De-escalated neoadjuvant pertuzumab plus trastuzumab therapy with or without weekly paclitaxel in HER2-positive, hormone receptor-negative, early breast cancer (WSG-ADAPT-HER2+/HR-): survival outcomes from a multicentre, open-label, randomised, phase 2 trial.

BACKGROUND: Several de-escalation neoadjuvant strategies have been investigated to reduce the use of chemotherapy in HER2-positive early breast cancer using pathological complete response as a surrogate endpoint; there are few survival data from these trials. Here, we report 5-year survival data in the WSG-ADAPT-HER2+/HR- trial and address the effect of pathological complete response, early therapy response, and molecular subtype. METHODS: WSG-ASAPT-HER2+/HR-, a part of the ADAPT umbrella trial performed in patients with different subtypes of early breast cancer, was an investigator-initiated, multicentre, open-label, randomised, phase 2 trial done at 40 Breast Cancer Centres in Germany. Eligible patients were aged 18 years or older with histologically confirmed, unilateral, primary invasive, non-inflammatory early breast cancer, hormone receptor-negative and HER2-positive status, and an Eastern Cooperative Oncology Group performance status of 0 or 1 or a Karnofsky performance status of at least 80%. Patients were randomly assigned (5:2, block size 21, stratified by centre and clinical nodal status) to 12 weeks of either trastuzumab (8 mg/kg loading dose, then 6 mg/kg every 3 weeks) plus pertuzumab (840 mg loading dose, then 420 mg every 3 weeks) or trastuzumab plus pertuzumab plus paclitaxel (80 mg/m2 weekly); all drugs were administered intravenously. The primary objective of the trial was to compare the number of patients with a pathological complete response at surgery (ie, no invasive tumour cells in breast and lymph nodes [ypT0/is ypN0], the primary endpoint) in early responders (ie, low cellularity or Ki67 decrease ≥30% after 3 weeks) in the trastuzumab plus pertuzumab group versus all patients (irrespective of an early response) in the trastuzumab plus pertuzumab plus paclitaxel group. Non-inferiority was defined as a pathological complete response no worse than 23% lower in the early-responder proportion of patients in the trastuzumab plus pertuzumab group than in the entire trastuzumab plus pertuzumab plus paclitaxel group. The primary endpoint has been reported previously. Additionally, the primary objective of the ADAPT umbrella trial was the evaluation of the effect of pathological complete response on invasive disease-free survival. At investigator's discretion, further chemotherapy could be omitted in patients with a pathological complete response. Secondary survival endpoints were 5-year invasive disease-free survival, relapse-free survival, locoregional relapse-free survival, distant disease-free survival, and overall survival. The effect of pathological complete response on survival was estimated by Cox regression analysis. All analyses are reported in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT01817452, and is closed to recruitment. FINDINGS: Between March 3, 2014, and Oct 6, 2015, 134 patients were recruited and randomly assigned to treatment, 92 to trastuzumab plus pertuzumab and 42 to trastuzumab plus pertuzumab plus paclitaxel. Median follow-up in survivors was 59·9 months (IQR 53·4-61·4). There were no significant differences between the treatment groups in invasive disease-free survival, relapse-free survival, locoregional relapse-free survival, distant disease-free survival, and overall survival. In the trastuzumab plus pertuzumab plus paclitaxel group and in the trastuzumab plus pertuzumab group, the proportions of patients achieving 5-year survival respectively were 98% (95% CI 84-100) and 87% (78-93) for invasive disease-free survival (hazard ratio [HR] 0·32, 95% CI 0·07-1·49; p=0·15); 98% (95% CI 84-100) and 89% (79-94) for relapse-free survival (HR 0·41, 95% CI 0·09-1·91; p=0·25); 100% (95% CI not estimable) and 95% (88-98) for locoregional relapse-free survival (HR 0·41, 95% CI 0·05-3·75; p=0·43); 98% (95% CI 84-100) and 92% (83-96) for distant disease-free survival (HR 0·35, 95% CI 0·04-3·12; p=0·36), and 98% (95% CI 84-100) and 94% (86-97) for overall survival (HR 0·41, 95% CI 0·05-3·63; p=0·43). Pathological complete response was associated with improved invasive disease-free survival (HR 0·14, 95% CI 0·03-0·64; p=0·011). Two invasive disease-free survival events occurred after a pathological complete response (one in each treatment group). INTERPRETATION: The WSG-ADAPT-HER2+/HR- trial showed good survival rates in patients with a pathological complete response after de-escalated 12-week trastuzumab plus pertuzumab with or without weekly paclitaxel. Omission of further chemotherapy did not affect invasive disease-free survival in patients with a pathological complete response. 12 weeks of weekly paclitaxel plus dual HER2 blockade could be an efficacious de-escalated neoadjuvant regimen in patients with hormone receptor-negative, HER2-positive early breast cancer with high pathological complete response rates and good 5-year outcomes. Further trials of this approach are ongoing. FUNDING: Roche, Bayer. TRANSLATION: For the German translation of the abstract see Supplementary Materials section.

A Prospective, Multicenter Registry Study to Evaluate the Clinical Feasibility of Targeted Axillary Dissection (TAD) in Node-positive Breast Cancer Patients.

OBJECTIVE: This study aimed to investigate the feasibility and accuracy of non-radioactive TLN biopsy and TAD in routine clinical practice. BACKGROUND DATA: TAD involves TLN biopsy (TLNB) and sentinel lymph node biopsy and was recently introduced as a new standard for less invasive axillary staging in BC patients undergoing neoadjuvant systemic therapy (NST); however, clinical evidence is limited. METHODS: The SenTa study is a prospective registry study conducted at 50 centers. Patients with invasive BC who nderwent clip insertion into the most suspicious axillary lymph node were eligible. Axillary surgery was performed with or without sentinel lymph node biopsy, TLNB, and/or axillary lymph node dissection (ALND). Main endpoints were the detection rate and FNR of TLNB and TAD after NST. RESULTS: Between 2017 and 2018, 548 consecutive BC patients underwent clip placement into biopsy-confirmed positive lymph nodes. After NST (n = 473), the clipped TLN was intraoperatively resected in 329 of 423 patients [77.8%, 95% confidence interval (CI): 74.0-82.0]. TAD was successful in 199 of 229 patients (detection rate: 86.9%, 95% CI: 81.8-91.0), the SLN and TLN were identical in 129 patient (64.8%). FNRs were 7.2% (8 of 111, 95% CI: 3.1-13.6) for TLNB followed by ALND (n = 203) and 4.3% (2 of 46, 95% CI: 0.5-14.8) for TAD followed by ALND (n = 77). CONCLUSIONS: The SenTa study demonstrates the feasibility of TAD in a real-world cohort of BC patients. Our findings are of great importance for de-escalation of surgical strategies.

Magnetic resonance imaging and ultrasound for prediction of residual tumor size in early breast cancer within the ADAPT subtrials.

BACKGROUND: Prediction of histological tumor size by post-neoadjuvant therapy (NAT) ultrasound and magnetic resonance imaging (MRI) was evaluated in different breast cancer subtypes. METHODS: Imaging was performed after 12-week NAT in patients enrolled into three neoadjuvant WSG ADAPT subtrials. Imaging performance was analyzed for prediction of residual tumor measuring ≤10 mm and summarized using positive (PPV) and negative (NPV) predictive values. RESULTS: A total of 248 and 588 patients had MRI and ultrasound, respectively. Tumor size was over- or underestimated by < 10 mm in 4.4% and 21.8% of patients by MRI and in 10.2% and 15.8% by ultrasound. Overall, NPV (proportion of correctly predicted tumor size ≤10 mm) of MRI and ultrasound was 0.92 and 0.83; PPV (correctly predicted tumor size > 10 mm) was 0.52 and 0.61. MRI demonstrated a higher NPV and lower PPV than ultrasound in hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-positive and in HR-/HER2+ tumors. Both methods had a comparable NPV and PPV in HR-/HER2- tumors. CONCLUSIONS: In HR+/HER2+ and HR-/HER2+ breast cancer, MRI is less likely than ultrasound to underestimate while ultrasound is associated with a lower risk to overestimate tumor size. These findings may help to select the most optimal imaging approach for planning surgery after NAT. TRIAL REGISTRATION: Clinicaltrials.gov , NCT01815242 (registered on March 21, 2013), NCT01817452 (registered on March 25, 2013), and NCT01779206 (registered on January 30, 2013).

Early response by MR imaging and ultrasound as predictor of pathologic complete response to 12-week neoadjuvant therapy for different early breast cancer subtypes: Combined analysis from the WSG ADAPT subtrials.

We evaluated the role of early response after 3 weeks of neoadjuvant treatment (NAT) assessed by ultrasound (US), magnetic resonance imaging (MRI) and Ki-67 dynamics for prediction of pathologic complete response (pCR) in different early breast cancer subtypes. Patients with HR+/HER2+, HR-/HER2- and HR-/HER2+ tumors enrolled into three neoadjuvant WSG ADAPT subtrials underwent US, MRI and Ki-67 assessment at diagnosis and after 3 weeks of NAT. Early response was defined as complete or partial response (US, MRI) and ≥30% proliferation decrease or <500 invasive tumor cells (Ki-67). Predictive values and area under the receiver operating characteristic (AUC) curves for prediction of pCR (ypT0/is ypN0) after 12-week NAT were calculated. Two hundred twenty-six had MRI and 401 US; 107 underwent both MRI and US. All three methods yielded a similar AUC in HR+/HER2+ (0.66-0.67) and HR-/HER2- tumors (0.53-0.63), while MRI and Ki-67 performed better than US in HR-/HER2+ tumors (0.83 and 0.79 vs 0.56). Adding MRI+/-Ki-67 increased AUC of US in HR-/HER2+ tumors to 0.64 to 0.75. MRI and Ki-67 demonstrated highest sensitivity in HR-/HER2- (0.8-1) and HR-/HER2+ tumors (1, both). Negative predictive value was similar for all methods in HR+/HER2+ (0.71-0.74) and HR-/HER2- tumors (0.85-1), while it was higher for MRI and Ki-67 compared to US in HR-/HER2+ subtype (1 vs 0.5). Early response assessed by US, MRI and Ki-67 is a strong predictor for pCR after 12-week NAT. Strength of pCR prediction varies according to tumor subtype. Adding MRI+/-Ki-67 to US did not improve pCR prediction in majority of our patients.

Sorafenib plus topotecan versus placebo plus topotecan for platinum-resistant ovarian cancer (TRIAS): a multicentre, randomised, double-blind, placebo-controlled, phase 2 trial.

BACKGROUND: Antiangiogenic therapy has known activity in ovarian cancer. The investigator-initiated randomised phase 2 TRIAS trial assessed the multi-kinase inhibitor sorafenib combined with topotecan and continued as maintenance therapy for platinum-resistant or platinum-refractory ovarian cancer. METHODS: We did a multicentre, double-blind, placebo-controlled, randomised, phase 2 trial at 20 sites in Germany. Patients (≥18 years) with platinum-resistant ovarian cancer previously treated with two or fewer chemotherapy lines for recurrent disease were stratified (first vs later relapse) in block sizes of four and randomly assigned (1:1) using a web-generated response system to topotecan (1·25 mg/m2 on days 1-5) plus either oral sorafenib 400 mg or placebo twice daily on days 6-15, repeated every 21 days for six cycles, followed by daily maintenance sorafenib or placebo for up to 1 year in patients without progression. Investigators and patients were masked to allocation of sorafenib or placebo; topotecan treatment was open label. The primary endpoint was investigator-assessed progression-free survival, analysed in all patients who received at least one dose of study drug. This completed trial is registered with ClinicalTrials.gov, number NCT01047891. FINDINGS: Between Jan 18, 2010, and Sept 19, 2013, 185 patients were enrolled, 174 of whom were randomly assigned: 85 to sorafenib and 89 to placebo. Two patients in the sorafenib group had serious adverse events before treatment and were excluded from analyses. 83 patients in the sorafenib group and 89 in the placebo group started treatment. Progression-free survival was significantly improved with sorafenib versus placebo (hazard ratio 0·60, 95% CI 0·43-0·83; p=0·0018). Median progression-free survival was 6·7 months (95% CI 5·8-7·6) with sorafenib versus 4·4 months (3·7-5·0) with placebo. The most common grade 3-4 adverse events were leucopenia (57 [69%] of 83 patients in the sorafenib group vs 47 [53%] of 89 in the placebo group), neutropenia (46 [55%] vs 48 [54%]), and thrombocytopenia (23 [28%] vs 20 [22%]). Serious adverse events occurred in 49 (59%) of 83 sorafenib-treated patients and 45 (51%) of 89 placebo-treated patients. Of these, events were fatal in four patients (5%) in the sorafenib group (dyspnoea and poor general condition, septic shock, ascites and dyspnoea, and sigma perforation) and seven (8%) in the placebo group (pulmonary embolism in two patients, disease progression in two patients, and one case each of sepsis with fever, pleural effusion, and tumour cachexia). Sorafenib was associated with increased incidences of grade 3 hand-foot skin reaction (three [13%] vs 0 patients) and grade 2 alopecia (24 [29%] vs 12 [13%]). INTERPRETATION: Sorafenib, when given orally in combination with topotecan and continued as maintenance therapy, showed a statistically and clinically significant improvement in progression-free survival in women with platinum-resistant ovarian cancer. These encouraging results support the crucial role of antiangiogenesis as the treatment backbone in combination with chemotherapy, making this approach attractive for further assessment with other targeted strategies. FUNDING: Bayer, Amgen, and GlaxoSmithKline.

A randomized phase 2 study comparing EC or CMF versus nab-paclitaxel plus capecitabine as adjuvant chemotherapy for nonfrail elderly patients with moderate to high-risk early breast cancer (ICE II-GBG 52).

BACKGROUND: Although greater than 40% of breast cancers occur in patients aged ≥65 years, these individuals are frequently undertreated. Taxane-based adjuvant chemotherapy is considered the treatment of choice but to the authors' knowledge has only limited evidence in elderly patients. METHODS: Patients aged ≥65 years with a Charlson comorbidity index ≤2 and pT1/2 pN0/1 disease and either human epidermal growth factor receptor 2 (HER2)-positive, hormone receptor-negative, grade 3 (according to Common Terminology Criteria for Adverse Events [version 3.0]), high uPA/PAI-1 or any stage pT3/4 pN2/3 breast cancer were randomized to receive 4 cycles of adjuvant epirubicin and cyclophosphamide (EC) (epirubicin at a dose of 90 mg/m(2) and cyclophosphamide at a dose of 600 mg/m(2) intravenously [iv] on day 1 every 3 22 days) or 6 cycles of cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) (cyclophosphamide at a dose of 500 mg/m(2), methotrexate at a dose of 40 mg/m(2), and 5-fluorouracil at a dose of 600 mg/m(2) iv on days 1 plus 8 every 29 days) versus 6 cycles of nab-paclitaxel and capecitabine (nPX) (nab-paclitaxel at a dose of 100 mg/m(2) iv on days 1, 8, and 15 every 21 days with 1 week of rest every 6 weeks plus capecitabine at a dose of 2000 mg/m(2) orally on days 1-14 every 21 days). Primary endpoints were treatment discontinuations and overall frequency of adverse events. RESULTS: Thirteen of 198 patients (6.6%) discontinued EC/CMF and 69 of 193 patients (35.8%) discontinued nPX (P<.001) with 1 and 5 deaths observed during treatment, respectively. Grade 3 to 5 adverse events were more frequent among patients treated with EC/CMF (90.9%) than among those treated with nPX (64.8%) (P<.001), with hematological toxicities being more frequent with EC/CMF (88.4% vs 22.3%; P<.001), but nonhematological toxicities (hand-foot syndrome, diarrhea, mucositis, fatigue, sensory neuropathy, thromboembolisms, and metabolic disorders) being more frequent with nPX (58.5% vs 18.7%; P<.001). None of the geriatric scores (Charlson comorbidity index, Vulnerable Elders Survey [VES-13], Instrumental Activities of Daily Living [IADL], and G8) independently predicted grade 3 to 5 toxic events or treatment discontinuations. No differences in survival between the treatment groups were observed after 22.8 months. CONCLUSIONS: Compared with EC/CMF, treatment with nPX led to more treatment discontinuations and nonhematological toxicities in elderly patients with moderate or high-risk breast cancer.

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.

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 Trastuzumab-Emtansine With or Without Endocrine Therapy Versus Trastuzumab With Endocrine Therapy in HR+/HER2+ Early Breast Cancer: 5-Year Survival in the WSG-ADAPT-TP Trial.

PURPOSE: Neoadjuvant chemotherapy is standard of care in human epidermal growth factor receptor 2-positive (HER2+) early breast cancer (EBC), irrespective of the hormone receptor status. Trastuzumab-emtansine (T-DM1), antibody-drug conjugate, is highly effective in HER2+ EBC; however, no survival data are available for de-escalated antibody-drug conjugate-based neoadjuvant therapy without conventional chemotherapy. PATIENTS AND METHODS: In the WSG-ADAPT-TP (ClinicalTrials.gov identifier: NCT01779206) phase II trial, 375 centrally reviewed patients with hormone receptor-positive (HR+)/HER2+ EBC (clinical stage I-III) were randomly assigned to 12 weeks of T-DM1 with or without endocrine therapy (ET) or trastuzumab + ET once every 3 weeks (ratio 1:1:1). Adjuvant chemotherapy (ACT) omission was allowed in patients with pathologic complete response (pCR). In this study, we report the secondary survival end points and biomarker analysis. Patients who received at least one dose of study treatment were analyzed. Survival was analyzed using the Kaplan-Meier method, two-sided log-rank statistics, and Cox regression models stratified for nodal and menopausal status. P values < .05 were considered statistically significant. RESULTS: T-DM1, T-DM1 + ET, and trastuzumab + ET induced similar 5-year invasive disease-free survival (iDFS; 88.9%, 85.3%, 84.6%; Plog-rank = .608) and overall survival rates (97.2%, 96.4%, 96.3%; Plog-rank = .534). Patients with pCR versus non-pCR had improved 5-year iDFS rates (92.7% v 82.7%; hazard ratio, 0.40 [95% CI, 0.18 to 0.85]). Among the 117 patients with pCR, 41 did not receive ACT; 5-year iDFS rates were similar in those with (93.0% [95% CI, 84.0 to 97.0]) and without ACT (92.1% [95% CI, 77.5 to 97.4]; Plog-rank = .848). Translational research revealed that tumors with PIK3CA wild type, high immune marker expression, and luminal-A tumors (by PAM50) had an excellent prognosis with de-escalated anti-HER2 therapy. CONCLUSION: The WSG-ADAPT-TP trial demonstrated that pCR after 12 weeks of chemotherapy-free de-escalated neoadjuvant therapy was associated with excellent survival in HR+/HER2+ EBC without further ACT. Despite higher pCR rates for T-DM1 ± ET versus trastuzumab + ET, all trial arms had similar outcomes because of mandatory standard chemotherapy after non-pCR. WSG-ADAPT-TP demonstrated that such de-escalation trials in HER2+ EBC are feasible and safe for patients. Patient selection on the basis of biomarkers or molecular subtypes may increase the efficacy of systemic chemotherapy-free HER2-targeted approaches.

Endocrine Therapy Response and 21-Gene Expression Assay for Therapy Guidance in HR+/HER2- Early Breast Cancer.

PURPOSE: To our knowledge, WSG-ADAPT-HR+/HER2- (ClinicalTrials.gov identifier: NCT01779206; n = 5,625 registered) is the first trial combining the 21-gene expression assay (recurrence score [RS]) and response to 3-week preoperative endocrine therapy (ET) to guide systemic therapy in early breast cancer. MATERIALS AND METHODS: Baseline and postendocrine Ki67 (Ki67post) were evaluated centrally. In the endocrine trial, all patients received exclusively ET: patients with pathologic regional lymph node status (pN) 0-1 (ie, 0-3 involved lymph nodes) entered control arm if RS ≤ 11 and experimental arm if RS12-25 with ET response (Ki67post ≤ 10%). All other patients (including N0-1 RS12-25 without ET response) received dose-dense chemotherapy (CT) followed by ET in the CT trial. Primary end point of the endocrine trial was noninferiority of 5-year invasive disease-free survival (5y-iDFS) in experimental (v control) arm; secondary end points included distant DFS, overall survival, and translational research. RESULTS: Intention-to-treat population comprised 2,290 patients (n = 1,422 experimental v n = 868 control): 26.3% versus 34.6% premenopausal and 27.4% versus 24.0% pN1. One-sided 95% lower confidence limit of the 5y-iDFS difference was -3.3%, establishing prespecified noninferiority (P = .05). 5y-iDFS was 92.6% (95% CI, 90.8 to 94.0) in experimental versus 93.9% (95% CI, 91.8 to 95.4) in control arm; 5-year distant DFS was 95.6% versus 96.3%, and 5-year overall survival 97.3% versus 98.0%, respectively. Differences were similar in age and nodal subgroups. In N0-1 RS12-25, outcome of ET responders (ET alone) was comparable with that of ET nonresponders (CT) for age > 50 years and superior for age ≤ 50 years. ET response was more likely with aromatase inhibitors (mostly postmenopausal) than with tamoxifen (mostly premenopausal): 78.1% versus 41.1% (P < .001). ET response was 78.8% in RS0-11, 62.2% in RS12-25, and 32.7% in RS > 25 (n = 4,203, P < .001). CONCLUSION: WSG-ADAPT-HR+/HER2- demonstrates that guiding systemic treatment by both RS and ET response is feasible in clinical routine and spares CT in pre- and postmenopausal patients with ≤ 3 involved lymph nodes.