Axillary Nodal Response to Neoadjuvant T-DM1 Combined with Pertuzumab in a Prospective Phase II Multi-Institution Clinical Trial

BACKGROUND

Patients with ERBB2 (HER2)-positive breast cancer experience high pathologic complete response (pCR) rates after standard neoadjuvant anti-HER2 systemic therapy. We examined axillary pathologic nodal response to neoadjuvant dual HER2-targeted therapy alone, based on breast pathologic response, in a multi-institution clinical trial.

STUDY DESIGN

Patients with HER2-positive breast cancer were enrolled to a phase II single-arm trial, which administered 6 cycles of neoadjuvant trastuzumab emtansine (T-DM1) plus pertuzumab. Rates of pathologic nodal disease (ypN) in patients who were clinically node-negative (cN0) and node-positive (cN1) were analyzed, by residual breast disease (pCR and residual cancer burden [RCB] I to III).

RESULTS

One hundred fifty-eight patients completed preoperative treatment and proceeded to surgery. Of 92 patients who were cN0, 48 (52.2%) and 10 (10.9%) experienced breast pCR and RCB I, respectively. Of these, 100% were ypN0. Of 34 with RCB II to III, 26 (76.5%) were ypN0. Of 30 patients who were cN1 with breast pCR, 100% were ypN0; of the 12 patients who were cN1 with RCB I, 66.7% were ypN0; and of the 24 patients who were cN1 with RCB II to III, 25% were ypN0. ypN0 rates were significantly different between patients who did and did not experience a pCR, in both cN0 (p = 0.002) and cN1 (p < 0.001) subgroups.

CONCLUSIONS

Patients with HER2-positive breast cancer treated with dual HER2-targeted therapy who experienced a breast pCR or RCB I response were frequently ypN0. These findings support future trials considering omission of axillary surgical staging for patients with HER2-positive breast cancer in neoadjuvant trials of active HER2-targeted regimens, particularly if they experience breast pCR or RCB I.

Abstract P3-03-12: Risk of recurrence with adjuvant endocrine therapy in real world patients with hormone receptor positive/human epidermal growth factor receptor-negative early breast cancer: a US database analysis

Background The recommended 5-10 years of adjuvant endocrine therapy (ET) as standard of care has improved outcomes in patients with HR+/HER2− early breast cancer (EBC); however, risk of recurrence persists. The monarchE study demonstrated improvement in invasive disease-free survival (iDFS) with abemaciclib in node-positive, high-risk EBC, the majority of which were stage III (Johnston SRD, et al. J Clin Oncol. 2021;38:3987); however, monarchE’s relatively short follow-up time to date only allowed for observation of early recurrences—longer follow-up is needed to evaluate late recurrences. Risk of recurrence is a concern for patients with all stages of EBC (Pan H, et al. N Engl J Med. 2017;377:1836). We assessed the risk of recurrence in a real-world setting among patients with stage II-III HR+/HER2− EBC after initiation of adjuvant ET. Methods This was a retrospective analysis of ConcertAI’s deidentified electronic medical records data set among patients treated from January 1, 1995, to April 30, 2021. The cohort included stage II-III patients with HR+/HER2− EBC who underwent surgery and initiated adjuvant ET (if IIIB or IIIC, confirmation was required on residual tumor status). Patients were from academic and community oncology clinics across the US. Data were missing from the database for some variables; thus, percentages may not add up to 100%. iDFS was assessed to determine the risk of disease recurrence, death, or second primary tumor and was defined as the time interval between start of ET and first iDFS event. Kaplan-Meier methods were used to estimate cumulative probabilities of experiencing an iDFS event at 5 and 10 years from the start of ET. Results A total of 3133 patients (98.8% female) with stage II-III HR+/HER2− EBC were included in the analysis. The median follow-up time was 68.1 months. The median age was 59 years; 22.2% of female patients were pre/perimenopausal and 44.7% were postmenopausal; 80.9% of all patients had stage II disease, while 19.1% had stage III disease. In total, 42.1% and 3.7% of those with stage II and III disease had no nodal involvement, respectively. Overall, 51.2% of patients did not receive radiotherapy, and 59.5% of patients did not receive (neo)adjuvant chemotherapy. In the total sample, the 5- and 10-year risk of an iDFS event was 26.1% and 45.0%, respectively. In patients with stage II disease, the 5- and 10-year risks were 22.7% and 40.5%, respectively, and 40.4% and 62.9% among stage III. Conclusions These real-world data demonstrate that the risk of recurrence with adjuvant ET, particularly in those with stage II EBC, is higher than reported in many randomized controlled trials. Importantly, our data show that, in the real-world setting, the stage II population represents a significant proportion of patients (nearly 4 times more than stage III). These findings confirm and underscore the clear unmet need in this population and highlight the need for improved treatment options in this broader EBC population. The NATALEE study will investigate ribociclib + ET in a broad population of patients including stage II and stage III HR+/HER2− EBC with high-risk features, regardless of nodal status.

Citation Format: Joyce O’Shaughnessy, Denise Yardley, Lowell Hart, Pedram Razavi, Stephanie L. Graff, Jenifer Wogen, Courtney McDermott, Pierre-Alexandre Dionne, Sina Haftchenary, Purnima Pathak, Sara Tolaney. Risk of recurrence with adjuvant endocrine therapy in real world patients with hormone receptor positive/human epidermal growth factor receptor-negative early breast cancer: a US database analysis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-03-12.

Abstract PD18-01: Adjuvant Trastuzumab Emtansine Versus Paclitaxel plus Trastuzumab for Stage I HER2+ Breast Cancer: 5-year results and correlative analyses from ATEMPT (TBCRC033)

Background: The ATEMPT trial primary analysis found that one year of adjuvant trastuzumab emtansine (T-DM1) achieved a 3-year iDFS of 97.8% for patients with stage I HER2+ breast cancer, but was not associated with fewer clinically relevant toxicities (CRTs) compared with paclitaxel and trastuzumab (TH). In this end-of-study analysis, we report 5-year survival outcomes and correlative analyses from the trial. Methods: Patients with stage I centrally confirmed HER2+ breast cancer were randomly assigned 3:1 to adjuvant T-DM1 for one year or TH and received T-DM1 3.6 mg/kg IV every 3 weeks for 17 cycles or paclitaxel 80 mg/m2 IV with weekly trastuzumab IV followed by trastuzumab for 9 months. The co-primary objectives were to compare the incidence of CRTs between the 2 arms and to evaluate iDFS in patients receiving T-DM1. To investigate proteomic correlates of recurrence, spatial proteomic analyses were performed on samples from 13 patients experiencing iDFS events (cases) and 24 matched controls using the NanoString GeoMx Digital Spatial Profiler. The impact of HER2 heterogeneity on outcomes was investigated among 17 cases and 51 matched controls by fluorescence in-situ hybridization (FISH). HER2 genetic heterogeneity was assessed by scrutinizing the whole tumor area and defined as the occurrence of HER2 gene amplification in &gt;5% but &lt; 50% invasive tumor cells. The risk of recurrence was evaluated centrally with the HER2DX genomic assay from 225 primary tumor samples. Germline whole genome sequencing (WGS) was conducted among 55 patients experiencing T-DM1-induced thrombocytopenia and/or bleeding and 55 matched controls to identify genomic correlates for this side effect. Results: A total of 497 patients who initiated protocol therapy were included in this analysis (383 T-DM1 and 114 TH). After a median follow up 5.8 years, among patients receiving T-DM1 there were a total of 11 iDFS events, with 3 distant recurrences. The 5-year iDFS for T-DM1 was 97.0% (95% CI, 95.3-98.8%), the 5-year recurrence-free interval (RFI) was 98.6% (95% CI: 97.4-99.8%) and the 5-year overall survival (OS) for T-DM1 was 97.8 % (95% CI, 96.3-99.3%). Although the study was not powered to evaluate the efficacy of TH, among the 114 patients receiving TH, a total of 9 iDFS events were observed, including 2 distant events; the 5-year iDFS with TH was 91.3% (95% CI: 86.0-96.9%), 5-year RFI was 93.3% (95% CI: 88.6-98.2%) and 5-year OS was 97.9% (95% CI: 95.2-100%). A total of 56 samples were evaluable for heterogeneity analyses, among which 14% (n=8) harbored HER2 genetic heterogeneity. Spatial proteomic analyses found that NF1 (adjusted p=0.72 × 10-6) and CTLA-4 (adjusted p=0.15 × 10-3) were significantly upregulated in primary samples from cases, while cleaved caspase 9, CD25, GITR, ICOS, p53 and PD-L2 were significantly upregulated in controls (all with adjusted p&lt; 0.05). Germline WGS found that the top gene associations with thrombocytopenia and thrombocytopenia or bleeding were ALMS1 (p=0,19 × 10-3) and APBA3 (p=0,23 × 10-3), respectively, although none reaching the threshold for genome wide significance. rs62143195 and rs114169776 were the top single nucleotide polymorphisms associated with thrombocytopenia and thrombocytopenia or bleeding, respectively. Data on the impact of HER2 heterogeneity and of HER2DX score on survival outcomes will be presented. Conclusion: With longer follow-up, adjuvant T-DM1 confirmed outstanding long-term outcomes among patients with stage I HER2+ breast cancer, demonstrating a 5-year RFI of 98.6%. Spatial proteomic analyses identified a potential association between NF1 and CTLA-4 expression with recurrence. Details on the impact of HER2 heterogeneity and HER2DX assay on prognosis will be presented.

Citation Format: Paolo Tarantino, Nabihah Tayob, Chau T Dang, Denise Yardley, Steven J. Isakoff, Vicente Valero, Meredith Faggen, Therese Mulvey, Ron Bose, Douglas Weckstein, Antonio C. Wolff, Katherine Reeder-Hayes, Hope Rugo, Bhuvaneswari Ramaswamy, Dan Zuckerman, Lowell Hart, Vijayakrishna K. Gadi, Michael Constantine, Kit Cheng, Audrey Merrill Garrett, Paul K. Marcom, Kathy S. Albain, Patricia DeFusco, Nadine Tung, Blair Ardman, Rita Nanda, Rachel C. Jankowitz, Mothaffar Rimawi, Vandana Abramson, Paula R. Pohlmann, Catherine Van Poznak, Andres Forero-Torres, Minetta C. Liu, Kathryn Ruddy, Yue Zheng, Romualdo Barroso-Sousa, Adrienne Waks, Michelle K. DeMeo, Molly K. DiLullo, Giuseppe Curigliano, Harold Burstein, Ann Partridge, Eric Winer, Giuseppe Viale, Winnie Hui, Elizabeth A. Mittendorf, Bryan P. Schneider, Aleix Prat, Ian Krop, Sara Tolaney. Adjuvant Trastuzumab Emtansine Versus Paclitaxel plus Trastuzumab for Stage I HER2+ Breast Cancer: 5-year results and correlative analyses from ATEMPT (TBCRC033) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD18-01.

Abstract PD18-02: Adjuvant Paclitaxel and Trastuzumab Trial (APT) for Node-Negative, Human Epidermal Growth Factor Receptor 2–Positive (HER2+) Breast Cancer: final 10-year analysis

Background: The APT trial evaluated the activity of adjuvant paclitaxel and trastuzumab (TH) among patients with small, node negative HER2+ breast cancer. This regimen showed a 7-year invasive disease-free survival (iDFS) of 93%, a recurrence-free interval (RFI) of 97.5% with only four (1.0%) distant recurrences, and a 7-year overall survival (OS) of 95%. In this end-of-study analysis, we report the survival outcomes at 10 years and assess the role of HER2DX testing in predicting long-term outcomes with adjuvant TH.

Methods: APT was a single-arm multicenter investigator-initiated phase II study in which patients with HER2+ breast cancer with tumors ≤3 cm and negative nodes (one single micrometastatic node allowed) received IV weekly paclitaxel (80 mg/m2) with IV weekly trastuzumab for 12 weeks, followed by IV trastuzumab for 9 months. The primary endpoint was 3-year iDFS. Here we report 10-year iDFS, RFI, breast cancer–specific survival (BCSS) and OS. In an exploratory analysis, the risk of recurrence was evaluated with the HER2DX genomic assay.

Results: A total of 410 patients were enrolled from October 2007 to September 2010, of which 406 started the study treatment and were included in the intent to treat analysis. Median age at enrollment was 55 years (range, 24 to 85 years), and most patients (67%) had hormone receptor (HR)-positive disease. Fifty percent of patients had tumors 1.0 cm or smaller and only 9% of patients had tumors between 2 cm to 3 cm. Mean tumor size was 1.1 cm. After a median follow-up of 10.2 years (122 months), 36 iDFS events were observed, consistent with a 10-year iDFS of 89.7% (95% CI, 86.3%-93.1%). Ten-year iDFS was 90.2% (95% CI, 86.3%-94.3%) and 88.5% (95% CI, 82.4%-95.1%) for patients with HR-positive and HR-negative tumors at baseline, respectively. 10-year RFI was 96.8% (95% CI, 95.0%-98.7%), 10-year OS was 94.2% (95% CI, 91.6%-96.8%) and 10-year BCSS was 99.1% (95% CI, 98.1%-100.0%). Of the iDFS events observed in the trial, 6 were non-breast cancer related deaths and 9 were contralateral tumors, all but one locally found to be HER2-negative upon biopsy (Table 1). Among patients experiencing an iDFS event, 7 patients (1.7%) had distant recurrences, including 1 with a T2 tumor, 3 with a T1c tumor and 3 with a T1b tumor. At baseline, 6 of them had HR-positive disease, 1 had HR-negative disease, and 6 had high-grade disease. Upon biopsy of metastatic lesions, 5 of the 7 distant recurrences were locally found to be HER2+, 1 was HER2-negative and 1 had unknown HER2 status. HER2DX testing was conducted on available baseline archival tumor tissue and analyses of patients’ survival outcomes based on the HER2DX score will be presented.

Conclusion: After 10 years of follow-up, adjuvant TH confirmed excellent long-term outcomes for small, node-negative HER2+ breast cancer, with a 10-year RFI of 96.8% and a 10-year BCSS of 99.1%.

Table 1: iDFS events with adjuvant paclitaxel plus trastuzumab after 10.2 years of follow up

Citation Format: Sara Tolaney, Paolo Tarantino, Noah Graham, Nabihah Tayob, Chau T Dang, Denise Yardley, Beverly Moy, Paul K. Marcom, Kathy S. Albain, Hope Rugo, Matthew Ellis, Iuliana Shapira, Antonio C. Wolff, Lisa Carey, Romualdo Barroso-Sousa, Michelle K. DeMeo, Molly K. DiLullo, Ann Partridge, Adrienne Waks, Clifford Hudis, Ian Krop, Harold Burstein, Aleix Prat, Eric Winer. Adjuvant Paclitaxel and Trastuzumab Trial (APT) for Node-Negative, Human Epidermal Growth Factor Receptor 2–Positive (HER2+) Breast Cancer: final 10-year analysis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD18-02.

Abstract OT2-17-01: Phase 1 trial of anthracycline chemotherapy in combination with CD40 agonist and Flt3 ligand in metastatic triple-negative breast cancer

Background: Only a subset of patients with metastatic triple-negative breast cancers (TNBC) demonstrate response to FDA approved PD-1 immune checkpoint blockade (ICB), and few have durable responses. Data suggests that breast cancers have defects in antigen presentation and that antigen presenting cells especially the DC1 subtype of dendritic cells (DCs) are required for response to ICB. CD40 agonists activate antigen presenting cells including DCs and B cells and also repolarize macrophages to an anti-tumor phenotype. Flt3 ligand is a growth factor that increases differentiation and expansion of DCs. We recently demonstrated in pre-clinical TNBC models that the combination of liposomal-doxorubicin chemotherapy, a CD40 agonist, and a Flt3 ligand improves outcomes compared to alternate combinations. Methods: This is a single arm phase I pilot study of liposomal-doxorubicin, CDX-1140 (CD40 agonist), and CDX-301 (Flt3 ligand) combination therapy in patients with metastatic or unresectable locally advanced metastatic TNBC. Patients will be randomized to 3 lead-in arms (triplet therapy, doublet immunotherapy only, or liposomal-doxorubicin only) for 1 cycle prior to receiving triplet therapy with fresh tissue biopsies before and after the lead-in treatment. CDX-301 will be discontinued after 2 cycles; liposomal-doxorubicin and CDX-1140 will be continued until disease progression or clinically limiting toxicities. Primary endpoint is determination of a recommended phase 2 dose based on treatment-related adverse events including dose-limiting toxicities. Secondary endpoints include anti-tumor immune response after triplet therapy, after immunotherapy alone, and after liposomal-doxorubicin alone; median progression-free survival, overall response rate, duration of response, and clinical benefit rate. Key eligibility criteria are unresectable stage III or stage IV TNBC (ER ≤10%, PR ≤10%, HER2/neu negative), 1st to 3rd line metastatic treatment setting (1st line patients need to be PD-L1 negative by 22C3 assay), measurable disease by RECIST 1.1 criteria, consent for pre-treatment and on-treatment biopsies of amenable soft tissue tumor lesions, no prior treatment with an anti-CD40 antibody or a Flt3 ligand, no anthracycline treatment in the metastatic setting, no prior progression while on anthracycline-based therapy or within 6 months of completing neoadjuvant chemotherapy, and no history of non-infectious pneumonitis or current pneumonitis. This trial will enroll up to 45 patients across multiple sites (NCT05029999).

Citation Format: Sangeetha Reddy, Meredith Carter, Isaac Chan, Nisha Unni, Namrata Peswani, Dawn Klemow, Samira Syed, Shahbano Shakeel, Farjana Fattah, Chul Ahn, Yisheng Fang, Heather McArthur, Nicole Sinclair, Michael Yellin, Denise Yardley, Nan Chen, Joyce O’Shaughnessy, Rita Nanda, Suzanne D. Conzen, Carlos Arteaga. Phase 1 trial of anthracycline chemotherapy in combination with CD40 agonist and Flt3 ligand in metastatic triple-negative breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT2-17-01.

Correlation between work productivity loss and EORTC QLQ-C30 and -BR23 domains from the MONALEESA-7 trial of premenopausal women with HR+/HER2− advanced breast cancer

Background:

The phase III MONALEESA-7 trial (NCT02278120) assessed ribociclib + endocrine therapy (ET) versus ET in premenopausal women with HR+/HER2− advanced breast cancer (ABC). The relationship between work productivity loss (WPL) and domains of European Organisation for Research and Treatment of Cancer Quality of Life (EORTC QLQ-C30) and the breast cancer (BC)-specific module (QLQ-BR23) has not been explored in ABC. In this post hoc analysis (data cutoff, November 30, 2018), we assessed the correlation between the WPL component of the Work Productivity and Activity Impairment: General Health (WPAI:GH) questionnaire and EORTC QLQ-C30/BR23 domains.

Methods:

We analyzed EORTC and WPAI:GH data from 329 patients in both treatment arms of MONALEESA-7 who were employed during the trial. Separate univariable mixed-model repeated measures (MMRM) regression models were fitted for each domain, with WPL as dependent variable and each EORTC domain score as a single fixed-effect covariate. Linear and quadratic relationships were considered based on the Akaike information criterion. Next, two separate multivariable MMRM regression models were fitted with WPL a dependent variable and all QLQ-C30/BR23 domain scores as fixed-effect covariates. The strength of correlation between WPL and EORTC domains was assessed in terms of minimally important differences for the QLQ-C30/BR23 modules.

Results:

Our univariable analysis showed that greater WPL was statistically significantly associated with lower levels of overall quality of life (QoL) and other functional domains and with higher levels of all symptomatic domains of the QLQ-C30/BR23 modules. Our multivariable analysis determined that this correlation was primarily driven by changes in QoL; physical, role, social, and future perspective domains; and BC-specific symptomatic domains.

Conclusion:

This analysis determined the QoL domains that correlate with WPL in premenopausal patients with HR+/HER2− ABC. These results may inform prognostic tools to identify and characterize patients with greater risk for WPL and help design interventional strategies to minimize WPL.

Long-term efficacy and safety of addition of carboplatin with or without veliparib to standard neoadjuvant chemotherapy in triple-negative breast cancer: 4-year follow-up data from BrighTNess, a randomized phase 3 trial

BACKGROUND

Primary analyses of the phase 3 BrighTNess trial showed addition of carboplatin with/without veliparib to neoadjuvant chemotherapy significantly improved pathological complete response (pCR) rates with manageable acute toxicity in patients with triple-negative breast cancer (TNBC). Here, we report 4.5-year follow-up data from the trial.

DESIGN

Women with untreated stage II-III TNBC were randomized (2:1:1) to paclitaxel (weekly for 12 doses) plus either: (a) carboplatin (every 3 weeks for four cycles) plus veliparib (twice daily); (b) carboplatin plus veliparib placebo; or (c) carboplatin placebo plus veliparib placebo. All patients then received doxorubicin and cyclophosphamide (AC) every 2‒3 weeks for four cycles. The primary endpoint was pCR. Secondary endpoints included event-free survival (EFS), overall survival (OS), and safety. Since the co-primary endpoint of increased pCR with carboplatin plus veliparib with paclitaxel versus carboplatin with paclitaxel was not met, secondary analyses are descriptive.

RESULTS

Of 634 patients, 316 were randomized to carboplatin plus veliparib with paclitaxel, 160 to carboplatin with paclitaxel, and 158 to paclitaxel. With median follow-up of 4.5 years, the hazard ratio [HR] for EFS for carboplatin plus veliparib with paclitaxel versus paclitaxel was 0.63 (95% confidence interval [CI] 0.43‒0.92, P=0.02), but 1.12 (95% CI 0.72‒1.72, P=0.62) for carboplatin plus veliparib with paclitaxel versus carboplatin with paclitaxel. In post hoc analysis, HR for EFS was 0.57 (95% CI 0.36‒0.91, P=0.02) for carboplatin with paclitaxel versus paclitaxel. OS did not differ significantly between treatment arms, nor did rates of myelodysplastic syndromes, acute myeloid leukemia, or other secondary malignancies.

CONCLUSION

Improvement in pCR with addition of carboplatin was associated with long-term EFS benefit with a manageable safety profile, and without increasing the risk of second malignancies, while adding veliparib did not impact EFS. These findings support the addition of carboplatin to weekly paclitaxel followed by AC neoadjuvant chemotherapy for early stage TNBC.

Abstract PS18-34: Physician adoption and molecular landscape of next-generation sequencing in breast cancer patients from community-based clinics

Background: Molecular biomarkers such as the expression status of hormone receptors (HR) and HER2 influence disease diagnosis, prognosis, and treatment decisions in breast cancer patients. Recent advances in genetic sequencing technologies and targeted therapies have revealed additional actionable biomarkers including PIK3CA, ESR1, and BRCA1/2; however, it remains unclear whether physicians in community-based clinics are universally adopting molecular profiling practices. Here, we describe the utility of next generation sequencing (NGS) in the care of breast cancer patients in community-based clinics with a focus on physician behaviors and molecular landscapes.

Methods: Sarah Cannon provides clinical research services to medical oncology practices who order NGS panels as part of standard of care. Genospace, Sarah Cannon’s web-based precision medicine platform, links NGS test results with electronic medical records to identify and analyze clinico-genomic data of molecularly-profiled cancer patients. Here, a total of 2,673 NGS reports from 2,313 unique patients dated between January 2014 and December 2019 were analyzed. Hormone statuses were abstracted from physician notes using natural language processing capabilities and manual abstraction. Linear regression modeling was used for statistical analysis.

Results: Physician ordering of NGS tests for breast cancer patients increased 6.3-fold from 2014 to 2019. Ordering of plasma-based NGS tests increased from 0.6% (versus 99.4% tissue) in 2014 to 47.0% (versus 53.0% tissue) in 2019. The time from initial diagnosis to NGS results increased from a median of 1008 days in 2015 to 1296 days in 2019 (p &lt; 0.05), while the time from specimen collection to NGS test results (tissue only) decreased from 53 days in 2015 to 28 days in 2019 (p &lt; 0.01). The majority of NGS-tested breast cancer patients were HR+/HER2- (62.6%), followed by HR-/HER2- (21.5%), HR+/HER2+ (8.4%), HR-/HER2+ (4.4%), and HER2 equivocal (3.0%). Plasma-based NGS testing was utilized more commonly in HR+ cancers (43.4% of HR+; 25.3% of HR-). In agreement with published studies, BRCA1 alterations were enriched in HR- cancers (1.7% of HR+; 6.6% of HR-) and BRCA2 alterations were enriched in HR+ cancers (6.4% of HR+; 3.2% of HR-). Amplifications in CCND1 (21.7% of HR+; 2.2% of HR-) and FGFR1 (18.1% of HR+; 6.2% of HR-) were also enriched in HR+ cancers, as were mutations in ESR1 (18.9% of HR+; 1.0% of HR-). PIK3CA mutations occurred most frequently in HR+ cancers (45.0%), but were also present in HR- cancers (20.9%). TP53 mutations were comparatively high in HR- cancers (42.9% of HR+; 94.8% of HR-).

Conclusions: The usage of NGS for the care of breast cancer patients is increasing in community settings. Plasma-based NGS tests are ordered more frequently in HR+ cancers, likely as a result of difficult-to-biopsy and poor yield bone-only disease. Despite increased testing frequencies, NGS tests are ordered later-in-care which may be a reflection of earlier diagnosis or the development of more efficacious standard of care therapies in front line settings. The tissue specimens sent for sequencing are collected closer to the test date, indicating improved tissue processing systems and prioritization of fresh specimen collection for NGS testing. Overall, physicians are adopting NGS-testing as part of standard of care for breast cancer patients in the community setting and are discovering actionable mutations.

Frequency of detection of molecular biomarkers in NGS-tested breast cancer patientsTissueTissueTissueTissuePlasmaPlasmaPlasmaPlasmaGeneAlterationHR+/HER2-HR-/HER2-HR+/HER2+HR-/HER2+HR+/HER2-HR-/HER2-HR+/HER2+HR-/HER2+ERBB2Amp1.1%0.5%45.4%67.9%0.0%0.8%10.4%45.5%CCND1Amp21.3%1.7%21.8%5.1%7.5%1.7%5.2%0.0%MYCAmp9.3%15.5%18.5%17.9%1.3%5.8%1.3%9.1%FGFR1Amp17.4%6.8%18.5%3.8%6.5%3.3%2.6%0.0%PIK3CAMutation43.8%19.1%49.6%32.1%49.5%25.0%50.6%30.3%ESR1Mutation19.4%1.2%13.4%0.0%41.7%4.2%31.2%0.0%BRCA1Mutation1.9%7.2%0.8%3.8%5.1%5.0%2.6%9.1%BRCA2Mutation6.7%3.6%5.9%1.3%8.8%5.8%14.3%3.0%ERBB2Mutation3.4%1.4%11.8%6.4%9.5%1.7%15.6%12.1%TP53Mutation42.2%94.7%51.3%93.6%65.8%96.7%68.8%93.9%PTENMutation8.8%10.6%2.5%3.8%12.6%10.8%7.8%6.1%PALB2Mutation1.6%1.2%0.8%0.0%0.2%0.0%0.0%0.0%MTORMutation0.7%0.2%0.8%0.0%2.7%0.0%0.0%0.0%ARID1AMutation9.0%4.8%12.6%2.6%11.0%11.7%7.8%3.0%KRASMutation3.2%3.1%0.8%2.6%6.5%8.3%5.2%6.1%AKT1Mutation6.5%3.4%2.5%1.3%7.5%6.7%1.3%0.0%n=856n=414n=119n=78n=602n=120n=77n=33

Citation Format: Emma Sturgill, Amanda Misch, Rebecca Lachs, Carissa Jones, Dan Schlauch, Suzanne Jones, Mythili Shastry, Denise Yardley, Howard Burris, David Spigel, Erika Hamilton, Andrew McKenzie. Physician adoption and molecular landscape of next-generation sequencing in breast cancer patients from community-based clinics [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 PS18-34.

Correction to: A window-of-opportunity trial of the CXCR1/2 inhibitor reparixin in operable HER-2-negative breast cancer

An amendment to this paper has been published and can be accessed via the original article.

Abstract PD10-02: Patient reported outcomes from the adjuvant trastuzumab emtansine (T-DM1) vs. paclitaxel + trastuzumab (TH) (ATEMPT) trial (TBCRC 033)

Purpose: The ATEMPT trial sought to determine if adjuvant T-DM1 (every 3 wks for 1 yr) for Stage I HER2 positive breast cancer is better tolerated than TH (paclitaxel weekly x 12 wks with 1 yr of trastuzumab). Here we compare patient-reported outcomes (PROs) including quality of life (QOL), specific symptoms, and work productivity between the two treatments over time. Patients and Methods: English-speaking patients were randomized (3:1) to T-DM1 or TH, and completed PRO assessments at baseline (day 1), 3 wks, 12 wks, and 6, 12, and 18 mos after initiation of treatment. Surveys included the FACT-B, Patient-Neurotoxicity Questionnaire (PNQ), Rotterdam Symptom Checklist (RSCL), Alopecia Patient Assessment, and Work Productivity and Activity Impairment Questionnaire: Specific Health Problem (WPAI:SHP). Results: 469/497 (94%) patients (363 on T-DM1, 106 on TH) completed surveys at any timepoint, ranging from 100% at baseline to 79% at 18 mos. Median age was 56 yrs (range 23-85). There were different patterns of deterioration and recovery seen over time in each group for QOL and other relevant symptoms. Compared with the T-DM1 group, the TH group had significantly lower mean total FACT-B scores, indicating poorer QOL from baseline to 12 weeks (p&lt;0.001 for each timepoint); mean scores were similar between the groups at 6 and 12 mos, and significantly worse again in the TH group at 18 mos. The greatest mean change from baseline, and lowest FACT-B scores overall were reported in the TH group at 12 weeks. Moderate to severe sensory neuropathy was 8% at 12 weeks for patients receiving T-DM1 and reached its highest level of 15% by 18 mos. In comparison, moderate to severe sensory neuropathy was 35% at 12 weeks and 26% at 18 mos for patients on TH (p&lt;0.001 at 12 weeks and p=0.018 at 18 mos). Hair loss at week 12 was 13% on T-DM1 compared to 77% on TH (p&lt;0.001). Mean physical symptom distress was greater for TH at baseline, 3 and 12 weeks, and greater for T-DM1 at 1 year, with greatest symptom distress reported by the TH group at 12 weeks. Psychological distress was greatest for both groups at enrollment, though significantly greater with TH than T-DM1 at baseline, 12 weeks and 18 mos (groups were similar at 6 and 12 mos). There was limited impact on activity level impairment in both groups. Rates of employment were lowest for the TH group at 12 weeks (49% TH vs. 61% T-DM1, p=0.074) with significant differences seen at 3 and 12 weeks for percent work time missed due to health treatment, percent impairment while working, percent overall work impairment, and percent activity impairment, all favoring T-DM1. Conclusion: PROs differ between patients with Stage I HER2 positive breast cancer treated with T-DM1 vs. TH. T-DM1 treated patients had better QOL, less neuropathy and hair loss, and better work productivity, particularly during the first 12 weeks of treatment, and importantly, differences persist with longer-term follow-up.

Citation Format: Ann Partridge, Yue Zheng, Shoshana Rosenberg, Richard Gelber, Shari Gelber, William Barry, Chau Dang, Denise Yardley, Steven Isakoff, Vicente Valero, Meredith Faggen, Therese Mulvey, Ron Bose, Douglas Weckstein, Antonio Wolff, Katherine Reeder-Hayes, Hope Rugo, Bhuvaneswari Ramaswamy, Dan Zuckerman, Lowell Hart, Vijayakrishna Gadi, Michael Constantine, Kit Cheng, Frederick Briccetti, Bryan Schneider, Merrill Garrett, P. Kelly Marcom, Kathy Albain, Patricia Defusco, Nadine Tung, Blair Ardman, Rita Nanda, Rachel Jankowitz, Michelle DeMeo, Harold Burstein, Eric P. Winer, Ian Krop, Sara Tolaney. Patient reported outcomes from the adjuvant trastuzumab emtansine (T-DM1) vs. paclitaxel + trastuzumab (TH) (ATEMPT) trial (TBCRC 033) [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 PD10-02.

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

BACKGROUND

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT00542451.

Abstract P1-15-01: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Metzger Filho O, Janiszewska M, Guo H, Yardley D, Mayer I, Spring L, Arteaga C, Wrabel E, DeMeo M, Freedman R, Tolaney S, Waks A, Bardia A, Parsons H, Partridge A, Mayer E, King T, Polyak K, Viale G, Winer E, Krop I. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-15-01.

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 P1-17-03: Abemaciclib for the treatment of brain metastases secondary to hormone receptor positive breast cancer

Background: Although a lower percentage of patients with hormone receptor-positive (HR+) metastatic breast cancer (MBC) develop brain metastases when compared with triple negative and HER2+ MBC patients, there are no regulatory approved systemic agents for the treatment of HR+ breast cancer brain metasteses, and this remains an unmet medical need. Standard local treatment options include surgery, stereotactic radiosurgery (SRS), and/or whole brain radiation therapy (WBRT). Abemaciclib, an oral selective CDK4 and 6 inhibitor administered on a continuous dosing schedule, has demonstrated clinical activity and an acceptable safety profile in heavily pre-treated HR+ MBC patients. Preclinically, abemaciclib crosses the blood-brain barrier, which is further supported clinically by detectable levels of abemaciclib similar to plasma levels in resected brain metastases in a subset of patients with HR+, HER2- MBC as previously reported for the current study. Together these data provide further rationale for evaluating abemaciclib in patients with brain metastases.

Methods: Study I3Y-MC-JPBO (NCT02308020) is an open-label, Phase 2, Simon 2-Stage trial evaluating the safety and efficacy of abemaciclib up to 200 mg BID in 4 cohorts of patients with brain metastases secondary to HR+ MBC, NSCLC, or melanoma. With regard to HR+ MBC, one cohort included HR+, HER2- patients, another one included HR+/HER2+ patients. All HR+ MBC patients enrolled to 1 of these 2 cohorts were required to have at least 1 measurable brain lesion. The primary objective was objective intracranial response rate as defined by Response Assessment in Neuro-Oncology brain metastases response criteria. Stage 1 was to enroll 23 evaluable patients per study part; if ≥2 respond to abemaciclib, 33 additional evaluable patients were to be enrolled to Stage 2. Secondary CNS objectives include best overall response, duration of response, and clinical benefit rate.

Results: For Stage 1 efficacy, in patients with HR+, HER2+ MBC futility was met. However, for HR+, HER2- patients, 2 confirmed, durable partial responses were observed and enrollment to Stage 2 is ongoing.

Conclusions: Previously, this study provided evidence that abemaciclib penetrates brain metastases in patients with HR+, HER2- MBC. The current results provide sufficient evidence of anti-tumor activity on brain metastases in patients with HR+, HER2- MBC to merit further exploration, but not for patients with HR+, HER2+ disease. Safety and tolerability results are similar to those previously reported for abemaciclib, with the majority of adverse events being gastrointestinal.

Citation Format: Bachelot T, Kabos P, Yardley D, Dieras V, Costigan T, Klise S, Awada A. Abemaciclib for the treatment of brain metastases secondary to hormone receptor positive breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-17-03.

Abstract CT110: Ribociclib in combination with everolimus and exemestane in men and postmenopausal women with HR+/HER2− advanced breast cancer following progression on a CDK4/6 inhibitor: Safety, tolerability, and pharmacokinetic results from Phase 1 of TRINITI-1 study

Introduction: Preclinical data of improved antitumor activity upon addition of ribociclib to everolimus (EVE) and the interplay of CDK4/6 and the PI3K/mTOR pathway suggest a potential use for combination therapy to restore sensitivity to both CDK4/6 inhibition and endocrine therapy in patients whose disease progresses with CDK4/6 inhibitors. We present Phase 1 data of ribociclib (dosed continuously) + EVE + exemestane (EXE) in patients with endocrine-resistant ABC. Methods: TRINITI-1 is a Phase 1/2, open-label study of ribociclib (250 mg/d or 300 mg/d) + EVE 2.5 mg/d + EXE 25 mg/d in men and postmenopausal women with hormone receptor-positive, HER2− ABC who had progressed on 1 to 3 lines of systemic endocrine therapy, had measurable disease and/or lytic/mixed bone lesions, and had an Eastern Cooperative Oncology Group performance status score of ≤1 (NCT02732119). Progression on a CDK4/6 inhibitor was required only for patients in Phase 2. Patients with visceral crisis, unstable CNS metastases, progression after treatment with &gt;1 CDK4/6 inhibitor, or clinically significant heart disease were excluded. The primary objective of Phase 1 was identification of the maximum tolerated dose (MTD) and/or the recommended Phase 2 dose (RP2D) of ribociclib + EVE + EXE. Secondary objectives included safety, tolerability, and pharmacokinetic analyses. Results: Among the 17 patients evaluated, 0 and 1 (11%) DLTs were noted in the ribociclib 250 mg/d and 300 mg/d cohorts, respectively (Grade 3 febrile neutropenia and Grade 4 neutropenia). Thus, MTD was not reached, and ribociclib 300 mg/d + EVE 2.5 mg/d + EXE 25 mg/d was declared the RP2D. Grade 3/4 drug-related AEs occurred in 75% of patients in each cohort; Grade 3/4 AEs (in &gt;20% of patients) included neutropenia (25% and 50% in 250 mg and 300 mg cohorts, respectively) and decreased neutrophil count (38% and 0%). No increases in liver function tests or QTcF occurred. Median steady-state trough concentrations (Ctrough) of ribociclib at cycle 1, day 15, were 160 ng/mL and 210 ng/mL in the 250 mg/d and 300 mg/d cohorts, respectively, consistent with single-agent ribociclib 280 mg (164 ng/mL). However, median steady-state EVE Ctrough levels when combined with 250 mg and 300 mg ribociclib were within the therapeutic target of 5-15 ng/mL (7.8 ng/mL and 9.4 ng/mL, respectively) and were 2- to 3-fold greater than expected based on single-agent data.Conclusions: Ribociclib at 250 mg/d or 300 mg/d + EVE 2.5 mg/d + EXE 25 mg/d dosed continuously was safe in patients with HER2-, HR+ ABC. Ribociclib 300 mg/d was chosen for the RP2D and is being studied in Phase 2. Ribociclib Ctrough was similar to expected values, whereas EVE Ctrough was 2- to 3-fold greater than expected, resulting in EVE exposure within the therapeutic range despite the low EVE dose.

Citation Format: Sara Hurvitz, Denise Yardley, Amelia Zelnak, Angela DeMichele, Elizabeth Tan-Chiu, Cynthia Ma, Tania Small, Chris Tucci, Tanay Samant, Das Purkayastha, Stacy Moulder, Aditya Bardia. Ribociclib in combination with everolimus and exemestane in men and postmenopausal women with HR+/HER2− advanced breast cancer following progression on a CDK4/6 inhibitor: Safety, tolerability, and pharmacokinetic results from Phase 1 of TRINITI-1 study [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 CT110. doi:10.1158/1538-7445.AM2017-CT110

Abstract P4-22-13: Everolimus plus trastuzumab and paclitaxel as first-line therapy in women with HER2+ advanced breast cancer: Overall survival results from BOLERO-1

Background

Everolimus (EVE), an mTOR inhibitor has shown activity in HER2+ advanced breast cancer (ABC) in both preclinical and clinical studies. In the pivotal BOLERO-1 trial (NCT00876395), the progression-free survival (PFS) was not significantly different between the EVE + trastuzumab (TRAS) + paclitaxel (PAC) combination and placebo (PBO) + TRAS + PAC in the full HER2+ population (EVE, 15.0 mo vs PBO, 14.5 mo; HR=0.89; 95% CI: 0.73-1.08; p=0.1166). Although not reaching protocol defined level for statistical significance, the hormone receptor negative (HR-) subpopulation appeared to benefit from EVE, with a 7.2 mo PFS benefit vs PBO arm (EVE, 20.3 mo vs PBO, 13.1 mo; HR=0.66; 95% CI: 0.48-0.91; p=0.0049). The final exploratory overall survival (OS) analysis from the study is presented here.

Methods

In this phase 3 randomized trial, 719 women with HER2+ ABC without prior TRAS or chemotherapy in the metastatic setting were randomized 2:1 to receive either EVE (10 mg/d) or placebo (PBO) and weekly PAC+TRAS, stratified by visceral metastasis (lung, liver, peritoneal or pleural: yes vs no) and prior adjuvant or neo-adjuvant treatment with TRAS (yes vs no). As the primary objectives (PFS on full population and on HR- subpopulation) of BOLERO-1 were not met, the key secondary endpoint of OS was not formally statistically tested. However, given the results of PFS, in particular in the HR- subpopulation, a change to the OS analysis plan was made by introducing one final exploratory OS analysis at the time of study termination.

Results

At data cutoff (Dec 31, 2015), the median duration of exposure was 40.8 weeks (range: 0.6-320.4) in the EVE arm and 48.1 weeks (range: 1.1-308.0) in the PBO arm. After a median follow-up of 60.3 mo, 350 deaths were recorded in the full population, 238 (49.6%) in the EVE arm and 112 (46.9%) pts in the PBO arm. In the full population, the median OS was comparable in the EVE vs PBO arms (48.6 mo vs 50.0 mo respectively; HR = 1.13; 95% CI: 0.90-1.42). In the HR- subpopulation, 138 deaths were recorded; 88 (42.3%) pts in the EVE arm and 50 (48.5%) pts in the PBO arm. In the HR- subpopulation, the median OS in the EVE arm was longer compared to PBO arm (57.0 mo vs 41.6 mo respectively; HR = 0.83; 95% CI: 0.59-1.18). Stomatitis, diarrhea, alopecia, cough, rash, pyrexia, neutropenia, and fatigue were the most frequent adverse events (AEs) reported in EVE arm (≥35%). AEs leading to dose interruption and/or change were reported in 441 (93.4%) pts in EVE arm and 165 (69.3%) pts in the PBO arm respectively. Overall, AEs leading to treatment discontinuation were reported in 262 (55.5%) pts in EVE arm and 98 (41.2%) pts in PBO arm. Serious AEs were reported in 171 (36.2%) pts in the EVE arm and 40 (16.8%) pts in the PBO arm respectively. On treatment AE related deaths were reported for 3.6% pts in the EVE arm and 0% pts in the PBO arm.

Conclusions

The median OS was similar in the EVE vs PBO arms for overall population. However, a prolongation of 15.4 mo in median OS of HR- subpopulation was observed in the EVE arm vs PBO arm in this exploratory analysis. Pts in the EVE arm had a manageable safety, consistent with the safety profile of EVE and no new safety signals were identified.

Citation Format: Yardley D, Hurvitz S, Jiang Z-f, Toi M, Burris H, Buyse M, Slamon D, Makhson A, Elsaid A, Lerzo G, Hellerstedt B, Nuzzo F, Sohn J, Manzyuk L, Cabaribere D, Lincy J, Weimann A, Noel-Baron F, Pacaud L, Andre F. Everolimus plus trastuzumab and paclitaxel as first-line therapy in women with HER2+ advanced breast cancer: Overall survival results from BOLERO-1 [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-22-13.

Comparative Efficacy and Safety of Adjuvant Letrozole Versus Anastrozole in Postmenopausal Patients With Hormone Receptor-Positive, Node-Positive Early Breast Cancer: Final Results of the Randomized Phase III Femara Versus Anastrozole Clinical Evaluation (FACE) Trial

Purpose The Letrozole (Femara) Versus Anastrozole Clinical Evaluation (FACE) study compared the efficacy and safety of adjuvant letrozole versus anastrozole in postmenopausal patients with hormone receptor (HR) -positive and node-positive early breast cancer (eBC). Methods Postmenopausal women with HR-positive and node-positive eBC were randomly assigned to receive adjuvant therapy with either letrozole (2.5 mg) or anastrozole (1 mg) once per day for 5 years or until recurrence of disease. Patients were stratified on the basis of the number of lymph nodes and human epidermal growth factor receptor 2 status. The primary end point was 5-year disease-free survival (DFS), and the key secondary end points were overall survival and safety. Results A total of 4,136 patients were randomly assigned to receive either letrozole (n = 2,061) or anastrozole (n = 2,075). The final analysis was done at 709 DFS events (letrozole, 341 [16.5%]; anastrozole, 368 [17.7%]). The 5-year estimated DFS rate was 84.9% for letrozole versus 82.9% for anastrozole arm (hazard ratio, 0.93; 95% CI, 0.80 to 1.07; P = .3150). Exploratory analysis showed similar DFS with letrozole and anastrozole in all evaluated subgroups. The 5-year estimated overall survival rate was 89.9% for letrozole versus 89.2% for anastrozole arm (hazard ratio, 0.98; 95% CI, 0.82 to 1.17; P = .7916). Most common grade 3 to 4 adverse events (> 5% of patients) reported for letrozole versus anastrozole were arthralgia (3.9% v 3.3%, and 48.2% v 47.9% for all adverse events), hypertension (1.2% v 1.0%), hot flushes (0.8% v 0.4%), myalgia (0.8% v 0.7%), dyspnea (0.8% v 0.5%), and depression (0.8% v 0.6%). Conclusion Letrozole did not demonstrate significantly superior efficacy or safety compared with anastrozole in postmenopausal patients with HR-positive, node-positive eBC.

Ribociclib as First-Line Therapy for HR-Positive, Advanced Breast Cancer

BACKGROUND

The inhibition of cyclin-dependent kinases 4 and 6 (CDK4/6) could potentially overcome or delay resistance to endocrine therapy in advanced breast cancer that is positive for hormone receptor (HR) and negative for human epidermal growth factor receptor 2 (HER2).

METHODS

In this randomized, placebo-controlled, phase 3 trial, we evaluated the efficacy and safety of the selective CDK4/6 inhibitor ribociclib combined with letrozole for first-line treatment in 668 postmenopausal women with HR-positive, HER2-negative recurrent or metastatic breast cancer who had not received previous systemic therapy for advanced disease. We randomly assigned the patients to receive either ribociclib (600 mg per day on a 3-weeks-on, 1-week-off schedule) plus letrozole (2.5 mg per day) or placebo plus letrozole. The primary end point was investigator-assessed progression-free survival. Secondary end points included overall survival, overall response rate, and safety. A preplanned interim analysis was performed on January 29, 2016, after 243 patients had disease progression or died. Prespecified criteria for superiority required a hazard ratio of 0.56 or less with P<1.29×10^-5.

RESULTS

The duration of progression-free survival was significantly longer in the ribociclib group than in the placebo group (hazard ratio, 0.56; 95% CI, 0.43 to 0.72; P=3.29×10^-6 for superiority). The median duration of follow-up was 15.3 months. After 18 months, the progression-free survival rate was 63.0% (95% confidence interval [CI], 54.6 to 70.3) in the ribociclib group and 42.2% (95% CI, 34.8 to 49.5) in the placebo group. In patients with measurable disease at baseline, the overall response rate was 52.7% and 37.1%, respectively (P<0.001). Common grade 3 or 4 adverse events that were reported in more than 10% of the patients in either group were neutropenia (59.3% in the ribociclib group vs. 0.9% in the placebo group) and leukopenia (21.0% vs. 0.6%); the rates of discontinuation because of adverse events were 7.5% and 2.1%, respectively.

CONCLUSIONS

Among patients receiving initial systemic treatment for HR-positive, HER2-negative advanced breast cancer, the duration of progression-free survival was significantly longer among those receiving ribociclib plus letrozole than among those receiving placebo plus letrozole, with a higher rate of myelosuppression in the ribociclib group. (Funded by Novartis Pharmaceuticals; ClinicalTrials.gov number, NCT01958021 .).

Cardiac Outcomes of Patients Receiving Adjuvant Weekly Paclitaxel and Trastuzumab for Node-Negative, ERBB2-Positive Breast Cancer

IMPORTANCE

Trastuzumab is a life-saving therapy but is associated with symptomatic and asymptomatic left ventricular ejection fraction (LVEF) decline. We report the cardiac toxic effects of a nonanthracycline and trastuzumab-based treatment for patients with early-stage human epidermal growth factor receptor 2 (ERBB2, formerly HER2 or HER2/neu)-positive breast cancer.

OBJECTIVE

To determine the cardiac safety of paclitaxel with trastuzumab and the utility of LVEF monitoring in patients with node-negative, ERBB2-positive breast cancer.

DESIGN, SETTING, AND PARTICIPANTS

In this secondary analysis of an uncontrolled, single group study across 14 medical centers, enrollment of 406 patients with node-negative, ERBB2-positive breast cancer 3 cm, or smaller, and baseline LVEF of greater than or equal to 50% occurred from October 9, 2007, to September 3, 2010. Patients with a micrometastasis in a lymph node were later allowed with a study amendment. Median patient age was 55 years, 118 (29%) had hypertension, and 30 (7%) had diabetes. Patients received adjuvant paclitaxel for 12 weeks with trastuzumab, and trastuzumab was continued for 1 year. Median follow-up was 4 years.

INTERVENTIONS

Treatment consisted of weekly 80-mg/m2 doses of paclitaxel administered concurrently with trastuzumab intravenously for 12 weeks, followed by trastuzumab monotherapy for 39 weeks. During the monotherapy phase, trastuzumab could be administered weekly 2-mg/kg or every 3 weeks as 6-mg/kg. Radiation and hormone therapy were administered per standard guidelines after completion of the 12 weeks of chemotherapy. Patient LVEF was assessed at baseline, 12 weeks, 6 months, and 1 year.

MAIN OUTCOMES AND MEASURES

Cardiac safety data, including grade 3 to 4 left ventricular systolic dysfunction (LVSD) and significant asymptomatic LVEF decline, as defined by our study, were reported.

RESULTS

Overall, 2 patients (0.5%) (95% CI, 0.1%-1.8%) developed grade 3 LVSD and came off study, and 13 (3.2%) (95% CI, 1.9%-5.4%) had significant asymptomatic LVEF decline, 11 of whom completed study treatment. Median LVEF at baseline was 65%; 12 weeks, 64%; 6 months, 64%; and 1 year, 64%.

CONCLUSIONS AND RELEVANCE

Cardiac toxic effects from paclitaxel with trastuzumab, manifesting as grade 3 or 4 LVSD or asymptomatic LVEF decline, were low. Patient LVEF was assessed at baseline, 12 weeks, 6 months, and 1 year, and our findings suggest that LVEF monitoring during trastuzumab therapy without anthracyclines could be simplified for many individuals.

Safety of long-term denosumab therapy: results from the open label extension phase of two phase 3 studies in patients with metastatic breast and prostate cancer

Purpose

Zoledronic acid (ZA) or denosumab treatment reduces skeletal-related events; however, the safety of prolonged therapy has not been adequately studied. Here, we describe safety results of extended denosumab therapy in patients with bone metastases from the open-label extension phase of two phase 3 trials.

Methods

Patients with metastatic breast or prostate cancer received subcutaneous denosumab 120 mg Q4W or intravenous ZA 4 mg Q4W in a double-blinded fashion. Denosumab demonstrated superior efficacy in the blinded treatment phase; thus, patients were offered open-label denosumab for up to an additional 2 years.

Results

Cumulative median (Q1, Q3) denosumab exposure was 19.1 (9.2, 32.2) months in the breast cancer trial (n = 1019) and 12.0 (5.6, 21.3) months in the prostate cancer trial (n = 942); 295 patients received denosumab for >3 years. No new safety signals were identified during the open-label phase, or among patients who switched from ZA to denosumab. During the blinded treatment phase, exposure-adjusted subject incidences of osteonecrosis of the jaw (ONJ) were 49 (1.9 %) and 31 (1.2 %) in the denosumab and ZA groups, respectively. In total, 32 (6.9 %) and 25 (5.5 %) new cases of ONJ (not adjusted for exposure) were reported for patients continuing and switching to denosumab, respectively. The incidences of hypocalcemia were 4.3 and 3.1 %, in patients continuing and switching to denosumab, respectively.

Conclusion

These results describe the safety profile of denosumab after long-term exposure, or after switching to denosumab from ZA. No new safety signals were identified. Hypocalcemia rates were similar in the blinded treatment and open-label phases. ONJ rates increased with increasing exposure to antiresorptives, consistent with previous reports.

Abstract S2-02: The FERGI phase II study of the PI3K inhibitor pictilisib (GDC-0941) plus fulvestrant vs fulvestrant plus placebo in patients with ER+, aromatase inhibitor (AI)-resistant advanced or metastatic breast cancer – Part I results

Background: Preclinical and clinical data indicate a key role for the PI3-kinase (PI3K) pathway in the pathogenesis of resistance to endocrine therapies in hormone receptor-positive (HR) breast cancer (BC) and suggest that combining PI3K inhibitors with endocrine therapy may partially overcome this resistance. FERGI is the first randomized Phase II study testing pictilisib (GDC-0941), a PI3K inhibitor, in combination with fulvestrant to evaluate this hypothesis in MBC patients with and without PIK3CA-mutant tumors.

Methods: 168 post-menopausal pts with ER-positive, HER2-negative MBC were randomized (1:1) to receive fulvestrant with either pictilisib 340 mg QD (n=89, "combination" arm) or matching placebo (n=79, "control" arm). To be eligible, pts had to have relapsed during or within 6 mos of completing adjuvant AI treatment or have progressed on an AI for MBC. Pts were stratified based on tumor PIK3CA mutation status, resistance to prior AI therapy and presence of measurable disease. The primary endpoint was PFS by investigator assessment in the intent-to-treat (ITT) group and in pts with centrally confirmed PIK3CA-mutant tumors. The primary analysis was based on a 6 mo median duration follow up.

Results: Baseline disease and prior treatment characteristics were similar between study arms. Observed treatment-emergent AEs were consistent with those previously described for single agent pictilisib and fulvestrant (primary toxicities were rash and GI disorders). In the ITT population (84 events) the median PFS (mPFS) was 6.2 mo in the combination arm vs 3.8 months for the control arm (HR, 0.77; 95% CI, 0.50-1.19). For pts with PIK3CA-mutant tumors (37 events), mPFS was 6.2 mo in the combination arm vs 5.1 mo in the control arm (HR, 0.92; 95% CI, 0.48-1.76). For pts without a detectable PIK3CA mutant tumor (43 events), mPFS was 5.8 months in the combination arm vs 3.6 months in the control arm (HR, 0.64; 95% CI, 0.35-1.17). Exploratory post-hoc subgroup analysis suggested improvement in PFS in pts with ER+ and PR+ tumors (centrally confirmed) treated with pictilisib plus fulvestrant. In the ER+/PR+ subgroup (57 events) mPFS was 7.2 mo in the combination arm vs 3.7 mo in the control arm (HR, 0.46; 95% CI, 0.27 to 0.78). This improvement was independent of tumor PIK3CA mutation status. Multivariate analysis suggests that this treatment effect in pts with ER+/PR+ tumors is maintained after adjusting for possible baseline imbalances. A similar analysis on pts with luminal A tumors (per PAM50 analysis) was also consistent with the findings in pts ER+/PR+ disease.

Conclusions: This is the first report of a blinded, randomized clinical study evaluating a PI3K inhibitor in pts with MBC. In the ITT population, the addition of pictilisib to fulvestrant was associated with a mPFS improvement of 3.8 mo to 6.2 mo. Exploratory subgroup analyses suggested in pts with ER+/PR+ tumors are more likely to derive benefit from the addition of pictilisib to fulvestrant irrespective of PIK3CA mutation status, though the subgroup analyses are limited by the sample size. Additional biomarker analyses will be reported.

Citation Format: Ian Krop, Stephen Johnston, Ingrid A Mayer, Maura Dickler, Vinod Ganju, Andres Forero-Torres, Bohuslav Melichar, Serafin Morales, Richard de Boer, Steven Gendreau, Mika Derynck, Mark Lackner, Jill Spoerke, Ru-Fang Yeh, Gallia Levy, Vivian Ng, Carol O'Brien, Heidi Savage, Yuanyuan Xiao, Timothy Wilson, Soo Chin Lee, Katarina Petrakova, Susanne Vallentin, Denise Yardley, Matthew Ellis, Martine Piccart, Edith A Perez, Eric Winer, Peter Schmid. The FERGI phase II study of the PI3K inhibitor pictilisib (GDC-0941) plus fulvestrant vs fulvestrant plus placebo in patients with ER+, aromatase inhibitor (AI)-resistant advanced or metastatic breast cancer – Part I results [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr S2-02.

First-line treatment patterns and clinical outcomes in patients with HER2-positive and hormone receptor-positive metastatic breast cancer from registHER

BACKGROUND

Limited data are available describing the natural history of patients with HER2-positive and hormone receptor (HR)-positive metastatic breast cancer (MBC). We examined first-line treatment patterns and clinical outcomes in patients with HER2-positive, HR-positive MBC in a real-world setting.

METHODS

registHER is a prospective, observational cohort of 1,023 patients with HER2-positive MBC diagnosed within 6 months of enrollment and followed until death, disenrollment, or June 2009 (median follow-up time: 27 months). Demographics, first-line treatment patterns, and clinical outcomes were examined for 530 HER2-positive, HR-positive patients. Progression-free survival (PFS) and overall survival (OS) times were examined. Multivariate analyses adjusted for baseline demographic and prognostic factors.

RESULTS

HER2-positive, HR-positive patients receiving first-line trastuzumab plus hormonal therapy had significantly longer PFS times than patients who received hormonal therapy only (13.8 vs. 4.8 months; adjusted hazard ratio [HR]: 0.37, 95% confidence interval [CI]: 0.22-0.60); a nonsignificant reduction in OS time was observed (adjusted HR: 0.55, 95% CI: 0.27-1.14). Compared with patients who received first-line trastuzumab plus chemotherapy, patients who received first-line trastuzumab plus chemotherapy and hormonal therapy had longer median PFS times (20.4 months vs. 9.5 months; adjusted HR: 0.53, 95% CI: 0.42-0.68); a statistically significant reduction in risk of death was observed (adjusted HR: 0.50, 95% CI: 0.36-0.70). Sequential use of chemotherapy and hormonal therapy was associated with improved OS times when compared with concurrent use (adjusted PFS HR: 0.81, 95% CI: 0.54-1.21; adjusted OS HR: 0.48, 95% CI: 0.26-0.89).

CONCLUSIONS

These real-world data in patients with HER2-positive/HR-positive MBC provide evidence that, with or without chemotherapy, dual targeting of HRs and HER2 receptors is associated with significantly prolonged PFS and OS times.

Abstract 2397: Correlation between biomarker status and response to EGFR inhibition in triple-negative breast cancer (TNBC): findings from a Phase II trial

Background: Epidermal growth factor receptor (EGFR) inhibition in TNBC has shown promising response in some studies, however, these studies have not investigated the correlation between response to EGFR inhibition and EGFR-related biomarker status. In this study, EGFR-related biomarkers in TNBC including p53 expression, EGFR gene amplification, and signalling pathways including RAS and PI3K were investigated to explore potential biomarkers that may correlate with response to EGFR inhibition.

Methods: A total of 71 locally advanced or metastatic TNBC patients with no prior EGFR inhibitor treatment and 0 - 1 prior chemotherapy regimens for metastatic breast cancer were evaluated. All patients received gemcitabine 1500mg/m2 IV, carboplatin AUC = 2.5 IV, and panitumumab 6 mg/kg IV every 2 weeks. Archival tumor tissue was obtained from 68 patients for central biomarker analyses. Protein expression of PTEN and p53 in tumor samples was assessed by Immunohistochemistry (IHC). Fluorescence-in-situ-hybridization (FISH) was used to detect EGFR gene amplification. KRAS (codons 12 and 13 in exon 2) and PI3KCA (exons 9 and 20) mutations were analyzed by direct DNA sequencing using capillary gel electrophoresis and fluorescence detection. Bioinformatics analyses were performed to correlate the status of these biomarkers with objective response rate (ORR), progression free survival (PFS) and overall survival (OS).

Results: 27 patients had partial response (PR), median PFS was 4.30 months and median OS was 12.58 months. 12/68 (18%) tumors had EGFR amplification. No KRAS mutations were detected in the 62 samples tested (6 patients not evaluable). 18% of tumors demonstrated PI3KCA mutations (12/67). 5/67 (7%) samples had PTEN loss. 50% of the tumors exhibited p53 loss (34/68). 13/68 (19%) tumors had more than one biomarker alteration. PTEN loss and PI3KCA mutation were mutually exclusive in the 67 tumors evaluated. In univariate analyses, none of these biomarkers significantly correlated with ORR, PFS or OS (all, P&gt;0.05). There was a marginal trend to shorter PFS (P=0.08) with PTEN loss and a marginal trend to longer PFS (P=0.106) with p53 loss. In multivariate analyses, none of the four biomarkers (EGFR, PI3KCA, PTEN and p53) showed prognostic significance on OS (all, P&gt;0.05).

Conclusions: We hypothesize that constitutive activation of the PI3K pathway due to PTEN loss and activation of EGFR by p53 loss may be potential mechanisms for the observed responses to panitumumab. This single arm study suggests that EGFR gene amplification may not be a predictor for response to panitumumab in TNBC. Further investigation in a randomized trial with a more homogenous patient population is warranted to confirm these findings.

Citation Format: Denise Yardley, Denise Yardley, Zeqiang Ma, Patrick Ward, Carolyn Hendricks, Brooke Daniel, William Harwin, George J. Kannarkat, Mythili Shastry, Nancy Peacock, Shile Liang. Correlation between biomarker status and response to EGFR inhibition in triple-negative breast cancer (TNBC): findings from a Phase II trial. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2397. doi:10.1158/1538-7445.AM2013-2397

A phase II study of trastuzumab emtansine in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer who were previously treated with trastuzumab, lapatinib, an anthracycline, a taxane, and capecitabine

PURPOSE

To determine whether the antibody-drug conjugate trastuzumab emtansine (T-DM1), which combines human epidermal growth factor receptor 2 (HER2) -targeted delivery of the potent antimicrotubule agent DM1 with the antitumor activity of trastuzumab, is effective in patients with HER2-positive metastatic breast cancer (MBC) who have previously received all standard HER2-directed therapies.

PATIENTS AND METHODS

In this single-arm phase II study, T-DM1 3.6 mg/kg was administered intravenously every 3 weeks to patients with HER2-positive MBC who had prior treatment with trastuzumab, lapatinib, an anthracycline, a taxane, and capecitabine. The primary objectives were overall response rate (ORR) by independent review and safety.

RESULTS

Among 110 pretreated patients (median, seven prior agents for MBC; median follow-up, 17.4 months), the ORR was 34.5% (95% CI, 26.1% to 43.9%), clinical benefit rate was 48.2% (95% CI, 38.8% to 57.9%), median progression-free survival (PFS) was 6.9 months (95% CI, 4.2 to 8.4 months), and median duration of response was 7.2 months (95% CI, 4.6 months to not estimable). In patients with confirmed HER2-positive tumors (n = 80 by retrospective central testing), the response rate was 41.3% (95% CI, 30.4% to 52.8%), and median PFS was 7.3 months (95% CI, 4.6 to 12.3 months). Most adverse events were grades 1 to 2; the most frequent grade ≥ 3 events were thrombocytopenia (9.1%), fatigue (4.5%), and cellulitis (3.6%).

CONCLUSION

T-DM1 is well tolerated and has single-agent activity in patients with HER2-positive MBC who have previously received both approved HER2-directed therapies and multiple chemotherapy agents. T-DM1 may be an effective new treatment for this patient population.

Everolimus in postmenopausal hormone-receptor-positive advanced breast cancer

BACKGROUND

Resistance to endocrine therapy in breast cancer is associated with activation of the mammalian target of rapamycin (mTOR) intracellular signaling pathway. In early studies, the mTOR inhibitor everolimus added to endocrine therapy showed antitumor activity.

METHODS

In this phase 3, randomized trial, we compared everolimus and exemestane versus exemestane and placebo (randomly assigned in a 2:1 ratio) in 724 patients with hormone-receptor-positive advanced breast cancer who had recurrence or progression while receiving previous therapy with a nonsteroidal aromatase inhibitor in the adjuvant setting or to treat advanced disease (or both). The primary end point was progression-free survival. Secondary end points included survival, response rate, and safety. A preplanned interim analysis was performed by an independent data and safety monitoring committee after 359 progression-free survival events were observed.

RESULTS

Baseline characteristics were well balanced between the two study groups. The median age was 62 years, 56% had visceral involvement, and 84% had hormone-sensitive disease. Previous therapy included letrozole or anastrozole (100%), tamoxifen (48%), fulvestrant (16%), and chemotherapy (68%). The most common grade 3 or 4 adverse events were stomatitis (8% in the everolimus-plus-exemestane group vs. 1% in the placebo-plus-exemestane group), anemia (6% vs. <1%), dyspnea (4% vs. 1%), hyperglycemia (4% vs. <1%), fatigue (4% vs. 1%), and pneumonitis (3% vs. 0%). At the interim analysis, median progression-free survival was 6.9 months with everolimus plus exemestane and 2.8 months with placebo plus exemestane, according to assessments by local investigators (hazard ratio for progression or death, 0.43; 95% confidence interval [CI], 0.35 to 0.54; P<0.001). Median progression-free survival was 10.6 months and 4.1 months, respectively, according to central assessment (hazard ratio, 0.36; 95% CI, 0.27 to 0.47; P<0.001).

CONCLUSIONS

Everolimus combined with an aromatase inhibitor improved progression-free survival in patients with hormone-receptor-positive advanced breast cancer previously treated with nonsteroidal aromatase inhibitors. (Funded by Novartis; BOLERO-2 ClinicalTrials.gov number, NCT00863655.).

P1-18-01: Z-ACT1: Zometa Combined with Standard Therapy in Patients with Metastatic Breast Cancer Further Decreases the Proportion of Patients with CTC Counts of 5 or above

Introduction: Zoledronic acid (ZOL) has been shown to reduce the risk of recurrence and residual tumor size in the adjuvant/neoadjuvant setting in patients with early/intermediate-stage breast cancer (BC). In addition, ZOL combined with neoadjuvant chemotherapy reduced numbers of disseminated-tumor cells in the bone marrow compared with chemotherapy alone. However, the activity of ZOL on disseminated- or circulating-tumor cells (CTCs) in patients with metastatic breast cancer (MBC) is not well defined. Cristofanilli M, et al (J Clin Oncol. 2005; 23: 1420–30) reported that CTCs in MBC are an independent predictor of overall survival (OS) and progressionfree survival (PFS). Accordingly, this study is evaluating the potential anticancer benefit of adding ZOL to standard therapy in patients with newly diagnosed MBC as assessed by the change in CTC count from baseline to 3–5 weeks.

Methods: Eligible patients had HER2−negative MBC, newly diagnosed or at first relapse after adjuvant therapy with or without bone metastases. In this open-label 3-arm study, patients without bone metastases were randomized to standard therapy + ZOL every 3–4 weeks for the first 6 months (Arm A) or standard therapy + ZOL during month 6–12 after standard therapy initiation (Arm B). All patients with bone metastases received ZOL every 3–4 weeks (Arm C). The primary endpoint is PFS. Secondary endpoints include the proportion of patients with CTCs ≥5 or &lt;5 per 7.5 mL of peripheral blood 3–5 weeks after standard therapy initiation. Data were compared with historical controls (patients with MBC receiving first-line standard treatment alone; Cristofanilli M, et al. 2005). CTCs were quantified using CellSearch™.

Results: In Z-ACT1, 29 previously untreated MBC patients with bone metastases were enrolled in Arm C, all of whom had ≥1 CTC at study entry (range, 1–117). 53% received hormonal therapy alone, 42% chemotherapy alone, and 5% received various combinations. In patients receiving standard therapy + ZOL, the percentage of patients with CTC ≥5 decreased from 55% to 25% at 3–5 weeks. At baseline, the median uNTX level was 46.5 (n = 10) in patients with &lt; 5 CTCs and 57 in patients with ≥5 CTC (n = 13). At 3–5 weeks, the median decrease from baseline in uNTX was 74% (n = 10) in the &lt; 5 CTC group and 25% (n = 5) in the ≥5 CTC group. At 3–5 weeks, the median uNTX levels in the &lt;5 and ≥5 CTC groups were 12 and 22 nmol bce/mmol, respectively. This study has now been modified to a 2-arm study (standard therapy +/− ZOL) in MBC patients with no bone metastases. CTC, uNTX, and PFS data will be presented from this new head-to-head analysis. Changes in CTCs out to 6 months and correlation with uNTX and PFS in this original bone metastasis cohort will also be presented.

Conclusions: This preliminary analysis suggests that the addition of ZOL to standard therapy in women with bone metastases from MBC results in a further decrease in CTC numbers at 3–5 weeks after initiation of therapy.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-18-01.

Drift or Selection: A Statistical Test of Gene Frequency Variation over Generations

The method used by Fisher and Ford (1947) to study the spread of a gene in a natural population has been modified to analyze the variation in allele frequencies from generation to generation in a common experimental procedure. A further analysis has been developed that is more sensitive to directional trends in the allele frequency over generations, and its use in detecting the action of directional selection on gene frequency at a locus is discussed. The power of each of these statistical tests is calculated for a number of cases, and the tests are applied to sets of isozyme data from Drosophila pseudoobscura and Zea mays.

registHER: Treatment outcomes in patients with HER2-positive (HER2+), hormone receptor-positive (HR+) metastatic breast cancer (MBC)

1057

Background: Approximately 50% of HER2+ breast cancers are HR+ (defined as estrogen receptor [ER] and/or progesterone receptor [PR] positive). Cross talk between growth factor and ER-dependent signaling pathways may affect growth regulation in HER2+ breast cancers. Blockade of both pathways appears to be more active than blocking either alone based on randomized trials performed in selected populations. However, the outcomes of HER2+ and HR+ MBC patients relative to those in real- life clinical practice have not been evaluated in large cohort studies. Methods: registHER is a prospective observational study of 1023 patients with newly diagnosed (within 6 months [mo]) HER2+ MBC treated in community/academic settings, enrolled from 12/03 to 2/06. Median follow-up from MBC diagnosis was 25 mo at data cutoff (1/02/08). Treatment patterns and outcomes in patients with HER2+/HR+ MBC receiving 1st-line therapy (i.e., therapies received prior to 1st progression) are described in this analysis. Results: Of the 963 (94%) treated HER2+ patients with recorded HR tumor status, 55% (533) were HR+ and 45% (430) were HR-negative. 1st-line MBC treatment regimens for HER2+/HR+ patients included endocrine therapy (E) only, 57 (10.7%); E + trastuzumab (T), 50 (9.4%); chemotherapy (C) ± E, 41 (7.7%); and C + trastuzumab (T) ± E, 361 (67.7%). Progression-free survival (PFS) and overall survival (OS) by 1st line treatment groups are in the table. Conclusions: In registHER, HER2+/HR+ patients treated with E+T had longer PFS than patients treated with E alone; E- alone median PFS is consistent with findings in prospective randomized trials. These data provide further information regarding trastuzumab's role in targeting dual pathways in HER2+/HR+ MBC patients in a real-world setting. Multivariate analysis to address potential bias from known prognostic factors that may influence treatment choice will be presented.

[Table: see text]

[Table: see text]

RIBBON-1: Randomized, double-blind, placebo-controlled, phase III trial of chemotherapy with or without bevacizumab (B) for first-line treatment of HER2-negative locally recurrent or metastatic breast cancer (MBC)

1005

Background: B in combination with weekly paclitaxel or docetaxel (D) as 1st-line therapy for MBC has improved progression-free survival (PFS) compared with the respective taxane alone in two large Phase III trials. This study investigated the addition of B to standard 1st-line chemotherapy regimens for MBC. Methods: Patients were randomized in 2:1 ratio to receive B + chemotherapy or placebo (pl) + chemotherapy. Prior to randomization, investigators chose capecitabine (Cap) (2000 mg/m2 x 14d), taxane (T) (nab-paclitaxel [260 mg/m2] or D [75 or 100 mg/m2], q3wk), or anthracycline (Ant)-based chemotherapy (q3wk). B or pl was administered at 15 mg/kg q3wk. Key eligibility criteria included MBC or locally-recurrent disease, no prior cytotoxic treatment, ECOG PS 0 or 1, HER2-negative disease and no CNS metastases. The primary endpoint was investigator-assessed PFS. Secondary endpoints included overall survival (OS), objective response rate (ORR), independent review of PFS, and safety. At progression, all patients were eligible for B with 2nd line chemotherapy. The Cap cohort and the pooled T or Ant (T + Ant) cohort were independently powered and analyzed in parallel using two-sided stratified log-rank test (Cap: 80% power to detect HR=0.75; T + Ant: 90% power to detect HR=0.7). Results: RIBBON-1 enrolled 1237 patients (Cap, 615; T, 307; Ant, 315) from 12/05 to 8/07 in 22 countries with a median follow-up of 15.6 months in the Cap cohort and 19.2 months in the T + Ant cohort. The results are summarized below. OS data are limited with only 33% of events. Safety was consistent with results of prior B trials. Conclusions: The addition of B to Cap, T; or Ant-based chemotherapy regimens used in 1st-line treatment of MBC resulted in statistically-significant improvement in PFS with a safety profile comparable to prior Phase III studies.

[Table: see text]

[Table: see text]

Multicenter phase II study of lapatinib in patients with brain metastases from HER2-positive breast cancer

PURPOSE

Brain metastases develop in one third of patients with advanced HER2+ breast cancer. Effective therapy for patients with central nervous system (CNS) progression after cranial radiation is extremely limited and represents a major clinical challenge. Lapatinib, an epidermal growth factor receptor/HER2 inhibitor, was associated with regressions of CNS lesions in a small phase 2 trial. The current study was done to further evaluate the CNS activity of lapatinib. The study was later amended to allow patients who progressed on lapatinib the option of receiving lapatinib plus capecitabine.

EXPERIMENTAL DESIGN

Eligible patients had HER2+ breast cancer, progressive brain metastases, prior trastuzumab, and cranial radiotherapy. The primary end point was CNS objective response, defined as >or=50% volumetric reduction of CNS lesion(s) in the absence of increasing steroid use, progressive neurologic signs and symptoms, or progressive extra-CNS disease.

RESULTS

Two-hundred and forty-two patients entered the study. CNS objective responses to lapatinib were observed in 6% of patients. In an exploratory analysis, 21% of patients experienced a >or=20% volumetric reduction in their CNS lesions. An association was observed between volumetric reduction and improvement in progression-free survival and neurologic signs and symptoms. Of the 50 evaluable patients who entered the lapatinib plus capecitabine extension, 20% experienced a CNS objective response and 40% experienced a >or=20% volumetric reduction in their CNS lesions.

CONCLUSIONS

This study confirms the modest CNS antitumor activity of lapatinib. Additional responses were observed with the combination of lapatinib and capecitabine. Further studies of lapatinib-based regimens for CNS metastases from HER2+ breast cancer are warranted.

Survival of patients with HER2+ metastatic breast cancer and use of trastuzumab following progression: analysis of RegistHER

Abstract #3142

Background: Most HER2+ metastatic breast cancer (MBC) patients who initially respond to trastuzumab (T)-based therapies will experience disease progression (PD). Standard practice is to discontinue the cytotoxic agent on which disease progressed, however there is evidence that tumors may remain sensitive to HER2 targeting and that there may be a potentiating effect of T on chemotherapy. We examined the treatment history of a large population of HER2+ MBC patients to assess outcomes associated with continuation of T beyond PD.&#x2028; Methods: This analysis was carried out on patients enrolled in registHER, a prospective observational study of 1023 patients with newly diagnosed (within 6 months) HER2+ MBC. Median f/u from MBC diagnosis is 25 months at the time of data cut-off (12/31/07). For those treated with T prior to first PD, we compared demographics and baseline tumor characteristics for those patients treated with or without T following first PD. Treatment with T was defined as a minimum of 21 days of therapy prior to PD. In addition, we evaluated time to second PD, and overall survival post PD (both endpoints calculated from initial PD). Overall survival (OS) was also calculated from the date of treatment initiation to death for the entire treated cohort.&#x2028; Results: Of 1023 evaluable patients, 873 (85%) were treated with any T-based first-line therapy. 622 T-treated patients progressed and 500 were subsequently treated with T following first PD. Patients who received T post first PD tended to be younger (&lt;50 years of age, 45.2% vs 29.5%) and have hormone receptor positive disease (51.4% vs 42.0%) compared with patients who did not receive T post first PD. Among all treated patients the median overall survival was 35.6 mo (25th-75th-ile:18.6-63.1 mo). Median survival post PD in the 500 patients treated with trastuzumab following first PD was 21.2 mo (25th-75th-ile:11.8-35.8mo).&#x2028; Conclusions: OS in patients on the prospective observational study registHER is longer than the OS of 25.1 months noted in the pivotal trial of first-line HER2+ MBC patients treated with T plus chemotherapy. We will present data on the association between various pre- and post-treatment factors, including the use of T beyond PD, and PFS and OS. This will include a multivariate analysis that specifically examines the association between T use in later lines and survival.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3142.

The Head to Head trial: Letrozole vs anastrozole as adjuvant treatment of postmenopausal patients with node positive breast cancer

10672

Introduction: Aromatase Inhibitors (AIs) have demonstrated both efficacy and safety advantages over tamoxifen (T) in all treatment settings in breast cancer (BC) and are becoming the new standard of care as endocrine therapy for postmenopausal patients (PM) with BC. Rationale: Cumulative evidence suggests that all AIs may not be the same, raising the question of whether there is a superior AI, and whether any specific patient populations derive differing degrees of benefit from a particular AI. In the ATAC trial, evaluating anastrozole (A) in PM patients with early breast cancer (EBC), at 33 months median follow up the risk of recurrence in the hormone receptor positive (HR+) population was reduced by 22%.The BIG 1–98 Trial, evaluating letrozole (L) in PM women with EBC, showed a significant benefit in favor of L over T at a median follow up of 26 months, with a 19% reduction in the risk of recurrence; in subgroup analyses, L significantly decreased the risk of recurrence in LN+ patients and in patients who received adjuvant chemotherapy. This study is a head to head comparison of L and A in HR+, LN+ PM patients with EBC and aims to compare L vs A in the adjuvant treatment of these patients. Design and Methods: This is a Phase IIIb open-label, randomized, multicentre study including 4000 PM patients from up to 250 international sites. PM patients with HR+, LN+ BC who have recently undergone surgery for primary BC will be randomized to either receive L 2.5 mg or A 1 mg daily. Treatment will commence following completion of standard chemotherapy (if given) and concurrently with radiotherapy (if given)Patients will receive treatment until disease recurrence/relapse for up to 5 years. Patients will be stratified by number of LN and HER2 status. The primary objective is disease free survival at 5 years for L and A. Secondary objectives include safety, overall survival, time to distant metastases and time to contralateral breast cancer. Data analysis will be conducted by an independent group of investigators. Summary: Updated patient accrual figures, including any available early safety data, will be presented at the meeting.

No significant financial relationships to disclose.

registHER: Baseline characteristics of a cohort of HER2-positive metastatic breast cancer (MBC) patients

20095

Background: HER2 is amplified in 25% of breast cancers and is associated with poor survival. registHER captures the natural history, treatment patterns and outcomes in 1000 newly-diagnosed HER2-positive MBC patients (pts) throughout the U.S. This observational study recruits pts in both academic and community centers. Methods: This ongoing prospective cohort study collects clinical, pathologic and treatment data at enrollment, quarterly until death, loss to follow-up or 3 years after the last enrollment. We describe baseline pt and clinical characteristics in registHER compared with HER2-positive MBC pts in the phase III pivotal trial (Slamon DJ, et al. N Engl J Med. 2001;344:783–792). Results: Between December 2003 and September 2005, 813 eligible pts were enrolled at 280 study sites. Most pts were seen at community-based (76%) vs academic (18%) clinics; a few pts did not fall into either category (6%). A comparison of baseline characteristics is shown below. Conclusions: registHER pts tended to have a shorter disease-free interval and more estrogen receptor positive disease than pts in the pivotal trial. Reasons for these differences could reflect trial referral and/or diagnostic testing differences. Fewer registHER patients were white, but other characteristics were similar between the two groups. These findings support the hypothesis that observational studies describe a broad patient population which may not exactly duplicate clinical trials. Within registHER, there was some variation between academic vs community clinics (eg. nodal status and adjuvant therapy). Treatment pattern analyses are ongoing.

[Table: see text]

[Table: see text]

Chemotherapy-induced alopecia: psychosocial impact and therapeutic approaches

Despite advances in the treatment of many side effects associated with chemotherapy, alopecia remains an issue that is difficult to resolve. Chemotherapy-induced alopecia (CIA) is a condition that can have profound psychosocial and quality-of-life consequences, resulting in anxiety, depression, a negative body image, lowered self-esteem, and a reduced sense of well-being. Patients who fear CIA may sometimes select regimens with less favorable outcomes or may refuse treatment. When supporting patients with CIA, health care providers should use an individualized approach with a focus placed on the actual moment of hair loss. Education, support groups, and self-care strategies are important components of any management approach. No treatment modality for preventing CIA has been clearly shown to be effective. Recent evidence suggests that new scalp hypothermic regimens may be safe and effective. There remains a critical need for effective new approaches to this problem.

Phase II Trial of Trastuzumab Followed by Weekly Paclitaxel/Carboplatin As First-Line Treatment for Patients With Metastatic Breast Cancer

Purpose

To determine the response rate of trastuzumab as first-line therapy in patients with HER-2 overexpressing metastatic breast cancer. To assess the feasibility and toxicity of weekly paclitaxel/carboplatin with or without trastuzumab following initial treatment with trastuzumab.

Patients and Methods

Sixty-one patients received trastuzumab (8 mg/kg followed by 4 mg/kg/wk) for 8 weeks. Responding patients received 8 additional weeks of trastuzumab (4 mg/kg/wk), and then proceeded to receive trastuzumab (2 mg/kg) in combination with paclitaxel 70 mg/m2 and carboplatin (area under the curve, 2) weekly for 6 weeks followed by 2 weeks rest. Stable patients after the initial 8 weeks of trastuzumab proceeded to treatment with trastuzumab, paclitaxel, and carboplatin. Patients with disease progression during the initial 8 weeks had the trastuzumab discontinued and were treated with weekly paclitaxel/carboplatin.

Results

Weekly paclitaxel/carboplatin with or without trastuzumab was well tolerated. Fifty-two patients were assessable for response and all 61 patients were assessable for survival. Seventeen (33%) of 52 patients experienced a minor/partial response to single-agent trastuzumab and received 8 additional weeks of single-agent trastuzumab. Fifteen (29%) of 52 patients had stable disease and proceeded to receive paclitaxel/carboplatin/trastuzumab. Thirty-one patients with measurable disease were assessable for response after initial single-agent trastuzumab followed by paclitaxel/carboplatin/trastuzumab. An overall response rate of 84% (eight complete responses/18 partial responses), median time to progression of 14.2 months, and median overall survival of 32.2 months was reported with the triplet combination. In the patients treated with paclitaxel/carboplatin alone after disease progression on initial single-agent trastuzumab, an overall response rate of 69% (one complete response/10 partial responses), median time to progression of 8.3 months, and median overall survival of 22.2 months was reported. Median time to progression for all 61 patients is 10 months and the median overall survival is 26.7 months.

Conclusion

This trial confirms the activity and tolerability of weekly paclitaxel/carboplatin alone or in combination with trastuzumab in women with HER-2 overexpressing metastatic breast cancer.