Prognostic value of EndoPredict test in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative primary breast cancer screened for the randomized, double-blind, phase III UNIRAD trial

BACKGROUND

The purpose of this study was to evaluate the prognostic value of the multigene EndoPredict test in prospectively collected data of patients screened for the randomized, double-blind, phase III UNIRAD trial, which evaluated the addition of everolimus to adjuvant endocrine therapy in high-risk, hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative early breast cancer.

PATIENTS AND METHODS

Patients were classified into low or high risk according to the EPclin score, consisting of a 12-gene molecular score combined with tumor size and nodal status. Association of the EPclin score with disease-free survival (DFS) and distant metastasis-free survival (DMFS) was evaluated using Kaplan-Meier estimates. The independent prognostic added value of EPclin score was tested in a multivariate Cox model after adjusting on tumor characteristics.

RESULTS

EndoPredict test results were available for 768 patients: 663 patients classified as EPclin high risk (EPCH) and 105 patients as EPclin low risk (EPCL). Median follow-up was 70 months (range 1-172 months). For the 429 EPCH randomized patients, there was no significant difference in DFS between treatment arms. The 60-month relapse rate for patients in the EPCL and EPCH groups was 0% and 7%, respectively. Hazard ratio (HR) supposing continuous EPclin score was 1.87 [95% confidence interval (CI) 1.4-2.5, P < 0.0001]. This prognostic effect remained significant when assessed in a Cox model adjusting on tumor size, number of positive nodes and tumor grade (HR 1.52, 95% CI 1.09-2.13, P = 0.0141). The 60-month DMFS for patients in the EPCL and EPCH groups was 100% and 94%, respectively (adjusted HR 8.10, 95% CI 1.1-59.1, P < 0.0001).

CONCLUSIONS

The results confirm the value of EPclin score as an independent prognostic parameter in node-positive, hormone receptor-positive, HER2-negative early breast cancer patients receiving standard adjuvant treatment. EPclin score can be used to identify patients at higher risk of recurrence who may warrant additional systemic treatments.

Overall survival in the OlympiA phase III trial of adjuvant olaparib in patients with germline pathogenic variants in BRCA1/2 and high risk, early breast cancer

BACKGROUND

The randomized, double-blind OlympiA trial compared 1 year of the oral poly(adenosine diphosphate-ribose) polymerase inhibitor, olaparib, to matching placebo as adjuvant therapy for patients with pathogenic or likely pathogenic variants in germline BRCA1 or BRCA2 (gBRCA1/2pv) and high-risk, human epidermal growth factor receptor 2-negative, early breast cancer (EBC). The first pre-specified interim analysis (IA) previously demonstrated statistically significant improvement in invasive disease-free survival (IDFS) and distant disease-free survival (DDFS). The olaparib group had fewer deaths than the placebo group, but the difference did not reach statistical significance for overall survival (OS). We now report the pre-specified second IA of OS with updates of IDFS, DDFS, and safety.

PATIENTS AND METHODS

One thousand eight hundred and thirty-six patients were randomly assigned to olaparib or placebo following (neo)adjuvant chemotherapy, surgery, and radiation therapy if indicated. Endocrine therapy was given concurrently with study medication for hormone receptor-positive cancers. Statistical significance for OS at this IA required P < 0.015.

RESULTS

With a median follow-up of 3.5 years, the second IA of OS demonstrated significant improvement in the olaparib group relative to the placebo group [hazard ratio 0.68; 98.5% confidence interval (CI) 0.47-0.97; P = 0.009]. Four-year OS was 89.8% in the olaparib group and 86.4% in the placebo group (Δ 3.4%, 95% CI -0.1% to 6.8%). Four-year IDFS for the olaparib group versus placebo group was 82.7% versus 75.4% (Δ 7.3%, 95% CI 3.0% to 11.5%) and 4-year DDFS was 86.5% versus 79.1% (Δ 7.4%, 95% CI 3.6% to 11.3%), respectively. Subset analyses for OS, IDFS, and DDFS demonstrated benefit across major subgroups. No new safety signals were identified including no new cases of acute myeloid leukemia or myelodysplastic syndrome.

CONCLUSION

With 3.5 years of median follow-up, OlympiA demonstrates statistically significant improvement in OS with adjuvant olaparib compared with placebo for gBRCA1/2pv-associated EBC and maintained improvements in the previously reported, statistically significant endpoints of IDFS and DDFS with no new safety signals.

Abstract P4-13-13: Meta-analyses of visceral versus non-visceral metastases treated by AI & SERD agents as 2nd line endocrine therapy (ET) for HR+ breast cancer (BC)

There is a prevailing belief that ET for HR+ advanced BC is not as effective in patients with visceral metastases (VM) compared to non-visceral metastases (nVM), particularly with later lines of ET. Recently fulvestrant 500mg (Ful 500), has been reported to have greater efficacy in nVM compared to i) VM treated by Ful 500 but also compared to ii) nVM treated by Ful 250 (2nd line) and iii) nVM treated by aromatase inhibitor (AI), anastrozole (1st Line) – implying both site and agent related efficacy. Absence of significant overall survival (OS) difference in PALOMA 3 (2nd line) has increased the debate regarding when to add CDK 4/6is to ET, especially given the OS advantage for Ful 500 monotherapy in the 1st & 2nd line settings.

Patients & Methods: Anonymised, individual patient level data was obtained from randomised controlled trials (RCTs) involving AI & SERD used as mono-theraphy in 2nd or 3rd Line setting in known HR+ BC. All the trials were Phase 3 double-blind, placebo RCTs. All were rigorously assessed for clinical benefit (CB), progression free survival (PFS), duration of CB (DoCB) and OS. Details of the studies, types of ET and patient numbers are shown in the Table.

Results: Outcome data is presented for each study and then summarised under AI, SERD (Ful 250 or 500) and 'all Ets combined'. Odds ratios (Ors) & hazard ratios (HRs) for VM versus nVM by endocrine agents are shown in the Table.

AgentStudyTotal Pats.HR+ Pats.CBRPFSOSDoCBAI(n)(n)OR (95%Cis)HR (95%Cis)HR (95%Cis)HR (95%Cis)Exe00202301831.181.441.271.50Exe00211931681.151.951.832.12AnaEFECT3403360.941.521.201.10AnaSOFEA2492491.291.181.051.41subtotal7636871.11 (0.84-1.48)1.47*** (1.22-1.79)1.21* (1.01-1.45)1.43** (1.10-1.86)SERDFul 25000202191601.791.701.401.23Ful 25000212041771.281.811.322.06Ful 250EFECT3513450.791.401.311.03Ful 250SOFEA2312310.701.171.242.22Ful 250CONFIRM1521521.131.071.510.84Subtotal9268341.05 (0.75-1.45)1.39*** (1.16-1.67)1.34*** (1.14-1.57)1.36 (0.93-1.98)SERDFul 500CONFIRM1441442.24 (1.12-4.48)1.30 (0.90-1.87)1.33 (1.14-1.57)0.97 (0.55-1.66)All ETsTotal183316651.13 (0.92-1.39)1.42*** (1.26-1.59)1.28*** (1.14-1.44)1.35** (1.09-1.66)

[Pats=Patients; (n)=number; CBR-Clinical Benefit Rate; p-values p&lt;0.05*, p&lt;0.01**, p&lt;0.001***]

Median PFS (months) for nVM for AI, SERD250, SERD500 & ‘all Ets combined’ were 5.4, 5.5, 11.0 & 5.5 respectively: for VM they were 2.9, 3.5, 5.5 & 3.2 respectively.

Median OS (months) for nVM for AI, SERD250, SERD500 & ‘all Ets combined’ was 24.2, 26.0, 35.4 & 25.4 respectively: for VM the figures were 22.8, 20.8, 26.4 & 22.0 respectively.Conclusions:1) In the 2nd line HR+ setting AI & Ful 250 both significantly increased PFS & OS in nVM versus VM. Longer PFS appears due to longer duration of control (DoCB) than increasing the number of patients responding (CBR).

2) Median OS for nVM ranged from 24 – 35 months versus 20.8-26.4 months for VM: for the majority of patients the 2nd line ET setting is not ‘immediately life threating’ and ET is therefore an option to consider.

3) These data on site of disease (nVM vs VM) contribute to the selection of which patients should receive endocrine mono- and which endocrine combination therapy (ie plus mTORi or CDK4/6i) in the second line setting.

Citation Format: Robertson JFR, Di Leo A, Johnston S, Chia S, Bliss J, Bradbury I, Campbell C. Meta-analyses of visceral versus non-visceral metastases treated by AI & SERD agents as 2nd line endocrine therapy (ET) for HR+ breast cancer (BC) [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 P4-13-13.

Abstract GS3-02: PALLET: A neoadjuvant study to compare the clinical and antiproliferative effects of letrozole with and without palbociclib

Background: CDK4/6 inhibitors, such as palbociclib, are used to treat ER+ metastatic breast cancer in combination with endocrine therapy with trials ongoing in patients with primary disease. No biomarkers exist to identify those who do/do not benefit from added CDK4/6 inhibition. PALLET is an investigator-initiated/led phase II randomized trial collaboration between UK and NSABP investigators evaluating the biological and clinical effects of palbociclib with letrozole combination as neoadjuvant therapy.

Methods: Postmenopausal women with ER+ primary breast cancer and tumors &gt;2.0cm (ultrasound) were randomized to one of 4 treatment groups (3:2:2:2 ratio): Group A: letrozole (2.5mg/d) for 14 weeks; Group B: letrozole for 2 weeks followed by letrozole + palbociclib to 14 weeks; Group C: palbociclib for 2 weeks followed by letrozole + palbociclib to 14 weeks; Group D: letrozole + palbociclib for 14 weeks. Palbociclib was given 125mg/d PO on a 21 days on, 7 days off schedule. Post-14 week treatment was at the discretion of the treating clinician including letrozole until surgery. Core-cut biopsies were taken at baseline, 2 weeks and 14 weeks. Co-primary endpoints for letrozole alone vs palbociclib groups (Group A vs Groups B+C+D) were: (i) change in Ki67 (IHC) between baseline and 14 weeks (log-fold change, Mann-Whitney test); (ii) clinical response (ultrasound) after 14 weeks (4 group, ordinal, Mann-Whitney test). Complete cell-cycle arrest (CCCA) (Ki67≤2.7%) was analyzed using a logistic regression model adjusting for recruitment region. Pre-specified exploratory biomarkers included c-PARP (apoptosis).

Results: 307 patients were recruited between 27 Feb 2015 and 08 Mar 2018; 103 were randomized to letrozole alone and 204 to letrozole + palbociclib. 279 (90.9%) patients were evaluable for 14 week clinical response. Clinical response was not significantly different between letrozole vs letrozole + palbociclib groups [(p=0.20; CR+PR 49.5% (46/93) vs 54.3% (101/186) and PD 5.4% (5/93) vs 3.2% (6/186)] nor was the small proportion of patients with pathological CR (1/87, 1.1% vs 6/180, 3.3%; p=0.43). 190 (61.9%) patients were evaluable for 14 week change in Ki67. The median log-fold change in Ki67 was greater with letrozole + palbociclib vs letrozole alone (-4.1 vs -2.2; p&lt;0.001) corresponding to a geometric mean change of -97.4% vs -88.5%. Similarly, a greater proportion of patients who received letrozole + palbociclib achieved CCCA (90% vs 59%, p&lt;0.001). 146 (47.6%) patients were evaluable for c-PARP and the log-fold change (suppression) was greater with letrozole + palbociclib vs letrozole alone (-0.80 vs -0.42; p=0.003) corresponding to a geometric mean change of -56.8% vs -31.4%. Other biomarkers of response / resistance are being evaluated. A higher proportion of patients had a grade ≥3 toxicity on letrozole + palbociclib than letrozole alone (49.8% vs 17.0%; p&lt;0.001) mainly due to asymptomatic neutropenia.

Conclusion: Adding palbociclib to letrozole markedly enhanced the suppression of malignant cell proliferation as assessed by Ki67 but did not substantially increase the clinical response of primary ER+ breast cancer over a 14-week period. Concurrent reductions in cell death may have reduced the speed of tumor shrinkage.

Citation Format: Dowsett M, Jacobs S, Johnston S, Bliss J, Wheatley D, Holcombe C, Stein R, McIntosh S, Barry P, Dolling D, Snowdon C, Perry S, Batten L, Dodson A, Martins V, Modi A, Cornman C, Puhalla S, Wolmark N, Julian T, Pogue-Geile K, Robidoux A, Provencher L, Boileau JF, Shalaby I, Thirlwell M, Fisher K, Huang Bartlett C, Koehler M, Osborne K, Rimawi M. PALLET: A neoadjuvant study to compare the clinical and antiproliferative effects of letrozole with and without palbociclib [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 GS3-02.

Abstract OT1-06-03: The plasmaMATCH trial: A multiple parallel cohort, open-label, multi-centre phase II clinical trial of ctDNA screening to direct targeted therapies in patients with advanced breast cancer (CRUK/15/010)

Introduction

Circulating tumour DNA (ctDNA) is found in the plasma of over 90% of patients with advanced breast cancer (BC). Screening for the presence of mutations in ctDNA provides a current assessment of the genetic profile of the patient's recurrent BC. The plasmaMATCH trial is designed to assess the potential of ctDNA screening to direct targeted therapies in patients with advanced breast cancer.

Methods

plasmaMATCH is a multi-centre phase IIa umbrella trial platform of ctDNA screening and a therapeutic trial. The study will screen 1000 women with advanced breast cancer, who have received prior systemic treatment in the advanced setting, with digital PCR ctDNA assays for hotspot mutations in ESR1, HER2, AKT1, and PIK3CA, with HER2 copy number assessment, in a central laboratory. The study will recruit from up to 50 sites in the UK. Patients with mutations identified will enter the matching treatment cohort, ESR1 – extended dose fulvestrant 500mg every two weeks, HER2 – neratinib +/- fulvestrant, AKT1 – AZD5363 +/- fulvestrant.

Mutation prevalence is presented with corresponding exact 95% confidence intervals (CIs) both overall and excluding 14 patients who were known to have mutations from a prior screening program. Patients with more than one mutation are included once in each relevant row.

Results

We report the results of prospective ctDNA mutation testing in the first 92 patients. plasmaMATCH opened to recruitment on 15/12/2016. As of 08/06/2017, 120 patients have been registered for ctDNA screening from 7 UK centres, of which 92 have ctDNA screening results available:

plasmaMATCH ctDNA screening resultsMutationPrevalence (95% CI)Prevalence excluding 14 patients with known mutations (95% CI)ESR134/92: 37% (27%-48%)26/78: 33% (23%-45%)HER25/90: 6% (2%-12%)2/76: 3% (0%-9%)AKT17/92: 8% (3%-15%)4/78: 5% (1%-13%)PIK3CA*22/92: 24% (16%-34%)21/78: 27% (18%-38%)*No corresponding plasmaMATCH treatment cohort

14 patients had more than one mutation detected (10 ESR1+PIK3CA, 3 ESR1+AKT1, 1 ESR1+ +HER2+AKT1). ctDNA results were reported in a median of 8 working days.

Of the 40 patients with one or more actionable mutation, 15 have entered a cohort, 16 are being screened for entry into a cohort, 5 are currently receiving further systemic treatment prior to cohort entry and 4 will not enter a cohort. One additional patient has entered a treatment cohort on the basis of a mutation detected in an alternative tumour sequencing initiative.

Conclusions

plasmaMATCH ctDNA demonstrates the feasibility and accuracy of ctDNA testing as a screening tool for patients with advanced BC, with a high rate of subsequent recruitment into matching therapeutic trials.

Citation Format: Turner N, Bye H, Kernaghan S, Proszek P, Fribbens C, Moretti L, Morden J, Snowdon C, Macpherson I, Wardley A, Roylance R, Baird R, Bliss J, Ring A. The plasmaMATCH trial: A multiple parallel cohort, open-label, multi-centre phase II clinical trial of ctDNA screening to direct targeted therapies in patients with advanced breast cancer (CRUK/15/010) [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 OT1-06-03.

Abstract GS3-03: A phase III multicentre double blind randomised trial of celecoxib versus placebo in primary breast cancer patients (REACT – Randomised EuropeAn celecoxib trial)

Background

Inhibition of COX-2 has been shown to attenuate the metastatic process in pre-clinical models of human breast cancer (BC). The primary aim of this study was to assess the effect of 2 years adjuvant therapy with the COX-2 inhibitor celecoxib compared with placebo in HER2-ve primary BC patients.

Patients & Methods

Patients were randomised in a 2:1 ratio to receive celecoxib 400mg once daily or placebo for 2 years. Patients had to have completely resected BC with prior local and systemic adjuvant treatment according to local practice. Concurrent radiotherapy was permitted and hormone receptor +ve patients received endocrine therapy according to local practice. Patients with HER2+ or node negative, T1 and grade 1 disease were excluded. Median age of patients was 55 years (IQR: 49-63). 50% of patients had tumours &gt;2cm; 42% were grade 3; 48% had node +ve disease. According to local assessment 73% were ER/PgR +ve. Primary endpoint was Disease Free Survival (DFS); defined as time from randomisation to date of first event, with events contributing to analysis defined as recurrence (distant/local), new primary BC (ipsilateral/contralateral) and death. Secondary endpoints included Overall Survival (OS), toxicity, cardiovascular mortality and incidence of second primaries. Subgroup analysis by hormone receptor status was pre-planned. Survival endpoints are analysed using Cox-proportional hazards and log-rank tests; restricted mean survival is used where proportional hazards do not hold.

Results

Between January 2007 and November 2012, 2639 patients were randomised (1763 celecoxib; 876 placebo) from 181 centres across the UK and Germany. At 13th April 2017, median follow up was 60 months (IQR: 48-72) with 428 DFS events reported. Unadjusted survival analysis results are presented below, with hazard ratio&lt;1 favouring celecoxib:

 5 year survival estimate (95% CI)Hazard ratio (95% CI)p-valueDFS (all patients)   Celecoxib83% (81, 85)1.02 (0.83 – 1.24)0.88Placebo83% (80, 86)1-    DFS within ER+   Celecoxib87% (85, 89)0.89 (0.69 – 1.16)0.40Placebo86% (83, 89)1-    DFS within ER-   Celecoxib72% (68, 76)1.17 (0.85 – 1.61)0.33Placebo75% (69, 80)1-    OS (all patients)   Celecoxib90% (88, 91)0.97 (0.75 – 1.25)0.81Placebo90% (88, 92)1-

The interaction between ER status and treatment was not significant; p=0.36.

In the celecoxib and placebo groups there were 17 and 8 deaths respectively in patients who had not relapsed. These were due to cardiac (n=3; 2) and other (n=14; 6) in the celecoxib and placebo groups respectively; none were GI related. In total 304 serious adverse events were observed in 265 patients (186/1763 celecoxib; 79/876 placebo). In the celecoxib and placebo groups respectively these were related to cardiac (n=12; 7), GI (n=9; 2) and other (n=193; 81). Work is ongoing to determine whether a subset of ER+ patients whose primary tumours show the characteristics of a COX-2 signature receive greater benefit from celecoxib.

Conclusions

There is no benefit of celecoxib in the ITT population. Further exploratory studies focussing on the ER+ subpopulation are ongoing. Celecoxib treatment is not associated with significant toxicity when compared to placebo in this population of BC patients.

Citation Format: Coombes RC, Tovey H, Kilburn L, Mansi J, Palmieri C, Bartlett J, Hicks J, Makris A, Evans A, Loibl S, Denkert C, Murray E, Grieve R, Coleman R, Schmidt M, Klare P, Rezai M, Rautenberg B, Klutinus N, Rhein U, Mousa K, Ricardo-Vitorino S, von Minckwitz G, Bliss J. A phase III multicentre double blind randomised trial of celecoxib versus placebo in primary breast cancer patients (REACT – Randomised EuropeAn celecoxib 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 GS3-03.

Abstract PD5-05: Genomic instability and poor antiproliferative response to aromatase inhibitor treatment: A POETIC study

Background:

More than 20% of early-stage patients with estrogen positive (ER+) disease relapse. Higher levels of the proliferation marker Ki67, and lack of reduction of Ki67 in response to AI indicate poorer prognosis. Somatic mutations have been the focus of research in treatment resistance. However, recurrent somatic copy number alterations (SCNAs) are more common and affect more genes in primary breast cancer (BC) than somatic mutations. Previous studies have suggested an increased risk of recurrence for patients with high genomic instability and for patients with loss of heterozygosity (LOH) at the TP53 locus, but it is unknown if these SCNA events impact response to AI treatment. In addition, LOH and mutations at the TP53 locus had a higher risk of recurrence than LOH or mutations at TP53 alone. We hypothesised that genomic instability and SCNAs at particular loci would be increased in early BC patients with high baseline Ki67, and particularly in patients with high Ki67 despite pre-operative AI therapy.

Methods:

In a substudy of POETIC (UK-wide, phase III, randomised trial with 4483 women testing perioperative AI in postmenopausal women with early BC), SNParray technology was used to determine SCNAs in baseline and surgical tumour core-cuts and blood from 76 patients (59 AI-treated, 17 controls). Proliferation rate was estimated as percentage (%) of cancer cells staining for Ki67 by IHC. Poor AI responders (PR, &lt;60% reduction in Ki67 between baseline and surgery, n=31) and good AI responders (GR, &gt; 75% reduction in Ki67, n=28) were selected from POETIC samples. Mutation data from exome sequencing was available for tumours from 75 of the patients.

Results:

The fraction of the genome with SCNAs correlated with Ki67 expression in both baseline and surgical samples (baseline Spearman rho=0.5, p &lt; 10-5; surgical Spearman rho=0.44, p &lt; 10-3). In paired baseline vs surgical samples, 24% of samples showed discordance in SCNAs that covered &gt; 10% of the genome. The samples showing the highest discordance were from PRs.

The fraction of the genome with LOH was greater in PR (median PR 20%, GR 10%, p = .065), and the best SCNA to predict the fraction of the genome altered in a sample were segments with LOH at Chr17p13.3 (adjusted p &lt; .001, logistic regression). There was a higher percentage of patients with LOH at Chr17p13.3 that contains the TP53 gene in the PR compared to GR group (PR 71%, GR 39%, p = .029), and integration of previously generated mutation data with SCNA showed that 9 out of 31 PRs have mutations and LOH at the TP53 locus compared to 3 out of 28 GRs (p = 0.16).

Conclusions:

There is discordance between the observed SCNAs in paired samples with high genomic instability and multiple biopsies may be needed to confidently assess all SCNAs. However, LOH at Chr17p13.3 is a biomarker for genomic instability and frequency of LOH is significantly greater in patients that show a poor response to AI treatment. Finally, high genomic instability is associated with high proliferation rates at baseline and surgery after 2 weeks of AI treatment suggesting de novo resistance in tumours with high instability that may lead to a higher rate of recurrence seen in these patients.

Citation Format: Schuster EF, Gellert P, Segal CV, López-Knowles E, Buus R, Morden J, Robertson J, Bliss J, Smith I, Dowsett M, POETIC Trial Management Group and Trialists P. Genomic instability and poor antiproliferative response to aromatase inhibitor treatment: A POETIC study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD5-05.

Abstract P2-02-01: Withdrawn

This abstract was withdrawn by the authors.

Abstract P2-10-02: The impact of intrinsic subtypes and molecular features on aromatase inhibitor induced reduction of proliferation marker of Ki67 in primary ER+ breast cancer: A POETIC study (CRUK/07/015)

Background

Neoadjuvant endocrine therapy (NAE) is often a good option for postmenopausal (PM) women with estrogen receptor positive (ER+) breast cancers(BC). Fall in Ki67 is widely accepted as valid for predicting favorable tumor response to NAE and improved outcome. We report our planned correlative study to investigate if intrinsic subtype impacts on Ki67 changes (ΔKi67) as measured by immunohistochemistry. We also explored the correlation of several ER+ BC relevant molecular features at baseline(B) with ΔKi67.

Patients and methods

POETIC is a phase III, randomized 2:1 study for 4486 PM patients with ER+ BC to determine whether peri-operative aromatase inhibitor (AI) followed by standard adjuvant therapy improves outcome compared with standard adjuvant therapy alone. The proliferation rate was estimated as percentage (%) of cancer cells staining for Ki67. Primary biological endpoint was defined as two-week (2wk) change in Ki67 (2wkΔKi67): ln[(2wk Ki67+0.1)/(B Ki67+0.1)]. Secondary endpoint: “responders”, was % change of Ki67 defined as (2wk Ki67 – B Ki67) *100/B Ki67. “Responder” was defined as follows: reduction &lt;50% as poor (PR), 50-75% moderate and &gt;75% as good responder (GR).

Human whole genome expression(GE) Illumina BeadChips were performed. Data was obtained from 137 paired samples from the treatment group(T) and 49 pairs from the control(C) group with GE data passing quality check and baseline Ki67≥5% to minimise the impact of extreme values based on proportional ΔKi67. Intrinsic subtype and risk of recurrence(ROR) groups were calculated using PAM50. GE scores from Oncotype Dx, MammaPrint, p53 mutation/wildtype(Troester 2006), ER+ early response (ERE)(Hatzis 2011), estrogen-regulated genes subtypes (Oh 2006) and markers for 23 different immune cell types(Bindea 2013) were calculated. Associations of GE scores to endpoints of response were determined by Spearman correlation and chi-square tests. Bonferroni correction was used to control error rate with p&lt;0.0005 deemed significant.

Results

At B of the 137 paired T, 64% were Luminal A (LumA), 22% Luminal B (LumB), 9% as HER-2 enriched (HER2-E), 2% as Basal-like (BLBC) and 3% as Normal-like. Subtypes at B were associated with response, with LumA showing the biggest reduction of Ki67 (p=0.0001) and GR. All GE, except ERE, correlated significantly with 2wkΔKi67 and response: higher risk groups associated with lowest reduction rate. None of immune cell types correlated with 2wkΔKi67, except that tumors enriched with T-helper 1 cell type were associated with PR (p &lt; 0.000001).

Comparing subtypes between time-points, 85% of LumB and 42% of HER2-E were assigned instead as LumA at 2wk regardless of response. Of the 15 ROR defined high-risk group, only 33% were assigned instead as low-risk at 2wk.

Conclusion

Both LumA and LumB are endocrine sensitive. A fall of Ki67 was observed in majority of cases. Most tumors estimated as high-risk by molecular profiling showed less response and most remained moderate or high risk of recurrence on endocrine therapy. Whether molecular profiling at 2wk after starting AI predicts for long-term outcome in PM women with ER+ better than at diagnosis will need to be determined.

Citation Format: Cheang MCU, Morden J, Gao Q, Parker J, López-Knowles E, Detre S, Hills M, Zabaglo L, Tomiczek M, Mallon E, Robertson J, Smith I, Bliss J, Dowsett M, On Behalf of the POETIC Trialists. The impact of intrinsic subtypes and molecular features on aromatase inhibitor induced reduction of proliferation marker of Ki67 in primary ER+ breast cancer: A POETIC study (CRUK/07/015) [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 P2-10-02.

Abstract P1-02-01: Circulating tumor DNA analysis to predict relapse and overall survival in early breast cancer – Longer follow-up of a proof-of-principle study

Background

In a previous proof-of-principle study we demonstrated that detection of circulating tumour DNA (ctDNA) in the adjuvant setting, after completion of surgery and chemotherapy for early stage breast cancer, was associated with a high risk of early relapse. Here we present longer follow-up of the same series, to define the predictive power of ctDNA analysis for disease free survival, and assess the potential to predict overall survival.

Methods

We recruited a cohort of 55 women presenting with early stage, primary breast cancer, who were all scheduled to receive neo-adjuvant chemotherapy. The primary tumour was sequenced to identify somatic mutations, identifying at least one mutation in 43 patients. Mutations were tracked with digital PCR to identify ctDNA, in plasma samples taken either at a single post-surgical time point (2-6 weeks post-surgery) or with serial plasma samples taken every 6 months in the adjuvant setting.

Results

At a median 31.7 months follow-up, 42% (18/43) patients had relapsed. Detection of ctDNA at the single post-surgical time point was associated with poor disease free survival, HR=13.6 95%CI (4.5, 41.2) p&lt;0.001, and overall survival HR=84.7 95%CI (9.8, 730.4) p&lt;0.001. All patients with ctDNA detected in a single post-surgical time point relapsed and died in the follow-up period (7/7, 100% specificity), although the single post-surgery time point had modest 39% (7/18) sensitivity for relapse. Detection of ctDNA at any point in serial sampling was associated with poor disease free survival HR=25.7 95%CI (8.3, 79.8) p&lt;0.001 and overall survival HR=47.1 95%CI (6.1, 366.1) p&lt;0.001. All patients with ctDNA detected in a serial mutation tracking relapsed in the follow-up period (14/14, 100% specificity), with 78% (14/18) sensitivity for relapse. Sensitivity was limited by 3 cases of brain only relapse and one case of solitary ovarian relapse. Detection of ctDNA in serial sampling had a median lead-time of 8.1 months over clinical relapse.

Conclusion

Detection of ctDNA in the adjuvant setting has a high predictive power for future relapse and death from breast cancer. Therapeutic trials are required to determine whether mutation tracking identifies relapse sufficiently early to allow for further adjuvant therapy.

Citation Format: Turner NC, Garcia-Murillas I, Chopra N, Beaney M, Kilburn L, Cutts R, Osin P, Nerurkar A, Schiavon G, Hrebien S, Bliss J, Dowsett M, Smith I. Circulating tumor DNA analysis to predict relapse and overall survival in early breast cancer – Longer follow-up of a proof-of-principle study [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 P1-02-01.

Abstract P2-09-02: True effect of aromatase inhibitor (AI) treatment on global gene expression (expr) changes in postmenopausal ER+ breast cancer (BC) patients: A POETIC study (CRUK/07/015)

BACKGROUND Gene expression (expr) analyses are increasingly used for characterising the pharmacodynamic response of primary BC. This includes assessing ER+ BC's dependence on estrogen (E) by measuring gene expr changes after AI-treatment. However, differences in tissue sampling and other preanalytic procedures between samples taken at diagnosis (D) and surgery (S), may lead to systematic artifactual changes that are falsely ascribed to the intervention. To identify genes whose expr is truly affected by AI, we measured global gene expr changes from paired core-cut biopsies at D and S from patients in the POETIC presurgical window trial.

METHODS In POETIC, 4486 postmenopausal women with primary ER+ BC were randomised 2:1 to receive perioperative AI (2 weeks pre + 2 weeks post surgery, termed Tr) or no perioperative treatment (termed Con), allowing gene expr changes to be compared between Tr and Con. RNA was extracted from paired RNA-later stored core-cuts of 56 Con and 157 Tr patients and arrayed on Illumina whole genome expr BeadChips. Raw data was extracted, transformed, normalised and batch-corrected. Probes not detected (p&gt;0.01) in &gt;=25% of samples were discarded. Impact of AI on genes was evaluated based on difference of the expr mean changes (log2(S/D)) of the Tr and Con samples.

RESULTS In the Con group, expr of 73 genes significantly changed (FDR&lt;5%); 70 of these changed by a similar magnitude in the Tr group, indicating their change was independent of AI therapy but would have been artifactually discovered as changed by AI in the absence on Con. The 8 genes most up-regulated in Tr were all among the 20 genes most up-regulated in Con: many were early-response or stress-associated genes. Three of the 8 most down-regulated in AI were the most down-regulated in Con: all were haemoglobin-related. Expr of some genes was changed in Con (eg MYC increase) but was unaffected in Tr. Such artifactual gene changes in Con tumors conceal true AI-induced changes that would not be detected in the absence of comparison with Con.

615 genes were down-regulated and 472 up-regulated in Tr but not Con. The majority of down-regulated genes were cell cycle or proliferation-associated or E-regulated, including ESR1, PDZK1, GREB1, HSPB1. Functional mapping showed changes in the regulation of cyclins and cyclin dependent kinases impacting on G1/S and G2/M. Of note, up-regulated genes included CDK6 (target for CDK4/6 inhibitors) and CCND2, involved in G1/S checkpoint regulation; SNAI2, TGFB3, TGFBR2, associated with tumour invasion and metastasis; and other genes involved in aryl hydrocarbon receptor, Glioblastoma Multiforme, HIPPO and p53 signalling.

CONCLUSION Expr of certain genes is altered by processes involved in presurgical window studies. In the absence of a Con group, these may be wrongly ascribed to an experimental intervention or wrongly considered as unaffected by the intervention (eg MYC in this study).

Down-regulation of E-responsive and proliferation genes was an expected response to AI but increased expr of genes such as SNAI2, CCND2 and CDK6 indicates immediate tumour re-wiring and provides mechanistic support for benefit from combination therapy with a CDK4/6 inhibitor.

Citation Format: Gao Q, López-Knowles E, Cheang MCU, Morden J, Martin L-A, Sidhu K, Evans D, Martins V, Dodson A, Skene A, Holcombe C, Mallon E, Abigail E, Bliss J, Robertson J, Smith I, Dowsett M. True effect of aromatase inhibitor (AI) treatment on global gene expression (expr) changes in postmenopausal ER+ breast cancer (BC) patients: A POETIC study (CRUK/07/015) [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 P2-09-02.

Reversal of the Cry-Wolf Effect: An Investigation of Two Methods to Increase Alarm Response Rates

In complex task environments, false alarms have been associated with less frequent and slower alarm responses. This research attempted to improve alarm responses using a hearsay method, in which participants were told that false alarms would be less frequent than they actually were, and an urgency method, in which the urgency of alarms was increased. Response frequency, speed, and accuracy of three groups of 20 students (Urgency, Hearsay, and Control) were compared across groups and sessions using analyses of variance and t tests. Both methods were successful; hearsay participants increased their response rates across sessions, and urgency participants decreased their response times. The results are discussed with regard to design of alarm systems and theory of human performance.

Extreme chromosomal instability forecasts improved outcome in ER-negative breast cancer: a prospective validation cohort study from the TACT trial

BACKGROUND

Chromosomal instability (CIN) has been shown to be associated with drug resistance and poor clinical outcome in several cancer types. However, in oestrogen receptor (ER)-negative breast cancer we have previously demonstrated that extreme CIN is associated with improved clinical outcome, consistent with a negative impact of CIN on tumour fitness and growth. The aim of this current study was to validate this finding using previously defined CIN thresholds in a much larger prospective cohort from a randomised, controlled, clinical trial.

PATIENTS AND METHODS

As a surrogate measurement of CIN, dual centromeric fluorescence in situ hybridisation was performed for both chromosomes 2 and 15 on 1173 tumours from the breast cancer TACT trial (CRUK01/001). Each tumour was scored manually and the mean percentage of cells deviating from the modal centromere number was used to define four CIN groups (MCD1-4), where tumours in the MCD4 group were defined as having extreme CIN.

RESULTS

In a multivariate analysis of disease-free survival, with a median follow-up of 91 months, increasing CIN was associated with improved outcome in patients with ER-negative cancer (P trend = 0.03). A similar pattern was seen in ER-negative/HER2-negative cancers (Ptrend = 0.007).

CONCLUSIONS

This prospective validation cohort study further substantiated the association between extreme CIN and improved outcome in ER-negative breast cancers. Identifying such patients with extreme CIN may help distinguish good from poor prognostic groups, and therefore support treatment and risk stratification in this aggressive breast cancer subtype.

Guidelines for time-to-event end point definitions in breast cancer trials: results of the DATECAN initiative (Definition for the Assessment of Time-to-event Endpoints in CANcer trials)†

BACKGROUND

Using surrogate end points for overall survival, such as disease-free survival, is increasingly common in randomized controlled trials. However, the definitions of several of these time-to-event (TTE) end points are imprecisely which limits interpretation and cross-trial comparisons. The estimation of treatment effects may be directly affected by the definitions of end points. The DATECAN initiative (Definition for the Assessment of Time-to-event Endpoints in CANcer trials) aims to provide recommendations for definitions of TTE end points. We report guidelines for randomized cancer clinical trials (RCTs) in breast cancer.

PATIENTS AND METHODS

A literature review was carried out to identify TTE end points (primary or secondary) reported in publications of randomized trials or guidelines. An international multidisciplinary panel of experts proposed recommendations for the definitions of these end points based on a validated consensus method that formalize the degree of agreement among experts.

RESULTS

Recommended guidelines for the definitions of TTE end points commonly used in RCTs for breast cancer are provided for non-metastatic and metastatic settings.

CONCLUSION

The use of standardized definitions should facilitate comparisons of trial results and improve the quality of trial design and reporting. These guidelines could be of particular interest to those involved in the design, conducting, reporting, or assessment of RCT.

Abstract S4-07: Effects of bisphosphonate treatment on recurrence and cause-specific mortality in women with early breast cancer: A meta-analysis of individual patient data from randomised trials

Background: Disseminated tumour cells can remain dormant in the bone marrow for years prior to subsequent activation and the development of overt metastases. Bisphosphonates (BP) have profound effects on bone physiology and could potentially modify the metastatic disease process. Variable outcomes in terms of disease recurrence have been reported, with efficacy apparently influenced by menopausal status.

Methods: We sought individual patient data for meta-analysis from 41 randomised trials that compared BP to no BP (placebo or open control). Primary outcomes were time to recurrence, time to first distant recurrence and breast cancer mortality. Predefined subgroup comparisons were of type of BP (amino-/non-amino), duration and schedule of BP treatment, menopausal status, age, ER status, concomitant chemotherapy and site of distant recurrence (bone/other).

Results: Data on 17,751 women (75% of 23,573 randomised in relevant trials) have so far been received, with around 3,300 breast cancer recurrences and 2,500 deaths. Effects on breast cancer mortality, recurrence and bone metastases for 17,016 women in the locked database and for 10,540 who were postmenopausal are shown below.

No. eventsRate Ratio (SE)10 year gain2p valueAll women (n = 17,016)Breast cancer mortality2,0490.91 (0.04)1.7%0.04Breast cancer recurrence3,2840.94 (0.04)1.0%0.13Distant recurrence2,7510.92 (0.04)1.3%0.05Bone recurrence8250.79 (0.07)1.4%0.002Other distant recurrence1,9260.99 (0.05)0.1%0.8Postmenopausal women (n = 10,540)Breast cancer mortality1,1070.83 (0.06)3.1%0.004Breast cancer recurrence1,8090.86 (0.05)3.0%0.002Distant recurrence1,5030.83 (0.05)3.3%0.0007Bone recurrence4450.65 (0.08)2.9%0.00001Other distant recurrence1,0580.93 (0.06)0.7%0.26

Reductions in bone recurrence for postmenopausal women were similar irrespective of bisphosphonate type, treatment schedule, ER status, nodal involvement or use of concomitant chemotherapy. There were no improvements in bone (RR = 1.00, 2p = 0.97) or other recurrence for premenopausal women. Adjuvant bisphosphonates also reduced bone fractures (RR = 0.83, 2p = 0.009).

Conclusion: Adjuvant bisphosphonates reduce bone recurrences and improve breast cancer survival in postmenopausal but not premenopausal women.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr S4-07.

Abstract P2-19-10: Quality of life following mastectomy and breast reconstruction (QUEST): Learning from two feasibility randomized controlled clinical trials

Background: Breast reconstruction (BRR) aims to improve health related quality of life (HRQL) after mastectomy, but with poor evidence to date informing the optimal type or timing of surgery to guide shared-decision making. Systematic reviews show the paucity of randomised trials (RCT) with only two-singe centre RCTs. Although, an RCT has theoretical advantages, there have been concerns that clinicians may not share clinical equipoise regarding recommending types of BRR surgery that is sensitive to patient preferences. The aim of the QUEST trials (CRUK/08/027) was to determine the optimal types of latissimus dorsi (LD) BRR (Trial A) when there is no expectation for post-mastectomy radiotherapy (PMRT), and timings of LDBRR when PMRT is recommended (Trial B), that would benefit HRQL during five years post-operatively. As this was the first attempt at a multi-centre RCT, the main trial was preceded by a feasibility phase to demonstrate that recruitment was achievable and that randomization was acceptable to patients. An embedded qualitative study, the QUEST Perspective Study (QPS) assessed the perceptions of equipoise of patients and health care professionals (HCPs) for the types of surgery.

Methods: QUEST comprised two parallel phase III multicentre feasibility RCTs to assess HRQL impact of the type of LDBRR when PMRT is unlikely (Trial A, LD - implant assisted (LDI) versus extended autologous LD (ALD)). Trial B evaluated optimal timings of LDBRR comparing staged - delayed ALD (skin-preserving sub-pectoral expander implant then ALD) to immediate ALD when PMRT was likely.

Eligible patients comprised mastectomy recommended for invasive breast cancer or DCIS in the context of technical feasibility for ALD and preferred synchronous breast reduction. The primary endpoint was the proportion of eligible women approached who accepted randomisation. QPS explored patients and HCPs’ acceptability of the trial and randomisation using semi-structured telephone interviews and questionnaires.

Results: The QUEST trials opened in May 2011 with 15 UK centres participating. After 18 months of recruitment, 17 patients had been entered in Trial A and 8 in trial B with acceptance rates of 19% (17/88) and 22% (8/36) for trial A and B respectively. Patient preference was the predominant reason for eligible patients approached about the trial not being randomised with 47 of the 88 (53%) for Trial A and 22 of 36 (61%) eligible for Trial B, declining for that reason. Patient acceptance rates for randomisation increased from 19% during the first 6 months to 29% from 7-12 months for Trial A; corresponding figures for Trial B were 11% and 27%. The recruitment challenges and funding cessation caused the Trial Steering Committee to recommend trial closure in December 2012.

Conclusion: Despite the need for clinical evidence, patients retained strong preferences for breast reconstruction type and timing, amidst ‘standardised’ trial processes. Patient acceptance rates did improve during the trial, but it was not possible to meet target recruitment within the constraints of a feasibility trial.

Funding for this NCRN portfolio trial (92581226) was from Cancer Research UK (CRUK) and BUPA Foundation funding for QPS.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-19-10.

Abstract P2-14-01: Fulvestrant vs exemestane for treatment of metastatic breast cancer in patients with acquired resistance to non-steroidal aromatase inhibitors – a meta-analysis of EFECT and SoFEA (CRUKE/03/021 & CRUK/09/007)

Background: Optimal endocrine treatment (trt) for post-menopausal women with ER+ advanced breast cancer (ABC) progressing on or following a non-steroidal (NS) aromatase inhibitor (AI) is unclear. The EFECT study showed no difference in efficacy between the steroidal antiestrogen fulvestrant (F) & steroidal AI exemestane (E) in this setting (HR = 0.96, 95%CI: 0.82, 1.13; p = 0.65). Pre-clinical data suggest F may be more effective in a low estrogen environment. SoFEA investigated F combined with anastrozole (F+A) in patients (pts) with acquired resistance to previous AI compared with F alone & F alone vs. E. The combination of F+A was no better than F (HR = 1.00, 95%CI: 0.83, 1.21; p = 0.98) nor F alone better than E (HR = 0.95, 95%CI: 0.79, 1.14; p = 0.56); the lack of added benefit for F+A is consistent with previous 1st-line studies that have assessed this combination versus A alone (FACT & SWOG-S0226).

Methods: SoFEA is a multi-center partially blinded randomized phase III study postmenopausal women were allocated to F plus A (F+A n=243), F plus placebo (n = 231) or E (n = 249). Similarly, EFECT is a randomized, double-blind, placebo controlled, multi-center phase III trial of F (n = 351) versus E (n = 342) in postmenopausal women (see table). However, given the differences in prior endocrine therapy/responsiveness within SoFEA & EFECT populations, an individual pt meta-analysis combining data from SoFEA & EFECT will be conducted enabling exploration of putative effects within specific pt subgroups to establish evidence in support, or not, of a pt subgroup sensitive to F at the dose used in these trials. Subgroups to be analysed include receptor status, visceral involvement, AI sensitivity, age, NSAI setting & time on NSAI.

Results: 723 pts (480 in F & E) were enrolled from 82 UK & 4 South Korean centers (03/2004-04/2010) in SoFEA. 693 pts were enrolled from 138 centers worldwide (08/2003-11/2005) in EFECT. Trt was well tolerated in both trials; serious adverse events were rare. The meta-analysis will be conducted in July 2012 & results presented.

Conclusion: Combining individual pt data from SoFEA & EFECT via meta-analysis will provide definitive clinical information on pt's response to F at the dose used in these studies, in particular whether certain pts with acquired resistance to NSAI do experience benefit of use of this antiestrogen as opposed to E.

Abstract PD07-07: Prediction of antiproliferative response to lapatinib by HER3 in an exploratory analysis of HER2-non-amplified (HER2−) breast cancer in the MAPLE presurgical study (CRUK E/06/039)

Aim: To identify pretreatment biomarker predictors of Ki67 response to lapatinib in women with HER2− primary breast cancer.

Background: Lapatinib is an EGFR/HER2 inhibitor. Its clinical use is restricted to HER2 overexpressing disease. The MAPLE (Molecular Antiproliferative Predictors of Lapatinib's Effects) presurgical window of opportunity study of lapatinib vs placebo was conducted in women with HER2-amplified (HER2+) or HER2− primary disease. Ki67 (primary end-point) was reduced by a geomean 46% (95%CI 23–63%, p = 0.002) and 27% (95%CI 8–42%, p = 0.008) in HER2+ and HER2− disease, respectively (Leary et al, AACR 2012). We have now assessed whether predictive biomarkers of the antiproliferative response in HER2− disease could be identified.

Methods: 121 primary breast cancer patients were randomized (3:1) to 14 days of 1500mg/d lapatinib or placebo before surgery. Biopsies were taken before treatment and at surgery. Ki67 responders were defined as having a &gt;/=50% reduction in Ki67 compared to baseline (Ellis, P et al, Breast Cancer Res Treat 1998, 48, 107). ER, PgR, HER2, EGFR, pAKT, pERK1/2 (nuclear and cytoplasmic), stathmin and apoptosis (TUNEL) were assessed by IHC (+FISH for HER2[all cases]) and scored visually by continuous methods. HER2, HER3, epiregulin (epir), amphiregulin (amphir) and neuregulin (neur) were assessed by qrtPCR.

Results: Three of the 121 patients were excluded because of inadequate biopsy material. Ninety-one of the remaining 118 patients received lapatinib: 7/19 (37%) HER2+ cases and 10/72 (14%) HER2− cases were Ki67 responders. Thus while the proportion of Ki67 responders was higher for HER2+ disease there was a similar or higher absolute number of responders with HER2− disease. All of the following relates to patients with HER2− disease. None of the pretreatment levels of ER, PgR, pAKT, pERK1/2, EGFR, epir, amphir or neur were associated with Ki67 response (p &gt; 0.20). However, HER3 (p = 0.01) and HER2 (p = 0.06) mRNA levels were associated with greater Ki67 response. There was a tendency for Ki67 response to be greater with lower baseline Ki67 (p = 0.07). Multivariate analysis showed only HER3 mRNA levels to be independently significant. HER2 and HER3 mRNA levels were highly correlated (rho = 0.67, p &lt; 0.001), a relationship confirmed in 2 other datasets (Wang et al, Breast Cancer Res, 2011, 13, R92; Dunbier et al, submitted). All Ki67 responders were above the median for both HER3 and HER2 expression.

Conclusions: Lapatinib is antiproliferative in a subgroup of HER2− tumours. This exploratory analysis indicates that they are characterized by high HER3 expression. The possible importance of high HER2:HER3 heterodimers in predicting this response is supported by the relationship between HER2 and HER3 expression. Further exploration of lapatinib is merited in HER2− cases with high HER3 expression.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD07-07.

The cost-effectiveness of adjuvant chemotherapy for early breast cancer: A comparison of no chemotherapy and first, second, and third generation regimens for patients with differing prognoses

BACKGROUND

The risk of recurrence following surgery in women with early breast cancer varies, depending upon prognostic factors. Adjuvant chemotherapy reduces this risk; however, increasingly effective regimens are associated with higher costs and toxicity profiles, making it likely that different regimens may be cost-effective for women with differing prognoses. To investigate this we performed a cost-effectiveness analysis of four treatment strategies: (1) no chemotherapy, (2) chemotherapy using cyclophosphamide, methotrexate, and fluorouracil (CMF) (a first generation regimen), (3) chemotherapy using Epirubicin-CMF (E-CMF) or fluorouracil, epirubicin, and cyclophosphamide (FEC60) (a second generation regimens), and (4) chemotherapy with FEC60 followed by docetaxel (FEC-D) (a third generation regimen). These adjuvant chemotherapy regimens were used in three large UK-led randomised controlled trials (RCTs).

METHODS

A Markov model was used to simulate the natural progression of early breast cancer and the impact of chemotherapy on modifying this process. The probability of a first recurrent event within the model was estimated for women with different prognostic risk profiles using a parametric regression-based survival model incorporating established prognostic factors. Other probabilities, treatment effects, costs and quality of life weights were estimated primarily using data from the three UK-led RCTs, a meta-analysis of all relevant RCTs, and other published literature. The model predicted the lifetime costs, quality adjusted life years (QALYs) and cost-effectiveness of the four strategies for women with differing prognoses. Sensitivity analyses investigated the impact of uncertain parameters and model assumptions.

FINDINGS

For women with an average to high risk of recurrence (based upon prognostic factors and any other adjuvant therapies received), FEC-D appeared most cost-effective assuming a threshold of £20,000 per QALY for the National Health Service (NHS). For younger low risk women, E-CMF/FEC60 tended to be the optimal strategy and, for some older low risk women, the model suggested a policy of no chemotherapy was cost-effective. For no patient group was CMF chemotherapy the preferred option. Sensitivity analyses demonstrated cost-effectiveness results to be particularly sensitive to the treatment effect estimate for FEC-D and the future price of docetaxel.

INTERPRETATION

To our knowledge, this analysis is the first cost-effectiveness comparison of no chemotherapy, and first, second, and third generation adjuvant chemotherapy regimens for early breast cancer patients with differing prognoses. The results demonstrate the potential for different treatment strategies to be cost-effective for different types of patients. These findings may prove useful for policy makers attempting to formulate cost-effective treatment guidelines in the field of early breast cancer.