness (4%). No grade 3/4 sensory neuropathy was seen, but 35% and 13% of pts had grades 1 and 2 neuropathy respectively. Median acetylated α-tubulin at baseline was 0.2 in responders and 17.6 in non-responders (p=0.069). There were no differences in response according to Tau-1 or p53 expression at baseline. Conclusion: Ixabepilone is an effective treatment for MBC with a 43% RR in 23 pts previously untreated with taxanes. There was minimal hematologic toxicity and no grade 3 sensory neuropathy. The use of baseline level of acetylated α-tubulin to predict response may warrant further study.

No significant financial relationships to disclose.