Ribociclib plus Endocrine Therapy in Early Breast Cancer

BACKGROUND

Ribociclib has been shown to have a significant overall survival benefit in patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer. Whether this benefit in advanced breast cancer extends to early breast cancer is unclear.

METHODS

In this international, open-label, randomized, phase 3 trial, we randomly assigned patients with HR-positive, HER2-negative early breast cancer in a 1:1 ratio to receive ribociclib (at a dose of 400 mg per day for 3 weeks, followed by 1 week off, for 3 years) plus a nonsteroidal aromatase inhibitor (NSAI; letrozole at a dose of 2.5 mg per day or anastrozole at a dose of 1 mg per day for ≥5 years) or an NSAI alone. Premenopausal women and men also received goserelin every 28 days. Eligible patients had anatomical stage II or III breast cancer. Here we report the results of a prespecified interim analysis of invasive disease-free survival, the primary end point; other efficacy and safety results are also reported. Invasive disease-free survival was evaluated with the use of the Kaplan-Meier method. The statistical comparison was made with the use of a stratified log-rank test, with a protocol-specified stopping boundary of a one-sided P-value threshold of 0.0128 for superior efficacy.

RESULTS

As of the data-cutoff date for this prespecified interim analysis (January 11, 2023), a total of 426 patients had had invasive disease, recurrence, or death. A significant invasive disease-free survival benefit was seen with ribociclib plus an NSAI as compared with an NSAI alone. At 3 years, invasive disease-free survival was 90.4% with ribociclib plus an NSAI and 87.1% with an NSAI alone (hazard ratio for invasive disease, recurrence, or death, 0.75; 95% confidence interval, 0.62 to 0.91; P = 0.003). Secondary end points - distant disease-free survival and recurrence-free survival - also favored ribociclib plus an NSAI. The 3-year regimen of ribociclib at a 400-mg starting dose plus an NSAI was not associated with any new safety signals.

CONCLUSIONS

Ribociclib plus an NSAI significantly improved invasive disease-free survival among patients with HR-positive, HER2-negative stage II or III early breast cancer. (Funded by Novartis; NATALEE ClinicalTrials.gov number, NCT03701334.).

Pooled ctDNA analysis of MONALEESA phase III advanced breast cancer trials

BACKGROUND

The phase III MONALEESA trials tested the efficacy and safety of the cyclin-dependent kinase (CDK)4/6 inhibitor ribociclib with different endocrine therapy partners as first- or second-line treatment of hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer (ABC). Using the largest pooled biomarker dataset of the CDK4/6 inhibitor ribociclib in ABC to date, we identified potential biomarkers of response to ribociclib.

PATIENTS AND METHODS

Baseline circulating tumour DNA from patients in the MONALEESA trials was assessed using next-generation sequencing. An analysis of correlation between gene alteration status and progression-free survival (PFS) was carried out to identify potential biomarkers of response to ribociclib.

RESULTS

Multiple frequently altered genes were identified. Alterations in ERBB2, FAT3, FRS2, MDM2, SFRP1, and ZNF217 were associated with a greater PFS benefit with ribociclib versus placebo. Patients with high tumour mutational burden (TMB) and with ANO1, CDKN2A/2B/2C, and RB1 alterations exhibited decreased sensitivity to ribociclib versus placebo.

CONCLUSIONS

Although exploratory, these results provide insight into alterations associated with the improved response to ribociclib treatment and may inform treatment sequencing in patients with actionable alterations following progression on CDK4/6 inhibitors. Validation of potential biomarkers identified here and development of prospective trials testing their clinical utility are warranted.

CLINICALTRIALS

GOV IDENTIFIERS

NCT01958021, NCT02422615, NCT02278120.

Absence of lobular carcinoma in situ is a poor prognostic marker in invasive lobular carcinoma

AIM

To determine if the outcomes of patients with ILC co-occurring with LCIS are similar to pure ILC and if the presence of LCIS is a prognostic factor for ILC.

METHODS

In an observational, population-based investigation using data from the MD Anderson breast cancer prospectively collected electronic database, we analysed patients with a diagnosis of stage I-III ILC. Patients were divided into two groups: those with ILC with co-occurring ipsilateral LCIS (ILC + LCIS) and those with pure ILC without a histologically detected co-occurring ipsilateral LCIS (ILC alone). We obtained data on demographics, pathologic tumour size (pT), pathologic lymph node (pN) involvement, estrogen (ER), progesterone (PR) receptor status, HER2 status, Ki67, treatment received, distant recurrence-free and overall survival (DRFS, OS).

RESULTS

We identified 4217 patients with stage I-III ILC treated at MD Anderson between 1966 and 2021. 45% of cases (n = 1881) had co-existing LCIS. Statistically and numerically, ILC alone tended to associate with pT4 and pN3 stage (P < 0.001), ER/PR negativity (P = 0.0002), HER2 positivity (P = 0.010), higher Ki67 (P = 0.005), non-classical ILC subtype (P = 0.04) and more exposure to neoadjuvant chemotherapy (P = 0.0002) compared to the ILC + LCIS group. The median follow-up time was 6.5 years. Patients with ILC + LCIS had better median DRFS (16.8 versus 10.1 years, Hazard ratio [HR] 0.55, 95% confidence interval [CI] 0.50-0.60, P < 0.0001) and better median OS (18.9 versus 13.7 years, HR 0.62, 95% CI 0.56-0.69; P < 0.0001). Multivariate analysis showed the absence of LCIS to be an independent poor prognostic factor along with a higher pT stage and higher pN stage for DRFS and OS.

CONCLUSION

The findings of this study suggests that the absence of ipsilateral LCIS with ILC is an independent poor prognostic factor and that further studies are warranted to understand this phenomenon.

Tucatinib vs Placebo, Both in Combination With Trastuzumab and Capecitabine, for Previously Treated ERBB2 (HER2)-Positive Metastatic Breast Cancer in Patients With Brain Metastases: Updated Exploratory Analysis of the HER2CLIMB Randomized Clinical Trial

Importance

It is estimated that up to 50% of patients with ERBB2 (HER2)-positive metastatic breast cancer (MBC) will develop brain metastases (BMs), which is associated with poor prognosis. Previous reports of the HER2CLIMB trial have demonstrated that tucatinib in combination with trastuzumab and capecitabine provides survival and intracranial benefits for patients with ERBB2-positive MBC and BMs.

Objective

To describe overall survival (OS) and intracranial outcomes from tucatinib in combination with trastuzumab and capecitabine in patients with ERBB2-positive MBC and BMs with an additional 15.6 months of follow-up.

Design, Setting, and Participants

HER2CLIMB is an international, multicenter, randomized, double-blind, placebo-controlled clinical trial evaluating tucatinib in combination with trastuzumab and capecitabine. The 612 patients, including those with active or stable BMs, had ERBB2-positive MBC previously treated with trastuzumab, pertuzumab, and trastuzumab emtansine. The study was conducted from February 23, 2016, to May 3, 2019. Data from February 23, 2016, to February 8, 2021, were analyzed.

Interventions

Patients were randomized 2:1 to receive tucatinib (300 mg orally twice daily) or placebo (orally twice daily), both in combination with trastuzumab (6 mg/kg intravenously or subcutaneously every 3 weeks with an initial loading dose of 8 mg/kg) and capecitabine (1000 mg/m2 orally twice daily on days 1-14 of each 3-week cycle).

Main Outcomes and Measures

Evaluations in this exploratory subgroup analysis included OS and intracranial progression-free survival (CNS-PFS) in patients with BMs, confirmed intracranial objective response rate (ORR-IC) and duration of intracranial response (DOR-IC) in patients with measurable intracranial disease at baseline, and new brain lesion-free survival in all patients. Only OS was prespecified before the primary database lock.

Results

At baseline, 291 of 612 patients (47.5%) had BMs. Median age was 52 years (range, 22-75 years), and 289 (99.3%) were women. At median follow-up of 29.6 months (range, 0.1-52.9 months), median OS was 9.1 months longer in the tucatinib-combination group (21.6 months; 95% CI, 18.1-28.5) vs the placebo-combination group (12.5 months; 95% CI, 11.2-16.9). The tucatinib-combination group showed greater clinical benefit in CNS-PFS and ORR-IC compared with the placebo-combination group. The DOR-IC was 8.6 months (95% CI, 5.5-10.3 months) in the tucatinib-combination group and 3.0 months (95% CI, 3.0-10.3 months) in the placebo-combination group. Risk of developing new brain lesions as the site of first progression or death was reduced by 45.1% in the tucatinib-combination group vs the placebo-combination group (hazard ratio, 0.55 [95% CI, 0.36-0.85]).

Conclusions and Relevance

This subgroup analysis found that tucatinib in combination with trastuzumab and capecitabine improved OS while reducing the risk of developing new brain lesions, further supporting the importance of this treatment option for patients with ERBB2-positive MBC, including those with BMs.

Trial Registration

ClinicalTrials.gov Identifier: NCT02614794.

Surrogacy of Pathologic Complete Response in Trials of Neoadjuvant Therapy for Early Breast Cancer: Critical Analysis of Strengths, Weaknesses, and Misinterpretations

Importance

The pathologic complete response (pCR) is supported by regulatory agencies as a surrogate end point for long-term patients' clinical outcomes in the accelerated approval process of new drugs tested in neoadjuvant randomized clinical trials (RCTs) for early breast cancer (BC). However, a meaningful association between pCR and patients' survival has been proven only at the patient level (ie, significantly better survival of patients who achieved pCR compared with those who did not), but not at trial level (ie, poor association between degree of improvement in pCR rate and survival reported across trials).

Observations

We critically discuss the potential reasons of such discrepancy between pCR surrogacy value at the patient and trial level, as well as the relevant implications for both clinical research and drug regulatory policy. We also describe alternative surrogate end points, including combined end points that jointly analyzed pathological response and event-free survival data, or the assessment of circulating tumor DNA (ctDNA). Such proposed surrogate end points could overcome limits of pCR and provide a reasonable trade-off between the 2 conflicting needs to have access to effective therapies rapidly, and to reliably assess patients' clinical benefit.

Conclusions and Relevance

Using surrogate end points to grant drug approvals is justified only when they can provide accurate prediction of a drug's effect on the long-term patient outcomes. Evidence currently available does not support pCR used alone as a reliable surrogate end point in regulatory neoadjuvant RCTs for BC. The surrogacy value at trial level of potentially more robust surrogate end points needs to be urgently tested.

Abstract GS2-07: Updated results from a phase 3 randomized clinical trial in participants (pts) with 1-3 positive lymph nodes (LN), hormone receptor-positive (HR+) and HER2-negative (HER2-) breast cancer (BC) with recurrence score (RS) ≤ 25 randomized to endocrine therapy (ET) +/- chemotherapy (CT): SWOG S1007 (RxPONDER)

Background: We previouslyreported that invasive disease-free survival (IDFS), the primary outcome, and distantdisease-free survival (DDFS), a secondary outcome, differed by menopausalstatus in a pre-specified analysis. Here,we report updates on IDFS and DDFS with additional follow-up, as well as distantrecurrence-free interval (DRFI) and post hoc analyses in premenopausal women.Methods: Eligibilitycriteria included women &gt; 18 years of age with HR+, HER2-BC and 1-3 +LN and no contraindications to taxane and/or anthracycline basedCT. DRFI was defined as time to distant recurrence or death from breast cancer.Analyses were intent-to-treat among eligible pts. We performed a post hocanalysis evaluating IDFS between treatment arms in premenopausal pts with pN1mi.In addition, we conducted a two-year landmarked IDFS analysis by ovarianfunction suppression (OFS) or not in the ET arm, as well as by regularmenstrual periods or not in both treatment arms.Results: Among the 4,984eligible pts, there were 553 IDFS events and median follow-up of 6.1 years.Postmenopausal women do not have any IDFS or DDFS benefit with CT; however, 5-yearabsolute benefits for IDFS and DDFS with CT for premenopausal pts were 5.9% and3.3%, respectively. In pre-menopausal pts, CT was associated with improved DRFIfor all RS values &lt; 25, with an absolute improvement of 2.3% for RS0-13 and of 2.8% for RS 14-25. Among premenopausal pts, 12.4% (n=206) had pNmi)disease. In a post hoc analysis, there was a trend for CT benefit for thosewith pNmi [hazard ratio (HR)=0.44, confidence interval (CI)=0.18-1.08]. Therewere only 22 IDFS events. Only 17.2% of premenopausal pts assigned to ETunderwent OFS in the first 24 months and in two-year landmarked analysis, therewas no IDFS difference in those who underwent OFS or not (HR=0.88,CI=0.47-1.63). In premenopausal women assigned to ET, 58.9% stopped havingperiods within the first 24 months, and have anumerically improved IDFS compared to those who continued regular periods (HR=1.48,CI: 0.92-2.40). Among premenopausal assigned to CT followed by ET, 80.8%stopped having periods within the first 24 months and have a numericallyimproved IDFS compared to those who continue to have regular periods (HR=1.56, CI:0.85-2.86).Discussion: In accordancewith the differential IDFS and DDFS benefit based upon menopausal status inS1007, premenopausal pts with 1-3+LN and RS &lt; 25 had a statisticallysignificant improvement in DRFI with the addition of CT. A small proportion of S1007premenopausal participants underwent OFS. The role of OFS as it relates to CTbenefit cannot be determined from this study. A future randomized trial should address the clinical question if OFScan replace CT in premenopausal pts with HR+/HER2-, node-positive breast cancer.Funding: Supported by National Cancer Institute grants U10CA180888, U10CA180819,U10CA180820, U10CA180821, U10CA180868, U10CA180863, and in part by Susan G.Komen for the Cure® Research Program, The Hope Foundation for Cancer Research,Breast Cancer Research Foundation, and Genomic Health, Inc.

Citation Format: Kevin M Kalinsky, William E Barlow, Julie R Gralow, Funda Meric-Bernstam, Kathy S Albain, Daniel F Hayes, Nancy U Lin, Edith A Perez, Lori A Goldstein, Stephen KL Chia, Sukhbinder Dhesy-Thind, Priya Rastogi, Emilio Alba, Suzette Delaloge, Miguel Martin, Catherine M Kelly, Manuel Ruiz-Borrego, Miguel Gil-Gil, Claudia H Arce-Salinas, Etienne GC Brain, Eun Sook Lee, Jean-Yves Pierga, Begoña Bermejo, Manuel Ramos-Vasquez, Kyung Hae Jung, Jean-Marc Ferrero, Anne Schott, Steven Shak, Priyanka Sharma, Danika Lew, Jieling Miao, Debasish Tripathy, Lajos Pusztai, Gabriel Hortobagyi. Updated results from a phase 3 randomized clinical trial in participants (pts) with 1-3 positive lymph nodes (LN), hormone receptor-positive (HR+) and HER2-negative (HER2-) breast cancer (BC) with recurrence score (RS) ≤ 25 randomized to endocrine therapy (ET) +/- chemotherapy (CT): SWOG S1007 (RxPONDER) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr GS2-07.

Abstract PD4-04: Updated results of tucatinib vs placebo added to trastuzumab and capecitabine for patients with previously treated HER2-positive metastatic breast cancer with brain metastases (HER2CLIMB)

Background: Tucatinib is an oral tyrosine kinase inhibitor highly specific for HER2 that is approved for use in combination with trastuzumab and capecitabine in adults with advanced or metastatic HER2+ breast cancer, including patients with brain metastases, who have received one or more prior anti-HER2-based regimens in the metastatic setting. In the HER2CLIMB trial, the tucatinib regimen significantly prolonged progression-free survival (PFS) and overall survival (OS) in patients with HER2+ metastatic breast cancer (Murthy, NEJM 2020), including in patients with untreated, treated stable, and treated progressing brain metastases (Lin, J Clin Oncol, 2020). With an additional 15.6 months of follow-up, addition of tucatinib continued to show clinically meaningful prolongation of PFS and OS in the total study population (Curigliano, ASCO Meeting, 2021). We report updated results of exploratory efficacy analyses in patients with brain metastases. Methods: All patients in HER2CLIMB had a baseline brain MRI. Patients with brain metastases were eligible and classified as untreated, treated stable, or treated progressing. Patients were randomized 2:1 to receive tucatinib 300 mg twice daily or placebo, in combination with trastuzumab and capecitabine. Following the primary analysis, the protocol was amended to unblind sites to treatment assignment and allowed crossover from the placebo regimen to the tucatinib regimen. Efficacy analyses in patients with brain metastases at baseline were performed at approximately 2 years from the last patient randomized by applying RECIST 1.1 to the brain based on investigator evaluation. OS and CNS-PFS (progression in the brain or death) were evaluated in all patients with brain metastases. Patients without CNS-PFS events were censored at the last brain MRI. Confirmed intracranial (IC) objective response rate (ORR-IC) was evaluated in patients with measurable IC disease. Results: At a median follow-up of 29.6 months, median OS was 21.6 months vs 12.5 months in all patients with brain metastases (HR: 0.60; 95% CI: 0.44, 0.81), 21.4 months vs 11.8 months in patients with untreated/treated progressing brain metastases (HR: 0.52; 95% CI: 0.36, 0.77), and 21.6 months vs 16.4 months in patients with treated stable brain metastases (HR: 0.70; 95% CI: 0.42, 1.16). Median CNS-PFS was 9.9 months vs 4.2 months in all patients with brain metastases (HR: 0.39; 95% CI: 0.27, 0.56), 9.6 months vs 4.0 months in patients with untreated/treated progressing brain metastases (HR: 0.34; 95% CI: 0.22, 0.54), and 13.9 months vs 5.6 months in patients with treated stable brain metastases (HR: 0.41; 95% CI: 0.19, 0.85). ORR-IC was higher in the tucatinib arm (47.3%; 95% CI: 33.7, 61.2) vs the placebo arm (20.0%; 95% CI: 5.7, 43.7) for patients with brain metastases, and median duration of response (DOR) was 8.6 months (95% CI: 5.5, 10.3) vs 3.0 months (95% CI: 3.0, 10.3). Conclusions: With 15.6 months of additional follow-up, the tucatinib-trastuzumab-capecitabine regimen resulted in a robust and durable prolongation of OS for all patients with HER2+ metastatic breast cancer and brain metastases. Additionally, this benefit was maintained in patients with untreated/treated progressing and treated stable brain metastases. Treatment with tucatinib continued to show clinically meaningful benefit in CNS-PFS consistent with the primary analysis.

Citation Format: Nancy U Lin, Rashmi K Murthy, Vandana Abramson, Carey Anders, Thomas Bachelot, Philippe Bedard, Virginia Borges, David Cameron, David Cameron, Lisa Carey, A Jo Chien, Giuseppe Curigliano, Michael DiGiovanna, Karen Gelmon, Gabriel Hortobagyi, Sara Hurvitz, Ian Krop, Sherene Loi, Sibylle Loibl, Volkmar Mueller, Mafalda Oliveira, Elisavet Paplomata, Mark Pegram, Dennis Slamon, Amelia Zelnak, Jorge Ramos, Wentao Feng, Eric Winer. Updated results of tucatinib vs placebo added to trastuzumab and capecitabine for patients with previously treated HER2-positive metastatic breast cancer with brain metastases (HER2CLIMB) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD4-04.

Impact of Merit-Based Immigration Policies on Brain Drain From Low- and Middle-Income Countries

PURPOSE

Brain drain is the migration of educated and skilled individuals from a less developed region or country to a more economically established one. The Trump administration proposed a merit-based immigration plan. This article addresses its potential impact on health care delivery in low- and middle-income countries (LMICs) and their preparedness to deal with it.

MATERIALS AND METHODS

Data on immigration policies, numbers of international medical graduates practicing in high-income countries (HICs), various scientific exchange methods, and efforts for capacity building in LMICs.

RESULTS

Talented individuals seek to advance their knowledge and skills, and may stay in HICs because of greater rewards and opportunities. HICs also rely on immigrant international medical graduates to supplement their physician workforces.

CONCLUSION

Ambitious individuals from LMICs need and should have opportunities to advance their education and training in more advanced countries. LMICs should increase their educational efforts, research capabilities, infrastructures, and living conditions to better serve their own populations and reduce their brain drain phenomenon.

Abstract GS3-00: First results from a phase III randomized clinical trial of standard adjuvant endocrine therapy (ET) +/- chemotherapy (CT) in patients (pts) with 1-3 positive nodes, hormone receptor-positive (HR+) and HER2-negative (HER2-) breast cancer (BC) with recurrence score (RS) &lt; 25: SWOG S1007 (RxPonder)

Funding: Supported by National Cancer Institute grants U10CA180888, U10CA180819, U10CA180820, U10CA180821, U10CA180868, U10CA180863; and in part by Susan G. Komen for the Cure® Research Program, The Hope Foundation for Cancer Research, Breast Cancer Research Foundation, and Genomic Health, Inc. Acknowledgement: The authors wish to thank Dr. Ana M. Gonzalez-Angulo, MD, for her invaluable contributions to the design and implementation of this study. Background: The clinical utility of the RS to determine CT benefit is well established in pts with HR+, HER2-, axillary lymph node (LN)-negative BC. Retrospective analyses from SWOG S8814 support the potential prognostic and predictive role of RS for CT benefit in postmenopausal pts with LN+ BC. SWOG S1007 is a prospective, randomized trial of endocrine therapy (ET) vs. chemoendocrine therapy (CET) in women with 1-3 +LN and a RS &lt; 25 (NCT01272037). Methods: Eligibility criteria included women &gt; 18 years of age with HR+, HER2- BC and 1-3 +LN and no contraindications to taxane and/or anthracycline based CT. Women with a RS &lt; 25 were randomized to receive ET or CET in 1:1 randomization using 3 stratification factors: (1) RS (0-13 vs.14-25); (2) menopausal status; and (3) axillary nodal dissection vs. sentinel node biopsy. The primary objective was to determine the effect of CT on invasive disease-free survival (IDFS) and whether the effect depended on the RS. The primary analysis was to test for a significant interaction of the treatment arm and continuous RS using a Cox regression model for IDFS, adjusting for treatment, RS, and menopausal status. A total of 832 IDFS events were expected for the final analysis. Secondary objectives included overall survival (OS). The protocol specified that interaction between treatment and the stratification variables was to be tested and, if significant, separate analyses performed by stratum. Annual interim analyses were planned starting at 24% of events. At the third interim analysis with 410 IDFS events, the Data and Safety Monitoring Committee recommended reporting results, with a decision by the NCI’s Cancer Therapy Evaluation Program, the study sponsor. Results: Of the 9,383 women screened from 2/28/11-9/29/17, 5,083 pts (54.2%) were randomized. With a median follow-up of 5.1 years, 447 IDFS events have been observed. For the primary analysis, the interaction test for CT benefit and continuous RS was not statistically significant, p=0.30. In a model with CT, RS, and menopausal status (no interaction term), higher continuous RS was associated with worse IDFS [HR 1.06, 2-sided p&lt;0.001, 95% Confidence Interval (CI) 1.04-1.07], and CT was associated with an improvement in IDFS (HR 0.81, p=0.026, 95% CI 0.67-0.98). In a pre-specified analysis, a significant interaction was identified between CT and menopausal status (p=0.004), necessitating separate analyses by menopausal status. In postmenopausal pts (N=3350, 67%), adjusting for continuous RS, the HR for CET vs. ET was not significant (HR=0.97, p=0.82, 95% CI 0.78-1.22; 5-year IDFS 91.6% vs. 91.9%) indicating no benefit from CT. In premenopausal pts (N=1665, 33%), the HR (0.54) was statistically significant (p=0.0004, 95% CI 0.38-0.76; 5-year IDFS 94.2% vs. 89.0%), indicating CT benefit. In premenopausal pts, ovarian suppression was performed in 15.9% vs. 3.7% (ET vs. CET), and 47.9% vs. 26.4% reported menstruation after 6 months of treatment. Although the number of events is limited, the HR for treatment adjusted by RS for OS in premenopausal pts was 0.47 (p=0.032, 95% CI 0.24-0.94). At this time, there is no differential effect with CT in regard to other stratification factors. Conclusions: There is a significant differential treatment effect of CT benefit based on RS for premenopausal vs. postmenopausal women requiring separate analyses. While only 54% of the protocol specified events are recorded and pts will be followed for 15 years, the current data show that adjuvant therapy can be de-escalated to ET alone in postmenopausal pts with a RS &lt; 25 and 1-3 +LN. However, there is a strong IDFS benefit for CET in premenopausal pts, with an early indication of an OS improvement.

Citation Format: Kevin Kalinsky, William E Barlow, Funda Meric-Bernstam, Julie R Gralow, Kathy S Albain, Daniel Hayes, Nancy Lin, Edith A Perez, Lori J Goldstein, Stephen Chia, Subkhbinder Dhesy-Thind, Priya Rastogi, Emilio Alba, Suzette Delaloge, Miguel Martín, Miguel Gil Gil, Claudia Arce-Salinas, Etienne Brain, In Hae Park, Jean-Yves Pierga, Ana Hernandez Lluch, Manuel Ramos Vasquez, Manuel Ruiz Borrego, Kyung Hae Jung, Jean-Marc Ferrero, Anne Schott, Steve Shak, Priyanka Sharma, Danika L Lew, Jieling Miao, Debu Tripathy, Gabriel Hortobagyi, Lajos Pusztai. First results from a phase III randomized clinical trial of standard adjuvant endocrine therapy (ET) +/- chemotherapy (CT) in patients (pts) with 1-3 positive nodes, hormone receptor-positive (HR+) and HER2-negative (HER2-) breast cancer (BC) with recurrence score (RS) &lt; 25: SWOG S1007 (RxPonder) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr GS3-00.

Abstract PS4-05: Prospective evaluation of the gut microbiome and response to neoadjuvant therapy (NAT) in early-stage triple negative breast cancer (TNBC)

Introduction: Emerging data suggest that the gut microbial composition influences responses to chemotherapy and immunotherapy. However, similar data in patients with TNBC receiving NAT remains limited. Thus, we investigated the association between the gut microbial composition in patients with newly-diagnosed, early-stage TNBC and response to NAT in a cohort of patients enrolled in the ARTEMIS trial (NCT02276443). Methods: We performed 16S sequencing on bacterial genomic DNA extracted from pre-NAT fecal samples using the 2x250 bp paired-end read protocol. Quality-filtered sequences were clustered into Operational Taxonomic Units and classified using Mothur method with the Silva database version 128. Associations between abundance and pathologic response to NAT were assessed using the Mann Whitney U Test. A cohort of 32 patients had longitudinal samples collected. Mann-Whitney U Test and Fishers exact were used to compare clinical variables as appropriate between the pCR and non-pCR groups. Results: There was no significant difference in age, race or stage between the pCR and non-pCR groups (Table 1). As expected, the pCR group was enriched for high TIL (p=0.026). There was no difference in alpha-diversity of the gut microbiome between patients with NAT-sensitive (pCR) and NAT-resistant disease (non-pCR) (p=0.5). Relative to patients with NAT-sensitive disease (pCR), the gut microbiome in patients with NAT-resistant disease was enriched for Fusobacterium (p=0.009), Intestinimonas (p=0.01) and Lachnospiraceae (p=0.003) at the genus level; the median abundances between pCR and non-pCR are provided in Table 1. Longitudinal samples collected during NAT demonstrated no substantial impact of NAT on the gut microbiome.

Conclusions: Taken together, these data suggest that response to NAT may be influenced by the gut microbial composition, which remains unaltered during NAT. Research efforts to modulate the gut microbiome should be further explored as a potential therapeutic strategy in TNBC.

Table 1: Median Microbial Abundance and Clinicopathological Variables (N=43)pCR (n=18)Non-pCR (n=25)p- valueMicrobial AbundanceFusobacterium1 x 10-61.02 x 10-50.009Intestinimonas6.4 x 10-54.8 x 10-40.01Lachnospiraceae6.2 x 10-31.0 x 10-20.003Age median, interquartile range (n=44)45 (38-59)53 (46-58)0.61n (%)Race/EthnicityWhite, non-Hispanic11 (61.1)14 (56.0)0.53White, Hispanic4 (22.2)3 (12.0)Black2 (11.1)7 (28.0)Asian1 (5.6)1 (4.0)T categoryT15 (27.8)4 (16.0)0.15T213 (72.2)17 (68.0)T304 (16.0)T400Nodal statusNegative12 (66.7)14 (56.0)0.54Positive6 (33.3)11 (44.0)StageI3 (16.7)3 (12.0)0.91II11 (61.1)15 (60.0)III4 (22.2)7 (28.0)TIL&lt;20%7 (38.9)19 (76.0)0.026&gt;20%11 (61.1)6 (24.0)

Citation Format: Nour Abuhadra, Chia-Chi Chang, Clinton Yam, Ryan Sun, Lei Huo, Jason White, Elizabeth E Ravenberg, Jennifer Litton, Bora Lim, Naoto T Ueno, Banu Arun, Debu Tripathy, Senthil Damodaran, Rashmi Murthy, Vicente Valero, Gabriel Hortobagyi, Nuhad Ibrahim, Alastair Thompson, Elizabeth Mittendorf, Stacy Moulder, Robert Jenq. Prospective evaluation of the gut microbiome and response to neoadjuvant therapy (NAT) in early-stage triple negative breast cancer (TNBC) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS4-05.

Abstract B24: Phase II trial of AKT inhibitor MK-2206 in patients with advanced breast cancer who have tumors with PIK3CA or AKT mutations, and/or PTEN loss/PTEN mutation

Background: The PI3K/AKT pathway is activated through PIK3CA or AKT1 mutations and PTEN loss in breast cancer. We conducted a phase II trial with an allosteric AKT Inhibitor MK-2206 in patients with advanced breast cancer who had tumors with PIK3CA/AKT1 mutations and/or PTEN loss/mutation.

Methods: The primary endpoint was objective response rate (ORR). Secondary endpoints were 6-month progression-free survival (6m PFS), predictive and pharmacodynamic markers, safety and tolerability. Patients had pretreatment and on-treatment biopsies as well as collection of peripheral blood mononuclear cells (PBMC) and platelet-rich plasma (PRP). Next-generation sequencing, immunohistochemistry and reverse phase protein arrays (RPPA) were performed.

Results: Twenty-seven patients received MK-2206. Eighteen patients were enrolled into the PIK3CA/AKT1 mutation arm (cohort A): 13 had PIK3CA mutations, four had AKT1 mutations and one had a PIK3CA mutation as well as PTEN loss. ORR and 6m PFS were both 5.6% (1/18), with one patient with HR+ breast cancer and a PIK3CA E542K mutation experiencing a partial response (on treatment for 36 weeks). Nine patients were enrolled on the PTEN loss/mutation arm (cohort B). ORR was 0% and 6m PFS was 11% (1/9), observed in a patient with triple-negative breast cancer and PTEN loss. The study was stopped early due to futility. The most common adverse events were fatigue (48%) and rash (44%). On pretreatment biopsy, PIK3CA and AKT1 mutation status was concordant with archival tissue testing. However, two patients with PTEN loss based on archival testing had PTEN expression on the pretreatment biopsy. MK-2206 treatment was associated with a significant decline in pAKT S473 and pAKT T308 and PI3K activation score in PBMC and PRPs, but not in tumor biopsies. By IHC, there was no significant decrease in median pAKT S473 or Ki-67 staining, but a drop was observed in both responders.

Conclusions: MK-2206 monotherapy had limited clinical activity in advanced breast cancer patients selected for PIK3CA/AKT1 or PTEN mutations or PTEN loss. This may, in part, be due to inadequate target inhibition at tolerable doses in heavily pretreated patients with pathway activation, as well as tumor heterogeneity and evolution in markers such as PTEN conferring challenges in patient selection.

Citation Format: Yan Xing, Nancy U. Lin, Mathew Mauer, Huiqin Chen, Armeen Mahvash, Aysegul Sahin, Argun Akcakanat, Yisheng Li, Vandana Abraham, Jennifer Litton, Mariana Chavez-McGregor, Vicente Valero, Sarina A. Piha-Paul, David Hong, Kim-Anh Do, Emily Tarco, Dianna Riall, Karina Agda Eterovic, Lewis Cantley, Gordon B. Mills, L. Austin Doyle, Eric Winer, Gabriel Hortobagyi, Ana Maria Gonzalez-Angulo, Funda Meric-Bernstam. Phase II trial of AKT inhibitor MK-2206 in patients with advanced breast cancer who have tumors with PIK3CA or AKT mutations, and/or PTEN loss/PTEN mutation [abstract]. In: Proceedings of the AACR Special Conference on Targeting PI3K/mTOR Signaling; 2018 Nov 30-Dec 8; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(10_Suppl):Abstract nr B24.

Abstract GS1-01: Tucatinib vs placebo, both combined with capecitabine and trastuzumab, for patients with pretreated HER2-positive metastatic breast cancer with and without brain metastases (HER2CLIMB)

Objectives: The primary analysis from the HER2CLIMB study will describe the efficacy and safety of tucatinib, trastuzumab, and capecitabine, a treatment regimen under investigation for patients (pts) with advanced HER2+ metastatic breast cancer (BC) refractory to standard-of-care regimens.

Rationale: Fifteen to 20% of pts diagnosed with BC annually have overexpression or amplification of the HER2 receptor. While significant advances have been made in the treatment of pts with HER2+ BC, treatment of metastatic disease remains a clinical challenge for which no curative options are available. The management of HER2+ CNS metastases (which occur at any time during the disease course in 30-50% of those with HER2+ metastatic BC) remains an area of unmet clinical need. Tucatinib is an investigational, oral tyrosine kinase inhibitor (TKI) that is highly specific to HER2 with minimal inhibition of the EGFR receptor. In a Phase 1b study, tucatinib plus capecitabine and trastuzumab showed an acceptable toxicity profile and encouraging anti-tumour activity, including in pts with active brain metastases.

Methodology: In this double-blind, international, multicenter study (NCT02614794), 612 pts with locally advanced or metastatic HER2+ BC previously treated with trastuzumab, pertuzumab, and T-DM1 were randomized 2:1 to receive tucatinib (300 mg BID) or placebo, in combination with capecitabine (1000 mg/m2 BID, Days 1–14 of each 21-day cycle) and trastuzumab (6 mg/kg once every 21 days). Pts with newly diagnosed, progressing, or stable brain metastases not requiring immediate local therapy were included. The primary endpoint is PFS per RECIST 1.1 by blinded independent central review for the first 480 pts enrolled. Secondary endpoints, including PFS in pts with brain metastases and OS, will be evaluated in all 612 pts. The primary and key secondary endpoints will be compared between treatment arms using a stratified log rank test; the hazard ratio from Cox regression model will also be reported.

Anticipated Results: Baseline demographics and disease characteristics will be presented by treatment arms. PFS, response rates, and duration of response for pts receiving tucatinib vs placebo will be reported for the first 480 pts. Common AEs and SAEs will be reported for both treatment arms in all treated pts. Secondary objectives, including PFS in pts with brain metastases and OS, may be presented if the data are sufficiently mature.

Citation Format: Rashmi Murthy, Sherene Loi, Alicia Okines, Elisavet Paplomata, Erika Hamilton, Sara Hurvitz, Nancy Lin, Virginia Borges, Vandana Gupta Abramson, Carey Anders, Philippe L Bedard, Mafalda Oliveira, Erik Jakobsen, Thomas Bachelot, Shlomit S Shachar, Volkmar Mueller, Sofia Braga, Francois P Duhoux, Richard Greil, David Cameron, Lisa Carey, Giuseppe Curigliano, Karen Gelmon, Gabriel Hortobagyi, Ian Krop, Sibylle Loibl, Mark Pegram, Dennis Slamon, Maria Corinna Palanca-Wessels, Luke Walker, Wentao Feng, Eric Winer. Tucatinib vs placebo, both combined with capecitabine and trastuzumab, for patients with pretreated HER2-positive metastatic breast cancer with and without brain metastases (HER2CLIMB) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr GS1-01.

Tucatinib, Trastuzumab, and Capecitabine for HER2-Positive Metastatic Breast Cancer

BACKGROUND

Patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer who have disease progression after therapy with multiple HER2-targeted agents have limited treatment options. Tucatinib is an investigational, oral, highly selective inhibitor of the HER2 tyrosine kinase.

METHODS

We randomly assigned patients with HER2-positive metastatic breast cancer previously treated with trastuzumab, pertuzumab, and trastuzumab emtansine, who had or did not have brain metastases, to receive either tucatinib or placebo, in combination with trastuzumab and capecitabine. The primary end point was progression-free survival among the first 480 patients who underwent randomization. Secondary end points, assessed in the total population (612 patients), included overall survival, progression-free survival among patients with brain metastases, confirmed objective response rate, and safety.

RESULTS

Progression-free survival at 1 year was 33.1% in the tucatinib-combination group and 12.3% in the placebo-combination group (hazard ratio for disease progression or death, 0.54; 95% confidence interval [CI], 0.42 to 0.71; P<0.001), and the median duration of progression-free survival was 7.8 months and 5.6 months, respectively. Overall survival at 2 years was 44.9% in the tucatinib-combination group and 26.6% in the placebo-combination group (hazard ratio for death, 0.66; 95% CI, 0.50 to 0.88; P = 0.005), and the median overall survival was 21.9 months and 17.4 months, respectively. Among the patients with brain metastases, progression-free survival at 1 year was 24.9% in the tucatinib-combination group and 0% in the placebo-combination group (hazard ratio, 0.48; 95% CI, 0.34 to 0.69; P<0.001), and the median progression-free survival was 7.6 months and 5.4 months, respectively. Common adverse events in the tucatinib group included diarrhea, palmar-plantar erythrodysesthesia syndrome, nausea, fatigue, and vomiting. Diarrhea and elevated aminotransferase levels of grade 3 or higher were more common in the tucatinib-combination group than in the placebo-combination group.

CONCLUSIONS

In heavily pretreated patients with HER2-positive metastatic breast cancer, including those with brain metastases, adding tucatinib to trastuzumab and capecitabine resulted in better progression-free survival and overall survival outcomes than adding placebo; the risks of diarrhea and elevated aminotransferase levels were higher with tucatinib. (Funded by Seattle Genetics; HER2CLIMB ClinicalTrials.gov number, NCT02614794.).

Abstract P6-18-05: First-line ribociclib + endocrine therapy in hormone receptor-positive, HER2-negative advanced breast cancer: A pooled efficacy analysis

Background: In three separate Phase III randomized, placebo-controlled trials, ribociclib (RIB; cyclin-dependent kinase 4/6 inhibitor) + various endocrine therapy (ET) partners prolonged progression-free survival (PFS) vs placebo (PBO) + ET in patients (pts) with hormone receptor-positive (HR+), HER2-negative (HER2–) advanced breast cancer (ABC). Here we further evaluate the efficacy of RIB-based regimens of interest (i.e. with a non-steroidal aromatase inhibitor [NSAI] or fulvestrant [FUL]) in pts who were ET-naïve in the ABC setting, using pooled data from three Phase III trials: MONALEESA (ML)-2 (NCT01958021; all pts), ML-3 (NCT02422615; no prior ET for ABC subgroup only), and ML-7 (NCT02278120; RIB + NSAI subgroup only).

Methods: Postmenopausal pts with no prior ET for ABC received RIB (600 mg/day; 3-weeks-on/1-week-off) or PBO + either letrozole (2.5 mg/day) in ML-2 or FUL (500 mg every 28 days, with an additional dose on Day 15 of Cycle 1) in ML-3. In ML-7, premenopausal pts with no prior ET and ≤1 line of chemotherapy for ABC received RIB or PBO + goserelin (3.6 mg every 28 days) + NSAI (anastrozole [1 mg/day]/letrozole [2.5 mg/day]). The primary endpoint of all three trials was locally assessed PFS. Secondary endpoints included overall response rate (ORR), clinical benefit rate (CBR), and duration of response (DoR; ML-3 and -7). DoR was an exploratory endpoint in ML-2.

Results: Data were pooled for 820 pts treated with RIB + ET (ML-2: n=334; ML-3: n=238; ML-7: n=248) and 710 pts treated with PBO + ET (ML-2: n=334; ML-3: n=129; ML-7: n=247). As of the data cutoffs (ML-2: January 2, 2017; ML-3: November 3, 2017; ML-7: August 20, 2017), in the RIB + ET vs PBO + ET arms, 385 (47%) vs 234 (33%) pts remained on-treatment; the most common reason for discontinuation was disease progression (n=292 [36%] vs n=391 [55%]). In this pooled analysis, median PFS was prolonged for RIB + ET vs PBO + ET, with a hazard ratio of 0.570 (95% confidence interval [CI] 0.491–0.662); median PFS was 25.3 months (95% CI 23.9–29.6) vs 15.6 months (95% CI 14.4–16.9), respectively. Consistent PFS benefit for RIB + ET vs PBO + ET was observed across pt subgroups, including ECOG performance status, age, race, or presence/absence of liver and/or lung metastases or bone-only disease. Among all pts in the pooled analysis, the ORR was 41% for RIB + ET vs 28% for PBO + ET and the CBR was 79% vs 70%, respectively. In pts with measurable disease at baseline (RIB + ET: n=639; PBO + ET: n=542), the ORR was 51% for RIB + ET vs 37% for PBO + ET and the CBR was 79% vs 68%, respectively. In the RIB + ET vs PBO + ET arms, the median DoR was 26.7 months vs 20.0 months. A decrease in best percentage change from baseline in the sum of longest diameters per RECIST was observed in 86% of pts receiving RIB + ET vs 73% of pts receiving PBO + ET.

Conclusions: RIB in combination with various ET partners demonstrates improved clinical outcomes vs PBO + ET across a broad population of pts with HR+, HER2– ABC. These data provide further support for the use of RIB-based combinations in pre- and postmenopausal pts with HR+, HER2– ABC who have received no prior ET for advanced disease.

Citation Format: Tripathy D, Hortobagyi G, Chan A, Im S-A, Chia S, Yardley D, Esteva FJ, Hurvitz S, Kong O, Bao W, Rodriguez Lorenc K, Diaz-Padilla I, Slamon DJ. First-line ribociclib + endocrine therapy in hormone receptor-positive, HER2-negative advanced breast cancer: A pooled efficacy 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 P6-18-05.

Abstract P1-07-09: Serum activin A and outcomes in HR+ /HER2- metastatic breast cancer patients treated with everolimus: Results from BOLERO-2

Background: Everolimus (EVE) plus exemestane (EXE) doubled progression-free survival (PFS) while maintaining quality of life versus EXE alone in postmenopausal women with hormone receptor positive (HR+), HER2-negative metastatic breast cancer (mBC) (BOLERO-2 phase 3; NCT00863655). Pretreatment serum activin A was previously reported as a prognostic factor in first-line hormone therapy (letrozole vs tamoxifen) (Novartis P025) and anti-HER2 mBC (lapatinib vs trastzmab) (CCTG MA.31) trials. Here we investigate the prognostic and predictive ability of activin A in BOLERO-2.

Methods: Activin A levels were determined on pretreatment serum samples using ELISA. Cox-proportional hazards model was used to assess the efficacy of EVE in the activin A low and high subgroups (median cut-point), and the prognostic effect of activin A on PFS and overall survival (OS).

Results: Baseline activin A levels were determined in 513 patients (71% of 725 BOLERO-2 patients randomized 2:1 to EVE+EXE or EXE). Predictive and prognostic signals are shown in the table below

Predictive and prognostic signalsPredictive/PrognosticEnd-pointAct-ivin ATreatmentNEventsMedian PFSHR (95% CI); p valuepredictivePFSHEXE93832.5 (1.5-2.8)-predictivePFSHEVE+EXE1631325.4 (4.1-6.8)0.46 (0.34 - 0.60); &lt;0.0001predictivePFSLEXE89774.2 (2.0 -5.4)-predictivePFSLEVE+EXE1681059.9 (8.1-12.5)0.38 (0.28 - 0.51); &lt;0.0001predictiveOSHEXE936820.1 (13.8-22.6)-predictiveOSHEVE+EXE16312917.7 (15.7-22.3)1.04 (0.78 - 1.40); 0.78predictiveOSLEXE8939NA (34.7-NA)-predictiveOSLEVE+EXE1687241.4 (36.4-NA)1.02 (0.69 - 1.50); 0.93prognosticPFSH 2562154.1 (2.9-4.2)-prognosticPFSL 2571826.9 (6.7-8.5)0.54 (0.45 - 0.66); &lt;0.0001prognosticOSH 25619718.0 (16.5-21.1)-prognosticOSL 25711142.3 (38.5-NA)0.34 (0.27 - 0.42); &lt;0.0001

.

In multivariate analysis (including sensitivity to prior hormone therapy and visceral disease), activin A remained a significant independent prognostic factor for PFS and OS [HR 0.57 (0.46-0.69) and 0.34 (0.27-0.43), respectively].

Conclusions: Higher serum activin A was strongly associated with shorter PFS and OS in HR+/HER2- mBC patients. Everolimus was efficacious regardless of serum activin A level. These results are similar to our previous studies in phase 3 trials of letrozole-tamoxifen (Novartis P025), and HER2-targeted therapy, lapatinib vs trastuzmab (CCTG MA.31): pretreatment serum activin A was prognostic for outcome, but was not a predictive factor for treatment arm selection.

Citation Format: Ali SM, Chen D, Ali A, Krecko L, Leitzel K, Vasekar M, Nagabhairu V, Marks E, Polimera H, Richardson A, May M, He W, Patel P, Lavin M, Hofsess S, Sweetman R, Hortobagyi G, Baselga J, Lipton A. Serum activin A and outcomes in HR+ /HER2- metastatic breast cancer patients treated with everolimus: Results from BOLERO-2 [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-07-09.

Abstract OT3-05-06: EarLEE-2: A phase 3 study of ribociclib + endocrine therapy (ET) for adjuvant treatment of patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–), intermediate-risk, early breast cancer (EBC)

Background: Adjuvant ET with or without chemotherapy reduces the risk for recurrence of HR+, HER2– EBC. However, recurrence is still common, especially in patients with adverse clinical and pathologic features. In the phase 3 MONALEESA-2 trial, the cyclin-dependent kinase 4/6 inhibitor ribociclib (LEE011), in combination with letrozole, prolonged progression-free survival versus letrozole plus placebo in postmenopausal women with HR+, HER2– advanced breast cancer and no prior therapy for advanced disease (HR = 0.56, 95% CI, 0.43-0.72; P = 3.29×10−6; Hortobagyi et al. N Engl J Med. 2016). EarLEE-2 is investigating the efficacy and safety of ribociclib with ET versus placebo with ET as adjuvant treatment in patients with intermediate-risk EBC.

Trial design: In this double-blind, placebo-controlled, phase 3 adjuvant trial, ˜4,000 women and men with fully resected, intermediate-risk, HR+, HER2– EBC (defined as AJCC 8th ed. Prognostic Stage Group II) are being randomized 1:1 to oral ribociclib (600 mg/day, 3 weeks on/1 week off for ˜24 months) plus ET or to placebo plus ET. Adjuvant ET may include tamoxifen, letrozole, anastrozole, or exemestane for ≥ 60 months with ovarian suppression for premenopausal women at the discretion of the investigator. Adjuvant ET in men will be tamoxifen only. Neoadjuvant therapy is not permitted. Randomization is stratified by menopausal status (men and premenopausal women vs postmenopausal women), prior adjuvant chemotherapy (yes vs no), Prognostic Stage Group (IIA vs IIB), and geographic region (North America/Europe/Australia vs rest of the world). Eligible patients must have tumor tissue from the surgical specimen, adequate bone marrow and organ functions, normal serum electrolytes, QTc interval &lt; 450 msec, and completed and recovered from acute toxicities of adjuvant radiotherapy and/or chemotherapy. The primary endpoint is invasive disease-free survival (per STEEP system; Hudis et al. J Clin Oncol. 2007). Secondary endpoints include recurrence-free survival, distant disease-free survival, overall survival, quality of life, and safety. Global recruitment to EarLEE-2 is ongoing. NCT03081234

Citation Format: O'Shaughnessy J, Alba E, Bardia A, Dent S, Dieras V, Hortobagyi G, Im S-A, Montemurro F, Untch M, Yardley DA, Chakravartty A, Germa C, Miller M, Slamon D. EarLEE-2: A phase 3 study of ribociclib + endocrine therapy (ET) for adjuvant treatment of patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–), intermediate-risk, early breast cancer (EBC) [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 OT3-05-06.

Abstract P3-08-04: Withdrawn

This abstract was withdrawn by the authors.

Abstract P1-13-12: Quality of life and patient-reported outcomes in US patients enrolled in the MONALEESA-2 study

Background: Improvement to and maintenance of the highest possible health-related quality of life (QoL), in addition to disease control, are key goals of treatment in patients with advanced breast cancer (ABC). Endocrine therapy is preferred as first-line therapy in ABC because of its preferable safety profile compared with chemotherapy. In the MONALEESA-2 study, the cyclin-dependent kinases 4 and 6 inhibitor ribociclib, in combination with letrozole, significantly extended progression-free survival (PFS) compared with placebo + letrozole in patients with hormone receptor–positive (HR+), human epidermal growth factor receptor 2–negative (HER2−) ABC. Patient-reported outcomes demonstrated similar QoL among patients in both treatment groups. Here, we present data from US patients enrolled in the MONALEESA-2 study on overall QoL as well as individual domains.

Methods: Postmenopausal women (N=668) with HR+, HER2− ABC who did not receive prior systemic treatment for ABC and had an Eastern Cooperative Oncology Group performance status score of ≤1, adequate bone marrow and organ function, and no history of active cardiac dysfunction were randomized 1:1 to receive either ribociclib (600 mg/d, 3 weeks on/1 week off) + letrozole (2.5 mg/d, continuous) or placebo + letrozole. The primary end point was locally assessed PFS. Quality of life was reported using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30), the EuroQol 5-domain 5 level (EQ-5D-5L) visual analog scale (VAS) of overall health, and the breast symptom score of the EORTC QLQ-Breast Cancer 23 (EORTC QLQ-BR23) module. Data cutoff in this analysis was January 29, 2016.

Results: Patient characteristics and QoL survey reports were well balanced across treatment groups in US patients (n=213). The global health status/QoL scores of the EORTC QLQ-C30 were maintained between groups, and improved over time in the ribociclib group (mean ± standard deviation [SD] score at baseline, 69.1 ± 19.0; at 8 months, 71.3 ± 18.2; and at 16 months, 73.0 ± 16.0) and the placebo group (mean ± SD score at baseline, 69.9 ± 20.0; at 8 months, 75.9 ± 19.2; and at 16 months, 77.0 ± 15.0), which was consistent with scores in the overall population. At 16 months, the proportion of patients who did not experience ≥10% deterioration of all QoL scores was similar among treatment groups.

Quality of Life Outcomes of US Patients in the MONALEESA-2 Study at 16 MonthsOutcomeTreatment, nPatients without ≥10% deterioration in score, % (95% CI, %)EORTC QLQ-C30  Global health status/QoLRIB + LET, 2664.0 (49.4–75.4) PBO + LET, 3550.5 (36.2–63.2)Physical functioningRIB + LET, 2175.7 (62.6–84.7) PBO + LET, 1773.1 (57.2–83.9)Emotional functioningRIB + LET, 2271.6 (58.6–81.2) PBO + LET, 3159.7 (45.7–71.2)Social functioningRIB + LET, 1780.1 (68.5–87.8) PBO + LET, 2660.2 (44.1–73.0)EORTC QLQ-BR23 breast symptom scoreRIB + LET, 888.0 (76.6–94.0) PBO + LET, 886.2 (70.6–93.9)EQ-5D-5L VAS of overall healthRIB + LET, 1386.6 (76.9–92.4) PBO + LET, 1873.4 (56.8–84.4)LET, letrozole; PBO, placebo; RIB, ribociclib.

Conclusions: Addition of ribociclib to letrozole in US patients enrolled in MONALEESA-2 led to significant prolongation of PFS while maintaining QoL.

Citation Format: Tolaney SM, Tan-Chiu E, Truica C, Volas-Redd G, Shtivelband M, Dalal AA, Chandiwana D, Hortobagyi G. Quality of life and patient-reported outcomes in US patients enrolled in the MONALEESA-2 study [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 P1-13-12.

Abstract 4970: Oxidative phosphorylation as a target in triple negative breast cancer therapy

Altered cellular metabolism is a hallmark of cancer. It is increasingly recognized that selected tumors are dependent on oxidative phosphorylation (OXPHOS). However, the role of OXPHOS in TNBC is not well understood. We performed RNA sequencing in pre-treatment biopsies from 43 patients with operable triple negative breast cancer (TNBC) who received sequential taxane- and anthracycline-based neoadjuvant chemotherapy. At a median follow-up of 63 months, 14 patients recurred and 12 patients died. At a false discovery rate of 0.05, 33 genes were differentially expressed between the patients who did and did not have a subsequent recurrence. Ingenuity pathway analysis demonstrated that one of the top canonical pathways that differed was higher expression of oxidative phosphorylation signature (p=5.89E-0.7). The patients who recurred had significantly higher levels of mitochondrial genes: MT-ND1 (adjusted p or FDR-BH; q=0.007); MT-ND5 (q=0.03) and MT-ND4 (q=0.04). Further, 21 genes were differentially expressed between patients based on survival, including MT-ND5 (q=0.001); MT-ND4 (q=0.005), MT-ND4L (q=0.015), MT-ND6 (q=0.018), and MT-ATP6 (P=0.03). Top canonical pathway that was differentially expressed based on survival was oxidative phosphorylation (p=9.98E-10). We therefore sought to determine the efficacy of IACS-10759, a novel inhibitor of OXPHOS, in 10 different TNBC patient-derived xenografts representing different gene expression based Lehmann TNBC subtypes. Growth inhibition was observed in multiple subtypes, with regression in one basal-like 1(BL1) 1 model, and stabilization of growth in multiple BL1 and immunomodulatory expression subtypes. Taken together, our data suggests that high OXPHOS is associated with higher recurrence and lower survival. OXPHOS is a promising target in several TNBC subtypes. A Phase I trial of IACS-10759, a potent inhibitor of complex I of oxidative phosphorylation, in leukemia is ongoing and planned in TNBC and other solid tumors.

Citation Format: Funda Meric-Bernstam, Kurt Evans, Xiaofeng Zheng, Xiaoping Su, Erkan Yuca, Stephen Scott, Argun Akcakanat, Naoto Ueno, Bora Lim, Jennifer Litton, Vicente Valero, Fraser Symmans, Gabriel Hortobagyi, Charles Perou, Debu Tripathy, Guilio Draetta, Joe Marszalek, Ana Maria Gonzalez-Angulo, Stacy Moulder. Oxidative phosphorylation as a target in triple negative breast cancer therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4970. doi:10.1158/1538-7445.AM2017-4970

Prevalence of ESR1 Mutations in Cell-Free DNA and Outcomes in Metastatic Breast Cancer: A Secondary Analysis of the BOLERO-2 Clinical Trial

Importance

Estrogen receptor α (ESR1) mutations found in metastatic breast cancer (MBC) promote ligand-independent receptor activation and resistance to estrogen-deprivation therapy in laboratory models. The prevalence of these mutations and their potential impact on clinical outcomes has not been established.

Objective

To determine the prevalence of ESR1 mutations (Y537S and D538G) in estrogen receptor (ER)-positive MBC and determine whether mutation is associated with inferior outcomes.

Design, Setting, and Participants

From December 16, 2014, to August 26, 2015, we analyzed cell-free DNA (cfDNA) from baseline plasma samples from participants in the BOLERO-2 double-blind phase 3 study that randomized patients from 189 centers in 24 countries with MBC to exemestane plus placebo or exemestane plus everolimus. The study enrolled postmenopausal women with a diagnosis of MBC and prior exposure to an aromatase inhibitor. Baseline plasma samples were available from 541 of 724 patients (74.7%). We assessed the effect of mutation on overall survival of the population and the effect of mutation on progression-free survival (PFS) by treatment arm.

Interventions

Patients were randomized to treatment with exemestane (25 mg oral daily) together with everolimus (10 mg oral daily) or with placebo.

Main Outcomes and Measures

The 2 most frequent mutations in ESR1 (Y537S and D538G) were analyzed from cfDNA using droplet digital polymerase chain reaction and samples scored as wild-type, D538G, Y537S, or double mutant. Cox-proportional hazards model was used to assess PFS in patient subgroups defined by mutations, and the effect of each mutation on overall survival.

Results

Of 541 evaluable patients, 156 (28.8%) had ESR1 mutation D538G (21.1%) and/or Y537S (13.3%), and 30 had both. These mutations were associated with shorter overall survival (wild-type, 32.1 months [95% CI, 28.09-36.40 months]; D538G, 25.99 months [95% CI, 19.19-32.36 months]; Y537S, 19.98 months [13.01-29.31 months]; both mutations, 15.15 months [95% CI, 10.87-27.43 months]). The D538G group (hazard ratio, 0.34 [95% CI, 0.02-0.57]) derived a similar PFS benefit as wild type from addition of everolimus to exemestane.

Conclusions and Relevance

ESR1 mutations are prevalent in ER-positive aromatase inhibitor-treated MBC. Both Y537S and D538G mutations are associated with more aggressive disease biology.

Trial Registration

clinicaltrials.gov Identifier: NCT00863655.

Acute and Short-term Toxic Effects of Conventionally Fractionated vs Hypofractionated Whole-Breast Irradiation: A Randomized Clinical Trial

IMPORTANCE

The most appropriate dose fractionation for whole-breast irradiation (WBI) remains uncertain.

OBJECTIVE

To assess acute and 6-month toxic effects and quality of life (QOL) with conventionally fractionated WBI (CF-WBI) vs hypofractionated WBI (HF-WBI).

DESIGN, SETTING, AND PARTICIPANTS

Unblinded randomized trial of CF-WBI (n = 149; 50.00 Gy/25 fractions + boost [10.00-14.00 Gy/5-7 fractions]) vs HF-WBI (n = 138; 42.56 Gy/16 fractions + boost [10.00-12.50 Gy/4-5 fractions]) following breast-conserving surgery administered in community-based and academic cancer centers to 287 women 40 years or older with stage 0 to II breast cancer for whom WBI without addition of a third field was recommended; 76% of study participants (n = 217) were overweight or obese. Patients were enrolled from February 2011 through February 2014 and observed for a minimum of 6 months.

INTERVENTIONS

Administration of CF-WBI or HF-WBI.

MAIN OUTCOMES AND MEASURES

Physician-reported acute and 6-month toxic effects using National Cancer Institute Common Toxicity Criteria, and patient-reported QOL using the Functional Assessment of Cancer Therapy for Patients with Breast Cancer (FACT-B). All analyses were intention to treat, with outcomes compared using the χ2 test, Cochran-Armitage test, and ordinal logistic regression.

RESULTS

Of 287 participants, 149 were randomized to CF-WBI and 138 to HF-WBI. Treatment arms were well matched for baseline characteristics, including FACT-B total score (HF-WBI, 120.1 vs CF-WBI, 118.8; P = .46) and individual QOL items such as somewhat or more lack of energy (HF-WBI, 38% vs CF-WBI, 39%; P = .86) and somewhat or more trouble meeting family needs (HF-WBI, 10% vs CF-WBI, 14%; P = .54). Maximum physician-reported acute dermatitis (36% vs 69%; P < .001), pruritus (54% vs 81%; P < .001), breast pain (55% vs 74%; P = .001), hyperpigmentation (9% vs 20%; P = .002), and fatigue (9% vs 17%; P = .02) during irradiation were lower in patients randomized to HF-WBI. The rate of overall grade 2 or higher acute toxic effects was less with HF-WBI than with CF-WBI (47% vs 78%; P < .001). Six months after irradiation, physicians reported less fatigue in patients randomized to HF-WBI (0% vs 6%; P = .01), and patients randomized to HF-WBI reported less lack of energy (23% vs 39%; P < .001) and less trouble meeting family needs (3% vs 9%; P = .01). Multivariable regression confirmed the superiority of HF-WBI in terms of patient-reported lack of energy (odds ratio [OR], 0.39; 95% CI, 0.24-0.63) and trouble meeting family needs (OR, 0.34; 95% CI, 0.16-0.75).

CONCLUSIONS AND RELEVANCE

Treatment with HF-WBI appears to yield lower rates of acute toxic effects than CF-WBI as well as less fatigue and less trouble meeting family needs 6 months after completing radiation therapy. These findings should be communicated to patients as part of shared decision making.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01266642.

Abstract P1-06-03: Epithelial to mesenchymal transition (EMT) regulates the spontaneous generation of GD2+ breast cancer stem-like cells through NFκB activation

Breast cancer recurrence may be a consequence of persistent breast cancer stem-like cells (BCSCs) that survive chemo- or hormonal therapy. Therefore, targeting BCSCs could complement standard chemotherapy. We discovered that the ganglioside GD2 is expressed on and defines BCSCs (Battula et al., JCI, 2012), as consequence of activation of the enzyme GD3 synthase (GD3S). Inhibition of GD3S expression inhibited breast cancer metastasis to lung. We also observed that GD2- breast cancer cells spontaneously generate GD2+ cells in vitro. As induction of EMT generates a stem cell–like phenotype, we hypothesized that EMT regulates the generation of GD2+ breast cancer cells. To test this hypothesis, MDA-MB-231and SUM159 cells were cultured in vitro and the percentage of GD2+ cells was measured over time. Interestingly, the percentage and absolute number of GD2+ cells increased in a time-dependent manner, suggesting the spontaneous generation of GD2+ cells. Concomitantly, mesenchymal-related markers including vimentin, N-cadherin, and twist increased 3 to 6 - fold. To further investigate whether this process is operational in vivo, GFP+ MDA-MB-231 cells were transplanted into mammary fat pads of NOD/SCID mice. Each week, a group of mice was sacrificed, tumors were extracted and the number of GFP+GD2+ cells was determined by flow cytometry. In line with our in vitro results, we observed significant increases in GD2+ BCSCs with increasing tumor volume from 15.1%±4.6% to 37%±8.7% over a 6 week period, suggesting that breast cancer cells spontaneously undergo EMT during tumor progression and generate GD2+ BCSCs.

To identify possible targets to inhibit EMT in breast cancer cells, proteomic analysis using Kinexus® antibody arrays revealed activation of NFκB and focal adhesion kinase (FAK) signaling in GD2+ breast cancer cells. The activation of NFκB (phospho p65) in GD2+ cells was validated by CyTOF mass cytometry using metal tagged antibodies. These data suggest that inhibition of NFκB signaling may inhibit GD2+ BCSC growth. Indeed, the IKK inhibitor BMS345541 reduced GD2+ cells by &gt;95% and inhibited GD3S expression (determined by qRT-PCR) in a dose- and time-dependent fashion. In contrast, treatment with doxorubicin increased the percentage of GD2+ cells, from 13.5±2.5% to 21±2.6% in MDA-MB-231 cells, suggesting that GD2+ cells are resistant to doxorubicin. In addition, treatment with BMS345541 inhibited the ability of breast cancer cells to form mammospheres by &gt;90% in vitro. In-vivo tumorigenesis assay demonstrated that BMS345541 induced a significant decrease (p &lt;0.01) in tumor volume, and increased survival of tumor bearing mice: median survival was 78 days for BMS345541-treated mice vs. 58 days for controls (p&lt;0.002).

Conclusion: GD2+ BCSCs are spontaneously produced during tumor progression by EMT and NFκB and FAK mediated signaling might regulate this process. Inhibition of NFκB and FAK signaling pathways may inhibit the spread of BCSCs and reduce breast cancer metastases.

Citation Format: Battula VL, Sun J, Nguyen K, Hortobagyi G, Andreeff M. Epithelial to mesenchymal transition (EMT) regulates the spontaneous generation of GD2+ breast cancer stem-like cells through NFκB activation. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-06-03.

Incidence and time course of everolimus-related adverse events in postmenopausal women with hormone receptor-positive advanced breast cancer: insights from BOLERO-2

BACKGROUND

In the BOLERO-2 trial, everolimus (EVE), an inhibitor of mammalian target of rapamycin, demonstrated significant clinical benefit with an acceptable safety profile when administered with exemestane (EXE) in postmenopausal women with hormone receptor-positive (HR(+)) advanced breast cancer. We report on the incidence, time course, severity, and resolution of treatment-emergent adverse events (AEs) as well as incidence of dose modifications during the extended follow-up of this study.

PATIENTS AND METHODS

Patients were randomized (2:1) to receive EVE 10 mg/day or placebo (PBO), with open-label EXE 25 mg/day (n = 724). The primary end point was progression-free survival. Secondary end points included overall survival, objective response rate, and safety. Safety evaluations included recording of AEs, laboratory values, dose interruptions/adjustments, and study drug discontinuations.

RESULTS

The safety population comprised 720 patients (EVE + EXE, 482; PBO + EXE, 238). The median follow-up was 18 months. Class-effect toxicities, including stomatitis, pneumonitis, and hyperglycemia, were generally of mild or moderate severity and occurred relatively early after treatment initiation (except pneumonitis); incidence tapered off thereafter. EVE dose reduction and interruption (360 and 705 events, respectively) required for AE management were independent of patient age. The median duration of dose interruption was 7 days. Discontinuation of both study drugs because of AEs was higher with EVE + EXE (9%) versus PBO + EXE (3%).

CONCLUSIONS

Most EVE-associated AEs occur soon after initiation of therapy, are typically of mild or moderate severity, and are generally manageable with dose reduction and interruption. Discontinuation due to toxicity was uncommon. Understanding the time course of class-effect AEs will help inform preventive and monitoring strategies as well as patient education.

TRIAL REGISTRATION NUMBER

NCT00863655.

Abstract P2-16-17: Characterization of response to everolimus (EVE) in BOLERO-2: A phase 3 trial of EVE plus exemestane (EXE) in postmenopausal women with HR+, HER2- advanced breast cancer

Introduction: The BOLERO-2 trial demonstrated that combining the oral mammalian target of rapamycin (mTOR) inhibitor, EVE, with the steroidal aromatase inhibitor, EXE, more than doubled median progression-free survival (PFS) compared with placebo (PBO) plus EXE in postmenopausal women with hormone-receptor-positive (HR+), human epidermal growth factor receptor-2-negative (HER2−) breast cancer (BC) who relapsed or progressed following a nonsteroidal aromatase inhibitor (NSAI). Patients also achieved responses per Response Evaluation Criteria in Solid Tumors (RECIST) during treatment with EVE+EXE.

Methods: The phase 3, double-blind, BOLERO-2 trial randomized postmenopausal women with HR+ BC progressing or recurring after NSAIs in a 2:1 manner to EVE 10 mg once daily plus EXE 25 mg once daily (EVE+EXE; n = 485) or placebo (PBO) plus EXE (PBO+EXE; n = 239). The primary endpoint was PFS by local assessment. Overall response rate (ORR; complete + partial response per investigator assessment based on RECIST 1.0) and duration of overall response were secondary endpoints. In addition, best percentage change from baseline in sum of longest diameters of target lesions was assessed.

Results: At the time of final PFS analyses at 18 months’ median follow-up, ORR was significantly higher in the EVE+EXE arm compared with the PBO+EXE arm (12.6% vs 1.7%, respectively, by local assessment; P&lt;.0001). Among patients with measurable disease at baseline, 71% in the EVE+EXE arm had a decrease in the sum of longest diameters of target lesions compared with baseline vs 30% in the PBO+EXE arm. Median duration of overall response was 10.5 months (95% confidence interval [CI]: 8.2, 21.9 months) for EVE+EXE and 6.9 months (95% CI: 4.2, 6.9 months) for PBO+EXE. Of note, only 4 patients in the PBO+EXE arm had an objective response to treatment.

Conclusions: In addition to PFS, the combination of EVE plus EXE significantly improved ORR vs PBO+EXE in patients with HR+, HER2− advanced BC progressing during or after NSAI therapy. Furthermore, greater than two-thirds of patients treated with EVE+EXE experienced tumor shrinkage during treatment. These results further support the rationale for combining EVE with EXE to improve clinical outcomes in HR+, HER2− advanced BC progressing after NSAI therapy.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-17.

Ganglioside GD2 identifies breast cancer stem cells and promotes tumorigenesis

Cancer stem cells (CSCs) are a small subpopulation of cancer cells that have increased resistance to conventional therapies and are capable of establishing metastasis. However, only a few biomarkers of CSCs have been identified. Here, we report that ganglioside GD2 (a glycosphingolipid) identifies a small fraction of cells in human breast cancer cell lines and patient samples that are capable of forming mammospheres and initiating tumors with as few as 10 GD2+ cells. In addition, the majority of GD2+ cells are also CD44hiCD24lo, the previously established CSC-associated cell surface phenotype. Gene expression analysis revealed that GD3 synthase (GD3S) is highly expressed in GD2+ as well as in CD44hiCD24lo cells and that interference with GD3S expression, either by shRNA or using a pharmacological inhibitor, reduced the CSC population and CSC-associated properties. GD3S knockdown completely abrogated tumor formation in vivo. Also, induction of epithelial-mesenchymal transition (EMT) in transformed human mammary epithelial cells (HMLER cells) dramatically increased GD2 as well as GD3S expression in these cells, suggesting a role of EMT in the origin of GD2+ breast CSCs. In summary, we identified GD2 as a new CSC-specific cell surface marker and GD3S as a potential therapeutic target for CSCs, with the possibility of improving survival and cure rates in patients with breast cancer.

Abstract 682: Increased stearoyl-CoA desaturase 1 expression is associated with shorter survival in breast cancer patients

Stearoyl-CoA desaturase 1 (SCD1) is an essential regulator of fatty acid synthesis that affects cell membrane composition and may play a role in cancer cell metabolism. We have previously shown that SCD1 expression is increased by mTOR signaling and that SCD1 increases breast cancer cell growth in vitro. The purpose of this study was to determine protein levels of SCD1 in breast cancer and to determine whether there is an association between SCD1 levels and survival. Fine needle aspirates were collected from the primary breast cancers of 253 patients with Stage I-III breast cancer and protein lysates were prepared. SCD1 expression was analyzed using reverse phase proteomic array. Patient demographic and clinical characteristics including age, ethnicity, menopausal status, clinical stage, tumor grade, and tumor subtype were reviewed. Samples were divided into high or low SCD1 levels based on a cut-off determined from martingale residual plots and regression tree analysis. SCD1 levels were significantly higher in older patients and lower in triple negative (estrogen, progesterone, and HER2 negative) cancers, After adjusting for tumor subtype, tumor grade, age, and clinical stage, patients who had high SCD1 levels had significantly shorter relapse-free survival (RFS) (p=0.013) and overall survival (OS) (p=0.038). SCD1 level varies by breast cancer subtype and predicts significantly shorter RFS and OS. Future studies are needed to define the role of SCD1 in breast cancer and evaluate its potential as a therapeutic target.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 682. doi:1538-7445.AM2012-682

Abstract CT-03: Aberrations in translational regulation are associated with poor prognosis in hormone receptor-positive breast cancer

Purpose: Translation initiation is activated in cancer through increase in eukaryotic initiation factor 4E (eIF4E), eIF4G, phosphorylated eIF4E-binding protein (p4E-BP1) and ribosomal protein S6 (pS6), and decreased programmed cell death protein 4 (pdcd4), a translational inhibitor. Further, translation elongation is deregulated though alterations in eukaryotic elongation factor 2 (eEF2) and eEF2 kinase (eEF2K). We sought to determine the association of these translational aberrations with clinical-pathologic factors and survival outcomes in hormone receptor-positive breast cancer. Methods: Primary tumors were collected from 190 patients with stage I-III hormone receptor-positive breast cancer. Expression of eIF4E, eIF4G, 4E-BP1, p4E-BP1 T37/46, p4E-BP1 S65, p4E-BP1 T70, S6, pS6 S235/236, pS6 S240/244, pdcd4, eEF2 and eEF2K was assessed by reverse phase protein arrays.: Univariable and multivariable analyses for recurrence-free survival (RFS) and overall survival (OS) were performed. Results: High eEF2, S6, pS6 S240/244, p4E-BP1 T70, and low pdcd4 were significantly associated with node-positivity. Median follow-up for alive patients was 96 months. High p4E-BP1 T36/47, p4E-BP1 S65, p4E-BP1 T70 and 4E-BP1 were associated with worse RFS. High p4E-BP1 T70 and pS6 S235/236, and low pdcd4, were associated with worse OS. In multivariable analysis, in addition to positive nodes, p4E-BP1 S65 remained a significant predictor of RFS (HR=1.62, 95%CI=1.13-2.31; P=0.008). In addition to age, pS6 S235/236 (HR=1.73, 95%CI=1.03-2.90, P=0.039), eEF2K (HR=2.19, 95%CI=1.35-3.56, P=0.002) and pdcd4 (HR=0.42, 95%CI=0.25-0.70, P=0.001) were associated with OS. Conclusions: Increased pS6, p4E-BP1, eEF2K and decreased pdcd4 are associated with poor prognosis in hormone receptor-positive breast cancer; suggesting their role as prognostic markers and therapeutic targets.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr CT-03. doi:1538-7445.AM2012-CT-03

Abstract LB-379: Combating trastuzumab resistance by targeting Src, a common node downstream of multiple resistance pathways

Objective of the study: Trastuzumab is a highly successful example of rationally designed ERBB2-targeted therapy. However, about half of patients with ERBB2-overexpressing breast cancer do not respond to trastuzumab-based therapies due to various resistance mechanisms. Clinically applicable regimens for overcoming trastuzumab resistance of different mechanisms are not yet available. The objective of the study is to find a common key node of multiple trastuzumab resistance mechanisms and design a clinical applicable strategy to target this common node to more effectively overcome trastuzumab resistance. Methodology: First, we evaluated Src activity in multiple acquired and de novo trastuzumab-resistant cell lines models. Cells with modulated Src activity were examined for trastuzumab resistance in vitro and in an orthotopic xenograft model. Moreover, tumors from patients receiving trastuzumab therapy were also analyzed retrospectively for clinical correlation of Src activity with trastuzumab response. Src activated trastuzumab-resistant cells were further treated with Src inhibitor (saracatinib), trastuzumab, or a combination of both in vitro and in vivo. Results: We demonstrate that the non-receptor tyrosine kinase Src serves as a critical modulator of trastuzumab response and a common node downstream of multiple trastuzumab resistance pathways. Src is activated in both acquired and de novo trastuzumab-resistant cells. Increased Src activation conferred significant trastuzumab resistance (P = 0.011) in breast cancer cells and correlated with trastuzumab resistance in patients. Targeting the common node Src in combination with trastuzumab universally sensitized multiple lines of trastuzumab-resistant cells to trastuzumab and eliminated trastuzumab-resistant tumors in vivo. Targeting Src, a critical convergence point of divergent trastuzumab resistance mechanisms, represents a highly effective and clinically convenient strategy to overcome trastuzumab resistance.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-379. doi:10.1158/1538-7445.AM2011-LB-379

Multidisciplinary meeting on male breast cancer: summary and research recommendations

Male breast cancer is a rare disease, accounting for less than 1% of all breast cancer diagnoses worldwide. Most data on male breast cancer comes from small single-institution studies, and because of the paucity of data, the optimal treatment for male breast cancer is not known. This article summarizes a multidisciplinary international meeting on male breast cancer, sponsored by the National Institutes of Health Office of Rare Diseases and the National Cancer Institute Divisions of Cancer Epidemiology and Genetics and Cancer Treatment and Diagnosis. The meeting included representatives from the fields of epidemiology, genetics, pathology and molecular biology, health services research, and clinical oncology and the advocacy community, with a comprehensive review of the data. Presentations focused on highlighting differences and similarities between breast cancer in males and females. To enhance our understanding of male breast cancer, international consortia are necessary. Therefore, the Breast International Group and North American Breast Cancer Group have joined efforts to develop an International Male Breast Cancer Program and to pool epidemiologic data, clinical information, and tumor specimens. This international collaboration will also facilitate the future planning of clinical trials that can address essential questions in the treatment of male breast cancer.

Quantitative immunohistochemical analysis and prognostic significance of TRPS-1, a new GATA transcription factor family member, in breast cancer

The trichorhinophalangeal syndrome 1 (TRPS-1) gene is a novel GATA transcription factor family member. Previously, using a gene expression profiling and immunohistochemistry (IHC) screen, we identified TRPS-1 as a highly prevalent gene in breast cancer (BC), expressed in >90% of estrogen receptor alpha (ERα)(+) and ERα(-) BC subtypes. TRPS-1 was also shown to be expressed in prostate cancer where it was shown to play a proapoptotic function during androgen withdrawal possibly through regulating antioxidant metabolism. The role of TRPS-1 and its prognostic significance in hormone-dependent and hormone-independent BC however is not known. In this study, we developed a new quantitative IHC (qIHC) method to further study TRPS-1 as a marker and possible prognostic indicator in BC. By using this method, a quantitative parameter for TRPS-1 expression called a quick score (QS) was derived from the measured labeling index and mean optical density after IHC and applied to a set of 152 stage II/III BC patients from 1993 to 2006 who did not receive preoperative chemotherapy. Associations between QS and tumor characteristics were evaluated using the Kruskal-Wallis test. A wide range of TRPS-1 QS was found among the sample set with higher TRPS-1 QS significantly associated with tumor ERα (p = 0.023 for QS and p = 0.028 for Allred score), progesterone receptor (p = 0.009), and GATA-3 (p < 0.0001). TRPS-1 QS was also positively associated with HER2 status (p = 0.026). Further analysis of different ductal structures in ten BC cases revealed that TRPS-1 expression was expressed at low levels in the remaining normal ducts and in areas of usual ductal hyperplasia but showed marked increase in expression in ductal carcinoma in situ and invasive carcinoma lesions in the tissue. An analysis of TRPS-1 expression in association with overall survival in the 152 stage II/III sample set also revealed that TRPS-1 QS (≥4.0) was significantly associated with improved survival (p = 0.0165). Patients with TRPS-1 QS <4 had a hazard ratio of 2 (p = 0.019) after univariate Cox proportional hazards analysis. In summary, this new qIHC approach was found to reveal critical differences in TRPS-1 expression in primary BC samples and found that it is a promising prognostic marker that should be further evaluated as a possible tumor suppressor gene facilitating improved survival in different subtypes of BC.

Different Biological Processes Are Associated with Prognosis and Chemotherapy Sensitivity in the Different Molecular Subtypes of Breast Cancer

Background: Breast cancer includes multiple different molecular subtypes. We hypothesized that different biological processes and molecular markers may be associated with prognosis and chemotherapy sensitivity in the different subtypes.Methods: We performed gene set analysis in ER-positive/HER-2-normal (ER+) and ER-negative/HER-2-normal (ER-) cancers separately to identify gene sets that are associated with prognosis and chemotherapy sensitivity. We tested 5295 different, functionally annotated gene sets (GS) that collectively represent almost all known biological and metabolic pathways in human cells. Significance was estimated with permutation test. Three separate cohorts on untreated HER2-normal patients (n=234, n=175, n=170) and 3 cohorts of patients with neoadjuvant therapy (n=198, n=85, n=61) were included in this analysis. We performed analysis of each data set separately and also as pooled data.Results: When data sets were analyzed individually, 753 to 938 GS were associated with prognosis (P≤0.05) in ER+ cancers including 186 common to all, and 408 to 579 GS were associated with prognosis in ER- cancers including 1 common to all and 141 common to at least two data sets. Within each data set, the number of overlapping GS between the ER+ and ER- prognostic lists ranged from 33 to 112. In the neoadjuvant data sets, 555 to 674 GS were associated with response in ER+ cancers (195 common to at least two, 4 common to all) and 543 to 730 in ER- cancers (268 common to two, 22 common to all). When the predictive GS for ER+ cancers were compared to those for ER- cancers, there were only 10 GS in common. A meta analyses of the combined prognostic data sets yielded 384 GS with p≤0.0001 in ER+ cancers and 47 in ER- cancers, respectively, with 12 GS common to both. A meta analyses of the combined neoadjuvant data sets yielded 92 GS associated with pCR in ER+ cancers and 110 GS in the ER- cancers. Only 2 GS were common to both. Functional analysis indicated that DNA replication, mitotic spindle checkpoint and plasma cell function were the most common prognostic pathways in ER+ cancer. T cell differentiation, glycolipid metabolism and immune functions were the most commonly prognostic pathways in ER- cancer with a notable absence of proliferation related gene sets. DNA replication, spindle and microtubule activity and cell cycle regulation were associated with chemotherapy response in ER+ cancers; oxidative stress, blood vessel formation in ER- cancers.Conclusion: These data indicate that prognosis and chemotherapy response are associated with different gene sets in ER+ and ER- cancers.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6124.

Addition of Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) to Trastuzumab Stabilizes Disease in Patients with Trastuzumab-Resistant, HER2+ Metastatic Breast Cancer

Introduction: Trastuzumab with or without chemotherapy is the standard of care for patients with HER2+ metastatic breast cancer. The proposed mechanism of trastuzumab-induced regression of HER2+ tumors includes inhibition of tumor cell proliferation, potentiation of chemotherapy, and facilitation of immune function through antibody-dependent cell-mediated cytotoxicity. GM-CSF (Leukine) is a cytokine that mediates antibody-dependent cell-mediated cytotoxicity. We studied the feasibility and efficacy of adding GM-CSF to trastuzumab in patients with trastuzumab-resistant, HER2+ metastatic breast cancer.Patients and Methods: Patients with measurable, HER2+ metastatic breast cancer that progressed after treatment with trastuzumab with or without chemotherapy were continued on trastuzumab alone at 2 mg/kg intravenous weekly. GM-CSF (250 μg/m2 subcutaneous daily) was added until the absolute neutrophil count (ANC) was greater than 10,000/mm3, then given every other day while the ANC was maintained below 10,000/mm3. Disease was restaged every 8 weeks. Treatment with trastuzumab and GM-CSF was continued until disease progression or intolerable toxicity.Results: Of 18 eligible patients with progressive HER2+ metastatic breast cancer, 17 (median age 48 yr, range 27–75 yr) were evaluable. Nine had hormone receptor–positive disease. The median number of metastatic sites was 2 (range 1–3); the most common site was the liver (n=10). The median number of prior regimens (trastuzumab with or without chemotherapy) for metastatic disease was 2 (range 1–5). One patient developed rapidly progressive disease 2 weeks after the start of study therapy and died soon after. The other 16 patients continued treatment until disease progression. No disease response was observed, but 5 patients (29%) had stable disease with a median duration of 15.8 weeks (range 10–53.9 weeks). Thirteen patients had grade 1 toxic effects; 6 patients, grade 2; and 2 patients, grade 3 (fatigue and muscle aches). The most common toxic effect was rash at the injection site, followed by skin rash, fatigue, and muscle aches. No grade 4 or irreversible toxic effect was seen.Conclusion: The addition of GM-CSF to trastuzumab alone in patients with trastuzumab-resistant, HER2+ metastatic breast cancer stabilizes the disease for a median duration of 15.8 weeks without causing any significant toxic effects in 29% of heavily pretreated patients. Its administration is simple, safe, and feasible. This regimen, trastuzumab and GM-CSF, needs further evaluation in combination with chemotherapy or other biological agents.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5103.

Variants in the BRCA1/Fanconi-Anemia Repair Pathway and Taxane-Induced Neuropathy in SWOG S0221

Background: Taxane-induced peripheral neuropathy is a dose-limiting side effect that leads to suboptimal cancer treatment and diminished quality of life. The mode of taxane neurotoxicity is unclear, but may be through stabilization of microtubules and induction of spindle checkpoint, leading to cell cycle arrest at G2/M. Fanconi Anemia (FA) genes, including FANCD2, and FANCA, appear to be involved in G2/M phase checkpoint maintenance as well as spindle checkpoint in response to internal and external signals, such as taxane treatment. Thus, we hypothesized that variants in FA genes could impact severity of taxane-induced neuropathies.Methods: Using DNA extracted from blood collected from 893 breast cancer patients participating in a trial evaluating metronomic dosing of cyclophosphamide, doxorubicin and paclitaxel (S0221), we genotyped for single nucleotide polymorphisms (SNPs) that represent all of the variability across FANCA (44 SNPs) and FANCD2 (24 SNPs) in all race/ethnicity groups, as well as a panel of ancestry informative markers to control for potential population stratification, using Illumina GoldenGate platform. SNPs with minor allele frequency (MAF) less than 0.10 and those out of Hardy Weinberg Equilibrium (HWE) proportions (p&lt;0.001) were removed from analyses. Ordinal regression was used to test for allelic and haplotypic association with grade 3 or 4 toxicities relative to 0, 1, and 2 toxicities, adjusting for age, genetic admixture index and treatment arm. To adjust for multiple testing, permutation analyses were performed on both single SNP and haplotype models.Results: Eighteen SNPs in FANCD2 and 38 SNPs in FANCA passed MAF and HWE proportion requirements. For FANCD2, 4 SNPs spanning 67.5 Kb (rs7648104, rs2272125 [coding SNP], rs6786638 and rs644215), were significantly associated with taxane-induced neuropathy (p&lt;0.001) after controlling for multiple testing, with each SNP resulting in approximately a twofold increase in odds of severe taxane-induced neuropathy. Haplotype estimation showed that all 18 SNPs comprise a single haplotype. Two major (&gt;1% frequency) haplotypes were found. The frequencies of the risk haplotype in cases (patients with grade 3 or 4 neuropathy) and controls (patients with ≤ grade 2 neuropathy) were 0.25 and 0.15, respectively. Ordinal regression analyses were highly significant (p&lt;0.0005); patients with at least one copy of the risk haplotype had more than a twofold increased risk of grade 3 or 4 taxane-induced neuropathy (OR=2.2, 95% CI 1.44, 3.44). For FANCA, no SNPs or haplotypes were significantly associated with grade 3 or 4 neurotoxicity, either prior to or after correction for multiple testing.Conclusions: These results indicate that the Fanconi-Anemia pathway may be important for neurological sensitivity to taxanes, and that genotypic markers might be able to be used to identify patients at increased risk for severe taxane-induced neuropathy. Further studies will elucidate potential associations with survival outcomes.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2001.

Synergistic Effect of Lapatinib and the Class 1 HDAC Inhibitor SNDX-275 in Breast Cancer

Background: Inflammatory breast cancer (IBC) is a rare but aggressive form of primary breast cancer with high metastasis rates and poor survival outcomes in patients. Currently, no specific targeted therapy is available to improve patient outcomes, although agents (i.e. trastuzumab and lapatinib) targeting the human epidermal growth factor 2 (HER2) have shown promise in clinical trials. Histone deactylases (HDACs) represent another family of proteins for which inhibitors have been clinically validated and shown to inhibit proliferation of breast cancer cells in vitro and in vivo. In these studies we determined the single agent activity of the class 1 selective HDAC inhibitor entinostat (SNDX-275) in IBC cell models and whether SNDX-275 was synergistic with the HER2 targeted agent lapatinib.Methods: SNDX-275 activity was evaluated in SUM190, SUM149 and KPL-4 IBC cell lines using standard proliferation assays and compared to the non-IBC cell lines MDA-MB-231, SKBr3 and MCF-7. Apoptotic activity and cell cycle analysis were analyzed. SNDX-275 combination with lapatinib was initially determined in vivo in a HER2+ breast cancer model and subsequently in the SUM190, SUM149, KPL-4 IBC cells. For xenograft studies, athymic nude mice bearing human breast (BT474) tumor xenografts were treated with SNDX-275 at 15 or 30 mg/kg/day and lapatinib at 30 mg/kg/ 2xday or 75 mg/kg/ 2xday.Results: Significant anti-proliferative activity of SNDX-275 was observed in IBC (IC50, 250–500 nM) when compared with the non-IBC breast cancer cell lines MDA-MB-231, SKBr3, and MCF-7 (IC50 2–5 mM). Cell cycle analysis showed the onset of apoptosis in IBC cell lines (10%-17%); in the non-IBC cell lines, very little apoptosis occurred (0.8%–3.1%), although G1 stage arrest was seen in the non-IBC cell lines MDA-231 and MCF-7. The SNDX-275–induced apoptosis in IBC cell lines was dependent on caspase 9 rather than Caspase 8 cleavage indicating that the intrinsic apoptotic pathway is activated. The experiments with lapatinib demonstrated a significant benefit of the SNDX-275/lapatinib combination in both the BT474 xenograft study as well as the IBC cell lines tested. In the animal group that was treated with 15 mg/kg SNDX-275 plus 75 mg/kg lapatinib, synergistic effects were observed with tumor regression that was continued at least for 4 weeks after treatment was stopped. Similarly, synergistic anti-proliferative activity was found in almost all (4 of the 5) cell lines tested (SUM190, SUM149, KPL-4, and BT474). Investigation into the mechanism of SNDX-275–mediated apoptosis and the combined effects of lapatinib and SNDX-275 in IBC are under way. Our data demonstrate that HDACi as single agents and particularly in combination with HER2 targeted agents represent a promising new approach for clinical development in IBC breast cancer and patients with HER2-overexpressing breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3135.

Clinical Outcomes in Two Different Cohorts of Patients with Inflammatory Breast Cancer (IBC) Treated at the MD Anderson Cancer Center: The Experience of the Morgan Welch IBC Research Program and Clinic

BACKGROUND: Inflammatory Breast Cancer (IBC) is a rare but aggressive manifestation of primary breast cancer. Survival in patients with IBC is significantly lower than for non-IBC breast cancer patients. Appropriate diagnostic and treatment strategies provided by a specialized multidisciplinary team could impact the overall prognosis of the disease. We recently established an IBC research program and clinic including investigators from various disciplines solely dedicated to this disease. We sought to compare the characteristics and clinical outcomes of newly diagnosed IBC patients evaluated and treated using novel diagnostic and therapeutic approaches with an historical cohort of IBC patients treated at our institution.METHODS: We included 240 IBC patients treated at MD Anderson Cancer Center between January 1970 and August 2000. In this analysis we compared characteristics, 1 year progression free survival (PFS) and 1 year survival between the historic cohort and 47 patients diagnosed with IBC and seen at our IBC clinic between August 2007 and September 2008. The new patients are part of a prospective IBC registry. All of them had staging and monitoring with breast MRI and FDG-PET/CT. When indicated, they were treated with targeted therapies (e.g. trastuzumab and tipifarnib), that were not available for the patients in the old cohort. Descriptive statistics were used. Kaplan Meier product-limit method was used to calculate survival outcomes, groups were compare by log-rank test.RESULTS: Median age was similar in both cohorts (53 vs 51). In the new cohort 40% of the patients had evidence of distant metastasis at presentation. The most common sites were contralateral lymph nodes (26%), pleura (16%), bone (16%) and liver (11%). In the old cohort only 17% presented with stage IV. 38.7% of the new patients had Her2-neu amplified and 34%, triple receptor negative IBC. There was no difference in 1-year survival between the two groups (92.4% vs. 93.8%, p=0.637). For patients with stage III disease, the 1-year survival was 95% for both groups. The 1 year-PFS was 86.4% in the new cohort compared to 77.9% (p=0.43) in the old cohort. With a median follow up of 13 months, 51%of the patients in the new cohort are disease free and 87% are still alive.CONCLUSIONS: IBC is an aggressive but rare disease with poor prognosis. We have established a specialized IBC research program and clinic that introduces novel concepts and strategies in laboratory, imaging diagnostics and targeted therapies. This approach may accelerate our understanding of the biology, develop new therapeutic strategies and finally improve the outcome of IBC. Early results of this multidisciplinary approach show a modest, but not significant difference in outcome. We hope that with additional patients and longer follow-up a significant improvement in outcomes will become apparent.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5119.

The Molecular Anatomy of Breast Cancer Stroma; Independent Prognostic Role in ER-Positive and ER-Negative Cancers

BackgroundIn this paper we examine the various molecular components of a breast cancer stromal gene signature and correlate these with clinical phenotype and outcome including prognosis and response to preoperative chemotherapy.MethodsWe compared Affymetrix HGU133A-based gene expression profiles of 37 matching core needle biopsies (CNB) and fine-needle aspirations (FNA) from the same cancers. Genes over-expressed in CNB relative to the FNA were defined as the “stromal signature”. Gene expression data from 56 breast cancer cell lines, two separate neoadjuvant data sets (n=233, n=103), 3 independent cohorts of node negative, untreated patients (n=286, n=198, n=200) and 259 estrogen receptor-positive (ER+) tamoxifen-treated patients were used to assess the prognostic and predictive values of these genes in ER+ and ER- cancers separately. Univariate and multivariate Cox analyses were performed. Metagenes were defined as average expression of co-clustered genes.Results293 probe sets (206 genes) were significantly over-expressed in the CNBs (false discovery rate ≤ 0.001, fold-change ≥ 3). These genes overlapped with previously reported stromal signatures and fell into several co-expression clusters including a B-cell/Plasma Cell (B-cell), Dendritic cell, extracellular matrix (ECM), and TGFb-receptor metagenes. Interestingly, ER+ and ER- cancers showed a significantly different stroma-gene expression pattern, and many stromal genes were also differentially expressed between ER+ and ER- breast cancer cell lines. The ECM and TGFb metagenes had modest and variable prognostic value across different datasets in both ER groups. The Dendritic and B cell metagenes were highly co-expressed, but the B-cell metagene had more robust and consistent prognostic value. The B-cell metagene was statistically significant prognostic in univariate and multivariate analysis in ER+/High proliferative and ER- tumors, but it was not prognostic in ER+/Low proliferative tumors. In the 3 different node negative, untreated patient cohorts, the ER+/High proliferative cancers in the lowest B-cell metagene tertile had 10-year distant metastasis free survival (DMFS) of 0.18 (0.07-0.46), 0.22 (0.06-0.75), and 0.44 (0.21-0.92) compared to 0.71 (0.54-0.94), 0.89 (0.71-1.00) and 0.89 (0.71-1.00) in the highest tertile. Among the ER- cancers, the lowest B cell metagene group had 10-year DMFS of 0.57 (0.44-0.75), 0.63 (0.48-0.83), and 0.44 (0.25-0.76) compared to 0.93 (0.81-1.00), 0.83 (0.64-1.00) and 0.83 (0.58-1.00) in the highest B-cell metagene group in each prognostic dataset, respectively. The B-cell metagene was also prognostic in univariate (HR 0.83 (0.71-0.98) p=0.03) and multivariate (HR 0.80 (0.68-0.94) p=0.007) analysis in the Tamoxifen-treated cohort. None of the above stromal metagenes showed reproducible association with response to chemotherapy.ConclusionsThe B-cell/Plasma cell metagene component of the “stroma-related genes” is a robust and reproducible prognostic marker in ER+/High proliferative and also in ER- cancers. Other stromal genes are variably expressed in ER+ and ER- tumors and many are also expressed by neoplastic cells in culture and by primary tumors and carry less reproducible prognostic value.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 105.

Thomboembolic Events in Patients with Breast Cancer: A Population Based Study

BACKGROUND: Thromboembolic events (TEEs) are common in patients with cancer. Metastatic disease, treatment and comorbidities have been associated with increased risk. In this population-based study we sought to evaluate the risk factors and the prevalence of different TEEs in patients with breast cancer.METHODS: Retrospective cohort study using the SEER-Medicare linked database. Patients with breast cancer (stage I-IV) diagnosed from 1992-2002, who were 66 and older, and had full coverage of Medicare A and B were identified. ICD-9, HCPCS codes were used to identify different TEEs that occurred within one year of the breast cancer diagnosis. We identified pulmonary embolism (PE), deep venous thrombosis (DVT)/thrombophlebitis, other TEEs, as well as the use of chemotherapy, radiotherapy, surgery and comorbidities. Analyses were conducted using descriptive statistics and logistic regression.RESULTS: 71,864 patients were included. Age groups were distributed as follows: 66-70 (24.1%), 71-75 (26.4%), 76-80 (23.2%), &gt;80 (26.3%). At diagnosis 52.4% of patients had stage I, 35.2% stage II, 6.6% stage III and 5.8% stage IV. 66.8% of the patients had ER-positive breast cancer. Within one year of diagnosis, 2652 (3.7%) of patients developed a TEE, including 800 patients with at least two events. 3565 total number of events were observed. A total of 596 (0.85%) PEs, 1252 (1.74%) DVT/thrombophlebitis, and 1717 (3.39%) other TEEs were identified. In the univariate analysis race, marital status, education and poverty level, geographical location, stage, tumor grade, estrogen receptor status, comorbidities, as well as surgical modality, radiation therapy and chemotherapy use, were associated with the development of any TEE.After adjusting for potential confounders, the development of any TEE was associated with ER-positive tumors (OR 1.20, 95% CI 1.07-1.34), stage II vs. I (OR 1.22, 95% CI 1.11-1.35), stage III vs. I (OR 1.63, 95% CI 1.40-1.90), stage IV vs. I (OR 2.16, 95% CI 1.82-2.57), chemotherapy (OR 2.02, 95% CI 1.82-2.23), radiotherapy (OR 1.39, 95% CI 1.27-1.52), comorbidity score (OR 1.19, 95% CI 1.08-1.32 and OR 1.74, 95% CI 1.54-1.96 for score 1 and 2 respectively), and type of surgery (OR 1.25, 95% CI 1,13-1.38 for mastectomy vs. breast conservation surgery and OR 1.23, 95% CI 1.02-1.49 for no surgery vs. breast conservation surgery). Borderline association was seen with age (using 66-70 as a reference value, the ORs for the 71-75, 76-80 and &gt;80 year old categories were: 1.14, 95%CI 1.02-1.28; 1.17, 95% CI 1.04-1.32; and 1.15, 95% CI 1.01-1.29 respectively). Relatively similar estimates were seen for the analysis of PE, DVT/thrombophlebitis and other TEEs.CONCLUSION: 3.7% of patients in this cohort developed a TEE within one year from breast cancer diagnosis. Age, stage, type of treatment, comorbidities and receptor status were associated with the development of TEEs. To the best of our knowledge this is the largest cohort of patients older than 66years old, in which the patterns and risk factors associated with TEEs are analyzed. Whether these observations apply to patients younger than age 65, remains to be established.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2053.

Evaluation of the Predictive Performance and Regimen Specificity of a 30-Gene Predictor of Pathologic Complete Response in a Prospective Randomized Neoadjuvant Clinical Trial for Stage I-III Breast Cancer

Purpose: To prospectively evaluate in a randomized trial if a previously reported multigene predictor of pathologic complete response (pCR) to preoperative weekly paclitaxel and fluorouracil-doxorubicin-cyclophosphamide (T/FAC) chemotherapy can accurately predict pCR to neoadjuvant T/FAC chemotherapy, and if it also predicts pCR to FAC only chemotherapy. Furthermore, it is unknown if the T/FAC regimen is superior to 6 courses of FAC; therefore we compare the pCR rates for patients who receive T/FAC versus FACx6 preoperative chemotherapy.Materials and Methods: Patients with stage I-III breast cancer (n=273) were randomly assigned to receive either 12 courses of weekly paclitaxel followed by 4 courses of FAC (T/FAC, n=138), or 6 courses of FAC (FACx6, n=135) neoadjuvant chemotherapy. All patients underwent a pretreatment FNA biopsy of the tumor for gene expression profiling on oligonucleotide microarrays, and treatment response prediction (pCR versus residual disease, RD) was performed using the multigene predictor. Predicted and observed pathologic responses were compared independently in the two treatment arms.Results: The pCR rate was 19% with T/FAC and 9% with FACx6 (p&lt;0.05). In the T/FAC arm, the positive predictive value (PPV) of the genomic predictor was 38% (95%CI:21-56%), the negative predictive value (NPV) 88% (CI:77-95%), sensitivity 63% (CI:38-84%), specificity 72% (CI:60-82%), and the AUC 0.711. In the FAC only treatment arm, the PPV was 9% (CI:1-29%), the NPV 92% (CI:83-97%), sensitivity 29% (CI:4-71%), specificity 75% (CI:64-84%), and the AUC 0.584. This suggests that the genomic predictor is regimen-specific. In a multivariate analysis including age, tumor size, nodal status, histologic grade, HER2 and estrogen receptor (ER) status and the genomic predictor, only ER status was a significant predictor of pCR.Discussion: Pathologic complete response rate was significantly higher in the T/FAC arm compared to the FACx6 arm indicating a higher efficacy of the paclitaxel containing arm. Patients who were predicted to achieve pCR to T/FAC had a significantly higher pCR rate (38%) than unselected patients (19%) or patients predicted to have RD (12%) when treated with this regimen. These results confirm that the multigene predictor can identify patients with greater than average sensitivity to T/FAC chemotherapy.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 101.

Brain Metastases in Women with Inflammatory Breast Cancer (IBC): Incidence, Treatment and Outcome

Background: Brain metastases are an uncommon metastatic recurrence site in breast cancer with a median incidence of approximately 6% in unselected populations. Inflammatory breast cancer (IBC) is an aggressive disease associated with dismal outcome. The purpose of this study was to determine the incidence of and survival following brain metastases among women with IBC.Material and Methods: Two hundred and six women with newly diagnosed stage III or IV IBC diagnosed between the period of between 2003 and 2008 were identified in a prospectively maintained IBC database at the MD Anderson Cancer Center. Cumulative incidence of brain metastases was computed. Cox proportional hazards models were fitted to explore factors that predict for the development of brain metastases. Survival was computed using the Kaplan-Meier product limit method.Results: Median follow-up was 20 months. Eighty three (40.3%) women had de-novo stage IV disease and 123 (59.7%) had stage III disease at diagnosis. Thirty-three (16%) patients developed brain metastases with a cumulative incidence at 1 and 3 years of 2.7% and 22% respectively. Eleven (5.3%) patients developed brain metastases as the first site of recurrence with cumulative incidence at 1 and 3 years of 1.6% and 6.7% respectively. In the multivariable model, no specific factor was observed to be significantly associated with time to brain metastases, including HER-2 status. Median overall survival for the whole cohort was not reached. 3-year overall survival for the whole cohort was 78% (95% CI 69%-86%). Median survival following a diagnosis of brain metastases for all women who developed brain metastases or those who developed brain metastases as the first site of recurrence was 6 months.Conclusion: In this single-institutional study, women with IBC demonstrated a high early incidence of brain metastases associated with poor survival. As such IBC may be an ideal cohort to target screening procedures for brain metastases and/or enrollment of these women in clinical trials evaluating additional adjuvant preventive strategies.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2102.