Nab-paclitaxel weekly versus dose-dense solvent-based paclitaxel followed by dose-dense epirubicin plus cyclophosphamide in high-risk HR+/HER2- early breast cancer: results from the neoadjuvant part of the WSG-ADAPT-HR+/HER2- trial

BACKGROUND

In high-risk hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) early breast cancer (EBC), nanoparticle albumin-bound (nab)-paclitaxel showed promising efficacy versus solvent-based (sb)-paclitaxel in neoadjuvant trials; however, optimal patient and therapy selection remains a topic of ongoing research. Here, we investigate the potential of Oncotype DX® recurrence score (RS) and endocrine therapy (ET) response (low post-endocrine Ki67) for therapy selection.

PATIENTS AND METHODS

Within the WSG-ADAPT trial (NCT01779206), high-risk HR+/HER2- EBC patients were randomized to (neo)adjuvant 4× sb-paclitaxel 175 mg/m2 q2w or 8× nab-paclitaxel 125 mg/m2 q1w, followed by 4× epirubicin + cyclophosphamide (90 mg + 600 mg) q2w; inclusion criteria: (i) cN0-1, RS 12-25, and post-ET Ki67 >10%; (ii) cN0-1 with RS >25. Patients with cN2-3 or (G3, baseline Ki67 ≥40%, and tumor size >1 cm) were allowed to be included without RS and/or ET response testing. Associations of key factors with pathological complete response (pCR) (primary) and survival (secondary) endpoints were analyzed using statistical mediation and moderation models.

RESULTS

Eight hundred and sixty-four patients received neoadjuvant nab-paclitaxel (n= 437) or sb-paclitaxel (n = 427); nab-paclitaxel was superior for pCR (20.8% versus 12.9%, P = 0.002). pCR was higher for RS >25 versus RS ≤25 (16.0% versus 8.4%, P = 0.021) and for ET non-response versus ET response (15.1% versus 6.0%, P = 0.027); no factors were predictive for the relative efficacy of nab-paclitaxel versus sb-paclitaxel. Patients with pCR had longer distant disease-free survival [dDFS; hazard ratio 0.42, 95% confidence interval (CI) 0.20-0.91, P = 0.024]. Despite favorable prognostic association of RS >25 versus RS ≤25 with pCR (odds ratio 3.11, 95% CI 1.71-5.63, P ≤ 0.001), higher RS was unfavorably associated with dDFS (hazard ratio 1.03, 95% CI 1.01-1.05, P = 0.010).

CONCLUSIONS

In high-risk HR+/HER2- EBC, neoadjuvant nab-paclitaxel q1w appears superior to sb-paclitaxel q2w regarding pCR. Combining RS and ET response assessment appears to select patients with highest pCR rates. The disadvantage of higher RS for dDFS is reduced in patients with pCR. These are the first results from a large neoadjuvant randomized trial supporting the use of RS to help select patients for neoadjuvant chemotherapy in high-risk HR+/HER2- EBC.

Ten-year results of intense dose-dense chemotherapy show superior survival compared with a conventional schedule in high-risk primary breast cancer: final results of AGO phase III iddEPC trial

Background

Primary breast cancer (BC) patients with extensive axillary lymph-node involvement have a limited prognosis. The Arbeitsgemeinschaft fuer Gynaekologische Onkologie (AGO) trial compared intense dose-dense (idd) adjuvant chemotherapy with conventionally scheduled chemotherapy in high-risk BC patients. Here we report the final, 10-year follow-up analysis.

Patients and methods

Enrolment took place between December 1998 and April 2003. A total of 1284 patients with 4 or more involved axillary lymph nodes were randomly assigned to receive 3 courses each of idd sequential epirubicin, paclitaxel and cyclophosphamide (iddEPC) q2w or standard epirubicin/cyclophosphamide followed by paclitaxel (EC → P) q3w. Event-free survival (EFS) was the primary end point.

Results

A total of 658 patients were assigned to receive iddEPC and 626 patients were assigned to receive EC → P. The median duration of follow-up was 122 months. EFS was 47% (95% CI 43% to 52%) in the standard group and 56% (95% CI 52% to 60%) in the iddEPC group [hazard ratio (HR) 0.74, 95% CI 0.63-0.87; log-rank P = 0.00014, one-sided]. This benefit was independent of menopausal, hormone receptor or HER2 status. Ten-year overall survival (OS) was 59% (95% CI 55% to 63%) for patients in the standard group and 69% (95% CI 65% to 73%) for patients in the iddEPC group (HR = 0.72, 95% CI 0.60-0.87; log-rank P = 0.0007, two-sided). Nine versus two cases of secondary myeloid leukemia/myelodysplastic syndrome were observed in the iddEPC and the EC → P arm, respectively.

Conclusion

The previously reported OS benefit of iddEPC in comparison to conventionally dosed EC → P has been further increased and achieved an absolute difference of 10% after 10 years of follow-up.

Abstract GS5-06: No survival benefit of chemotherapy escalation in patients with pCR and “high-immune” triple-negative early breast cancer in the neoadjuvant WSG-ADAPT-TN trial

Background:Immune markers such as tumor infiltrating lymphocytes (TILs), CD8, PDL1, PD1 and other protein or mRNA-based genomic markers have been identified as prognostic / predictive in TNBC regarding survival / chemotherapy (CTx) efficacy.

In the adjuvant WSG-PlanB trial, patients with high TILs and/or CD8 by mRNA had excellent outcome, irrespective of anthracycline use; in the neoadjuvant ADAPT-TN trial, high PDL1, PD1 and CD8 and/or TILs were predictive for pCR. Still, optimal markers for potential treatment de-escalation have yet to be determined. Here, we analyse for the first time impact of immune mRNA-based markers and TIL's as prognostic and predictive survival markers.

Methods: TNBC patients (ER/PR<1%, HER2-,) were randomized to neoadjuvant 4x nab-paclitaxel 125 mg/m2/gemcitabine 1000 mg/m2 d1/8 q3w (gem arm) or 4x nab-paclitaxel 125 mg/m2/carboplatin AUC2 day 1/8 3-weekly (q3w) (carbo arm). Primary endpoint of WSG-ADAPT-TN was pCR (ypT0/is/ypN0); secondary endpoints included translational analyses, e.g., TILs or expression of 119 genes by nCounter platform. Standard adjuvant chemotherapy (4xEC) was optional (not randomized) in patients achieving pCR after 12 weeks. According to protocol, 1st safety survival analysis was performed after 3y median follow-up.

Results: Present translational analysis included 306 of 336 TNBC patients (36 months median FU). pCR was associated with significantly better survival (3y EFS: 92% vs. 71%, p<.001), but despite substantially higher pCR in the carbo arm (46% vs. 29%), no significant EFS advantage was seen (p=.6) (gem: 78%; carbo: 80%; 3y-EFS).

Bivariate Spearman correlations among CD8, PD1, and PDL1 were strongly positive; their correlations with TILs were moderately positive.

Preliminary Cox analysis of EFS was performed with clinical variables (cN, cT, menopausal status); neoadjuvant study arm; pCR; TILs; proliferation markers (baseline Ki67 by IHC, scores derived from PAM50); baseline immune markers; risk scores; and individual gene expression scores previously identified as prognostic for pCR in one or both neoadjuvant arms. Independent prognostic factors included pCR, cN, Ki67, PD1, and CD8; these were entered into (prognostic) interaction analysis. The resulting model contained cN, high Ki67 and low TILs as (unfavorable) main effects and the interaction of (higher) PD1*pCR (favorable).

Among pCR patients, the groups with/without additional adjuvant CTX were similar with respect to explanatory factors. Baseline TILs, Ki67, cN, and PD1 were entered into exploratory predictive analysis; the model retained only the interaction [adjuvant CTx * (fractionally ranked) PD1]. In patients with pCR, those with low PD1 benefited from standard anthracycline-containing adjuvant CTx, whereas patients high PD1 did not with an 98% 3y-EFS.

Conclusions: Our exploratory results suggest independent prognostic impact of mRNA markers and TIL's in early TNBC. Patients with both pCR (after 12 weeks) and “high-immune” signature (defined here by PD1) had excellent 3y-EFS and may be candidates for treatment de-escalation (e.g. omission of anthracyclines), whereas “low-immune” pCR patients may benefit from standard adjuvant poly-chemotherapy.

Citation Format: Gluz O, Nitz U, Liedtke C, Prat A, Christgen M, Feuerhake F, Garke M, Grischke E-M, Forstbauer H, Braun M, Warm M, Hackmann J, Uleer C, Aktas B, Schumacher C, Kuemmel S, Pelz E, Gebauer D, Paré L, Kates R, Wuerstlein R, Kreipe HH, Harbeck N. No survival benefit of chemotherapy escalation in patients with pCR and “high-immune” triple-negative early breast cancer in the neoadjuvant WSG-ADAPT-TN trial [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr GS5-06.

Abstract P6-13-01: Withdrawn

This abstract was withdrawn by the authors.

Abstract P2-10-03: Genomic markers but not molecular subtypes provide prognostic impact and predict anthracycline efficacy in early triple-negative breast cancer: Results from the prospective WSG PlanB trial

Background: Optimal treatment, particularly use of anthracyclines in aggressive triple-negative breast cancer (TNBC), is still a controversial issue in early BC management. However, TNBC exhibits substantial molecular heterogeneity: for example, the immune phenotype seems to be associated with better outcome. An important clinical issue in early TNBC is to quantify the impact of subtypes as well as individual genes on survival and especially on anthracycline benefit.

Methods: In PlanB, patients with ER and PR<1% (local or central lab), HER2- EBC were treated by TC (6 cycles Docetaxel/Cyclophosphamide) or EC-Doc (4xEpirubicin/Cyclophosphamideà4xDocetaxel) (overall n=2449, HER2-). RNA isolation was successfully performed in n=402/449 patients with available follow-up. Gene (n=119) expression data by Nanostring® platform were entered into univariate and multivariate Cox models for disease-free survival (DFS) to identify genes (and combinations) with potential prognostic and/or predictive impact. Median follow-up was 60 months.

Results: RNA expression results were available in n=394 (203 TC vs. 191 EC-Doc): PAM-50 subtype: basal-like 82%; HER2-enriched 7%; luminal (A or B) 3.5%; normal-like 7.4%. Median age was 54; 78% were node-negative. In patients with “discordant” tumors (HR positive by local or central assessment), 76% were still basal-like, compared to 86% in “concordant” TNBC. Of 27 patients with HER2-enriched subtype, HER2 status was positive by central assessment in only five cases (18%).

Within this TN cohort, 5y DFS was similar in TC (83%) and EC-Doc (79%) arms; positive nodal status and tumor size >2 cm were (unfavorable) clinical-pathological prognostic markers. Prognostic or predictive impacts of molecular subtype, risk of recurrence subgroups, or proliferation indices were not seen.

Twelve genes (incl. CD8, EGFR, GPR160, SPINT2) showed potential multivariate prognostic impact by entering the “forwards stepwise” multivariate Cox model for DFS. The upper half of patients according to the resulting “twelve-gene signature” had well over 90% 5y-DFS, whereas the lowest quartile had under 60% 5-y DFS. Several genes (incl. ERBB2, FOXC1) showed potential for a predictive impact regarding TC vs. EC-Doc by interaction analysis. Further details and perspectives for testing the robustness of these potential impacts will be presented at the meeting.

Conclusions

To our knowledge, these are the first results from a prospective, adjuvant taxane-based trial regarding molecular predictors of anthracycline efficacy and PAM-50-based prognostic factors in early TNBC. ERBB2 expression, but not HER2-enriched subtype, was predictive for A-benefit in HER2-negative BC. Molecular heterogeneity of TNBC beyond basal-like vs. non-basal-like subtype is clinically relevant and should be considered for patient stratification in ongoing trials with combination therapy. The identified prognostic gene signature should be validated in the WSG-ADAPT-TN and other TNBC trials.

Citation Format: Gluz O, Liedtke C, Prat A, Christgen M, Gebauer D, Kates R, Pelz E, Clemens M, Warm M, Aktas B, Kuemmel S, Pare L, Krabisch P, Kreipe HH, Wuerstlein R, Nitz U, Harbeck N. Genomic markers but not molecular subtypes provide prognostic impact and predict anthracycline efficacy in early triple-negative breast cancer: Results from the prospective WSG PlanB 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 P2-10-03.

Abstract P1-06-06: No age-related outcome disparities according to 21-gene recurrence score groups in early breast cancer patients treated by adjuvant chemotherapy in the prospective WSG PlanB trial

Background: Elderly breast cancer (BC) patients (pts) have been reported to have worse BC-related outcome than younger pts, even within clinical trials such as TEAM. Shak et al. recently showed in a large SEER data analysis that in the high 21-gene recurrence score (RS) group, older pts (>70y) receive less chemotherapy (CT) and have a worse BC-specific mortality than younger pts. Here, we therefore aimed to see whether there are age-related outcome disparities according to RS groups in pts receiving state-of-the-art CT in the prospective WSG PlanB trial.

Material and Methods: PlanB compared 6 cycles of anthracycline-free TC vs. standard anthracycline-taxane based CT (4xECà4xDoc) in patients with high risk pN0 (T2-4, G2-3, <35 years, or high uPA/PAI-1) or pN+ HER2- early BC. 21-gene assay was performed in all HR+ tumors and omission of chemotherapy (CT) recommended in RS≤11 HR+ pN0-1 BC. Final analysis for the CT randomization for RS 12-25 after 60 months median follow-up revealed similar 5-year DFS and OS outcomes for both CT arms (ASCO 2017).

Results: In all pts with luminal cancer and RS results (n=2577), there was an age-related significant difference in RS risk group assignment (p<0.0001): in young pts (<40y), 9.1% had RS≤11, 52.7% RS 12-25, and 38.2% RS>25; in pts 40-69 years, 18.3% had RS≤11, 61% RS 12-25, and 20.7%% RS>25; in elderly pts (>70y), 19.5% had RS≤11, 55.3% RS 12-25, and 25.2% RS>25. Among patients receiving chemotherapy, RS>25 vs. RS<25 was associated with significantly poorer DFS separately within the elderly subgroup (HR=3.03, 95%-CI [1.15-7.96]) and in those aged 40-69 years (HR=3.14, 95%-CI [2.18-4.52]); there were only nine events among patients <40y. In particular, among pts receiving CT with RS>25, there were no significant differences in DFS between any two of these three age groups.

Conclusion: A substantial percentage of elderly patients (> 70y) presents with high-risk luminal disease; these patients are candidates for CT. In PlanB, about 25% of elderly luminal BC patients had high-risk (RS>25) tumors. Nevertheless, after receiving modern adjuvant CT, their DFS was comparable to that of non-elderly pts with high-risk RS tumors. Consequently, older BC pts with high-risk luminal tumors who are fit enough to receive adjuvant CT should be treated according to guidelines in order to overcome age-dependent survival disparities which have been observed in registries for high-RS tumors.

Citation Format: Harbeck N, Gluz O, Wuerstlein R, Clemens M, Malter W, Reimer T, Nuding B, Stefek A, Pollmanns A, Augustin D, Uleer C, Lorenz-Salehi F, Shak S, Chao C, Christgen M, Kates R, Kreipe H, Nitz U. No age-related outcome disparities according to 21-gene recurrence score groups in early breast cancer patients treated by adjuvant chemotherapy in the prospective WSG PlanB trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-06-06.

Abstract P1-07-02: Chemotherapy (CT) decision in patients (pts) with node-positive (N+), ER+, early breast cancer (EBC) in the wake of new ASCO guideline – A different take on the evidence for the 21-gene recurrence score (RS) assay

Background: The use of molecular tools for prognosis and prediction of CT benefit in EBC has increased the complexity of decision making. The 21-gene RS (Oncotype DX) is included in the ASCO (2007) and NCCN guidelines (2006) for prognosis (risk of distant recurrence [DR]) and prediction of CT benefit in N0, ER+ EBC. In 2015, the NCCN added that the RS assay could be considered for select patients with 1-3 N+, ER+ EBC. Recently the ASCO BC biomarker/guideline group (J Clin Oncol 2016) advised that the “clinician should not use the 21-gene RS to guide decisions” and called the evidence quality “intermediate” and the recommendation “moderate” based on review of 2 N+ studies. It also advised no change in N+ clinical practice until the prospective SWOG S1007 study (RxPONDER) matures in several years. These discordant recommendations have led to major confusion among physicians, pts and payers. To address this controversy we herein report a comprehensive analysis of the body of evidence regarding the clinical utility of the RS in N+, ER+ EBC.

Methods: All published studies involving N+, ER+ EBC with RS data were analyzed by type of study design and category of trial (validation, supportive, decision impact, cost-effectiveness, and prospective outcomes).

Results: 30 studies provided clinical evidence supporting the value and utility of the RS in N+, ER+ pts. 7 studies employed a prospective-retrospective design or were prospective outcomes with clinical utility in >8000 N+ pts (Table). 23 additional studies assessed the impact of RS on CT decisions or cost-effectiveness.

Study in N+/ER+Type of studyNEndpoints/resultsSWOG S8814 (Lancet Oncol 2010)Pro-retro36710-year DFS and BCSS: RS predicts risk of DFS event, BC death, and CT benefit (none to slightly worse if very low risk RS and 1-3 N+)TransATAC (JCO 2010)Pro-retro3069-year DR: RS predicts risk of DR in pts treated with ET without CTECOG E2197 (JCO 2008)Pro-retro2325-year DR: RS predicts DR risk in CT+ET treated ptsNSABP B-28 (ASCO-BCS 2012)Pro-retro106510-year DRFI: RS predicts DR risk in CT+ET treated ptsPACS-01 (ASCO 2014)Pro-retro5305-year DRFI/DFS: RS predicts DR risk in CT+ET treated ptsSEER (npj BC 2016)Prospective outcomes46915-year BCSM: RS predicts BCSM; pts with RS <18 (Nmi, 1-3 N+) had 1.0% BCSMWSG PlanB (JCO 2016)Prospective outcomes1198 (1088 N1-3/110 N0)3-year DFS: 98.4% in high risk N0/N+ ER+, RS <12 group and 97.5% in RS 12-25 group (5-year DFS 94.0% in both RS groups)BCSM: BC-specific mortality; BCSS: BC-specific survival; DFS: disease free survival; DR: distant recurrence; DRFI: distant recurrence free interval; ET: endocrine therapy; Nmi: micrometastases; pro-retro: prospective-retrospective.

Conclusions: The 21-gene RS has now been studied in >10,000 N+, ER+ EBC pts across 30 studies worldwide, including 2 prospective outcomes studies in >5000 pts, confirming that the RS consistently identifies low risk 1-3 N+ pts in whom CT can effectively and safely be avoided. This evidence suggests that ER+ pts with few N+ and low RS should have a discussion of the pros and cons of adjuvant CT until the results of RxPONDER provide a definitive answer in several years.

Citation Format: Mamounas E, Goldstein L, Penault-Llorca F, Roche H, Gluz O, Harbeck N, Nitz U, O'Shaughnessy J, Albain K. Chemotherapy (CT) decision in patients (pts) with node-positive (N+), ER+, early breast cancer (EBC) in the wake of new ASCO guideline – A different take on the evidence for the 21-gene recurrence score (RS) assay [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 P1-07-02.

Abstract P5-14-01: Chemotherapy randomization of the EORTC 10041/ BIG 3-04 MINDACT (microarray in node-negative and 1 to 3 positive lymph node disease may avoid chemotherapy) trial

This abstract was withdrawn by the authors.

Comparison of prognostic and predictive impact of genomic or central grade and immunohistochemical subtypes or IHC4 in HR+/HER2- early breast cancer: WSG-AGO EC-Doc Trial

INTRODUCTION

Potential prognostic and predictive markers in early, intermediate-risk breast cancer (BC) include histological grade, Ki-67, genomic signatures, e.g. genomic grade index (GGI), and intrinsic subtypes. Their prognostic/predictive impact in hormone receptor (HR: ER and/or PR) positive/HER2- BC is controversial. WSG-AGO EC-Doc demonstrated superior event-free survival (EFS) in patients with 1-3 positive lymph node receiving epirubicin/cyclophosphamide-docetaxel (EC-Doc) versus 5-fluoruracil/epirubicin/cyclophosphamide (FEC).

METHODS

In a representative trial subset, we quantify concordance among factors used for clinical chemotherapy indication. We investigate the impact of central histology (n = 772), immunohistochemistry for intrinsic subtyping and IHC4, and dichotomous (GG) or continuous (GGI) genomic grade (n = 472) on patient outcome and benefit from taxane chemotherapy, focusing on HR+/HER2- patients (n = 459).

RESULTS

Concordance of local grade (LG) with central (CG) or genomic grade was modest. In HR+/HER2- patients, low (GG-1: 16%), equivocal (GG-EQ: 17%), and high (GG-3: 67%) GG were associated with respective 5-year EFS of 100%, 93%, and 85%. GGI was prognostic for EFS within all LG subgroups and within CG3, whereas IHC4 was prognostic only in CG3 tumors.In unselected and HR+/HER2- patients, CG3 and luminal-A-like subtype entered the multivariate EFS model, but not IHC4 or GG. In the whole population, continuous GGI entered the model [hazard ratio (H.R.) of 75th versus 25th = 2.79; P = 0.01], displacing luminal-A-like subtype; within HR+/HER2- (H.R. = 5.36; P < 0.001), GGI was the only remaining prognostic factor.In multivariate interaction analysis (including central and genomic grade), luminal-B-like subtype [HR+ and (Ki-67 ≥20% or HER2+)] was predictive for benefit of EC-Doc versus FEC in unselected but not in HR+/HER2- patients.

CONCLUSION

In the WSG-AGO EC-Doc trial for intermediate-risk BC, CG, intrinsic subtype (by IHC), and GG provide prognostic information. Continuous GGI (but not IHC4) adds prognostic information even when IHC subtype and CG are available. Finally, the high interobserver variability for histological grade and the still missing validation of Ki-67 preclude indicating or omitting adjuvant chemotherapy based on these single factors alone.

TRIAL REGISTRATION

The WSG-AGO/EC-Doc is registered at ClinicalTrials.gov, NCT02115204.

Abstract P2-07-01: Association of TILs with clinical parameters, recurrence score, and prognosis in patients with early HER2-negative breast cancer (BC) – A translational analysis of the prospective WSG planB trial

Introduction:

Tumor-infiltrating lymphocytes (TILs) have been associated with prognosis and with chemotherapy response among patients with BC, particularly in presence of high-risk features. The WSG planB trial randomized 2448 patients with HER2- N0/1 BC for comparison of anthracycline-free (6xTC) vs. standard anthracycline-taxane chemotherapy (4xEC-4xDoc). Recurrence Score® (RS) was incorporated for risk stratification in hormone receptor positive (HR+) BC. The present analysis focuses on the correlation of TILs with clinical/pathological parameters and their prognostic impact among planB patients.

Methods:

Stromal TILs were evaluated using a pathologist and two-observer approach. Three independent observers evaluated digital sections on H&E staining as previously suggested (Salgado et al., Ann Oncol. 2014); the median of the three values (TILmed) was used for statistical analysis. Spearman correlations of TILmed with clinical/pathological parameters (including central KI67 expression, quantitative ER measurements, nodal involvement, and RS) and univariate impact on event-free survival (EFS) were analyzed.

Results:

Our analysis included 300 patients with HR- and 1124 patients with HR+ HER2- BC. Both in HR- and HR+ BC, a significant association between TILmed and (i) central grading (correlation coefficient r=0.147, p=0.012 and r=0.195, p&lt;0.001, respectively) and (ii) central Ki67 expression (r=0.202, p=0.001 and r=0.152 and p&lt;0.001) was observed. Among HR+ cases, a significant association between TILmed and quantitative ER measurements (r=-0.412, p=0.041) and RS (r=0.190, p&lt;0.001) was found. Furthermore, univariate Cox analysis revealed a significant association between TILmed (coded as fractional rank) and event-free survival (EFS). The hazard ratio of 75th to 25th percentile was 1.58 (95%CI: 1.06-2.36, p=0.025). This impact was not separately significant in HR subgroups due to lack of events

Conclusion:

In this dataset, presence of stromal TILs was moderately associated with clinical features of high-risk breast cancer (including RS) and decreased EFS. TILs will be evaluated as a prognostic or predictive factor (in multivariate and subgroup analyses) when the outcome results are evaluated after prolonged follow up. Furthermore, an updated analysis including the complete planB dataset will be presented.

Citation Format: Liedtke C, Gluz O, Heinisch F, Feuerhake F, Kreipe HH, Clemens M, Nuding B, Kraemer S, Reimer T, Svedman C, Shak S, Nitz U, Kates RE, Harbeck N, Christgen M. Association of TILs with clinical parameters, recurrence score, and prognosis in patients with early HER2-negative breast cancer (BC) – A translational analysis of the prospective WSG planB trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-07-01.

Abstract P1-13-01: Comparison of 12 weeks neoadjuvant Nab-paclitaxel combined with carboplatinum vs. gemcitabine in triple- negative breast cancer: WSG-ADAPT TN randomized phase II trial

Background: Pathological complete response (pCR) is associated with improved prognosis in TNBC, but optimal chemotherapy remains unclear. Use of weekly nab- paclitaxel (Nab-Pac) vs. conventional paclitaxel and also addition of carboplatinum(Carbo) to anthracycline-taxane(A/T) containing chemotherapy results in significantly higher pCR rates in TNBC with unclear impact on survival and increased toxicity.

The ADAPT study seeks to compare Carbo vs. gemcitabine(Gem) added to nab- paclitaxel as a short 12-week A-free regimen. It also assesses efficacy in early responders vs. non-responders by 3-week proliferation and/or imaging response.

Methods: ADAPT TN compares 12-week neoadjuvant regimens: Carbo vs. Gem combined with Nab-Pac and aims to identify early-response markers for pCR (yPN0 and ypT0/is). TNBC patients (centrally confirmed ER/PR &lt;1%, HER2 neg.), cT1c- cT4c, cN0/+ were randomized to arm A (Nab-Pac 125/Gem 1000 d1,8 q3w) vs. B (Nab-Pac 125/Carbo AUC2 d1,8 q3w). Randomization was stratified by center and nodal status. The trial is powered for pCR comparison by therapy arm and by presence vs. absence of early response markers. Pre-planned interim analysis aimed to identify a dynamic biomarker, e.g. drop of 3-week Ki-67, and to validate trial assumptions.

Results: 336 patients were enrolled from 47 centers between 06/13-02/15 (n=182 ArmA: Nab-Pac/Gem and n=154 ArmB: Nab-Pac/Carbo). 90% and 95% completed therapy according to protocol respectively (n.s.). Median age was 50y. At baseline: A/B: 73% and 74%% had G3 tumors, median Ki-67 of 70% and 75%; 62.6% and 62.9%% had cT2-4c tumors, pN0 status prior to chemotherapy was confirmed in 50.5% and 50%, respectively.

pCR (ypT0/is/ypN0) was A: 28.7% and B: 45.9% (p&lt;0.001). Total pCR (ypT0/ypN0) was A: 25.8% and B: 45.2% respectively (p &lt;0.001).

Nab/Gem arm was associated with significantly higher frequency of dose reductions (20.6% vs. 11.9% (p=0.03), treatment related SAE's (13% vs. 5%, p=0.02), grade 3-4 infections (6.1% vs. 1.3%, p=0.04) and ALAT elevations (11.7 vs. 3.3%, p=0.01) compared to the Nab-Carbo arm.

Within the planned interim analysis (n=130: A/B: 69/61), baseline Ki-67 (Nab- Pac/Carbo arm), age&gt;50 years, and low cellularity (&lt;500 tumor cells and/or Ki-67≤10% in the 3-week biopsy) (Nab-Pac/Gem arm) were positively associated with pCR by logistic regression analysis (separately by therapy arm). In all patients, therapy arm itself was significant for pCR.

Validation of responder definitions for the whole study will be presented at the meeting.

Conclusions:

This is the first large randomized study comparing two short 12-week anthracycline- free regimens in unselected TNBC. Our results suggest superior efficacy and excellent toxicity of Nab-Pac/Carbo vs. Gem. Longer A/T-Carbo containing regimens render quite comparable pCR rates, thus overtreatment by 4xEC in unselected TNBC may be present in some patients. Early response criteria seem to differ according to regimen; their assessment may be impaired by substantial tumor necrosis already after the first therapy cycle.

Citation Format: Gluz O, Nitz U, Liedtke C, Christgen M, Sotlar K, Grischke EM, Forstbauer H, Braun M, Warm M, Hackmann J, Uleer C, Aktas B, Schumacher C, Bangemann N, Lindner C, Kuemmel S, Clemens M, Potenberg J, Staib P, Kohls A, Pelz E, Kates RE, Wuerstlein R, Kreipe HH, Harbeck N. Comparison of 12 weeks neoadjuvant Nab-paclitaxel combined with carboplatinum vs. gemcitabine in triple- negative breast cancer: WSG-ADAPT TN randomized phase II trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-13-01.

Final results from the prospective phase III WSG-ARA trial: impact of adjuvant darbepoetin alfa on event-free survival in early breast cancer

BACKGROUND

WSG-ARA plus trial evaluated the effect of adjuvant darbepoetin alfa (DA) on outcome in node positive primary breast cancer (BC).

PATIENTS AND METHODS

One thousand two hundred thirty-four patients were randomized to chemotherapy either with DA (DA+; n = 615) or without DA (DA-; n = 619). DA (500 µg q3w) was started at hemoglobin (Hb) levels <13.0 g/dl (<12 g/dl after DA label amendment) and stopped at Hb levels ≥14.0 g/dl (12 g/dl after label amendment). Primary efficacy end point was event-free survival (EFS); secondary end points were toxicity, quality of life (QoL) and overall survival (OS).

RESULTS

Venous thrombosis (DA+: 3.0%, DA-: 1.0%; P = 0.013) was significantly higher for DA+, but not pulmonary embolism (0.3% in both arms). Median Hb levels were stable in DA+ (12.6 g/dl) and decreased in DA- (11.7 g/dl). Hb levels >15 g/dl were reported in 0.8% of cycles. QoL parameters did not significantly differ between arms. At 39 months, DA had no significant impact on EFS (DA+: 89.3%, DA-: 87.5%; Plog-rank = 0.55) or OS (DA+: 95.5%, DA-: 95.4%; Plog-rank = 0.77).

CONCLUSIONS

DA treatment did not impact EFS or OS in routine adjuvant BC treatment.

Abstract P5-04-02: Biopsy of metastases impacts treatment choice and patient outcome in breast cancer – Final results of the WSG/DETECT PRIMET study

Background: Changes in tumor biology (e.g., hormone receptor (HR) / HER2 status or grading) between primary tumor (PT) and metastatic tissue (MT) could impact outcome and treatment choice following first recurrence in breast cancer (BC).

Methods: PRIMET is a prospectively planned, retrospective multicenter quality assurance study comparing BC phenotype in tissue from PT, involved lymph nodes (LN) of primary disease, and disease recurrence (DR). PRIMET comprises 635 patients from WSG and DETECT trial groups (11 centers), whose BC was diagnosed between 1980 and 2010; follow-up continued until mid-2012. Patients with unilateral primary BC suffering subsequent local-regional and / or distant DR (LDR / DDR) were included. Clinical data including ER, PR, HER2, and grade were obtained from a systematic chart review in PT and DR; in two centers, these factors were also measured in LN by central pathology. Dependence of post-recurrence survival (PRS) on changes in tumor biological factors was analyzed.

Results: Data from 635 patients (including 592 cM0, of whom 46% had LDR only) were available for analysis. Median follow-up in patients alive at analysis was 101 months. Considering cM0 patients, median overall survival (OS) was 176 months; median recurrence-free survival (RFS) was 48 months (DDR present: 45 months; LDR only: 50 months). Median PRS was 59 months (DDR present: 45 months; LDR only: 127 months). In patients with first DR within 18 months, median PRS was 29 months, in others 79 months. HR status in PT/MT was: 61.5% (+/+), 13.2% (+/-), 5.5% (-/+) 19.8% (-/-). Of the HR “switches” in either direction with LN biopsy available, about half already occurred in lymph nodes. HER2 status in PT/MT was: 14.6% (+/+), 6.7% (+/-), 14.9% (-/+) 63.8% (-/-). With LN biopsy available, most losses of HER2 overexpression were already observed in LN tissue, whereas acquired HER2 overexpression was observed in about half of LN biopsies. Triple negative (TN: HR-, HER2-) percentages were 74.4% (non-TN/non-TN), 9.0% (non-TN/TN), 6.1% (TN/non-TN), 10.5% (TN/TN).

Compared to HR+/+, loss of HR+ status (HR+/-) was significantly associated with poorer PRS (hazard ratio: 1.62; p = 0.01). Significantly better PRS was associated with a switch from G3 to G1/2 (hazard ratio: 0.47; p = 0.02). Tumors that switched to TN or that lost HER2 overexpression showed trends toward poorer PRS. Persistent TN was associated with poorer PRS than other combinations.

Among patients with DDR, metastasis in bone only was associated with better PRS than primary or visceral (CNS, lung, liver, etc.) metastasis. Among patients with visceral metastasis, negative HR status in metastasis was associated with poorer survival than in HR+/+ not only for HR-/- (p = 0.02), but also for HR+/- (p = 0.04).

Conclusions:

Tumor biology of primary and metastatic tissue differed in a substantial fraction of patients (HR: 19%; HER2: 22%, TN: 18%); more than half of all changes occurred already in LN. Status changes particularly loss of HR+ status, had significant prognostic impact. We can expect a switch in HR or HER2 status (or both) in about 38% of metastatic tissue biopsies, with presumably important clinical therapeutic consequences, in particular regarding targeted therapies.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-04-02.

Abstract P6-05-11: Run-in phase of prospective WSG-ADAPT HR+/HER2- trial demonstrates feasibility of early endocrine sensitivity prediction by recurrence score and conventional parameters in clinical routine

Background: Despite promising evidence regarding outcome prediction, endocrine sensitivity, as determined by proliferation response to short-term preoperative endocrine therapy, is currently not included in adjuvant chemotherapy decisions in early HR+/HER2- breast cancer (BC).

Methods: The prospective WSG-ADAPT HR+/HER2- trial includes early BC patients with 0-3 positive LN who are candidates for adjuvant chemotherapy based on clinical-pathological criteria alone; it aims to spare chemotherapy in a substantial proportion utilizing a combination of genomic assessment by Oncotype DX and endocrine sensitivity testing. All patients received 3-week preoperative endocrine induction therapy (ET): aromatase inhibitors (AI) if postmenopausal, tamoxifen if premenopausal. Patients with low (0-11) Recurrence Score (RS) or intermediate RS (12-25) and ET response (centrally tested, post-therapy Ki-67 &lt;10%) are recommended to forego adjuvant chemotherapy (“low-risk” patients). Distribution of RS, responder percentages in each group, and impacts of RS, ET regimen, and initial Ki-67 on post-therapy Ki-67 are reported here.

Results: As of 6/2013, 380 patients from 30 study centers had been enrolled in the ADAPT HR+/HER2- trial. Median age was 54 years. At first pre-planned analysis (5/2013), paired Ki-67 measurements (pre-/post-therapy) were available in 241 patients; RS was available in 208 cases (201 with paired Ki-67). RS was low in 21.6%, intermediate in 57.7%, and high in 20.7%; the respective risk group responder percentages (post-treatment Ki 67 &lt;10%) were 84.1%, 73.9%, and 40.0% (p&lt;0.001 when comparing low/intermediate vs. high, chi-square). In particular, these percentages support the pre-trial estimate of &gt;70% endocrine responders in the intermediate genomic risk group, who could potentially be spared adjuvant chemotherapy. Median Ki 67 level decreases (as percentage of pre-treatment value) were 25% in premenopausal patients (tamoxifen, n = 101) vs. 75% in postmenopausal patients (AI, n = 115) (p&lt;0.001, Mann-Whitney); median decreases by RS group were similar, 61% (low), 53% (intermediate) and 56% (high), respectively (p = 0.81, Kruskal-Wallis). In linear regression, pre-treatment Ki-67, endocrine regimen/menopausal status, and RS were all independent predictors for post-treatment Ki 67. Final run-in-phase analysis and validation will be presented after completion of endocrine induction therapy in 400 patients.

Conclusions: The Run-In Phase of the WSG ADAPT HR+/HER2- trial confirms trial design estimates of RS and proliferation response to induction ET. It indicates that the multicenter prospective ADAPT concept combining static and dynamic biomarker assessment for individualized therapy decisions in early BC is feasible. Proliferation response was strongly associated with therapy group (AI/post-menopausal vs. tamoxifen/pre-menopausal). Survival non-inferiority of intermediate Recurrence Score proliferation responders vs. low Recurrence Score patients (active control) will be tested in the ADAPT main phase to determine if adjuvant chemotherapy can be spared in 70% of patients with 0-3 positive LN classified as “intermediate risk” by conventional factors.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-05-11.

Abstract S3-4: Ten year follow-up analysis of intense dose-dense adjuvant ETC (epirubicin (E), paclitaxel (T) and cyclophosphamide (C)) confirms superior DFS and OS benefit in comparison to conventional dosed chemotherapy in high-risk breast cancer patients with ≥ 4 positive lymph nodes

Background: The 5-year analysis of adjuvant chemotherapy with intense dose-dense (IDD) ETC had shown a significant improved DFS (HR 0.72; p &lt; 0.001) and OS (HR 0.76; p = 0.29) in comparison with conventional dosed chemotherapy (J Clin Oncol 28: 2874–2880, 2010). In contrast to other dose-dense trials the ETC regimen is dose-dense and dose-intensified. Long-term results are essential to evaluate the impact of dose-dense chemotherapy in the adjuvant treatment of breast cancer patients (pts). We now report the final analysis of DFS, OS, and long-term safety including the application of epoetin alfa after 10 years of follow-up.

Patients and Methods: A multi-center phase-III trial of the German AGO Breast Study Group recruited 1284 pts from 12/98 until 4/03. Pts below 65 years of age were eligible if at least 4 axillary lymph nodes were infiltrated. In the experimental arm, pts were assigned to receive three courses each of epirubicin (150 mg/m2), paclitaxel (225 mg/m2) and cyclophosphamide (2500 mg/m2) at 2-week intervals (q2w) (ETC) with G-CSF support (5µg/kg/SC day 3–10). In the standard arm 4 courses of conventional dosed epirubicin/cyclophosphamide (90/600 mg/m2) followed by 4 courses of paclitaxel (175 mg/m2) were given (EC→T). All cycles were administered in 3-week intervals without growth factor support. A second randomization ± epoetin alfa was performed in the IDD-ETC arm only (150IU/kg/sc three times weekly) to reduce the number of red blood cells (RBC's) transfusion and to evaluate the impact of epoetin alfa on DFS and OS in the adjuvant setting.

Results: 58% and 42% of the pts presented with 4–9 and ≥ 10 positive nodes with a median number of 8 involved nodes. The median age was 51 years and median follow-up was 122 months. We observed 604 DFS events (282 with IDD ETC; 322 with EC→T) (p = 0.00014, one-sided; HR 0.74; 95% CI, 0.63 to 0.87). IDD ETC improved DFS irrespective of nodal status, HER2 and ER status. 446 pts. have died (201 events in the IDD ETC arm vs. 245 events in the standard arm). 10 year OS rates were 69% with IDD ETC and 59% with EC→ T (p = 0.0007; two-sided; HR, 0.72; 95% CI, 0.60–0.87). Nine cases of acute myeloid leukemia or myelodysplastic syndrome occurred in the IDD ETC arm vs. two cases in the standard arm. 28% of pts in the IDD ETC arm vs. 13% in the IDD ETC arm plus epoetin alfa (p &lt; 0.0001) received RBC's transfusions. There was no difference between the IDD ETC arm alone and the IDD ETC + epoetin alfa arm regarding 10-year DFS and OS ((57% vs. 55% (p = 0.69) and 70% vs. 68% (p = 0.45)).

Conclusion: Intense dose-dense ETC remains significantly superior compared to standard chemotherapy after 10 years of follow-up. The risk of secondary leukemia/MDS in the IDD ETC arm (1.3% of pts) is comparable to that of the Cancadian CEF regimen. The prevention of RBC's transfusions and anemia by the application of epoetin alfa in the IDD ETC-arm had no impact on DFS and OS. IDD ETC is a highly effective and safe regimen in the adjuvant treatment of high-risk breast cancer pts.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr S3-4.

PD07-06: Adjuvant Chemotherapy with or without Darbepoetin alpha in Node-Positive Breast Cancer: Survival and Quality of Life Analysis from the Prospective Randomized WSG ARA Plus Trial

Background: Darbepoetin alpha (ARA) is currently used to reduce chemotherapy-associated anemia (CAA) rates in various solid tumors. A possible negative impact of ARA on patient survival has been suggested in some clinical trials. The objective of the prospective randomized phase III ARA Plus trial is to compare the survival effect of darbepoetin alpha use (ARA+/ARA-) in combination with modern standard adjuvant chemotherapy targeting guideline-recommended Hb-levels in high-risk breast cancer (BC).

Methods: ARA Plus compared 6 cycles T75A50C500 q3w or 6 cycles F500E100C500 q3w (at discretion of each center) in patients with node positive BC (aged 18–65 years). Patients were randomized to darbepoetin (ARA+) 500 μg q3w until completion of radiotherapy or to standard supportive care (ARA-). ARA was started at Hb-levels ≤13 g/dL (amendment 01/2008: Hb ≤12 g/dL) and stopped at &gt;14 g/dL (&gt;12 g/dL). Primary endpoint is event-free survival (EFS: relapses, death without disease evidence, second malignancy). Overall survival (OS), toxicity, Hb-levels and quality of life are secondary endpoints. Survival analysis was planned after 7 years of study duration. EFS was tested using χ2-test (α=0.05) with a statistical power of β=80% and log-rank test. Quality of life was measured using FACT questionnaires at beginning of therapy, mid, end of therapy, and at 1 year afterwards.

Results: 1234 pts (616 ARA+/618 ARA-) from 70 centres in Germany were randomized between 01/04 and 06/08. 1198 intent to treat patients (ITT) were analysed (1096 TAC; 102 CEF). Baseline characteristics were well balanced in ARA+ and ARA- arms: median age 53/53 years; tumor size 2.4/2.4cm; number of + LN 3/3; HR+ 80%/ 83.5%, G3 40.7%/36.7%. Toxicity data have been reported earlier (SABCS 2008).

At median follow up of 40 months, 168 events (81 ARA+, 83 ARA-) and 134 relapses (65 ARA+, 69 ARA-) were reported. There was no significant difference in 3-year EFS between ARA+ and ARA- arms (89.2% vs. 87.6%, p=0.97, χ2-test). 37 deaths were reported in the ARA- and 36 in the ARA+ arm. 3-year OS was 95.4% and 95.1% for ARA+ and ARA-, respectively (p=0.85). Only nodal involvement (≥4 vs. 1–3), negative HR, tumor size &gt;2 cm and G3 were significant survival predictors by multivariate analysis. Unplanned retrospective analysis revealed better EFS for ARA+ vs. ARA- in HR- (p=0.05), and no difference in HR+ group (p=0.6). In ARA+ patients, Hb-levels were stable over the whole treatment period with rare overstimulation. In ARA- patients, Hb-levels decreased during therapy (median of all cycles ARA+/ARA-: 12.5/11.6 g/dL). There was no correlation between mean Hb-levels and survival in either study arm.

There were no significant differences in mean FACT scores changes (general, anemia, cognitive) from begin to end of therapy in either study arm. More detailed analyses are ongoing.

Conclusions: To date, the WSG ARA plus trial is the only prospectively randomized trial in early high-risk BC exclusively focusing on the impact of adjuvant ARA on patient outcome. Supportive administration of ARA appears to be safe and to have no significant survival effect when used in combination with TAC or CEF according to current guidelines.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD07-06.

P1-06-03: Predictive Value of HER2, Topoisomerase-II (Topo-II) and Tissue Inhibitor of Metalloproteinases (TIMP-1) for Efficacy of Taxane-Based Chemotherapy in Intermediate Risk Breast Cancer – Results from the EC-Doc Trial

Background: Despite extensive research, there is still no consensus on optimal predictors for use of taxane-based chemotherapy (cht) in early breast cancer. Some studies have revealed HER2 as a significant predictive marker for efficacy of taxanes and anthracyclines. TIMP-1 and Topo-II are reported to be predictive for anthracycline efficacy. In our previous reports, both Ki-67≥20% and central G3 status emerged as significant predictors for taxane benefit. We have now compared HER2 and Topo-II (as protein expression and gene amplification) and TIMP-1 immunoreactivity as well as factor combinations (HT (HER2/TIMP-1) and 2T (Topo-II/TIMP-1) regarding their predictive value for benefit from taxane-based cht.

Methods: The EC-Doc trial randomized 1950 patients with 1–3 positive LN to 6x CEF/CMF vs. 4xEC-4xDoc. Significantly better DFS and OS favoring EC-Doc have been previously reported (Nitz et al., SABCS 2008). Protein expression and gene amplification data as well central histology/grade were available for 772 patients. Survival analysis was performed using Cox proportional hazards and Kaplan-Meier statistics. Analysis of HER2 survival impact status was prospectively planned.

Results: The entire and the investigated study populations did not differ regarding baseline characteristics. After median follow up of 64 months, both DFS (5y 90% vs. 80%, p=0.006) and OS (5y 95% vs. 92%, p=0.022) rates significantly favored EC-Doc vs. CEF in this cohort as well. HER2 over-expression (3+ and/or FISH≥2.0) was reported in 158 tumors (20%), Topo-II aberration (deletion or amplification) was reported in 78 (49.4%) HER2+ and in 83 (13.6%) HER2−negative tumors; 496 tumors were classified as TIMP-1 immunoreactive (65.2%). None of these factors were significantly prognostic for EFS in this collective. Regarding DFS, EC-Doc was strongly superior to FEC in HER2+ tumors (HR=0.29, 95%CI: 0.12−0.7, p=0.006) but not in HER2− tumors (p=0.18). In Topo-II aberrated tumors, the benefit of EC-Doc was remarkably strong (HR=0.28, 95% CI: 0.11−0.69, p=0.006), whereas the benefit was not significant in Topo-II normal tumors (p=0.16), which comprise more than ¾ of the total. In contrast, Topo-II protein overexpression (&gt;10%) was not associated with a stronger benefit in either subgroup. The superiority of EC-Doc to FEC was significant in the larger group of TIMP-1 immunoreactive tumors (HR=0.57, p=0.025) but not in TIMP-1 negative tumors (p=0.14), similar behavior was seen in “HT” and “2T” subgroups (significance with HR about 0.5 in the “+” subgroups). In a multivariate model for DFS including age, tumor size, Ki-67, central grade, HR, HER2, TOPO_II aberration, TIMP-1 status, therapy and interactions of all these factors with therapy arm, the only significant therapy interaction was that of (high) Ki-67 (HR=0.76, 95% CI: 0.59−0.98, p=0.03); significant main effects in this model were age, central grade, and Ki-67.

Conclusions: These data suggest predictive significance for Topo-II aberration, TIMP immunoreactivity and HER2 over-expression as well as a multivariate predictive significance of high Ki-67 for enhanced benefit of taxane-based cht.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-06-03.

P5-18-03: First Interim Toxicity Analysis of the Randomized Phase III WSG Plan B Trial Comparing 4xEC-4xDoc Versus 6xTC in Breast Cancer Patients with HER2 Negative Breast Cancer (BC)

Background: Anthracycline-taxane based adjuvant chemotherapy (cht) is considered standard in node-positive and high-risk node-negative BC. However, retrospective analyses suggest that in HER2−BC, benefit from anthracyclines may not outweigh acute and long term toxicities. Recurrence Score (RS) identifies patients who are not candidates for cht based on their low relapse risk, as well as minimal, if any, benefit of cht. The WSG Plan B trial investigates anthracycline-free cht in HER2− BC and is the first trial in Europe prospectively incorporating RS for decision making regarding adjuvant cht in both N0 and N+ BC.

Methods: Plan B trial randomizes HER2− BC patients with high-risk N0 (at least one risk factor: ≥pT2; negative HR status; G2-3; age ≤35 years old; high uPA/PAI-1) or N+ disease to 6xTC (Docetaxel 75Cyclophosphomide600) vs. 4xEC (Epirubicin90Cyclophosphomide600)-4xDocetaxel100 G-CSF prophylaxis is recommended according to current ASCO guidelines. The statistical design previews n=2.448 randomized to cht; patients with HR+ BC, N0-3 and a RS ≤11 receive endocrine therapy only.

Results: From April 2009 to June 2011, 3037 patients have been recruited and 2296 randomized (TC/EC-Doc: 1146/1150; age &lt;65 years old: 900/911; ≥65 years old: 246/239). From the patients with HR+ disease (n=2368) 18% had a RS 0–11, 61% a RS 12–25 and 21% a RS ≥ 25. In patients with 0–3 positive LN and RS of 0–11 (n=329) who opted for no cht 257 are in the observational arm. In the group with an intermediate risk (RS 12–25) 14% drop outs before start of cht have been reported. In 1172 fully monitored patients 22 toxicity-related therapy stops have been reported in the TC and 34 in the EC-Doc arm (p=0.12). 614 serious adverse events (SAE) have been reported (299 TC vs. 315 EC-Doc). There is no difference in patients &lt;65 years old (TC vs. EC-Doc: 218/218), but slightly more SAE's in patients ≥65 years old treated by EC-Doc (97 vs. 81, p=0.13).

The most frequent SAEs were: leucopenia, febrile neutropenia (TC/EC-Doc:37 (3.3%)/31 (2.7%), n.s.), infections and heart/vascular events (TC/EC-Doc 29/40, n.s.). In patients ≥65 years old, there is a trend towards more febrile neutropenia (13 vs. 5; p=0.06) in the TC, and more severe mucositis/diarrhea/nausea (3 vs. 15; p=0.007) and heart/vascular events (5 vs. 14; p=0.06) in the EC-Doc arm. There were 5 therapy related deaths (TC 5 (0.4%)/EC-Doc 0, p=0.03); 3 in patients &lt;65 years, 2 in patients ≥65 years (4 due to sepsis, 1 due to cardiac failure).

Detailed data on relationship between the protocol specified, RS-guided treatment assignment and toxicity, and use of G-CSF support will be updated for the meeting.

Conclusions: The Plan-B trial is one of the largest randomized phase III trials currently evaluating anthracycline-free adjuvant cht in HER2− BC. The cht administered within the study was generally well tolerated, but higher number of treatment-related deaths has been observed within the TC arm. The short term toxicity profile seems be different between both study arms, particularly in patients &gt;65 years old. On the basis of prognosis as determined by RS, cht has been spared after a shared decision process in a substantial group of patients.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-18-03.

Abstract P2-09-14: Evidence for Predictive and Prognostic Impact of Molecular Classification in Taxane-Based Chemotherapy in Intermediate Risk Breast Cancer — An Analysis of the WSG EC-Doc Trial

Background: Patients with hormone receptor positive breast cancer (BC) and 1-3 positive lymph nodes (LN) belong to the intermediate risk-group. Among these patients chemoendocrine therapy may be considered. The prognostic role of molecular breast cancer subgroups and their predictive impact regarding taxane-and anthracycline based chemotherapy is unclear. This analysis evaluated the ability of molecular subtypes to predict outcome after standard FEC or EC-Doc chemotherapy in pts with 1-3 positive LN.

Methods: The EC-Doc trial randomized 2012 patients with 1-3 positive LN to 6x FEC/CMF vs. 4x EC followed by 4 x docetaxel (Doc). Significantly better DFS and OS in favor of EC-Doc was reported previously (Nitz et al., SABCS 2008). Protein expression data and central histology/grade (G) were available for 772 patients (Control n=390; EC-Doc n=382). Protein expression was measured on tissue micro arrays for ER, PR, Her2 (both IHC/FISH), Ki-67, Ck 5/6, and EGFR. Molecular subgroups were classified using ki-67 cutt-off of 13.25 % (Cheang et al. JNCI 2009). Results: There was no difference in baseline characteristics (age, LN, grade, tumor size, HR) between the entire ITT-study population and the investigated cohort of 772 pts. There were significantly more G 3 tumors in the basal and Her2 group and more G 1/2 tumors in the luminal A cohort. Distribution of molecular subtypes is as follows:

- Luminal A: HR+ (ER and/or PR+), low KI-67 and Her2-: 26.1%

- Luminal B: HR+ and either Ki-67 high or Her2+: 44.8%

- Her2: HR-and Her2+: 10.9%

- Triple negative (TN) basal-like ER/PR/Her2- ; Ck 5/6+ and/or EGFR+: 11.8%

- TN non-basal-like: TNBC; both Ck 5/6 and EGFR-: 6.4%

After median follow up of 64 months, both DFS (5y 90% vs. 80%, p=0.006) and OS (5y 95% vs. 92%, p=0.022) rates also significantly favored EC-Doc vs. FEC in this cohort. DFS rates were highest in luminal A and lowest in TN basal-like tumors.

In univariate analysis a significant benefit of EC-DOC vs. FEC for DFS is seen in luminal B patients (p=0.004; HR=0.41; (0.22-0.77)). EC-Doc was also better than FEC in HR-patients who were not “basal-like (p=.057; HR=0.385 (0.14 — 1.07).

In multivariate analysis including age, nodal status, tumor size, molecular subtypes, and chemotherapy regimen age, luminal A subtype, and interaction of EC-Doc and luminal B subtype (HR=0.44) influenced significantly DFS survival. Conclusions: These data provide evidence that molecular subtypes are associated with both different levels of benefit from EC-Doc and different DFS within each treatment group. These retrospective results will be validated within the prospective WSG PlanB trial.

Table/Figure 1: multivariate model for DFS

Tabid Parameters bssdciated with benefitfrctm EC-Dgccompared to CEF in a multivariate tnofiel tor DFS

Abstract P4-06-22: Persistent Triple-Negative Phenotype Is Associated with Poorest Outcome among Patients with Metastatic Breast Cancer (BC) - Results of the Retrospective Multicenter PriMet Study Comparing Molecular BC Phenotypes in Primary Tumors and Corresponding Recurrences

Background: Patients with triple negative (TN) breast cancer (BC), defined by lack of both ER/PR expression and HER2 overexpression, have an unfavorable prognosis. Although phenotype changes between primary tumor (PT) and disease recurrence (DR) have been described, their clinical significance is still unclear.

Methods: We conducted PriMet, a retrospective multicenter (n=11) study to compare BC phenotype in PT and corresponding DR. Inclusion criteria comprised (1) unilateral BC with subsequent/synchronous local/regional/distant DR and (2) immunohistochemical confirmation of DR. Our aim was to (a) evaluate discordance rates between PT/DR, (b) find predictors for discordance, and (c) analyze the impact of discordance on patient outcome.

Results: 436 patients were entered into PriMet; 414 had no evidence of primary metastatic disease (M0). Median follow-up in patients alive at time of analysis was 73. 1 (4.4-293.6) months. Triple receptor status for PT and DR was available in 377 patients; 68 patients (18.0 %) showed TNBC in PT, 40 patients (10.6 %) had TNBC in both PT and DR (i.e. TNBC persistence); 28 patients (7.4 %) changed from TNBC to non-TNBC (15 became HER2 positive (4.0 %)). Status changes for ER and PR were significantly positively associated (P&lt;0.001). Patients with either persistent TNBC or non-TNBC had a median age at diagnosis of 52.0 compared to 55.5 yrs for patients with discordant TN status (p=0.04). Compared to differing constellations, persistent TNBC was associated with higher tumor grade (p=0.018) as well as with both decreased disease-free survival (DFS) (see figure) and post-recurrence survival (PRS) in M0 patients. In multivariate analysis containing pT stage, nodal stage, tumor grade in PT, TNBC in PT and TNBC persistence, TNBC persistence remained significantly associated with decreased DFS and PRS.

Conclusion: PriMet provides substantial evidence regarding potential phenotype changes in PT vs. DR and underlines the importance of immunohistochemical DR verification even in initially TN disease. TNBC persistence was significantly associated with adverse patient outcome.