Response-guided neoadjuvant sacituzumab govitecan for localized triple-negative breast cancer: results from the NeoSTAR trial

BACKGROUND

Sacituzumab govitecan (SG), a novel antibody-drug conjugate (ADC) targeting TROP2, is approved for pre-treated metastatic triple-negative breast cancer (mTNBC). We conducted an investigator-initiated clinical trial evaluating neoadjuvant (NA) SG (NCT04230109), and report primary results.

PATIENTS AND METHODS

Participants with early-stage TNBC received NA SG for four cycles. The primary objective was to assess pathological complete response (pCR) rate in breast and lymph nodes (ypT0/isN0) to SG. Secondary objectives included overall response rate (ORR), safety, event-free survival (EFS), and predictive biomarkers. A response-guided approach was utilized, and subsequent systemic therapy decisions were at the discretion of the treating physician.

RESULTS

From July 2020 to August 2021, 50 participants were enrolled (median age = 48.5 years; 13 clinical stage I disease, 26 stage II, 11 stage III). Forty-nine (98%) completed four cycles of SG. Overall, the pCR rate with SG alone was 30% [n = 15, 95% confidence interval (CI) 18% to 45%]. The ORR per RECIST V1.1 after SG alone was 64% (n = 32/50, 95% CI 77% to 98%). Higher Ki-67 and tumor-infiltrating lymphocytes (TILs) were predictive of pCR to SG (P = 0.007 for Ki-67 and 0.002 for TILs), while baseline TROP2 expression was not (P = 0.440). Common adverse events were nausea (82%), fatigue (76%), alopecia (76%), neutropenia (44%), and rash (48%). With a median follow-up time of 18.9 months (95% CI 16.3-21.9 months), the 2-year EFS for all participants was 95%. Among participants with a pCR with SG (n = 15), the 2-year EFS was 100%.

CONCLUSIONS

In the first NA trial with an ADC in localized TNBC, SG demonstrated single-agent efficacy and feasibility of response-guided escalation/de-escalation. Further research on optimal duration of SG as well as NA combination strategies, including immunotherapy, are needed.

The immune profile of small HER2-positive breast cancers: a secondary analysis from the APT trial

BACKGROUND

Previous data suggest that the immune microenvironment plays a critical role in human epidermal growth factor receptor 2 (HER2) -positive breast cancer; however, there is little known about the immune profiles of small HER2-positive tumors. In this study, we aimed to characterize the immune microenvironment of small HER2-positive breast cancers included in the Adjuvant paclitaxel and trastuzumab for node-negative, HER2-positive breast cancer (APT) trial and to correlate the immune markers with pathological and molecular tumor characteristics.

PATIENTS AND METHODS

The APT trial was a multicenter, single-arm, phase II study of paclitaxel and trastuzumab in patients with node-negative HER2-positive breast cancer. The study included 406 patients with HER2-positive, node-negative breast cancer, measuring up to 3 cm. Exploratory analysis of tumor infiltrating lymphocytes (TIL), programmed death-ligand 1 (PD-L1) expression (by immunohistochemistry), and immune gene signatures using data generated by nCounter PanCancer Pathways Panel (NanoString Technologies, Seattle, WA), and their association with pathological and molecular characteristics was carried out.

RESULTS

Of the 406 patients, 328 (81%) had at least one immune assay carried out: 284 cases were evaluated for TIL, 266 for PD-L1, and 213 for immune gene signatures. High TIL (≥60%) were seen with greater frequency in hormone-receptor (HR) negative, histological grades 2 and 3, as well in HER2-enriched and basal-like tumors. Lower stromal PD-L1 (≤1%) expression was seen with greater frequency in HR-positive, histological grade 1, and in luminal tumors. Both TIL and stromal PD-L1 were positively correlated with 10 immune cell signatures, including Th1 and B cell signatures. Luminal B tumors were negatively correlated with those signatures. Significant correlation was seen among these immune markers; however, the magnitude of correlation did not indicate a monotonic relationship between them.

CONCLUSION

Immune profiles of small HER2-positive breast cancers differ according to HR status, histological grade, and molecular subtype. Further work is needed to explore the implication of these findings on disease outcome.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT00542451.

Effects of neratinib on health-related quality of life in women with HER2-positive early-stage breast cancer: longitudinal analyses from the randomized phase III ExteNET trial

BACKGROUND

We report longitudinal health-related quality-of-life (HRQoL) data from the international, randomized, double-blind, placebo-controlled phase III ExteNET study, which demonstrated an invasive disease-free survival benefit of extended adjuvant therapy with neratinib over placebo in human epidermal growth factor receptor-2-positive early-stage breast cancer.

PATIENTS AND METHODS

Women (N  = 2840) with early-stage HER2-positive breast cancer who had completed trastuzumab-based adjuvant therapy were randomly assigned to neratinib 240  mg/day or placebo for 12  months. HRQoL was an exploratory end point. Patients completed the Functional Assessment of Cancer Therapy-Breast (FACT-B) and EuroQol 5-Dimensions (EQ-5D) questionnaires at baseline and months 1, 3, 6, 9, and 12. Changes from baseline were compared using analysis of covariance with no imputation for missing values. Sensitivity analyses used alternative methods. Changes in HRQoL scores were regarded as clinically meaningful if they exceeded previously reported important differences (IDs).

RESULTS

Of the 2840 patients (intention-to-treat population), 2407 patients were evaluable for FACT-B (neratinib, N  = 1171; placebo, N  = 1236) and 2427 patients for EQ-5D (neratinib, N  = 1186; placebo, N  = 1241). Questionnaire completion rates exceeded 85%. Neratinib was associated with a decrease in global HRQoL scores at month 1 compared with placebo (adjusted mean differences: FACT-B total, -2.9 points; EQ-5D index, -0.02), after which between-group differences diminished at later time-points. Except for the FACT-B physical well-being (PWB) subscale at month 1; all between-group differences were less than reported IDs. The FACT-B breast cancer-specific subscale showed small improvements with neratinib at months 3-9, but all were less than IDs. Sensitivity analyses exploring missing data did not change the results.

CONCLUSIONS

Extended adjuvant neratinib was associated with a transient, reversible decrease in HRQoL during the first month of treatment, possibly linked to treatment-related diarrhea. With the exception of the PWB subscale at month 1, all neratinib-related HRQoL changes did not reach clinically meaningful thresholds. ClinicalTrials.gov: NCT00878709.

Abstract P2-13-01: Efficacy of neratinib in hormone receptor-positive patients who initiated treatment within 1 year of completing trastuzumab-based adjuvant therapy in HER2+ early-stage breast cancer: Subgroup analyses from the phase III ExteNET trial

Background: The international, randomized, placebo-controlled phase III ExteNET trial showed that 1 year (yr) of neratinib 240 mg/day after trastuzumab-based adjuvant therapy significantly improved invasive disease-free survival (iDFS) in 2840 patients with early-stage HER2+ breast cancer at 2 yr (hazard ratio 0.67; 95% CI 0.50–0.91; p=0.009) [Chan 2016] and 5 yr (hazard ratio 0.73; 95% CI 0.57-0.92; p=0.008) [Martin 2017]. A prespecified subgroup analysis by hormone receptor (HR) status suggested enhanced efficacy with neratinib in patients with HR+ (2-yr hazard ratio 0.51; 95% CI 0.33–0.77) vs. HR– tumors (2-yr hazard ratio 0.93; 95% CI 0.60–1.43). The efficacy of neratinib was also greater in patients who initiated treatment within 1 yr of prior trastuzumab compared with those who started neratinib later. The European Medicines Agency's Committee for Medicinal Products for Human Use recently recommended neratinib for use in patients with HR+ tumors who initiate treatment within 1 yr of completing trastuzumab-based adjuvant therapy. Subgroup analyses from ExteNET examining iDFS benefits in this patient population are presented here.

Methods: Patients with early-stage HER2+ breast cancer who completed trastuzumab-based (neo)adjuvant therapy were assigned to oral neratinib 240 mg/day or placebo for 1 yr. Randomization was stratified by HR status (determined locally before trial entry), nodal status, and trastuzumab regimen. Endocrine therapy was allowed in patients with HR+ disease. The primary endpoint, iDFS, was tested by 2-sided log-rank test and hazard ratios (95% CI) were estimated using Cox proportional hazards models. Kaplan-Meier methods were used to estimate iDFS rates. Secondary endpoints were DFS-DCIS, time to distant recurrence, distant DFS, and CNS recurrences. The primary analysis was conducted at 2 yr, and a sensitivity analysis conducted at 5 yr. Clinicaltrials.gov:NCT00878709.

Results: Of the 2840 patients (neratinib, n=1420; placebo, n=1420), 1631 (57%) had HR+ disease (neratinib, n=816; placebo, n=815). Most (93%) HR+ patients were receiving endocrine therapy at baseline. 1334 of 1631 (82%) patients with HR+ tumors were randomized to start neratinib within 1 yr of last trastuzumab dose (neratinib, n=670; placebo, n=664). iDFS benefits from neratinib in this population are shown in the table. Secondary endpoints were also improved with neratinib vs. placebo in this population. Safety data in this subset will be presented at the meeting.

Table. iDFS in patients with an interval between last trastuzumab dose and randomization of ≤1 yr

 HR+ population (N=1334)ITT population (N=2297)  Hazard ratiob  Hazard ratiob  Δ, %a(95% CI)P-valueΔ, %a(95% CI)P-value2-yr analysisc+4.50.490.002+2.90.630.006  (0.30–0.78)  (0.45–0.88) 5-yr analysisd+5.10.580.002+3.20.700.006  (0.41–0.82)  (0.54–0.90) aDifference in iDFS rates between neratinib vs. placebo; bNeratinib vs. placebo; cData cut-off: July 2014; dData cut-off: March 2017

Conclusions: Neratinib may have enhanced and sustained efficacy in patients with HR+ disease who initiate treatment within 1 yr of trastuzumab-based adjuvant therapy.

Citation Format: Gnant M, Martin M, Holmes F-A, Jackisch C, Chia SK, Iwata H, Moy B, Martinez N, Mansi J, Morales S, Ruiz-Borrego M, von Minckwitz G, Buyse M, Delaloge S, Bhandari M, Murias Rosales A, Galeano T, Fujita T, Luczak A, Barrios CH, Saura C, Rugo HS, Chien J, Johnston SR, Spencer M, Xu F, Barnett B, Chan A, Ejlertsen B. Efficacy of neratinib in hormone receptor-positive patients who initiated treatment within 1 year of completing trastuzumab-based adjuvant therapy in HER2+ early-stage breast cancer: Subgroup analyses from the phase III ExteNET trial [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 P2-13-01.

Abstract P4-08-08: Genomic progression, detected by circulating tumor DNA (ctDNA) sequencing, as an early predictor of disease progression in metastatic breast cancer (MBC)

Background: The availability of multiple therapies has transformed the landscape of MBC, but also brought the challenge of selecting the right therapy for an individual patient. Furthermore, in patients with Hormone Receptor positive (HR+) breast cancer who have bone metastases only it may be difficult to assess effectiveness of therapy via imaging. Peripheral ctDNA detection and analysis by next-generation sequencing (NGS) has gained popularity in cancer diagnosis and therapeutics due to its relative noninvasiveness, ease of use, and high sensitivity. Here, we explore the utility of ctDNA change as a predictor for disease progression in MBC. We hypothesized that genomic progression is a harbinger of subsequent radiologic progression in patients with MBC.

Methods: We analyzed change from pre-treatment (baseline) to on-treatment ctDNA mutant allele fraction (MAF) among patients with MBC. Patients receiving standard-of-care therapies or investigational agents on clinical trials at our institution were included. All patients were followed from the date of baseline test until death or data cutoff (6/20/2018). All peripheral blood specimens were collected and analyzed between 1/7/2016 and 3/1/2018 via NGS (Guardant360®). Peripheral blood specimens were sequenced prior to initiation of a new therapeutic regimen (baseline) and subsequently at least once while on-treatment, on average 4-12 weeks later. All patients had a follow-up CT scan of chest, abdomen and pelvis 2-4 weeks after the on-treatment NGS. A priori, we defined genomic progression as increase in ctDNA total MAF of at least 20% from baseline. We utilized Cox regression analysis to identify whether genomic progression was a predictor of radiologic progression, adjusting for common prognostic variables.

Results: All patients (N= 77) were female, predominantly White (83.1%), and median age was 57 (range 32 to 77). Fifty one out of 77 patients (66.2%) were ER+, 5 HER2+, and 9 had triple negative breast cancer. The median MAF at baseline was 2.2% (range 0% - 61.7%). Common genomic alterations in ctDNA included PIK3CA, TP53, ESR1, AKT1, NF1. 27 out of 77 (35%) patients showed disease progression on the first subsequent CT scan, while 59 out of 77 (76.6%) progressed during the follow up time. We found that an increase in ctDNA MAF of at least 20% was a strong predictor of disease progression (HR =2.46, CI [1.14-5.32], p=0.02), compared to those who had a MAF increase of less than 20% or a decrease in total MAF. In multi-variable analysis, adjusting for age, number of prior therapies, type of therapy, and visceral metastases, increase in ctDNA remained a significant predictor for subsequent disease progression (HR =3.84, CI [1.63-9.07], p=0.002). Subset results in patients with bone metastases only, and relative comparison of ctDNA with standard tumor markers will be presented at the meeting.

Conclusions: Genomic progression, identified by an increase in ctDNA MAF, is potentially an early predictor of subsequent disease progression in patients with MBC. Further research is needed to prospectively evaluate the clinical utility of ctDNA change as a surrogate marker in guiding treatment decision-making for patients with MBC.

Citation Format: Velimirovic M, Juric D, Niemierko A, Spring LM, Vidula N, Malvarosa G, Yuen M, Moy B, Isakoff SJ, Ellisen LW, Bardia A. Genomic progression, detected by circulating tumor DNA (ctDNA) sequencing, as an early predictor of disease progression in metastatic breast cancer (MBC) [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 P4-08-08.

Abstract P4-01-06: Comparison of tumor genotyping and cell-free circulating tumor DNA sequencing in metastatic breast cancer patients and their utility in the selection of matched therapy

Background: Oncogenic mutations are potential targets for therapeutic intervention in metastatic breast cancer (MBC). While tumor genotyping (TG) has been viewed as the gold standard for identifying oncogenic mutations, cell-free circulating tumor DNA (cfDNA) is emerging as an alternate technique. We previously reported the selection of matched therapy targeted to an actionable mutation based on either TG or cfDNA testing (Vidula N, ASCO, 2018). Therefore, we are now comparing TG and cfDNA results in MBC patients undergoing both tests to examine their relative utility in the selection of matched therapy.

Methods: Patients with MBC at an academic institution who underwent both TG (Next Generation Sequencing/NGS, institutional platform, 104 gene assay) and cfDNA testing (NGS/Guardant360, 73 gene assay) between 1/2016-10/2017 were identified. A chart review was conducted to identify tumor subtype, demographics, treatment, TG and cfDNA results, and clinical outcomes. The relative utility of these tests in the selection of matched therapy was determined, and linked with clinical outcomes (progression-free survival and overall survival).

Results: Thirty patients who underwent both TG and cfDNA testing were identified. The median age was 60 years, the majority (97%) had hormone receptor (HR) positive/HER2 negative disease, and most patients had recurrent disease (83.3%) at MBC diagnosis. The median number of therapies prior to obtaining either test was 1 (cfDNA range 0-9, TG range 0-8). The majority had simultaneous cfDNA and tumor genotyping testing (83.3%) versus sequential testing (16.7%). Twenty-four (80%) patients had actionable mutations detected by cfDNA compared to 19 (63.3%) patients with actionable mutations detected by TG. The median number of actionable mutations detected by cfDNA was 2 (range 0-11) compared with a median of 1 (range 0-4) detected by TG. Failure of TG occurred in 2 of 30 patients (6.7%) but no test failures were seen with cfDNA. Eleven of 30 patients (36.7%) had ≥ 1 concordant mutation via cfDNA and TG. Altogether, 12 out of 30 (40%) patients received matched therapy, 5 of which were based on cfDNA actionable mutations alone (ESR1, ERBB2, CCND1, and PIK3CA), and 7 based on cfDNA and TG results (ESR1, PIK3CA, STK11, and BRCA). Twelve of 24 (50%) patients with actionable cfDNA mutations went on to receive matched therapy compared with 7 of 19 (36.8%) patients with actionable TG results. Matched therapies included SERDs, inhibitors of CDK 4/6, PI3K, mTOR, HER2 directed therapy, and DNA damaging chemotherapy. The impact of matched therapy on survival outcomes will be presented at the meeting.

Conclusions: In patients undergoing both TG and cfDNA testing, both tests identify a significant cohort of HR+ MBC patients with actionable mutations, with greater detection of actionable mutations by cfDNA. Greater application of matched therapy occurred via cfDNA, which independently informed the selection of matched therapies. Further research is needed to prospectively evaluate the clinical utility of blood based genotyping assays versus TG for patients with MBC.

Citation Format: Vidula N, Juric D, Niemierko A, Spring L, Moy B, Malvarosa G, Yuen M, Habin K, Shin J, Peppercorn J, Isakoff S, Ellisen L, Iafrate AJ, Bardia A. Comparison of tumor genotyping and cell-free circulating tumor DNA sequencing in metastatic breast cancer patients and their utility in the selection of matched therapy [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 P4-01-06.

Abstract P2-14-19: Surgical and long-term outcomes of patients receiving neoadjuvant pertuzumab-containing regimens for HER2-positive localized breast cancer

Background: The addition of pertuzumab to trastuzumab and chemotherapy significantly improves the pathologic complete response (pCR) rate in HER2+ localized breast cancer in the preoperative setting. Although many patients are converted to breast conserving therapy (BCT) candidates by neoadjuvant HER2-directed therapy, a significant proportion opt for a mastectomy for various reasons. Among mastectomy procedures, nipple sparing mastectomy (NSM) is frequently chosen instead of non-nipple sparing mastectomy (NNSM). In this study, we evaluated the surgical and long-term outcomes of HER2+ patients receiving neoadjuvant pertuzumab-containing regimens.

Methods: We performed a retrospective review of localized breast cancer patients treated with neoadjuvant pertuzumab-containing regimens from 2011 to 2016, who underwent BCT or mastectomy at an academic institution and two community-based practices. Disease characteristics, treatment regimens, surgical outcomes, and recurrence data were extracted from the electronic medical records.

Results: Among 90 patients with stage II-III HER2+ breast cancer, 45 received AC-THP (50.0%), 26 received THP (with adjuvant AC) (29.0%), and 19 received TCHP (21.0%). The majority of patients had grade 3 tumors (61.1%), clinical stage II disease (80.0%), invasive ductal carcinoma (86.7%), and ER+ disease (65.6%). Thirty-seven (41.0%) patients underwent BCT and 53 (59.0%) patients underwent mastectomy. Among the mastectomy patients, 38 (71.7%) patients underwent bilateral mastectomies, specifically 33 (62.0%) patients underwent a NSM and 20 (38.0%) patients underwent a NNSM. The type of surgery that patients underwent stratified by type of neoadjuvant regimen is outlined in the Table 1 below. Most patients who underwent BCT and mastectomy received radiation, including 36 (97.3%) BCT, 24 (72.7%) NSM, and 18 (95.0%) NNSM. Over a median follow-up period of 33 months, 6 patients (6.7%) had recurrences with 2 (2.2%) local recurrences and 4 (4.4%) distant recurrences. The 2 local recurrences occurred in one patient who underwent BCT and one patient who underwent NNSM followed by post-mastectomy radiation.

Conclusions: Among mastectomy patients, NSM was more commonly pursued than NNSM. Rates of local recurrence following pertuzumab-containing regimens for HER2-positive localized breast cancer were low overall, regardless of the type of surgery. Data on plastic surgery approaches and complication rates will be presented at the meeting.

Table 1.Type of surgery in patients receiving neoadjuvant HER2-directed therapy. AC-THP (N = 45)TCHP (N = 19)THP (N = 26)BCT46.7%47.4%26.9%NNSM26.7%10.5%23.1%NSM26.7%42.1%50.0%

Citation Format: Haddad SA, Spring LM, Jimenez RB, Vidula N, Comander A, Shin JA, Coopey SB, Gadd MA, Hughes KS, Taghian A, Smith BL, Isakoff SJ, Moy B, Bardia A, Specht MC. Surgical and long-term outcomes of patients receiving neoadjuvant pertuzumab-containing regimens for HER2-positive localized 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 P2-14-19.

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 P2-02-18: Higher mutation burden and mutant allele fraction of circulating tumor DNA corresponds to worse progression free survival in metastatic breast cancer patients

Introduction: Genomic profiling of circulating tumor DNA (ctDNA) allows non-invasive monitoring of tumor genetic changes and molecular heterogeneity. In addition to actionable mutations, mutational landscape derived from ctDNA could provide a better representation of overall tumor burden and tumor heterogeneity, as well as potentially impact clinical outcomes. To evaluate this hypothesis, this study assessed the association of mutation burden and average mutant allele fraction (MAF) with tumor subtype, therapeutic response, and survival in patients with metastatic breast cancer.

Methods: Whole blood samples from patients with metastatic breast cancer were collected during clinic visits before start of a new therapy. Plasma-derived cell-free DNA underwent complete next-generation sequencing of 73 cancer-related genes with the Guardant360 test. Mutation burden was defined as the number of genes with mutations, and average MAF was calculated as the sum of the highest MAF for each mutated gene divided by the number of genes with mutations. Time to progression was measured from the date of new treatment initiation after circulating tumor DNA collection to the date of progression. Multivariate cox proportional hazard models assessed the association of mutation burden and average MAF with progression free survival (PFS), adjusted for age, receptor subtype (hormone receptor positive, HR+; human epidermal growth factor 2 positive, HER2+; triple negative breast cancer, TNBC), treatment subtype (chemotherapy vs. targeted therapy), and number of prior metastatic breast cancer therapies. A p value of 0.05 was considered statistically significant.

Results: The study population consisted of 158 women with metastatic breast cancer (108 HR+, 14 HER2+, 19 TNBC) with a median age of 59 years and a median of 2 prior metastatic breast cancer therapies. Median follow up time was 4.0 months, and median PFS was 15.7 months. Mutation burden was greater in triple negative compared to hormone receptor positive breast cancer (7.5 vs. 4.8, p = 0.02) but no different in patients with > 2 prior metastatic therapies vs. not (5.1 vs. 4.7, p = 0.60) and age >45 vs. not (5.0 vs. 3.9; p = 0.26). In univariate models, high mutation burden (> median of 2) and high MAF (> median of 1.4) were significantly associated with worse PFS (Table). These results were similar in effect size and significance when adjusted for age, receptor subtype, treatment subtype, and number of prior metastatic breast cancer therapies. Impact of mutation burden on response to specific therapies will be presented at the meeting.

VariableHazard Ratio95% Confidence Intervalp valueHigh mutation burden1.991.12-3.540.02High mutant allele fraction1.881.06-3.330.03

Conclusions: Higher ctDNA mutation burden and average MAF is associated with worse progression free survival and possibly reflects a more treatment refractory phenotype. Whether immunotherapy, alone or in combination, could influence the clinical outcomes in metastatic breast cancer patients with high ctDNA mutation burden is unclear and warrants additional research.

Citation Format: Keenan T, Juric D, Niemierko A, Spring L, Park H, Malvarosa G, Beeler M, Moy B, Ellisen L, Isakoff S, Bardia A. Higher mutation burden and mutant allele fraction of circulating tumor DNA corresponds to worse progression free survival in metastatic breast cancer patients [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 P2-02-18.

Abstract P1-13-05: Timing of initiation of neratinib after completion of trastuzumab-based adjuvant therapy in early-stage HER2+ breast cancer: Exploratory analyses from the phase III ExteNET trial

Background: The international, randomized, placebo-controlled phase III ExteNET trial showed that 1 year of neratinib after trastuzumab-based adjuvant therapy significantly improved 2-year invasive disease-free survival (iDFS) in early-stage HER2+ breast cancer (HR 0.67; 95% CI 0.50–0.91; p=0.009) [Chan et al. Lancet Oncol 2016]. The significant iDFS benefit with neratinib was maintained after a median of 5 years' follow-up (HR 0.73; 95% CI 0.57-0.92; p=0.008) [Martin et al. ESMO 2017]. We present exploratory analyses from the ExteNET trial examining the effects of the interval between completion of trastuzumab and randomization to commence neratinib on iDFS.

Methods: Women with early-stage HER2+ breast cancer were randomly assigned to oral neratinib 240 mg/day or placebo for 1 year after standard primary therapy and trastuzumab-based adjuvant therapy. Under the original study protocol, (neo)adjuvant trastuzumab was to be completed ≤24 months before randomization; this was revised to ≤12 months before randomization after the NCCTG-N9831/NSABP B-31 4-year analysis showed that the risk of relapse is greatest during the first 12 months after completing trastuzumab. Disease recurrences were collected prospectively during 1 and 2 years post-randomization, and from medical records during 3–5 years post-randomization. Patients randomized ≤12 months after completion of adjuvant trastuzumab were further separated to look at those who initiated neratinib ≤6 months of completing adjuvant trastuzumab. Primary endpoint: iDFS. HR (95% CI) estimated using Cox proportional-hazards models. Data cut-off: March 1, 2017. Clinicaltrials.gov: NCT00878709.

Results:The intention-to-treat population comprised 2840 patients (neratinib, n=1420; placebo, n=1420). Median time from last trastuzumab dose to randomization was 4.4 and 4.6 months in the neratinib and placebo groups, respectively. 81% of patients were randomized ≤12 months of completing trastuzumab. The effects of the interval between the last dose of trastuzumab and randomization/initiation of neratinib on iDFS after a median follow-up of 5.2 years are shown in the table.

  Estimated 5-year iDFS rate, % P-valueInterval from last dose of trastuzumab to randomizationnNeratinibPlaceboHR (95% CI)a(2-sided)≤6 months164190.085.40.62 (0.46–0.84)0.002≤12 monthsb229789.786.50.70 (0.54–0.90)0.006>12 monthsb54392.392.61.00 (0.51–1.94)0.992a. Neratinib vs placebo; b. Protocol-defined subgroups

Conclusions: In ExteNET, patients who initiated neratinib within 12 months of completing trastuzumab-based adjuvant therapy appeared to derive greater benefit from treatment than those who started neratinib later. Further, exploratory analyses suggest that the magnitude of benefit with neratinib is greater if initiated sooner (i.e. within 6 months of completing trastuzumab). Given the benefits of neratinib overall in those initiating treatment ≤12 months from the end of adjuvant trastuzumab, extended adjuvant treatment with neratinib should be initiated early following completion of trastuzumab.

Citation Format: Ejlertsen B, Chan A, Gnant M, von Minckwitz G, Delaloge S, Buyse M, O'Shaughnessy J, Mansi J, Moy B, Iwata H, Wong A, Ye Y, Means-Powell J, Hui R, Ruiz-Borrego M, Ruiz Simon A, Shen Z-Z, Holmes FA, Lesniewski-Kmak K, Martin M. Timing of initiation of neratinib after completion of trastuzumab-based adjuvant therapy in early-stage HER2+ breast cancer: Exploratory analyses from the phase III ExteNET trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-13-05.

Abstract P3-10-14: Clinical and economic burden of HER2-positive breast cancer recurrence in the US: A literature review

Background: Despite available treatment for early-stage breast cancer (BC), 15%-25% of patients with early-stage human epidermal growth factor receptor 2–positive (HER2+) BC eventually experience recurrence after initial treatment. The prognosis for women with HER2+ disease recurrence is poor. Most recurrences involve incurable metastatic disease. In the US, the total cost to society attributable to metastatic BC of any subtype was $12.2 billion accrued over 5 years, or $2.4 billion per year ($98,571 per patient-year). Treatment-related cost, 57% of total costs, was the largest contribution, with over $1.0 billion per year. The purpose of this study was to assess the clinical and economic burden of recurrence in patients with early-stage HER2+ BC.

Methods: We conducted two systematic literature reviews (SLRs) and one targeted literature review (TLR) in PubMed, Embase, and Cochrane databases. The SLRs (no publication date limit; clinical SLR conducted on November 8, 2016; economic SLR conducted on October 25, 2016) searched for randomized clinical trials of neratinib and other treatments and economic data (models, utility, resource use, and cost), and the TLR (publications published from January 2006 to September 2016) searched for burden-of-illness studies in early-stage HER2+ BC.

Results: A total of 4,708 abstracts (2,649 clinical SLR; 969 economic SLR; 1,090 TLR) were identified from all searches, and full-text review was conducted for 796 articles (507 clinical SLR; 151 economic SLR; 138 TLR). Of these, 159 (72 clinical SLR; 33 economic SLR; 54 TLR) followed protocol-specified criteria for inclusion. Based on clinical trials in the neoadjuvant and/or adjuvant setting, disease-free survival rates at 4 years ranged from 78% to 90%. HER2-targeting adjuvant regimens such as lapatinib added to trastuzumab and extending trastuzumab to 2 years have been unsuccessful in reducing the risk of recurrence. Women who had a recurrence, regardless of HER2 status, reported significantly poorer functioning on various quality of life (QoL) domains compared with women who remained disease free. All patients with early-stage BC, regardless of HER2 status, diagnosed with their first recurrence experienced cancer-related distress and no improvement in QoL (physical health and functioning) after 1 year. In the US, the total expected per-patient costs for all BC, regardless of HER2 status, over 10 years was $53,454 with metastatic recurrence, $61,601 with locoregional recurrence, and $61,188 with contralateral recurrence as compared with $42,005 (background costs) with no recurrence (2004 US $). The overall cost of recurrence in women with HER2+ BC in the US was estimated to be $240 million to $1.7 billion over the lifetimes of each 1-year cohort of 7,298 patients (2008 US $).

Conclusions: These results identified few studies on patients with early-stage HER2+ BC and suggest that future studies are warranted. Recurrence in women with HER2+ BC is associated with decreased QoL and high costs. After adjuvant therapy, there is still risk of recurrence, thus the clinical and economic burden remains. There is an unmet medical need in early-stage HER2+ BC, and new therapies are needed to reduce the risk of recurrence.

Citation Format: Masaquel C, Hurley D, Barnett B, Krieger T, Pearson I, Copley-Merriman C, Kaye JA, Moy B. Clinical and economic burden of HER2-positive breast cancer recurrence in the US: A literature review [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 P3-10-14.

Abstract PD1-13: Somatic BRCA mutation detection by circulating tumor DNA analysis in patients with metastatic breast cancer: Incidence and association with tumor genotyping results, germline BRCA mutation status, and clinical outcomes

Introduction:

BRCA mutations may impact patient outcomes, as well as chemotherapy response in patients with breast cancer (BC). While germline BRCA mutations have been well-studied, the incidence and clinical impact of somatic BRCA mutations have not been well-described. We evaluated the presence of BRCA mutations, and the association between somatic BRCA mutations with clinical outcomes in patients with metastatic breast cancer (MBC).

Methods:

We identified patients with MBC who underwent ctDNA testing by Guardant360 at our institution before the start of a new therapy. From this subset of patients, we subsequently identified those patients with circulating tumor DNA (ctDNA) BRCA 1 or 2 mutations. We conducted a retrospective review of medical and pathology records to identify tumor subtype, germline BRCA testing results, and tissue genotyping results based on institutional Snapshot-NGS genotyping assay. In addition, we conducted a multivariate analysis to evaluate the hazard ratio (HR) for the association between ctDNA BRCA mutation and progression free survival (PFS) adjusting for age, number of prior therapies, and type of therapy.

Results

Among patients with MBC (N = 178), 27 (15.2%) had BRCA alterations detected by ctDNA analysis. Among patients with ctDNA BRCA alterations, the median age at metastatic diagnosis was 53; 16/24 (66.6%) had hormone receptor (HR)+/HER2- BC, 5/24 (20.8%) had triple negative (TN) BC, 2/24 (8.3%) had HR-/HER2+ BC, and 1/24 (4.2%) had HR+/HER2+ BC. Of patients with ctDNA BRCA mutations, only a minority (16.7%) had BRCA alterations detected by genotyping of archival tumor, and only 1 (3.7%) had a germline BRCA mutation (BRCA 1). In multivariate analysis, patients with BRCA mutant tumors, had similar median PFS as compared to non-BRCA mutant breast cancer (HR: 1.17; p = 0.58). Overall survival analysis and impact of BRCA mutations on response to therapy, particularly DNA damaging agents, will be presented at the meeting.

Conclusions:

BRCA mutations by ctDNA are detectable in a significant proportion of MBC patients. Most BRCA mutations detected by ctDNA were not identified by genotyping of archival tissue, and were not associated with germline BRCA mutations, suggesting that somatic BRCA mutations may be detected by sensitive blood-based genotyping assays in patients who are not known BRCA carriers. The therapeutic impact of DNA damaging agents and PARP inhibitors in MBC patients with somatic BRCA alterations is not known and warrants additional research.

Citation Format: Vidula N, Isakoff SJ, Niemierko A, Malvarosa G, Park H, Abraham E, Spring L, Peppercorn J, Moy B, Ellisen LW, Juric D, Bardia A. Somatic BRCA mutation detection by circulating tumor DNA analysis in patients with metastatic breast cancer: Incidence and association with tumor genotyping results, germline BRCA mutation status, and clinical outcomes [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 PD1-13.

Abstract P1-13-03: Effects of neratinib after trastuzumab-based adjuvant therapy in hormone receptor-positive HER2+ early-stage breast cancer: Exploratory analyses from the phase III ExteNET trial

Background: The international, randomized, placebo-controlled phase III ExteNET trial showed that a 1-year course of neratinib after trastuzumab-based adjuvant therapy significantly improved 2-year invasive disease-free survival (iDFS) in patients with early-stage HER2+ breast cancer (BC) (hazard ratio 0.67; 95% CI 0.50–0.91; p=0.009) [Chan et al. Lancet Oncol 2016]. The significant iDFS benefit with neratinib was maintained after a median 5 years' follow-up (hazard ratio 0.73; 95% CI 0.57-0.92; p=0.008) [Martin et al. ESMO 2017]. At both time-points, marked benefit with neratinib was evident in patients with hormone receptor (HR)+ tumors, whereas in patients with HR– disease, initial improvements with neratinib diminished after completing treatment. We report exploratory analyses from the ExteNET trial done to better characterize the effects of neratinib in the HR+ subgroup.

Methods: Patients with early-stage HER2+ BC were randomly assigned to oral neratinib 240 mg/day or placebo for 1 year after standard primary therapy and trastuzumab-based adjuvant therapy. Randomization was stratified by HR status (locally assessed), nodal status, and trastuzumab regimen. Adjuvant endocrine therapy was recommended for patients with HR+ disease. Data concerning disease recurrences were collected prospectively during year 1-2 post-randomization, and from medical records during year 3–5 post-randomization. Primary endpoint: iDFS. Secondary endpoints: DFS including ductal carcinoma in situ (DFS-DCIS); time to distant recurrence (TTDR); distant DFS (DDFS); cumulative incidence of central nervous system (CNS) recurrences; overall survival (OS). Hazard ratios (95% CI) were estimated using Cox proportional-hazards models. Data cut-off: March 2017. Clinicaltrials.gov: NCT00878709.

Results: 2840 patients were randomized (neratinib, n=1420; placebo, n=1420); 1631 (57%) patients had HR+ tumors (neratinib, n=816; placebo, n=815). 93% and 94% of HR+ patients in the neratinib and placebo groups, respectively, were receiving adjuvant endocrine therapy at baseline. Efficacy outcomes in the HR+ cohort after a median follow-up of 5.2 years are shown in the table. In subgroup analyses of the HR+ cohort, hazard ratios for iDFS were 0.49 in centrally confirmed HER2+ patients (n=951), and 0.58 in patients who had completed prior trastuzumab ≤12 months before randomization (n=1334). CNS recurrence and OS data are not yet mature.

 Updated 2-year analysis5-year analysis  Hazard ratiobP-value Hazard ratiobP-value Δ, %a(95% CI)(2 sided)Δ, %a(95% CI)(2 sided)iDFS4.10.49 (0.31–0.75)0.0014.40.60 (0.43–0.83)0.002DFS-DCIS4.80.45 (0.29–0.69)<0.0015.10.57 (0.42–0.79)<0.001DDFS3.10.52 (0.32–0.84)0.0084.00.60 (0.42–0.85)0.004TTDR2.90.52 (0.31–0.85)0.013.80.61 (0.42–0.86)0.006a. Difference in event rates between neratinib vs placebo; b. Neratinib vs placebo

Conclusions: Neratinib was associated with an absolute iDFS benefit of 4.4% in patients with HR+/HER2+ BC after 5 years' follow-up. HR/HER2 receptor cross-talk may underpin the notable effect of neratinib in patients with HR+ tumors when given in combination with endocrine therapy.

Citation Format: Chia SKL, Martin M, Iwata H, Moy B, Lalani AS, Holmes FA, Mansi J, von Minckwitz G, Buyse M, Delaloge S, Ejlertsen B, Yao B, Murias Rosales A, Hellerstedt B, Cold S, Inoue K, Shen Z-Z, Galeano T, Barrios CH, Chan A. Effects of neratinib after trastuzumab-based adjuvant therapy in hormone receptor-positive HER2+ early-stage breast cancer: Exploratory analyses from the phase III ExteNET trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-13-03.

Abstract P5-20-02: HER2 mutations detected by ctDNA in ER+/HER2- metastatic breast cancer patients: Incidence and impact on clinical outcomes

Background: While the human epidermal growth factor receptor 2 (HER2) gene has long been linked with the pathogenesis and prognosis of breast cancer, its significance has been recognized only when the receptor has been amplified. However, rare, but actionable, somatic mutations in HER2, without HER2 gene amplification, have been described in breast cancer based on molecular analysis of metastatic specimens (frequency ˜ 1%). Little is known about the incidence based on blood-based genotyping assays, as well as impact of HER2 mutations on clinical outcomes in patients with ER+/HER2- metastatic breast cancer (MBC).

Methods: We evaluated the presence of HER2 mutations based on routine tissue and blood-based genotyping assays, ordered by treating oncologists at our institution, for patients with estrogen receptor positive (ER+)/HER2 negative MBC. The tissue analysis was based on SNAPSHOT-NGS, an anchored multiplex polymerase chain reaction assay that detects single nucleotide variants (SNV) and insertions/deletions (indel), and the blood-based genotyping analysis was based on circulating tumor DNA (ctDNA) detection using the Guardant 360 panel, a next-generation sequencing (NGS) assay capable of detecting mutations with comparable sensitivity to SNAPSHOT. Patients with acquired HER2 mutations were identified, and multivariate analysis was performed to evaluate the hazard ratio (HR) for the association between HER2 mutations and progression free survival (PFS), adjusting for age and number of prior therapies.

Results: Among the ER+/HER2- MBC patients (N=118), 11% (N= 13) were found to have acquired HER2 mutation by ctDNA analysis, but no HER2 mutations were identified in any of patients based on tissue-based molecular analysis of archival specimens. Among patients with HER2 mutant, ER+/HER2- MBC, the median age at metastatic diagnosis was 57.34 (range 51.5-67.1) years, 7.7% had de-novo metastatic disease, and 30.8% had prior CDK 4/6 inhibitor therapy. In terms of outcomes, in the multivariate model, patients with HER2 mutant breast cancer had similar PFS when treated with endocrine and targeted therapy combination (HR = 0.24; p = 0.21), and trended towards worse PFS with chemotherapy (HR = 2.69; p = 0.06), as compared to non-HER2 mutant group, albeit duration of follow up was limited (median duration = 6.7 months). Of note, most of the detected HER2 mutations were activating or deleterious, but not all were clonal. Updated outcome data, including overall survival, will be presented at the meeting.

Conclusions: A much larger subset of patients with ER+/HER2- MBC have HER2 mutations detectable by ctDNA, but not by tissue, which highlights the need for blood-based biomarker monitoring for identification of actionable mutations, as well as the potential clinical utility in development of genotype driven trials for patients with HER2 mutant, ER+/HER2- MBC.

Citation Format: Medford A, Juric D, Niemierko A, Malvarosa G, Park H, Shellock M, Spring L, Moy B, Isakoff S, Ellisen L, Bardia A. HER2 mutations detected by ctDNA in ER+/HER2- metastatic breast cancer patients: Incidence and impact on clinical outcomes [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 P5-20-02.

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

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

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

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

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

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

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

Abstract P1-06-03: Serial evolution of hormone receptor status and mutational profile among patients with metastatic breast cancer

Introduction: Tumor heterogeneity presents a significant impediment to identifying appropriate treatments for patients. Genetic mutations and hormone receptors are frequently used as a guide for selecting appropriate targeted or hormonal therapies, however it is possible that these markers may change over time, leading to reduced effectiveness of these treatments. In this study, we review the results of serial and paired biopsies to identify receptor switch in estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status as well as to identify changes in clinically relevant mutations, including spatial and temporal heterogeneity.

Methods: We identified a total of 237 patients initially presenting with ER+/HER2 negative breast cancer and who had multiple biopsies during the course of their treatment, including at least one in the metastatic setting. ER, PR, and HER2 status for each of these serial biopsies was gathered from chart reviews. HER2 results by both IHC and FISH were collected. PIK3CA mutations were also assessed by Snapshot utilizing multiplexed PCR of common hotspot mutations using DNA derived from formalin-fixed, paraffin-embedded (FFPE) tissue.

Results: From a total of 213 patients with known ER status for multiple serial biopsies, we identified 9.4% (N=20) who had at least one change in ER status over time. From a total of 198 patients who had documented PR status for multiple biopsies, 40.4% (N=80) had at least one change in PR status. Changes in HER2 status were similarly assessed, with 6.7% of patients having at least one change by IHC and 4.4% of patients having at least one change by FISH. Of those patients exhibiting changes in ER status, 6 were noted to have multiple changes over time. Of those with changes in PR status, 18 had multiple changes over time. Changes in hormone receptor status were also noted to occur between serial biopsies in the metastatic setting. A total of 128 patients had ER results available for multiple metastatic specimens, of which 8.6% (N=11) had at least one change in ER status. A total of 116 patients had PR results available for multiple metastatic biopsies, of which 38.8% (N=45) had at least one change in PR status. Changes were also noted in the metastatic setting in HER2 (IHC) with a frequency of 8.7% and in HER2 (FISH) with a frequency of 4.7%. A subset of 108 patients were identified as harboring a mutation in PIK3CA. Within this population, 9.6% of patients had at least one change in ER status over time and 34.1% had at least one change in PR status. 9.0% exhibited at least one change in HER2 (IHC) and 6.5% in HER2 (FISH). Serial changes in genotype, from pre- and post-treatment biopsies, were also detected using NGS based Foundation Medicine platform, including acquired alterations in the ESR1 and PI3K pathway.

Conclusion: Serial changes in hormone receptor status and mutation profile are not uncommon among patients initially diagnosed with ER+/HER2 negative breast cancer, and some patients have been noted to have multiple changes over time. Further studies are needed to understand the mechanistic underpinnings governing the emergence of these alterations and their relationship to therapeutic resistance in breast cancer.

Citation Format: Henderson L, Brachtel E, Fitzgerald D, Gadd M, Specht M, Thabet A, Gurski J, Sgroi D, Moy B, Isakoff S, Bardia A, Juric D. Serial evolution of hormone receptor status and mutational profile among patients with metastatic breast cancer [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 P1-06-03.

Abstract P5-13-09: Development and implementation of a patient-centered, nurse practitioner-led survivorship intervention for breast cancer

This abstract was withdrawn by the authors.

Abstract P5-16-16: Role of tumor microenvironment, as assessed by breast MRI background parenchymal enhancement (BPE), in modulating response to neoadjuvant chemotherapy in young women with localized breast cancer

Background:

Neoadjuvant chemotherapy (NACT) is generally established as a therapeutic option for selected high-risk patients with localized breast cancer, including triple negative breast cancer (TNBC). On a patient level, achievement of pathologic complete response (pCR) at the time of surgery is associated with improved long-term outcomes and is considered to be a surrogate marker. Response to NACT is a complex phenomenon dependent on both host and tumor characteristics. While tumor characteristics, such as receptors and tumor grade, have been well studied as predictors of pCR, host characteristics to predict pCR have been less well studied. Background parenchymal enhancement (BPE) is an imaging characteristic that reflects the normal enhancement of the fibroglandular tissue on breast MRI, and could potentially modulate response to NACT by influencing the tumor microenvironment and vasculature. The aim of this study was to explore the ability of baseline BPE to predict pCR in a cohort of young women with localized breast cancer.

Methods:

A retrospective chart review was conducted of women ages 40 and under with stage II-III breast cancer treated with NACT at our institution from 2004 – 2014. Demographic, clinical, and pathological variables were extracted from the medical records. The primary outcome was achievement of pCR, defined as ypT0/is ypN0, after NACT. BPE pattern in the contralateral breast was obtained from pre-treatment breast MRI reports if available and otherwise was retrospectively determined by a breast radiologist blinded to patient outcomes. BPE was dichotomized as low (minimum and mild) vs. high (moderate and marked). Logistic regression was used for statistical analysis.

Results:

A total of 69 patients ages 40 and under received NACT for localized breast cancer during the study period and had available pre-treatment breast MRI images. Median age at diagnosis was 36 (range 27-40). The majority of patients had grade 3 (65.2%), ER+/HER2- (60.9%) tumors while 24.6% had TNBC. Among pre-treatment breast MRIs, 42 (60.9%) patients had minimum or mild BPE and 27 (39.1%) patients had moderate or marked BPE. The overall pCR rate was 39%. After controlling for tumor grade, ER status, HER2 status, clinical stage, and type of NACT, high baseline BPE was associated with a trend towards higher odds of achieving pCR compared to low BPE (OR = 1.49, 95% CI 0.47–4.71), though statistical significance was not reached (p = 0.50). When stratified by ER status, the relationship was stronger among the ER+ subset (OR 1.8, p = 0.49) compared to the ER- subset (OR 1.3, p = 0.78).

Conclusions:

A statistically significant association between high baseline BPE and achievement of pCR was not found in this limited sample size, but a trend towards higher pCR rates, particularly with ER+ tumors, was seen. While tumor factors have traditionally been used to predict pCR, BPE is a readily available MRI imaging characteristic that reflects the tumor microenvironment and may be useful in building a model that incorporates tumor factors along with host factors to develop personalized NACT regimens for young women with breast cancer.

Citation Format: Spring L, Rutledge G, Yala A, Haddad S, Specht M, Moy B, Barzilay R, Lehman C, Bardia A. Role of tumor microenvironment, as assessed by breast MRI background parenchymal enhancement (BPE), in modulating response to neoadjuvant chemotherapy in young women with localized breast cancer [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 P5-16-16.

Abstract P1-12-03: Association between tumor genotype and development of brain metastases in patients with hormone receptor positive (HR+)/HER2- metastatic breast cancer

Introduction: Historically, brain metastases are considered to be uncommon in HR+/HER2- breast cancer compared to triple-negative or HER2+ breast cancer. However, improved systemic therapy and prolonged overall survival in patients with metastatic HR+/HER2- breast cancer may result in increased incidence of brain metastases as most currently available therapeutic agents do not penetrate blood-brain barrier giving the brain a sanctuary site status. Although certain tumor cells may also exhibit brain-specific tropism or may have selective growth advantage in the brain microenvironment, biological factors that govern metastases to brain, including role of PIK3CA mutations, are poorly understood. In this study, we review our clinical experience with the brain metastases among patients with metastatic ER+/HER2- breast cancer, including their association with PIK3CA genotype.

Methods: Since 2008, at our institution, a multiplexed tumor genotyping assay (SNaPshot), has been utilized to assess for presence of potentially actionable oncogenic driver mutations, including PIK3CA, using DNA derived from formalin-fixed, paraffin-embedded (FFPE) tissue. We identified patients with metastatic HR+/HER2- breast cancer who had tumor genotyping performed at any point during their care and who had at least 6 months of follow-up in our clinic. Relevant clinical information, including development of brain metastases, was gathered from chart reviews.

Results: From a total of 251 patients with HR+/HER2- metastatic breast cancer, 23.5% (N=59) developed brain metastases. Approximately 1/3rd of patients (31.7%, N = 20) had brain metastases seen on imaging as an incidental finding, while others presented with 1-2 symptoms that could be associated with CNS disease, including ataxia/weakness (34.9%), visual/speech difficulties (26.9%), headaches (23.8%), altered mental status (14.3%), seizures (14.3%), and nausea (9.5%). PIK3CA mutations were identified in 45.2% of all patients, including mutations in both helical (exon 9) and kinase (exon 20) domains. Patients with tumors harboring PIK3CA mutations had significantly higher incidence of brain metastases, as compared to those without PIK3CA mutations (30.7%, versus 18.7%; p = 0.034). The median time between diagnosis of metastatic disease and diagnosis of brain metastasis was longer among those patients with PIK3CA mutation (32 months) as compared to those without PIK3CA mutation (18 months).

Conclusion: Brain metastases are common among patients with HR+/HER2- breast cancer, particularly HR+/HER2- breast cancer harboring PIK3CA mutations where it approaches the incidence historically seen in HER2+ breast cancer. Early recognition and appropriate diagnostic work-up of any symptoms potentially associated with presence of CNS disease is necessary in PIK3CA-mutant HR+/HER2- breast cancer. Further studies are needed to explain the mechanistic link between the PIK3CA mutant phenotype, phosphatidylinositol 3-kinase (PI3K) pathway activation and CNS disease.

Citation Format: Fitzgerald DM, Henderson LE, Isakoff SJ, Moy B, Oh K, Shih HA, Dias-Santagata D, Borger DR, Iafrate AJ, Brastianos PK, Bardia A, Juric D. Association between tumor genotype and development of brain metastases in patients with hormone receptor positive (HR+)/HER2- metastatic breast cancer [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 P1-12-03.

Abstract P1-05-05: Comparison of genotyping results from tissue and circulating DNA (ctDNA) in patients with metastatic breast cancer

Introduction: Robust clinical genotyping assays are crucial to accelerate development of targeted therapies toward tumor-specific oncogene pathways. Indeed, there has been an explosion in the development of genotyping assays and stratified enrollment in clinical trials based on molecular characteristics of the tumor. However, availability of tissue can be a significant barrier for genotyping, particularly patients with estrogen receptor positive (ER+) breast cancer, who frequently have bone only metastasis. Detection of mutations in circulating tumor DNA (ctDNA) represents an attractive alternate strategy. However, there is a paucity of data comparing genotyping results from tissue and ctDNA, and potential clinical utility for patients with metastatic breast cancer.

Methods: Analysis of ctDNA was based on Guardant 360 panel (2015), a next-generation sequencing (NGS) based assay that covers point mutations in 70 genes (complete or critical exon coverage) with select amplifications, fusions, and indels, using NGS Illumina HiSeq platform, validated to detect alterations in samples with at least 2% ctDNA. Molecular profiling of tissue was based on the institutional lab-developed test “Snapshot-NGS assay”, utilizing a multiplex polymerase chain reaction (PCR) technology called Anchored Multiplex PCR (AMP) for single nucleotide variant (SNV) and insertion/deletion (indel) detection in genomic DNA targeting hotspots and exons in 39 genes using NGS Illumina MiSeq platform, validated to detect SNV and indel variants at 5% allelic frequency or higher in target regions.

Results: In the analytical dataset, a total of 42 patients with metastatic breast cancer (median age 62) at our institution had ctDNA and tissue Snapshot-NGS results available. Out of these, 95% had at least one genetic alteration detected in ctDNA, before start of a new therapy. The common genetic alterations in ER+ disease (n = 33) included PIK3CA (39.4%), ESR1 (27.3%), and AKT1 (15.2%); HER2+ disease (n = 2) included PIK3CA and CCND1; TNBC (n = 7) included TP53 (71.4%). Gene amplifications in FGFR, PIK3CA, CCND1, MYC, and KRAS were also noted. In general, the average number of molecular alterations was higher in ctDNA than the tissue specimen (mean = 5.1 vs 1.1; p < .001). Of 34 patients with actionable alterations detected in ctDNA, 76.5% of these patients did not have actionable alterations detected in tissue. Of 29 patients with actionable alterations detected in tissue (primary or metastatic), 13.8% of these patients did not have any actionable alterations detected in ctDNA.

Conclusion: A significantly higher number of genomic alterations were detected in ctDNA compared to tissue, including actionable alterations linked to potential targeted therapies. Given these findings and the difficulties with tissue-based genotyping assays, blood based biomarker assays might provide an alternative and effective way to obtain a comprehensive molecular profile, and potentially guide management decisions for patients with metastatic breast cancer.

Citation Format: Malvarosa G, Spring L, Juric D, Moy B, Bardia A. Comparison of genotyping results from tissue and circulating DNA (ctDNA) in patients with metastatic breast cancer [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 P1-05-05.

Abstract P4-03-04: Dynamic tomographic optical breast imaging (TOBI) for neoadjuvant chemotherapy monitoring

Background: Dynamic Diffuse optical imaging using near-infrared light was shown to be promising method for neoadjuvant therapy monitoring as an alternative functional imaging that is low-cost, non-invasive, portable, safe and simple to operate. While optical breast imaging methods rely on "static" assessments of tissue oxy- and deoxy- hemoglobin concentration without contrast agents, they are insufficient for clinical applications. Dynamic tomographic optical imaging induces tumor-sensitive hemodynamic variations, as a contrast mechanism, driven by fractional mammographic compression. These tumor contrast measurements are governed by interlay of tissue biomechanics and oxygen metabolism. In this study we seek to evaluate the predictive value of these biomarkers with respect to treatment outcome.

Methods: A group of 22 patients with locally advanced breast cancer were scanned using our dynamic TOBI system before and during neoadjuvant chemotherapy. In this analysis we focused on pre-treatment, day 7 and day 30 post-treatment dynamic TOBI scans. Both breasts are compressed in turn to 4-8 lbs of force (depending on size) and optical images are acquired every 2 seconds over 2 minutes. We calculate the time course of oxy (HbO), deoxy (HbR)and total (HbT) hemoglobin concentration as well as the hemoglobin oxygen saturation (SO2). Regions of interest are defined in the optical images to correspond to the radiology identified tumor location, and the healthy tissue in the same breast, respectively. We compare the time courses in the two regions at baseline, day 7 and 30 days after initiation of treatment.

Results: In this analysis we present results from 10 patients including 6 responders (defined as greater than 50% reduction in the largest tumor axis from baseline imaging and final pathology) and 4 non-responders. As the compression plates are held in place the tissue collagen matrix begins to stretch, effectively reducing the compression force. At baseline, all patients exhibit a decrease followed by delayed recovery in HbT, and SO2 in the tumor area, in contrast to immediate recovery in surrounding tissue. At day 7 and 30, this contrast is maintained in non-responders (<50% reduction in tumor maximum diameter); however, in responders, the contrast starts decreasing at day 7 and substantially disappears at day 30. Average changes in HbT and SO2, show that the contrast between normal and tumor increases somewhat at day 7 and more noticeably at day 30 in non-responders to NACT. Comparing hemodynamic changes in responders and non-responders, it is clear that at three selected time points (30, 60 and 90 s) during the scan, the contrast between tumor and normal tissue in both ΔHbT and ΔSO2 is reduced for the responders at day 7 and day 30.

Conclusions: These initial results suggest that dynamic optical breast imaging can detect changes due to treatment and have predictive value for the treatment outcome. DTOBI can show the difference in hemodynamic response to compression between tumor and normal tissue and demonstrates the feasibility of using dynamic optical breast tomography for neoadjuvant chemotherapy monitoring. ongoing.

Citation Format: Sajjadi AY, Singh B, Deng B, Boas DA, Moy B, Schapira L, Bardia A, Specht MC, Carp SA, Isakoff SJ. Dynamic tomographic optical breast imaging (TOBI) for neoadjuvant chemotherapy monitoring. [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 P4-03-04.

Abstract P4-02-01: Normalization of compression-induced hemodynamics in patients responding to neoadjuvant chemotherapy using dynamic tomographic optical breast imaging (TOBI)

Background: Diffuse optical imaging using near-infrared light is emerging as a promising non-invasive method for breast neoadjuvant chemotherapy (NAC) monitoring and outcome prediction. While the majority of published studies rely on “static” assessments of tissue oxy- and deoxy- hemoglobin concentration, we have focused on extending diffuse optical tomography to capture hemodynamic changes driven by fractional mammographic compression. These hemodynamic changes are governed by the interplay of tissue biomechanics and oxygen metabolism, and thus form a novel class of optical dynamic biomarkers of breast pathology. In this study we seek to evaluate the predictive value of these biomarkers with respect to treatment outcome.

Methods: We are conducting a pilot feasibility study in female patients with unilateral locally advanced breast cancer undergoing standard of care NAC. In this analysis we focused on pre-treatment and day 30 post-treatment dynamic TOBI scans. Both breasts are compressed in turn to 4-8 lbs of force (depending on size) and optical images are acquired every 2 seconds over 2 minutes. We compute the time course of oxy (HbO), deoxy (HbR)and total (HbT) hemoglobin concentration as well as the hemoglobin oxygen saturation (SO2). Regions of interest are defined in the optical images to correspond to the radiology identified tumor location, and the healthy tissue in the same breast, respectively. We compare the time courses in the two regions at baseline, and 30 days after initiation of treatment.

Results: In this analysis we present results from 6 patients including 3 responders (defined as greater than 50% reduction in the largest tumor axis from baseline imaging and final pathology) and 3 non-responders. As the compression plates are held in place the tissue collagen matrix begins to stretch, effectively reducing the compression force. At baseline, all patients exhibited an initial decrease in HbT, HbO and SO2. In the tumor area, this was followed by little or no recovery as the compression plates were held in place. The normal tissue, in contrast, began recovering almost immediately. At day 30, the tumor area in the non-responders displayed similar time-course characteristics to day 0. Interestingly, however, at day 30 responders had a very similar time course in both the tumor and normal area, characterized by a slow recovery that begins soon after the compression plates stop moving. Table 1 summarizes the changes in total hemoglobin at t = 90 seconds.

Conclusions: At day 30 after NAC, responding tumors demonstrated “normalization” of compression induced hemodynamics in the tumor area whereas nonresponding tumors did not. This encouraging data suggests that dynamic TOBI can easily detect changes due to treatment. Complete analysis of the patient data to assess the outcome prediction ability using this novel optical imaging technology is ongoing.

Compression induced changes in total hemoglobin a t = 90 seconds during compressionΔHbTtumor- ΔHbTnormal (μM)RespondersNon-RespondersDay 0-0.65 ± 0.21-0.82 ± 0.24Day 300.10 ± 0.24-1.13 ± 0.74

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-02-01.

Abstract P2-16-04: A phase 2 study of ridaforolimus (RIDA) and dalotuzumab (DALO) in estrogen receptor positive (ER+) breast cancer

Background: Preclinical studies indicate that the dual inhibition of IGFR and mTOR may be additive or synergistic and abrogates the feedback activation of AKT due to rapamycin analog mTOR inhibitors. A phase 1 study of the mTOR inhibitor RIDA and the anti-IGFR antibody DALO demonstrated that the combination was feasible and well-tolerated at doses that were nearly those used for the two single agents. The dose limiting toxicity was stomatitis, similar to RIDA monotherapy. Preliminary signals of anti-tumor activity, including partial responses and prolonged progression free survival (PFS), were observed in ER+ advanced breast cancer (ABC), especially in high proliferation tumors (Ki67 ≥15%). Methods: The trial was a multi-center, international randomized study with PFS as the primary endpoint. Key eligibility included ABC with prior treatment with a non-steroidal aromatase inhibitor. The original phase 2 study design was a two-part, adaptive design intended to first test the combination of RIDA (30 mg by mouth daily for 5 out of every 7 days), -DALO (10 mg/kg IV weekly) against a standard agent, exemestane in Part A. Patients were stratified into high and low proliferation strata based on baseline Ki67. Following a demonstration of PFS benefit of the combination in Part A, Part B was intended to show the PFS benefit of the combination over each single agents by comparing RIDA-DALO to RIDA and DALO. Results: The study was initiated in October 2011. Accrual was suspended after the first 66 patients were randomized due to a higher than expected rate of stomatitis in the RIDA-DALO arm. Preliminary data indicated an overall incidence of any grade stomatitis was 68% (22/33 pts), and of grade 3 stomatitis was 35% (11/33 pts). In an effort to identify a more tolerable regimen, the study was amended to eliminate Part B and to evaluate two sequential reduced dose RIDA-DALO cohorts in a non-randomized design: 20mg and 10mg for 5 out of every 7 days. The dose of DALO was unchanged. Preliminary safety results of overall and grade 3 stomatitis in the 20 mg were 81.5% (22/27 pts) and 37% (10/27 pts), respectively. Although the incidence of overall stomatitis in the 10 mg cohort remained high, 88% (22/25 pts), grade 3 stomatitis was dramatically reduced to 8% (2/25 pts). Conclusion: Preliminary evaluation of safety from this phase 2 study demonstrates that the previously recommended phase 2 dose of RIDA-DALO was not tolerable. However lower doses of RIDA (10 mg) in combination with DALO appeared to be tolerable with markedly reduced rates of grade 3 stomatitis. Final results of efficacy, safety and RNA profiling analysis from the two RIDA-DALO dose cohorts as well as from the randomized portion of the study will be available at the time of the meeting.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-04.

Abstract P4-12-02: High HER2 gene amplification and clinical outcomes in localized HER2-positive breast cancer

BACKGROUND

Anti-HER2 therapy with trastuzumab is associated with a significant improvement in disease-free survival as compared to chemotherapy alone, and is considered the standard of care for localized HER2 positive breast cancer. However, a subset of HER2 positive breast cancers do not respond to trastuzumab. While various mechanisms have been proposed for trastuzumab resistance, one potential contributor could be very high level of HER2 gene amplification. Since trastuzumab is a HER2 receptor antagonist, it is possible that single agent trastuzumab might be unable to block HER2 downstream signaling thresholds efficiently in the presence of very high HER2. The clinical outcomes for tumors with high HER2 gene amplification treated with trastuzumab have not been well studied.

METHODS

With IRB approval, we reviewed the clinical records of all Stage I-III breast cancer patients with HER2+ breast cancer at our institution from 2008-2012. HER-2 to Chromosome 17 FISH ratio was determined by two pathologists with high inter-person reliability using the PathVysion dual color probe (Abbott Laboratories). We abstracted data on demographics, tumor characteristics including tumor size (T), lymph node involvement, grade, DCIS, HER2 amplification levels, and clinical outcomes from the clinical charts. We defined high HER2 amplification as FISH ratio > 8.0, as used in the HERA trial. Categorical data are summarized by frequency and percentage and comparisons between groups are performed by chi-square tests. In addition, we conducted a meta-analyses and systematic review to evaluate the association between high HER2 gene amplification and clinical outcome with/without trastuzumab in the large adjuvant HER2 clinical trials.

RESULTS

A total of 503 patients with HER2+ breast cancer were seen between the years of 2008-2012, and 16% (N = 82) had tumors with high HER2 levels. The median age was 50.5 years (range 29-89). The majority of tumors were T1 (56.79%) or T2 (34.57%), and had HER2 IHC staining of 3+ (94.37%). Tumors with high HER2 levels were more likely to be ER-/PR- (48.4%) than ER+/PR+ (32.8%) or ER+/PR- (18.8%), and likely to have concomitant DCIS (82.5%) and high grade (grade 3 = 74%). Women (n = 16) with high HER2+ breast cancer treated with standard neoadjuvant therapy with single agent trastuzumab (AC-TH or TCH) had a low pathological complete response (pCR) rate of 7.14%. In addition, this group had a high recurrence risk of 42.9%. Two patients with recurrence had mutation profiling by multiplexed genotyping platform (SNaPshot) and mutations in PIK3CA and TP53 oncogene were identified.One patient with grade 3, high HER2+ (FISH 8.2) microinvasive DCIS, treated with mastectomy, developed pulmonary metastases 3 years after original diagnosis. The meta-analysis revealed adjuvant trastuzumab with chemotherapy did not result in improved disease free survival as compared to chemotherapy alone among tumors with high FISH ratio (Hazard Ratio: 0.89, 95% CI: 0.57, 1.38; p = 0.60).

CONCLUSIONS:

Our results suggest that tumors with high HER2 amplification, including small tumors, have an aggressive biology, are less likely to respond to standard trastuzumab based therapy, and more likely to have a recurrence, compared with historical HER2 controls. High FISH may predict a clone of cells that have resistance to single agent trastuzumab warranting more aggressive HER2 directed therapy such as dual HER2 or combined HER2 and PI3K/Akt/mTOR blockade. These findings need confirmation in additional studies.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-12-02.

Abstract P1-01-13: Patterns of definitive axillary management in the era prior to reporting ACOSOG Z0011: comparison between NCCN Centers and hospitals in Michigan

Background: The results of the ACOSOG- Z0011 trial have had potential practice changing implications for the management of patients with positive sentinel lymph node (SLN) undergoing lumpectomy and radiation for breast cancer. However, some evidence suggests a shift in axillary management even prior to the initial report of data supporting sentinel lymph node biopsy (SLNB) alone in mid-2010. We analyzed data in the National Comprehensive Cancer Network (NCCN) outcomes database from NCCN centers and the Michigan Breast Oncology Quality Initiative (MiBOQI) hospitals to examine institutional practice patterns with respect to use of completion axillary dissection (CALND) for SLN positive breast cancer in the years leading up to publication of these trial results. We hypothesized that CALND would be omitted more frequently in women treated at NCCN centers compared to those treated at MiBOQI programs.

Methods: We identified 2,172 women with clinical T1/T2 N0 breast cancer who underwent breast surgery and SLNB and had a positive SLN from 2007 through 2010 at one of 12 participating NCCN centers or 12 MiBOQI sites. Patient and tumor characteristics, definitive breast procedure, year of diagnosis, and institutional affiliation were analyzed as predictors of use of SLNB alone in univariate Chi-Square and multivariable logistic regression models.

Results: CALND was omitted in 314 (14.5%) of the 2,172 patients. Over time, there was a dramatic increase in the use of SLNB alone (12% in 2007 to 23% in 2010). In the univariate analyses, increased patient age, later year of diagnosis, lower T stage, and lower pathologic N stage were significant predictors of use of SLNB alone (all p < .0001). There was no association between definitive breast surgery type, hormone receptor status, Her-2 Neu status, or institutional affiliation and use of SLNB alone. In the multivariable model, older age at diagnosis, later year of diagnosis, and lower pathologic N stage remained significant independent predictors of SLNB alone. There were no significant differences in rates of omission of CALND between NCCN and MIBOQI sites.

Abstract P3-06-27: Dynamic tomographic optical breast imaging (TOBI) to monitor response to neoadjuvant therapy in breast cancer

Background: Near-infrared optical measurements have been recently shown to offer a promising non-invasive way for monitoring breast neoadjuvant chemotherapy (NAC) and predicting outcome. In particular, snapshots of tissue oxy and deoxy-hemoglobin concentration as well as water and lipid content have been demonstrated to be sensitive to therapy-induced changes. In this study, we extend optical measurements to capture additional hemodynamic and metabolic biomarkers revealed by dynamically imaging breast tissue during fractional mammographic compression. Using our dynamic tomographic optical breast imaging (TOBI) system we evaluate the early prediction performance of this advanced technology.

Methods: We are conducting a pilot feasibility study in female patients with unilateral locally advanced breast cancer undergoing standard-of-care NAC. Pre-treatment and day 7 post-treatment TOBI scans are obtained, with additional (optional) scans on day 1 of each subsequent chemotherapy cycle. Both breasts are compressed in turn to 4–8 lbs of force, and optical images are acquired once every 2 seconds over two minutes. Time-resolved oxy-(HbO), deoxy-(HbR), and total-(HbT) hemoglobin concentration and hemoglobin oxygen saturation (SO2) are calculated. The compression-induced rate of change of HbT correlates with changes in tissue blood volume indicative of biomechanical properties. The evolution of tissue SO2 is modeled to obtain an index of the ratio of oxygen metabolism to blood flow. Therapy induced changes are quantified, and comparisons between changes in responders vs. non-responders are performed (response is defined here as >50% reduction in the largest tumor diameter).

Results: We have enrolled 20 patients so far, of which 90% (N = 18) completed both the day 0 and day 7 scans. 17 patients have undergone surgery at this point. We focused our initial analysis on 5 HER2+ patients, of which two were non-responders, and three were responders according to our criteria. Four patients received taxol+herceptin+lapatinib, while the other received taxol+lapatinib only. In this small subgroup, the non-responders had an average increase of 1% in total hemoglobin concentration (HbT) from day 0 to day 7, while the responders had an average 12% decrease in HbT, respectively. We also noted different trends in the evolution of the tissue oxygen consumption to blood flow ratio, which increased 32% in non-responders from day 0 to day 7, while decreasing 11% in responders.

Conclusions: The large percentage of enrolled patients that completed both initial scans demonstrates the feasibility of using dynamic optical breast tomography for breast neoadjuvant chemotherapy monitoring. Results in a small cohort of 5 HER2+ patients suggested a decreasing trend in HbT for responders as observed by previous studies. We also report for the first time an increase in the metabolic ratio of oxygen consumption to blood flow in non-responders vs. a decrease in responders. These initial results of our on-going study suggest that dynamic TOBI can detect changes due to treatment and may have predictive value for the treatment outcome and supports further studies of this non-invasive and portable tool for chemotherapy monitoring.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-06-27.

P1-11-10: Quality of Breast Cancer Care in a Boston Area Patient Navigator Program

Background: Elimination of disparities is critically important for lessening the burden of cancer. Patient navigator programs (PNPs) assist with all aspects of care, including access, cancer prevention, screening, post-diagnosis care, and survivorship care. Little is known about the effect of PNPs on patient care and outcomes following the diagnosis of breast cancer (BC). We examined quality measures (QMs) of breast cancer care among women participating in the Massachusetts General Hospital Avon Breast Care Patient Navigator Program (MABCP), which provides patient navigation services to disadvantaged minority communities in the greater Boston area.

Methods: Women diagnosed with BC who participated in the MABCP from 2001 to 2011 were followed to determine the proportion whose care was concordant with American Society of Clinical Oncology/National Comprehensive Cancer Network (ASCO/NCCN) QMs. QMs included 1) hormonal therapy (HT) within 1 year of diagnosis for HR+ tumors > 1 cm; 2)chemotherapy within 120 days of diagnosis of HR- >1cm tumors for women <70 years; and 3) post-lumpectomy radiation therapy (XRT). Descriptive statistics were used to report characteristics of MABCP patients.

Results: Of the 186 MABCP patients diagnosed with BC, some treatment data was available on 158 (85%) and race/stage information was available on 149 (80%) [Table 1]. Among the MABCP patients, concordant care was received by 70/74 (95%) for the HT QM, 15/17 (88%) for the chemotherapy QM, and 65/71 (92%) for the XRT QM. In comparison, available benchmark concordance rates of BC patients treated at 8 NCCN centers from 2003–6 are: 340/382 (89%) for the HT QM, 156/179 (87%) for the chemotherapy QM, and 141/148 (95%) for the XRT QM.

Conclusions: Overall, breast cancer care in the MABCP PNP is concordant with published ASCO/NCCN quality measures. At present, the sample is insufficient to compare concordance rates with NCCN patients but preliminarily, it appears that the quality of care is comparable. Future research should include prospective analyses of quality metrics to assess the process and outcomes of patient navigation in diverse settings, compared with control populations.

P1-12-26: Global Patterns of Care for HER2/Neu Overexpressing Breast Cancer

Background: Her2/neu overexpression is an independent adverse prognostic factor present in approximately 25% of invasive breast cancers. HER2−overexpressing breast cancer is particularly common in younger patients and therefore poses a significant public health burden. Anti-Her2/neu adjuvant trastuzumab significantly reduces the risk of recurrence as well as improves survival. In view of the serious potential ramifications of not receiving anti-Her2/neu therapy when appropriate, we undertook this international project to determine clinical access to Her2/neu testing and treatment patterns for women with HER2/neu-positive early breast cancer.

Methods: A web-based survey was sent to 386 physicians from 33 countries who participated in the “TEACH” trial, a double blind placebo-controlled phase III study of a novel anti-Her2/neu therapy, lapatinib, in women with primary Her2/neu-positive breast cancer. The survey contained 27 questions addressing physician and patient demographics, access to Her-2/Neu testing in everyday clinical practice, and anti-Her2/neu treatment options in a variety of clinical scenarios.

Results: One hundred and fifty one participants (39%) from 28 countries answered the survey. Ninety eight percent of the participants reported having Her2/neu tumor expression routinely measured for clinical practice in their institutions by immunohistochemistry (83%), FISH (78%) and other methods (17%). Among Asian physicians, 18% did not have routine testing available and sent primary tumors for central testing for TEACH eligibility. Forty eight percent of physicians surveyed reported instances when they had recommended adjuvant Her2-directed therapy to a patient who eventually did not receive it. The proportion of physicians from developing countries that reported patients not receiving therapy was higher than those from developed countries (68% vs. 38%, respectively). The main reason for not receiving trastuzumab was cost in developing countries, while in more developed countries patient refusal and co-morbidities were the main reasons.

Discussion: This survey reflects availability of HER2 breast tumor testing and anti-Her2/neu therapy among physicians from 28 countries worldwide who participated in an anti-Her2/neu therapy clinical trial of a free anti-Her2/neu therapy. These results indicate that a high proportion of women with Her2/neu-overexpressing breast cancer may not receive standard anti-Her2/neu adjuvant therapy especially in developing countries, the barrier to treatment being cost of therapy. We are extending our access to care survey project to a more unselected diverse group of physicians in developing countries.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-12-26.

Functional metabolic tomographic optical breast imaging (TOBI) to monitor response to neoadjuvant therapy in breast cancer

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Background: Recent studies using near-infrared optical measurements in breast tumors have demonstrated the promise of early monitoring of neoadjuvant chemotherapy (NAC) to predict outcome. Technologies to date have focused primarily on static measurements. Dynamic optical imaging, in conjunction with fractional mammographic compression, offers access to multiple functional and metabolic tissue biomarkers that may be used to predict treatment response. We have developed a novel tomographic optical breast imaging (TOBI) device to evaluate the early (day 7) prediction performance of this advanced technology.

Methods: We are conducting a pilot feasibility study in female patients with unilateral locally advanced breast cancer undergoing standard-of-care NAC. Pre-treatment and day 7 post-treatment TOBI scans are obtained, with additional scans on day 1 of each subsequent chemotherapy cycle. The affected and contralateral normal breasts are compressed to 6-8 lbs of force and optical images are acquired once every 2 seconds for two minutes. Time-resolved oxy-(HbO), deoxy-(HbR), and total-(HbT) hemoglobin concentration and hemoglobin oxygen saturation (SO2) are calculated. The compression-induced rate of change of HbT correlates with changes in tissue blood volume indicative of biomechanical properties and the evolution of tissue SO2 estimates tissue metabolism.

Results: We report initial data from two patients. One patient had a near-pathologic complete response (responder) and showed 21% and 23% decreases in HbT and HbR, respectively. The second patient had no significant response (non-responder) and had 2% and 1% decreases in HbT and HbR, respectively. Interestingly, the responder showed a dynamic decrease in HbT during compression in the tumor region at day 0 that disappeared at day 7, while the non-responder had similar rates of HbT change at both scans.

Conclusions: We demonstrate for the first time the feasibility of dynamic optical breast tomography and show that optically derived parameters may be sensitive to therapyinduced changes in breast cancer. These dynamic measurements may provide novel insight into the physiologic changes in breast tumors during treatment.

The Quality of Decisions about Adjuvant Chemotherapy for Early Stage Breast Cancer

Background: Decisions about adjuvant chemotherapy are highly challenging for many women with early stage breast cancer. We sought to assess the quality of breast cancer patients' decisions about chemotherapy by measuring their knowledge and the degree to which their treatment decisions reflect their goals and preferences.Methods: We mailed a survey to early stage (I, II) breast cancer survivors who were treated at one of four sites, as part of a larger study to validate decision quality instruments. A subset of women completed the chemotherapy module, which included questions about the patient-provider interaction, about facts, about treatment goals, and about the patient's preferred treatment. Characteristics associated with knowledge were identified with linear regression. Characteristics associated with chemotherapy were identified with logistic regression.The percentage of patients who received their preferred treatment was calculated.Results: 358 patients completed the survey (response rate 59%). 64% of patients had Stage I disease, and 57% had chemotherapy. Average age was 56.9 years, 82.6% were white, and 63.7% had a college degree.Decision making: 70% of patients reported that their provider mentioned chemotherapy as an option. 43% reported that their provider asked for their preference about chemotherapy. 23% said the doctor mainly made the decision, 29% said they mainly made the decision, and 46% said both made the decision.Most women (92%) felt their level of involvement was about right.Knowledge: The mean knowledge score was 39.6% (SD 20.3). 29.9% knew that less than half of women with early stage breast cancer eventually die from breast cancer without chemotherapy or hormone therapy.21.8% knew that more than half are free from recurrence in 10 years without chemotherapy or hormone therapy. Chemotherapy treatment and the doctor having discussed chemotherapy were significantly associated (p<0.05) with higher knowledge. Younger age at diagnosis, white race, higher income, and a college degree were also significantly associated with higher knowledge (p<0.05).Treatment: Factors associated with having chemotherapy were younger age (OR 1.71, 95% CI 1.01, 2.91) and not having hormone therapy (OR 3.2, 95% CI 1.92, 5.42). Factors associated with not having chemotherapy were lower stage (OR 0.17, 95% CI 0.10, 0.30), mastectomy (OR 0.47, 95% CI 0.26, 0.86), and the goal “live as long as possible” (OR 1.41, 95% CI 1.10, 1.80).Concordance with preferences: 81.6% of patients who preferred chemotherapy received it, and 92.6% of patients who preferred no chemotherapy received no chemotherapy.Conclusion: Breast cancer patients had substantial knowledge deficits about chemotherapy, which were even more prevalent among older, non-white, less educated, and lower-income women. In addition, more than half of women reported they were not asked about their preferences, and some reported getting chemotherapy treatment that was not concordant with their preferences.Oncologists should address knowledge deficits and explicitly ask patients their preferences.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2083.

Dose-Dense (dd) Doxorubicin and Cyclophosphamide (AC) Followed by Weekly Paclitaxel (P) with Trastuzumab (T) and Lapatinib (L) in Early Breast Cancer (EBC); Troponin I and C-Reactive Protein as Biomarkers of Cardiotoxicity

BackgroundThe early detection of cardiotoxicity and congestive heart failure (CHF) from anthracyclines and anti-HER2 agents is currently limited to measuring changes in left ventricular ejection fraction (LVEF) at arbitrary time points. This approach has limited sensitivity and specificity and has led to the investigation of putative biomarkers such as cardiac Troponin I (TnI), a highly specific marker of myocardial damage and C-reactive protein (CRP), a sensitive inflammatory marker. In a pre-planned analysis we investigated these as biomarkers of cardiotoxicity within a prospective study testing the feasibility of ddAC- followed by weekly P with T and L.Materials and MethodsPatients (pts) with HER2+ EBC enrolled at MSKCC and DF/HCC and received ddAC (A 60mg/m2 + C 600mg/m2) x 4 → weekly P (80mg/m2) x 12 + T + L (1000mg/day). T+L continued for a total of 1yr. At baseline pts had LVEF ≥50%. Pts with unstable angina, CHF, recent MI, uncontrolled arrhythmia, grade 3 QT prolongation were excluded. LVEF was assessed by MUGA scan at mths 0, 2, 6, 9 and 18. TnI and CRP were measured every 2 wks right before treatment (Rx) during ddAC-PTL, then at mths 6, 9 and 18. TnI was categorized as “undetectable” (< 0.06 ng/ml; MSKCC, <0.04 ng/ml; DF/HCC), “minimally elevated” (<0.31 ng/ml) and “elevated” (>0.31ng/ml). Elevated CRP was defined as (>0.8mg/dl; MSKCC, >0.3mg/dl; DF/HCC). Investigators were blinded to these results until pts completed 18mth follow-up (F/U).ResultsFrom Apr 07- Apr 08, 95 pts were enrolled; 39/95 (41%) withdrew due to PTL toxicities (incl. 3 with asymptomatic LVEF (aLVEF) declines and 3 with CHF). Final biomarker results were available in 84 pts (88%) and 11 pts (12%) continue on study. During Rx, minimal elevations in TnI occurred in 55 pts (65%). One pt had ↑TnI above normal range with AC#4; MUGA 1 wk later was unchanged (LVEF 75%), but she died from sepsis during subsequent Rx without evidence of CHF. Elevations in TnI occurred only during chemoRx and no pt had a ↑TnI during TL or at 18mth F/U. Of 55pts with elevated TnI, 25 (45%) had aLVEF declines (3 ↓ ≥16%, 10 ↓ 10-15%, 12 ↓ 5<10%). Of 29 pts with undetectable TnI, 7 (24%) had aLVEF declines (1 ↓ ≥16%, 4 ↓ 10-15%, 2↓ 5<10%). Elevations in CRP occurred in 61/84 (73%) pts during chemoRx but only in 22 (26%) during TL or at 18mth F/U. Three pts discontinued Rx for aLVEF ↓ at mths 4, 5 and 7 respectively; 2 (66%) had rises in CRP and 2 had minimal elevation in TnI. Three pts developed CHF at mths 3, 6, and 12 respectively, all had rises in CRP; 1 pt had a single ↑TnI of 0.08 ng/ml during chemoRx, and 2pts had no ↑TnIs.ConclusionsIn pts receiving ddAC-PTL fluctuations in TnI and CRP are common but do not persist after chemoRx (during TL). These biomarkers do not appear to predict for CHF. One possibility is that the timing of the drawing of these biomarkers (immediately preceding the specified treatment cycle and after Rx completion) may have been suboptimal. We plan to assess for potential biomarkers by assessing both immediately preceding and following therapy in a planned trial. Updated results will be presented.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3088.

Decisions about Breast Reconstruction after Mastectomy: Patient Involvement, Knowledge, and Preferences

Background:Most breast cancer patients who have a mastectomy do not have breast reconstruction, and rates of reconstruction vary by race, education, and geographic location, suggesting problems with decision making. We sought to assess the quality of decisions about breast reconstruction by measuring patient involvement in decision making, patient knowledge, and the degree to which decisions reflected patients' goals.Methods: Breast cancer survivors from four sites who were treated with mastectomy in the past 3 years completed a mailed survey, as part of a larger study to validate decision quality instruments. The survey contained questions about the decision making process, factual questions, and questions about personal goals and concerns. Characteristics associated with knowledge were identified with linear regression. Goals/concerns associated with reconstruction were identified using logistic regression. The percent match between treatment preference and treatment received was calculated.Results: The larger study recruited 456 patients (overall response rate 59%). 91 patients completed the reconstruction module. Average age was 56.9 years, 82.6% were white, 63.7% had a college degree, and 64% had Stage I disease. 45.8% had reconstruction.Decision making: 78% of patients reported that their doctor mentioned reconstruction. Most reported a discussion of the pros of reconstruction (63.8%), whereas the minority reported a discussion of the cons (20.9%). 76% reported being asked for their preference about reconstruction. 3% said the doctor mainly made the decision, 74% said they made the decision, and 15% said both made the decision. Most (81%) felt their level of involvement was about right.Knowledge:The mean knowledge score was 32.9% (SD=19). 41% knew that reconstruction has little effect on cancer surveillance. 54% knew that recovery after implant surgery is easier than after flap surgery. 3.3% knew that about 1/3 of patients have a major complication. On bivariate analysis, reconstruction (43.3 vs. 32.6, p=0.053), higher income (43.4 vs. 26.3, p=0.008), a college degree (43.4 vs. 26.2, p<0.01), and being married (40.9 vs. 29, p=0.04) were associated with higher knowledge. On multivariate analysis, higher income was associated with higher knowledge (p=0.0013).Preferences:The following goals were associated with reconstruction: “use your own tissue to make a breast” (OR 1.309, CI 1.028, 1.605), “avoid using a prosthesis” (OR 1.254, CI 1.039, 1.512), and “wake up after mastectomy with reconstruction underway” (OR 1.254, CI 1.057, 1.487). Patients who felt it was important to “avoid putting foreign material in your body” were less likely to have reconstruction (OR 0.682, CI 0.518, 0.899).The majority of patients (81%) had treatment that was concordant with preference.Conclusions: Despite reporting high involvement in decisions about reconstruction, breast cancer patients undergoing mastectomy had major knowledge deficits, and many reported having treatment they did not prefer. In addition to involving patients in decisions about reconstruction, surgeons should discuss both the pros and the cons and should explicitly ask patients for their preference about reconstruction.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3103.

Hepatobiliary abnormalities in patients with metastatic cancer treated with lapatinib

1043

Background: Lapatinib (LAP), a dual tyrosine kinase inhibitor (TKI), is effective in the treatment of HER-2-positive metastatic breast cancer. Liver toxicity has been reported as a side effect of several TKIs. We analyzed the liver safety of LAP using available data from 16 metastatic cancer trials. Methods: LAP (as monotherapy or in combination) was administered to 2,968 patients (pts) in metastatic cancer trials. Liver function tests were prospectively evaluated. We defined liver toxicity events as either NCI CTCAE grade (Gr) 3 or 4 alanine and aspartate aminotransaminases (ALT/AST) or meeting Hy's Law criteria (liver injury with jaundice). Results: Overall Gr 3 and 4 ALT/AST events were seen in 45/2,968 (1.5%) and 2/2,968 (0.07%) pts, respectively. Of LAP monotherapy pts, Gr 3 and 4 ALT/AST was seen in 13/1,470 (0.9%) and 1/1,470 (0.07%), respectively. Of LAP + monoclonal antibody (mAb) pts (trastuzumab or bevacizumab), Gr 3 and 4 ALT/AST was seen in 2/199 (1.0%) and 1/199 (0.5%), respectively. Ten of 645 pts (1.6%) treated with LAP + chemotherapy (capecitabine or paclitaxel) had Gr 3 ALT/AST. Twenty of 654 pts (3%) treated with LAP + letrozole had Gr 3 ALT/AST. Among 2,968 pts, Hy's law toxicity occurred in 8 (0.3%) pts: 2/1,470 (0.14%) pts treated with LAP alone, 1/199 (0.5%) pts treated with LAP + mAb, 4/645 (0.6%) pts treated with LAP + chemotherapy, and 1/654 (0.2%) pts treated with LAP + letrozole. Alternative causes of liver toxicity such as metastatic liver disease, infectious hepatitis, and heart failure will be reported at the meeting. Conclusions: Review of data from 16 clinical trials in metastatic cancer revealed low levels of liver toxicity for LAP. Oncologists should be vigilant for this rare side effect of LAP. A proposed monitoring algorithm of symptom assessment and frequency of hepatobiliary laboratory monitoring will be shown.

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NCIC CTG MA.17: hormone receptor expression of in-breast recurrences and contralateral primary breast cancers arising on aromatase inhibitors

Abstract #1134

Background: The selective estrogen receptor modulators (SERMs) tamoxifen and raloxifene reduce the risk of ER+ (but not ER-) invasive breast cancers in healthy women at high risk for developing breast cancer. Aromatase inhibitors (AIs) given as adjuvant therapy to treatment-naïve or post-tamoxifen patients significantly reduce the risk of in-breast recurrences (IBRs) and contralateral breast cancers (CBCs) and are currently in clinical trials for breast cancer prevention (NCIC CTG MAP.3 and IBIS-II). It is hypothesized that SERMS inhibit promotion of ER+ breast cancer whereas AIs may reduce both ER+ and ER- breast cancer by inhibiting both tumor initiation and promotion. Little is known about the characteristics of IBRs and CBCs that arise on AI therapy. We present the ER/PR expression and clinicopathologic features of IBRs and CBCs that occurred on MA.17.
 Methods: We examined ER/PR status of IBRs and CBCs that arose on letrozole vs. placebo among women enrolled in MA.17, a placebo-controlled (PLAC) trial of letrozole (LET) following 5 years of tamoxifen in postmenopausal women with early stage breast cancer.
 Results: Seventy-one patients (pts) developed an IBR and 87 developed a CBC on trial. Consistent with results previously reported, fewer IBRs (LET 20 vs PLAC 51) and CBCs (LET 35 vs PLAC 52) were observed in the LET group. ER and PR status is currently available on 35 women with an IBR and 39 with a CBC. The majority of IBRs were ER+ in both the LET and PLAC groups (10/11 [91%] vs 18/24 [75%], respectively; p=NS) but numbers of both ER+ and – IBRs were less in LET group, suggesting that letrozole may decrease both ER+ and ER- IBRs. CBCs that arose on PLAC were more likely to be ER+ than on LET (16/22 [73%] vs 6/19 pts [32%], respectively; p=0.01), suggesting that letrozole predominantly prevents ER+ CBCs. Discordance in ER expression between primary breast cancer and IBRs among women randomized to LET vs. PLAC was observed in 1/11 [9%] and 6/24 [26%] women respectively (p=NS) and between primary breast cancer and CBCs in 12/18 pts [67%] vs. 6/21 [29%] women respectively (p=0.01). Other clinicopathologic characteristics such as grade, tumor size, PR, HER-2/neu, and nodal status of IBRs and CBCs will be presented at the meeting.
 Conclusion: Extended adjuvant endocrine therapy with letrozole results in fewer IBRs and CBCs compared with placebo as previously reported. Our data suggests that letrozole may decrease both ER+ and ER- IBRs. Letrozole appears to prevent ER+ CBCs but has little or no apparent effect on the development of ER- CBCs. These results need confirmation in the primary prevention trials of AIs.
 


Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1134.

Dose-dense (DD) doxorubicin and cyclophosphamide (AC) followed by weekly paclitaxel (P) with trastuzumab (T) and lapatinib (L) in HER2/neu-positive breast cancer is not feasible due to excessive diarrhea: updated results

Abstract #2108

Background: DD q 2 weekly (w) AC → P + T x 1 year (y) has an acceptable safely profile w/ congestive heart failure (CHF) rate of 1/70 pts (Dang, JCO 2008). Lapatinib (L) is effective in HER2 (+) BC. We conducted a pilot study of dd AC → w P + T + L to determine its feasibility and cardiac safety.
 Methods: Enrolled pts had HER2 (+) BC; LVEF > 50%. Rx consisted of AC at 60/600 mg/m2 x 4 q 2 w (w/ pegfilgrastim 6 mg day 2) → P at 80 mg/m2 x 12 q w + T x 1 y; L (1000 mg daily beginning w/ P + T and continued x 1 y). MUGA is obtained at baseline and at months (mo) 2, 6, 9, and 18. Rx is considered feasible if 1) > 80% pts can complete the PTL phase without a dose delay or reduction and 2) the cardiac event rate (CHF or cardiac death) is < 4%. Pts can remain on-Rx w/ one dose reduction of L (1000 mg → 750 mg) for a G 3 event or < G 3 toxicity (unacceptable).
 Results: From March 2007 to April 2008, we enrolled 95 pts. Median (med) age was 45 years (range, 28-73). At a med follow-up of 7 months, 90 are evaluable. Of the 90 pts, 34 (37%) withdrew from study during the PTL phase; 29 for a 2nd event of G 3 or unacceptable < G 3 toxicities (15 G 3 diarrhea, 4 G 1/2 diarrhea, 1 G 3 rash, 2 G 2 rash, 1 G 3 dyspnea and also had G 3 diarrhea, 1 G 3 ↑QTc also had G 3 diarrhea, 1 G 3 ↑ALT also had G 3 diarrhea, 1 G 3 paronychia, 1 G 3 pneumonitis, 1 asymptomatic LVEF ↓, 1 myocarditis) and 5 for other reasons (2 personal reason, 1 PCP pneumonia, 1 progression, 1 P hypersensitivity). Overall, 25/90 (27%) pts had G 3 diarrhea and 31/90 (34%) pts required a dose reduction of lapatinib. Med LVEF at baseline is 67% (N=95), at mo 2 is 68% (N=90), at mo 6 is 65% (N=53), and mo 9 is 65% (N=28). To date there are no patient drop-outs due to significant LVEF declines after dd AC; one patient dropped during PTL out due to an asymptomatic LVEF decline.
 Discussion: L at 1000 mg/day is not feasible combined w/ weekly P and T by protocol stipulation (> 20% pts required L dose reduction) primarily due to excessive G 3 diarrhea. These results have led to the modification of Design 2 (Arm D) of ALTTO. We will report updated results.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2108.