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 <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<0.001). Total pCR (ypT0/ypN0) was A: 25.8% and B: 45.2% respectively (p <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>50 years, and low cellularity (<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 P4-04-06: Systematic analysis of molecular subgroups and age in patients with breast cancer

Background: Breast cancer (BC) molecular subgroups show significant differences with regard to prognosis. Similarly, young age at diagnosis is significantly associated with an unfavorable prognosis.

Methods: Our aim was to analyze the association between BC molecular subtypes and age at diagnosis. Publically available gene expression data (Affymetrix U133A) of 3488 BC patients was analyzed using MAS5.0 and pooled into a single database. Age information was available for 2604 of the patients (74.7%). Of a total of 579 cases with TNBC, 394 samples with most comparable array data were selected to avoid batch effects as previosly described. Age information was available for 309 of these 394 patients (78.4%). Significance Analysis of Microarrays (SAM) was performed to identify genes with differential expression according to age at diagnosis in these 309 patients with TNBC.

Results: Patients &lt;40 years significantly more often presented with triple negative BC compared to patients 40-50 and &gt;50 (34.8 vs. 25.4 vs. 17.3%, respectively). In contrast, a luminal A subtype was diagnosed less often in patients &lt; 40 yrs (20.6 vs. 31.9 vs. 41.1%, respectively). Although we observed significant differences for EFS according to i) age at diagnosis and ii) molecular subtype, EFS differences between patients of distinct age were only modest after stratification for molecular subtype. Among patients with TNBC, 134 genes were upregulated and 627 genes were downregulated in patients &lt; 40 yrs compared to patients ≥ 40 yrs (median FDR &lt; 4%). Several of the downregulated genes in young TNBC patients belong to a metagene for the molecular-apocrine subtype of TNBC and several upregulated genes represent cell cycle genes. However, the effects for individual genes were rather small. Conclusion: The frequency of molecular subgroups differs with age at diagnosis. Young age at diagnosis is significantly associated with adverse prognosis. Within the group of TNBC patients young age is associated with high proliferation and a basal-like phenotype and inversely correlated with the molecular-apocrine subtype of TNBC.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-04-06.

Abstract P3-14-01: Features of neoadjuvant and adjuvant chemotherapy in breast cancer – A population-based study on 39404 patients

Background: Neoadjuvant chemotherapy (NACT) is increasingly used globally in clinical trials for breast cancer patients. In Germany, NACT has been implemented as a standard option of care for almost a decade. In a population-based benchmark cohort study, the West German Breast Center (WBC) recorded approximately 50% of all breast cancer cases diagnosed in Germany between 2007 and 2010. We compare baseline and treatment pattern of patients treated either with adjuvant (ACT) or NACT.

Methods: Approx. 200 accredited breast centers treated 115169 primary breast cancer patients of whom 32609 received ACT and 6795 NACT. Pathological complete response (pCR) was stated if no invasive and no non-invasive tumor residues (ypT0 ypN0) were detected. Follow up information was available for 55% of patients.

Results: Use of NACT increased from 16.4% in 2007 to 19.1% in 2010 (p&lt;.0001). Patients treated with NACT were younger, had higher clinical nodal involvement, fewer lobular-invasive cancers, more undifferentiated, hormone-receptor-negative, and HER2-positive cancers, and more multicentric tumors compared to patients treated with ACT (all p&lt;0.002). 34% of patients in the NACT group had cT3/4 tumors compared to 7.7% of pT3/4 tumors in the ACT group. cN0 status was twice as frequent (70.6% vs 37.7%, p&lt;.0001) whereas pN0 status was reported less frequently (47.4% vs 51.4%, p&lt;0.0001) in the ACT and NACT group, respectively. Time between diagnosis and start of systemic treatment or surgery was in median 12 (range 1-902) and 22 (range 1-721) days in the ACT and NACT group, respectively (p&lt;.0001). 66.2% and 91.4% of patients received ACT and NACT with a taxane, respectively (p&lt;.0001). 9.7% and 37.5% of patients receiving treatment for &gt; = 18 weeks, respectively. 35.2% and 69.9% of patients with HER2-positive tumors received adjuvant or neoadjuvant trastuzumab, respectively (p&lt;.0001). 21.7% and 31.4% of patients were treated in ACT or NACT clinical trials, respectively (p&lt;.0001). Breast conservation was possible in 69.4% and 55.2% in the ACT and NACT group, respectively (p&lt;.0001). 30.5% and 37.5% needed two or more surgical interventions in the ACT and NACT group, respectively (p&lt;.0001).

Multivariable logistic regression analysis confirmed taxane- and trastuzumab-based treatment, study participation, age, histologic type, grading, and hormone-receptor status as independent predictors of pCR. pCR rate was not dependent on the time between diagnosis and start of treatment or the time between end of chemotherapy and surgery.

In univariate analysis patients receiving NACT showed a 4-year overall survival rate of 78%, compared to 92% in patients receiving ACT (p&lt;.0001). However, patients with a pCR after NACT showed a comparable survival to patients in the ACT group, whereas patients without a pCR showed a 4-year overall survival rate of 76%. In the hormone-receptor-positive/HER2-positive and even more in the triple-negative subgroup, survival of patients with a pCR appeared better than in patients with ACT.

Conclusion: In this population-based study, NACT was used in patients with unfavorable risk factors and was more intense than ACT. Outcome of patients with pCR after NACT was similar and in aggressive tumor subtypes even better than after ACT.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-14-01.

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.

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.