How we treat HER2-positive brain metastases

Overexpression of the human epidermal growth factor 2 (HER2)/neu glycoprotein receptor in breast cancer is associated with increased risk of brain metastases, especially in patients with advanced disease. Improvements in the treatment of HER2-positive breast cancer has led to prolonged survival of patients with advanced disease, but the prevention and management of central nervous system metastases still poses unique clinical challenges given the associated morbidity and mortality of this site of disease. HER2-positive brain metastases are treated with surgery, radiation (stereotactic radiosurgery or whole brain radiotherapy), and systemic therapies, and are best managed by an experienced multidisciplinary team. The present article aims to provide an overview to our approach to treatment of HER2-positive brain metastases, including a review of agents with central nervous system activity, as well as management suggestions for several nuanced clinical scenarios.

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HER2-positive subtype of breast cancer is a risk factor for development of intracranial metastases in advanced disease.

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Treatment paradigms for HER2-positive brain metastases include both local and systemic approaches.

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Several anti-HER2-directed therapies that show intracranial activity should be used for systemic treatment of brain metastases.

Reversion and non-reversion mechanisms of resistance to PARP inhibitor or platinum chemotherapy in BRCA1/2-mutant metastatic breast cancer

BACKGROUND

Little is known about mechanisms of resistance to poly(adenosine diphosphate-ribose) polymerase inhibitors (PARPi) and platinum chemotherapy in patients with metastatic breast cancer and BRCA1/2 mutations. Further investigation of resistance in clinical cohorts may point to strategies to prevent or overcome treatment failure.

PATIENTS AND METHODS

We obtained tumor biopsies from metastatic breast cancer patients with BRCA1/2 deficiency before and after acquired resistance to PARPi or platinum chemotherapy. Whole exome sequencing was carried out on each tumor, germline DNA, and circulating tumor DNA. Tumors underwent RNA sequencing, and immunohistochemical staining for RAD51 foci on tumor sections was carried out for functional assessment of intact homologous recombination (HR).

RESULTS

Pre- and post-resistance tumor samples were sequenced from eight patients (four with BRCA1 and four with BRCA2 mutation; four treated with PARPi and four with platinum). Following disease progression on DNA-damaging therapy, four patients (50%) acquired at least one somatic reversion alteration likely to result in functional BRCA1/2 protein detected by tumor or circulating tumor DNA sequencing. Two patients with germline BRCA1 deficiency acquired genomic alterations anticipated to restore HR through increased DNA end resection: loss of TP53BP1 in one patient and amplification of MRE11A in another. RAD51 foci were acquired post-resistance in all patients with genomic reversion, consistent with reconstitution of HR. All patients whose tumors demonstrated RAD51 foci post-resistance were intrinsically resistant to subsequent lines of DNA-damaging therapy.

CONCLUSIONS

Genomic reversion in BRCA1/2 was the most commonly observed mechanism of resistance, occurring in four of eight patients. Novel sequence alterations leading to increased DNA end resection were seen in two patients, and may be targetable for therapeutic benefit. The presence of RAD51 foci by immunohistochemistry was consistent with BRCA1/2 protein functional status from genomic data and predicted response to later DNA-damaging therapy, supporting RAD51 focus formation as a clinically useful biomarker.

Abstract PD9-01: Genomic alterations associated with loss of HR expression in metastatic breast cancer

Background: Discordance in hormone receptor (HR) status between primary (p) tumors and metastatic (m) recurrences has been widely described. Loss of estrogen and progesterone receptor expression occurs in ˜12% of asynchronous recurrences, leading to triple-negative (TN) status in the metastasis. Genomic mechanisms driving HR loss and its prognostic and therapeutic implications have not been fully elucidated.

Methods: Targeted NGS (Oncopanel, OP) at Dana-Farber Cancer Institute using multiplexed copy number variation and mutation (mut) detection across the full coding regions of 300 genes and selected intronic regions of 35 genes was prospectively performed on either archival primary or metastatic samples collected in patients (pts) with metastatic breast cancer (MBC). Receptor status at initial diagnosis and recurrence were reviewed using a 1% cutoff to define HR-positivity and excluding HER2+ cases. Fisher´s exact test was used to compare frequency of alterations. Tumor mut burden (TMB) was computed normalizing the sum of reported exon mut in each pt by the exonic-bait-set size of the panel.

Results: Between 8/2013-9/2016, 929 pts with MBC underwent OP testing. Of 517 pts diagnosed with primary HR+/HER2- breast cancer, at time of recurrence 388 remained HR+/HER2- (pHR+/mHR+), 39 switched to HR-/HER2- (pHR+/mTN, of which 23 (59%) had initial HR expression >10%), 10 switched to HER2+ and 80 had unknown metastatic receptor status. Comparison between primary samples in pHR+/mHR+ (n=245) and pHR+/mTN (n=24) showed that pHR+/mTN was significantly more likely to harbor mut in TP53, STK11 and MSH6, amplifications (amp) in CCNE1 and FGFR2, and less likely to have PIK3CA mut or CCND1 amp. Median TMB in primary pHR+/mHR+ was 6.05 mut/Mb (0-37.5) and 5.68 mut/Mb (1.2-10.9) in pHR+/mTN (p=0.45). Metastatic samples in pHR+/mTN (n=15) were enriched in ARID1A, CRTC2 and CDH1 mut compared to metastases (n=40) in pts who remained TN (pTN/mTN). Deletions in CDKN2A/2B and RB1, and mut in TP53, NOTCH2 and ERCC2 were more prevalent in recurrent tumors of pHR+/mTN than pHR+/mHR+. In metastases, TMB was higher in pHR+/mTN than pTN/mTN or pHR+/mHR+ (10.9 vs. 7.0 vs. 7.3 mut/Mb, respectively; p=0.002). Median OS from initial diagnosis was 9.4 yrs in pHR+/mTN, less than pHR+/mHR+ (15.9 yrs; p=0.009) and greater than pTN/mTN (4.3 yrs; p=0.008). Median OS from MBC diagnosis was 1.8 yrs in pHR+/mTN, less than pHR+/mHR+ (6.4 yrs; p=0.001) but not significantly different than pTN/mTN (1.5 yrs, p=0.3).

 pHR+/mHR+ (n=245)pHR+/mTN (n=24)p value NFreq (%)NFreq (%) MutTP536325.72083.3<0.00001PIK3CA9438.4000GATA33514.3000.053STK1152.0312.50.026MSH641.6312.50.017AmpFGFR20028.30.008CCNE10028.30.008CCND14418.0000.018

Conclusion: Targeted NGS shows that alterations in DNA damage and cell-cycle regulation pathways in primary HR+ tumors are associated with HR loss in the metastatic setting. Primary tumors that lose HR appear more similar to basal-like than luminal tumors, despite >10% baseline HR expression in most pts, and once metastatic, survival is comparable to pTN/mTN. Metastases with HR loss have higher TMB than those that remain HR+ or TN throughout the course of the disease. These findings, if confirmed, may influence treatment and pt selection for clinical trials.

Citation Format: Garrido-Castro AC, Hughes ME, Cherniack A, Barroso-Sousa R, Bychkovsky BL, Di Lascio S, Berger A, Mittendorf EA, Files JL, Guo H, Kumari P, Cerami E, Krop IE, Wagle N, Lindeman NI, MacConaill LE, Dillon DA, Winer EP, Lin NU. Genomic alterations associated with loss of HR expression in metastatic breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD9-01.

Abstract P5-12-02: PTEN alterations and tumor mutational burden (TMB) as potential predictors of resistance or response to immune checkpoint inhibitors (ICI) in metastatic triple-negative breast cancer (mTNBC)

Purpose: To date no biomarker has been identified that predicts response to ICI in mTNBC. This study aimed to explore if tumor genomic alterations correlate with efficacy of PD-1/PD-L1 inhibition in patients (pts) with mTNBC. Methods: Demographic, treatment response, and long-term outcome data were collected on patients with mTNBC treated at Dana-Farber Cancer Institute (DFCI) under several clinical trials incorporating PD-1/PD-L1 inhibitors, given as monotherapy or combined with chemotherapy (CT). Pts included in this analysis had available results of targeted exon sequencing performed using Oncopanel, our institutional gene sequencing panel, on archival tumor tissue. TMB was calculated by determining the number of non-synonymous somatic mutations that occur per megabase of exonic sequence data across all genes on the panel. High TMB was defined as 310 mutations/megabase. TMB and gene alterations were correlated with objective response rate (ORR) per RECIST 1.1, progression-free (PFS) and overall survival (OS). Results: A total of 50 pts with mTNBC were included in this analysis. At baseline, the median age was 55.9 years (31.8–75.9), 60% had ECOG 0 and 40% had ECOG 1, 72% had visceral metastasis, and 46% had received 31 prior lines of systemic therapy in the metastatic setting. While 26% of pts received monotherapy [pembrolizumab (n=7, NCT02447003); atezolizumab (n=6; NCT01375842)], 74% received combination with CT [pembrolizumab plus eribulin (n=31; NCT02513472); atezolizumab plus nab-paclitaxel (n=6; NCT01633970)]. PTEN alterations were present in 30% of pts (mutations = 7; one copy number loss = 7; two copy number loss = 1). Median follow-up was 14 months (1–40). Pts with tumors harboring PTEN alterations had lower ORR (7% vs 57%; P<0.001), shorter median PFS (2.3 vs 6.3 months; P=0.027), and shorter median OS (8.1 vs 20.1 months; P=0.012) compared to pts without PTEN alterations. The median TMB was 6.6 mut/Mb (1.2–50.8), and 23% of pts had a high TMB. While high TMB was not associated with higher ORR (P=0.56), it was associated with better median PFS (16.5 vs 2.4 months; P=0.017), and better median OS (not reached vs 13.5 months; P=0.026). Both PTEN status and TMB remained significantly associated with PFS in the multivariable model. Only PTEN status remained significantly associated with OS in the multivariable analysis with the same covariables. Ongoing analysis to better understand if these predictors are specific for predicting benefit to immunotherapy and/or a marker of chemotherapy resistance will be presented at the symposium. Conclusion: PTEN genomic alterations and TMB may impact benefit from PD-1/PD-L1 inhibitors largely administered with chemotherapy in mTNBC. These observations warrant prospective validation and may inform the importance of stratifying pts according to these characteristics in future randomized studies with ICI.

Table 1.Multivariable analysis for PFS Hazard ratioConfidence Intervalp-valueCombination therapy0.420.16 – 1.130.009Visceral metastasis1.310.63 – 2.770.46Previous lines of therapy1.020.09 – 0.700.85ECOG 12.11.06 – 1.280.034PTEN altered3.741.65 – 8.440.002Hypermutated tumors0.850.75 – 0.970.011

Citation Format: Barroso-Sousa R, Tyekucheva S, Pernas-Simon S, Exman P, Jain E, Garrido-Castro AC, Hughes M, Bychkovsky B, Di Lascio S, Umeton R, Files J, Lindeman NI, MacConaill LE, Hodi FS, Krop IE, Dillon D, Winer EP, Wagle N, Lin NU, Mittendorf EA, Tolaney SM. PTEN alterations and tumor mutational burden (TMB) as potential predictors of resistance or response to immune checkpoint inhibitors (ICI) in metastatic triple-negative breast cancer (mTNBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-12-02.

Abstract P4-01-17: Aggressive subgroups of metastatic triple-negative breast cancer: Inflammatory breast cancer and young patients in the Dana-Farber cell-free DNA cohort

Background: Relative to other metastatic breast cancer subtypes, metastatic triple-negative breast cancer (mTNBC) has a shorter duration of response to therapy and worse overall survival. Within mTNBCs, there is a prevailing belief that inflammatory breast cancer and young women tend to have among the most aggressive phenotypes. We investigated clinical and cell-free DNA (cfDNA) characteristics of inflammatory-mTNBC and young-mTNBC. We hypothesized that inflammatory-mTNBC may have distinct clinical and cfDNA characteristics, offering potential novel biomarker and therapeutic strategies.

Methods: 164 patients from the Dana-Farber metastatic triple-negative cell-free DNA cohort (Stover DG, et al J Clin Oncol 2018) were included in this secondary analysis. Patients were stratified into three groups: 1) inflammatory breast cancer ('IBC'); 2) non-IBC patients aged 45 years (yr) or younger at primary diagnosis ('non-IBC young'); and 3) non-IBC patients over age 45 yr at diagnosis. For each subset population, we evaluated clinicopathologic characteristics, sites of metastasis, survival outcomes, and cfDNA 'tumor fraction' – the fraction of DNA in circulation derived from tumor. Those patients with adequate cfDNA tumor content for high confidence copy number calls (n=101) were included in an analysis of copy number alterations.

Results: Among 164 patients with metastatic TNBC, 13.4% (22/164) had IBC, 37.8% (62/164) were non-IBC young, and 48.8% (80/164) were non-IBC and over 45 yr. Race and primary receptor status were similar. IBC patients were diagnosed at a higher stage (Chi-square p=0.0009) while non-IBC young patients were significantly more likely to harbor a BRCA mutation (Chi-square p=0.03). Analysis of metastatic sites revealed that IBC patients had significantly greater frequency of ipsilateral and contralateral breast chest wall recurrences (p=0.04 and p=0.046, respectively) while non-IBC young patients had the most frequent lung metastases (p=0.002). There were no significant differences in frequency of bone, brain, or liver metastases. cfDNA analyses showed that cfDNA 'tumor fraction' was highest in non-IBC young patients (ANOVA p=0.03 for maximum tumor fraction). Median overall survival from metastatic diagnosis was 22.9 months. IBC and non-IBC young patients had a worse prognosis relative to non-IBC patients over 45 yr (hazard ratio IBC=1.97, 95% CI 1.09-3.57; HR non-IBC young=1.60 95% CI 1.07-2.41; log-rank p=0.023). By subgroup, median overall survival from metastatic diagnosis for IBC was 15.2 months, non-IBC young 21.2 months, and non-IBC over 45 yr 31.2 months. Analyses of genome-wide copy number alterations from cell-free DNA will be presented.

Conclusions: Among metastatic TNBCs, IBC patients and non-IBC young patients have a significantly worse overall survival compared with non-IBC patients over 45 yr of age. Young patients have more frequent lung metastases and higher 'tumor fraction' of cfDNA. Confirmation of the reported findings is limited due to cohort size and may reflect referral bias.

Citation Format: Singh J, Asad S, Nock W, Zhang Y, Adams E, Damicis A, Parsons HA, Adalsteinsson VA, Winer EP, Lin NU, Partridge AH, Overmoyer B, Stover DG. Aggressive subgroups of metastatic triple-negative breast cancer: Inflammatory breast cancer and young patients in the Dana-Farber cell-free DNA cohort [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-01-17.

Abstract P4-04-02: Identifying ERBB-2 activating mutations (mts) in HER2 negative tumors for clinical trials – Impact of institute-wide genomic testing and trial matching on trial enrollment in clinical practice

Introduction

Tailored treatment trials with biomarker-driven hypotheses are becoming an important strategy in drug development. Umbrella, basket and enrichment trials with eligibility predicated upon results of tumor sequencing are increasingly common. Several institutional and commercial genomic assays have been developed. However, the value of broad-based testing in recruiting patients (pts) to molecular-based clinical trials designed for small subgroups has not been fully evaluated and has been challenging to assess in a real-world setting. We evaluated the likelihood of trial enrollment based upon an institute-wide genomic test.

Methods

Since 2013, all pts with metastatic breast cancer (MBC) seen at least once at Dana-Farber Cancer Institute have been offered the option of tumor sequencing using multiplexed copy number variation (CNV) and mts detection across the full coding regions of a total of 447 cancer genes and 191 regions across 60 genes for rearrangement detection (Oncopanel; OP). For our primary analysis, we selected the ongoing multi-center phase II trial (NCT01670877) activated at our site on Sep 30, 2013, evaluating neratinib in ERBB-2 mutated pts, as the study provided a clear delineation of eligible mts, and timing of slot availability was retrievable retrospectively over an extended time frame. Our primary aim was to describe the proportion of pts with a qualifying ERBB-2 mt detected by OP who enrolled on the selected trial. Secondary objectives included median time from OP result to trial registration and description of ERBB-2 mts spectrum within each subtype. Associations were calculated by Fisher's test.

Results

We identified a total of 1,046 pts with HER-2 negative MBC and who had OP results between Sep 1, 2013 and Jun 1, 2017. A total of 43 pts (4.1%) were found to have ERBB-2 mts. Of these, 20 (1.9%) had activating eligible mts. The proportion of these pts who enrolled in the trial was 30% (6/20). Of the remaining 14 pts, 5 screen-failed and 2 were enrolled with known ERBB-2 mt through other testing modalities. Seven of 20 (35%) molecularly eligible pts were not approached (3 pts lost to follow-up, 3 enrolled in other clinical trials and 1 pt chose standard treatment). The median time from OP result to trial enrollment was 85 days (34-554). A significantly higher frequency of ERBB2 activating mts was found in ER+ compared to ER- primary tumors (2.5% vs. 0.3%, p =0.036), and in lobular tumors compared with ductal (5.5% vs. 1.25%, p=0.003). Frequency of eligible mts in primary tumors were similar to metastatic site (1.9% and 1.8%, respectively p=1.0)

Discussion

In this cohort, activating ERBB-2 mts were present in 20 of 1046 (1.9%) pts tested. Although over half of pts with eligible mts on OP testing were approached for NCT01670877, only 0.5% of the total tested population were enrolled (6/1046). Our data illustrate the substantial challenges in screening and enrolling to trials of rare subsets, even within a large academic institution, and point to the need for creative and novel approaches to leverage pts and community- and academic-based providers to more effectively support the success of such studies.

Citation Format: Exman P, Garrido-Castro A, Hughes ME, Freedman RA, Ma C, Bose R, Cerami E, Wagle N, Barroso-Sousa R, Fitz CD, Lindeman NI, MacConaill L, Bychkovsky BL, Lloyd MR, Mackichan CR, Kumari P, Tolaney SM, Krop IE, Winer EP, Dillon DA, Lin NU. Identifying ERBB-2 activating mutations (mts) in HER2 negative tumors for clinical trials – Impact of institute-wide genomic testing and trial matching on trial enrollment in clinical practice [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-04-02.

Abstract P6-19-02: Tumor subtypes and survival in male breast cancer: SEER 2010-2014

Background: Male breast cancer (MaBC) is an uncommon disease, and population-based information regarding prognostic factors is limited. Most MaBC are hormone receptor (HR) positive, however, the association of tumor subtypes with overall survival (OS) and breast cancer-specific survival (BCSS) is unclear. The aim of this study was to analyze the characteristics of each tumor subtype and its impact on OS and BCSS.

Methods: Using Surveillance, Epidemiology, and End Results (SEER) data, we identified men with invasive breast cancer between 2010 and 2014 with known estrogen receptor and progesterone receptor (together HR) status and human epidermal growth factor receptor 2 (HER2) status. Tumor subtypes were classified as: HR+/HER2-, HR+/HER2+, HR-/HER2+ and triple negative (TN). We examined tumor subtypes by patient (pt) characteristics and performed multivariate Cox proportional hazards analyses to determine the associations of each variable with OS and BCSS.

Results: We included 1508 pts with a median follow-up of 24 months (range 0-60). Median age was 65 years (range 26-97). At diagnosis, 86.6% of tumors were ductal, 97.1% HR+, 42.1% T1, 55.7% N0, 7.9% M1. Tumor subtype distribution was: 85.5% HR+/HER2-, 11.6% HR+/HER2+, 0.9% HR-/HER2+ and 2% TN. Compared with other subtypes, pts with TN tumors had higher grade disease, presented with more advanced stage and died more often from breast cancer (all p<0.0001); whereas pts with HR+/HER2- tumors were older (p=0.02) and more often white (p=0.02). In univariate analysis, OS at 5 years for all HER2- and all HER2+ was 74.2% and 64.1%, respectively (p=0.002); while BCSS at 5 years for all HER2- and all HER2+ was 88.4% and 78.8%, respectively (p=0.009). Of all subtypes, TN had the worst OS and BCSS (p<0.0001). Breast cancer was the cause of death in 43.7% of HR+/HER2-, 54.2% of all HER2+ and 100% of TN (p<0.0001). In multivariate analyses for OS, older pts (Hazard ratio [HaR] 3 vs. <50 years; p=0.001), stage IV (HaR 9 vs. stage I; p<0.001), HR+/HER2+ tumors (HaR 1.9 vs. HR+/HER2-; p=0.003), TN tumors (HaR 8.5 vs. HR+/HER2-; p<0.001) and unmarried pts (HaR 1.9 vs. married; p=0.002) had significantly worse survival. In multivariate analyses for BCSS, stage IV (HaR 25.7 vs. stage I; p<0.001), HR+/HER2+ tumors (HaR 2.1 vs. HR+/HER2-; p=0.019), TN tumors (HaR 17 vs. HR+/HER2-; p<0.001) and unmarried pts (HaR 2.2 vs. married; p=0.009) had significantly worse survival.

Conclusion: We observed significant differences in outcomes by tumor type in men with breast cancer which mirror those previously observed for women with breast cancer. Among the limited numbers of men with HER2+ and TN disease in our sample, outcomes were poor, suggesting possible under-treatment, aggressive tumor biology, and/or more advanced of disease at presentation. Studies to better understand the inferior survival for men with these subtypes are warranted and efforts to ensure appropriate treatment are paramount.

Citation Format: Leone J, Freedman RA, Zwenger AO, Lin NU, Tolaney SM, Vallejo CT, Leone BA, Winer EP, Leone JP. Tumor subtypes and survival in male breast cancer: SEER 2010-2014 [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-19-02.

Abstract P1-17-02: Outcomes and safety of paclitaxel and granulocyte-colony stimulating factor (GCSF) in breast cancer in pregnancy (BCP) - A multi-institutional retrospective analysis

Background

BCP is uncommon; however, the frequency is increasing due to trends in delayed childbearing. Studies have suggested that some systemic therapies, including doxorubicin and cyclophosphamide, can be delivered safely during pregnancy after the first trimester, whereas agents such as trastuzumab and endocrine therapy are contraindicated due to risk to the fetus. Data remain limited on the efficacy and safety of administering taxane chemotherapy or growth factor support during pregnancy. We retrospectively evaluated the safety of systemic therapies, including paclitaxel and GCSF, as well as clinical outcomes, in a multi-institutional cohort of patients (pts) with BCP.

Methods

Pts treated for BCP from 1996-2018 from 3 large academic institutions were included. Demographic, oncologic treatment, and obstetric/neonatal outcomes data were obtained from medical records. Disease-free survival (DFS) and overall survival (OS) were estimated by Kaplan-Meier; Log-rank test were used to compare different groups/outcomes. Associations were calculated by Fisher's exact test.

Results

A total of 114 pts diagnosed with BCP were included. The median age was 35 years (range 25-44) and median gestational age at diagnosis was 18 weeks (range 2-38). BCP was predominantly early stage at diagnosis (stage I 28.0%, stage II 53.5%) and ER+/HER2- negative (48.2%). Sixty-three (55.2%) women received chemotherapy, 13 (11.4%) received paclitaxel and 11 (9.6%) GCSF (daily or depot injections) while pregnant. A total of 78% of pts with HER-2-positive BCP (28/36) received trastuzumab after delivery (11% were treated before 2005 and 5.5% were T1a). With median follow-up of 67.7 months, median DFS (stage I-III) was 212.8 months (CI 95% 108.4-317.1), and median OS (stage I-IV) was not reached. Subgroup analysis suggested a higher DFS for pts diagnosed in the 1sttrimester compared to the 3rdtrimester among women with stage II-III (HR 0.25 CI 95% 0.09-0.70, p= 0.03). Among women who received paclitaxel, there was no significant increase in adverse obstetrical/neonatal outcomes: preterm delivery (23.1% vs 13.1%, p 0.39), low weight newborn (7.7% vs 9.1 %, p 1.0), congenital malformations (0% vs 6.1%, p 1.0) or acute neonatal adverse outcomes (7.7% vs 4.0%, p 0.51), which include NICU need and Apgar 5'<7, compared to pts who did not receive paclitaxel. Among pts who received GCSF during pregnancy, adverse outcomes were numerically but not statistically higher than women who did not receive growth factor: preterm delivery (36.3% vs 11.0%, p 0.051), low weight newborn (27.3% vs 6.9%, p 0.058), congenital malformations (9.1% vs 1.0%, p 0.18) or acute neonatal adverse outcomes (18.2% vs 3.0%, p 0.07).

Conclusion

In this multi-institution cohort of BCP pts, despite a small number of pts, exposure to contemporary therapies including paclitaxel was not associated with unfavorable obstetrical/neonatal outcomes and these results suggest it is safe to administer during pregnancy under the care of a multidisciplinary team. Although not statistically significant, GCSF presented numerical worse outcomes and combining data from several cohorts would be helpful to provide confirmation of these findings.

Citation Format: Exman P, Freret TS, Economy KE, Chen WY, Parsons HA, Lin NU, Moy B, Tung NM, Partridge AH, Mayer EL. Outcomes and safety of paclitaxel and granulocyte-colony stimulating factor (GCSF) in breast cancer in pregnancy (BCP) - A multi-institutional retrospective analysis [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-17-02.

Abstract P6-15-11: Weekly paclitaxel, pertuzumab and trastuzumab (TPH) neoadjuvant therapy for HER2 positive inflammatory breast cancer

Background: Inflammatory breast cancer (IBC) is inoperable at presentation, thus neoadjuvant systemic therapy (NAS) is the primary treatment for this aggressive disease. Due to its rarity, patients (pts) with IBC are incorporated into NAS clinical trials for locally advanced breast cancer, making it difficult to extrapolate efficacy specifically for pts with IBC. A commonly used regimen for the treatment of HER2+ IBC includes docetaxel, carboplatin, pertuzumab (P) and trastuzumab (H), yet only 6% of pts enrolled in the clinical trial for this regimen had IBC. We sought to examine the efficacy of maximizing anti-HER2 therapy combined with minimal chemotherapy using the THP regimen specifically for pts with HER2+ IBC.

Methods: Pts with newly diagnosed HER2+ IBC received NAS with 16 weeks (wks) of paclitaxel (T) 80mg/m2/wk, H (2mg/kg/wk) and P(420mg/kg/3wk) followed by modified radical mastectomy (MRM) on a phase II prospective study. All pts had 2 research breast biopsies (rbx) for correlative assays prior to and 1 wk after the P (840mg/kg) and H (4 mg/kg) loading dose. Pts who achieved a pCR (pathologic complete response) could opt out of adjuvant doxorubicin (A) 60 mg/m2 + cyclophosphamide (C) 600mg/m2 x 4; pts with residual disease received AC. All pts received post-mastectomy radiation and maintenance P (420mg) + H (6mg/kg) every 3 wks x 12. Adjuvant endocrine therapy was given per standard of care. Primary objective was pCR rate in the breast and axillary lymph nodes. Residual Cancer Burden (RCB) was assessed. Based upon a Simon two-stage design, this regimen would be declared worthy of further study if >7/27 pCR were observed (15% vs 40%; target α=0.039 power=0.90). The study was closed after 23/27 pts were enrolled due to slow accrual.

Results: 20 pts were enrolled as of 12/2016, 18 completed NAS and MRM. All but 1 had stage III disease at presentation. 1 pt was lost to follow-up; 1 developed CNS metastasis during NAS and did not undergo MRM. The mean age was 49 years, 10 pts had ER/PR negative disease. 15 pts completed 16 wks of T, 4 had 15 wks and 1 had 13 wks. During NAS, there was no grade (gd) 4 toxicity; 6 episodes of gd 3 toxicity (2 related to treatment-diarrhea); and no gd 3 cardiac events. In the intent to treat analysis, 10/20 pts achieved pCR (50%; 90% CI 30-70%) and 6 had RCB-1 (30%). 5 pts with RCB-1 response had <5 mm residual disease; 1 had lymph node involvement. Of those proceeding to MRM, pCR rate was 56% (10/18). 6/10 opted out of AC. Treatment and follow-up for clinical outcomes continue. Biologic correlatives investigating genomic profiling and patterns of HER2 resistance are being performed on rbx, residual disease and cfDNA.

Conclusion: THP x 16wks is tolerable and effective NAS for HER2+ IBC, resulting in a high pCR rate with minimal toxicity. This study of NAS explored the benefit of maximizing HER2-directed therapy and minimizing chemotherapy and its associated toxicity. It has achieved its primary endpoint and will be used as the backbone NAS for HER2+ IBC, with future studies building upon this regimen. The result of this trial supports the benefit of clinical trials designed specifically for pts with IBC. Clinical trial information: NCT01796197.

Citation Format: Overmoyer B, Regan M, Hu J, Nakhlis F, Dominici L, Lin NU, Freedman R, Morganstern DE, Partridge AH, Schlosnagle EJ, Hirshfield-Bartek J, Bellon J, Morikawa A, Harrison BT, Winer E. Weekly paclitaxel, pertuzumab and trastuzumab (TPH) neoadjuvant therapy for HER2 positive inflammatory breast cancer [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 P6-15-11.

Abstract P4-10-04: EMBRACE (Ending metastatic breast cancer for everyone): A comprehensive approach to improve the care of patients with metastatic breast cancer

Background: In contrast to early stage breast cancer, the quality of care for patients with metastatic breast cancer (MBC) has been relatively understudied, as have interventions to improve care in the real-world setting. Patients with MBC face a variety of unique needs related to their disease, treatment options, and supportive care. Little attention has been focused on leveraging the strengths of academic and community-based settings to provide optimal care for these patients. To address these critical issues, we have designed and implemented a comprehensive program that combines clinical care, clinical research, physician engagement and patient education to optimize the care of MBC patients.

Methods: We developed a consistent and comprehensive intake process and follow-up approach for MBC patients who were seen at least once in the Breast Oncology Clinic (BOC) at Dana-Farber Cancer Institute (DFCI). A key component of our approach is the EMBRACE coordinator who meets with each MBC patient at the first clinic visit to review the clinical program, available educational and supportive resources, and consents to research studies. Each coordinator supports the DFCI-based oncologist and follows a discrete patient panel longitudinally, for whom they are responsible for facilitating referrals to supportive care resources, identifying potential candidates for trial prescreening, tracking availability of results from molecular testing for clinical trial matching, facilitating communication between DFCI-based providers and referring providers and organizing re-consultation visits when clinically appropriate. The coordinator contacts patients every 3 months to inquire about the patient's overall health and needs and provides updates on upcoming educational and supportive care activities at our institution. Educational offerings have been expanded to include a bi-annual newsletter, quarterly email updates, webcasts and an annual educational patient forum. Results: The program was fully implemented in the BOC across 27 oncologists in August 2016, after the start of a pilot in July 2015. On average, the program enrolls 30 to 40 new MBC patients per month at their initial visit. The EMBRACE coordinators currently support the DFCI-based oncologists in the care of approximately 1500 new and existing MBC patients and facilitate collaborations with 350 referring providers.

Conclusions: The EMBRACE program has made a tangible improvement in the quality of care for patients with MBC in our clinic. We have successfully established the infrastructure of the coordinator role and a robust tracking system to support the patient, DFCI-based provider, and referring provider. While the program has been solely based at DFCI, we believe that our approach has the potential for impact beyond our institution and ultimately serve as a model for enhanced academic-community-patient partnership.

Citation Format: Hughes ME, Frank ES, Merrill MS, Santiago RA, Kuhnly N, Crowley LM, Gupta G, Winer EP, Lin NU. EMBRACE (Ending metastatic breast cancer for everyone): A comprehensive approach to improve the care of patients with metastatic breast cancer [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 P4-10-04.

Abstract P5-21-10: Phase 2 study and correlative analyses of ruxolitinib, a selective JAK1/2 inhibitor, in patients with metastatic, triple-negative breast cancer

Background: Preclinical data supports a role for the IL-6/JAK2/STAT3 signaling pathway in breast cancer (BC). Ruxolitinib is an orally bioavailable receptor tyrosine inhibitor targeting JAK1 and JAK2. We evaluated the safety and efficacy of ruxolitinib in patients with metastatic BC and performed correlative analyses.

Methods: This was a non-randomized, phase 2 study of patients with refractory, metastatic, triple-negative BC (TNBC). Patients with inflammatory BC (IBC) of any subtype were also enrolled. The primary endpoint was objective response by RECIST 1.1. Secondary endpoints included progression-free survival (PFS), overall survival (OS), and toxicity. The study was designed to enroll only patients whose archival tumor tissue was pSTAT3 moderately to strongly positive in the tumor epithelial cells by central immunohistochemistry (IHC). 16 patients underwent pre-treatment biopsy, of whom 4 also had a second biopsy prior to cycle 2. Biopsy samples and paired primary tumor samples (when available) were subjected to multi-color immunofluorescence and/or immune-FISH for leukocyte markers, pSTAT3, and JAK2. RNA sequencing was performed on available on-study frozen biopsy specimens. 17 patients had plasma collected with cell-free DNA (cfDNA) extracted and subjected to low coverage whole-genome sequencing.

Results: Of 217 patients who consented to archival tumor testing, T-score for pSTAT3 was 'high' (>5) in 69 patients (31.8%), demonstrating frequent activation of the JAK/STAT pathway in metastatic TNBC or IBC. 23 pSTAT3 high patients were enrolled. Ruxolitinib was generally well-tolerated. The most commonly observed adverse events (any grade) were anemia, neutropenia, thrombocytopenia, constipation, nausea, and increased AST/ALT. Grade 3 or higher toxicities were uncommon. No objective responses were seen among 21 evaluable patients, therefore the study was closed to accrual based on study design. Intensive correlative analyses revealed important insights regarding ruxolitinib effects. Pharmacodynamic analyses of baseline versus cycle 2 biopsies demonstrate downregulation of JAK2 target genes, STAT3 signatures, and JAK/STAT gene ontology gene sets, suggesting on-target activity. There was evidence of immune microenvironment modulation: gene set enrichment analysis implicated reduced macrophage/myeloid phenotypes after treatment and CIBERSORT analysis of inferred immune cell subsets demonstrated reduced monocyte/macrophage proportion after treatment (t-test p=0.013). Multi-color immunofluorescence analyses of immune microenvironment are ongoing and will be reported. 17 patients underwent cfDNA analysis with 8 patients (47%) demonstrating gain or amplification of JAK2.

Conclusions: Ruxolitinib, as a single agent, did not meet the primary efficacy endpoint in this refractory patient population. Correlative studies demonstrate evidence of on-target activity and immune microenvironment modulation. Frequent JAK/STAT pathway activation and JAK2 locus chromosomal gains in this cohort suggest that the JAK/STAT pathway remains a potential therapeutic target in BC.

Citation Format: Stover DG, Gil Del Alcazar CR, Tolaney SM, Bardia A, Guo H, Balko JM, Overmoyer BA, Gelman RS, Lloyd M, Wang V, Brock JE, Winer EP, Polyak K, Lin NU. Phase 2 study and correlative analyses of ruxolitinib, a selective JAK1/2 inhibitor, in patients with metastatic, triple-negative breast cancer [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 P5-21-10.

Abstract GS3-07: Genome-wide copy number analysis of chemotherapy-resistant metastatic triple-negative breast cancer from cell-free DNA

Introduction:

Triple-negative breast cancer (TNBC) is a poor prognosis breast cancer subset characterized by relatively few mutations but extensive copy number alterations (CNAs). Cell-free DNA (cfDNA) offers the potential to overcome infrequent tumor biopsies in metastatic TNBC (mTNBC) and interrogate the genomics of chemotherapy resistance.

Methods:

506 archival or fresh plasma samples were identified from 164 patients with mTNBC who had previously received chemotherapy. We performed low coverage whole genome sequencing to determine genome-wide copy number and estimate 'tumor fraction' of cfDNA (TFx) using our recently-developed approach, ichorCNA. In patient samples with TFx >10%, we identified regions that were significantly gained or lost using GISTIC2.0. We compared CNAs of 20 paired primary-metastatic samples and also mTNBCs from cfDNA versus primary TNBCs from TCGA and METABRIC.

Results:

We successfully obtained high quality, low coverage whole genome sequencing data for 478 (94.5%) plasma samples from 158 patients, with 1 to 14 samples per patient. TFx and copy number profiles were highly concordant with paired metastatic biopsy (n=10, range 0-7 days from biopsy to blood draw) with sensitivity of 0.86 and specificity of 0.90 and reproducible in independently-processed blood draws (TFx intraclass correlation coefficient 0.984). Median overall survival from time of first blood draw was 8 months, and TFx was highly correlated independent of primary stage, primary receptor status, age at primary diagnosis, BRCA status, and metastatic line of therapy: adjusted hazard ratio between 4th and 1st quartiles = 2.14 (95% CI 1.40-3.28; p=0.00049). 101/158 patients (63.9%) had at least one sample with TFx >10%, our threshold for high confidence CNA calls. Copy number profiles and percent genome altered were remarkably similar between mTNBCs and primary TNBCs in TCGA and METABRIC (n=433), suggesting that large-scale chromosomal events are infrequent in TNBC metastatic progression. We identified chromosomal gains that demonstrated significant enrichment in mTNBCs relative to paired primary TNBCs (n=20) and also TCGA/METABRIC, including driver genes (NOTCH2, AKT2, AKT3) and putative antibody-drug conjugate targets. Finally, we identify a novel association of gains of 18q11 and/or 19p13 with poor metastatic prognosis, independent of clinicopathologic factors and TFx.

Conclusions:

Here, we present the first large-scale genomic characterization of metastatic TNBC to our knowledge, derived exclusively from cfDNA. 'Tumor fraction' of cfDNA is an independent prognostic marker in mTNBC. Primary and metastatic TNBC have remarkably similar copy number profiles yet we identify alterations enriched and prognostic in mTNBC. Collectively, these data have potential implications in the understanding of metastasis, therapeutic resistance, and novel therapeutic targets.

Citation Format: Stover DG, Parsons HA, Ha G, Freeman S, Barry B, Guo H, Choudhury A, Gydush G, Reed S, Rhoades J, Rotem D, Hughes ME, Dillon DA, Partridge AH, Wagle N, Krop IE, Getz G, Golub TA, Love JC, Winer EP, Tolaney SM, Lin NU, Adalsteinsson VA. Genome-wide copy number analysis of chemotherapy-resistant metastatic triple-negative breast cancer from cell-free DNA [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 GS3-07.

Abstract OT1-01-09: Feasibility and safety of avoiding granulocyte colony-stimulating factor prophylaxis during the paclitaxel portion of dose dense doxorubicin-cyclophosphamide and paclitaxel regimen

Background: The need for granulocyte-colony stimulating factor (G-CSF) support during dose-dense (DD) paclitaxel (T) after doxorubicin and cyclophosphamide (AC) is unclear. Given that G-CSF is not devoid of adverse effects, and adds significant costs to treatment, we are examining the feasibility and safety of avoiding G-CSF during dose dense T. Methods: This is a single center, single-arm, phase II, two stage study. The primary aim is to evaluate the rate of T treatment completion within 7 weeks (from D1 of cycle 1 to D1 of cycle 4 of T) omitting Pegfilgrastim using pre-specified safety rules. Secondary aims include: characterization of the utilization of Pegfilgrastim using pre-specified safety rules in patients receiving dose dense T; evaluation of the safety of omitting routine Pegfilgrastim support in patients receiving dose dense T; evaluation of total cost ($ United States) of omitting routine Pegfilgrastim use during dose dense T. As a secondary aim we will evaluate the safety of simplifying the pre-medication regimen used for the T portion of the regimen (withholding corticosteroids in cycle 3 and 4 if no evidence of allergic reactions in cycle 1 and 2). A Simon Optimal design was selected with an overall one-side type I error of 10% and 90% power to detect the difference between unacceptable T completion rate (75%) and desirable completion rate (85%). In the first stage, 51 evaluable patients will be enrolled. If during the first stage, at any point, a total of 12 or more patients do not complete treatment within 7 weeks the trial will be closed permanently. Among the 51 patients enrolled after the first stage, if at least 40 patients complete treatment without dose delay, accrual will continue to the second stage where an additional 74 evaluable patients will be enrolled. If there are at least 100 among the 125 evaluable patients completing treatment without dose delay, the regimen will be considered worthy of further study. If during the second stage, at any point, a total of 26 patients do not complete treatment within 7 weeks the trial will be closed permanently and the study intervention will not be of clinical interest. If the true treatment completion rate is 75%, the chance the regimen is declared ineffective is 91% (exact alpha = 0.094) and if the true treatment completion rate is 85% the chance that the regimen is falsely declared ineffective is 10% (exact power = 0.899). The estimated accrual rate is 6-8 patients/month. Accrual started in April 2016. Clinical trial information: NCT02698891.

Citation Format: Barroso-Sousa R, Vaz-Luis I, Guo H, Barry WT, Brackett AM, Brock VA, Roche KA, Kasparian E, Winer EP, Lin NU. Feasibility and safety of avoiding granulocyte colony-stimulating factor prophylaxis during the paclitaxel portion of dose dense doxorubicin-cyclophosphamide and paclitaxel regimen [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT1-01-09.

Abstract OT3-01-04: An open-label, single-arm, phase II study of pertuzumab with high-dose trastuzumab for the treatment of central nervous system progression post-radiotherapy in patients with HER2-positive metastatic breast cancer (PATRICIA)

Background: Central nervous system (CNS) metastases are observed in up to half of patients with HER2-positive metastatic breast cancer (MBC), with incidence likely to continue to rise due to longer survival through improved systemic treatments. While radiotherapy-based approaches can be effective, there are potential short- and long-term toxicities, and patients frequently progress. CNS response to existing systemic therapies has been generally poor, and there is a high unmet need with no approved treatment for CNS metastases in HER2-positive MBC. Combination of the HER2-targeted monoclonal antibodies trastuzumab and pertuzumab provides a more comprehensive blockade of HER2 than either antibody alone, and data from the phase III CLEOPATRA trial suggest that adding pertuzumab to trastuzumab and docetaxel may delay onset of CNS disease. Trastuzumab concentrations in the CNS are increased under conditions of an impaired blood–brain barrier (BBB) and subtherapeutic levels in the CNS may be related to insufficient dosing rather than inability to cross the BBB. The PATRICIA trial is evaluating the addition of pertuzumab with high-dose trastuzumab to a patient's current systemic treatment for HER2-positive MBC patients with CNS progression post-radiotherapy and stable systemic disease.

Study design: In this US-based, phase II, open-label, single-arm study, patients will receive intravenous pertuzumab (840 mg loading dose followed by 420 mg every 3 weeks) in combination with intravenous high-dose trastuzumab (6 mg/kg weekly) in addition to their current systemic therapy (except for ado-trastuzumab emtansine or lapatinib) until disease progression or unacceptable toxicity.

Eligibility criteria: Patients aged ≥18 years with confirmed HER2-positive MBC with new and/or progressive CNS lesions >60 days after whole-brain radiotherapy or stereotactic radiosurgery for CNS metastases, performance status 0–1, and stable systemic disease will be eligible. Patients must have a baseline left ventricular ejection fraction (LVEF) ≥50%, no significant history of cardiac disease or current use of anthracyclines, life expectancy >12 weeks, and not be pregnant or lactating.

Aims: The primary efficacy endpoint will be objective response rate (ORR) in the CNS, assessed by the investigator using RANO–BM criteria. Secondary endpoints will include duration of CNS response, progression-free survival (CNS and/or non-CNS), overall survival, and safety. Pharmacokinetic and patient-reported outcomes will also be evaluated. LVEF will be assessed throughout treatment and follow-up. An interim analysis will be performed when 15 patients have completed 2 cycles, and the study will be stopped if no clinical benefit (complete response, partial response, or stable disease in the CNS) is seen or if two or more patients have congestive heart failure events related to trastuzumab or pertuzumab.

Statistical methods: The recruitment target is 40 patients; with 35 evaluable, the 95% confidence interval around an estimated ORR of 20% will be 8.4–36.9%. The trial opens for accrual in Q3 2015.

Citation Format: Lin NU, Pegram MD, Lai C, Lacasia A, Stein A, Yoo B, Perez EA. An open-label, single-arm, phase II study of pertuzumab with high-dose trastuzumab for the treatment of central nervous system progression post-radiotherapy in patients with HER2-positive metastatic breast cancer (PATRICIA). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT3-01-04.

Abstract P1-08-07: Predisposing germline mutations in a clinic based breast cancer (BC) population

Background: Evaluation of women with BC for germline mutations associated with hereditary breast and ovarian cancer (HBOC) has become increasingly common due to its impact on management. Guidelines for genetic evaluation indicate testing for cases with early onset, triple negative disease or family cancer history. However, the majority of breast cancer occurs in patients without these high risk characteristics. The prevalence of mutations associated with HBOC has not been well characterized in this population.

Methods: We performed a cross sectional study using DNA from blood samples from consecutive new invasive BC patients seen at the Dana-Farber Cancer Institute (01/01/2010 to 07/31/2102) who consented to research. Subjects were otherwise unselected. Mutations in 25 cancer genes were identified using a next generation sequencing based panel. Germline sequence variations and large rearrangements were classified for pathogenicity.

Results: 456 samples from eligible subjects were included. The mean age of BC diagnosis was 50 years. Mutations were found in 51 women, 49 of which were associated with breast cancer (10.8%, 95% CI 8.1-14.0). BRCA1/2 mutations were found in 6.6% [95% CI 4.5-9.2%] while mutations in other BC-associated genes were found in 4.4% [95% CI 2.7-6.7%], particularly CHEK2 (2.2%, 95% CI 1.1, 4.0). Of the 49 women with BC-related mutations, 21 (43%) had BC diagnosed after age 45. In univariate analyses, age at diagnosis, Ashkenazi Jewish ancestry, triple negative histology and family BC/ovarian cancer (OC) history were associated with BRCA1/2 mutations, but no factors were significantly associated with mutations in other genes. Among 261 women with no FDR/SDR with BC/OC, 26 (10.0%) had a mutation. Nineteen mutations (10 BRCA1/2) were found in the 256 women (7.4%) who had not had previous genetic testing.

Conclusions: In a single academic institution, 11% of new breast cancer patients had a germline mutation in a breast cancer predisposition gene: 6.6% were in BRCA1/2. The elevated prevalence compared to population-based series may reflect the practice composition of academic centers, which often attract women younger at BC diagnosis. In an academic practice with an active cancer genetics program, 10 women with BRCA1/2 and 9 with other mutations had not had genetic testing. Expanded testing identifies additional predisposing mutations, the utility of which are being defined for the care of breast cancer patients and their families.

Citation Format: Garber JE, Tung NM, Elkin EP, Allen BA, Singh NU, Wenstrup R, Hartman A-R, Winer EP, Lin NU. Predisposing germline mutations in a clinic based breast cancer (BC) population. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-08-07.

Abstract P1-07-08: Time trends in incidence rates and survival for women with de novo metastatic lobular vs. ductal carcinoma, a population-based study

Background: Survival for metastatic breast cancer (MBC) patients (pts) has modestly improved over time. Until the early 2000's, incidence rates for invasive lobular carcinoma (ILC) had steadily risen, in contrast to the stable rates observed for invasive ductal carcinoma (IDC). Historically, ILC was deemed to have a more favorable prognosis than IDC. Nevertheless, data on recent time trends in incidence and survival of lobular vs. ductal histology among newly diagnosed MBC pts are limited.

Pts and Methods: Using the Surveillance, Epidemiology, and End Results (SEER) 9 registries, we included 10,767 pts diagnosed with de novo lobular or ductal MBC from 1990-2011, and followed through 2012. Time trends in annual age-adjusted incidence rates were analyzed, stratified by histology. Multivariable Cox regression models were fit to investigate the association of year of diagnosis and overall survival (OS) by stratum, adjusting for features presented in Table 1. We examined interactions between year of diagnosis and histology. In sensitivity analyses, we modeled year of diagnosis as categorical, and restricted the cohort to hormone-receptor positive pts.

Table 1IDC N= 9,376 (87%)ILC N= 1,391 (13%)Cohort characteristics%Age, yearsƚ <407240-49151050-59232160-692327≥703240Raceƚ White7585Black1710Other/Unknown85Gradeƚ I410II3027III/IV4914Unknown1749Hormone Receptorƚ +7391-279IncidenceRates (per 100,000/year)Year of diagnosis 19901.650.1320001.540.2120112.170.34SurvivalHR of death (95% CI)*Year of diagnosis 1-year trend0.98(0.98-0.99)1.01(0.99-1.02)5-years trend0.94(0.92-0.96)1.05(0.99-1.11)p<.01 for differences between groups*Adjusted for: cohort characteristics, SEER registry, and marital status

Results: 9,376 (87%) pts had IDC and 1,391 (13%) had ILC. Overall, we found a 1.4 fold increase in incidence rates for de novo MBC over the study period, (with a 1.3- and 2.6-fold increase for IDC and ILC, respectively). OS improved over the study period for the overall cohort (Hazard ratio (HR) of death=0.99; 95% confidence interval (CI)=0.98-0.99; 1% decrease/year; 5% decrease/5 years; p=.0059 for the interaction year of diagnosis-histology on OS). ILC pts had better outcomes than IDC pts (median OS=28 vs. 21 months; adjusted HR of death= 0.93; 95%CI=0.87-0.99). For IDC pts, we found a statistically significant improvement in OS over time (HR of death=0.98; 95%CI=0.98-0.99; 2% decrease/year; 6% decrease/5 years). However, we observed no significant change in survival outcomes for ILC pts (HR of death=1.01; 95%CI=0.99-1.02) (Table 1). Results from sensitivity analyses were similar.

Conclusions: From 1990-2011, incidence rates for de novo MBC increased. In this cohort, ILC pts had a better prognosis than IDC pts. Nevertheless, although we found an expected overall improvement in OS for MBC pts, this effect was restricted to IDC pts, with no significant improvement among ILC pts. Dedicated studies are warranted to understand whether our results can be confirmed in other datasets and to investigate the reasons driving this discrepancy, such as the impact of patterns of care, new drug approvals, and tumor molecular subtype.

Citation Format: Di Meglio A, Freedman RA, Lin NU, Barry WT, Metzger-Filho O, Keating NL, Winer EP, Vaz-Luis I. Time trends in incidence rates and survival for women with de novo metastatic lobular vs. ductal carcinoma, a population-based study. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-07-08.

Trastuzumab emtansine (T-DM1) versus lapatinib plus capecitabine in patients with HER2-positive metastatic breast cancer and central nervous system metastases: a retrospective, exploratory analysis in EMILIA

BACKGROUND

We characterized the incidence of central nervous system (CNS) metastases after treatment with trastuzumab emtansine (T-DM1) versus capecitabine-lapatinib (XL), and treatment efficacy among patients with pre-existing CNS metastases in the phase III EMILIA study.

PATIENTS AND METHODS

In EMILIA, patients with human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer previously treated with trastuzumab and a taxane were randomized to T-DM1 or XL until disease progression. Patients with treated, asymptomatic CNS metastases at baseline and patients developing postbaseline CNS metastases were identified retrospectively by independent review; exploratory analyses were carried out.

RESULTS

Among 991 randomized patients (T-DM1 = 495; XL = 496), 95 (T-DM1 = 45; XL = 50) had CNS metastases at baseline. CNS progression occurred in 9 of 450 (2.0%) and 3 of 446 (0.7%) patients without CNS metastases at baseline in the T-DM1 and XL arms, respectively, and in 10 of 45 (22.2%) and 8 of 50 (16.0%) patients with CNS metastases at baseline. Among patients with CNS metastases at baseline, a significant improvement in overall survival (OS) was observed in the T-DM1 arm compared with the XL arm [hazard ratio (HR) = 0.38; P = 0.008; median, 26.8 versus 12.9 months]. Progression-free survival by independent review was similar in the two treatment arms (HR = 1.00; P = 1.000; median, 5.9 versus 5.7 months). Multivariate analyses demonstrated similar results. Grade ≥3 adverse events were reported in 48.8% and 63.3% of patients with CNS metastases at baseline administered T-DM1 and XL, respectively; no new safety signals were observed.

CONCLUSION

In this retrospective, exploratory analysis, the rate of CNS progression in patients with HER2-positive advanced breast cancer was similar for T-DM1 and for XL, and higher overall in patients with CNS metastases at baseline compared with those without CNS metastases at baseline. In patients with treated, asymptomatic CNS metastases at baseline, T-DM1 was associated with significantly improved OS compared with XL.

Abstract P1-04-01: Significance of circulating tumor cells in metastatic triple negative breast cancer: Results of an open label, randomized, phase II trial of nanoparticle albumin-bound paclitaxel with or without the anti-death receptor 5 tigatuzumab (TBCRC 019)

Background: Circulating Tumor cells (CTCs) are prognostic at baseline and first follow-up in patients with metastatic breast cancer (MBC). Using the most commonly used assay (CellSearch®), we have previously reported the ability to detect apoptotic vs. non-apoptotic CTCs in patients with MBC. However, there has been concern regarding the performance of the CellSearch® assay in patients with triple negative (TN) MBC. We hypothesized that CellSearch® is an effective assay in patients with TN MBC, and that CTC-apoptosis might further separate prognosis. Therefore, we studied CTCs in patients with TN MBC who participated in a prospective randomized phase II trial testing for activity of tigatuzumab (TIG) in combination with nanoparticle albumin-bound paclitaxel (nab-PAC) conducted by the Translational Breast Cancer Research Consortium (overall results reported by Forero A., et al, ASCO 2013).

Methods: Whole blood (WB) was drawn into a CellSave tube at baseline, day 15, and day 29 and CTC counts were determined using the CXC CellSearch® kit. Apoptosis was characterized by staining with a monoclonal antibody that detects a neo-epitope on fragmented cytokeratin (M-30) and independently by visual inspection (nucleic condensation and/or fragmentation, as well as granular cytokeratin). Association between levels of CTCs and CTC-apoptosis with the overall response rate (ORR) and progression free survival (PFS) at baseline, day 15, and day 29 was assessed using logistic regression, Kaplan Meier curves, and Cox proportional hazards modeling.

Results: Of the 60 patients entered into the trial, 52 were evaluable for CTCs. Of these, 19/52 (36.5%), 14/52 (26.9%), and 13/49 (26.5%) had elevated CTCs (≥5CTC/7.5 ml WB) at baseline, day 15, and day 29, respectively. Patients with elevated CTCs at each time point had worse PFS than patients with low or no CTCs. Hazard rates (HR) at baseline, day 15, and day 29 were 2.38 (95% CI: 1.27-4.45, p = 0.007), 2.87 (95% CI: 1.46-5.66, p = 0.002), and 3.40 (95% CI: 1.68-6.89, p = 0.001), respectively. The odds of overall response for those who had elevated CTCs compared to those who did not at baseline, day 15, and day 29, were 0.25 (95% CI: 0.073-0.81, p = 0.024), 0.18 (95% CI: 0.04-0.67, p = 0.014), and 0.06 (95% CI: 0.01-0.28, p = 0.001), respectively. There was no apparent prognostic effect comparing the degree of CTC-apoptosis vs. non-apoptosis.

Conclusions: Similar to observations in other intrinsic subgroups, CTCs were detected in a large fraction of TN MBC patients at baseline using CellSearch® assay, and reductions in CTC levels reflected response. In these homogenously prospectively enrolled TN MBC patients, regardless of treatment, CTCs are prognostic at baseline, day 15, and day 29. It does not appear that analysis of CTC-apoptosis is prognostic.

Supported by Susan G. Komen for the Cure, Veridex, LLC, Fashion Footwear Charitable Foundation of New York/QVC Presents Shoes on Sale™ (DFH), Associazione Sandro Pitigliani and by a studentship from FIRC (CP), Triple Negative Breast Cancer Foundation, The AVON Foundation, and The Breast Cancer Research Foundation.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-04-01.

Abstract OT3-2-05: Randomized phase II study of fulvestrant with or without ganetespib in patients (pts) with hormone receptor (HR)-positive metastatic breast cancer

Background: In pts with HR-positive metastatic breast cancer, endocrine resistance is a major clinical problem. Ganetespib is a small molecule inhibitor of heat shock protein 90 (HSP90), a molecular chaperone protein that regulates post-translational folding of numerous client proteins including estrogen and progesterone receptor. In preclinical HR-positive breast cancer models, ganetespib impairs endocrine resistance and reduces heterogeneity in the disease control achievable by hormonal therapies.

Trial Design and Eligibility: This is a randomized phase II study designed to evaluate the efficacy of ganetespib in combination with fulvestrant compared to fulvestrant alone. Pts with endocrine-resistant, HR-positive metastatic breast cancer and up to 1 prior line of metastatic chemotherapy are eligible. Endocrine resistance is defined as relapse while on or within 1 year of completion of adjuvant endocrine therapy (ET) or progression through at least one line of ET for advanced disease. Patients are treated with fulvestrant 500 mg IM on Cycle 1 Day 1 (C1D1) and C1D15, C2D1, and D1 of each subsequent 28-day cycle. Ganetespib is administered at a starting dose of 200 mg/m2 IV on Days 1, 8, and 15 of each cycle. Pts undergo optional research biopsies at baseline and time of progression. Pts with accessible disease undergo a required research biopsy on C2D9. Circulating tumor cells (CTCs) and peripheral blood mononuclear cells (PBMCs) are collected at baseline, C2D8, C2D9, and time of progression. Pts who progress on fulvestrant may cross over to the combination.

Aims: The primary endpoint is progression-free survival. Secondary endpoints include safety and tolerability, objective response rate by RECIST 1.1, clinical benefit rate, and overall survival. Correlative aims include comparison of biomarkers on the C2D9 biopsy in pts treated with fulvestrant alone versus the combination of fulvestrant plus ganetespib, analysis of CTCs and pharmacodynamic markers in PMBCs.

Statistical Methods: Pts will be randomized 1:2 to receive fulvestrant alone or the combination of fulvestrant plus ganetespib. The total accrual goal is 71 pts. The expected accrual rate is 3.5-4.5 pts per month over a period of ∼20 months; it is anticipated at ∼15% of pts may be censored for PFS, with similar probability on both arms. There will be 80% power to detect a prolongation of true median PFS from 4.0 months to 8.0 months, using a one-sided 0.05 log-rank test.

Acrrual: To date, 15 of 71 planned pts have been enrolled.

Funding: The trial is supported by a grant from the Susan G. Komen foundation and funding from Synta Pharmaceuticals.

Contact information: nlin@partners.org.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT3-2-05.

Abstract P6-11-09: Impact of tumor subtype on clinical features, treatment, and clinical outcomes among breast cancer patients with central nervous system disease

Background: Breast cancer is the second most common cancer associated with brain metastases. For some patients, central nervous system (CNS) progression is the primary clinical problem, and the optimal management of these patients remains a challenge. In this study we examined the differences in clinical characteristics, the features of CNS-directed therapy, and outcomes among breast cancer patients with brain metastases according to tumor subtype.

Methods: A retrospective series of 214 breast cancer patients with brain metastases treated at the Dana-Farber Cancer Institute from 1999-2011 was identified. Tumor subtype was classified as hormone receptor (HR)+ (ER+/PR+/HER2-), triple negative (ER-/PR-/HER2-) or HER2+ (HER2+, any HR). Descriptive analysis was performed; Chi-square, Kruskal-Wallis, and Kaplan-Meier methods were used to compare clinical characteristics, CNS-directed therapy features, and outcomes between groups.

Results: Median follow-up time since CNS progression was 8 months (0-117). Median age at CNS diagnosis was 52 years (30-82). Tumor subtype distribution was as following: 35% HR+, 36% HER2+, and 29% triple negative. Table 1 represents the clinical characteristics, CNS-directed therapy features, and outcomes according to tumor subtypes. More patients with triple negative disease (32%) had CNS involvement at presentation of metastatic disease. 8% of HER2+ patients had CNS as the only site of disease. A higher proportion of patients with HER2+ disease received more than one modality of CNS directed treatment as initial therapy. These patients also received more lines of CNS-directed therapy during the entire course of their disease. The median survival time after CNS progression differed by subtype; patients with HER2+ disease had the longest median survival times.

Conclusions: Tumor subtype appears to impact clinical presentation, type and number of CNS-directed therapies, and survival among patients with breast cancer with brain metastases.

Table 1 Tumor subtype HR+ (n = 74, 35%)HER2+ (n = 78, 36%)Triple negative (n = 62, 29%)P-valueBreakdown of treatment periods 0.2011999-200334%45%29% 2004-200628%17%31% 2007-201138%38%40% Clinical features at CNS disease presentationCNS disease at presentation of metastatic disease,%1522320.052Only site of metastatic disease,%181 Time from metastatic disease until CNS disease (median, min-max; months)16 (0-113)12 (0-65)6 (0-60)<0.001Type of CNS disease,%   0.004Brain only849589 Leptomeningeal disease only040 Brain and leptomeningeal disease16111 Number of CNS lesions,%   0.4141202921 2-3151413 4+625666 Unknown300 CNS-directed therapy1st CNS-directed therapy,% 0.126Surgery553 Whole brain radiotherapy725660 SRS896 Experimental drug135 More than one modality directed to CNS82721 Never received a CNS-directed therapy505 CNS-directed therapy (first and subsequent treatments combined),%    Surgery113360.003SRS154421<0.001Whole brain radiotherapy8788850.866Intrathecal therapy114150.085Systemic therapy3215<0.001Number of CNS-directed treatments (median, min-max)1 (0-6)2 (1-9)1 (0-5)<0.001Clinical outcomesSurvival times (median, min-max; months)6 (0-83)22 (1-117)4 (0-110)<0.001Events,%9697980.016

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-11-09.

Abstract P4-19-01: Attitudes of medical oncologists towards research biopsies

Background:

There is increasing interest in studying tissue from patients (pts) with metastatic breast cancer (MBC). Historically, limited tissue has been available. Possible barriers to research biopsies (bx) include pt and provider opinions; the contribution of each factor is unknown.

Methods:

309 academic breast medical oncologists (MOs) identified from the websites of each of the National Cancer Institute - designated cancer centers were invited to complete either a self-administered paper or online survey. Eligible MOs (MOs who saw breast cancer pts and who saw pts 4 hours/week.) were asked to predict what proportion of their pts with MBC would consent to additional bx (ABs, additional bx performed with a clinically indicated bx) or research purposes only bx(RPOBs, research bx performed as a standalone procedure). They were also asked about their comfort levels in asking pts with MBC to consider participating in ABs or RPOBs for various organs. Median values are reported. Two-sided Fisher's exact test was used to compare categorical variables using a a level of .05.

Results:

191 (101F,85M, 5 unknown) eligible MOs completed the survey. 29 MOs were ineligible (response rate = 191/280,68%). Median age was 50 (Range 33-80). Median years of oncology experience was 15 (Range 1-45). MOs predicted that 90%, 75%, 70% and 50%, of their pts would definitely/probably consider ABs of blood, skin, breast, or liver respectively. MOs predicted that 90%, 60%, 33%, and 20% of their pts would definitely/probably consider RPOBs of blood, skin, breast, or liver. 98% (95% CI 96%-100%), 96% (95% CI 92%-98%), 93% (95% CI 88%-96%) and 70% (95% CI 63%-77%) of MOs were very/somewhat comfortable asking pts for an AB of blood, skin, breast and liver respectively. 98% (95% CI 95%-99%), 93% (95% CI 89%-96%), 78% (95% CI 72%-84%) and 50% (95% CI 43%-58%) of MOs were very/somewhat comfortable asking pts to participate in a RPOB of blood, skin, breast and liver respectively.

No demographic characteristics (eg. sex, age) were associated with MOs’ comfort levels of asking pts to have an AB of blood, skin and breast.

Factors associated with increased comfort discussing an AB of the liver were: age < 50 years (p = 0.01), in practice for < 15 years (p = 0.01), ≥ 1 pt enrolled on clinical trials per month (p = 0.02), or having pts who had undergone bx for research in prior 3 months (p<0.01).

MOs with ≥ 4 patients enrolled on clinical trials/month or whose pts had undergone research bx in the past 3 months were more likely to feel comfortable asking pts to have a RPOB of the breast (p<0.01; p<0.01) or liver (p = 0.03; p<0.01).

The 3 most common reasons why MOs were reluctant to refer pts for participation in an AB include risk of a bx procedure (n = 128, 67%), pain/discomfort of a bx (n = 125, 65%), and logistical barriers (n = 42, 22%). These reasons are similar for RPOB; risk of a bx procedure, (n = 137, 72%), pain/discomfort of a bx (n = 134, 70%), and inconvenience to pt (time involved, travel, etc) (n = 58, 30%).

Conclusions:

Many MOs predict that the majority of their MBC pts will consider ABs of various organs. However, this decreases with RPOBs, particularly as the procedure becomes more invasive. More research is needed to understand factors that may influence MOs’ comfort levels asking pts to participate in such studies.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-19-01.

A phase II study of bevacizumab in combination with vinorelbine and trastuzumab in HER2-positive metastatic breast cancer

We aimed to evaluate the efficacy and feasibility of combining trastuzumab/vinorelbine with bevacizumab in patients with first-or second-line HER2-positive, metastatic breast cancer (MBC). Eligible patients had HER2-positive measureable MBC, with no more than one prior line of chemotherapy, and were treated with trastuzumab (4 mg/kg × 2 mg/kg weekly thereafter), vinorelbine (25 mg/m(2) weekly), and bevacizumab (10 mg/kg every 2 weeks). Co-primary endpoints were (a) the proportion of patients alive and progression-free at 1 year and (b) safety profile/feasibility. Feasibility was defined as a rate of grade 3/4 non-hematologic toxicity attributable to protocol-based therapy <20 %. Twenty-nine patients were enrolled (n = 22 first-line, n = 7 second-line). Median age was 48 years (range 37-68). The median number of cycles received was 8 (1-23) and median duration on treatment was 7.4 months (range 1-22). The study was closed early due to higher-than-expected rates of grade 3/4 non-hematologic toxicities, with 50 events in 20 patients. A total of six patients (21 %) were taken off study for treatment-related toxicity. Most common treatment-related toxicities included fatigue (n = 7), febrile neutropenia (n = 4), and headache (n = 3). At 1 year, 8/22 first-line (36 %) and 2/7 second-line (29 %) patients were alive and progression-free. Median PFS was 9.9 months and 7.8 months in the first- and second-line cohorts, respectively. Objective responses were observed in 16/22 (73 %) and 5/7 (71 %) patients in the first- and second-line settings. Although the combination of vinorelbine, trastuzumab, and bevacizumab showed notable activity in HER2-positive MBC, the proportion of first-line patients alive and progression-free at 1 year was deemed unlikely to reach the pre-defined threshold for declaring success. Additionally, unacceptable toxicity was observed, at rates greater than previously reported with vinorelbine/trastuzumab or vinorelbine/bevacizumab doublet combinations.

Incidence and risk of central nervous system metastases as site of first recurrence in patients with HER2-positive breast cancer treated with adjuvant trastuzumab

BACKGROUND

Central nervous system (CNS) disease as the site of first relapse after exposure to adjuvant trastuzumab has been reported. We carried out comprehensive meta-analysis to determine the risk of CNS metastases as the first site of recurrence in patients with HER2-positive breast cancer who received adjuvant trastuzumab.

METHODS

Eligible studies include randomized trials of adjuvant trastuzumab administered for 1 year to patients with HER2-positive breast cancer who reported CNS metastases as first site of disease recurrence. Statistical analyses were conducted to calculate the incidence, relative risk (RR), and 95% confidence intervals (CIs) using fixed-effects inverse variance and random-effects models.

RESULTS

A total of 9020 patients were included. The incidence of CNS metastases as first site of disease recurrence in HER2-positive patients receiving adjuvant trastuzumab was 2.56% (95% CI 2.07% to 3.01%) compared with 1.94% (95% CI 1.54% to 2.38%) in HER2-positive patients who did not receive adjuvant trastuzumab. The RR of the CNS as first site of relapse in trastuzumab-treated patients was 1.35 (95% CI 1.02-1.78, P = 0.038) compared with control arms without trastuzumab therapy. The ratio of CNS metastases to total number of recurrence events was 16.94% (95% CI 10.85% to 24.07%) and 8.33% (95% CI 6.49% to 10.86%) for the trastuzumab-treated and control groups, respectively. No statistically significant differences were found based on trastuzumab schedule or median follow-up time. No evidence of publication bias was observed.

CONCLUSIONS

Adjuvant trastuzumab is associated with a significant increased risk of CNS metastases as the site of first recurrence in HER2-positive breast cancer patients.

Human epidermal growth factor receptor-2-positive breast cancer: does estrogen receptor status define two distinct subtypes?

BACKGROUND

Human epidermal growth factor receptor-2 (HER2) overexpression occurs in ∼20% of breast cancers and has historically been associated with decreased survival. Despite substantial improvements in clinical outcomes, particularly with the emergence of HER2-targeted therapy, a substantial minority of patients still relapses, and progression is inevitable in metastatic disease. Accumulating data indicate that HER2-positive disease is itself a heterogeneous entity.

METHODS AND RESULTS

In this article, we qualitatively review the data supporting the classification of HER2-positive disease as at least two separate entities, distinguished by estrogen receptor (ER) status. We summarize differences in clinical outcomes, including response to neoadjuvant therapy, timing and patterns of dissemination, efficacy of therapy in the metastatic setting and survival outcomes.

CONCLUSIONS

The collective data are sufficiently strong at this point to propose that ER status defines two distinct subtypes within HER2-positive breast cancer, and we highlight the implications of this knowledge in future research, including understanding of the basic biology of HER2-positive breast cancer and the design of future clinical trials.

Abstract P2-16-04: Attitudes of metastatic breast cancer patients towards research biopsies

Background: In the era of molecularly targeted therapy, developing an understanding of the molecular basis of cancer is a principal or secondary goal of many research studies. For this reason, studies collecting tissue for research purposes are increasingly common. Understanding patients' attitudes towards research biopsies may lead to improvement in accrual to research biopsy studies.

Methods: Patients with metastatic breast cancer from two academic and two community hospitals completed a self-administered paper survey consisting of 29 questions in clinic to evaluate their willingness to consider providing additional biopsies (additional biopsy performed with a clinically indicated biopsy) and research purposes only biopsies (RPOB) (research biopsy performed as a stand alone procedure).

Results: 160 patients (n = 80 academic, n=80 community) completed the survey, with a response rate of 98%. As expected, demographic variables differed between sites, with patients from academic sites likely to be younger (p = 0.01), more educated (p = 0.002), employed (p = 0.01), have prior trial participation (P &lt;0.001) and have a longer travel time (P &lt;0.0001). 64 (80%) academic patients and 51 (64%) community patients would definitely or probably consider additional biopsies. 42 (53%) academic patients and 40 (50%) community patients would consider RPOB.

In univariate analyses of patients' willingness to have additional biopsies, patients in academic sites were more likely to agree to additional biopsies than those at community sites (RR = 1.2, 95% CI 1.0–1.5, p = 0.03). Statistically significant differences based on demographic characteristics such as age, education, marital status, prior trial participation, number of prior biopsies, and travel time were not observed.

For RPOB, patients having had more prior biopsies were less likely to consider research biopsies (RR = 0.6, 95% CI 0.4–1.0, p = 0.03). The following variables did not reach statistical significance: type of practice, age, education, marital status, prior trial participation, and travel time.

Patients' willingness in both academic and community sites to consider RPOB declined with more invasive biopsies. Although differences were observed, none were statistically significant between academic and community; skin (56%, 65%), bone marrow (30%, 27%), breast (43%, 49%) or liver (24%, 19%).

Of the 13/160 (8%) patients who would not consider additional biopsies, the most common reasons cited included pain or discomfort (n = 8/13, 62%), risk of biopsy (n = 8/13, 62%) and anxiety related to the biopsy (n = 6/13, 46%). Of the 37/160 (23%) patients who would not consider RPOB, the most common reasons cited included pain or discomfort (n = 23/37, 62%), risk of biopsy (n = 15/37, 41%) and inconvenience of the procedure to the patient (n = 13/37, 35%).

Conclusions: The majority of patients in this study indicated they would consider research biopsies, with a larger proportion willing to consider additional biopsies; patients seen at academic hospitals were more likely to consider additional biopsies compared to those seen at community hospitals. Breast cancer patients' willingness to undergo research biopsies may be higher than generally expected by clinicians and may not be the primary barrier to obtaining research biopsies.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-16-04.

Abstract P6-08-03: Informational needs and psychosocial assessment of patients in their first year after metastatic breast cancer diagnosis

Background: Psychosocial distress is common after a diagnosis of breast cancer. Little is known about the informational needs and the psychosocial adjustment of patients diagnosed with metastatic breast cancer (MBC) within the first year of their diagnosis.

Methods: Patients with MBC from a single academic institution completed a cross-sectional self-administered paper survey. The survey included demographics, the Medical Outcomes Study Short Form-36 (SF-36), the Hospital Anxiety and Depression Scale (HADS), and Toronto Informational Needs Questionnaire-Breast Cancer (TINQ). Medical history was obtained by chart review. The Spearman correlation coefficient assessed the relationship between TINQ and the following: age at MBC diagnosis, disease free interval (DFI), time between survey completion and MBC diagnosis, number of lines of therapy, and HADS.

Results: Fifty-two (90%, 50F 2M) patients completed the survey. Median age at MBC diagnosis was 52 yrs (range 22–81). Thirty-nine (75%) patients had completed college, 92% were Caucasian. Median time between MBC diagnosis and survey completion was 6 months (range 1–12). Sixteen (31%) patients had de novo stage 4 disease. At time of survey completion, 36 (69%) patients were on 1st line therapy with some patients were receiving their 4th line of therapy. SF-36 scores were lower in all 8 subscales compared to the general population. In particular, role limitations due to physical health (Norm-based transformation mean score 39.3, SD=12.1), social functioning (Mean 41.8, SD=12.7), role limitations due to emotional problems (Mean 43.3, SD=13.3), vitality (Mean 44.1, SD=10.8) and general health (Mean 44.3, SD=12.1) were diminished. The Physical and Mental Component Summary norm-based transformation scores were 43.2 (SD = 11.7) and 45.4 (SD = 11.3) respectively.9/48 (19%) patients met criteria for anxiety, and 4/48 (8%) patients met criteria for depression by HADS criteria (scores &gt; 11). TINQ scores range from 51 to 255, with 35/52 (69%) having a total score &gt; 200, suggesting high informational need. Of the 5 subscales, treatment information was most important, followed by information about disease, physical care, psychosocial needs and investigative tests. The most important informational issues for patients were: if there was cancer anywhere else in their body (Mean score 4.78), how to deal with side effects (Score 4.78), and if there were ways to prevent treatment side effects (Score 4.77), with a score of 5=extremely important, and 1= not important.

Only DFI correlated with TINQ (Spearman coefficient −0.413, p = 0.011), with patients who had a shorter DFI having greater informational needs. Age at MBC diagnosis, time of completion of survey, number of lines and HADS were not significant.

Conclusion: Based on this study, patients with recently diagnosed MBC have high informational needs and poor psychosocial adjustment. The overall quality of life appears to be worse in this population of patients compared to the general population. There is also a subset of patients who are dealing with significant anxiety and depression. Additional research, education, and supportive care services aimed at meeting the informational and psychosocial needs of women living with MBC are warranted.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-08-03.

Abstract P5-18-03: Clinicopathological features among patients with HER2-positive breast cancer with prolonged response to trastuzumab based therapy

Background: HER2-positivity is a predictor of benefit from trastuzumab (TRZ), but fails to depict the observed interpatient variability in terms of treatment (tx) duration. In this study we described the relationship between clinicopathological features and TRZ tx duration.

Methods: A retrospective consecutive series of 343 HER2+ breast cancer (BC) patients (pts) treated with TRZ at the Dana-Farber Cancer Institute from 1999–2008 was identified. 139 pts treated with 1st line TRZ-based tx were selected for analysis. Pts who received any non-TRZ prior tx for metastatic disease were excluded. TRZ tx duration was defined as time from start of 1st line therapy to the 1st day of 2nd line therapy or death. Central nervous system (CNS) progression with TRZ maintenance was not considered change of tx. Pts were divided equally into 3 groups based on the duration of 1st line tx distribution. Short-term responders (STR) were on the 1st line tx for &lt;7 months (m), intermediate responders (IR) 7–15m and long responders (LTR) for &gt;15m. An additional group of extremely LTR (ELTR) was defined as being in the 90th percentile of tx duration (&gt;37m). Descriptive analysis was performed; fisher exact test, Kruskal-Wallis and logistic regression methods were used to compare groups.

Results: Median follow-up time since metastatic diagnosis was 4 years (y) (range 0–11). Median age at diagnosis was 47y (22–83), 25% of stage I-III pts at diagnosis received adjuvant/neoadjuvant TRZ. The median disease free interval (DFI) was 20m (0–172), median number of metastatic sites was 2(1–5), 68% of pts had visceral disease. Median duration of 1st line tx was 10m (2–105). TRZ was given with CT in 86%, hormone tx in 6% and as monotherapy in 9%. 25% of pts developed CNS progression and continued tx. There were only small absolute differences for clinicopathological characteristics among STR, IR and LTR.

Responses to subsequent anti-HER2 therapy after treatment with trastuzumab-DM1 in women with HER2-positive metastatic breast cancer

BACKGROUND

Women with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) can respond to multiple lines of anti-HER2 therapy. It is unknown whether these patients will derive further clinical benefit following treatment with trastuzumab-MCC-DM1 (T-DM1).

PATIENTS AND METHODS

We retrospectively identified HER2-positive MBC patients treated with T-DM1 and characterized outcomes during subsequent lines of anti-HER2 therapy. Response was determined by a blinded radiology review. Time-dependent analyses were carried out using Kaplan-Meier estimates.

RESULTS

We identified 23 patients treated with single-agent T-DM1 and report on the 20 patients who discontinued protocol therapy. All patients received trastuzumab-based metastatic therapy before initiation of T-DM1 [median 7 regimens (range 3-14)]. Of these 20 patients, 75% (15 of 20) received further therapy with or without anti-HER2 agents after discontinuing T-DM1. Partial response to either first- or second-subsequent line(s) of therapy was seen in 5 of 15 (33%) treated patients, including 33% (4 of 12) who received a regimen containing trastuzumab and/or lapatinib. Median durations of therapy to first- and second-subsequent regimens after T-DM1 were 5.5 and 6.4 months, respectively.

CONCLUSIONS

In heavily pretreated HER2-positive MBC patients, prior exposure to T-DM1 does not exhaust the potential benefit of ongoing anti-HER2 therapy with trastuzumab- and/or lapatinib-based regimens.

P5-01-13: High Levels of Nuclear Heat Shock Factor 1 (HSF1) Are Associated with Poor Prognosis in Breast Cancer: Results from the Nurses' Health Study

Purpose: Heat shock factor 1 (HSF1) is the master transcriptional regulator of the cellular response to heat and a wide variety of other stressors. We previously reported that HSF1 promotes the survival and proliferation of malignant cells. At this time, however, the clinical and prognostic significance of HSF1 in cancer is unknown.

Patients and methods: Breast cancer samples from 1,841 participants in the Nurses’ Health Study (NHS) were scored for levels of nuclear HSF1. Associations of HSF1 status with clinical parameters and survival outcomes were investigated by Kaplan-Meier analysis and Cox proportional hazard models. The associations were further delineated by Kaplan-Meier analysis using publicly available mRNA expression data.

Results: Nuclear HSF1 levels were elevated in ∼80% of in situ and invasive breast carcinomas. In invasive carcinomas, HSF1 expression was associated with high histologic grade, larger tumor size, and nodal involvement at diagnosis (P&lt;0.0001). Overall, in multivariate analysis, high-HSF1 levels were associated with increased breast cancer-specific mortality (HR, 1.62; 95% CI, 1.21−2.17). This association was seen in the ER-positive population (HR, 2.10; 95% CI, 1.25−2.47), even in early-stage lymph node negative cases (HR, 1.98; 95% CI, 1.17−3.33). In public expression profiling data, high-HSF1 mRNA levels were also associated with an increase in ER-positive breast cancer-specific mortality.

Conclusions: Increased HSF1 is associated with reduced survival in breast cancer. The findings indicate that HSF1 should be evaluated prospectively as an independent prognostic indicator in ER-positive breast cancer and that HSF1 may provide a useful therapeutic target.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-01-13.

P2-09-07: Metabolic Response by FDG-PET in Patients (pts) Receiving Trastuzumab (T) and Lapatinib (L) for HER2+ Metastatic Breast Cancer (MBC): Correlative Analysis of TBCRC 003

Background

We evaluated the safety and efficacy of L+T in pts with 0–2 prior lines of chemotherapy (CT) for HER2+ MBC. In the context of this phase II trial, we evaluated metabolic response by FDG-PET and explored the relationship between metabolic response and clinical outcomes.

Methods: Pts with measurable, HER2+ MBC were eligible. Cohort 1: No prior T, L, or CT +T for MBC, and &gt;1 yr from adjuvant T, if received. Cohort 2: 1–2 prior lines of CT for MBC, including T, or relapse within 1 yr of adjuvant T. Pts received L 1,000 mg QD + T (2 mg/kg weekly or 6 mg/kg Q3W). Staging studies were done with CT or MRI at baseline (BL) and every 2 cycles (1 cycle=4 weeks [wks]). Objective response was assessed by local investigator according to RECIST 1.0. FDG-PET/CT was performed at BL, Wk 1, and Wk 8 per NCI guidelines. Central quality assurance, review, and analysis were performed on FDG-PET studies. Up to 5 target lesions were identified on BL FDG-PET images based on hypermetabolic uptake. Percent change in the summed maximum standardized uptake value (SUVmax) of target lesions was calculated at Wk 1 or Wk 8, compared to BL. Metabolic response was assessed according to EORTC criteria for % change in SUVmax (progressive disease [PD]: ≥25% increase; partial response [PR]: ≥25% decrease; stable disease [SD]: &lt;25% change). Metabolic response at Wk 1 was compared to Wk 8 as well as to clinical outcome, including objective response, clinical benefit, and progression-free survival (PFS).

Results: 87 pts were registered to the study. Of these, one pt did not begin protocol therapy and one pt did not have MBC on further testing, and are not included. 81/85 pts had FDG-PET data at Wk 1; 75/85 had data at Wk 8. Metabolic PR at Wk 1 was observed in 28/39 (72%) pts in Cohort 1 and 20/42 (48%) pts in Cohort 2. Metabolic PR at Wk 8 was observed in 27/34 (79%) pts in Cohort 1 and 18/41 (44%) pts in Cohort 2. Wk 1 and Wk 8 metabolic responses were similar. In cohort 1, 18/28 (64%) pts who achieved Wk 1 metabolic PR had clinical benefit by RECIST. Of pts with Wk 1 metabolic SD, 2/9 (22%) had clinical benefit. In cohort 2, 9/20 (45%) pts who achieved Wk 1 metabolic PR had clinical benefit; 5/22 (23%) who achieved Week 1 metabolic SD had clinical benefit. Exploratory analysis of progression-free survival (PFS) showed that pts in Cohort 1 who achieved Wk 1 metabolic PR experienced a median PFS of 9.3 months ([mos]; 95% CI 5.6−22.3); for pts with metabolic SD, median PFS was 1.9 mos (95% CI 0.8−5.5). For pts in Cohort 2, Wk 1 metabolic PR was associated with median PFS of 5.6 mos (95% CI 3.7−7.8), whereas for pts with metabolic SD, median PFS was 3.7 mos (95% CI 1.8−5.5).

Conclusions: L+T is associated with a high rate of early and sustained metabolic response by FDG-PET. Exploratory analyses suggest that metabolic PR may be associated with clinical benefit and longer PFS.

Abstract P3-14-08: Responses to Subsequent Anti-HER2 Therapy after Treatment with Trastuzumab-DM1 in Women with HER2-Positive Metastatic Breast Cancer

Background: Women with HER2-positive metastatic breast cancer (MBC) can have clinical responses to multiple lines of anti-HER2 therapy. However, it is unknown whether these patients will derive further clinical benefit following treatment with the novel antibody-drug conjugate trastuzumab-MCC-DM1 (T-DM1), which has significant activity in trastuzumab-refractory breast cancer.

Methods: We retrospectively identified patients treated with T-DM1 monotherapy on clinical trials for HER2-positive MBC at Dana-Farber Cancer Institute and characterized clinical outcomes during subsequent lines of anti-HER2 therapy. Response was determined by an independent and blinded radiology review using modified RECIST 1.1 criteria without confirmatory scans; patients without radiologic assessment were considered non-responders. Duration of therapy was defined from initiation of therapy until treatment discontinuation, and for patients continuing on therapy, times were censored at date of last visit; analysis was performed using Kaplan-Meier estimates.

Results: We identified 23 patients treated on protocol-based therapy with single-agent TDM-1 and report on the 20 patients who had discontinued protocol, and hence, T-DM1 therapy. All patients received trastuzumab in the metastatic setting prior to initiation of T-DM1, with a median number of 6 (range 1-14) prior regimens. Most (75%) were taken off study secondary to progressive disease and the remainder discontinued therapy for toxicity. Of these 20 patients, 75% (15 of 20) received further therapy with or without anti-HER2 agents after concluding T-DM1; reasons for not receiving additional treatment after T-DM1 include death (3) and interruption of therapy due to physician or patient request (2). The majority (12 of 15; 80%) of patients treated beyond T-DM1 received a regimen containing either trastuzumab and/or lapatinib at some point during their course. Partial response to either first-or second-subsequent line(s) of therapy was seen in 5 of 15 (33%) treated patients, including 33% (4 of 12) who received a regimen containing trastuzumab and/or lapatinib (Figure 1). Three patients did not have radiographic assessments; however, all 3 demonstrated clinically stable disease (as determined by review of clinical data) to first treatment after T-DM1. Median duration of therapy to first-subsequent regimen after T-DM1 was 5.5 months. Of the 9 patients that received a second-subsequent regimen, the median duration of therapy to the second-subsequent treatment was 6.4 months.

Conclusions: In heavily pretreated HER2-positive MBC patients, prior exposure to T-DM1 does not exhaust the potential benefit of ongoing anti-HER2 therapy with trastuzumab and/or lapatinib-based regimens.

Maximum Decrease in Target Lesion Diameter

Clinicopathological features and sites of recurrence according to breast cancer subtype in the National Comprehensive Cancer Network (NCCN)

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Background: Gene expression profiling has defined multiple breast cancer subtypes which can approximated using standard immunohistochemical markers. Methods: We assessed clinicopathological features and sites of recurrence for patients (pts) presenting to NCCN sites with stage I-III breast cancer from Jan 2000 to Dec 2006 where estrogen receptor (ER), progesterone receptor (PR), and HER2 status were known. Tumors were grouped as luminal A (ER+ and/or PR+, and HER2-), HER2+ (any ER or PR, and HER2+), or triple-negative (ER-, PR-, and HER2-). Chi-square compared proportions across tumors; univariate logistic regression estimated risk of first site of recurrence. Results: 12,858 pts met inclusion criteria. Median follow-up from NCCN presentation was 3.2 years. Subtype distribution was: triple-negative (TN) 17%; HER2+ 18%; luminal A 66%. Compared to pts with luminal A and HER2+ tumors, TN were younger (p<0.0001), more likely African-American (p<0.0001) and overweight (p=0.0006). TN and HER2+ tumors were less often detected by screening mammography (TN, 28.9%; HER2+, 33.6%; luminal A, 48.4%) and less likely to present as T1 (TN, 46.5%; HER2+, 50.5%; luminal A, 67.0%) or diagnosed as stage I (TN, 32.6%; HER2+ 33.2%; luminal A, 49.4%) than luminal A (all p<0.0001). Rate of node positivity was lowest in TN (TN, 37.1%; HER2+, 44.9%; luminal A, 38.1%; p<0.0001). 83% of TN tumors were high grade; 93% were invasive ductal histology. Extensive intraductal component and lymphovascular invasion were more often associated with HER2+, compared to TN or luminal A (p<0.0001). Recurrences were recorded for 1,235 pts. Relative to luminal A, TN and HER2+ were more likely to experience lung (TN, odds ratio [OR] 2.27, 95% confidence interval [CI] 1.50, 3.43; p=0.0001; HER2+, OR 1.65, 95% CI 1.05, 2.60; p=0.03) and brain (TN, OR 5.32, 95% CI 2.85, 9.91; p<0.0001; HER2+, OR 5.53, 95% CI 2.93, 10.43; p<0.0001) as first site of recurrence; bone was less likely (TN, OR 0.23, 95% CI 0.16, 0.33; p<0.0001; HER2+, OR 0.38, 95% CI 0.28, 0.53; p<0.0001). Conclusions: Clinicopathological features and patterns of recurrence differed significantly by subtype and may inform the design of future clinical trials.

No significant financial relationships to disclose.