Background It is unclear whether some patients with high-risk breast cancer do not warrant adjuvant dose-dense chemotherapy due to small expected absolute benefit. Methods The phase 3 PANTHER trial (NCT00798070) compared adjuvant sequential epirubicin/cyclophosphamide (EC) and docetaxel (D) administered in either tailored dose-dense (tDD EC/D) or standard interval schedule (FEC/D) to patients with high-risk resected early breast cancer (n = 2003). We compared outcomes across key subgroups of interest, evaluated the performance of the online prognostication and treatment benefit estimation tool PREDICT and conducted a subpopulation treatment effect pattern plot (STEPP) analysis. Primary endpoint was breast cancer recurrence free survival (BCRFS). Findings Median follow-up was 10.3 years. Treatment with tDD EC/D improved 10-year BCRFS across all subgroups including according to menopausal status, with an absolute benefit of 2% or more, as well as in luminal (Hazard Ratio [HR] = 0.83, 95% Confidence Interval [CI] 0.65-1.05) and Human Epidermal Growth Factor Receptor 2 (HER2) positive (HR = 0.53, 95% CI 0.30-0.93), but not triple negative breast cancer patients (HR = 1.02, 95% CI 0.66-1.57). PREDICT underestimated overall survival in the entire population and across all subgroups. In STEPP analysis, absolute benefit from tDD EC/D in BCRFS was stable across risk-defined subpopulations, from 3.8% in the lowest risk patients to 3.6% in the highest risk ones. There was no differential treatment effect over time. Interpretation We could not reliably identify any subgroup not benefiting from dose-dense treatment, which should be considered for patients with primary resected high-risk breast cancer. Funding Cancerfonden, Br & ouml;stcancerf & ouml;rbundet, Radiumhemmets Forskningsfonder, Amgen, Roche, sanofi-aventis. Copyright (c) 2024 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Introduction: The presence of axillary lymph node involvement is an important prognostic factor and has a major impact on treatment decisions in early breast cancer patients. This study aimed to determine the role of cortical thickness in axillary ultrasound (AUS) as an indicator of lymph node metastasis. Methods: 766 patients with primary breast cancer who received AUS during clinical work-up were selected for this retrospective study. Lymph nodes were defined as suspicious if they showed a cortical thickness of >3.0 mm at 11-15 MHz harmonic imaging ultrasound. Lymph node involvement was assessed by core needle biopsy (n = 150), sentinel node dissection or axillary dissection. Extensive axillary spread (EAS) was diagnosed if more than two lymph nodes showed metastatic disease in histology. Results: AUS for detecting all lymph node metastases had a sensitivity of 62.27%, a specificity of 93.15% and a negative predictive value of 81.74%. However, the resulting negative predictive value for transcapsular growth was 93.97%, and for EAS 97.52%. Conclusion: EAS - in contrast to non-palpable involvement of 1 or 2 lymph nodes - contributes relevantly to the individualization of breast cancer treatment. In combination with SNB, AUS using cortical thickness as the main distinctive parameter seems to be an easily available, robust tool of diagnosing extensive axillary metastases. If AUS proves negative, it helps to reduce the number of classic axillary dissections.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported. Although dose-dense adjuvant chemotherapy administered once every 2 weeks leads to superior outcomes compared with standard regimens once every 3 weeks, the observed improvement is largely limited to studies using the suboptimal paclitaxel schedule once every 3 weeks as control. PANTHER is an international phase III trial which compared sequential epirubicin/cyclophosphamide and docetaxel administered either once every 2 or once every 3 weeks, with tailored dosing at the dose-dense schedule according to hematologic toxicity. In this end-of-study analysis, the median follow-up was 10.3 years. Compared with standard adjuvant chemotherapy, dose-dense treatment improved breast cancer recurrence-free survival (hazard ratio [HR], 0.80 [95% CI, 0.65 to 0.98]; P = .030), event-free survival (HR, 0.78 [95% CI, 0.65 to 0.94]; P = .009), and distant disease-free survival (HR, 0.79 [95% CI, 0.64 to 0.98]; P = .030) while the improvement in overall survival was not statistically significant (HR, 0.82 [95% CI, 0.65 to 1.04]; P = .109). To our knowledge, this is the first trial that confirms the benefit of a dose-dense regimen over a control regimen containing docetaxel once every 3 weeks.

GAIN-2 trial evaluated the optimal intense dose-dense (idd) strategy for high-risk early breast cancer. This study reports the secondary endpoints pathological complete response (pCR) and overall survival (OS). Patients (n = 2887) were randomized 1:1 between idd epirubicin, nab-paclitaxel, and cyclophosphamide (iddEnPC) versus leukocyte nadir-based tailored regimen of dose-dense EC and docetaxel (dtEC-dtD) as adjuvant therapy, with neoadjuvant therapy allowed after amendment. At median follow-up of 6.5 years (overall cohort) and 5.7 years (neoadjuvant cohort, N = 593), both regimens showed comparable 5-year OS rates (iddEnPC 90.8%, dtEC-dtD 90.0%, p = 0.320). In the neoadjuvant setting, iddEnPC yielded a higher pCR rate than dtEC-dtD (51.2% vs. 42.6%, p = 0.045). Patients achieving pCR had significantly improved 5-year iDFS (88.7% vs. 70.1%, HR 0.33, p < 0.001) and OS rates (93.9% vs. 83.1%, HR 0.32, p < 0.001), but OS outcomes were comparable regardless of pCR status. Thus, iddEnPC demonstrates superior pCR rates compared to dtEC-dtD, yet with comparable survival outcomes.

Background: Dual anti-HER2-targeted therapy in breast cancer (BC) significantly increased the rate of pathological complete response (pCR) compared to single blockade when added to chemotherapy. However, limited data exist on the long-term impact on survival of the additional increase in pCR.Methods: Neoadjuvant lapatinib and/or trastuzumab treatment optimisation (NCT00553358) is an international, randomised, open-label, phase III study investigating the addition of lapa-tinib to chemotherapy plus trastuzumab in HER2-positive early BC. Ten-year event-free sur-vival (EFS), overall survival (OS) and safety were assessed on intention-to-treat population. The association between pCR and EFS or OS was investigated in landmark population.Results: A total of 455 patients were randomised to receive lapatinib (154), trastuzumab (149) or the combination (152). Ten-year EFS estimates were 63% (95% confidence interval [CI], 54%-71%) in the lapatinib group, 64% (95% CI, 55%-72%) in the trastuzumab group and 67% (95% CI, 58%-74%) in the combination group. Ten-year OS rates were 76% (95% CI, 67%-83%), 75% (95% CI, 66%-82%) and 80% (95% CI, 73%-86%) in the lapatinib, trastuzumab and combination groups, respectively. Women who achieved a pCR had improved EFS (hazard ratio 0.48, 95% CI, 0.31-0.73) and OS (hazard ratio 0.37, 95% CI, 0.20-0.63) compared with those who did not. The numerical difference in survival according to pCR status was greater in women treated with the combination and those with hormone -receptor-negative tumours. There were no new or long-term safety concerns. Conclusions: Patients with HER2-positive BC showed a durable survival benefit of neoadju-vant anti-HER2, irrespective of treatment arm. Patients who achieve pCR have significantly better outcomes than patients without pCR.(c) 2022 Elsevier Ltd. All rights reserved.

Estrogen receptor-positive breast cancer is a highly prevalent but heterogeneous disease among women. Advanced molecular stratification is required to enable individually most efficient treatments based on relevant prognostic and predictive biomarkers. First objective of our study was the hypothesis-driven discovery of biomarkers involved in tumor progression upon xenotransplantation of Luminal breast cancer into humanized mice. The second objective was the marker validation and correlation with the clinical outcome of Luminal breast cancer disease within the GeparTrio trial. An elevated mdm2 gene copy number was associated with enhanced tumor growth and lung metastasis in humanized tumor mice. The viability, proliferation and migration capacity of inherently mdm2 positive breast cancer cells in vitro were significantly reduced upon mdm2 knockdown or anti-mdm2 targeting. An mdm2 gain significantly correlated with a worse DFS and OS of Luminal breast cancer patients, albeit it was also associated with an enhanced preoperative pathological response rate. We provide evidence for an enhanced Luminal breast cancer stratification based on mdm2. Moreover, mdm2 can potentially be utilized as a therapeutic target in the Luminal subtype.

Background: GeparOcto demonstrated that pathological complete response (pCR) of intense dose-dense epirubicin, paclitaxel and cyclophosphamide (iddEPC) was comparable to weekly paclitaxel/non-pegylated liposomal doxorubicin (plus carboplatin (PM(Cb) in triple negative breast cancer [TNBC]) in high-risk early breast cancer (BC). Here, we report time-to event secondary end-points. Patients and methods: Patients were randomised to receive 18 weeks of E (150 mg/m(2)) followed by P (225 mg/m(2)) followed by C (2000 mg/m2), each q2w or weekly P (80 mg/m(2)) plus M (20 mg/m2) plus, in TNBC, Cb (AUC 1.5). Patients with human epidermal growth factor receptor 2-positive (HER2+)BC received trastuzumab (6[loading dose 8]mg/kg q3w) and pertuzumab (420[840]mg q3w) with P and C cycles. Results: 945 patients started treatment (iddEPC n = 470; PM(Cb) n = 475). After a median follow-up of 47.0 (range 1.6-61.5) months, 162 (75 in iddEPC; 87 in PM(Cb)) invasive disease-free survival (iDFS) events and 79 (41 in iddEPC; 38 in PM(Cb)) deaths were reported. No significant difference was observed in 4-year iDFS (81.9% iddEPC versus 79.7% PM(Cb), HR = 1.16 [95%CI 0.85-1.59], log-rank p = 0.334) or 4-year overall survival (OS) (90.3% iddEPC versus 90.6% PM(Cb), HR = 0.90 [95%CI 0.58-1.40], log-rank p = 0.637) overall and in HER2+ and TNBC subgroups. HR+/HER2BC patients, however, had significantly better 4-year iDFS (77.9% iddEPC versus 62.5% PM, HR = 2.11 [95%CI 1.08-4.10], log-rank p = 0.025) and 4-year OS with iddEPC (94.7% iddEPC versus 80.1% PM, HR = 3.26 [95%CI 1.06-10.00], log-rank p = 0.029). Conclusion: While there was no difference in survival for the entire cohort, the HR+/HER2subgroup significantly benefits from iddEPC. This supports the concept of an additional effect of NACT beyond pCR in patients with HR+/HER2 - BC. (C) 2021 Elsevier Ltd. All rights reserved.

Background: Trastuzumab given intravenously in combination with chemotherapy is standard of care for patients with early HER2-positive breast cancer (BC). Different randomised studies have shown equivalent efficacy of a subcutaneous injection into the thigh compared to the intravenous formulation. Other body regions for injection have not been investigated but might be more convenient for patients.Methods: After surgery, patients were randomised to receive either subcutaneous trastuzumab into the thigh or into the abdominal wall (AW). Patient preferences were evaluated using validated questionnaires (PINT). Pri-mary objectives of this multicentre, non-blinded, randomised substudy of the GAIN-2 study were to investigatepharmacokinetics of the injection into the thigh versus AW and to determine patients' preferences of either administration site versus the previously received intravenous application.Results: 226 patients were randomised and 219 patients (thigh: N = 110; AW: N = 109) formed the modified intent-to-treat (mITT). Overall, 83.5% (out of N = 182 with information about patients' preference) preferred subcutaneous over previous intravenous application or had no preference. Preference was similar between both administration sites (thigh: 80.6%; AW: 86.5; p = 0.322). Pharmacokinetic analysis included 30 patients. Geo-metric means of Cmax and AUC0-21d were higher in thigh than in AW group (geometric mean ratio with body weight adjustment: Cmax: 1.291, 90%-CI 1.052-1.584; AUC0-21d: 1.291, 90%-CI 1.026-1.626). Safety profile was in line with previous reports of subcutaneous trastuzumab.Conclusion: Subcutaneous trastuzumab into the thigh showed an approximately 30% higher bioavailability. In-jections were well tolerated and preferred over intravenous administration. The subcutaneous injection into the thigh should remain the standard of care.

Background: Despite the large number of patients with early breast cancer (EBC) who have been treated with capecitabine in randomised trials, no individual patient data metaanalysis has been conducted. The primary objective was to examine the effect of capecitabine on disease-free survival (DFS), and the secondary objectives were to analyse distant DFS (DDFS), overall survival (OS), pathological complete response (for neoadjuvant studies) and the interaction between capecitabine-related toxicity and treatment effect. Methods: www.clinicaltrials.gov and www.pubmed.ncbi.nlm.nih.gov were searched using the following criteria: use of capecitabine for EBC as adjuvant or neoadjuvant therapy; multicentre randomised trial with >100 patients; recruitment completed, and outcomes available. Required data were available for 13 trials. Results: Individual data from 15,993 patients were collected. Cox regression analyses of all included patients revealed that the addition of capecitabine did not alter DFS significantly compared with treatment without capecitabine (hazard ratio [HR] 0.952; 95% CI 0.895-1. 012; P value = 0.115). There was also no effect on DFS in the subset of studies where capecitabine was given instead of another drug (HR 1.035; 95% CI 0.945-1.134; P = 0. 455). However, capecitabine administered in addition to the standard systemic treatment improved DFS (HR 0.888; 95% CI 0.817-0.965; P = 0.005). An OS improvement was observed in the entire cohort (HR 0.892; 95% CI 0.824-0.965, P = 0.005) and in the subset of capecitabine addition (HR 0.837; 95% CI 0.751, 0.933, P = 0.001). Subgroup analyses revealed that triple- negative breast cancer (TNBC) patients benefitted from treatment with capecitabine overall and in addition to other systemic treatments in terms of DFS and OS. Conclusion: Capecitabine was able to improve DFS and OS in patients with TNBC and in all patients with EBC when administered in addition to systemic treatment. (c) 2022 Elsevier Ltd. All rights reserved.

Background: The conversion of initially histologically confirmed axillary lymph node-positive (pN+) to ypN0 after neoadjuvant systemic treatment (NAST) is an important prognostic factor in breast cancer (BC) patients and may influence surgical de-escalation strategies. We aimed to determine pCR rates in lymph nodes (pCR-LN), the breast (pCR-B), and both (tpCR) in women who present with pN+ BC, to assess predictors for response and the impact of pCR-LN, pCR-B, and tpCR on invasive disease-free survival (iDFS). Methods: Retrospective, exploratory analysis of 242 patients with pN+ at diagnosis from the multicentric, randomized GeparOcto trial. Results: Of 242 patients with initially pN+ disease, 134 (55.4%) had a pCR-LN, and 109 (45.0%) a pCR-B. Of the 109 pCR-B patients, 9 (8.3%) patients had involved LN, and 100 (41.3%) patients had tpCR. Those with involved LN still had a bad prognosis. As expected, pCR-B and intrinsic subtypes (TNBC and HER2+) were identified as independent predictors of pCR-LN. pCR-LN (ypN0; hazard ratio 0.42; 95%, CI 0.23–0.75; p = 0.0028 for iDFS) was the strongest independent prognostic factor. Conclusions: In initially pN+ patients undergoing NAST, the conversion to ypN0 is of high prognostic value. Surgical axillary staging after NAST is still essential in these patients to offer tailored treatment.

[This corrects the article DOI: 10.1055/a-1499-8431.].

Abstract Background: In HER2-positive breast cancer patients, timing from the end of (neo)adjuvant trastuzumab (T)-based therapy to diagnosis of metastatic breast cancer is the key factor in determining the optimal first-line treatment. There is currently lack of clear evidence to support the possible prognostic role of this interval and 12 months has been mostly empirically used. The present analysis aimed to investigate patterns of relapse, first-line choice and survival outcomes of patients with HER2-positive early breast cancer who relapsed after adjuvant T-based therapy depending on T-free interval (TFI, i.e. timing from end of adjuvant T to diagnosis of distant metastases). Methods: In ALTTO, HER2-positive early breast cancer patients were randomized to 1 year of either T alone, lapatinib (L) alone, their sequence (T–>L) or their combination (T+L). This exploratory analysis included only pts in the T or T+L arms who experienced a distant disease-free survival (DDFS) event. Two cohorts of patients were defined depending on TFI: group A (TFI of <12 months) and group B (>12 months). Baseline characteristics, patterns of relapse, first-line choice and overall survival (OS) were compared. OS was defined as time between date of DDFS event to death; age at diagnosis, tumor size and hormone receptor status were the variables included in the final multivariate models. Results: Out of 8,381 patients included in ALTTO, 404 patients in the T and T+L arms developed a DDFS event, of whom 201 occurred <12 months (group A) and 203 >12 months (group B) after the end of adjuvant T. Patients in group A were older (p=0.013), had larger tumors (p=0.004) and more frequently hormone receptor-negative disease (p<0.001). No significant difference in patterns of first DDFS event was observed (p=0.073); however, a numerically higher number of patients in group A compared to group B developed brain metastasis (26% vs. 15%). First-line anti-HER2 therapy was received by 57% of the patients. Choice of first-line anti-HER2 therapy was different between the two groups (p=0.022): the majority of patients received T in both groups (61% vs. 65% in groups A and B, respectively), while more patients in group A received L (25% vs. 11%) and less received pertuzumab (8% vs. 17%). OS survival was significantly shorter in group A compared to group B: median OS was 18.4 and 29.3 months in groups A and B, respectively (adjusted HR 0.69; 95% CI 0.54-0.89; p=0.004). Similar results were observed after the exclusion of patients treated with first-line pertuzumab-based therapy (n=29): median OS was 18.2 and 26.8 months in groups A and B, respectively (adjusted HR 0.66; 95% CI 0.51-0.86; p=0.002). Better outcomes in terms of OS for patients in group B was observed across all analyzed subgroups with no interaction according to hormone receptor status (p=0.814) nor type of adjuvant anti-HER2 treatment (p=0.233): hormone receptor-positive (adjusted HR 0.69; 95% CI 0.48-0.99), hormone receptor-negative (adjusted HR 0.68; 95% CI 0.48-0.98), T+L arm (adjusted HR 0.55; 95% CI 0.38-0.80) and T arm (adjusted HR 0.80; 95% CI 0.55-1.17). Conclusions: In the ALTTO trial, HER2-positive early breast cancer patients who experienced shorter TFI (i.e. <12 months vs. >12 months) following adjuvant T-based therapy had inferior OS after the diagnosis of distant recurrence. Given its prognostic value, TFI can help to individualize clinical recommendations and to design future trials in the metastatic setting for patients relapsing after prior exposure to anti-HER2 therapy for early disease. Citation Format: Matteo Lambertini, Dominique Agbor-Tarh, Otto Metzger-Filho, Noam Ponde, Francesca Poggio, Florentine Hilbers, Larissa A Korde, Saranya Chumsri, Olena Werner, Lucia Del Mastro, Rafael Caparica, Volker Moebus, Alvaro Moreno-Aspitia, Martine Piccart, Evandro de Azambuja. Prognostic role of distant disease-free interval from completion of adjuvant trastuzumab in HER2-positive early breast cancer: Analysis from the ALTTO (BIG 2-06) trial [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 PD3-04.

Background: The GAIN-2 trial was designed to identify a superior intense dose dense (idd) strategy for high-risk patients with early breast cancer. Here, we report an interim analysis, at which the predefined futility boundary was crossed. Patients and methods: GAIN-2 was an open-label, randomised, multicentre phase III trial. Two thousand eight hundred and eighty seven patients were randomised 1:1 between three courses each of idd epirubicin (E) 150 mg/m(2), nab-paclitaxel (nP) 330 mg/m(2) and cyclophosphamide (C) 2000 mg/m(2) (iddEnPC) versus four cycles of leucocyte nadir-based tailored and dose-dense EC (dtEC) followed by four cycles of tailored and dose-dense docetaxel (dtD) (dtEC-dtD). Results: The duration of median follow-up was 45.8 (range 0.0-88.3) months. Trial objectives included invasive disease-free survival (iDFS) as the primary end-point. A total of 593 patients received the treatment as neoadjuvant chemotherapy. At the time of futility interim analysis, 414 events for iDFS were reported. Overall, there was no difference in iDFS between iddEnPC and dtEC-dtD with 4-year iDFS rates of 84.3% (95% confidence interval (CI) 82.0-86.4%). Among all predefined subgroups, hormone receptor-positive and human epidermal growth factor receptor 2-negative (HR+/HER2-), lobular cancer and <= 50 years subgroups predicted for better iDFS in the dtEC-dtD arm. Overall, 88.1% of patients completed all treatment in both arms. Haematological toxicity grade 3/4 and grade 3/4 non-haematological adverse events were significantly higher with iddEnPC (iddEnPC 50.8% vs dtEC-dtD 45.1%, P = 0.002), especially arthralgia and peripheral sensory neuropathy. Two treatment-related deaths occurred during dtEC-dtD, corresponding to a low mortality rate of 0.07%. Conclusions: iDFS is equal in both regimens, but tailoring dose-dense chemotherapy improved outcomes in HR+/HER2-, lobular cancer and patients <= 50 years. (C) 2021 Elsevier Ltd. All rights reserved.

Background: Lapatinib (L) plus trastuzumab (T) with weekly paclitaxel significantly increased the pathologic complete response (pCR) rate (51.3%) compared with either anti-human epidermal growth factor receptor 2 (HER2) drug alone (24.7%% for L, 29.5% for T). Here, we report the results of the prespecified long-term event-free survival (EFS) and overall survival (OS) analyses by the treatment arms. In addition, we assess the relationship between pCR and survival, both in the overall study population and according to hormone receptor status and treatment arm.

573 Background: GeparOcto compared the efficacy of two neoadjuvant treatment (NAT) regimens in high-risk early breast cancer (BC): Sequential intense dose-dense epirubicin, paclitaxel, and cyclophosphamide (iddEPC) and weekly paclitaxel plus non-pegylated liposomal doxorubicin (PM), plus carboplatin (PMCb) in triple-negative BC (TNBC). There was no difference in pathologic complete response (pCR) rates (Schneeweiss et al. Eur J Cancer 2019). Here, we stratified pCR rates according to germline mutation status. Methods: Germline (g) mutation analysis of BRCA1/2 and 16 further BC predisposition genes in 914 patients (pts) enrolled (393 pts with TNBC, iddEPC n = 194, PMCb n = 199; 156 pts with HER2-/HR+ BC, iddEPC n = 75, PM n = 81; and 365 pts with HER2+ BC, iddEPC n = 182, PM n = 183). Results: The gBRCA1/2 mutation prevalence was 17.6% in TNBC, 14.1% in HER2-/HR+ BC and 1.4% in HER2+ BC. Overall, pts with gBRCA1/2 mutations achieved higher pCR rates than gBRCA1/2 wildtype pts (60.4% vs 46.7%, OR 1.74, P = 0.012), with more pronounced effects in the PM(Cb) arm (68.1% vs 45.7%, OR 2.53, P = 0.005). Among gBRCA1/2 wildtype pts, 76 carried mutations in non- BRCA1/2 predisposition genes. pCR rates were similar to those observed in pts without any mutation. Conclusions: Pts with gBRCA1/2 mutations benefitted most from NAT with highest pCR rates achieved in the gBRCA1/2 TNBC / PMCb group. The role of Cb for NAT of gBRCA1/2 TNBC should be further explored. Clinical trial information: NCT02125344. [Table: see text]

GeparOcto investigated dose-dense NACT with intense dose-dense epirubicin, paclitaxel, cyclophosphamide (iddEPC) and PM(Cb) in high-risk early BC. Primary endpoint pathological complete response (pCR; ypT0/is ypN0) was comparable in the whole cohort as well as in subgroups (Schneeweiss et al. EJC 2019). Here, we report the secondary endpoints invasive disease-free survival (iDFS) and overall survival (OS). Pts were randomized (stratified by BC subtype, Ki67, lymphocyte-predominant BC) to receive 18 weeks of E (150 mg/m2) followed by P (225 mg/m2) followed by C (2000 mg/m2), each q2w for 3 cycles or weekly P (80 mg/m2) plus M (20 mg/m2) plus, in TNBC, Cb (AUC 1.5). HER2+ BC pts additionally received trastuzumab (6 [loading dose 8]mg/kg q3w) and pertuzumab (420 [840]mg q3w) with all P and C cycles. Adjuvant locoregional and endocrine therapy were given according to national guidelines. Secondary time-to-event endpoints were iDFS and OS. Between 12/2014 and 06/2016, a total of 961 pts were randomized and 945 started treatment (iddEPC n=470, PM(Cb) n=475). After a median follow-up of 47.0 (range 1.6-61.5) months, 75 iDFS events in iddEPC and 87 in PM(Cb) were reported. Overall, there was no difference in iDFS (hazard ratio PM(Cb) to iddEPC 1.16, 95%CI 0.85-1.59, p=0.3357) or OS (hazard ratio 0.90, 95%CI 0.58-1.40, p=0.6371) between both arms. In the subgroup of hormone-receptor (HR)+/HER2- BC, iDFS was significantly longer for iddEPC (4-year iDFS 62.5% with PM vs.77.9% with iddEPC; hazard ratio 2.11, 95%CI 1.08-4.10, p=0.0284), translating into an OS benefit (4-year OS 80.1% vs. 94.7%; hazard ratio 3.26, 95%CI 1.06-10.00, p=0.0388). There was no significant difference in survival in HER2+ or TNBC. While there was no difference in survival following NACT with iddEPC or PM(Cb) for the entire cohort, the subgroup of HR+/HER2- BC significantly benefits from treatment with iddEPC. This supports the concept of effective therapy beyond pCR in luminal BC pts.

BackgroundIn HER2-positive breast cancer, time elapsed between completion of (neo)adjuvant trastuzumab and diagnosis of metastatic disease (‘trastuzumab-free interval’, TFI) is crucial to choose the optimal first-line treatment. Nevertheless, there is no clear evidence to support its possible prognostic role.MethodsIn the Adjuvant Lapatinib and/or Trastuzumab Treatment Optimisation (ALTTO) trial, patients with HER2-positive early breast cancer were randomised to 1 year of either trastuzumab alone, lapatinib alone, their sequence or their combination. This exploratory analysis included only patients in the trastuzumab alone or trastuzumab plus lapatinib arms who developed a distant disease-free survival (DDFS) event. Overall survival (OS) was defined as time between date of DDFS event and death; age at diagnosis, tumour size and hormone receptor status were the variables included in the multivariate models.ResultsOut of 8381 patients included in ALTTO, 404 patients in the trastuzumab alone and trastuzumab plus lapatinib arms developed a DDFS event, of which 201 occurred <12 months (group A) and 203 >12 months (group B) after completion of adjuvant trastuzumab. No significant difference in location of first DDFS event was observed (p=0.073); a numerically higher number of patients in group A than in group B developed brain metastasis (26% vs 15%). Choice of first-line therapy differed between the two groups (p=0.022): in group A, more patients received lapatinib (25% vs 11%) and less pertuzumab (8% vs 17%). Median OS was 29.3 and 18.4 months in groups B and A, respectively (adjusted HR 0.69; 95% CI 0.54–0.89; p=0.004). The longer OS for patients in group B was observed across the analysed subgroups without interaction according to hormone receptor status (p=0.814) nor type of administered adjuvant anti-HER2 treatment (p=0.233).ConclusionsTFI has prognostic value in patients with HER2-positive early breast cancer treated with adjuvant trastuzumab-based therapy. TFI is a valid tool to better individualise clinical recommendations and to design future first-line treatment trials for metastatic patients.