HER2-positive Early Breast Cancer Patients Research Articles

Abstract PO1-01-02: Final analysis of neoadjuvant chemotherapy with pegylated liposomal doxorubicin/cyclophosphamide followed by taxanes with full-course trastuzumab/pertuzumab for HER2-positive breast cancer: a single-arm, phase II study

Abstract Background: The optimal neoadjuvant treatment regimen for HER2-positive breast cancer remains unclear, especially regarding the use of anthracycline. We conducted a prospective phase II study to evaluate sequential neoadjuvant chemotherapy with pegylated liposomal doxorubicin (PLD)/cyclophosphamide followed by taxanes in the presence of full-course trastuzumab/pertuzumab in HER2-positive early breast cancer patients. Methods: In this single-arm, open-label, multicenter, phase II study, eligible patients with confirmed HER2-positive early breast cancer were recruited from four independent hospitals. Patients received four cycles of PLD (35 mg/m2) and cyclophosphamide (600 mg/m2), followed by four cycles of taxanes (docetaxel, 100 mg/m2 or nab-paclitaxel, 260 mg/m2), concomitant with eight cycles of trastuzumab (8 mg/kg loading dose, then 6 mg/kg) and pertuzumab (840 mg loading dose, then 420 mg) every 3 weeks. The primary endpoint was total pathological complete response (ypT0/is ypN0, tpCR). Secondary endpoints included breast pCR (bpCR), objective response rate (ORR), disease control rate, the proportion of patients requiring breast-conserving surgery, and safety. For biomarkers analysis, tumor tissues were collected at baseline and evaluated for Topoisomerase 2 Alpha (TOP2A) expression assessed prospectively with immunohistochemistry (IHC) assay by independent pathologists. Results: Between May 27, 2020 and May 11, 2022, 78 eligible patients were treated and underwent surgery, of whom 42 (53.8%) patients underwent breast-conserving surgery. After neoadjuvant therapy, 47 (60.3%, 95% CI, 48.5%-71.2%) patients achieved a tpCR in the breast and axilla. The bpCR was observed in 49 (62.8%) patients. ORRs were 76.9% (95% CI, 66.0%-85.7%) and 93.6% (95% CI, 85.7%-97.9%) after 4-cycle and 8-cycle neoadjuvant therapy, respectively. All (100%) patients achieved disease control since the end of the first cycle. No correlations between clinicopathological variables and pathological response were observed. Grade 3 or worse AEs occurred in 35 (44.9%) patients. Nine (11.5%) patients experienced asymptomatic LVEF reduction (≥10% from baseline), but all with a minimum value of >55%. No treatment-related surgical delay or death occurred. For biomarkers analysis, the status of TOP2A was not found to be associated with pCR or 4th-cycle ORR. Conclusions: This dual HER2-blockade plus polychemotherapy as sequential neoadjuvant regimen demonstrates promising anti-tumor activity and acceptable tolerability for patients with HER2-positive breast cancer. Citation Format: Yaping Yang, Liang Jin, Yudong li, Fengxia Gan, Nanyan Rao, Jun Zhang, Ruifa Feng, Zhenzhen Liu, Qiang Liu. Final analysis of neoadjuvant chemotherapy with pegylated liposomal doxorubicin/cyclophosphamide followed by taxanes with full-course trastuzumab/pertuzumab for HER2-positive breast cancer: a single-arm, phase II study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-01-02.

Abstract CT029: Chemotherapy-free neoadjuvant regimen with durvalumab, trastuzumab and pertuzumab (DTP) in HER2-enriched early breast cancer: A prospective, open-label phase II trial

Abstract Background: High risk HER2-positive early breast cancer (EBC) patients are traditionally treated with neoadjuvant chemotherapy in combination with HER2-directed therapy. De-escalation approaches are being studied as benefits of chemotherapy in the HER2-enriched subset of EBC, but they have been inconclusive thus far. Preclinical studies suggest synergistic effect of immune checkpoint blockade (ICB) and HER2-directed therapy. This study hypothesizes that biologically directed HER-2 targeted therapy with Trastuzumab (T) and Pertuzumab (P) together with ICB (Durvalumab, D) will obviate the need of chemotherapy in HER2-enriched EBC patients. Methods: In this single arm, open-label phase II study, previously untreated, stage I-III, ER/PR negative, HER2-enriched breast cancer (BluePrint®, Agendia) patients were treated with D (1120mg IV, q3w), T (8mg/kg IV loading dose, 6 mg/kg IV q3w), and P (840 mg IV loading dose, 420 mg IV q3w) for 6 cycles. Response was assessed at end of 6 cycles with breast MRI and possible biopsy if residual disease was present. Responders (MRI and/or biopsy negative for residual cancer) proceeded to surgery, while patients with biopsy-proven residual disease were offered salvage standard chemotherapy (TCHP) before surgery. Primary end-point was pathological response rate defined as residual cancer burden (RCB)-0 and RCB-1. Patients who achieved RCB 0/1 received adjuvant DTP for 1 year. Results: A total of 51 patients were screened; 39 patients have been enrolled and received at least one cycle of treatment. Of these, 35 patients are evaluable for pathologic response, and 2 patients are still receiving treatment. One patient died of unrelated myocardial infarction, and one patient was lost to follow-up. The median age was 55 years (range 29-85). Thirty-one (79.5%) patients were white; 4 (10.3%) African American, and 4 (10.3%) Asian. Twenty-nine (74.3%) patients had >=T2 tumors; 21 (53.8%) patients had N1/N2/N3 disease. Six patients (15.3%) had biopsy-proven residual disease after DTP therapy, and they received salvage standard neoadjuvant TCHP chemotherapy. The combination was well tolerated; 5 (18.8%) patients had G3-4 adverse events. Twenty-seven of thirty-five patients (77.1%) had pathologic RCB 0/1 (RCB0, 20/35; RCB1 7/35), of whom only 3 patients had received salvage chemotherapy. Correlative studies, including tumor-infiltrating lymphocytes, immune-related gene signatures and PD-L1 expression are underway. Conclusions: Chemotherapy-free neoadjuvant regimen with DTP in HER2-enriched EBC showed high pathologic response rates comparable to that with chemotherapy. This DTP regimen may provide an effective, relatively non-toxic, and biologically driven alternative to standard of care chemotherapy in this HER2-enriched subset of EBC. Citation Format: Jian Guan, Kai Sun, Dharamvir Jain, Sunil Mathur, Hanh Mai, Polly Niravath, Jenny Chang. Chemotherapy-free neoadjuvant regimen with durvalumab, trastuzumab and pertuzumab (DTP) in HER2-enriched early breast cancer: A prospective, open-label phase II trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT029.

Optimal [18F]FDG PET/CT Cutoff for Pathologic Complete Response in HER2-Positive Early Breast Cancer Patients Treated with Neoadjuvant Trastuzumab and Pertuzumab in the PHERGain Trial.

The PHERGain trial investigated the potential of metabolic imaging to identify candidates for chemotherapy deescalation in human epidermal growth factor receptor 2 (HER2)-positive, invasive, operable breast cancer with at least 1 breast lesion evaluable by [18F]FDG PET/CT. [18F]FDG PET/CT responders were defined as patients with an SUVmax reduction (ΔSUVmax) of at least 40% in all of their target lesions after 2 cycles of trastuzumab and pertuzumab (HP) (with or without endocrine therapy). In total, 227 of 285 patients (80%) included in the HP arm showed a predefined metabolic response and received a total of 8 cycles of HP (with or without endocrine therapy). Pathologic complete response (pCR), defined as ypT0/isN0, was achieved in 37.9% of the patients. Here, we describe the secondary preplanned analysis of the best cutoff of ΔSUVmax for pCR prediction. Methods: Receiver-operating-characteristic analysis was applied to look for the most appropriate ΔSUVmax cutoff in HER2-positive early breast cancer patients treated exclusively with neoadjuvant HP (with or without endocrine therapy). Results: The ΔSUVmax capability of predicting pCR in terms of the area under the receiver-operating-characteristic curve was 72.1% (95% CI, 65.1-79.2%). The optimal ΔSUVmax cutoff was found to be 77.0%, with a 51.2% sensitivity and a 78.7% specificity. With this cutoff, 74 of 285 patients (26%) would be classified as metabolic responders, increasing the pCR rate from 37.9% (cutoff ≥ 40%) to 59.5% (44/74 patients) (P < 0.01). With this optimized cutoff, 44 of 285 patients (15.4%) would avoid chemotherapy in either the neoadjuvant or the adjuvant setting compared with 86 of 285 patients (30.2%) using the original cutoff (P < 0.001). Conclusion: In the PHERGain trial, an increased SUVmax cutoff (≥77%) after 2 cycles of exclusive HP (with or without endocrine therapy) achieves a pCR in the range of the control arm with chemotherapy plus HP (59.5% vs. 57.7%, respectively), further identifying a subgroup of patients with HER2-addicted tumors. However, the original cutoff (≥40%) maximizes the number of patients who could avoid chemotherapy.

3-year invasive disease-free survival with chemotherapy de-escalation using an 18F-FDG-PET-based, pathological complete response-adapted strategy in HER2-positive early breast cancer (PHERGain): a randomised, open-label, phase 2 trial

PHERGain was designed to assess the feasibility, safety, and efficacy of a chemotherapy-free treatment based on a dual human epidermal growth factor receptor 2 (HER2) blockade with trastuzumab and pertuzumab in patients with HER2-positive early breast cancer (EBC). It used an 18fluorine-fluorodeoxyglucose-PET-based, pathological complete response (pCR)-adapted strategy. PHERGain was a randomised, open-label, phase 2 trial that took place in 45 hospitals in seven European countries. It randomly allocated patients in a 1:4 ratio with centrally confirmed, HER2-positive, stage I-IIIA invasive, operable breast cancer with at least one PET-evaluable lesion to either group A, where patients received docetaxel (75 mg/m2, intravenous), carboplatin (area under the curve 6 mg/mL per min, intravenous), trastuzumab (600 mg fixed dose, subcutaneous), and pertuzumab (840 mg loading dose followed by 420 mg maintenance doses, intravenous; TCHP), or group B, where patients received trastuzumab and pertuzumab with or without endocrine therapy, every 3 weeks. Random allocation was stratified by hormone receptor status. Centrally reviewed PET was conducted at baseline and after two treatment cycles. Patients in group B were treated according to on-treatment PET results. Patients in group B who were PET-responders continued with trastuzumab and pertuzumab with or without endocrine therapy for six cycles, while PET-non-responders were switched to receive six cycles of TCHP. After surgery, patients in group B who were PET-responders who did not achieve a pCR received six cycles of TCHP, and all patients completed up to 18 cycles of trastuzumab and pertuzumab. The primary endpoints were pCR in patients who were group B PET-responders after two treatment cycles (the results for which have been reported previously) and 3-year invasive disease-free survival (iDFS) in patients in group B. The study is registered with ClinicalTrials.gov (NCT03161353) and is ongoing. Between June 26, 2017, and April 24, 2019, a total of 356 patients were randomly allocated (71 patients in group A and 285 patients in group B), and 63 (89%) and 267 (94%) patients proceeded to surgery in groups A and B, respectively. At this second analysis (data cutoff: Nov 4, 2022), the median duration of follow-up was 43·3 months (range 0·0-63·0). In group B, the 3-year iDFS rate was 94·8% (95% CI 91·4-97·1; p=0·001), meeting the primary endpoint. No new safety signals were identified. Treatment-related adverse events and serious adverse events (SAEs) were numerically higher in patients allocated to group A than to group B (grade ≥3 62% vs 33%; SAEs 28% vs 14%). Group B PET-responders with pCR presented the lowest incidence of treatment-related grade 3 or higher adverse events (1%) without any SAEs. Among HER2-positive EBC patients, a PET-based, pCR-adapted strategy was associated with an excellent 3-year iDFS. This strategy identified about a third of patients who had HER2-positive EBC who could safely omit chemotherapy. F Hoffmann-La Roche.

Abstract 5213: Evaluation of HER2DX risk-score in residual disease (RD) from HER2-positive (HER2+) early breast cancer (EBC) patients (pts) following neoadjuvant trastuzumab and pertuzumab (HP)-based therapy: An exploratory analysis from the PHERGain trial

Abstract Introduction: HER2DX is a prognostic (risk-score) and predictive (pathological complete response-score) genomic assay validated in baseline (BL) tumor samples from HER2+ EBC pts. RD after neoadjuvant anti-HER2-based therapy is associated with worse outcomes. Whether HER2DX risk-score analyzed in RD provides additional prognostic information is unknown. Methods: This retrospective analysis included 14 pts from group B of the PHERGain trial (NCT03161353): 6 who developed distant recurrences and 8 matched controls with HER2DX high-risk score at BL who did not. Group B pts had centrally confirmed, stage I-IIIA, HER2+ EBC and were treated with HP (± endocrine therapy), with chemotherapy added for pts without PET response after 2 treatment cycles or pathological complete response (Perez-Garcia et al, Lancet Oncol 2021).HER2DX was evaluated on tumor samples collected at BL and surgery. The primary objective was to determine the association of HER2DX risk-score in RD with the development of distant recurrences. Secondary objectives were to assess gene expression and the HER2DX signatures in BL vs RD and their association with distant recurrences. Cox regression models evaluated the association of variables with distant recurrence. Paired SAM with a false discovery rate &amp;lt;5% identified differences in gene expression between BL and RD samples. Results: Median follow-up was 4.04 years. Five (83.3%) of 6 pts with distant recurrences had HER2DX high-risk scores at BL. The 8 control pts had HER2DX high-risk scores at BL but no relapse. In RD, all 6 pts (100%) who relapsed had a HER2DX high-risk score, while 4 (50%) of 8 pts without distant recurrence presented a HER2DX downstaging. Pts with HER2DX low-risk in RD had better 3-year distant disease-free survival than high-risk pts (100% vs 50%; hazard ratio = 4.34 [1.03-18.23], p=0.045). In RD, high expression of the proliferation signature and 15 genes, including proliferation genes, and low expression of 38 genes, including immune and luminal-related genes, were associated with poor prognosis. In paired analyses of BL and RD samples, 118 genes (63.8%) were differentially expressed in pts that did not relapse, while only 3 genes (1.6%) were differentially expressed in pts that relapsed. Conclusions: These data suggest that HER2DX risk-score in RD provides additional information on the likelihood of developing distant recurrences. In RD, high expression of immune and luminal genes was associated with a reduced risk, while high expression of proliferation genes was associated with a higher risk. Molecular changes after anti-HER2 therapy were mainly observed in RD of pts that did not relapse. Prognostic impact of HER2DX downstaging merits further evaluation. Citation Format: José Manuel Pérez-García, Fara Brasó-Maristany, Elena Martínez-García, Carmen Mora Gallardo, Eileen Shimizu, Olga Boix Sánchez, Jose Rodríguez-Morató, Mario Mancino, Laia Paré, Guillermo Villacampa, Mercedes Marín-Aguilera, Patricia Galván, Ana Vivancos, Patricia Villagrasa, Joel Parker, Charles M. Perou, Antonio Llombart-Cussac, Javier Cortés, Aleix Prat. Evaluation of HER2DX risk-score in residual disease (RD) from HER2-positive (HER2+) early breast cancer (EBC) patients (pts) following neoadjuvant trastuzumab and pertuzumab (HP)-based therapy: An exploratory analysis from the PHERGain trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5213.

Correlation between trophoblast cell-surface antigen-2 (Trop-2) expression and pathological complete response in patients with HER2-positive early breast cancer treated with neoadjuvant docetaxel, carboplatin, trastuzumab, and pertuzumab.

The prognostic and predictive role of trophoblast cell-surface antigen-2 (Trop-2) overexpression in human epidermal growth factor receptor 2-positive (HER2-positive) breast cancer is currently unknown. We retrospectively analyzed Trop-2 expression and its correlation with clinicopathologic features and pathological complete response (pCR) in HER2-positive early breast cancer (EBC) patients treated with neoadjuvant docetaxel, carboplatin, trastuzumab, and pertuzumab in the PHERGain study. Trop-2 expression at baseline was determined in formalin-fixed, paraffin-embedded primary tumor biopsies by immunohistochemistry and was first classified into expressing (Trop-2-positive) or not-expressing (Trop-2-negative) tumors. Then, it was classified by histochemical score (H-score) according to its intensity into low (0-9), intermediate (10-49), and high (≥ 50). The association between clinicopathologic features, pCR, and Trop-2 expression was performed with Fisher's exact test. Forty-one patients with tissue evaluable for Trop-2 expression were included, with 28 (68.3%) Trop-2-positive tumors. Overall, 17 (41.46%), 14 (34.15%), and 10 (24.40%) tumors were classified as low, intermediate, and high, respectively. Trop-2 expression was significantly associated with decreased pCR rates (50.0% vs. 92.3%; odds ratio [OR] 0.05; 95% CI, 0.002-0.360]; p adjusted = 0.01) but was not correlated with any clinicopathologic features (p ≥ 0.05). Tumors with the highest Trop-2H-score were less likely to obtain a pCR (OR 0.03; 95% CI, 0.001-0.290, p adjusted < 0.01). This association was confirmed in univariate and multivariate regression analyses. These findings suggest a potential role of Trop-2 expression as a biomarker of resistance to neoadjuvant chemotherapy plus dual HER2 blockade and may become a strategic target for future combinations in HER2-positive EBC patients.

Shorter Durations of Anti-HER2 Therapy for Patients with Early-Stage, HER2-Positive Breast Cancer: The Physician Perspective.

Despite evidence from clinical trials showing the efficacy of shorter durations of therapy, most HER2-positive early breast cancer (EBC) patients receive a year of anti-HER2 therapy. A survey of Canadian oncologists was conducted online, with electronic data collection, and the analysis is reported descriptively. Measures collected included current practices with respect to the duration of adjuvant anti-HER2 therapy, perspectives on data regarding shorter durations of treatment, and interest in further trials on this subject. Responses were received from 42 providers across Canada. Half (50%, 21/42) reported having never recommended 6 months of anti-HER2 therapy. The primary reason physicians consider a shorter duration is in response to treatment-related toxicities (76%, 31/41). Most participants (79%, 33/42) expressed the need for more data to determine which patients can be safely and effectively treated with shorter durations. Patient factors such as young age, initial stage, hormone receptor status, and type of neoadjuvant chemotherapy were attributed to reluctance to offer shorter durations of treatment. Many respondents (83%, 35/42) expressed interest in participating in the proposed clinical trial of 6 months of anti-HER2 therapy. In contemporary Canadian practice, 12 months of anti-HER2 therapy remains the primary practice. Future trials are required to better define the role of shorter treatment durations.

EE362 A Budget Impact Analysis of Pertuzumab, Trastuzumab, and Chemotherapy in the Neoadjuvant Setting for HER2-Positive High-Risk Early Breast Cancer Patients: Insights from the Tuscany Regional Health Care System Perspective

EE362 A Budget Impact Analysis of Pertuzumab, Trastuzumab, and Chemotherapy in the Neoadjuvant Setting for HER2-Positive High-Risk Early Breast Cancer Patients: Insights from the Tuscany Regional Health Care System Perspective

123O Randomized phase II trial of neoadjuvant atezolizumab in combination with dual HER2 blockade plus epirubicin in early HER2-positive breast cancer (ABCSG-52/ATHENE)

For most HER2-positive early breast cancer (EBC) patients (pts), neoadjuvant dual HER2 blockade with trastuzumab (T) and pertuzumab (P) plus poly-chemotherapy is standard of care. To improve the balance between toxicity burden and treatment outcomes, chemotherapy de-escalation has been a major focus in recent years. Among other immunogenic properties, anthracyclines can trigger an immunogenic cell death that engages the adaptive immune system. Within the ABCSG-52 trial we investigated a chemotherapy de-escalation immunotherapy regimen in HER2-positive EBC. Pts with previously untreated, histologically confirmed HER2-positive EBC (clinical prognostic stage cT1c-4a-d, N0–3,M0) were randomized 1:1 to two 3-weekly cycles of a chemotherapy-free induction phase (part 1) with TP plus 1200mg atezolizumab (TP+A) or TP alone. Afterwards, all pts received 4 cycles of TP+A in combination with epirubicin (part 2). The primary endpoint was pathological complete response (pCR; ypT0/Tis ypN0) in the overall study population. A pCR rate of ≥ 40% was considered as a positive trial result. Overall, 58 pts were randomized to TP-A (n=29) or TP (n=29) in 9 Austrian study centers. Median age was 57 (range 33-82), 16 pts (27.6%) had hormone-receptor (HR)-negative and 42 (72.4%) had HR-positive tumors. 45 pts (77.6%) had stage ≤ IIA and 13 (22.4%) ≥ IIB. In 35 pts a pCR was observed (60.3%; 95%CI 47.5% - 71.9%), 19 (65.5%) in the TP-A group and 16 (55.2%) in TP group (Δ 10.3%; 95%CI -14.7% - 35.4%). Residual cancer burden (RCB) class 0 or I was seen in 44 out of 55 pts (80%) with valid RCB assessment. Treatment emergent adverse events (AEs) grade ≥ 3 were reported in 17 pts (29.3%), 9 in TP-A group (31.0%) and 8 (27.6%) in TP group. No AEs of special interest (immune-related AEs, cardiac disorders grade ≥ 2, or infusion-related reactions) grade ≥ 3 were detected. Outcome according to PD-L1 expression status is currently analyzed and will also be presented at the meeting. For HER2-positive EBC, a neoadjuvant chemotherapy de-escalation immunotherapy regimen with trastuzumab, pertuzumab, atezolizumab and epirubicin is highly effective and safe and merits further investigation.

P64 Health-Related Quality of Life in HER2-Positive Early Breast Cancer Woman Using Trastuzumab: A Systematic Review and Meta-Analysis

This study explored the effects of early trastuzumab treatment on health-related quality of life (HRQoL), including pooled meta-analysis, in an effort to provide an integrated assessment of HRQoL for Her2-positive early breast cancer patients.

155P Artificial Intelligence (AI) - powered human epidermal growth factor receptor-2 (HER2) and tumor-infiltrating lymphocytes (TIL) analysis for HER2-positive early breast cancer patients treated with HER2-targeted neoadjuvant chemotherapy (NAC)

HER2 is an important predictive biomarker of HER2-targeted therapies for breast cancer. Reliable HER2 testing is essential for clinical practice, but immunohistochemistry (IHC) staining results are susceptible to considerable interobserver variations.

A randomized, double-blind, phase III, non-inferiority clinical trial comparing the efficacy and safety of TA4415V (a proposed Trastuzumab biosimilar) and Herceptin (Trastuzumab reference product) in HER2-positive early-stage breast Cancer patients

BackgroundThis study compared efficacy and safety of TA4415V, a trastuzumab biosimilar, with reference trastuzumab in patients with human epidermal growth factor receptor 2–positive (HER2-positive) early-stage breast cancer treated in the neoadjuvant setting in Iran.MethodsPatients were randomly assigned to receive neoadjuvant TA4415V or reference trastuzumab concurrently with docetaxel (TH phase) for 4 cycles after treatment with 4 cycles of doxorubicin and cyclophosphamide (AC phase). Chemotherapy was followed by surgery. The primary endpoint was the comparison of pathologic complete response (pCR) rate in the per-protocol population. Secondary endpoints included comparisons of overall response rate (ORR), breast-conserving surgery (BCS), safety, and immunogenicity.ResultsNinety-two participants were analyzed in the per-protocol population (TA4415V, n = 48; reference trastuzumab, n = 44). The pCR rates were 37.50% and 34.09% with TA4415V and reference drug, respectively. The 95% CI of the estimated treatment outcome difference (− 0·03 [95% CI − 0.23 to 0.16]) was within the non-inferiority margin. No statistically significant difference was observed between the groups for other efficacy variables in the ITT population: ORR (89.13% vs. 83.33%; p = 0.72) and BCS (20.37% vs. 12.96%; p = 0.42) in the TA4415V and reference drug group, respectively.At least one grade 3 or 4 adverse events occurred in 27 (50%) patients in the TA4415V group versus 29 (53.70%) in the reference trastuzumab group (p = 0.70). The decrease in left ventricular ejection fraction (LVEF), as an adverse event of special interest (AESI) for trastuzumab, was compared between treatment groups in TH phase. Results demonstrated an LVEF decrease in 7 (12.96%) and 9 (16.67%) patients in TA4415V and reference trastuzumab groups, respectively (p = 0.59). Anti-drug antibodies (ADA) were not detected in any samples of groups.ConclusionsNon-inferiority for efficacy was demonstrated between TA4415V and Herceptin based on the ratio of pCR rates in HER2-positive early breast cancer patients. In addition, ORR and BCS, as secondary endpoints, were not significantly different. Safety profile and immunogenicity were also comparable between the two groups.

PREDICT underestimates survival of patients with HER2-positive early-stage breast cancer

The prognostic performance of PREDICT in patients with HER2-positive early breast cancer (EBC) treated in the modern era with effective chemotherapy and anti-HER2 targeted therapies is unclear. Therefore, we investigated its prognostic performance using data extracted from ALTTO, a phase III trial evaluating adjuvant lapatinib ± trastuzumab vs. trastuzumab alone in patients with HER2-positive EBC. Our analysis included 2794 patients. After a median follow-up of 6.0 years (IQR, 5.8–6.7), 182 deaths were observed. Overall, PREDICT underestimated 5-year OS by 6.7% (95% CI, 5.8–7.6): observed 5-year OS was 94.7% vs. predicted 88.0%. The underestimation was consistent across all subgroups, including those according to the type of anti HER2-therapy. The highest absolute differences were observed for patients with hormone receptor negative-disease, nodal involvement, and large tumor size (13.0%, 15.8%, and 15.3%, respectively). AUC under the ROC curve was 73.7% (95% CI 69.7–77.8) in the overall population, ranging between 61.7% and 77.7% across the analyzed subgroups. In conclusion, our analysis showed that PREDICT highly underestimated OS in HER2-positive EBC. Hence, it should be used with caution to give prognostic estimation to HER2-positive EBC patients treated in the modern era with effective chemotherapy and anti-HER2 targeted therapies.

Abstract P1-14-05: The impact of erythropoietin administration concomitantly with adjuvant anti-HER2 treatment on the patients’ outcome: Sub-analysis of the ALTTO study

Abstract Background: The erythropoietin (EPO) receptor activation can stimulate tumor proliferation and may be implicated in resistance to anti-HER2 therapies. EPO administration can be used for the management of chemotherapy-induced anemia. We aim to assess if EPO intake during the adjuvant anti-HER2 treatment impacts the outcomes of HER2-positive early breast cancer (EBC) patients. Methods: For this post hoc analysis of the ALTTO trial (NCT00490139), we categorized two cohorts according to the use of EPO during adjuvant anti-HER2 treatment: i) at least one EPO dose (EPO-cohort) vs ii) no EPO (non-EPO-cohort). We compared their baseline characteristics to identify potential confounders. The primary endpoint disease-free-survival (DFS), and the secondary endpoint overall survival (OS) were compared between these two cohorts, with subgroup analysis according to menopausal status, tumor characteristics, and anti-HER2 treatment. Kaplan Meier method, log-rank test, and Cox regression model adjusted for confounders were performed for DFS and OS (removal criterion p&amp;lt;0.10). The frequency of cardiovascular and thromboembolic adverse events (AEs) of EPO interest was compared between both cohorts. Results: Out of the 8,381 patients recruited in the ALTTO trial, 123 (1.5%) received EPO concomitantly with adjuvant treatment, 59 in the single HER2 blockade (Lapatinib (L)-alone or Trastuzumab (T)-alone) and 64 in dual blockade (T→L or T+L) arms. The median age of EPO-cohort patients was 54 (range: 27-74) years, and 39% were premenopausal, while most had pathologic tumor size &amp;gt;2 cm (56.9%), positive nodal status (58.5%), positive hormone receptor (HR) status (61.8%), and poorly differentiated or undifferentiated histologic grade (64.2%). Baseline characteristics were similar in both cohorts, except for the timing of chemotherapy, for which 93.5% of patients from the EPO-cohort were enrolled in the concurrent designs (2/2B) vs 44.2% in the non-EPO-cohort (p&amp;lt;0.001). Median FU was 6.9 years, with 6,409 (76.5%) patients still on follow-up. For the entire ALTTO cohort, the estimated 3- and 7-year DFS were 88.3% (95% CI: 87.6% - 89.0%) and 80.1% (95% CI: 79.1% - 81.0%), respectively. No difference in DFS by EPO administration (Yes/No) was observed (log-rank p=0.70). The effect of EPO remained non-significant when controlled for the four stratification factors and all other characteristics (p=0.91). The effect of EPO administration on DFS was significant for the subgroup of premenopausal women (p=0.041), favoring the EPO-cohort, noting that this result is based on small event numbers. The interaction was found significant in Cox analysis (p=0.024), remaining significant after adjustment for important prognostic variables (p=0.032). For the entire ALTTO cohort, 758 (9.0%) deaths occurred, with 3-year OS estimate 95.7% (95% CI: 95.2% - 96.1%) and 7-year OS estimate 89.9% (89.2% - 90.6%). The OS results are consistent with those for DFS regarding the lack of a significant association with EPO and the significance (p&amp;lt;0.10) of menopausal status and EPO interaction. In the EPO-cohort (n=123), eight (6.5%) AEs of EPO interest were recorded, while from the non-EPO-cohort (n=8,147), 417 (5.1%) reported similar AEs. Three fatal and 25 life-threatening AEs of EPO interest were recorded in the non-EPO-cohort, and none in the EPO-cohort. Conclusion: EPO administration to patients receiving adjuvant anti-HER2 treatment for HER2-positive EBC was safe and not associated with a harmful impact on survival outcomes, however the sample size of patients who received EPO is rather small. These findings contrast with data suggesting poorer outcomes with EPO, therefore further investigation of tumour microenvironment is needed to better understand these results, particularly in the premenopausal subgroup. Citation Format: Diogo Martins-Branco, Marie Kassapian, Véronique Debien, Rafael Caparica, Daniel Eiger, Urania Dafni, Charitini Andriakopoulou, Sarra El-Abed, Miguel Izquierdo, Malou Vicente, Saranya Chumsri, Martine Piccart-Gebhart, Alvaro Moreno-Aspitia, Ann Søegaard Knop, Janine Lombard, Evandro de Azambuja. The impact of erythropoietin administration concomitantly with adjuvant anti-HER2 treatment on the patients’ outcome: Sub-analysis of the ALTTO study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-14-05.

Response-Guided Omission of Anthracycline in Patients with HER2-Positive Early Breast Cancer Treated with Neoadjuvant Taxane and Trastuzumab: 5-Year Follow-Up of Prognostic Study Using Propensity Score Matching

Background: De-escalation therapy omitting anthracycline has been generally adopted for patients with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer in the adjuvant setting, but not in the neoadjuvant chemotherapy (NAC) setting. We investigated whether anthracycline can be omitted in HER2-positive early breast cancer patients receiving neoadjuvant taxane plus trastuzumab with clinical response. Methods: HER2-positive primary breast cancer patients treated using NAC containing trastuzumab were enrolled between September 2006 and July 2018 at Osaka Breast Clinic. The primary outcome was disease-free survival (DFS). The secondary outcome was overall survival (OS). We investigated survival with or without fluorouracil, epirubicin, and cyclophosphamide (FEC) using the log-rank test and propensity score matching (PSM). Results: In total, 142 patients were retrospectively included and median follow-up was 61 months. There was no significant difference in DFS (p = 0.93) and OS (p = 0.46) between the FEC-omitted group and the FEC-added group. The 5-year DFS was 91% and 88% and OS was 100% and 100%, respectively. After PSM, the FEC-omitted group and the FEC-added group had no significant differences in DFS (p = 0.459) and there were no death events in either group. The 5-year DFS was 90% and 88% and OS was 100% and 100%, respectively. Conclusions: Using PSM, the 5-year DFS of HER2-positive early breast cancer was not different with or without anthracycline. Response-guided omission of anthracycline may be an option for HER2-positive early breast cancer patients receiving neoadjuvant taxane and trastuzumab with good response in order to avoid overtreatment.

Perioperative HER2 targeted treatment in early stage HER2-positive breast cancer.

Although human epidermal growth factor receptor 2 (HER2)-positive breast cancer was associated with poor prognosis, it has been changed after the development of trastuzumab. There has been great progress in perioperative HER2-targeting treatment, and investigations of several novel drugs and their combinations are ongoing. Adjuvant trastuzumab with or without pertuzumab for 1 year in combination with concomitant chemotherapy has become a standard treatment in high-risk node-negative tumors or node-positive HER2-positive early breast cancer patients without residual disease or who have not received neoadjuvant treatment. For low-risk HER2-positive early breast cancer patients, adjuvant paclitaxel and 1-year trastuzumab are possible alternatives. For residual disease after neoadjuvant treatment, adjuvant trastuzumab emtansine (T-DM1) for 14 cycles is a standard treatment. Non-anthracycline chemotherapy with dual anti-HER2 targeting of trastuzumab and pertuzumab represents one of the preferred neoadjuvant regimens to achieve higher pathologic complete response (pCR) rates and better clinical outcomes. Further research is needed to develop and validate potential biomarkers to predict pCR, which could help escalate or de-escalate anti-HER2 therapy. Trials incorporating novel agents such as T-DM1, trastuzumab deruxtecan (T-DXd), and immune checkpoint inhibitors and trying to de-escalate treatments in neoadjuvant setting are ongoing. In the future, tailored treatments such as no adjuvant therapy, various HER2-directed therapies alone with chemotherapy, combinations of various HER2-directed therapies and chemotherapy, addition of immune checkpoint inhibitors, and omission of surgery will be individualized in HER2-positive early breast cancer patients.

Pathologic complete response to neoadjuvant anti-HER2 therapy is associated with HER2 immunohistochemistry score in HER2-positive early breast cancer.

To evaluate whether pathologic complete response (pCR) to neoadjuvant anti-human epidermal growth factor receptor 2 (HER2) therapy is dependent on the HER2 immunohistochemistry (IHC) score.A total of 181 HER2-positive early breast cancer patients who had received neoadjuvant anti-HER2 therapy were included in this study. Associations were examined between IHC score and tumor pCR status (commonly defined by ypT0+ypN0, ypT0/is+ypN0, or ypT0/is).In trastuzumab-based neoadjuvant-treated patients, ypT0+ypN0 was achieved in 46.0% of patients with HER2 IHC 3+ tumors but only 25.0% of patients with HER2 IHC 2+/fluorescence in situ hybridization (FISH)-positive tumors (P = .016). When pCR was defined as ypT0/is+ypN0 or ypT0/is, 54.7% and 61.3% of patients with HER2 IHC 3+ tumors had a pCR, whereas only 29.5% and 38.6% with HER2 IHC 2+/FISH-positive tumors achieved pCR (P = .004 and P = .008, respectively). The association between dual HER2 blockade and pCR was almost exclusively confined to HER2 IHC 3+ tumors (ypT0+ypN0: 61.9% vs 38.9%, P = .013; ypT0/is+ypN0: 71.4% vs 47.4%, P = .009; and ypT0/is: 81.0% vs 52.6%, P = .002) and was absent in HER2 IHC 2+/FISH-positive tumors. Multivariate logistic regression revealed that HER2 IHC 3+ tumors had a significantly higher probability of achieving ypT0+ypN0 (odds ratio [OR], 0.265; 95% confidence interval [CI], 0.109–0.645; P = .003), ypT0/is+ypN0 (OR, 0.221; 95% CI, 0.094–0.521; P = .001), and ypT0/is (OR, 0.254; 95% CI, 0.111–0.583; P = .001) than HER2 IHC 2+/FISH-positive tumors. A significantly better pCR rate was also found in patients with T1 tumors and patients with dual HER2 blockade.The pCR rate was highly correlated with the HER2 IHC score in neoadjuvant anti-HER2 treatment. The addition of pertuzumab to a neoadjuvant trastuzumab-based regimen improved pCR rates, but there was no significant difference in pCR rates in the IHC 2+/FISH-positive group. This suggests that HER2 IHC scores can predict the effectiveness of treatment.

Preoperative Systemic Therapy Versus Upfront Surgery in HER2-Positive Breast Cancer in the Real World.

PurposeTo compare survival in different strategies, preoperative systemic treatment versus upfront surgery, in HER2-positive early breast cancer patients in the real world.MethodsAccording to the actual upfront treatment, eligible patients from 2012 to 2015 were classified as preoperative systemic treatment or upfront surgery group prospectively. The primary endpoint is disease-free survival; the second endpoint is overall survival. All the outcomes were examined in the propensity score matching model and inverse probability of treatment weighting model.ResultsIncluded in the analysis were 1,067 patients (215 in the preoperative systemic treatment group, 852 in the upfront surgery group). In the propensity score matching model (matching at 1:1 ratio), the disease-free survival of the preoperative systemic treatment group was significantly higher than that of the upfront surgery group (hazard ratio, 0.572, 95%CI, 0.371–0.881, P, 0.012). In the inverse probability of treatment weighting model, there was no significant difference in disease-free survival between the two groups (hazard ratio, 0.946, 95%CI, 0.763–1.172, P, 0.609). For overall survival, there was no significant difference between the two groups.ConclusionThe HER2-positive patients who accepted preoperative systemic treatment had better disease-free survival than those who underwent upfront surgery by real-world statistic methods.Clinical Trial RegistrationClinicaltrials.gov, identifier NCT04249440.

Potential non-drug cost differences associated with the use of the fixed-dose combination of pertuzumab and trastuzumab for subcutaneous injection (PH FDC SC) in the treatment of HER2-positive early breast cancer patients in Western Europe and the United States.

544 Background: In patients with HER2-positive early breast cancer (BC), pertuzumab (P) added to trastuzumab (T) and chemotherapy has been recognized as a standard-of-care, improving the risk of recurrence. P and T treatments can be given intravenously (PT IV) or, more recently, subcutaneously − via PH FDC SC. Both methods are comparable in terms of efficacy and safety profiles. However, PH FDC SC allows for a faster infusion than that of PT IV, and this can be associated with lower costs. The aim of this study is to estimate the incremental difference in non-drug costs between PH FDC SC and PT IV for a typical patient receiving treatment for HER2-positive early BC in Western Europe and the United States. Methods: A model-based cost-minimization analysis was performed to quantify mean non-drug cost differences per patient over a full course of therapy (18 cycles). Western Europe: costs in the analysis are based on an archetypal country, and explicitly include estimates for costs for patient chair time, active healthcare professional (HCP) time, usage of non-drug consumables, port-a-cath placement surgeries and patients’ productivity losses. Costs are calculated by multiplying the resource use by its corresponding unit price. Costing data were obtained from literature sources on T SC time and cost savings for Western European countries, and assumptions on PH FDC SC and PT IV times and costs. United States: non-drug costs for the two strategies were estimated using average net reimbursement amounts for relevant procedure codes for intravenous and SC therapy administration among commercial payers in the MarketScan databases. Results: PH FDC SC is estimated to reduce non-drug costs by 73% − 80% in Western Europe, and 75% in the United States. Total monetary non-drug savings per patient over 18 cycles of treatment are estimated in the range of €2,474 − €8,975 in Western Europe, and at $10,138 in the United States. In Western Europe, where the analysis allows for a disaggregation by cost category, cost savings related to savings in patient chair time (excluding patients’ productivity losses) are estimated to account for up to 62% of overall non-drug cost savings. Patients’ productivity losses are estimated to explain up to 11% of non-drug cost differences. Conclusions: The use of PH FDC SC for the treatment of HER2-positive BC can potentially result in substantial non-drug cost savings. These savings could easily derive in overall net cost savings to the healthcare system, contributing to the long-term sustainability of the healthcare spending, while still providing a safe and effective therapy.[Table: see text]

52P Adjuvant endocrine therapy in HER2-positive breast cancer patients: Systematic review and meta-analysis

Approximately 50% of HER2-positive breast cancer lesions express hormone receptors. These tumors present a unique therapeutic challenge, and the optimal endocrine therapeutic approach remains controversial. We aimed to study the optimal adjuvant endocrine therapy in this setting in order to better establish the bases for clinical recommendations in HER2-positive disease. We conducted a literature search up to May 2020 in which we identified randomized controlled trials (RCTs) that investigated the efficacy of various adjuvant hormonal therapies among premenopausal and postmenopausal patients with hormone receptor (HR)-positive HER2-positive early breast cancer. Disease-free survival (DFS) was calculated with the random effect model and hazard ratios (HRs) with 95% confidence intervals (CI). Six RCTs (n=5,390 patients) were included in the final analysis. There was no significant difference in DFS between adjuvant treatment with aromatase inhibitors and tamoxifen (HR 0.99, 95% CI 0.68-1.44, P=0.96). After omitting the ALTTO trial because it did not randomize patients to hormonal therapy, no significant difference was observed between the two protocols (HR 1.06, 95% CI 0.65-1.73, P=0.81). Our study demonstrates similar DFS with tamoxifen and aromatase inhibitors as adjuvant endocrine treatment in HER2-positive HR-positive early breast cancer patients. Future larger prospective studies focusing on the various contemporary endocrine regimens are warranted to validate our findings.