Efficacy of Endocrine Therapy Plus Trastuzumab and Pertuzumab vs De-escalated Chemotherapy in Patients with Hormone Receptor-Positive/ERBB2-Positive Early Breast Cancer: The Neoadjuvant WSG-TP-II Randomized Clinical Trial

Importance

Combination of chemotherapy with (dual) ERBB2 blockade is considered standard in hormone receptor (HR)-positive/ERBB2-positive early breast cancer (EBC). Despite some promising data on endocrine therapy (ET) combination with dual ERBB2 blockade in HR-positive/ERBB2-positive BC, to our knowledge, no prospective comparison of neoadjuvant chemotherapy vs ET plus ERBB2 blockade in particular with focus on molecular markers has yet been performed.

Objective

To determine whether neoadjuvant de-escalated chemotherapy is superior to endocrine therapy, both in combination with pertuzumab and trastuzumab, in a highly heterogeneous HR-positive/ERBB2-positive EBC.

Design, Setting, and Participants

This prospective, multicenter, neoadjuvant randomized clinical trial allocated 207 patients with centrally confirmed estrogen receptor-positive and/or progesterone receptor-positive (>1%) HR-positive/ERBB2-positive EBC to 12 weeks of standard ET (n = 100) vs paclitaxel (n = 107) plus trastuzumab and pertuzumab. A total of 186 patients were required to detect a statistically significant difference in pathological complete response (pCR) (assumptions: 19% absolute difference in pCR; power, ≥80%; 1-sided Fisher exact test, 2.5% significance level).

Interventions

Standard ET (aromatase inhibitor or tamoxifen) or paclitaxel, 80 mg/m2, weekly plus trastuzumab and pertuzumab every 21 days.

Main Outcomes and Measures

The primary end point was pCR (ypT0/is, ypN0). Secondary end points included safety, translational research, and health-related quality of life. Omission of further chemotherapy was allowed in patients with pCR. PAM50 analysis was performed on baseline tumor biopsies.

Results

Of the 207 patients included (median [range] age, 53 [25-83] years), 121 (58%) had cT2 to cT4 tumors, and 58 (28%) had clinically node-positive EBC. The pCR rate in the ET plus trastuzumab and pertuzumab arm was 23.7% (95% CI, 15.7%-33.4%) vs 56.4% (95% CI, 46.2%-66.3%) in the paclitaxel plus trastuzumab and pertuzumab arm (odds ratio, 0.24; 95% CI, 0.12-0.46; P < .001). Both immunohistochemical ERBB2 score of 3 or higher and ERBB2-enriched subtype were independent predictors for pCR in both arms. Paclitaxel was superior to ET only in the first through third quartiles but not in the highest ERBB2 quartile by messenger RNA. In contrast with the paclitaxel plus trastuzumab and pertuzumab arm, no decrease in health-related quality of life after 12 weeks was observed in the ET plus trastuzumab and pertuzumab arm.

Conclusions and Relevance

The WSG-TP-II randomized clinical trial is, to our knowledge, the first prospective trial comparing 2 neoadjuvant de-escalation treatments in HR-positive/ERBB2-positive EBC and demonstrated an excellent pCR rate after 12 weeks of paclitaxel plus trastuzumab and pertuzumab that was clearly superior to the pCR rate after ET plus trastuzumab and pertuzumab.

Trial Registration

ClinicalTrials.gov Identifier: NCT03272477.

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.

Impact of RNA Signatures on pCR and Survival after 12-Week Neoadjuvant Pertuzumab plus Trastuzumab with or without Paclitaxel in the WSG-ADAPT HER2+/HR- Trial

PURPOSE

To identify associations of biological signatures and stromal tumor-infiltrating lymphocytes (sTIL) with pathological complete response (pCR; ypT0 ypN0) and survival in the Phase II WSG-ADAPT HER2+/HR- trial (NCT01817452).

EXPERIMENTAL DESIGN

Patients with cT1-cT4c, cN0-3 HER2+/HR- early breast cancer (EBC) were randomized to pertuzumab+trastuzumab (P+T, n = 92) or P+T+paclitaxel (n = 42). Gene expression signatures were analyzed in baseline biopsies using NanoString Breast Cancer 360 panel (n = 117); baseline and on-treatment (week 3) sTIL levels were available in 119 and 76 patients, respectively. Impacts of standardized gene expression signatures on pCR and invasive disease-free survival (iDFS) were estimated by logistic and Cox regression.

RESULTS

In all patients, ERBB2 [OR, 1.70; 95% confidence interval (CI), 1.08-2.67] and estrogen receptor (ER) signaling (OR, 1.72; 95% CI, 1.13-2.61) were favorable, whereas PTEN (OR, 0.57; 95% CI, 0.38-0.87) was unfavorable for pCR. After 60 months median follow-up, 13 invasive events occurred (P+T: n = 11, P+T+paclitaxel: n = 2), none following pCR. Gene signatures related to immune response (IR) and ER signaling were favorable for iDFS, all with similar HR about 0.43-0.55. These patterns were even more prominent in the neoadjuvant chemotherapy-free group, where additionally BRCAness signature was unfavorable (HR, 2.00; 95% CI, 1.04-3.84). IR signatures were strongly intercorrelated. sTILs (baseline/week 3/change) were not associated with pCR or iDFS, though baseline sTILs correlated positively with IR signatures.

CONCLUSIONS

Distinct gene signatures were associated with pCR versus iDFS in HER2+/HR- EBC. The potential role of IR in preventing recurrence suggests that patients with upregulated IR signatures could be candidates for de-escalation concepts in HER2+ EBC.

De-escalated Neoadjuvant Chemotherapy in Early Triple-Negative Breast Cancer (TNBC): Impact of Molecular Markers and Final Survival Analysis of the WSG-ADAPT-TN Trial

PURPOSE

Although optimal treatment in early triple-negative breast cancer (TNBC) remains unclear, de-escalated chemotherapy appears to be an option in selected patients within this aggressive subtype. Previous studies have identified several pro-immune factors as prognostic markers in TNBC, but their predictive impact regarding different chemotherapy strategies is still controversial.

EXPERIMENTAL DESIGN

ADAPT-TN is a randomized neoadjuvant multicenter phase II trial in early patients with TNBC (n = 336) who were randomized to 12 weeks of nab-paclitaxel 125 mg/m2 + gemcitabine or carboplatin d 1,8 q3w. Omission of further (neo-) adjuvant chemotherapy was allowed only in patients with pathological complete response [pCR, primary endpoint (ypT0/is, ypN0)]. Secondary invasive/distant disease-free and overall survival (i/dDFS, OS) and translational research objectives included quantification of a predictive impact of markers regarding selection for chemotherapy de-escalation, measured by gene expression of 119 genes (including PAM50 subtype) by nCounter platform and stromal tumor-infiltrating lymphocytes (sTIL).

RESULTS

After 60 months of median follow-up, 12-week-pCR was favorably associated (HR, 0.24; P = 0.001) with 5y-iDFS of 90.6% versus 62.8%. No survival advantage of carboplatin use was observed, despite a higher pCR rate [HR, 1.04; 95% confidence interval (CI), 0.68-1.59]. Additional anthracycline-containing chemotherapy was not associated with a significant iDFS advantage in pCR patients (HR, 1.29; 95% CI, 0.41-4.02). Beyond pCR rate, nodal status and high sTILs were independently associated with better iDFS, dDFS, and OS by multivariable analysis.

CONCLUSIONS

Short de-escalated neoadjuvant taxane/platinum-based combination therapy appears to be a promising strategy in early TNBC for using pCR rate as an early decision point for further therapy (de-) escalation together with node-negative status and high sTILs. See related commentary by Sharma, p. 4840.

Concordance and clinical impact of ER, PR, HER2 expression by local and central immunohistochemistry versus RT-PCR in HR+/HER2- early breast cancer (EBC): Results from the ADAPT trial

536

Background: We evaluated concordance of ER, PR and HER2 status between local, central, and RT-PCR/mRNA assessments and its clinical impact in the ADAPT trial collective in HR+ HER2- EBC (NCT01779206). Particularly, validity of borderline ER-positivity (expression level 1-10%) has great clinical relevance as treatment concepts between luminal-like and triple negative (TNBC) EBC differ substantially. Methods: Patients (pts) with clinically high-risk HR+/HER2- EBC (ER and/or PR >1%) were initially treated by 3 (+/-1) weeks of endocrine therapy (ET) before surgery or sequential core biopsy (CB) and then allocated to an ET-alone or chemotherapy (ET) trial, depending on risk and endocrine response. OncotypeDX (incl. RT-PCR for ER, PR, HER2) and central IHC for ER, PR, HER2 were performed on the initial 1.CB. ER-low cohort was defined as 1-10% expression by local OR central lab (ASCO-CAP). Cox models were used to estimate hazard ratios. Results: In ADAPT, 5149 pts from 81 centers in Germany with locally ER and/or PR positive (known quantitative levels) EBC were screened 2012-2018. Median follow-up was 59 months. For ER (positive vs. negative), overall concordance measured as agreement (κ) was high between all three assessments: Local vs. central IHC: 99.3% (κ = 0.45), RT-PCR vs. central IHC: 99% (κ = 0.48). Concordance was lower for PR: RT-PCR vs. central IHC: 90.5% (κ = 0.58), local vs. central IHC: 93.1% (κ = 0.56). 3% were centrally found as HER2+ in 1.CB (73% of them were negative by RT-PCR) and/or 2. Sample. Regarding HER2-low status (1+ or 2+ but ISH negative), concordance between local and central IHC was only 53.8% (κ = 0.09). Of all pts, only 2% (n=109; n=85 with both measurements available) had low ER expression (1-10%) by either local or central pathology. Only 9 of them were concordantly identified as ER-low (11%); 8/58 (14%) ER-low by local lab had TNBC by central lab. 17/47 ER-low cases (36.2%) with known post-endocrine Ki67post had Ki67post <10% vs. 59.7% in ER>10%. 41.8% of ER-low cases had RS<25 vs. 76.7% in ER>10%. All cases with ER <10% by both assessments and those with Ki-67≥40% had RS >25. We observed worse iDFS (HR 1.91, p=0.034) in the ER-low group vs. ER>10%. Conclusions: Although we have confirmed high agreement between local and central IHC and RT-PCR for ER, PR, HER2 assessment in locally HR+/HER2- EBC, there are still a few clinically relevant discordances. Regarding HER2-low status, standardization and quality assurance are needed if this becomes clinically relevant. Treatment of the heterogeneous ER-low group as TNBC appears reasonable only if “ER-low” is confirmed by a second assessment and in cases with Ki-67>40%. Preoperative ET response assessment may be helpful if an endocrine-based therapy concept is intended. Clinical trial information: NCT01779206.

Adjuvant dynamic marker-adjusted personalized therapy comparing endocrine therapy plus ribociclib versus chemotherapy in intermediate-risk HR+/HER2- early breast cancer: ADAPTcycle

TPS609

Background: The WSG ADAPT trial program focusses on individualization of (neo)-adjuvant decision-making in EBC in a subtype-specific manner. Clinical feasibility of the WSG ADAPT trial goals - early response assessment and subtype-specific therapy tailoring to those patients (pts) who are most likely to benefit - has recently been confirmed by the 5-years survival data of the ADAPT HR+/HER2- clinical trial. Methods: WSG-ADAPTcycle is a prospective, multi-center, interventional, two-arm, (neo)adjuvant, non-blinded, randomized, controlled phase III trial (NCT04055493) investigating whether treatment with the CDK4/6 inhibitor ribociclib (600mg/day) together with ET is superior to standard-chemotherapy (CT) in intermediate-risk HR+/HER2- EBC. Definition of intermediate-risk is either based on Oncotype DX and endocrine responder status (measured by Ki67-response after 2-4 weeks of induction endocrine therapy (ET)) or on low-intermediate baseline Ki67 and high estrogen receptor (ER)/progesterone receptor (PR)-expression (Dowsett et al. NPJ Breast Cancer 2020). Co-primary endpoints are DFS and dDFS. It is planned to screen 5600 pts and to randomize 1670 pts (1002 to ribociclib + ET; 668 to standard CT followed by ET). Study start was in July 2019 (88 sites, enrollment period 42 months) and until date of submission, 3079 pts have been screened and 811 randomized (490 ribociclib / 321 CT). Pre-/postmenopausal pts with histologically confirmed invasive HR+/HER2- EBC with high clinical risk (cT2-4 or Ki-67 20% or G3 or cN+) are eligible if they fulfil the ADAPT intermediate-risk criteria: Recurrence Score (RS) ≤25 plus several risk factors and poor ET responder, RS >25 and ET-responder in p/cN0-1 pts, or RS ≤25 with c/pN2-3 in ET-responder. Direct randomization of premenopausal patients (irrespective of ET-response) with c/pN0 and RS 16-25 or c/pN1 with RS 0-25 is allowed according to investigator´s decision; however, based on the ADAPT results, ET+ovarian function suppression alone is strongly recommended in ET-responders. Treatment duration is 2 years for the ribociclib + aromatase inhibitor (AI) (premenopausal: AI + GnRH)-arm and 16-24 weeks for the CT-arm; neoadjuvant or adjuvant treatment is allowed. The minimum 5-year follow-up phase includes standard adjuvant ET. ePROs are collected using CANKADO; ECG monitoring is performed using a novel eHealth method. Translational analyses: Tumor tissue will be collected prior to ET, after at least 3 weeks of ET, if residual tumor is diagnosed (neoadjuvant treatment), and at recurrence, to identify potential resistance markers. Exploratory tissue biomarker research will be conducted to assess alterations in molecular markers. In addition, ctDNA/ctRNA from optional blood samples will be assessed for mutations and gene expression relevant for HR+/HER2- EBC. Clinical trial information: NCT04055493.

Immune Markers and Tumor-Related Processes Predict Neoadjuvant Therapy Response in the WSG-ADAPT HER2-Positive/Hormone Receptor-Positive Trial in Early Breast Cancer

Prognostic or predictive biomarkers in HER2-positive early breast cancer (EBC) may inform treatment optimization. The ADAPT HER2-positive/hormone receptor-positive phase II trial (NCT01779206) demonstrated pathological complete response (pCR) rates of ~40% following de-escalated treatment with 12 weeks neoadjuvant ado-trastuzumab emtansine (T-DM1) ± endocrine therapy. In this exploratory analysis, we evaluated potential early predictors of response to neoadjuvant therapy. The effects of PIK3CA mutations and immune (CD8 and PD-L1) and apoptotic markers (BCL2 and MCL1) on pCR rates were assessed, along with intrinsic BC subtypes. Immune response and pCR were lower in PIK3CA-mutated tumors compared with wildtype. Increased BCL2 at baseline in all patients and at Cycle 2 in the T-DM1 arms was associated with lower pCR. In the T-DM1 arms only, the HER2-enriched subtype was associated with increased pCR rate (54% vs. 28%). These findings support further prospective pCR-driven de-escalation studies in patients with HER2-positive EBC.

Prognostic impact of recurrence score, endocrine response and clinical-pathological factors in high-risk luminal breast cancer: Results from the WSG-ADAPT HR+/HER2- chemotherapy trial

504

Background: In HR+/HER2- N0-1 early BC, postmenopausal patients (pts) with RS™ > 25 and a substantial proportion of premenopausal pts seem to benefit from addition of adjuvant chemotherapy (CT) to endocrine therapy (ET). However, the magnitude of absolute benefit from this treatment intensification seems to depend on clinical-pathological and biological prognostic factors. For the first time, we present outcome from the CT part of the prospective phase III WSG-ADAPT HR+/HER- trial combining both static (RS in baseline core biopsy (CB) and dynamic (Ki67 response) biomarkers to optimize adjuvant therapy in luminal EBC. Methods: Pts with clinically high-risk HR+/HER2- EBC (cT2-4 OR clinically N+ OR G3 OR Ki67>15%) were initially treated by 3 (+/-1) weeks of standard ET (postmenopausal: mostly AI; premenopausal: TAM) before surgery or sequential CB. Pts with cN2-3 or G3/Ki67>40% were randomized directly to the CT trial. pN0-1 pts with RS0-11 OR RS12-25/ET-response (central Ki67postendocrine<10%) received ET alone; the remaining high-risk cohort was randomized to the CT trial: (neo)adjuvant dose-dense CT (4xPaclitaxelà4xEC q2w vs. 8xNab-Paclitaxel q1wà4xEC q2w) followed by ET. Primary endpoint is efficacy comparison of CT schedules for survival; secondary endpoints reported here involve impacts of key prognostic factors on survival. Kaplan-Meier and Cox proportional hazard models were used to estimate survival curves and hazard ratios. For this analysis, subgroups free of selection bias by RS/ET-response were defined. Results: 5625 pts were screened and 4621 (ITT) entered the trial. After 4.9y median follow-up, higher baseline and post-endocrine Ki-67 levels were associated with poorer iDFS (both p < 0.001). In the CT cohort (n = 2331), higher RS, nodal status, and tumor size were generally associated with poorer iDFS. However, iDFS differed between N1 and N0 status only among younger pts (<50 years). In pts with >4 positive LN (n = 390), lower RS was associated with improved iDFS (RS0-11 vs RS > 25: plog-rank= 0.016, 5y-iDFS 90% vs. 64%). In pts with RS > 25 (n = 965), low Ki67postendocrine, N0 status, and c/pT1 status were associated with improved iDFS. In particular, ET-responders had higher 5y-iDFS (84%) than ET-non-responders (77%; plog-rank= 0.040). Younger patients (<50 years old) with N0-1 RS 12-25/ ET-non-responders treated by CT had non-significantly poorer 5-year iDFS (89%) compared to those with ET-response treated by ET only (92%) (plog-rank= 0.249). Conclusion: First results from the prospective high risk cohort from a large prospective phase III ADAPT trial provide evidence for good prognosis in some pts with >4 positive LN and e.g. low RS. Moreover combination of lower post-endocrine Ki-67 and limited tumor burden may be a promising criterion for CT de-escalation strategies even in patients with high RS. Clinical trial information: NCT01779206.

Pathological complete response rate and survival in patients with BRCA-associated triple-negative breast cancer after 12 weeks of de-escalated neoadjuvant chemotherapy: Translational results of the WSG-ADAPT TN randomized phase II trial (NCT01815242)

579

Background: The phase II trial WSG-ADAPT TN randomized triple-negative breast cancer (TNBC) patients to receive 12 weeks of neoadjuvant nab-paclitaxel (nab-pac) combined with carboplatin (carbo) vs gemcitabine (gem) and showed a substantial improvement of pathological complete response (pCR: ypT0/is, ypN0) with carbo (45.9% vs 28.7%). pCR had a strong favorable impact on iDFS after 3-year follow-up. Distribution of tumor mutations in BC-associated genes and impact of BRCA mutation status on pCR and outcome are analyzed here. Methods: NGS-based mutational analysis of BRCA1/2 and 18 further (potentially) BC-associated genes was performed on DNA derived from pretreatment FFPE samples (gem: n = 158, carbo: n = 108) using a customized gene panel. Variants with a variant fraction of ≥5% were included and classified according to IARC and ENIGMA guidelines. Results: In 42 of the 266 analyzed samples, at least one deleterious BRCA1/2-variant was found (15.8%; BRCA1 n = 37, BRCA2 n = 3, BRCA1+ BRCA2 n = 2) one of which displayed an additional STK11-mutation. In the BRCA1/2-negative cohort, a mutation in one of 14 further analyzed (potential) BC-risk genes was found in 19 samples (7.1%; BARD1 n = 3, CHEK2 n = 2, CDH1 n = 2, FANCM n = 3, PALB2 n = 5, RAD50 n = 1, RAD51C n = 1, RAD51D n = 1, XRCC2 n = 1; no deleterious mutations were found in ATM, BRIP1, MRE11A, NBN). At least one deleterious variant in TP53, PIK3CA, PTEN or MAP3K1 was seen in 89.1% (n = 237; TP53 n = 233, PIK3CA n = 22 PTEN n = 15, MAP3K1 n = 1). In 22 samples (8.3%) no deleterious mutation was identified in the analyzed genes. Overall, patients with tumor BRCA mutation (carbo n = 14, gem n = 28) had 45.2% vs 34.4% pCR (OR = 1.58, 95%-CI: 0.81-3.07, p =.18) without a mutation. pCR in the small group with mutation receiving carbo (n = 14) was 64.3% vs. 34.5% in all others (OR = 3.41, 95%-CI: 1.11-10.50; p =.03); direct comparison to BRCA-positive patients receiving gem (n = 28, 35.7%, OR = 3.2, 95%-CI: 0.85-12.36, p = 0.079) did not reach statistical significance. The results suggest that the strong favorable impact of pCR on iDFS is preserved even among BRCA-positive patients (n = 42, p =.07), as well as in the BRCA-negative subgroup (p <.001). No evidence for a predictive impact of BRCA mutation on efficacy of 4xEC additional chemotherapy was seen overall or within pCR subgroups. Conclusions: Twelve weeks of neoadjuvant nab-pac/carbo is a highly effective anthracycline-free regimen that leads to an excellent pCR-rate of 64% in tumor BRCA1/2-mutated cases. BRC A1/2 mutation status could support this de-escalation strategy in early TNBC, but further prospective validation of survival impacts in larger cohorts and with longer follow up is needed. More detailed survival analyses will be presented at the meeting. Clinical trial information: NCT01815242.

De-escalated neoadjuvant pertuzumab+trastuzumab with or without paclitaxel weekly in HR-/HER2+ early breast cancer: ADAPT-HR-/HER2+ biomarker and survival results

503

Background: Optimal use of de-escalated, particularly chemotherapy(CT)-free, neoadjuvant regimens in HER2+ early breast cancer (EBC) is currently unclear as there are limited survival data so far. In ADAPT-HR-/HER2+, we previously showed an excellent pCR rate of 90% after 12-week neoadjuvant paclitaxel (Pac) +pertuzumab (P) +trastuzumab (T) and a substantial and clinically meaningful pCR rate of 34% after P+T alone in HR-/HER2+ EBC. Here, we present first survival data. Methods: The prospective multicenter WSG-ADAPT-HR-/HER2+ phase II-trial is part of the ADAPT-umbrella protocol. Patients with cT1-cT4c, cN0-3 HR-/HER2+ EBC (n = 134) were randomized to 4 cycles of P+T +/- pac d1,8,15 q3w. All tumors were HR-negative (ER and PR < 1%) and HER2-positive (central lab, i.e., 2+ FISH positive or 3+ by immunohistochemistry. Primary endpoint was pCR (ypT0/is/ypN0); omission of further CT was allowed in pts with pCR. Trial objective was to compare pCR in P+T+pac arm vs. early responders in P+T arm (defined as low cellularity and/or Ki67 decrease >30% after 3 weeks). The trial was stopped early due to the observed pCR superiority in the P+T+pac arm. Secondary endpoints included safety, 5-y (distant)-DFS, OS and translational research. Cox-regression analysis was applied. PAM50 subtype was assessed using the BC360 panel. Results: 134 patients were randomized to P+T (n = 92) or P+T+pac (n = 42). 60% of tumors were cT2-4, 42% clinically node-positive. After a median follow-up of 5 years, no significant differences between study arms were observed regarding DFS, dDFS, and OS; only 13 iDFS events (7 dDFS) were observed in the whole ITT population. pCR (vs. non-pCR) after the 12-week study treatment (irrespective of study arm) was strongly associated with improved iDFS (5y DFS 98.5% vs. 82%, HR = 0.14, 95% CI 0.03-0.64). Of the 69 patients with pCR, 39 (56.5%) received no further CT (P+T arm: n = 9, 29% vs. (P+T+pac arm n = 30, 79%); only 1 distant relapse (1.4%) was observed in these patients. In the CT-free P+T arm, no pCR was observed in patients with low HER2 expression (IHC 1+/2+ and FISH positive) and/or basal-like subtype by PAM50 (n = 17, 19%). In the total study population, low HER2 expression and/or no early response was strongly associated with worse dDFS (p =.029) and iDFS (p =.068). No new safety signals were observed. Conclusions: For the first time, we have shown both excellent pCR and survival in patients treated by de-escalated neoadjuvant CT+P+T irrespective of further CT use in a prospective multicenter study. Investigation of CT-free regimens may need to be focussed on selected patients only (e.g. with high HER2 expression/non-basal-like tumors). In ADAPT HR-/HER2+, early pCR after only 12 weeks of neoadjuvant P+T+pac was strongly associated with improved outcome and may thus serve as a predictive clinical marker for further treatment (de)-escalation. Clinical trial information: NCT01779206.

ADAPTlate: A randomized, controlled, open-label, phase III trial on adjuvant dynamic marker—Adjusted personalized therapy comparing abemaciclib combined with standard adjuvant endocrine therapy versus standard adjuvant endocrine therapy in (clinical or genomic) high-risk, HR+/HER2- early breast cancer

TPS598

Background: The WSG ADAPT trial program addresses the individualization of (neo)adj. decision-making in EBC. The ADAPT umbrella trial established early predictive molecular surrogate markers for response after a 3-wk endocrine treatment (ET) to omit chemotherapy (CT) in a cohort of early high-risk HR+/HER2- pts. ADAPTlate seeks to improve adj. therapy for pts. at high risk for late disease recurrence, who completed definite locoregional therapy (with / without (neo-)adj. CT) and are under adj. ET. This high-risk population does not derive optimal benefit from standard ET, develops secondary ET resistance, and late recurrences. Methods: Prospective, multi-center, interventional, two-arm, open, randomized, controlled adj. phase III trial (NCT04565054) to investigate additional benefit from 2 years of the CDK4/6-inhibitor abemaciclib combined with ET compared to ET alone in pts. with high-risk HR+/HER2- EBC. Abemaciclib demonstrated to improve outcome in metastatic BC and even in EBC when given as part of primary therapy. Primary objective is to demonstrate superiority of iDFS of abemaciclib + ET vs. standard ET. Secondary objectives include OS, dDFS, occurrence of CNS metastases, QoL, and translational research. Recruitment started in 9/2020 to screen 1250 pts. and to randomize 903 pts. in a ratio 3:2. Until date of submission, 33 pts. were screened and 22 randomized. Pre-/postmenopausal pts. with histologically confirmed invasive HR+/HER2- EBC, 2-6 y after primary diagnosis, with either known high clinical risk (c/pN 2-3 OR high CTS score in pN 0-1 OR non-pCR after neoadj. CT in cN 1 or G3 tumors OR G3 and Ki-67 ≥ 40% in pN 0-1) or known high genomic risk (RS >25 in c/pN 0, RS >18 in c/pN 1 OR high risk Prosigna, EPclin or Mammaprint in pN 0-1) or intermediate clinical, but unknown genomic risk (luminal B-like (G3 or Ki-67 ≥20%) in c/pN 0-1 AND either RS >25 in c/pN 0 or RS >18 in c/p N1 in screening) will be eligible. Treatment duration is 2 years for the abemaciclib + ET (premenopausal: AI + GnRH) arm, followed by at least 3-6 years ET alone. Pts. in control arm will receive 5-8-years ET at investigator´s choice. ePROs are collected using CANKADO. Translational analyses: Exploratory tissue biomarker research to assess alterations in molecular markers. Liquid biopsies (CTC/ctDNA/ctRNA) will be assessed for mutations and gene expression relevant for HR+/HER2- EBC using an appropriate technology at time of testing. Conclusions: ADAPTlate seeks to evaluate whether Abemaciclib + ET is superior to ET alone in pts. with clinical or genomic high-risk EBC even 2-6 years after initial diagnosis. Translational research aims at assessing potential mechanisms of resistance to endocrine and/or CDK4/6 targeted therapy. Clinical trial information: NCT04565054.

Immune cell composition and functional marker dynamics from multiplexed immunohistochemistry to predict response to neoadjuvant chemotherapy in the WSG-ADAPT-TN trial

BACKGROUND

The association of early changes in the immune infiltrate during neoadjuvant chemotherapy (NACT) with pathological complete response (pCR) in triple-negative breast cancer (TNBC) remains unexplored.

METHODS

Multiplexed immunohistochemistry was performed in matched tumor biopsies obtained at baseline and after 3 weeks of NACT from 66 patients from the West German Study Group Adjuvant Dynamic Marker-Adjusted Personalized Therapy Trial Optimizing Risk Assessment and Therapy Response Prediction in Early Breast Cancer - Triple Negative Breast Cancer (WSG-ADAPT-TN) trial. Association between CD4, CD8, CD73, T cells, PD1-positive CD4 and CD8 cells, and PDL1 levels in stroma and/or tumor at baseline, week 3 and 3-week change with pCR was evaluated with univariable logistic regression.

RESULTS

Compared with no change in immune cell composition and functional markers, transition from 'cold' to 'hot' (below-median and above-median marker level at baseline, respectively) suggested higher pCR rates for PD1-positive CD4 (tumor: OR=1.55, 95% CI 0.45 to 5.42; stroma: OR=2.65, 95% CI 0.65 to 10.71) and PD1-positive CD8 infiltrates (tumor: OR=1.77, 95% CI 0.60 to 5.20; stroma: OR=1.25, 95% CI 0.41 to 3.84; tumor+stroma: OR=1.62, 95% CI 0.51 to 5.12). No pCR was observed after 'hot-to-cold' transition in PD1-positive CD8 cells. pCR rates appeared lower after hot-to-cold transitions in T cells (tumor: OR=0.26, 95% CI 0.03 to 2.34; stroma: OR=0.35, 95% CI 0.04 to 3.25; tumor+stroma: OR=0.00, 95% CI 0.00 to 1.04) and PD1-positive CD4 cells (tumor: OR=0.60, 95% CI 0.11 to 3.35; stroma: OR=0.22, 95% CI 0.03 to 1.92; tumor+stroma: OR=0.32, 95% CI 0.04 to 2.94). Higher pCR rates collated with 'altered' distribution (levels below-median and above-median in tumor and stroma, respectively) of T cell (OR=3.50, 95% CI 0.84 to 14.56) and PD1-positive CD4 cells (OR=4.50, 95% CI 1.01 to 20.14).

CONCLUSION

Our exploratory findings indicate that comprehensive analysis of early immune infiltrate dynamics complements currently investigated predictive markers for pCR and may have a potential to improve guidance for individualized de-escalation/escalation strategies in TNBC.

Abstract OT-01-02: Adaptlate -a randomized, controlled, open-label, phase-iii trial on adjuvant dynamic marker - adjusted personalized therapy comparing abemaciclib combined with standard adjuvant endocrine therapy versus standard adjuvant endocrine therapy in (clinical or genomic) high risk, hr+/her2- early breast cancer

Goals: The WSG ADAPT trial program is one of the first new generation trials addressing the issue of individualization of (neo)-adjuvant decision-making in early breast cancer (EBC) in a subtype-specific manner. The first WSG ADAPT umbrella trial (NCT01779206) aimed to establish early predictive molecular surrogate markers for response after a short 3-week induction treatment and to omit chemotherapy in a large cohort of early high risk HR+/HER2- patients. The aim of the ADAPTlate phase-III-trial is to improve adjuvant therapy for patients at high risk for late disease recurrence, who have completed definite locoregional therapy (with or without neoadjuvant or adjuvant chemotherapy) and are under adjuvant endocrine treatment. This high-risk population does not derive optimal benefit from standard ET, often develops secondary resistance against ET and consequently late recurrences. With ADAPTlate, it is planned to evaluate whether patients with high-risk EBC derive additional benefit from adding abemaciclib to ET even 2-6 year after their initial diagnosis. Abemaciclib has been shown to improve outcome in metastatic breast cancer and recently, even in early breast cancer when given as part of primary therapy. Methods: WSG-ADAPTcycle is a prospective, multi-center, interventional, two-arm, non-blinded, randomized, controlled adjuvant phase III trial (NCT not yet assigned). It investigates whether patients with HR+/HER2- EBC identified as high-risk during screening (based on clinical or genomic risk) derive additional benefit from 2 years of the CDK4/6 inhibitor abemaciclib combined with ET compared to ET alone. Starting Q3 2020 (enrollment 36 months, 50 sites), 1250 patients will be screened and 903 randomized in a ratio 3:2 (602 to abemaciclib + ET; 301 to standard ET). Pre-/postmenopausal patients with histologically confirmed invasive HR+/HER2- EBC and 2-6 years after primary diagnosis, with either known high clinical risk (c/pN 2-3 OR high CTS score in pN 0-1 OR non-pCR after neoadjuvant chemotherapy in cN 1 or G3 tumors OR G3 and Ki-67 ≥ 40% in pN 0-1) or known high genomic risk (Oncotype Dx® / RS &gt;25 in c/pN 0, RS &gt;18 in c/pN 1 OR high risk Prosigna®, EPclin® or Mammaprint® in pN 0-1) or intermediate clinical, but unknown genomic risk (luminal B-like (G3 or Ki-67 ≥20%) in c/pN 0-1 AND Oncotype DX® in screening either RS &gt;25 in c/pN 0 or RS &gt;18 in c/p N1) will be eligible. Treatment duration is 2 years for the interventional abemaciclib + ET (premenopausal: AI+GnRH) arm, followed by at least 3-6 years ET alone. Patients in control arm will receive 5-8-years ET at investigator´s choice. ePROs are collected using CANKADO. Primary objective is to demonstrate superiority of invasive disease-free survival (iDFS) of abemaciclib + ET vs. standard ET. Secondary objectives include overall survival (OS), distant disease-free survival (dDFS), occurrence of CNS metastases, quality of life (EORTC QLQ-C30, QLQ-BR23, EQ-5D-5L) and translational research. Translational analyses: Exploratory tissue biomarker research will be conducted to assess alterations in molecular markers (e.g., ESR1, PIK3CA, CCND1, CDKN2A, RB1). In addition, ctDNA/ctRNA from optional blood samples will be assessed for mutations and gene expression relevant for HR+/HER2- EBC using the most appropriate technology at the time of testing. Conclusions: ADAPTlate seeks to evaluate whether enhancing ET with a CDK 4/6 inhibitor is superior to ET alone in patients with clinical or genomic high risk EBC even 2-6 years after their initial diagnosis. Translational research aims at assessing potential mechanisms of resistance to endocrine and/or CDK4/6 targeted therapy.

Citation Format: Oleg Gluz, Tom Degenhardt, Norbert Marschner, Matthias Christgen, Hans Heinrich Kreipe, Ulrike Nitz, Ronald Kates, Timo Schinkoethe, Monika Graeser, Rachel Würstlein, Sherko Kuemmel, Nadia Harbeck, West German Study Group. Adaptlate -a randomized, controlled, open-label, phase-iii trial on adjuvant dynamic marker - adjusted personalized therapy comparing abemaciclib combined with standard adjuvant endocrine therapy versus standard adjuvant endocrine therapy in (clinical or genomic) high risk, hr+/her2- early breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr OT-01-02.

ADAPTcycle: Adjuvant dynamic marker-adjusted personalized therapy (ADAPT) comparing endocrine therapy plus ribociclib versus chemotherapy in intermediate-risk HR+/HER2- early breast cancer (EBC)

TPS601

Background: The WSG ADAPT trial program represents the concept of individualization of (neo)-adjuvant decision-making in EBC in a subtype-specific manner. The first WSG ADAPT umbrella trial aimed to establish early predictive molecular surrogate markers for response after a short 3-week induction treatment. The goals of the WSG ADAPT trial program are early response assessment and subtype-specific therapy tailoring to those patients who are most likely to benefit. Methods: WSG-ADAPTcycle is a prospective, multi-center, interventional, two-arm, open-label, (neo)adjuvant, non-blinded, randomized, controlled phase III trial (NCT04055493). It investigates whether patients (pts.) with HR+/HER2- EBC identified during screening as intermediate risk (based on Oncotype DX and response to 3 weeks of preoperative endocrine therapy [ET]) derive additional benefit from 2 years of the CDK4/6 inhibitor ribociclib combined with ET compared to chemotherapy (CT) (followed by standard ET). Co-primary endpoints are disease-free survival (DFS) and distant DFS. It is planned to screen 5600 pts and to randomize 1670 pts in a 3:2 ratio (ribociclib + ET/CT). Study start was in July 2019 (80 sites, enrollment period 36 months) and until date of submission, 180 pts. have been screened and 40 randomized. Pts with HR+/HER2- EBC with clinically enhanced risk (cT2-4 or Ki67 20% or G3 or cN+) are eligible if they fulfill the ADAPT intermediate-risk group criteria: either Recurrence Score (RS) ≤25 and Ki67postendocrine>10%, RS >25 and Ki67postendocrine<10% in p/cN0-1 pts, or RS ≤25 and Ki67postendocrine<10% in c/pN2-3 pts. Treatment duration is 2 years for the ribociclib + ET (premenopausal: AI + GnRH) arm and 16-24 weeks for the CT arm; treatment is possible either in the neoadjuvant (ET + ribociclib duration 16 – 32 weeks) or adjuvant setting. ePROs are collected using CANKADO; ECG monitoring is performed using a novel cardiology-supported CANKADO-based eHealth method. Translational analyses: Exploratory tissue biomarker research will be conducted to assess alterations in molecular markers. In addition, ctDNA/ctRNA from optional blood samples will be assessed for mutations and gene expression. Conclusions: ADAPTcycle seeks to evaluate whether endocrine-based therapy with ET and a CDK 4/6 inhibitor is superior to CT followed by ET in patients with luminal EBC who may be undertreated with ET alone (based on either lack of endocrine responsiveness or high tumor burden). Clinical trial information: 2018-003749-40 .

De-escalated chemotherapy versus endocrine therapy plus pertuzumab+ trastuzumab for HR+/HER2+ early breast cancer (BC): First efficacy results from the neoadjuvant WSG-TP-II study

515

Background: HR+/HER2+ breast cancer (BC) is a distinct entity associated with better prognosis compared to HR-/HER2+ BC. However, combination of chemotherapy (CT) with (dual) anti-HER2 blockade is standard in HER2+ early BC (EBC), irrespective of HR-status. Despite of some promising data on combination of endocrine therapy (ET) with dual anti-HER2 blockade in EBC and metastatic HR+/HER2+ BC, no prospective comparison of neoadjuvant CT vs. ET + dual HER2-blockade has yet been performed. Methods: In the prospective WSG TP-II phase II-trial (NCT03272477; Sponsor: Palleos GmbH, Wiesbaden, Germany), 207 patients (pts) (257 screened; 40 centers) with centrally confirmed HR+/HER2+ EBC were randomized to 12 weeks of standard ET (n=100) vs. paclitaxel 80 mg/m2 weekly (n=107) +trastuzumab+pertuzumab q3w for all pts. Primary endpoint was pCR (ypT0/is/ypN0). Secondary endpoints include safety, disease-free and overall survival, translational research, and quality of life (QoL). Omission of further CT was allowed in all pts with pCR; dual HER2-blockade was administered in the adjuvant setting in all pts. Results: Baseline characteristics were well balanced between the arms. Median age was 53 years; 58% had cT2-4, 28% had cN+; 43% had G3 tumors. pCR data were available in 198 pts (ET: n=96; Pac: n=102). pCR was observed in 24% (95% CI: 16-34%) with ET+T+P vs. 57% (95% CI:47-67%) with Pac+T+P (OR 0.24, 95% CI: 0-0.46, p<0.001). In multivariable logistic regression analysis and corresponding sensitivity analysis (bootstrap/subsample inclusion frequencies and lasso regression) including study arm, BMI, menopausal, cT, and cN status, histological grade, HER2-status, Ki67, ER, PR as continuous variables, only study arm and HER2 3+ status were significantly associated with pCR. Neoadjuvant treatment was well tolerated in both study arms and completed per protocol in 93/92 (ET+P+T/Pac+P+T) patients. Only 9/13 SAEs (ET+P+T/Pac+P+T) were reported during neoadjuvant therapy. PAM50 and QoL analysis are ongoing. Conclusions: WSG TP-II is the first randomized prospective trial comparing two neoadjuvant de-escalation treatments in HR+/HER2+ EBC. The excellent pCR rate of 57% after only 12 weeks of Pac+P+T was clearly superior to the still promising 24% pCR rate in pts treated by ET+P+T. In both arms, treatment efficacy was most pronounced in HER2 3+ tumors. Survival results need to be awaited before definite recommendations for a de-escalated regimen in HR+/HER2+ EBC can be made. Clinical trial information: 2016-005157-21 .

Efficacy of deescalated chemotherapy according to PAM50 subtypes, immune and proliferation genes in triple-negative early breast cancer: Primary translational analysis of the WSG-ADAPT-TN trial

In the neoadjuvant WSG-ADAPT-TN trial, 12-week nab-paclitaxel + carboplatin (nab-pac/carbo) was highly effective and superior to nab-paclitaxel + gemcitabine (nab-pac/gem) in triple-negative breast cancer regarding pathological complete response (pCR). Predictive markers for deescalated taxane/carbo use in TNBC need to be identified. Patients received 4 × nab-pac 125 mg/m² (plus carbo AUC2 or gem 1,000 mg/m² d1,8 q21). Expression of 119 genes and PAM50 scores by nCounter were available in 306/336 pretherapeutic samples. Interim survival analysis was planned after 36 months median follow-up. Basal-like (83.3%) compared to other subtypes was positively associated with pCR (38% vs. 20%, p = 0.015), as was lower HER2 score (p < 0.001). Proliferation biomarkers were positively associated with pCR, that is, PAM50 proliferation, ROR scores (all p < 0.004), higher Ki-67 (IHC; p < 0.001). For nab-pac/carbo, expression of immunological (CD8, PD1 and PFDL1) genes and proliferation markers (proliferation and ROR scores, MKI67, CDC20, NUF2, KIF2C, CENPF, EMP3 and TYMS) were positively associated with pCR (p < 0.05 for all). For nab-pac/gem, angiogenesis genes were negatively associated with pCR (ANGPTL4: p = 0.05; FGFR4: p = 0.02; VEGFA: p = 0.03). pCR after 12 weeks was strongly associated with favorable outcome (3y event-free survival: 92% vs. 71%, p < 0.001). In early TNBC, basal-like subtype, higher Ki-67 (IHC) and lower HER2 score were, associated with chemosensitivity. Chemoresistance pathways differed between the two taxane based combinations. Combination of proliferation/immune markers and PAM50 subtype could allow patient selection for further deescalated chemotherapy and/or immune treatment approaches.

ADAPTcycle: Adjuvant dynamic marker-adjusted personalized therapy comparing endocrine therapy plus ribociclib versus chemotherapy in intermediate-risk HR+/HER2- early breast cancer

TPS596

Background: WSG (West German Study Group)-ADAPTcycle is a prospective, multi-center, interventional, two-arm, open-label, controlled (neo)adjuvant, non-blinded, randomized phase III trial (EudraCT 2018-003749-40). It investigates whether HR+/HER2- intermediate-risk patients (pts) (about 20 % of HR+/HER2- early breast cancer, EBC) identified during screening (OncotypeDX and 3-week endocrine therapy (ET)) derive additional benefit from 2-years of the CDK4/6 inhibitor ribociclib plus ET compared to chemotherapy (CT) (followed by adjuvant ET). Co-primary endpoints are disease-free and distant disease-free survival. Methods: Starting Q1 2019 (enrollment 36 months, 80 sites), 5600 pts will be screened and 1670 randomized in a 3:2 ratio (1002 to ribociclib + ET; 668 to standard CT followed by ET). Pre-/postmenopausal pts with histologically confirmed invasive HR+/HER2- EBC at clinically enhanced risk (cT2-4 or Ki67 > 20 % or G3 or cN+) are eligible if they fulfill the ADAPT intermediate-risk group criteria: Recurrence Score (RS) ≤ 25 and poor endocrine response or RS > 25 and good endocrine response in p/cN0-1 pts or RS ≤ 25 with good endocrine response in c/pN2-3 pts. Endocrine responsiveness is determined by Ki67 response (drop to ≤ 10 %) after 3-week ET. Treatment duration is 2 years for the ribociclib + ET (premenopausal: AI + GnRH) arm and 16-24 weeks for the CT arm; treatment can be given in the neoadjuvant or adjuvant setting. 5-year follow-up consists of standard adjuvant ET. Patient reported outcomes (ePROs) are collected using CANKADO; ECG monitoring is performed using a novel CANKADO-based methodology. For translational analyses, tumor tissue will be collected at baseline (prior to ET), after 3-weeks ET (+/- 1w). Additional samples are required if residual tumor is diagnosed in case of neoadjuvant treatment and at time of recurrence. Exploratory tissue biomarker research will be conducted to assess alterations of molecular markers (e. g., ESR1, PIK3CA, CCND1, CDKN2A, RB1). Circulating DNA and tumor cells from blood samples will be used to assess mutations, gene expression, etc. Clinical trial information: 2018-003749-40.

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&lt;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&lt;.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 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&lt;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 &gt;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.

De-Escalation Strategies in Human Epidermal Growth Factor Receptor 2 (HER2)–Positive Early Breast Cancer (BC): Final Analysis of the West German Study Group Adjuvant Dynamic Marker-Adjusted Personalized Therapy Trial Optimizing Risk Assessment and Therapy Response Prediction in Early BC HER2- and Hormone Receptor–Positive Phase II Randomized Trial—Efficacy, Safety, and Predictive Markers for 12 Weeks of Neoadjuvant Trastuzumab Emtansine With or Without Endocrine Therapy (ET) Versus Trastuzumab Plus ET

Purpose

Human epidermal growth factor receptor 2 (HER2)–positive/hormone receptor (HR)–positive breast cancer is a distinct subgroup associated with lower chemotherapy sensitivity and slightly better outcome than HER2-positive/HR-negative disease. Little is known about the efficacy of the combination of endocrine therapy (ET) with trastuzumab or with the potent antibody-cytotoxic, anti-HER2 compound trastuzumab emtansine (T-DM1) with or without ET for this subgroup. The West German Study Group trial, ADAPT (Adjuvant Dynamic Marker-Adjusted Personalized Therapy Trial Optimizing Risk Assessment and Therapy Response Prediction in Early Breast Cancer) compares pathologic complete response (pCR) rates of T-DM1 versus trastuzumab with ET in early HER2-positive/HR-positive breast cancer.

Patients and Methods

In this prospective, neoadjuvant, phase II trial, 375 patients with early breast cancer with HER2-positive and HR-positive status (n = 463 screened) were randomly assigned to 12 weeks of T-DM1 with or without ET or to trastuzumab with ET. The primary end point was pCR (ypT0/is/ypN0). Early response was assessed in 3-week post-therapeutic core biopsies (proliferation decrease ≥ 30% Ki-67 or cellularity response). Secondary end points included safety and predictive impact of early response on pCR. Adjuvant therapy followed national standards.

Results

Baseline characteristics were well balanced among the arms. More than 90% of patients completed the therapy per protocol. pCR was observed in 41.0% of patients treated with T-DM1, 41.5% of patients treated with T-DM1 and ET, and 15.1% with trastuzumab and ET ( P < .001). Early responders (67% of patients with assessable response) achieved pCR in 35.7% compared with 19.8% in nonresponders (odds ratio, 2.2; 95% CI, 1.24 to 4.19). T-DM1 was associated with a significantly higher prevalence of grade 1 to 2 toxicities, especially thrombocytopenia, nausea, and elevation of liver enzymes. Overall toxicity was low; seventeen therapy-related severe adverse events (T-DM1 arms v trastuzumab plus ET; 5.3% v 3.1%, respectively) were reported.

Conclusion

The ADAPT HER2-positive/HR-positive trial demonstrates that neoadjuvant T-DM1 (with or without ET) given for only 12 weeks results in a clinically meaningful pCR rate. Thus, a substantial number of patients are spared the adverse effects of systemic chemotherapy.

Prospective WSG phase III PlanB trial: Final analysis of adjuvant 4xEC→4x doc vs. 6x docetaxel/cyclophosphamide in patients with high clinical risk and intermediate-to-high genomic risk HER2-negative, early breast cancer

504

Background: Optimal chemotherapy in HER2-negative, particularly HR-positive, early breast cancer (EBC), especially the survival impact of anthracyclines, is still a matter of debate. Retrospective analyses saw most benefit of 6xCEF vs. 6xCMF in HER2+ EBC. Prospective trials have shown conflicting results; no predictive molecular factors have been validated so far, particularly for HR+ EBC. The WSG PlanB trial is the first trial that randomized only patients with high clinical risk or with Recurrence Score >11 in the HR+/HER2- subgroup (pN0-1). Patients with RS<11 (pN0-1) had an excellent prognosis (five-year DFS of 94%) with endocrine therapy alone (Gluz et al. ASCO 2016). Methods: The WSG PlanB trial was originally planned as a non-inferiority study for comparison of 6 cycles of anthracycline-free TC (Arm A) vs. standard anthracycline-taxane based chemotherapy (4xEC→4xDoc) (Arm B) in patients with high-risk pN0 (T2-4, G2-3, <35 years, or high uPA/PAI-1) or pN+ HER2- EBC. Following an early amendment, Oncotype DX was performed in all HR+ tumors, and omission of chemotherapy (CT) was recommended in RS≤11 HR+ pN0-1 disease. Primary endpoint was DFS, defined as time to any recurrence, secondary cancer or death. Final analysis for the CT randomization was planned after completed 5-year follow-up in all patients. Results: From 2009 to 2011, PlanB enrolled 3198 patients (n=3073 with central pathology review). In 348 patients (15.3%), CT was omitted based on RS≤11. 2449 patients were randomized to 6xTC (n=1222) and 4xEC→4xDoc (n=1227). Within this cohort, 41% were pN+, 42% had G3 tumors and 18% HR-negative tumors by central pathology. After median follow-up of 61 months, very similar five-year DFS of 89.9% [88.1%-91.7%] vs. 90.2% [88.4%-92.0%] and five-year OS of 94.7% [93.4%-96.1%] vs. 94.6% [93.2%-96.0%] were observed in Arms A vs. B. Five treatment-related deaths were observed in Arm A (TC) vs. one in Arm B (EC-Doc) (0.4% vs. 0.1%), despite a trend to more SAE’s in Arm B vs. Arm A (n=397 vs. 358). Although recurrence score is a strong prognostic factor, it was not predictive for anthracycline efficacy; no efficacy differences between the study arms were observed in (locally) triple-negative patients or in those with >4 involved lymph nodes, despite the prognostic impact of these factors. Conclusion: In the WSG PlanB trial, patients with early HER2-negative BC seem to be sufficiently treated by six cycles of docetaxel/cyclophosphamide compared to four cycles of EC followed by four cycles of docetaxel -- no efficacy differences are evident in high-risk subgroups defined by triple-negative status, nodal status, or high Recurrence Score. Further prospective studies are urgently needed before final conclusions for impact of anthracyclines in HER2-negative BC can be drawn. Clinical trial information: NCT01049425.

Association of molecular subtype, proliferation, and immune genes with efficacy of carboplatin versus gemcitabine addition to taxane-based, anthracycline-free neoadjuvant chemotherapy in early triple-negative breast cancer (TNBC): Results of the randomized WSG ADAPT-TN trial

573

Background: In the ADAPT-TN neoadjuvant trial, 12-week nab-paclitaxel (nab- pac)+carboplatin (carbo) was highly effective and superior to nab-pac+gemcitabine (gem). However, within TNBC, reliable predictive markers for carbo use have yet to be identified. Methods: Patients with early TNBC (centrally confirmed) were treated by nab-pac 125 mg/m2 with either carbo AUC2 or gem 1000 mg/m2 d 1,8 q21 given for 4 cycles. Genomic data (80 genes) and Prosigna (PAM-50) scores were available in 306 pre-therapeutic samples of 331 treated patients. Fisher’s exact test was performed for pCR differences; associations of continuous measurements or scores with pCR were analyzed by the Mann-Whitney statistic. Results: pCR was 44.5% to 28.4% (p=.004) in favor of nab-pac - carbo. Specifically within the carbo- containing arm, immunological (CD8, PD1, PFDL1) genes and proliferation markers (proliferation score and ROR scores, MKI67, CDC20, NUF2, KIF2C, CENPF, EMP3, TYMS) were positively associated with pCR (p<.05 for all). Specifically within the gem-arm, angiogenesis genes were negatively associated with pCR (ANGPTL4: p=.05; FGFR4: p=.02; VEGFA: p=.03). In the whole collective, basal-like (83.3%) was favorable for pCR (38% vs. 20%, p=.015) compared to other subtypes (HER: 6.4%; luminal-A: 1.7%; normal: 8.7%), as was lower HER-2 score (p<.001). Proliferation was positively associated with pCR: i.e., Pam50 proliferation score, ROR scores (all p<.004), and higher Ki67 by central IHC (p<.001) -- though not MKI67 RNA expression, despite their moderate correlation. Conclusions: In early TNBC, basal-like subtype, higher Ki67 (by IHC), and lower HER-2 score were associated with chemo-sensitivity for both neoadjuvant arms. Chemo-resistance pathways differed between the two taxane-based combinations (low proliferation and immune marker gene expression for carbo, high angiogenesis for gem). The positive predictive impact of immunological genes in the nab-pac - carbo arm could influence optimal patient selection for immune-modulative therapy. Clinical trial information: NCT01815242.

Results of multicenter phase II WSG Neo-Predict trial: Predictive markers for evaluation of response to neoadjuvant paclitaxel+trastuzumab+lapatinib in HER2-positive early breast cancer

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Background: Trastuzumab (T) and Lapatinib (L) containing neoadjuvant chemotherapy (NACT) increases pathological complete response (pCR) (vs. T or nihil) in HER2+ early breast cancer (EBC). Early clinical response markers (e.g. Ki67) in a 3-week biopsy or in residual tumor correlate with therapy efficacy and risk of relapse. This WSG Neo-Predict trial aimed to define early predictive markers for therapy response in a dual blockade (T+L) NACT setting. Methods: Patients with cT1c-cT4c HER2+ EBC were treated by paclitaxel (P) (80 mg/m2weekly) with L (750 mg p.o. daily) + T (2 mg/kg) weekly for 12 weeks. Adjuvant treatment with 4 cycles of Epirubicin/Cyclophosphamide (omission allowed in patients with pCR) and T for an additional 40 weeks was recommended. Primary objectives were pCR (ypT0/is/ypN0) and identification of a dynamic predictive test for pCR using a re-biopsy after three weeks of NACT (early response defined as central Ki67 decrease >30% (vs. baseline) and/or low cellularity (<500 invasive tumor cells)). Results: From 2013-2015, 64 patients (n=80 planned) were recruited. Overall pCR was 41% (41% for HER2+/HR+ (n=34) and 45.5% for HER2+//HR- (n=22)). A 0% pCR in the “non-responder” (n=7) group (vs. 50% in the “responder” (n=34) and 42% in the “missing response” (n=20) groups) is intriguing despite methodological limitations. Missing data for early response assessment in a substantial number of patients and negative DFS data from the ALTTO trial did not justify trial continuation. 27% of patients experienced severe adverse events (AE). 11.5% had > grade 3 AEs (including diarrhea, septic shock, leukopenia, and pneumonia). Conclusions: We observed a clinically meaningful pCR with moderate toxicity with only 12 weeks of paclitaxel weekly with dual HER2 blockade (T+L). Effect of additional chemotherapy in patients with pCR after 12 weeks of monochemotherapy remains questionable due to a strong prognostic effect of pCR in HER2+ EBC. In view of 0% pCR (by hypothesis-generating explorative analysis), a different treatment approach should be investigated in patients without “early response” by further prospective trials. Clinical trial information: 2012-003679-21.

Abstract P1-09-05: The role of immune and apoptosis markers for prediction of pCR in the WSG-ADAPT HER2+/HR+ phase II trial evaluating 12-weeks of neoadjuvant TDM1 ± endocrine therapy (ET) versus T + ET in HER2-positive hormone-receptor-positive early breast cancer (EBC)

Background: Immune and apoptosis biomarkers are potential prognostic/predictive markers in HER2+ EBC. High PD-L1 expression was shown to be predictive for lower pCR after chemotherapy+trastuzumab+/-pertuzumab, particularly in HER2+, ER- disease. Yet, HER2+ EBC co-expressing hormone receptors is a distinct entity.

The ADAPT HER2+/HR+ phase II trial (n=376) compared 12 weeks of neoadjuvant T-DM1 + ET vs. trastuzumab (T)+ET and demonstrated pCR rates of about 41% in both (well tolerated) T-DM1 arms.

Methods: In order to identify potential early predictors for pCR (i.e. no invasive tumor in breast and lymph nodes), immune markers (PDL1 on infiltrating immune cells (IIC) and on tumor cells (TC); CD8 in invasive margin and in tumor center) and apoptosis markers (bcl-2; mcl-2) were determined by immunohistochemistry (IHC; H-scores) in core biopsy sections obtained at primary diagnosis and at cycle 2. For multivariate logistic regression, each biomarker (separately), clinical factors (Ki-67, cT, cN) and therapy were entered. All analyses were exploratory.

Results:Biomarkers were available in up to 326 patients (pts) at baseline and up to 170 pts at 3 weeks (due to low tumor content in 2nd core biopsy).

Baseline IIC-PDL1 was associated with pCR in the T-DM1 arm (OR 2.89; 95%CI: 1.11-7.51); IIC-PDL1 at cycle 2 was not associated with pCR.

PD-L1 expression in TC was rare (2%); cycle-2 TC-PD-L1 was associated with pCR in all pts and in the pooled TDM-1 arms.

High baseline CD8 in tumor center was associated with pCR in the whole cohort (OR 2.4; CI: 1.04 – 5.5) and in the T+ET arm (OR=10.1; CI: 1.12 - 91.6) and at cycle 2 in all pts (OR=9.52; CI: 2.17 – 41), in pooled TDM-1 arms (OR=15.7; CI: 2.49 – 99), and in TDM-1+ET (OR=25.05; CI: 2.12 – 295). Increases in this marker also predicted pCR in all pts, pooled TDM-1, and in TDM-1+ET. Association of cycle-2 CD8 in tumor center with pCR persisted in multivariate models.

Lower baseline CD8 in invasive margin was associated with pCR in the T-DM1 arm (OR=0.09; CI: 0.01-0.69), but at cycle 2 in all pts (OR=18.1; CI: 1.60 – 204) and in pooled TDM-1 arms (OR=23.5; CI: 1.1 - 500). This positive impact persisted in multivariate models.

Bcl-2 expression at baseline was associated with non-pCR in all pts (OR=0.28, CI: 0.12 - 0.66), in the pooled T-DM1 arms (OR=0.216, CI: 0.08 - 0.61), and particularly in the T-DM1+ET arm (OR=0.14; CI: 0.03 - 0.71). This association persisted in multivariate analysis. At cycle 2, lower bcl-2 had OR=0.16 (CI: 0.03 - 0.96) in the pooled T-DM1 arms. No association with efficacy was seen for mcl-1.

Conclusions: The WSG-ADAPT HER2+/HR+ phase II trial is the first international trial to focus on HER2+/HR+ EBC alone and the first to show substantial pCR rates of &gt; 40% after only 12 weeks of T-DM1 -- without standard chemotherapy.

Expression of bcl-2 may affect resistance to T-DM1. High immune activity at baseline and/or cycle 2 seems to be associated with pCR. The association of CD8 expression and its changes with therapy efficacy is complex and could depend on ET.

Further biomarker analyses are ongoing and will be presented at the meeting.

Citation Format: Harbeck N, Nitz UA, Matthias C, Kates R, Braun M, Kümmel S, Schumacher C, Potenberg J, Kraemer S, Kleine-Tebbe A, Augustin D, Aktas B, Forstbauer H, Tio J, Liedtke C, Grischke E-M, de Haas SL, Deurloo R, Schumacher J, Wuerstlein R, Kreipe HH, Gluz O. The role of immune and apoptosis markers for prediction of pCR in the WSG-ADAPT HER2+/HR+ phase II trial evaluating 12-weeks of neoadjuvant TDM1 ± endocrine therapy (ET) versus T + ET in HER2-positive hormone-receptor-positive early breast cancer (EBC) [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 P1-09-05.

HER2 testing in gastric cancer diagnosis: Insights on variables influencing HER2-positivity from a large, multicenter, observational study in Germany

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Background: HER2 testing is routine for metastatic gastric or gastroesophageal junction cancer (mGC/GEJC). Differing HER2-positivity rates are considered to be potential indicators of inter- and intra-laboratory deviations in testing quality. The influence of patient-, sample-, or method-related factors on HER2-positivity has not been assessed systematically. Methods: This observational, prospective study collected routine HER2 test result, patient- and tumor-related factors, sample source, and testing method data to identify factors influencing HER2-positivity rates in mGC/GEJC. Influencing factors were identified using stepwise multiple logistic regression and a statistical model was developed to predict probability of HER2-positivity. Institutes with deviations in HER2-positivity rates were identified by comparing 95% confidence intervals (CI) of documented and predicted rates. Results: From Jan 2013 to Dec 2015, data were collected from 2761 mGC/mGEJC routine diagnostic specimens at 50 pathology institutes in Germany. Final analyses included 2033 specimens with HER2 test results (1554 mGC and 479 mGEJC cases). Overall HER2-positivity rates across centers was 19.8% for mGC and 30.5% for mGEJC. Lauren classification showed the highest correlation with HER2-positivity, followed by HER2 testing rate, tumor location, type of sample (resection vs biopsy), and testing method (immunohistochemistry vs fluorescence in situ hybridization) (all P < .05). Four institutes were identified with predicted HER2-positivity rates outside the 95% CI of the documented rate. Conclusions: This is the first study to report on multifactorial parameters that impact HER2-positivity rates in routine mGC/GEJC diagnostics. Results suggest that effective assessment of HER2 testing quality based on positivity rates should consider tumor characteristics, testing rate, type of specimen, and testing method, as they affect HER2-positivity. As therapy options for HER2-positive mGC/GEJC continue to evolve, reliably identifying the right patients is key.

[HER2 testing in gastric cancer - results of a German expert meeting]

Valid HER2 testing is essential for optimal therapy of patients with HER2 positive gastric cancer and the correct use of first-line treatment. While each breast cancer is routinely being tested for the HER2 status, HER2 testing in gastric cancer has still not become part of the routine and is often only done upon request by the therapist. An interdisciplinary German expert group took the challenges of HER2 testing in gastric cancer as an opportunity to address essential aspects and questions for the practical use of HER2 testing in this indication from the perspective of pathologists and therapists. The recommendations made in this manuscript reflect the consensus of all participants and correspond to their opinions and long-term experience.

[Necrotizing funisitis : Histopathological indicator of occult congenital syphilis]

Congenital syphilis is a rare disease in central Europe. Placental changes may be non-specific but a typical finding is necrotizing funisitis of the umbilical cord. In a case report we describe how the histopathological incidental finding of B lymphocyte-rich, necrotizing funisitis led to the diagnosis of a previously unknown Treponema pallidum infection in parents and their newborn child. The pathological suspicion of congenital syphilis, although rare, has implications for the clinical management (serological evaluation of parents and child as well as the social environment, evaluation of viral coinfection and treatment decision) and is a notifiable disease.

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.

[Cytopathology in the diagnostics of hematological diseases]

Whereas in many fields of surgical pathology examination of cytological smears and analysis of histological tissue sections provide alternative methods which are chosen according to the clinical requirements, in hematopathology both types of morphological investigation are routinely applied in parallel and simultaneously. This procedure improves the diagnostic precision and safety. Unlike other European countries in Germany both procedures are performed by different specialties. Cytology is the responsibility of hematologists whereas histology is carried out by pathologists, which interferes with an integrative diagnostic approach unless intense communication takes place. Ideally, in the diagnosis of hematological disorders histology of bone marrow trephines should be studied in conjunction with smears of peripheral blood and bone marrow. In many instances, further complementary investigations, such as flow cytometry, cytogenetics and increasingly molecular pathological studies are necessary to guarantee an adequate modern state of diagnostics in hematopathology.

Comprehensive Molecular Profiling of Archival Bone Marrow Trephines Using a Commercially Available Leukemia Panel and Semiconductor-Based Targeted Resequencing

Comprehensive mutation profiling becomes more and more important in hematopathology complementing morphological and immunohistochemical evaluation of fixed, decalcified and embedded bone marrow biopsies for diagnostic, prognostic and also predictive purposes. However, the number and the size of relevant genes leave conventional Sanger sequencing impracticable in terms of costs, required input DNA, and turnaround time. Since most published protocols and commercially available reagents for targeted resequencing of gene panels are established and validated for the analysis of fresh bone marrow aspirate or peripheral blood it remains to be proven whether the available technology can be transferred to the analysis of archival trephines. Therefore, the performance of the recently available Ion AmpliSeq AML Research panel (LifeTechnologies) was evaluated for the analysis of fragmented DNA extracted from archival bone marrow trephines. Taking fresh aspirate as gold standard all clinically relevant mutations (n = 17) as well as 25 well-annotated SNPs could be identified reliably with high quality in the corresponding archival trephines of the training set (n = 10). Pre-treatment of the extracted DNA with Uracil-DNA-Glycosylase reduced the number of low level artificial sequence variants by more than 60%, vastly reducing time required for proper evaluation of the sequencing results. Subsequently, randomly picked FFPE samples (n = 41) were analyzed to evaluate sequencing performance under routine conditions. Thereby all known mutations (n = 43) could be verified and 36 additional mutations in genes not yet covered by the routine work-up (e.g., TET2, ASXL1, DNMT3A), demonstrating the feasibility of this approach and the gain of diagnostically relevant information. The dramatically reduced amount of input DNA, the increase in sensitivity as well as calculated cost-effectiveness, low hands on , and turn-around-time, necessary for the analysis of 237 amplicons strongly argue for replacing Sanger sequencing by this semiconductor-based targeted resequencing approach.

Predictive role of HER2/neu, topoisomerase-II-alpha, and tissue inhibitor of metalloproteinases (TIMP-1) for response to adjuvant taxane-based chemotherapy in patients with intermediate-risk breast cancer: results from the WSG-AGO EC-Doc trial

Taxane-anthracycline-based adjuvant chemotherapy is standard of care in patients with node-positive breast cancer (BC) but is also associated with severe side effects and significant costs. It is yet unclear, which biomarkers would predict benefit from taxanes and/or general chemoresistance. In this study, we investigate a large cohort of patients with intermediate-risk BC treated within the WSG EC-DOC Trial for the predictive impact of topoisomerase-II-alpha, HER2/neu, and TIMP-1. Tumor tissue was available in a representative cohort of 772 cases of the WSG EC-DOC Trial collective which compared 4xEC-4xDoc versus 6xCEF/CMF. In addition to hormone receptor status and Ki-67, HER2/neu+ and topoisomerase-II-alpha status using fluorescence in situ hybridisation (FISH) and immunohistochemistry, TIMP-1 using immunohistochemistry, and aneuploidy of chromosome 17 using FISH were evaluated and correlated with outcome and taxane benefit. There was significant superiority of EC-Doc over CEF regarding 5-year DFS (90 vs. 80 %, respectively, p = 0.006) particularly in patient subgroups defined by HR+, HER2/neu+, high proliferation (i.e., Ki-67 ≥ 20 %), patient age >50 years old and normal chromosome 17 status, high TIMP-1 and low topoisomerase-II-alpha protein expression. Significant prognostic factors in multivariate analysis were EC-Doc therapy (HR = 0.61; 95 %CI 0.38-0.986), age <50 years old (HR = 1.682; 95 %CI 1.025-2.579), centrally assessed grade 3 (HR = 4.657; 95 %CI 1.809-11.989), and high Ki-67 (HR = 2.232; 95 %CI 1.209-4.121). Interestingly, we observed a significant interaction between treatment arm (EC-Doc vs. CEF) and high topoisomerase-II-alpha protein expression (HR = 0.427; 95 %CI 0.203-0.900) in multivariate interaction analysis. Despite of univariate predictive effect of HER2/neu status among other factors only topoisomerase-II-alpha protein expression was associated with significant benefit from EC-Doc compared to CEF by multivariate interaction analysis.