The Double Antibody Drug Conjugate (DAD) phase I trial: sacituzumab govitecan plus enfortumab vedotin for metastatic urothelial carcinoma

BACKGROUND

The antibody-drug conjugates sacituzumab govitecan (SG) and enfortumab vedotin (EV) are standard monotherapies for metastatic urothelial carcinoma (mUC). Given the different targets and payloads, we evaluated the safety and efficacy of SG + EV in a phase I trial in mUC (NCT04724018).

PATIENTS AND METHODS

Patients with mUC and Eastern Cooperative Oncology Group performance status ≤1 who had progressed on platinum and/or immunotherapy were enrolled. SG + EV were administered on days 1 + 8 of a 21-day cycle until progression or unacceptable toxicity. Primary endpoint was the incidence of dose-limiting toxicities during cycle 1. The number of patients treated at each of four pre-specified dose levels (DLs) and the maximum tolerated doses in combination (MTD) were determined using a Bayesian Optimal Interval design. Objective response, progression-free survival, and overall survival were secondary endpoints.

RESULTS

Between May 2021 and April 2023, 24 patients were enrolled; 1 patient never started therapy and was excluded from the analysis. Median age was 70 years (range 41-88 years); 11 patients received ≥3 lines of therapy. Seventy-eight percent (18/23) of patients experienced grade ≥3 adverse event (AE) regardless of attribution at any DL, with one grade 5 AE (pneumonitis possibly related to EV). The recommended phase II doses are SG 8 mg/kg with EV 1.25 mg/kg with granulocyte colony-stimulating factor support; MTDs are SG 10 mg/kg with EV 1.25 mg/kg. The objective response rate was 70% (16/23, 95% confidence interval 47% to 87%) with three complete responses; three patients had progressive disease as best response. With a median follow-up of 14 months, 9/23 patients have ongoing response including 6 responses lasting over 12 months.

CONCLUSIONS

The combination of SG + EV was assessed at different DLs and a safe dose for phase II was identified. The combination had encouraging activity in patients with mUC with high response rates, including clinically significant complete responses. Additional study of this combination is warranted.

Understanding breast cancer complexity to improve patient outcomes: The St Gallen International Consensus Conference for the Primary Therapy of Individuals with Early Breast Cancer 2023

The 18th St Gallen International Breast Cancer Conference held in March 2023, in Vienna, Austria, assessed significant new findings for local and systemic therapies for early breast cancer with a focus on the evaluation of multimodal treatment options. The emergence of more effective, innovative agents in both the preoperative (primary or neoadjuvant) and post-operative (adjuvant) settings has underscored the pivotal role of a multidisciplinary approach in treatment decision making, particularly when selecting systemic therapy for an individual patient. The importance of multidisciplinary discussions regarding the clinical benefits of interventions was explicitly emphasized by the consensus panel as an integral part of developing an optimal treatment plan with the 'right' degree of intensity and duration. The panelists focused on controversies surrounding the management of common ductal/no special type and lobular breast cancer histology, which account for the vast majority of breast tumors. The expert opinion of the panelists was based on interpretations of available data, as well as current practices in their professional environments, personal and socioeconomic factors affecting patients, and cognizant of varying reimbursement and accessibility constraints around the world. The panelists strongly advocated patient participation in well-designed clinical studies whenever feasible. With these considerations in mind, the St Gallen Consensus Conference aims to offer guidance to clinicians regarding appropriate treatments for early-stage breast cancer and assist in balancing the realistic trade-offs between treatment benefit and toxicity, enabling patients and clinicians to make well-informed choices through a shared decision-making process.

Genomic characterisation of hormone receptor-positive breast cancer arising in very young women

BACKGROUND

Very young premenopausal women diagnosed with hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+HER2-) early breast cancer (EBC) have higher rates of recurrence and death for reasons that remain largely unexplained.

PATIENTS AND METHODS

Genomic sequencing was applied to HR+HER2- tumours from patients enrolled in the Suppression of Ovarian Function Trial (SOFT) to determine genomic drivers that are enriched in young premenopausal women. Genomic alterations were characterised using next-generation sequencing from a subset of 1276 patients (deep targeted sequencing, n = 1258; whole-exome sequencing in a young-age, case-control subsample, n = 82). We defined copy number (CN) subgroups and assessed for features suggestive of homologous recombination deficiency (HRD). Genomic alteration frequencies were compared between young premenopausal women (<40 years) and older premenopausal women (≥40 years), and assessed for associations with distant recurrence-free interval (DRFI) and overall survival (OS).

RESULTS

Younger women (<40 years, n = 359) compared with older women (≥40 years, n = 917) had significantly higher frequencies of mutations in GATA3 (19% versus 16%) and CN amplifications (CNAs) (47% versus 26%), but significantly lower frequencies of mutations in PIK3CA (32% versus 47%), CDH1 (3% versus 9%), and MAP3K1 (7% versus 12%). Additionally, they had significantly higher frequencies of features suggestive of HRD (27% versus 21%) and a higher proportion of PIK3CA mutations with concurrent CNAs (23% versus 11%). Genomic features suggestive of HRD, PIK3CA mutations with CNAs, and CNAs were associated with significantly worse DRFI and OS compared with those without these features. These poor prognostic features were enriched in younger patients: present in 72% of patients aged <35 years, 54% aged 35-39 years, and 40% aged ≥40 years. Poor prognostic features [n = 584 (46%)] versus none [n = 692 (54%)] had an 8-year DRFI of 84% versus 94% and OS of 88% versus 96%. Younger women (<40 years) had the poorest outcomes: 8-year DRFI 74% versus 85% and OS 80% versus 93%, respectively.

CONCLUSION

These results provide insights into genomic alterations that are enriched in young women with HR+HER2- EBC, provide rationale for genomic subgrouping, and highlight priority molecular targets for future clinical trials.

P17 National antimicrobial point prevalence survey in adult inpatient mental health facilities in Ireland

Background

Antimicrobial use in mental health inpatient settings has not been extensively examined in Ireland. The Healthcare-Associated Infection and Antimicrobial Use in Long-Term Care Facilities (HALT) study 2016 found that Irish long-term care facilities caring for residents with psychiatric conditions had an antimicrobial prevalence rate of 7.7%, higher than the European average of 4.9%. National community antimicrobial prescribing guidelines are available at www.antibioticprescribing.ie. In addition, a preferred antibiotic initiative for community settings advocates prescribers to choose ‘Green’ (preferred) antibiotics over ‘Red’ (reserved) agents. Reserved agents are considered to have more adverse effects, drug interactions and potential for development of antimicrobial resistance. The patient safety implications of antimicrobial stewardship along with an ageing population, and potential drug–drug interactions between many antimicrobials and psychotropic medications prompted a review of antimicrobial use practices in mental health services.

Methods

A sample of adult inpatient mental health facilities (MHF) operated by the state's Health Service Executive (HSE) were surveyed by community antimicrobial pharmacists (AMPs) between November 2021 and January 2022. AMPs reviewed patients’ medication charts for systemic antimicrobial prescriptions in the previous 30 days in addition to medical notes and laboratory results (where available). Adherence to HSE National community antimicrobial guidelines and the systems and structures in place to support antimicrobial stewardship were assessed.

Results

In total, 1003 patients in 51 MHFs were surveyed. At the time of survey, 6.3% (n=66) patients were on a systemic antimicrobial and 15% (n=153) had received a systemic antimicrobial within the previous 30 days. Prophylaxis accounted for 50% of antibiotic use (3.3% of all patients), with the most common indication being the prevention of urinary tract infection (UTI) (58%). Prophylaxis duration exceeded six months in 61% of prescriptions. The median duration of treatment courses was seven days. The proportion of ‘Green’ (preferred) antimicrobials versus ‘Red’ (reserved) antimicrobials was 58% versus 38%. Co-amoxiclav, a ‘Red’ agent was the most commonly prescribed antibiotic for treatment of infection (31%). Adherence with choice of antimicrobial agent as per national antimicrobial guidelines was 76%; adherence of dosing regimen was 75% and adherence with recommended duration was 46%. The main themes for non-adherence with choice of agent were use of unnecessarily broad spectrum agents, nitrofurantoin prescribed in renal impairment and inappropriate formulation of nitrofurantoin chosen. Dipstick urinalysis was performed routinely (on admission and/or at designated intervals) for persons asymptomatic of UTI in 53% (n=27) of MHFs.

Conclusions

This PPS established antimicrobial use practices in HSE MHFs and identified opportunities for improvement relating to the safe and optimal use of antimicrobials. Key national recommendations from this survey were:

O02 Improving antimicrobial use in HSE older persons residential care facilities

Background

Antimicrobial use in Irish older persons residential care facilities (OP RCFs) is higher than in other European countries. In 2020/21, for the first time, an antimicrobial pharmacist (AMP) was appointed to each community healthcare organization (CHO) to monitor, develop and promote antimicrobial stewardship in community settings.

Objectives

To establish baseline antibiotic use, develop antimicrobial stewardship tools for OP RCFs, promote best practice in relation to antimicrobial stewardship (AMS) and monitor trends in antimicrobial use in HSE (state-run) OP RCFs.

Methods

A baseline point prevalence survey (PPS) of antimicrobial use was conducted across all HSE OP RCFs between October 2020 and August 2021. Following the survey, key national recommendations and AMS resources were developed in collaboration with the national Antimicrobial Resistance and Infection Control Programme. Feedback was provided to participating facilities by CHO AMPs with antimicrobial stewardship support and education for nursing and medical staff. In September 2021, monthly monitoring of antibiotic use was established in HSE OP RCFs in collaboration with local managers, to capture the proportion of antibiotics used for prophylaxis or treatment each month.

Results

A baseline PPS of antimicrobial use in 2020/21 showed that 11.9% (528/4446) of residents were on a systemic antibiotic, with 6.3% on antibiotic prophylaxis. Urinary tract infection accounted for 51% of antibiotic prescriptions. Following the baseline PPS, CHO AMPs developed an AMS toolkit for OP RCFs, engaged with nursing and medical staff to communicate PPS results, AMS resources and support implementation of AMS recommendations. Subsequently, monthly self-reporting of antimicrobial use in HSE OP RCFs was commenced in September 2021 and showed a sustained decrease in antimicrobial use with 7.9% residents on an antibiotic in Quarter 2 2022, with 2.7% on antibiotic prophylaxis.

Conclusions

Newly appointed CHO AMPs have successfully promoted AMS across HSE OP RCFs. Following audit, feedback, education, development and promotion of antimicrobial stewardship resources, there was a sustained decrease in the proportion of residents on antibiotics used for treatment and prophylaxis of infection.

88 NATIONAL ANTIMICROBIAL POINT PREVALENCE SURVEY IN HSE OLDER PERSONS RESIDENTIAL CARE FACILITIES (OPS-RCFS)

Background

The HALT study in 2016 found that residents in Irish OPS RCFs were twice as likely to be on systemic antimicrobial compared with European average (10% v 5%). National antibiotic prescribing guidelines are available at www.antibioticprescribing.ie and prescribers are encouraged to choose ‘green’ (preferred) over ‘red’ (reserved) agents. HSE Community Antimicrobial Pharmacists (AMPs) have been employed since 2020. We aimed to establish the quality and quantity of antimicrobial prescribing in OPS-RCFs to inform antimicrobial stewardship activities.

Methods

All residents in HSE OPS-RCFs were surveyed between October 2020 and August 2021. AMPs reviewed all medication charts for systemic antimicrobials prescribed within previous 30 days. Medical notes +/- laboratory results were reviewed for persons on antimicrobials. Adherence to guidelines was assessed and information obtained on practices related to antimicrobial use.

Results

The survey included 4,448 individuals in 121 OPS RCFs. 12% were on systemic antimicrobial at time of survey. 27% received an antimicrobial in the previous 30 days. 50% of antibiotic use on survey day was for prophylaxis (6.3% of all residents). Prophylaxis exceeded 6 months in 66% persons, and 12 months in 57%. There was high usage of green versus red agents (65% vs 30%). Co-amoxiclav (red) was most commonly prescribed antimicrobial to treat infection (19%). 42% of sites reported routine use of dipstick urinalysis to support diagnosis of UTI in asymptomatic residents. 36% of sites did not have onsite electronic laboratory access. 61% of facilities did not record residents’ pneumococcal vaccination status.

Conclusion

Key national recommendations: Review all UTI prophylaxis within 6 months of initiation with view to de-prescribing.Cease routine use of dipstick urinalysis to support diagnosis of UTI for asymptomatic persons.Electronic access to laboratory results on-site required to support timely decision-making.All staff should be aware of the national antimicrobial guidelines.Pneumococcal vaccine status should be determined, and provided as necessary.

Risk-adapted modulation through de-intensification of cancer treatments: an ESMO classification

BACKGROUND

The landscape of clinical trials testing risk-adapted modulations of cancer treatments is complex. Multiple trial designs, endpoints, and thresholds for non-inferiority have been used; however, no consensus or convention has ever been agreed to categorise biomarkers useful to inform the treatment intensity modulation of cancer treatments.

METHODS

An expert subgroup under the European Society for Medical Oncology (ESMO) Precision Medicine Working Group shaped an international collaborative project to develop a classification system for biomarkers used in the cancer treatment de-intensification, based on a tiered approach. A group of disease-oriented clinical, translational, methodology and public health experts, and patients' representatives provided an analysis of the status quo, and scanned the horizon of ongoing clinical trials. The classification was developed through multiple rounds of expert revisions and inputs.

RESULTS

The working group agreed on a univocal definition of treatment de-intensification. Evidence of reduction in the dose-density, intensity, or cumulative dose, including intermittent schedules or shorter treatment duration or deletion of segment(s) of the standard regimens, compound(s), or treatment modality must be demonstrated, to define a treatment de-intensification. De-intensified regimens must also portend a positive impact on toxicity, quality of life, health system burden, or financial toxicity. ESMO classification categorises the biomarkers for treatment modulation in three tiers, based on the level of evidence. Tier A includes biomarkers validated in prospective, randomised, non-inferiority clinical trials. The working group agreed that in non-inferiority clinical trials, boundaries are highly dependent upon the disease scenario and endpoint being studied and that the absolute differences in the outcomes are the most relevant measures, rather than relative differences. Biomarkers tested in single-arm studies with a threshold of non-inferiority are classified as Tier B. Tier C is when the validation occurs in prospective-retrospective quality cohort investigations.

CONCLUSIONS

ESMO classification for the risk-guided intensity modulation of cancer treatments provides a set of evidence-based criteria to categorise biomarkers deemed to inform de-intensification of cancer treatments, in risk-defined patients. The classification aims at harmonising definitions on this matter, therefore offering a common language for all the relevant stakeholders, including clinicians, patients, decision-makers, and for clinical trials.

Continuous versus intermittent extended adjuvant letrozole for breast cancer: final results of randomized phase III SOLE (Study of Letrozole Extension) and SOLE Estrogen Substudy

BACKGROUND

Late recurrences in postmenopausal women with hormone receptor-positive breast cancers remain an important challenge. Avoidance or delayed development of resistance represents the main objective in extended endocrine therapy (ET). In animal models, resistance was reversed with restoration of circulating estrogen levels during interruption of letrozole treatment. This phase III, randomized, open-label Study of Letrozole Extension (SOLE) studied the effect of extended intermittent letrozole treatment in comparison with continuous letrozole. In parallel, the SOLE estrogen substudy (SOLE-EST) analyzed the levels of estrogen during the interruption of treatment.

PATIENTS AND METHODS

SOLE enrolled 4884 postmenopausal women with hormone receptor-positive, lymph node-positive, operable breast cancer between December 2007 and October 2012 and among them, 104 patients were enrolled in SOLE-EST. They must have undergone local treatment and have completed 4-6 years of adjuvant ET. Patients were randomized between continuous letrozole (2.5 mg/day orally for 5 years) and intermittent letrozole treatment (2.5 mg/day for 9 months followed by a 3-month interruption in years 1-4 and then 2.5 mg/day during all of year 5).

RESULTS

Intention-to-treat population included 4851 women in SOLE (n = 2425 in the intermittent and n = 2426 in the continuous letrozole groups) and 103 women in SOLE-EST (n = 78 in the intermittent and n = 25 in the continuous letrozole groups). After a median follow-up of 84 months, 7-year disease-free survival (DFS) was 81.4% in the intermittent group and 81.5% in the continuous group (hazard ratio: 1.03, 95% confidence interval: 0.91-1.17). Reported adverse events were similar in both groups. Circulating estrogen recovery was demonstrated within 6 weeks after the stop of letrozole treatment.

CONCLUSIONS

Extended adjuvant ET by intermittent administration of letrozole did not improve DFS compared with continuous use, despite the recovery of circulating estrogen levels. The similar DFS coupled with previously reported quality-of-life advantages suggest intermittent extended treatment is a valid option for patients who require or prefer a treatment interruption.

Lessons from a theory of change-driven evaluation of a global mental health funding portfolio

BACKGROUND

Given the underinvestment in global mental health to-date, it is important to consider how best to maximize the impact of existing investments. Theory of Change (ToC) is increasingly attracting the interest of funders seeking to evaluate their own impact. This is one of four papers investigating Grand Challenges Canada's (GCC's) first global mental health research funding portfolio (2012-2016) using a ToC-driven approach.

METHODS

A portfolio-level ToC map was developed through a collaborative process involving GCC grantees and other key stakeholders. Proposed ToC indicators were harmonised with GCC's pre-existing Results-based Management and Accountability Framework to produce a "Core Metrics Framework" of 23 indicators linked to 17 outcomes of the ToC map. For each indicator relevant to their project, the grantee was asked to set a target prior to the start of implementation, then report results at six-month intervals. We used the latest available dataset from all 56 projects in GCC's global mental health funding portfolio to produce a descriptive analysis of projects' characteristics and outcomes related to delivery.

RESULTS

12,999 people were trained to provide services, the majority of whom were lay or other non-specialist health workers. Most projects exceeded their training targets for capacity-building, except for those training lay health workers. Of the 321,933 people screened by GCC-funded projects, 162,915 received treatment. Most projects focused on more than one disorder and exceeded all their targets for screening, diagnosis and treatment. Fewer people than intended were screened for common mental disorders and epilepsy (60% and 54%, respectively), but many more were diagnosed and treated than originally proposed (148% and 174%, respectively). In contrast, the three projects that focused on perinatal depression exceeded screening and diagnosis targets, but only treated 43% of their intended target.

CONCLUSIONS

Under- or over-achievement of targets may reflect operational challenges such as high staff turnover, or challenges in setting appropriate targets, for example due to insufficient epidemiological evidence. Differences in delivery outcomes when disaggregated by disorder suggest that these challenges are not universal. We caution implementers, funders and evaluators from taking a one-size-fits all approach and make several recommendations for how to facilitate more in-depth, multi-method evaluation of impact using portfolio-level ToC.

Gambling harm is everybody's business: A public health approach and call to action

There is a growing consensus that gambling is a public health issue and that preventing gambling related harms requires a broad response. Although many policy decisions regarding gambling are made at a national level in the UK, there are clear opportunities to take action at local and regional levels to prevent the negative impacts on individuals, families and local communities. This response goes beyond the statutory roles of licencing authorities to include amongst others the National Health Service (NHS), the third sector, mental health services, homelessness and housing services, financial inclusion support. As evidence continues to emerge to strengthen the link between gambling and a wide range of risk factors and negative consequences, there is also a strong correlation with health inequalities. Because the North of England experiences increasing health inequalities, it offers an opportunity as a specific case study to share learning on reducing gambling-related harms within a geographic area. This article describes an approach to gambling as a public health issue identifying it as needing a cross-cutting, systemwide multisectoral approach to be taken at local and regional levels. Challenges at national and local levels require policy makers to adopt a ‘health in all policy’ approach and use the best evidence in their future decisions to prevent harm. A whole systems approach which aims to reduce poverty and health inequalities needs to incorporate gambling harm within place-based planning and draws on the innovative opportunities that exist to engage local stakeholders, builds local leadership and takes a collaborative approach to tackling gambling-related harms. This whole systems approach includes the following: (1) understanding the prevalence of gambling related harms with insights into the consequences and how individuals, their family and friends and wider community are affected; (2) ensuring tackling gambling harms is a key public health commitment at all levels by including it in strategic plans, with meaningful outcome measures, and communicating this to partners; (3) understanding the assets and resources available in the public, private and voluntary sectors and identifying what actions are underway; (4) raising awareness and sharing data, developing a compelling narrative and involving people who have been harmed and are willing to share their experience; (5) ensuring all regulatory authorities help tackle gambling-related harms under a ‘whole council’ approach.

•

This piece presents the case for why gambling is a particularly unique public health issue which requires a cross-cutting, systemwide multisectoral approach.

•

It explores opportunities for action at national and local level, using examples of work underway.

•

It concludes with a call to action using lesson learnt from managing harms from similar public health threats.

Identifying oncogenic drivers associated with increased risk of late distant recurrence in postmenopausal, estrogen receptor-positive, HER2-negative early breast cancer: results from the BIG 1-98 study

BACKGROUND

In postmenopausal, estrogen receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative early breast cancer, the risk for distant recurrence can extend beyond 5 years of adjuvant endocrine therapy. This study aims to identify genomic driver alterations associated with late distant recurrence.

PATIENTS AND METHODS

Next generation sequencing was used to characterize driver alterations in primary tumors from a subset of 764 postmenopausal estrogen receptor-positive/HER2-negative patients from the BIG 1-98 randomized trial. Late distant recurrence events were defined as ≥5 years from time of randomization). The association of driver alterations with distant recurrence-free interval in early and late time periods was assessed using Cox regression models. Multivariable analyses were carried out to adjust for clinicopathological factors. Weighted analysis methods were used in order to correct for over-sampling of distant recurrences.

RESULTS

A total of 538 of 764 (70%) samples were successfully sequenced including 88 (63%) early and 52 (37%) late distant recurrence events after a median follow up of 8.1 years. In univariable analysis for late distant recurrence, PIK3CA mutations (58.8%) were significantly associated with reduced risk [hazard ratio (HR) 0.40, 95% confidence interval (CI) 0.20-0.82, P = 0.012], whereas amplifications on chromosome 8p11 (10.9%) (HR 4.79, 95% CI 2.30-9.97, P < 0.001) and BRCA2 mutations (2.3%) (HR 5.39, 95% CI 1.51-19.29, P = 0.010) were significantly associated with an increased risk. In multivariable analysis, only amplifications on 8p11 (P = 0.002) and BRCA2 mutations (P = 0.013) remained significant predictors.

CONCLUSIONS

In estrogen receptor-positive/HER2-negative postmenopausal early breast cancer, PIK3CA mutations were associated with reduced risk of late distant recurrence, whereas amplifications on 8p11 and BRCA2 mutations were associated with increased risk of late distant recurrence. The characterization of oncogenic driver alterations may aid in refining treatment choices in the late disease setting, and help identify potential drug targets for testing in future trials.

Estimating the benefits of therapy for early-stage breast cancer: the St. Gallen International Consensus Guidelines for the primary therapy of early breast cancer 2019

BACKGROUND

The 16th St. Gallen International Breast Cancer Conference 2019 in Vienna, Austria reviewed substantial new evidence on loco-regional and systemic therapies for early breast cancer.

DESIGN

Treatments were assessed in light of their intensity, duration and side-effects, estimating the magnitude of clinical benefit according to stage and biology of the disease. The Panel acknowledged that for many patients, the impact of adjuvant therapy or the adherence to specific guidelines may have modest impact on the risk of breast cancer recurrence or overall survival. For that reason, the Panel explicitly encouraged clinicians and patients to routinely discuss the magnitude of benefit for interventions as part of the development of the treatment plan.

RESULTS

The guidelines focus on common ductal and lobular breast cancer histologies arising in generally healthy women. Special breast cancer histologies may need different considerations, as do individual patients with other substantial health considerations. The panelists' opinions reflect different interpretation of available data and expert opinion where is lack of evidence and sociocultural factors in their environment such as availability of and access to medical service, economic resources and reimbursement issues. Panelists encourage patient participation in well-designed clinical studies whenever available.

CONCLUSIONS

With these caveats in mind, the St. Gallen Consensus Conference seeks to provide guidance to clinicians on appropriate treatments for early-stage breast cancer and guidance for weighing the realistic tradeoffs between treatment and toxicity so that patients and clinical teams can make well-informed decisions on the basis of an honest reckoning of the magnitude of clinical benefit.

Abstract PD3-08: Assessment of the tumor immune environment in inflammatory breast cancer treated with neoadjuvant dual-HER2 blockade

Background: Inflammatory breast cancer (IBC) is an aggressive form of breast cancer that remains relatively understudied. We examined the efficacy of neoadjuvant dual-HER2 blockade (trastuzumab (H) and pertuzumab (P)) combined with paclitaxel (T) in HER2+ IBC, including a planned analysis to elucidate associations between the tumor immune microenvironment profile and response to therapy.

Methods: An IRB-approved, single-arm phase II trial for patients (pts) with newly diagnosed HER2+ IBC was conducted. Pts had a pre-treatment biopsy of the affected breast (D1) followed by a loading dose of HP. A second biopsy was performed 1 week (wk) later (D8), when T (80mg/m2/wk x 16 wks) was added to HP. Responding pts underwent modified radical mastectomy (MRM) where residual disease was collected. The primary objective was to determine the rate of pathologic complete response (pCR) defined as ypT0/isN0. Residual Cancer Burden (RCB) was also determined. Tumor specimens from D1, D8 and MRM were assessed for disease cellularity and scored for percentage of tumor infiltrating lymphocytes (TILs): low=0-10%, intermediate=11-59%, high&gt;60%. RNA-sequencing was performed on tumor tissue from D1 and D8 to explore the impact of short-term HP treatment on the tumor transcriptomic profile and to identify potential predictors of pCR.

Results: 23 pts with HER2+ IBC were enrolled between 8/2013-6/2017. Mean age was 48 years (range 32-74); 11 pts (48%) had estrogen and progesterone receptor (ER/PR) negative disease. Matched tumor biopsies (D1, D8) were obtained in all 23 pts; 21 underwent MRM; 1 was lost to follow-up and 1 had disease progression. In the intent to treat analysis, 10/23 (43%) pts achieved a pCR and 7 (30%) had RCB-1. Ten of the 22 evaluable pts achieved a pCR (45.5%). TILs were evaluable in 20/23 (87%) matched tumor biopsies (D1, D8). Among the D1 biopsy specimens: 19 (95%) had low levels, 2 (10%) had intermediate levels, and none had high levels. When D1 TIL levels were compared with D8 levels, 3(15%) had an increase in TILs, 16(80%) had no change in TIL levels, and 1(5%) had a decrease in the level of TILs. Both samples with intermediate levels and 2 of 3 samples with high levels of TILs on D1 and D8 were seen in ER/PR negative disease. An evaluation of biopsy specimens associated with subsequent pCR using GO enrichment analysis from the RNA-Seq data showed significant upregulation of several immune-process related gene expression signatures both at D1 and D8 (e.g. antigen processing and presentation, TCR signaling, NK cell cytotoxicity, p-value: 2.99E-48 to 1.39E-16) when compared with those associated with residual disease at the time of MRM. Across the entire cohort, D8 biopsies showed evidence of upregulated anti-tumor immunity compared to D1 biopsies (p-value: 9.57E-06 to 0.012). Notably, this change from D1 to D8 was largely restricted to tumors that achieved a pCR.

Conclusion: THP for 16 weeks was a highly effective treatment for HER2+ IBC. Immune activation as determined by gene expression signatures predicted pCR, and moreover upregulation of anti-tumor immunity after 1 wk of HP might further predict a complete pathologic response to therapy. ClinicalTrials.gov identifier: NCT01796197

Citation Format: Pernas S, Goel S, Harrison BT, Hu J, Johnson N, Regan M, Chichester LA, Nakhlis F, Schlosnagle EJ, Winship G, Guerriero JL, Parsons H, Mittendorf EA, Overmoyer B. Assessment of the tumor immune environment in inflammatory breast cancer treated with neoadjuvant dual-HER2 blockade [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 PD3-08.

Abstract OT2-04-03: Examining personalized radiation therapy (EXPERT): A randomised phase III trial of adjuvant radiotherapy vs observation in patients with molecularly characterized luminal A breast cancer

Background

Radiation therapy (RT) after breast conserving surgery (BCS) is the current standard of care for patients with early stage breast cancer. However, individual absolute recurrence risks and hence benefits of RT vary substantially. A study showed significant association between local recurrence (LR) risk and PAM50-defined intrinsic subtypes and Risk of Recurrence scores (ROR).1

The objective of EXPERT, a co-lead study of Breast Cancer Trials-Australia & New Zealand (BCT-ANZ), and Breast International Group (BIG), is to optimize local therapy for early breast cancer through precise individualized quantification of LR risk to identify patients for whom RT after BCS may be safely omitted.

Trial design

This is a randomized, non-inferiority, phase III study of women who plan to receive adjuvant endocrine therapy for Prosigna (PAM50)-defined luminal A breast cancer with ROR ≤60 resected by BCS.

Women are randomized to receive adjuvant whole breast RT and endocrine therapy or endocrine therapy alone and followed-up for 10 years after randomization.

Major eligibility criteria

Females aged ≥50 years; histologically confirmed invasive breast carcinoma ≤2 cm, grade 1 or 2, ER and PgR ≥10%, HER2-negative and node-negative; treated by BCS with negative margins for invasive carcinoma and associated DCIS; Prosigna (PAM50)-defined Luminal A subtype and ROR ≤60; and plan to receive adjuvant endocrine therapy.

Specific aims

Primary: To determine if omission of RT is not inferior to RT in terms of LR-free interval after BCS.

Secondary: To evaluate the impact of omission of RT on regional, local-regional and distant recurrence-free interval; disease-free survival (DFS); invasive DFS; overall survival; salvage RT or mastectomy rate; toxicity; endocrine therapy adherence; patient reported outcomes; and health economic outcomes.

Statistical methods

An estimated 5-year LR rate in the target population is expected to be 1% with RT. A rate of 4% is considered non-inferior as a worthwhile trade-off against RT toxicity. Using O'Brien-Fleming boundary for rejecting non-inferiority, 29 LR events are required for final analysis expected 8 years after the first patient is randomized. Two interim analyses will be conducted after 10 and 21 events. If the stratified log-rank test statistic exceeds the upper boundary at interim or final analysis, the hypothesis of non-inferiority will be rejected and it will be concluded that no RT is inferior to RT.

Accrual: Target (1170), actual: 82 (June 2018)

The study was activated in Australia in August 2017, with global activation planned for Q4 2018. Recruitment is expected to be completed in 4.5 years.

Contact information

Professor Boon Chua, UNSW Sydney and Prince of Wales Hospital, NSW, Australia; email boon.chua@health.nsw.gov.au; T +61 2 49255239. Registration: NCT02889874

References

Fitzal F, Filipits M, Fesl C, et al. Predicting local recurrence using PAM50 in postmenopausal endocrine responsive breast cancer patients. JCO 2014;32(15 suppl):1008.

Citation Format: Chua BH, Gray K, Krishnasamy M, Regan M, Zdenkowski N, Loi S, Mann B, Forbes JF, Wilcken N, Spillane A, Martin A, Badger H, Jafari S, Fong A, Mavin C, Corachan S, Arahmani A, Martinez J-L, Francis P. Examining personalized radiation therapy (EXPERT): A randomised phase III trial of adjuvant radiotherapy vs observation in patients with molecularly characterized luminal A breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-04-03.

Abstract P5-12-04: A new method of data analysis to derive DNA methylation signatures that stratify risk of recurrence in triple negative breast cancer

Background: Triple negative breast cancer (TNBC) accounts for 10-17% of all breast cancer and is more likely to be of higher histological grade, poorly differentiated, associated with a higher recurrence rate and with decreased overall survival. The clinical course of a TNBC patient remains difficult to predict, as tumors with homogenous morphological characteristics may vary in response to therapy and have divergent outcomes. Therefore, additional analytical methods are needed to better classify TNBC. Our goal is to refine the analysis of methylome datasets to derive reliable molecular signatures that can distinguish TNBC patients with good outcomes who may benefit from less aggressive treatment, from those with poor outcomes who would be candidates for more aggressive treatments.

Methods: Our laboratory has conducted and reported, in this meeting, results from analysis of 450k methylation array data on a discovery set of 53 high-risk TNBC cases and 62 low-risk controls treated by locoregional therapy alone, as well as 5 normal breast tissue samples. High-risk cases were defined as patients that relapsed within 0.5 to 6.5 years from the time of diagnosis, while low-risk controls had no relapse and &gt;4 year recurrence-free intervals (RFI). In this work, we devised and applied a novel methylation biomarker discovery program named Hypermethylated Outlier Detector (HOD) that emphasizes the selection of highly methylated markers in cases compared to controls, to find a high-risk signature in the TNBC discovery set. The methylation signature identified by HOD was interrogated in a test set of 50 TNBCs (with 16 recurrences) that did not receive chemotherapy, and in a second test set of 131 TNBCs (with 33 recurrences) that did receive chemotherapy.

Results: HOD identified 39 hypermethylated markers (beta &gt;0.20) that could accurately distinguish between the high-risk cases and the low-risk controls in the discovery set of TNBCs (n=115) treated with locoregional therapy alone. In the test set of TNBC (n=50) with no chemotherapy the 39 markers distinguished high from low risk individuals (likelihood ratio test P=0.049). In a second test set of TNBC (n=131) that received chemotherapy the 39 hypermethylated markers again distinguished high from low risk individuals (likelihood ratio test P=0.0043).

Conclusions: We have presented evidence that a methylation signature identified by HOD can be used to identify TNBC patients that have a high-risk of relapse regardless of receiving chemotherapy. This methylation signature could potentially be used to inform physician decisions on therapeutic strategies for TNBC patients. This could ultimately lead to less aggressive treatment given to patients possessing a methylation profile consistent with a better prognosis. Conversely, patients with hypermethylation in the 39 markers will likely benefit from a more aggressive course of treatment.

Citation Format: Downs BM, Cope LM, Fackler MJ, Cho S, Wolff AC, Regan MM, Sukumar S, Umbricht CB. A new method of data analysis to derive DNA methylation signatures that stratify risk of recurrence in triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-12-04.

Abstract P4-14-01: Estrogen levels in premenopausal patients (pts) with hormone-receptor positive (HR+) early breast cancer (BC) receiving adjuvant triptorelin (Trip) plus exemestane (E) or tamoxifen (T) in the SOFT trial: SOFT-EST substudy final analysis

Background: Optimal endocrine therapy for premenopausal pts with early HR+ BC may depend on complete estrogen suppression with GnRH analog, which is crucial when using concurrent aromatase inhibitors (AIs). SOFT-EST is a prospective substudy of the phase 3 SOFT trial aiming to describe estradiol (E2), estrone (E1) and estrone sulphate (E1S) during the first 4 years (y) of monthly Trip+E/T and to assess if there were suboptimally estrogen suppressed (SES) pts in the E+Trip group. Secondary objectives included associations of baseline (BL) factors with SES, early SES with later SES, and SES with disease-free survival (DFS; exploratory objective).

Methods: Patients from select centers who consented and enrolled in SOFT, selected Trip as ovarian function suppression method, and were randomized to E+Trip or T+Trip were eligible for SOFT-EST until the accrual goal (120 pts: 90 E+Trip; 30 T+Trip). Prem status for SOFT eligibility was based on local E2. Blood sampling timepoints were 0, 3, 6, 12, 18, 24, 36 & 48 months (m) until Trip stopped. Serum estrogens were measured centrally by high specificity/sensitivity GC/MSMS and were not available during the study. For 4y analyses, SES was defined as E2 levels &gt;2.72 pg/mL in ≥2 post-BL samples (E2 levels not consistent with postmenopausal (PM) status on AIs [Smith IE, JCO 2006]), or vaginal bleeding &gt;3m after Trip start, or pregnancy. We explored 2 additional cutoffs: &gt;10 pg/mL (clearly inconsistent with PM status on AIs) and &gt;20 pg/mL (inconsistent with GnRH analog-related PM status). The analysis is intention-to-treat based on E/T assignment; as-treated analyses are forthcoming.

Results: From Mar 2009 to Jan 2011,109 pts (E/T=83/26) started Trip and had ≥2 samples drawn. In pts assigned E+Trip, median reductions from BL in E1, E2 and E1S were &gt;95% at all timepoints and significantly lower than in T+Trip. Post-BL E2 geometric mean ranged 0.8-1.3 pg/mL in E+Trip and 16.5-18.3 pg/mL in T+Trip. 21 (25%), 11 (13%) and 6 (7%) pts assigned to E+Trip had E2&gt;2.72, &gt;10, and &gt;20 pg/mL in ≥2 post BL samples or vaginal bleeding (n=3), respectively. Early SES [(≥1 E2 value &gt;2.72 pg/mL or vaginal bleeding in the firsty] predicted later SES [≥1 E2 value &gt;2.72 or vaginal bleeding thereafter (n=1); p&lt;0.001]. BL factors related to SES were higher E2, lower FSH and lower LH values (p=0.02, p&lt;0.01, p&lt;0.01 respectively). 12m FSH levels were not related to SES. In pts assigned E+Trip, after 6y median follow-up, DFS events were seen in 0 of 21 pts with SES vs 5 of 62 pts without SES.

Conclusions: Most pts on E+Trip had a profound E2 drop consistent with postmenopausal status on AI, but &gt;20% assigned to E+Trip had ≥2 E2 values &gt;2.72 pg/mL and 4% had vaginal bleeding, with those having higher E2, lower FSH/LH at BL being at higher risk. SES at 12m predicted subsequent SES. Few DFS events limit the ability to assess clinical relevance of SES with disease outcomes.

BL characteristicsN-109Prior chemo60 (55%)Amenorrhea39 (36%)Age &lt;35y8 (7%) Median (range)Age, y44 (25-53)BMI, kg/m224 (22-28)Estrogen (pg/mL) E252 (7-119)E141 (24-70)E1S894 (304-1320)FSH/LH (IU/L) FSH15 (7-47)LH11 (6-26)

Citation Format: Bellet M, Gray K, Francis P, Láng I, Ciruelos E, Lluch A, Ángel Climent M, Catalán G, Avella A, Bohn U, González-Martin A, Zaman K, Ferrer R, Azaro A, Rajasekaran A, De la Peña L, Fleming G, Regan MM. Estrogen levels in premenopausal patients (pts) with hormone-receptor positive (HR+) early breast cancer (BC) receiving adjuvant triptorelin (Trip) plus exemestane (E) or tamoxifen (T) in the SOFT trial: SOFT-EST substudy final 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 P4-14-01.

Abstract P4-08-09: DNA methylation markers predict recurrence-free interval in triple-negative breast cancer

BACKGROUND. Chemotherapy remains the treatment mainstay for triple-negative breast cancer (TNBC). Nevertheless, randomized trials have shown that not all TNBC require it, nor does it benefit all patients that receive it. Molecular tools to risk-stratify TNBC are currently lacking. In light of the importance of epigenetic processes modulating gene expression, we performed an array-based genome-wide DNA methylation search in well-documented institutional and clinical trial cohorts of TNBC for markers that can distinguish breast cancers with a favorable natural history from those with a high risk of recurrence.

METHODS. We performed an array-based genome-wide DNA methylation survey of well-documented institutional and clinical trial cohorts of TNBC and conducted molecular marker discovery on institutional TNBCs (115 patient samples; 53 recurrences) treated by locoregional therapy (LRT) alone. The identified hypermethylated gene signatures were then tested in a TNBC cohort (50 patient samples; 16 recurrences) from the no chemotherapy arms of IBCSG trials VIII and IX, and in a separate combined cohort of TNBCs (131 patient samples; 33 recurrences) treated with chemotherapy from an institutional repository and from IBCSG trials VIII and IX. Cross platform validation was conducted using quantitative multiplexed methylation specific PCR (QM-MSP) on hypermethylated markers in samples from both the Discovery Set and IBCSG LRT Test Set.

RESULTS. We identified methylation signatures in the discovery cohort consisting of 100 or 30 CpG probes that discriminated patients who remained recurrence-free from those with recurrent disease. These signatures were then tested in the IBCSG no chemotherapy cohort, and we found that hypermethylation was associated with shorter recurrence-free interval (RFI). A significant association of both 100 CpG (P&lt;0.0001) and 30 CpG (P=0.0021) signatures with shorter RFI was found in the combined institutional and IBCSG chemotherapy cohort. We observed an enrichment of methylation probes residing on chromosome 19, particularly within 19q13.41-43, that significantly correlated with RFI following chemotherapy. QM-MSP results reflected that of the methylation array [Spearman correlation coefficient of r = 0.495 (P = 0.0009)] indicating that the relationship between high methylation and short RFI is detectable independent of analytical platform. We also observed enrichment for Chromosome 19-specific probes within the 100 and 30 probe sets. While only 5% of all CpG markers are located within Chr19, 15% of the 100 CpG set, 37% of the 30 CpG set, and 47% of the 17 CpGs that are statistically significantly correlated with RFI in the chemotherapy group reside on the Chr19, mostly within 19q13.41-43.

CONCLUSIONS. Methylation markers may be of prognostic importance in TNBC and our findings should be validated in additional clinical trial cohorts.

Citation Format: Fackler MJ, Cho SS, Cope LM, Gabrielson E, Wilsbach K, Lynch C, Marks JR, Geradts J, Regan MM, Viale G, Wolff AC, Umbricht CB, Sukumar S. DNA methylation markers predict recurrence-free interval in triple-negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-09.

Evaluation of Cryopreserved Arteries as Alternative Small Vessel Prostheses

Biologic or synthetic grafts have had limited success in small vessel applications. Studies were initiated to assess the potential use of cryopreserved (CP) arteries as coronary artery bypass conduits. Sheep carotid arteries (internal diameter: 4 mm; length: 10 cm) were cryopreserved in a nutrient media containing 10% DMSO and were stored in a nitrogen vapor at -150°C. After thawing, histological, enzyme-histochemical and functional studies showed slight histological alterations, preservation of enzymal activities and an abolition of the contractile response. In a sheep model, arterial substitution of a 10 cm segment of carotid artery was realised by implantation of fresh autografts (n=4); fresh allografts (n=9) and CP allografts (n=9). After 3 months, all autografts were patent with slight histological alterations. Fresh and CP allografts showed similar modifications: patency rate was 7/9 in both groups. Intimal thickening with cell proliferation was seen in fresh (3/7) and CP (4/8) arteries; loss of smooth muscle medial cells was constant. Adventitia was always involved by a marked inflammatory reaction. One characteristic of CP allografts was the frequent presence of large dystrophic calcifications. In conclusion, morphologic and functional arterial changes occurred after freezing and thawing. In spite of vascular rejection, the patency rate of allografts after 3 months of implantation in arterial circulation remained high and does not seem influenced by cryopreservation.

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

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

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

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

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

Citation Format: Overmoyer B, Regan M, Hu J, Nakhlis F, Dominici L, Lin NU, Freedman R, Morganstern DE, Partridge AH, Schlosnagle EJ, Hirshfield-Bartek J, Bellon J, Morikawa A, Harrison BT, Winer E. Weekly paclitaxel, pertuzumab and trastuzumab (TPH) neoadjuvant therapy for HER2 positive inflammatory breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-15-11.

Abstract GS4-02: Randomized comparison of adjuvant aromatase inhibitor exemestane (E) plus ovarian function suppression (OFS) vs tamoxifen (T) plus OFS in premenopausal women with hormone receptor positive (HR+) early breast cancer (BC): Update of the combined TEXT and SOFT trials

Background: The combined results of TEXT and SOFT, after 5.7 years median follow-up, found adjuvant E+OFS significantly improved disease-free survival (DFS) vs T+OFS in premenopausal women with HR+ BC (Pagani et al, NEJM 2014). Follow-up was immature for overall survival (OS). We report a planned update with visit cut-off of 31Dec16 after 9 years median follow-up.

Methods: TEXT and SOFT enrolled premenopausal women with HR+ early BC from Nov 2003 to Apr 2011 (2660 TEXT, 3047 SOFT in the intention-to-treat populations). TEXT randomized women within 12wk of surgery to 5 yrs E+OFS vs T+OFS; chemotherapy (CT) was optional and concurrent with OFS. SOFT randomized women to 5 yrs E+OFS vs T+OFS vs T alone, within 12wk of surgery if no CT planned, or within 8mo of completing (neo)adjuvant CT after premenopausal status was (re-)established. OFS was by choice of 5yr GnRH agonist triptorelin, oophorectomy or ovarian irradiation. Both trials were stratified by CT use. The primary endpoint was DFS: randomization until invasive local, regional, distant recurrence or contralateral breast; invasive second malignancy; death. Secondary endpoints included invasive breast cancer-free interval (BCFI), distant recurrence-free interval (DRFI) and OS. Stratified Cox models estimated hazard ratios; Kaplan-Meier method estimated 8yr endpoint rates. NCT00066703/NCT00066690.

Results: DFS for patients assigned E+OFS (n=2346) continued to be significantly improved over T+OFS (n=2344): 8yr DFS was 86.8% vs. 82.8%. The 8yr BCFI was improved by 4.1% (89.3% vs 85.2%) and 8yr DRFI by 2.1% (91.8% vs 89.7%). There was no difference in OS in patients assigned E+OFS vs T+OFS: 93.4% vs 93.3% OS at 8yrs. For 1996 women without CT there have been 45 deaths, with 98% OS at 8yrs with both treatments.

EndpointN. EventsHazard Ratio (95% CI) E+OFS vs T+OFSDFS7200.77 (0.67-0.90); P&lt;0.001BCFI6000.74 (0.63-0.87)DRFI4330.80 (0.65-0.96)OS3200.98 (0.79-1.22)

Overall toxicity was not significantly worse with E+OFS than with T+OFS (32% vs 31% grade 3-4 targeted AEs). Hot flashes, musculoskeletal symptoms and hypertension were the most frequent targeted grade 3-4 AEs. Overall, 15% of patients stopped all protocol-assigned treatment early. Patients assigned E+OFS had increased risk of assigned oral endocrine therapy cessation (25% vs 19% for patients assigned T+OFS by 4yrs) but not of triptorelin cessation (18% vs 19% by 4yrs, respectively).

Conclusions: After 9 yrs median follow-up, adjuvant E+OFS, as compared with T+OFS, shows a sustained reduction of the risk of recurrence but did not improve overall survival. As in postmenopausal women, oncologists need to consider potential absolute benefits and properly select patients at sufficient risk for recurrence for whom E+OFS seems indicated. Follow-up continues, which will further clarify the effect of E+OFS for safety, late recurrence and overall survival.

Citation Format: Pagani O, Regan MM, Fleming GF, Walley BA, Colleoni M, Láng I, Gomez HL, Tondini C, Burstein HJ, Goetz MP, Ciruelos EM, Stearns V, Debled M, Martino S, Geyer Jr CE, Pinotti G, Coates AS, Goldhirsch A, Gelber RD, Francis PA. Randomized comparison of adjuvant aromatase inhibitor exemestane (E) plus ovarian function suppression (OFS) vs tamoxifen (T) plus OFS in premenopausal women with hormone receptor positive (HR+) early breast cancer (BC): Update of the combined TEXT and SOFT trials [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 GS4-02.

Abstract P1-10-06: A randomized phase II trial evaluating the endocrine activity and efficacy of neoadjuvant degarelix versus triptorelin in premenopausal patients receiving letrozole for primary endocrine responsive breast cancer (TREND; IBCSG 41-13)

Background: Neoadjuvant endocrine therapy (NET) with gonadotropin-releasing hormone (GnRH) agonist and aromatase inhibitors is effective in selected premenopausal patients (pts). Degarelix, an antagonist of GnRH, has immediate onset of action through binding to GnRH receptors in the pituitary gland and thereby suppressing the production of LH and FSH. Its suppressing activity in premenopausal women might be faster and free of estrodial breakthrough on continued treatment compared with a GnRH angonist, and thereby provide significant clinical value for pts who are candidates for short-term NET.

Methods: Eligible pts were premenopausal women with cT2-4b, any nodal stage, ER and PgR &gt;50%, HER2-negative (by IHC and/or ISH) breast cancer who were not candidates for breast conserving surgery. Premenopausal status was determined locally with estradiol (E2) levels &gt;54 pg/mL (or &gt;198 pmol/L), measured within 14 days prior to randomization. Pts were randomized 1:1 to Triptorelin (T) 3.75 mg i.m. on day 1 of every cycle or Degarelix (D) 240 mg s.c. given as two injections of 120 mg on day 1 of cycle 1, then 80 mg s.c. on day 1 of cycles 2-6 with letrozole (L) 2.5 mg/day for 6 cycles. Each cycle was 28 days. Definitive surgery was performed within 2-3 weeks after the last administration of T or D. Serum was collected prior to the first injection (baseline), 24 and 72 hours, 7 and 14 days, then prior to injection on day 1 of cycles 2-6. The primary endpoint was time to optimal ovarian function suppression (OFS) calculated as time from the first injection of D or T to the first assessment of centrally assessed 17-β-estradiol (E2) level in the range of optimal OFS (≤2.72 pg/mL or ≤10 pmol/L) during the 6 cycles of NET. The trial had 90% power to detect a difference using a logrank test, 2-sided α=0.05. Secondary endpoints included tolerability, Ki67changes, PEPI score, best overall response. NCT02005887

Results: TREND completed accrual of 51 pts in January 2017. A preliminary analysis based on the first 45 pts is reported here. 89% of patients were ≥40 yrs, 76% had T1-2 and 22% T3 tumors, and 51% were node-positive. Dominant histology type was ductal (93%). The table summarizes centrally-assessed E2 according to treatment at baseline and for the first 5 assessment time points indicating immediate suppression for the D+L arm. E2 levels on day 1 of cycles 2-6 were all below the limit of quantification (0.625 pg/mL) for the D+L arm. For the T+L arm continued OFS was not maintained in 4 pts.

 BaselineCycle 1Cycle 2Day:01371429No. Pts      D+L222221212221T+L232321232222Median (IQR)     D+L96.2 (64.2,206.8)10.1 (4.0,21.8)0.6 (0.6,1.0)0.6 (0.6,0.6)0.6 (0.6,0.6)0.6 (0.6, 0.6)T+L85.1 (49.7,118.0)37.4 (17.9,59.2)12.8 (7.7,23.8)9.0 (1.2,29.7)0.6 (0.6,1.4)0.6 (0.6, 0.6)

Conclusion: Evidence from this first analysis demonstrates rapid and maintained OFS with the combination of D+L as a NET in premenopausal breast cancer patients. The final analysis of the total population, including secondary endpoints, will be presented at the symposium.

Citation Format: Colleoni M, Gray K, Munzone E, Dellapasqua S, Zamagni C, Gianni L, Johansson H, Viale G, Kammler R, Maibach R, Rabaglio-Poretti M, Di Leo A, Coates AS, Gelber RD, Regan MM, Goldhirsch A. A randomized phase II trial evaluating the endocrine activity and efficacy of neoadjuvant degarelix versus triptorelin in premenopausal patients receiving letrozole for primary endocrine responsive breast cancer (TREND; IBCSG 41-13) [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 P1-10-06.

Abstract P5-18-01: Extended continuous vs intermittent adjuvant letrozole in postmenopausal women with lymph node-positive, early breast cancer (IBCSG 37-05/BIG 1-07 SOLE): Impact on patient-reported symptoms and quality of life

Background: SOLE efficacy results presented at ASCO 2017 showed that extended intermittent vs continuous letrozole for 5 years did not improve disease-free survival in postmenopausal women who had received 4-6 years of adjuvant endocrine therapy for hormone-receptor positive (HR+), lymph-node positive breast cancer. Previous studies showed that the burden by symptoms related to endocrine therapy can be substantial. Even if symptoms improve during the treatment course, extending treatment implies continuation of symptoms. We compared differences in patient-reported symptoms (PRS) and quality of life (QoL) between extended continuous and intermittent letrozole over the first two years of trial treatment.

Methods: From Nov 2007 to Dec 2010, 956 postmenopausal women who were disease-free following 4-6 years of prior adjuvant endocrine therapy for HR+, node-positive breast cancer were enrolled in the QoL substudy of the randomized phase III trial SOLE at selected centers. Patients receive extended continuous letrozole (2.5 mg daily) for 5 years or intermittent letrozole, taken for the first 9 months of years 1-4, and 12 months in year 5. 955 patients completed the 18-item Breast Cancer Prevention Trial (BCPT) Symptom Scales and further symptom-specific and global QoL indicators at baseline, and at 6, 12, 18 and 24 months after randomization. Differences in change of PRS and QoL from baseline between the two administration schedules were tested at 12 and 24 months for 8 symptom scales, 4 additional symptom and 4 global QoL indicators using mixed models with repeated measures.

Results: Small changes in PRS and QoL scores were observed between baseline and 12 months after randomization, i.e. at the end of the first treatment-free interval in the intermittent arm. These changes showed a consistent pattern of greater worsening for patients receiving continuous compared to patients receiving intermittent letrozole. Patients receiving continuous letrozole reported a significantly greater worsening in vaginal problems (p&lt;.02), musculoskeletal pain (p&lt;.03), sleep disturbance (p&lt;.01), physical wellbeing (p&lt;.01) and mood (p&lt;.03). At 24 months (after 2nd treatment-free interval) patients with intermittent letrozole reported a greater improvement in hot flushes (p&lt;.03) than those with continuous letrozole. Changes in the other outcomes did not significantly differ between arms at 24 months.

Conclusion: Although changes in PRS and QoL were small, there was a consistent pattern favoring the intermittent arm. For several symptoms and global QoL indicators, significantly less worsening was observed with the intermittent administration, mainly during the first year of extended treatment, due to small improvements during the treatment-free interval. Froma QoL perspective, women who suffer from endocrine side-effects in the extended setting may benefit from an intermittent administration.

Citation Format: Ribi K, Luo W, Colleoni M, Karlsson P, Chirgwin J, Aebi S, Jerusalem G, Neven P, Di Lauro V, Gomez HL, Ruhstaller T, Abdi E, Di Leo A, Müller B, Maibach R, Gelber RD, Goldhirsch A, Coates AS, Regan MM, Bernhard J. Extended continuous vs intermittent adjuvant letrozole in postmenopausal women with lymph node-positive, early breast cancer (IBCSG 37-05/BIG 1-07 SOLE): Impact on patient-reported symptoms and quality of life [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-18-01.

Abstract P5-18-02: Nab-Paclitaxel-based therapy in the first line treatment of metastatic breast cancer (IBCSG 42-12/BIG 2-12 SNAP): Impact of different schedules on quality of life

Background: The randomized phase II SNAP trial assessed three alternative reduced maintenance chemotherapy regimens using nab-Paclitaxel after a short term induction phase at conventional doses as first line treatment in patients (pts) with metastatic breast cancer (MBC). For all three regimens median progression-free survival was greater than achieved with full dose docetaxel (historical reference). Symptom palliation and quality of life (QoL) are important when deciding on therapeutic agents and schedules in MBC pts.

Methods: Of the 258 pts with MBC enrolled from April 2013 to August 2015 in the SNAP trial, 255 were included in the QoL analysis. Pts were randomized to three arms, each receiving the same induction chemotherapy based on 3 cycles of nab-Paclitaxel 150 mg/m2 dd 1, 8, 15 Q28, which was reduced to 125 mg/m2 after a safety review. The schedules of nab-Paclitaxel in maintenance therapy differed in each arm: Arm A) 150 mg/m2 dd 1,15 Q28; Arm B) 100 mg/m2 dd 1,8,15 Q28; Arm C) 75 mg/m2 dd 1,8,15,22 Q28. Pts completed a QoL form to assess global and symptom-specific indicators (range 0-100) at baseline, and at day 1 of every cycle for the first 12 cycles on treatment, or until treatment discontinuation. Changes in QoL scores during induction (day 1 cycle 4 − baseline) and maintenance (day 1 cycle 12 – day 1 cycle 4) therapy were summarized descriptively per arm. Treatment effects on changes in QoL during maintenance therapy were analyzed by repeated measurement models including timepoints (from day 1 of cycle 4 to day 1 of cycle 12), induction start dose, age, and treatment arms as covariates.

Results: During induction therapy, mean changes [SD] in hair loss (Arm A:−70.2 [41.9]; Arm B: −77.3 [34.5]; Arm C: −72.6 [32.8]), sensory neuropathy (Arm A: −19.0 [25.2]; Arm B: −20.6 [22.7]; Arm C: −18.8 [23.8]), and treatment burden (Arm A: −12.9 [33.4]; Arm B: −13.4 [33.5]; Arm C: −11.4 [34.8]) showed the most pronounced worsening. During maintenance therapy, scores for sensory neuropathy remained impaired without worsening. No significant differences in changes for sensory neuropathy or the other symptoms were seen between arms, except for hair loss, with pts in arm C (mean difference 10.91; 95% CI [0.35, 21.48]; p=0.04) ] and B (mean difference 18.55; 95% CI [7.52, 29.59]; p=0.001) reporting a greater improvement compared to those in arm A. Pts in arm C reported a significantly greater improvement in mood compared to arm A (mean difference 13.34; 95% CI [6.08, 20.60]; p&lt;0.001) and arm B (mean difference 9.62; 95% CI [2.84, 16.40]; p=0.01)].

Conclusion: The effectiveness of alternative maintenance chemotherapy schedules with reduced doses after a short term induction phase at conventional doses must be weighed against a substantial worsening in sensory neuropathy during induction therapy, and scores continuing to be impaired without worsening with prolonged administration. During maintenance therapy, improvements were seen in the perception of hair loss and in mood, particularly in Arm B and C, with a similar tendency seen for some other QoL domains. A more frequent administration of reduced dose chemotherapy agents is favorable with respect to QoL in this setting.

Citation Format: Ribi K, Sun Z, Jerusalem G, Hasler-Strub U, Colleoni M, von Moos R, Cortés J, Vidal M, Hennessy B, Walshe J, Amillano Parraga K, Morales Muriilo S, Pagani O, Barbeaux A, Bortsnar S, Maibach R, Regan MM, Gennari A, Bernhard J. Nab-Paclitaxel-based therapy in the first line treatment of metastatic breast cancer (IBCSG 42-12/BIG 2-12 SNAP): Impact of different schedules on quality of life [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-18-02.

Abstract GS6-01: Integration of clinical variables for the prediction of late distant recurrence in patients with oestrogen receptor positive breast cancer treated with 5 years of endocrine therapy

Background: The prediction of late distant recurrence (DR) is an important clinical goal for managing women with hormone receptor positive disease who have reached the end of 5 years' endocrine treatment without recurrence. Molecular profiles have produced conflicting results for the prediction of late DR. Here, we develop and validate a simple clinicopathological tool (Clinical Treatment Score post-5 years (CTS5)) to estimate the residual risk of DR after 5 years' endocrine treatment, which should help in discussions with patients about the potential benefits or not of continued endocrine therapy.

Patients and Methods: The ATAC dataset (N=4735) of postmenopausal women with oestrogen receptor (ER) positive breast cancer treated with 5 years' tamoxifen or anastrozole was used as a training cohort to establish a prognostic score for post-5-year risk of DR. CTS5 was based on five categories for nodal status, linear and quadratic terms for tumour size (capped at 30mm), three categories for grade, and continuous age. The validity of the CTS5 was tested in the BIG1-98 dataset (N=6711), which included postmenopausal women with ER-positive breast cancer treated with tamoxifen or letrozole (either monotherapy or sequential). Both cohorts included women who were alive and DR-free 5 years after randomization. Time to late DR, defined beginning at 5 years after ATAC or BIG 1-98 randomization, was the primary endpoint. Cox regression models estimated the prognostic performance of the CTS5. Hazard Ratios (HRs) are for a change of one Standard Deviation.

Results: The CTS5 model was a significant predictor for late DR in ATAC (HR=2.47 (95% CI, 2.24-2.73), P&lt;0.001) and performed better than the established 0-10 year CTS model (Cuzick et al., JCO, 2011). CTS5 was confirmed as highly predictive for late DR in the BIG1-98 validation cohort (HR=2.07 (1.88-2.28), P&lt;0.001). Of greatest importance was that CTS5 risk stratification defined in the training cohort as low (&lt;5% risk of DR during years 5-10), intermediate (5-10% risk), high (&gt;10% risk), identified 43% of the validation cohort as low risk, with an observed DR rate of 3.6% (95% CI 2.7-4.9) during years 5-10. Within nodal subgroups, 63% of node-negative were low risk with 3.9% (2.9-5.3) DR rate between years 5-10, and 24% having 1-3 nodes positive were low risk with 1.5% (0.5-3.8) DR rate between years 5-10. Separation of intermediate-risk from high-risk categories was also shown in the training set but improvements in calibration seem necessary for clinical utility for that assessment.

Conclusion: The CTS5 is a simple tool based on information that is readily available to all clinicians. It was more accurate in its prediction of DR risk in years 5-10 than the published CTS model. CTS5 was validated as highly prognostic for late DR in the independent BIG 1-98 study. The algorithm identified a subgroup of women with either node-negative disease or 1-3 positive nodes as having less than 1% per year risk of DR who could be advised of the limited value of extended endocrine therapy.

Citation Format: Sestak I, Regan M, Dodson A, Viale G, Thürlimann B, Colleoni M, Cuzick J, Dowsett M. Integration of clinical variables for the prediction of late distant recurrence in patients with oestrogen receptor positive breast cancer treated with 5 years of endocrine therapy [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 GS6-01.

Abstract OT3-05-01: TBCRC 039: Phase II study of combination ruxolitinib (INCB018424) with preoperative chemotherapy for triple negative inflammatory breast cancer

Background: Stage III triple negative(TN) inflammatory breast cancer(IBC) is associated with a poor prognosis evidenced by a 15 month(mo) median disease free survival(DFS) and overall survival(OS) of 34 mo. The substantial incidence of developing distant metastasis may be due to the prevalence of cancer cells with stem cell-like features (e.g. CD44+/CD24-) in TNIBC. The transcriptional pathway JAK2/STAT3 is associated with the survival of CD44+/CD24- cells, and preclinical data demonstrates overexpression of activated STAT3(pSTAT3) in &gt; 95% of TNIBC. Preclinical studies have shown that ruxolitinib (Incyte®Corporation), an approved JAK1/JAK2 inhibitor, suppresses pSTAT3 in IBC patient derived xenograft models, and when combined with paclitaxel, results in a synergistic reduction in tumor weight. Given the lack of a known therapeutic target in TNIBC, this preoperative proof of principle study exploits the survival mechanism of CD44+/CD24- stem cells prevalent in this disease, by combining ruxolitinib(Rux) with paclitaxel(T) followed by doxorubicin/cyclophosphamide(AC).

Methods: Up to 64 pts with newly diagnosed stage III TNIBC (cT4d, any N, M0) are eligible if they have adequate organ function and are willing to undergo 2 research biopsies(rbx) of the affected breast. Following baseline rbx, pts are randomized to a 7 day(d) run-in phase of Rux vs Rux(15 mg bid) + T(80mg/m2/wkx1). A 2nd rbx is obtained after the run-in phase. Pts randomized to RuxT continue to receive a total of Tx12 wks+Rux. Pts randomized to Rux alone, are re-randomized to receive Tx12 wks+Rux vs Tx12wks alone. Following T, all pts receive AC (A-60mg/m2,C-600mg/m2) every 14d x 4. Pts proceed to modified radical mastectomy (MRM) followed by chest wall/regional lymph nodes radiation therapy.

Correlatives: To assess the effect of JAK inhibition with Rux on pSTAT3 and STAT3 related gene expression, molecular and genomic markers (e.g. RNA-seq, ChIPseq, FISH) will be determined in each rbx and residual tumor at MRM. The relative frequency and topology of CD44+/CD24- cell population and pSTAT3 expression by IHC will also be assessed in these tumor specimens. IL-6 and CRP plasma concentrations will be measured at baseline, prior to T and AC and prior to MRM.

Statistics: The primary endpoint is change in markers of JAK/STAT inhibition. If the proportion of rbx exhibit a biologic response to Rux alone (i.e. change from pSTAT3 expression to pSTAT3 negative) is &lt;10%, then Rux alone is minimally effective on JAK inhibition vs alternative hypothesis that Rux inhibits JAK if the proportion of biologic response is ≥33%. If ≥5/25 rbx treated with Rux alone have a biologic response then the hypothesis that biologic response is ≤10% is rejected with an error rate of 0.098 (target 0.10). If ≤4/25 rbx have a biologic response then the hypothesis that biologic response is ≥33% is rejected with an error rate of 0.05 (target 0.10). Biologic response of rbx with Rux alone will also be compared with the proportion of biologic response to RuxT (33% vs. 66% based upon presumed synergy with RuxT). Secondary endpoints are clinical: pathologic complete response in breast/lymph nodes, Residual Cancer Burden, DFS and OS. Clinical Trial Information: NCT02876302.

Citation Format: Overmoyer B, Regan M, Polyak K, Brock J, Van Poznak C, King T, Haddad T, Stearns V, Hwang S, Winer E. TBCRC 039: Phase II study of combination ruxolitinib (INCB018424) with preoperative chemotherapy for triple negative inflammatory breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT3-05-01.

Abstract GS4-03: Randomized comparison of adjuvant tamoxifen (T) plus ovarian function suppression (OFS) versus tamoxifen in premenopausal women with hormone receptor-positive (HR+) early breast cancer (BC): Update of the SOFT trial

Background: The primary results of SOFT at 5.6 years median follow-up found adding OFS to T did not provide a significant benefit in the overall study population of premenopausal women with HR+ BC (Francis et al, NEJM 2015). For those women at sufficient risk for recurrence to warrant adjuvant chemotherapy (CT) and who remained premenopausal, the addition of OFS improved disease outcomes. Follow-up was immature for overall survival (OS). We report a planned update with visit cut-off of 31Dec16 after 8 yrs median follow-up.

Methods: SOFT randomized premenopausal women with HR+ BC from Nov 2003 to Jan 2011 to 5 yrs of T vs T+OFS vs Exemestane(E)+OFS. OFS was by choice of GnRH agonist triptorelin, oophorectomy or ovarian irradiation. SOFT was stratified by the use of prior CT; 47% received no CT and 53% remained premenopausal after prior CT, determined by premenopausal estradiol level within 8 months of CT completion. The primary endpoint was invasive disease-free survival (DFS; randomization until invasive local, regional, distant recurrence or contralateral breast; invasive second malignancy; death). Secondary endpoints included invasive breast cancer-free interval (BCFI), distant recurrence-free interval (DRFI) and OS. NCT00066690.

Results: DFS for patients assigned T+OFS (n=1015) was significantly improved over T (n=1018; HR=0.76 [95%CI 0.62-0.93]) and 8yr DFS was 83.2% vs 78.9%, respectively; BCFI and DRFI results were supportive (see Table). Hazard ratios for these 3 endpoints showed no heterogeneity by use of prior CT. For patients with prior CT, 8yr DFS was 76.7% with T+OFS vs 71.4% with T (Δ=5.3%); in those without CT, 8yr DFS was 90.6% vs 87.4% (Δ=3.2%). E+OFS (n=1014) improved outcomes relative to T (Table); 8yr DFS for E+OFS was 85.9% (80.4% with use of prior CT and 92.5% for those without CT). OS was improved with T+OFS vs T (8yr OS 93.3% vs 91.5%). 8yr OS was 92.1% with E+OFS. 201/225 deaths occurred in women with prior CT. For women without CT there have been 10, 5 and 9 deaths in the T+OFS, T and E+OFS groups (total n=1419), respectively, only half of these deaths after breast cancer event.

N. EventsHazard Ratio (95% CI)Endpoint(3 arms)T+OFS vs TE+OFS vs TDFS5180.76 (0.62-0.93) P=0.0090.65 (0.53-0.81)BCFI4370.76 (0.61-0.95)0.64 (0.51-0.81)DRFI3060.86 (0.66-1.13)0.73 (0.55-0.96)OS2250.67 (0.48-0.92)0.85 (0.62-1.15)

Overall toxicity was worse with T+ OFS than with T, including 32% vs 25% grade 3+ targeted AEs. Early cessation of tamoxifen occurred for 19% assigned T+OFS and 22% of women assigned T; the cumulative incidence of early cessation of triptorelin on the T+OFS arm was 23% by 4yrs. Early cessation of exemestane occurred for 28% and of triptorelin for 21% by 4yrs on the E+OFS arm.

Conclusions: With additional follow-up to a median of 8yrs, SOFT further supports the value of OFS for some premenopausal women. Follow-up continues, which will further clarify the safety and the benefit of OFS for late recurrence and overall survival. Oncologists appear to be able to select a low risk group (no chemotherapy) for whom treatment escalation is unlikely to improve survival.

Citation Format: Fleming G, Francis PA, Láng I, Ciruelos EM, Bellet M, Bonnefoi HR, Climent MA, Pavesi L, Burstein HJ, Martino S, Davidson NE, Geyer Jr CE, Walley BA, Coleman RE, Kerbrat P, Buchholz S, Ingle JN, Rabaglio-Poretti M, Colleoni M, Regan MM. Randomized comparison of adjuvant tamoxifen (T) plus ovarian function suppression (OFS) versus tamoxifen in premenopausal women with hormone receptor-positive (HR+) early breast cancer (BC): Update of the SOFT trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr GS4-03.

Abstract GS5-02: Axillary dissection vs. no axillary dissection in patients with cT1-T2cN0M0 breast cancer and only micrometastases in the sentinel node(s): Ten-year results of the IBCSG 23-01 trial

BACKGROUND: The phase III IBCSG 23-01 multicenter, randomized, non-inferiority trial compared disease-free survival (DFS) in breast cancer patients with one or more micrometastatic (≤2 mm) sentinel nodes (SNs) randomized to either axillary dissection (AD) or no axillary dissection (no-AD). Results after 5 years showed no difference in DFS between the arms. Here we report results after a median follow-up of 9.8 years.

METHODS: Eligible patients had cancers of pathological diameter ≤5 cm and one or more micrometastatic (≤2 mm) foci, including isolated tumor cells, in the SNs. Patients with axillary macrometastases were excluded. Breast surgery was conservative or mastectomy. Eligible patients were randomized to AD vs. no-AD. The primary endpoint was disease-free survival (DFS); secondary endpoints were overall survival (OS), site of recurrence (particularly axillary recurrence), and surgical complications of AD. DFS and OS were estimated using the product-limit method, and the log-rank test was used to compare the treatment groups. Patients without a DFS or OS event were censored at the date of last follow-up. Non-inferiority margin for no-AD vs. AD was defined as a DFS hazard ratio (HR, no-AD relative to AD) of &lt;1.25, and was assessed using a z-test applied to the log HR. Active follow-up of patients was terminated in February 2017.

RESULTS: From 2001 to 2010, 934 patients were randomized at 27 centers; 931 were evaluable (467 in the no-AD group and 464 in the AD group). Median follow-up was 9.8 (IQR: 7.8–12.7) years. The number and types of first DFS events according to treatment group are shown in the Table.

Disease-free Survival EventsNo-ADADTotal101117Breast cancer related events7475Local1413Contralateral breast1012Regional [ipsilateral axillary events]9 [8]3 [2]Distant4147Non-breast cancer related events2742Second malignancies1723Death without prior cancer event62Death with unknown cancer status417

10-year DFS was 75% (95% confidence interval [CI]: 72%–81%) in the no-AD group and 75% (95% CI: 71%–79%) in the AD group (HR [no-AD vs. AD]=0.85; 95% CI: 0.65–1.11; log-rank p=0.23; non-inferiority p=0.002). There were 45 deaths in the no-AD group and 58 in the AD group. 10-year OS was 91% (95% CI: 88%–94%) in the no-AD group and 88% (95% CI: 85%–92%) in the AD group (HR [no-AD vs. AD]=0.77; 95% CI: 0.56–1.07; log-rank p=0.19).

CONCLUSION: Findings after a median follow-up of 9.8 years fully support the findings at 5 years in that no-AD is not inferior to AD with respect to DFS, and there is no significant difference between the arms for DFS and OS, thus confirming that AD is not indicated in patients with micrometastatic SNs.

Citation Format: Galimberti V, Cole BF, Viale G, Veronesi P, Vicini E, Intra M, Mazzarol G, Massarut S, Zgajnar J, Taffurelli M, Littlejohn D, Egli T, Tondini C, Di Leo A, Colleoni M, Regan MM, Coates AS, Gelber RD, Goldhirsch A. Axillary dissection vs. no axillary dissection in patients with cT1-T2cN0M0 breast cancer and only micrometastases in the sentinel node(s): Ten-year results of the IBCSG 23-01 trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr GS5-02.

De-escalating and escalating treatments for early-stage breast cancer: the St. Gallen International Expert Consensus Conference on the Primary Therapy of Early Breast Cancer 2017

The 15th St. Gallen International Breast Cancer Conference 2017 in Vienna, Austria reviewed substantial new evidence on loco-regional and systemic therapies for early breast cancer. Treatments were assessed in light of their intensity, duration and side-effects, seeking where appropriate to escalate or de-escalate therapies based on likely benefits as predicted by tumor stage and tumor biology. The Panel favored several interventions that may reduce surgical morbidity, including acceptance of 2 mm margins for DCIS, the resection of residual cancer (but not baseline extent of cancer) in women undergoing neoadjuvant therapy, acceptance of sentinel node biopsy following neoadjuvant treatment of many patients, and the preference for neoadjuvant therapy in HER2 positive and triple-negative, stage II and III breast cancer. The Panel favored escalating radiation therapy with regional nodal irradiation in high-risk patients, while encouraging omission of boost in low-risk patients. The Panel endorsed gene expression signatures that permit avoidance of chemotherapy in many patients with ER positive breast cancer. For women with higher risk tumors, the Panel escalated recommendations for adjuvant endocrine treatment to include ovarian suppression in premenopausal women, and extended therapy for postmenopausal women. However, low-risk patients can avoid these treatments. Finally, the Panel recommended bisphosphonate use in postmenopausal women to prevent breast cancer recurrence. The Panel recognized that recommendations are not intended for all patients, but rather to address the clinical needs of the majority of common presentations. Individualization of adjuvant therapy means adjusting to the tumor characteristics, patient comorbidities and preferences, and managing constraints of treatment cost and access that may affect care in both the developed and developing world.

Abstract P2-09-09: The effects of treatment-induced symptoms, depression and age on sexuality in premenopausal women with early breast cancer receiving adjuvant endocrine therapy

Background: In premenopausal women with breast cancer any treatment that causes abrupt, premature ovarian failure increases the risk of sexual problems. Randomized-controlled trials in this population reported a worsening in sexual functioning over time irrespective of adjuvant endocrine treatment. We investigated key symptoms related to endocrine therapy, depression and age as predictors of sexual problems in premenopausal women with early breast cancer treated in the IBCSG TEXT/SOFT trials over the first two years of endocrine therapy.

Methods: A subset of patients (pts) enrolled by centers with English as primary language to TEXT (1027 of 2672 pts) and SOFT (1260 of 3066 pts) completed a questionnaire consisting of global and symptom-specific quality of life indicators, the CES-Depression (CES-D) and the MOS- Sexual Problems (MOS-SP) measures at baseline, 6, 12 and 24 months. The analysis considered 5 cohorts of pts according to chemotherapy use (yes/no), trial (SOFT/TEXT) and endocrine treatment assignment (tamoxifen alone [T], T or exemestane [E] with ovarian function suppression [OFS]). Mixed modeling was used to test the effect of the following on changes in sexual problems (MOS-SP total score) over two years: changes in treatment-induced symptoms (hot flushes, vaginal dryness, sleep disturbances, bone/joint pain, troubled by weight gain, tiredness, nausea/vomiting) from baseline to 6 months; depression at 6 months; and age at randomization. The model included severity groups of symptoms, depression (all dichotomized by median) and age (&lt; 40 vs ≥40 years), 5 cohorts, time points (6, 12, 24 months), baseline covariates, and interactions of symptoms, timepoints and cohorts.

Results: Overall across cohorts, pts with more severe worsening of vaginal dryness and sleep disturbances at 6 months reported a greater increase in sexual problems at all timepoints (p&lt;.0001). The effect of vaginal dryness on sexual problems was most pronounced in the cohort of pts who received T+OFS or E+OFS without chemotherapy; the effect of sleep disturbances was most pronounced in the cohort with prior chemotherapy and T alone. All other symptoms had a smaller impact on differences in changes of sexual problems. Significant effects were only seen in the short-term and varied according to cohort. Severity of depression at six months did not predict sexual problems at the later timepoints in the overall population. In the cohort that received T+OFS or E+OFS without chemotherapy, pts who had more severe depression scores at 6 months reported significantly worse sexual problems at all timepoints (p&lt;.05). No differences were found for younger vs. older pts with respect to sexual problems at any timepoint.

Conclusion: Among several key symptoms related to endocrine therapy, only vaginal dryness and sleep disturbances significantly predicted sexual problems during the first two years in pts who received adjuvant endocrine therapy with or without chemotherapy. Depression predicted sexual problems only in the cohort of pts who received combined endocrine treatment without chemotherapy. Early identification of vaginal dryness, sleep disturbances and depression is important for timely and tailored interventions.

Citation Format: Ribi K, Luo W, Burstein HJ, Naughton MJ, Chirgwin J, Ansari RH, Walley BA, Salim M, van der Westhuizen A, Abdi E, Francis PA, Budman DR, Kennecke H, Harvey VJ, Giobbie-Hurder A, Fleming GF, Pagani O, Regan MM, Bernhard J. The effects of treatment-induced symptoms, depression and age on sexuality in premenopausal women with early breast cancer receiving adjuvant endocrine therapy [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 P2-09-09.

Abstract OT1-01-07: A phase 2 study of eribulin followed by doxorubicin and cyclophosphamide as preoperative therapy for HER2-negative inflammatory breast cancer

Background: HER2 negative(neg) inflammatory breast cancer(IBC) exhibits relative resistance to chemotherapy evidenced by pCR(pathologic complete response rate) rates of 12-25% with preoperative taxane/anthracycline regimens. Eribulin(Eisai®) inhibits microtubular function via sequestration of tubulin into nonfunctional aggregates, thus being effective against taxane-resistant cancer. Preclinical data shows 2 mechanisms of action: reversion of EMT(epithelial to mesenchymal transition) and normalization of tumor vascularity. Treatment of triple negative breast cancer(TNBC) cell-lines with eribulin results in downregulation of mesenchymal markers with concomitant increase in expression of classical epithelial markers(Yoshida BJC 2014). In PDX models, eribulin improved blood perfusion in central region of tumors, increased vessel density, reduced vessel diameter, and reduced hypoxia. IBC is highly angiogenic, with increased microvessel density, higher fraction of proliferating endothelial cells and greater expression of pro-angiogenic genes compared with non-IBC(McCarthy CCR 2002). This preoperative study(EAC) exploits the angiogenic properties of IBC with the treatment scheme of eribulin(E) followed by doxorubicin/cyclosphosphamide(AC) in newly diagnosed HER2neg IBC.

Methods: Pts with HER2neg Stage III (cT4d,any N,M0) IBC are eligible if they have not received prior therapy for BC, have adequate organ function, cardiac ejection fraction &gt; 50%, and willing to undergo 2 research biopsies (rbx) of the affected breast. Following baseline rbx, pts receive cycle 1, day(d)1 eribulin 1.4 mg/m2. A 2nd rbx occurs on d8, prior to dosing of E. Following 3 more cycles of E(1.4mg/m2 d1,d8,every 21d), pts receive 4 cycles of dose-dense AC(A-60 mg/m2,C-600mg/m2 every 14d). Pts with adequate disease response undergo mastectomy/axillary lymph node dissection followed by chest wall/regional lymph node radiation. Adjuvant endocrine therapy is used if hormone receptor positive. An imaging sub-study evaluates tumor perfusion via DCE-MRI pre and post 1st dose E.

Correlatives: To investigate whether E induces reversion of EMT in IBC, expression of 10 EMT-related genes are determined in each rbx, and normalization of tumor vessel phenotype are assessed by expression of 15 angiogenesis-related genes in rbx by RT-qPCR. Gene expression will be repeated on residual tumor at mastectomy. An imaging sub-study of DCE-MRI (10 pts) will assess vascular remodeling via changes in Ktrans , ve and vp determination of IBC region of interest, core and rim and changes in the iAUC computed pre and post 1st dose E.

Statistics: The primary endpoint is pCR. A Simon two-stage design is used. If the proportion of pts having pCR is &lt; 0.10 then EAC is considered minimally effective, versus alternative hypothesis that EAC is worthy of further study if proportion pCR &gt; 0.30. In the 1st stage, if &lt; 2/16 pts have pCR, the study is stopped; if &gt; 3 pts have pCR, the study proceeds. In the 2nd stage, EAC is rejected if &lt; 4 of 25 pts have a pCR(α=0.10;β=0.10). Up to 25 pts will be enrolled. Secondary endpoints are residual cancer burden, disease-free survival, time to treatment failure and overall survival. Clinical trial information: NCT02623972.

Citation Format: Overmoyer B, Goel S, Regan M, Hirshfield-Bartek J, Schlosnagel E, Yeh E, Qin L, Bellon J, Nakhlis F, Jacene H, Winer E. A phase 2 study of eribulin followed by doxorubicin and cyclophosphamide as preoperative therapy for HER2-negative inflammatory breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT1-01-07.

Abstract P4-12-01: Independent validation of EarlyR gene signature in BIG 1-98: A randomized, double-blind, phase III trial comparing letrozole and tamoxifen as adjuvant endocrine therapy for postmenopausal women with hormone receptor-positive, early breast cancer

Background: EarlyR is a prognostic gene signature score in ER+ breast cancer (BC) computed from the expression values of ESPL1, SPAG5, MKI67, PLK1 and PGR using a novel algorithm. EarlyR has been validated in multiple cohorts profiled on Affymetrix and Illumina microarrays. This study sought to verify prognostic features of EarlyR in a cohort of BIG 1-98.

Patients and Methods: Illumina DASL assay was used to measure gene expression in FFPE tissue of primary BC from a case-cohort sampling subset of postmenopausal women in BIG 1-98 treated with adjuvant endocrine therapy (letrozole or tamoxifen). Chemotherapy treatment was at the discretion of individual physicians and patients. Among the 1218 patients centrally reviewed with sufficient RNA material for the DASL assay, 1174 with ER+ status and assessed for EarlyR are included in the analytic cohort. EarlyR scores and pre-specified risk strata (≤25=low, 26-75=intermediate, &gt;75=high) were computed, while blinded to clinical data. The analysis endpoints included distant recurrence free interval (DRFI) defined as time from randomization to BC recurrence at a distant site within 8 years and BC free-interval (BCFI) defined as time from randomization to first invasive BC recurrence at a local, regional or distant site or invasive contralateral BC within 8 years. Weighted proportional hazards models (univariate and multivariate, stratified by treatment assignment) were used to adjust for Kaplan-Meier, hazard ratio estimates and Wald test statistics to obtain unbiased analyses and to give consistent estimates.

Results: The distribution of the EarlyR risk groups was 67% low, 19% intermediate and 14% high risk in this ER+ cohort. EarlyR was prognostic for 8-year DRFI (P-trend=0.008). Patients with high EarlyR risk score (&gt;75) had significantly increased risk of distant recurrence within 8 years (univariate HR=1.73, 95%CI: 1.14-2.64) compared to low EarlyR risk group (≤25). The estimated 8-year DRFI (95%CI) is 84%(80%-88%) for high risk vs. 91%( 89%-92%) for low risk, corresponding to an absolute DRFI risk reduction of 7% (low vs high). EarlyR is also prognostic of 8-year BCFI in ER+ (P-trend=0.002) with the estimated 8-year BCFI (95%CI) 79%(75%-84%) for high risk vs. 88%( 86%-89%) for low risk. Consistent results were observed in ER+, HER2- (P-trend=0.01 for DRFI, P-trend=0.004 for BCFI), in ER+, LN- (P-trend=0.05 for DRFI, P-trend=0.03 for BCFI) and ER+, LN+ (P-trend=0.08 for DRFI, P-trend=0.03 for BCFI) subsets.

Conclusions: This study confirmed the prognostic significance of EarlyR using FFPE tissue from the BIG 1-98 trial. In analyses of all ER+ patients and subsets LN-, LN+ and HER2-, EarlyR classifies 65%-70% of patients as low risk, 11-16% as high risk, and &lt; 20% as intermediate risk. In these subsets, the size of the low risk group is larger and the size of the intermediate risk group is smaller than those reported for commercially available signatures. EarlyR identifies a set of high-risk patients with relatively poor prognosis who may be considered for additional treatment. The clinical utility of EarlyR requires further study.

Citation Format: Buechler S, Gray KP, Gökmen-Polar Y, Willis S, Thürlimann B, Kammler R, Leyland-Jones B, Badve SS, Regan MM. Independent validation of EarlyR gene signature in BIG 1-98: A randomized, double-blind, phase III trial comparing letrozole and tamoxifen as adjuvant endocrine therapy for postmenopausal women with hormone receptor-positive, early breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-12-01.

Abstract OT3-02-03: Long-term follow-up of TEXT and SOFT trials of adjuvant endocrine therapies for premenopausal women with HR+ early breast cancer

Background

First results of the TEXT and SOFT international phase III trials were practice-changing, indicating that: i) 5y adjuvant exemestane+ovarian function suppression (E+OFS) reduces recurrence risk relative to tamoxifen(T)+OFS or to T alone, ii) T+OFS reduces recurrence risk vs T in women who are at sufficient risk to warrant chemotherapy (CT) and remain premenopausal afterwards, and iii) T alone remains appropriate for some premenopausal women. However, median follow-up (FU) was only 5.5y and &lt;5% pts had died. FU is immature given the long natural history of HR+ disease and EBCTCG overviews showing overall survival (OS) improvements for T vs no-T emerged during 5-15y. It is crucial to establish if changing standard adjuvant endocrine therapy from T improves survival and if there are associated late toxicities.

Trial Design and Aims

Premenopausal women had invasive early breast cancer (BC) assessed as ≥10% ER and/or PgR.

SOFT was designed to determine the value of adding OFS to T, and the role of E+OFS in two cohorts: women who remained premenopausal after completion of neo/adjuvant CT, and women for whom adjuvant T alone was considered suitable treatment. SOFT compares 5y of T to T+OFS or E+OFS. OFS was GnRH analog triptorelin x5y, oophorectomy or ovarian irradiation. Median age was 43y; 35% had N+ disease. 53% enrolled after prior neo/adjuvant CT.

TEXT was designed to determine the role of adjuvant E in premenopausal women receiving OFS from the start of adjuvant therapy, comparing 5y of E+OFS vs T+OFS. Patients enrolled at start of all adjuvant therapy; 60% had CT concurrent with triptorelin after entry. Median age was 43y; 48% had N+ disease.

Secondary objectives include effects on OS, late side effects of early menopause and late toxicities.

Accruals

TEXT: 2672 women, Nov03-Mar11

SOFT: 3066 women, Dec03-Jan11

Statistical Methods

The primary endpoint, invasive disease-free survival, is time from randomization to invasive local, regional, or distant relapse, contralateral BC, second non-BC malignancy, or death. Secondary endpoints are BC-free interval, distant recurrence-free interval and OS. Primary results were reported in 2014, after ∼5.5y median FU; 30% pts were still on 5y treatment and &gt;90% continued in FU.

Long-term FU

Updated results are planned for FU through Dec16, with ∼8y median FU. Pts finished 5y treatment by Apr16. Yearly visits continue; data collection includes weight, performance status, menstrual status, pregnancy attempts, GYN procedures, late AEs (cardiovascular, bone fracture), extended adjuvant therapy, invasive recurrence at first and subsequent sites, second non-BC malignancy, in situ cancers, OS.

FU through 2020 is planned, for min and median FU of 10 and 12y, roughly doubling the numbers of endpoints events since the first report. This will be critical to determine whether short-term treatment benefits persist for late recurrence, improve power to detect treatment effects on distant recurrence and OS endpoints with lower event rates occurring later in FU, and define associated late toxicities and side effects of early menopause. A consortium to fund long-term FU is being pursued.

Citation Format: Francis PA, Fleming GF, Regan MM, Pagani O, Walley BA, Price KN, Coates AS, Goldhirsch A, Gelber R. Long-term follow-up of TEXT and SOFT trials of adjuvant endocrine therapies for premenopausal women with HR+ early breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT3-02-03.

Abstract P1-01-01: Circulating tumor cell number and CTC-endocrine therapy index predict clinical outcomes in ER positive metastatic breast cancer patients: Results of the COMETI Phase 2 trial

Introduction: Only half of hormone receptor positive (HR+) metastatic breast cancer (MBC) patients (pts) benefit from endocrine therapy (ET). Circulating tumor cells (CTC) are prognostic in pts with MBC using CellSearch® technology. The CTC-endocrine therapy index (CTC-ETI) provides semi-quantitative analyses of CTC-ER (estrogen receptor), BCL2, HER2, and Ki67 expression. We hypothesized that CTC-ETI high (elevated CTC number and/or low expression of ER and BCL2, and high expression of HER2 and Ki-67) might predict resistance to ET in a prospective, multi-institutional clinical trial: COMETI-P2-2012.0 (NCT01701050).

Methods: 121 pts with ER+, HER2 negative (-), and progressive MBC after one or more lines of ET or within 12 months (mos) of completing adjuvant ET, who were initiating a new ET, were enrolled after informed consent. CTC and CTC-ETI were determined as previously reported (Paoletti C et al, CCR 2015) at baseline (BL), 1, 2, 3, and 12 mos, and/or at the time of progression. Imaging was performed every 3 mos. Association of CTC levels and CTC-ETI with patient outcomes (progression free survival (PFS); rapid progression (RP) defined as progression within 3 mos) was assessed using logrank and Fisher's exact tests. Trial design estimated 85 PFS and 51 RP events, providing &gt;90% power (2-sided a=0.05); pts with unsuccessful BL CTC-ETI or ineligible were unevaluable. Only baseline (BL) data are reported in this abstract.

Results: 32% of enrolled pts had progression within 12 mos of completing adjuvant ET, whereas 40%, 20%, and 8% had 1, 2, ≥3 lines of ET for MBC. CTC-ETI was successfully determined in 93% of pts (90% CI, 88% to 97%). CTC were ≥5 CTC/7.5 ml whole blood in 37/108 (34%) pts evaluable for clinical validity. Elevated CTC was associated with worse PFS (median (m) PFS: 3.3 vs. 5.9 mos; P&lt;0.01). Low, intermediate, and high CTC-ETI were observed in 75 (69%), 6 (6%), and 27 (25%) pts, respectively. CTC-ETI was associated with PFS (logrank P&lt;0.01): pts with low, intermediate, and high CTC-ETI had mPFS of 5.7, 8.5, and 2.8 mos, respectively. In the 96 pts eligible for determination, elevated CTC was associated with RP, (65.6% vs. 42.2%; P=0.05) as was CTC-ETI (P=0.003): 79.2% (95% CI, 57.8% to 92.9%) of pts with high CTC-ETI had RP versus 41.2% (95% CI, 29.4% to 53.8%) with low CTC-ETI; in the small group with intermediate CTC-ETI 1 of 4 pts (25%) had RP.

Conclusions: In this multi-institutional, prospective study, CTC-ETI was accurately determined, confirming the previously established analytical validity of the assay, meeting the primary objective of the trial. Elevated CTC and CTC-ETI high compared to low were associated with poor outcomes to ET. CTC-ETI distribution resulted in a small number of patients assigned to the intermediate group, restricting our ability to associate this group with outcomes. These results suggest that CTC-biomarker phenotype and enumeration have clinical validity. CTC-ETI may identify ER+ HER2– MBC pts who are unlikely to benefit from ET and might be better treated with ET in combination with other therapies or proceed to chemotherapy. Further analyses including CTC-ETI at serial time points during ET are planned.

Citation Format: Paoletti C, Regan MM, Liu MC, Marcom PK, Hart LL, Smith II JW, Tedesco KL, Amir E, Krop IE, DeMichele AM, Goodwin PJ, Block M, Aung K, Cannell EM, Darga EP, Baratta PJ, Brown ME, McCormack RT, Hayes DF. Circulating tumor cell number and CTC-endocrine therapy index predict clinical outcomes in ER positive metastatic breast cancer patients: Results of the COMETI Phase 2 trial [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-01-01.

Abstract P2-09-05: 12 years' median follow up (MFU) of BIG 1-98: Adjuvant letrozole, tamoxifen and their sequence for postmenopausal women with endocrine responsive early breast cancer

Background

The Breast International Group (BIG) 1-98 study is a randomized, phase 3, double-blind trial that compared five yrs of adjuvant treatment with letrozole, tamoxifen, or their sequence in postmenopausal women with hormone-receptor–positive early breast cancer. The study is conducted by the International Breast Cancer Study Group (IBCSG) on behalf of BIG. 8010 patients (pts) were enrolled between March 1998 and May 2003, and first results demonstrating a significant DFS benefit favoring letrozole compared with tamoxifen were reported in 2005 at 25.8 months' MFU. Subsequent updates showed continuing DFS benefit and updated results published in 2011 at 8.1 yrs' MFU showed OS benefit. Industry-sponsorship of the original BIG 1-98 ended in 2010; IBCSG launched an observational, non-interventional long-term follow-up study (BIG 1-98 LTFU) to collect survival, disease status and adverse events for an additional 5 yrs. We report results from BIG 1-98 LTFU at 12 yrs' MFU.

Methods

The original trial includes the 8010 patients enrolled. The potential BIG 1-98 LTFU cohort consisted of 148 academic medical centers with a maximum of 6843 pts who were alive and continuing follow-up when the original study ended. Response bias was addressed using weighting class adjustments estimated using multivariable logistic regression. Unadjusted incidence rates are reported here per 1000 pt-yrs with 95% Poisson confidence intervals. An updated abstract will include adjusted incidence rates, as well as estimates of OS and DFS based on a weighted Kaplan-Meier approach. The database will close in July 2016.

Results

As of May 2016, 81 centers participated in the BIG 1-98 LTFU study, contributing data from approximately 3900 pts (57%) and extending MFU to 12 yrs. Compared with the potential cohort of 6843 pts, the ~3900 in the LTFU analytic cohort were more likely to be under age 65 yrs at enrollment, have node-positive disease, and have tumors that were &lt; 2 cm, PgR positive (≥1%), and with no evidence of peritumoral vascular invasion. Extended adjuvant endocrine therapy for primary BC was continued in 2% of pts. Unadjusted incidence estimates of myocardial infarction increased during LTFU, while incidence of thromboembolic events and osteoporosis decreased (Table). Variations in incidence rates were noted depending on recording mechanism (e.g. registry, clinic visit, telephone, information from family).

 Unadjusted Incidence Rate/1000 pt-yrs (95% CI)Adverse EventDuring original studyDuring LTFUMyocardial Infarction1.7 (1.4-2.0)3.5 (2.7-4.5)Thromboembolic event6.0 (5.4-6.6)2.5 (1.8-3.3)Osteoporosis23.6 (22.5-24.9)18.2 (16.3-20.3)Bone fractures17.2 (16.2-18.3)15.0 (13.2-16.9)

Overall 1845 deaths were reported; the unadjusted incidence of death was lower in the original study compared with during LTFU (21.9 vs. 26.6/1000 pt-yrs); incidence remained relatively stable for pts assigned to tamoxifen (24.9 vs. 25.2/1000 pt-yrs), and increased for pts assigned to letrozole (22.0 vs. 27.1/1000 pt-yrs).

Conclusions

The BIG 1-98 LTFU study has been successfully conducted. The additional data from the BIG 1-98 LTFU study provides important long-term clinical information about OS, DFS and adverse events.

Citation Format: Thürlimann B, Giobbie-Hurder A, Colleoni M, Jensen M-B, Ejlertsen B, de Azambuja E, Neven P, Láng I, Gladieff L, Bonnefoi H, Harvey VJ, Spazzapan S, Tondini C, Price K, Piccart-Gebhart M, Regan MM, Gelber RD, Coates AS, Goldhirsch A. 12 years' median follow up (MFU) of BIG 1-98: Adjuvant letrozole, tamoxifen and their sequence for postmenopausal women with endocrine responsive early breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-09-05.