Neoadjuvant anti-HER2 Therapy Research Articles

GDF-15 is a potential candidate biomarker for an elevated risk of cardiotoxicity in breast cancer patients receiving neoadjuvant dual anti-HER2 therapy

ObjectiveGrowth differentiation factor 15 (GDF-15) is a stress-responsive cytokine that regulates myocardial injury, cardiac overloading pressure, and inflammation and is related to the risk of cardiovascular diseases and events. The current study aimed to investigate the correlation of GDF-15 levels with clinical features, biochemical indices, and especially the risk of cardiotoxicity in breast cancer patients receiving neoadjuvant dual anti-HER2 therapy.MethodsA total of 103 HER2-positive breast cancer patients who underwent neoadjuvant dual anti-HER2 therapy (trastuzumab and pertuzumab plus chemotherapy) were included. Serum GDF-15 levels before neoadjuvant treatment were detected by enzyme-linked immunosorbent assay. Cardiotoxicity was evaluated during neoadjuvant therapy by referring to a decline of ≥10 percentage points in the left ventricular ejection fraction from baseline to an absolute level less than 50%.ResultsGDF-15 exhibited a skewed distribution, with a median level of 714 (range: 207–1805) pg/mL. GDF-15 was positively correlated with age (p = 0.037), diabetes (p = 0.036), and the N-terminal pro-brain natriuretic peptide level (p = 0.013) and positively correlated with the total cholesterol level (p = 0.086) and troponin T level (p = 0.082), but these correlations were not statistically significant. A total of 6.8% of patients experienced cardiotoxicity during neoadjuvant therapy. By comparison, the GDF-15 level was greater in patients who experienced cardiotoxicity than in those who did not (p = 0.008). A subsequent receiver operating characteristic curve revealed that GDF-15 predicted cardiotoxicity risk, with an area under the curve of 0.803 (95% CI: 0.664–0.939). After multivariate adjustment, GDF-15 independently predicted a greater risk of cardiotoxicity (p = 0.020).ConclusionGDF-15 is a candidate biomarker for increased risk of cardiotoxicity in breast cancer patients receiving neoadjuvant dual anti-HER2 therapy.

Abstract PO5-01-04: HER2 Amplification Level and Focal/Broad Region Size as Predictors of Treatment Response in Neoadjuvant Chemotherapy and Anti-HER2 Therapy for HER2-Positive Breast Cancer

Abstract Background: Neoadjuvant chemotherapy combined with anti-HER2 therapy has become the standard treatment approach for HER2-positive breast cancer. However, not all HER2-positive patients can achieve pathological complete response after neoadjuvant therapy. This raises the question of which subset of HER2+ patients derive the greatest benefit from pre-operative HER2-targeted treatment. Therefore, this study aims to determine whether the level and amplification region size of HER2 amplification are associated with the efficacy of neoadjuvant chemotherapy combined with anti-HER2 therapy. Methods: A total of 523 breast cancer samples were collected from 2017 to 2018, among which 202 cases were HER2-positive patients. Among these, 55 HER2-positive patients received neoadjuvant chemotherapy combined with anti-HER2 targeted therapy. The amplification status of HER2 was assessed using immunohistochemistry/fluorescence in situ hybridization (IHC/FISH) and next-generation sequencing (NGS). The HER2/CEP17 ratio, determined by FISH, was used to represent the amplification level of HER2. The size of the amplification region was calculated using NGS and neighboring genes located in chr17q. Amplification regions smaller than 1 Mb were classified as focal amplification, while those larger than 1 Mb were classified as broad amplification. Results: We compared the HER2/ERBB2 status of 523 breast cancer patients using different detection methods and found a high concordance between ERBB2 amplification detected by NGS and HER2-positivity detected by IHC and FISH, with a sensitivity of 96.0%, specificity of 97.8%, and overall concordance of 97.1%. Based on the HER2/CEP17 ratio determined by FISH, we observed that using a threshold of 6 for classification, the high amplification group had a significantly higher pCR rate compared to the low amplification group (86.7% vs. 41.7%; p=0.037, odds ratio [OR]=0.121, 95% confidence interval [CI]: 0.009-0.919). Moreover, the focal amplification group showed a higher pCR rate compared to the broad amplification group (65.9% vs. 30.8%, p=0.051, OR=0.237, 95% CI: 0.045-1.035). Additionally, within the low amplification group (HER2/CEP17 < 6), the pCR rate was 66.7% for focal amplification and 20% for broad amplification, suggesting that focal amplification of ERBB2 may further guide clinical benefit in the low HER2/CEP17 ratio group. Conclusion: This study demonstrates a high concordance between ERBB2 amplification determined by NGS and HER2-positivity determined by IHC/FISH. High HER2/CEP17 ratio and focal amplification of ERBB2 are associated with a higher pCR rate in neoadjuvant chemotherapy combined with anti-HER2 targeted therapy. Citation Format: Ning Liao, Guochun Zhang, Xinze Lv, Kai Li, Ting Hou, Zhou Zhang. HER2 Amplification Level and Focal/Broad Region Size as Predictors of Treatment Response in Neoadjuvant Chemotherapy and Anti-HER2 Therapy for HER2-Positive Breast Cancer [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 PO5-01-04.

Abstract PO1-27-06: HER2 Amplification Level and Focal/Broad Region Size as Predictors of Treatment Response in Neoadjuvant Chemotherapy and Anti-HER2 Therapy for HER2-Positive Breast Cancer

Abstract Background: Neoadjuvant chemotherapy combined with anti-HER2 therapy has become the standard treatment approach for HER2-positive breast cancer. However, not all HER2-positive patients can achieve pathological complete response after neoadjuvant therapy. This raises the question of which subset of HER2+ patients derive the greatest benefit from pre-operative HER2-targeted treatment. Therefore, this study aims to determine whether the level and amplification region size of HER2 amplification are associated with the efficacy of neoadjuvant chemotherapy combined with anti-HER2 therapy. Methods: A total of 523 breast cancer samples were collected from 2017 to 2018, among which 202 cases were HER2-positive patients. Among these, 55 HER2-positive patients received neoadjuvant chemotherapy combined with anti-HER2 targeted therapy. The amplification status of HER2 was assessed using immunohistochemistry/fluorescence in situ hybridization (IHC/FISH) and next-generation sequencing (NGS). The HER2/CEP17 ratio, determined by FISH, was used to represent the amplification level of HER2. The size of the amplification region was calculated using NGS and neighboring genes located in chr17q. Amplification regions smaller than 1 Mb were classified as focal amplification, while those larger than 1 Mb were classified as broad amplification.> Results: We compared the HER2/ERBB2 status of 523 breast cancer patients using different detection methods and found a high concordance between ERBB2 amplification detected by NGS and HER2-positivity detected by IHC and FISH, with a sensitivity of 96.0%, specificity of 97.8%, and overall concordance of 97.1%. Based on the HER2/CEP17 ratio determined by FISH, we observed that using a threshold of 6 for classification, the high amplification group had a significantly higher pCR rate compared to the low amplification group (86.7% vs. 41.7%; p=0.037, odds ratio [OR]=0.121, 95% confidence interval [CI]: 0.009-0.919). Moreover, the focal amplification group showed a higher pCR rate compared to the broad amplification group (65.9% vs. 30.8%, p=0.051, OR=0.237, 95% CI: 0.045-1.035). Additionally, within the low amplification group (HER2/CEP17 < 6), the pCR rate was 66.7% for focal amplification and 20% for broad amplification, suggesting that focal amplification of ERBB2 may further guide clinical benefit in the low HER2/CEP17 ratio group. Conclusion: This study demonstrates a high concordance between ERBB2 amplification determined by NGS and HER2-positivity determined by IHC/FISH. High HER2/CEP17 ratio and focal amplification of ERBB2 are associated with a higher pCR rate in neoadjuvant chemotherapy combined with anti-HER2 targeted therapy. Citation Format: Ning Liao, Guochun Zhang, Xinze Lv, Kai Li, Ting Hou, Zhou Zhang. HER2 Amplification Level and Focal/Broad Region Size as Predictors of Treatment Response in Neoadjuvant Chemotherapy and Anti-HER2 Therapy for HER2-Positive Breast Cancer [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 PO1-27-06.

Abstract PO3-19-05: Phase III study to evaluate the efficacy and safety of GLSI-100 (GP2 + GM-CSF) in breast cancer patients with residual disease or high-risk PCR after both neo-adjuvant and postoperative adjuvant anti-HER2 therapy, Flamingo-01

Abstract Background: GP2 is a biologic nine amino acid peptide of the HER2/neu protein delivered in combination with Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) that stimulates an immune response targeting HER2/neu expressing cancers, the combination known as GLSI-100. In a prospective, randomized, single-blinded, placebo-controlled, multicenter Phase IIb study, no recurrences were observed in the HER2+ population after 5 years of follow-up, if the patient was treated with GLSI-100, survived, and was followed for more than 6 months (p = 0.0338). Immunotherapy elicited a potent response measured by skin tests and immunological assays. Of the 146 patients that have been treated with GLSI-100 over 4 clinical trials, GLSI-100 was well-tolerated and no serious adverse events observed were considered related to the immunotherapy. Methods: This Phase III trial is a prospective, randomized, double-blinded, multi-center study. After 1 year of trastuzumab-based therapy, 6 intradermal injections of GLSI-100 or placebo will be administered over the first 6 months and 5 subsequent boosters will be administered over the next 2.5 years for a total of 11 injections over 3 years. The participant duration of the trial will be 3 years treatment plus 1 additional year follow-up for a total of 4 years following the first year of treatment with trastuzumab-based therapy. Patients will be stratified based on residual disease status at surgery, hormone receptor status and region. Study Size – Interim Analysis: Approximately 498 patients will be enrolled. To detect a hazard ratio of 0.3 in invasive breast cancer free survival (IBCFS), 28 events will be required. An interim analysis for superiority and futility will be conducted when at least 14 events have occurred. This sample size provides 80% power if the annual rate of events in placebo patients is 2.4% or greater. Up to 100 non-HLA-A*02 subjects will be enrolled in an open-label arm. Eligibility Criteria: The patient population is defined by these key eligibility criteria: Objectives: Study Status: The study has been initiated at a number of sites in the US. The study is also expected to be opened in Spain, Germany, and France. Contact Information: Greenwich LifeSciences, Inc. Stafford, TX Email: Flamingo-01@greenwichlifesciences.com Website: greenwichlifesciences.com Funding: This trial is supported by Greenwich LifeSciences. Citation Format: Snehal Patel, Jaye Thompson, Mira Patel, F. Joseph Daugherty, Mothaffar Rimawi. Phase III study to evaluate the efficacy and safety of GLSI-100 (GP2 + GM-CSF) in breast cancer patients with residual disease or high-risk PCR after both neo-adjuvant and postoperative adjuvant anti-HER2 therapy, Flamingo-01 [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 PO3-19-05.

Abstract PO5-25-11: Appropriate use of interventional cohort studies with threshold-crossing designs for de-escalation trials in breast cancer

Abstract For some populations of patients with early breast cancer (BC), clinical outcomes have improved such that the focus has shifted to identifying aspects of therapy that can be reduced or omitted to spare patients toxicity without compromising outcomes. For example, in patients with HER2+ disease, introduction of HER2-targetted therapy significantly reduced event rates but at increased exposure to toxicity. For those with a pathological complete response (pCR) to neo-adjuvant anti-HER2 therapy, the absolute gain from continued adjuvant therapy is likely to be small and the event rate sufficiently low such that any deviation from the expected prognosis would be sufficient to infer failure of a reduced treatment strategy. Previous studies would usually adopt a non-inferiority (NI) trial randomising patients between standard of care (SOC) and reduced therapy. The reduced therapy would be declared non-inferior if the difference between the groups does not exceed a pre-agreed NI margin. Some populations, such as those described, have a very low rate of recurrence and thus large sample sizes are required to gain sufficient power resulting in several issues. In these situations, threshold-crossing designs, also known as interventional cohort studies (ICS), provide an alternative to traditional NI trials. In ICS, a single cohort is recruited and receives the reduced therapy. The event rate is compared to a pre-defined fixed threshold, above which recurrence rates would be considered unacceptable. When conducted appropriately, such studies are statistically and logistically efficient, and should be considered definitive. ICS can be used when 1. A stable background of SOC exists with robust data from which an appropriate crossing-boundary can be defined. Critically, the historical control population used to define the boundary must closely reflect the study population and those seen in clinical practice. 2. The event rate is sufficiently low and consequently has low variability, so a concurrent control group is not required because an accurate estimate of the event rate with SOC already exists. 3. The primary endpoint of interest is reliable, sensitive to treatment and timely to allow early stopping if interim analyses indicate an issue. The well-defined excellent prognosis of patients with HER2+ BC who have a pCR to contemporary neo-adjuvant therapy, coupled with the pattern of relapse rates dropping off rapidly after 3 years, makes this an appropriate setting for implementing such designs. Three recently initiated studies testing reduced therapy in this patient population, HER2-RADiCAL (NIHR131362), CompassHER2 (NCT04266249) and DECRESCENDO (NCT04675827), all have an ICS design. An ICS approach is also valid for trials testing avoidance of radiotherapy in very low-risk populations, where the absolute benefit is likely low and occurrence of late local events is salvageable so as not to impact on overall survival, such as in PRIMETIME (ISRCTN 41579286). In contrast, there are several settings where these designs should not be used. For example, in the assessment of systemic therapy in ER+ HER2- BC the recurrence rate is constant beyond 3 years meaning events cannot be picked up in a timely manner and a fixed threshold defined at 3/5 years would not allow preclusion of a later drop-off in efficacy. It would also be premature to use ICS in TNBC following immunotherapy as outcome data is not yet sufficiently mature to accurately define a suitable threshold. Finally, if relapse rates are not sufficiently low, natural variation in control group incidence rates would prevent setting a suitable fixed threshold. We will discuss the key requirements and design features for using ICS to efficiently evaluate avoidance of treatment in BC and highlight the importance of patient involvement in the development of such trials. Citation Format: Holly Tovey, Laura Finneran, Lucy Kilburn, Iain Macpherson, Andrew Wardley, Hilary Stobart, Lesley Turner, Mairead MacKenzie, Charlotte Coles, Cliona Kirwan, Judith Bliss. Appropriate use of interventional cohort studies with threshold-crossing designs for de-escalation trials in breast cancer [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 PO5-25-11.

Neoadjuvant pertuzumab plus trastuzumab in combination with chemotherapy for human epidermal growth factor receptor 2 positive breast cancer: a real-world retrospective single-institutional study in China

IntroductionReal-world studies on neoadjuvant dual anti-HER2 therapy combined with chemotherapy for breast cancer (BC) are scarce in China. This study aimed to evaluate the efficacy and safety of neoadjuvant dual anti-HER2 therapy combined with chemotherapy in a real-world setting. Moreover, differences in estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and proliferation cell nuclear antigen (Ki-67) expression pre- and post-neoadjuvant therapy were analyzed.MethodsClinical and pathological data of patients with HER2-positive BC who received neoadjuvant dual anti-HER2 therapy combined with chemotherapy at Liaoning Cancer Hospital & Institute, China, between September 2021 and September 2023, were retrospectively reviewed.ResultsAmong 179 included patients, a pathologic complete response (pCR) was achieved in 109 patients (60.9%). The univariate analysis results indicated that the hormone receptor (HR) status (P = 0.013), HER2 status (P = 0.003), and cycles of targeted treatment (P = 0.035) were significantly correlated with pCR. Subsequent multivariable analysis showed that HR negative and HER2 status 3 + were independent predictive factors of pCR. Anemia was the most common adverse event (62.0%), and the most common grade 3–4 adverse event was neutropenia (6.1%). The differences in HER2 (34.5%) and Ki-67 (92.7%) expression between core needle biopsy and the residual tumor after neoadjuvant therapy were statistically significant, whereas the differences were insignificant in terms of ER or PR status.ConclusionsThe combination of neoadjuvant trastuzumab and pertuzumab with chemotherapy showed good efficiency, and the toxic side effects were tolerable in patients with BC. In cases where pCR was not achieved after neoadjuvant therapy, downregulation of HER2 and Ki-67 expressions was observed.

353TiP Phase III study to evaluate the efficacy and safety of GLSI-100 (GP2 + GM-CSF) in breast cancer patients with residual disease or high-risk PCR after both neo-adjuvant and postoperative adjuvant anti-HER2 therapy, Flamingo-01

353TiP Phase III study to evaluate the efficacy and safety of GLSI-100 (GP2 + GM-CSF) in breast cancer patients with residual disease or high-risk PCR after both neo-adjuvant and postoperative adjuvant anti-HER2 therapy, Flamingo-01

P11.54.A BRAIN RELAPSE IN HER2-POSITIVE BREAST CANCER AFTER NEOADJUVANT TREATMENT: AN INTERNATIONAL MULTICENTRIC STUDY

Abstract BACKGROUND The incidence of central nervous system relapse among patients with breast cancer appears to be increasing, despite advances in systemic treatment. Although achieving pathological complete response (pCR) following neoadjuvant treatment has been associated with improved survival outcomes, it does not seem to prevent brain relapse. In early stage HER 2 positive disease between 10-14% will develop brain metastases and the risk is higher in endocrine receptor-negative setting. Identifying patients who are at greater risk of brain relapse can help to indicate those who need new treatment options to prevent it. This study aimed to assess the incidence of brain relapse in a multicenter cohort of patients who underwent neoadjuvant treatment across nine hospitals located in Portugal, Spain, and Chile, and to identify factors associated with it. MATERIAL AND METHODS We conducted a retrospective analysis of patients diagnosed and treated for HER2-positive breast cancer in nine hospitals located in Portugal, Spain, and Chile between January 2017 and December 2022. To be eligible for inclusion, patients must have undergone neoadjuvant anti-HER2 therapy followed by surgery. Data such as age at diagnosis, endocrine receptor expression, chemotherapy regimen, pathological response, adjuvant anti-HER2 treatment, endocrine therapy, and first local of relapse were analysed. RESULTS A total of 396 patients with a mean age of 52.9 years were included in the study. All patients received a neoadjuvant chemotherapy regimen and double anti-HER2 therapy with trastuzumab and pertuzumab, with a pathological complete response (pCR) achieved in 59.6% of patients. Nearly all patients (98.2%) received adjuvant anti-HER2 therapy, with 83.81% receiving trastuzumab, 12.85% receiving TDM1, and 3.34% receiving trastuzumab plus pertuzumab. Over a follow-up period of 3.5 years, 23 patients (5.81%) experienced relapse. Among these cases, 10 patients (2.5%) had brain relapse as first site, accounting for 43.48% of the total recurrences. Brain relapse was not associated with pathological response, but rather with a more advanced stage at diagnosis (T3/4 or Nodal positive) (p<0.05). CONCLUSION In CONCLUSION , our multicentric cohort study provides valuable insights into the incidence and factors associated with brain metastasis in HER2-positive breast cancer patients who underwent neoadjuvant treatment. Our findings suggest that although neoadjuvant treatment resulted in a high rate of pCR, it did not prevent brain relapse. Importantly, our study identified advanced disease stage at diagnosis as a significant risk factor for brain relapse. Further studies are needed to identify additional factors associated with brain metastasis and explore potential preventive strategies in patients with higher risk.

Association of PIK3CA mutation with outcomes in HER2-positive breast cancer treated with anti-HER2 therapy: A meta-analysis and bioinformatic analysis of TCGA‑BRCA data

BackgroundThis study aimed to comprehensively explore the clinical significance of PIK3CA mutation in human epidermal growth factor receptor 2 (HER2)-positive breast cancer treated with anti-HER2 therapy. MethodsWe systematically searched PubMed, Embase, and the Cochrane databases for eligible studies assessing the association between PIK3CA mutation and outcomes in patients with HER2-positive breast cancer receiving anti-HER2 therapy. The main outcomes included: (1) pathological complete response (pCR) or disease-free survival (DFS) for the neoadjuvant setting; (2) DFS or invasive DFS for the adjuvant setting; (3) objective response rate (ORR), progression-free survival (PFS), time-to-progression (TTP), or overall survival (OS) for the metastatic setting. The mutational landscape of HER2-positive breast cancer according to PIK3CA mutation status was examined based on TCGA breast cancer dataset. ResultsTotally, 43 eligible studies, covering 11,099 patients with available data on PIK3CA mutation status, were identified. In the neoadjuvant setting, PIK3CA mutation was significantly associated with a lower pCR rate (OR=0.23, 95% CI 0.19–0.27, p<0.001). This association remained significant irrespective of the type of anti-HER2 therapy (single-agent or dual-agent) and hormone receptor status. There were no significant differences in DFS between PIK3CA mutated and wild-type patients in either the neoadjuvant or adjuvant settings. In the metastatic setting, PIK3CA mutation predicted worse ORR (OR=0.26, 95%CI 0.17–0.40, p<0.001), PFS (HR=1.28, 95%CI 1.03–1.59, p = 0.024) and TTP (HR=2.27, 95%CI 1.54–3.34, p<0.001). However, no significant association was observed between PIK3CA mutation status and OS. Distinct mutational landscapes were observed in HER2-positive breast cancer between individuals with PIK3CA mutations and those with wild-type PIK3CA. ConclusionsPIK3CA mutation was significantly associated with a lower pCR rate in HER2-positive breast cancer treated with neoadjuvant anti-HER2 therapy. In the metastatic setting, PIK3CA mutation was predictive of worse ORR, PFS and TTP. These results suggest the potential for developing PI3K inhibitors as a therapeutic option for these patients.

Invasive Breast Cancer with HER2 ≥4.0 and

To investigate the HER2 status and clinicopathological features in invasive breast cancer with HER2 ≥4.0 and <6.0, which has always been controversial. Forty breast cancer cases with HER2 ≥4.0 and <6.0 by fluorescence in situ hybridization (FISH) were collected and classified into two groups based on the HRE2/CEP17 ratio (Group A: ≥2.0, n=22; Group B: <2.0, n=18). Clinicopathological characteristics, HER2 status, risk classification, and molecular typing were further analyzed and compared by 21-Gene expression assay and MammaPrint plus BluePrint test. The majority of cases in both groups were invasive carcinoma (NOS), with histological grade II, HR+, Ki-67 ≥20%, HER2 2+, and a high risk of recurrence, although younger patients and lymph node metastases were more common in Group A. Surprisingly, all HR+ breast cancers in both groups were classified as luminal-type, HR- cases were all basal-type or unknown, and the index of HER2 in all cases was <0.000 using the BluePrint test, which indicated that HER2 status should be negative. Furthermore, the level of HER2 mRNA expression in all cases of both groups was <10.7, which was defined as HER2 negative by the 21-Gene expression assay. In addition, 10 patients of Group A received anti-HER2 neoadjuvant therapy; only one patient with HR- achieved Grade 5 based on the Miller-Payne system, whereas none of the patients achieved pathological complete response (pCR) based on the Residual Cancer Burden system. Group A breast cancer, which has always been unquestionably diagnosed as HER2 amplification, was more likely to be HER2 negative and derived less benefit from anti-HER2 neoadjuvant chemotherapy. Group A breast cancer should be distinguished from classical HER2-positive breast cancers when assessing HER2 FISH, and a larger cohort of Group A patients should be included in further studies.

Role of plasma circulating HER2/EFTUD2 ratio in predicting pathological complete response (pCR) after neoadjuvant dual anti-HER2 therapy in HER2-positive breast cancer (HER2+ BC).

e12592 Background: Achieving pCR following neoadjuvant chemo and anti-HER2 therapy is associated with a significantly better survival in HER2+ BC. There is currently a lack of a robust biomarker to predict pCR in HER2+ BC. Using EFTUD2 as chromosome 17 reference probe, circulating HER2/EFTUD2 plasma DNA copy number ratio (H-ratio) detected by droplet digital PCR (ddPCR) was shown to have high concordance with the tumor HER2 status. We aim to evaluate whether the change in H-ratio is associated with response to neoadjuvant dual anti-HER2 therapy. Methods: We prospectively recruited patients with HER2+ BC who received neoadjuvant taxane, trastuzumab and pertuzumab followed by radical surgery from May 2019 to April 2022. Serial plasma samples (n = 49) were collected at pre-treatment (Tpre), at 4th cycle (Tmid) and at completion of neoadjuvant treatment (Tpost). H-ratio was determined in each plasma sample using droplet ddPCR (QX200 ddPCR system, Bio-rad). H-ratio responders were defined as patients having a declining Tpost H-ratio, whereas patients having a rising or persistent Tpost H-ratio were defined as H-ratio non-responders. The relationship between pCR, H-ratio and various clinicopathological characteristics were evaluated by Spearman’s correlation, Fisher’s exact test and Wilcoxon signed-rank test. Results: Eighteen clinical stage II or III HER2+ BC patients with a median age of 56 years old (range 33 - 71) were included. The median H-ratio at Tpre, Tmid and Tpost were 1.27, 1.12 and 1.10, respectively. Higher Tpre H-ratio was significantly associated with larger tumor size (p = 0.004) and higher tumor grade (G1-2 vs G3; median H-ratio 1.15 vs 1.78; p = 0.024). Six patients (33.3%) were H-ratio responders. Ten (55.6%) of 18 patients achieved pCR after completion of neoadjuvant treatment. The pCR rate in H-ratio responders was significantly higher than the H-ratio non-responders (100% vs. 36.4%; p = 0.017). In predicting pCR, H-ratio response outperformed hormonal receptor (HR) negativity (HR- vs HR+; 72.7% vs 28.6%; p = 0.088) or high tumor grade (G1-2 vs G3; 66.7% vs 33.3%; p = 0.201). There was no association between pCR and Tpre/Tmid/Tpost H-ratio. With a median follow up of 22.8 months (range 8.2 - 41.8), there were no relapse or death. Conclusions: A high pre-treatment plasma circulating HER2/EFTUD2 ratio is associated with large tumor size and high tumor grade in HER2+ BC. The decline of HER2/EFTUD2 ratio after neoadjuvant dual anti-HER2 therapy predicts pCR, and may serve as a potential biomarker for treatment de-escalation.

Characterization of patients with recurrent breast cancer submitted to neoadjuvant therapy in a Brazilian cancer center.

e13013 Background: Breast cancer patients submitted to neoadjuvant therapy have clinical-pathological factors that can correlate with favorable outcomes, such as pathologic complete response (pCR). However, patients who achieve pCR may develop recurrence due to other identifiable risk factors, and some molecular subtypes lack a prognostic marker such as pCR, depending on other factors to determine the risk of recurrence. Objective: Analyse clinical-pathological data from patients with recurrent breast cancer who received neoadjuvant therapy, and identify possible risk factors in this population. Methods: This is an observational, descriptive, retrospective study of patients with recurrent breast cancer, submitted to neoadjuvant therapy between January 2007 and December 2018, at the AC Camargo Cancer Center; São Paulo, Brazil. Of the 1145 patients treated with neoadjuvant therapy, we evaluated 304 who recurred, and crossed data with 841 patients that didn't present recurrence. Results: We analysed 304 patients (26.6%), 60.1% pre-menopause, 6.5% with BRCA1/2 gene mutation, 85.9% had invasive ductal carcinoma (IDC), 53.8% were histologic grade (HG) III, and 84.2% had KI67 &gt;20%. Clinical stage was 44.7% cT4, 28.3% cT3, 25.7% cT2 and 1.3% cT1, while 13.3% were cN3, 21.1% cN2, 43.8% cN1 and 21.7% cN0. Grouped clinical stage was 74.4% III, 25% II and 0.7% I. Molecular subtypes were 52.4% hormone receptor positive/HER2 negative (HR+/HER2-), 12.2% HR+/HER2+, 6.9% HR-/HER2+ and 28.6% HR-/HER2-. Regarding neoadjuvant chemotherapy, 92% received anthracycline and taxane, 23% dose-dense, 17.4% received trastuzumab with or without pertuzumab, and 20% of ER-/HER2- received carboplatin. Chemotherapy interruption occurred in 13.2% of patients, and 31.1% interrupted anti-HER2 therapy. Surgery was 82.9% mastectomy, 77% axillary dissection and 16.4% breast-conserving surgery. Residual Cancer Burden (RCB) score was 13.1% RCB 0, 5.8% RCB I, 35.3% RCBII and 45.8% RCB III. Ninety percent received adjuvant radiotherapy, 9.2% adjuvant capecitabine and 45% of HR+ adjuvant tamoxifen. We observed recurrence association with HG III ( p = 0,001), Ki67 &gt;20% ( p = 0,001), clinical stage III ( p &lt; 0,001), cT4 and cN2/3 ( p &lt; 0,001), RBC &gt; II/III ( p = 0,001), molecular subtypes HR+/HER2- and HR-/HER2- ( p = 0,042), interruption of neoadjuvant therapy ( p = 0,002) and anti-HER2 therapy ( p = 0,012), and use of adjuvant tamoxifen ( p &lt; 0,001). Adjuvant capecitabin and radiotherapy had no correlation with the outcome. Conclusions: Recurrence was associated with intrinsic factors, such as HG III, Ki67&gt;20%, cT4, cN3/4 and molecular subtype, as well as RCB &gt; II/III, treatment interruption and choice of adjuvant hormonal therapy, pointing out possible risk factors in our population.

Phase III study to evaluate the efficacy and safety of GLSI-100 (GP2 + GM-CSF) in breast cancer patients with residual disease or high-risk PCR after both neoadjuvant and postoperative adjuvant anti-HER2 therapy: Flamingo-01.

TPS617 Background: GP2 is a biologic nine amino acid peptide of the HER2/ neu protein delivered in combination with Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) that stimulates an immune response targeting HER2/neu expressing cancers, the combination known as GLSI-100. In a prospective, randomized, single-blinded, placebo-controlled, multicenter Phase IIb study, no recurrences were observed in the HER2+ population after 5 years of follow-up, if the patient was treated with GLSI-100, survived, and was followed for more than 6 months ( p = 0.0338). Immunotherapy elicited a potent response measured by skin tests and immunological assays. Of the 146 patients that have been treated with GLSI-100 over 4 clinical trials, GLSI-100 was well-tolerated and no serious adverse events observed were considered related to the immunotherapy. Methods: This Phase III trial is a prospective, randomized, double-blinded, multi-center study. After 1 year of trastuzumab-based therapy, 6 intradermal injections of GLSI-100 or placebo will be administered over the first 6 months and 5 subsequent boosters will be administered over the next 2.5 years for a total of 11 injections over 3 years. The participant duration of the trial will be 3 years treatment plus 1 additional year follow-up for a total of 4 years following the first year of treatment with trastuzumab-based therapy. Patients will be stratified based on residual disease status at surgery, hormone receptor status and region. Approximately 498 patients will be enrolled. To detect a hazard ratio of 0.3 in invasive breast cancer free survival (IBCFS), 28 events will be required. An interim analysis for superiority and futility will be conducted when at least 14 events have occurred. This sample size provides 80% power if the annual rate of events in placebo patients is 2.4% or greater. Up to 100 non-HLA-A*02 subjects will be enrolled in an open-label arm. The patient population is defined by these key eligibility criteria: HER2/neu positive and HLA-A*02; residual disease or High risk pCR (Stage III at presentation) post neo-adjuvant therapy; exclude stage IV; completed at least 90% of planned trastuzumab-based therapy. Trial objectives were to determine if GP2 therapy increases IBCFS, to assess the safety profile of GP2 and to monitor immunologic responses to treatment and assess relationship to efficacy and safety. The study has been initiated at a number of sites in the US. The study is also expected to be opened in Spain, Germany, and France. Clinical trial information: NCT05232916 .

Impact of body mass index in therapeutic response for HER2 positive breast cancer treated with neoadjuvant targeted therapy: a multi-center study and meta-analysis

While overweight/obesity has become a major public health issue worldwide, any association between body mass index (BMI) and therapeutic response in neoadjuvant targeted therapy treated HER2 positive breast cancer patients remain unclear. The information from a total of four-hundred and ninety-one neoadjuvant targeted therapy treated HER2 positive breast cancer patients from four institutions were retrospectively collected. Univariate and multivariate logistic analysis was developed to determine the association between BMI and therapeutic response. A meta-analysis of published literature was then conducted to confirm the effect of overweight/obesity on pCR for patients treated with neoadjuvant targeted therapy. Restricted cubic spline (RCS) adjusted for confounding factors demonstrated a decrease pCR with increasing BMI (OR = 0.937, P = 0.045). Patients were then categorized into under/normal weight (n = 299) and overweight/obesity (n = 192). Overweight/obese patients were independently associated with a poor therapeutic response. In the subgroup analysis, a significant negative impact of overweight/obesity on pCR can be observed both in single-targeted (OR = 0.556; P = 0.02) and dual-targeted (OR = 0.392; P = 0.021) populations. Six eligible studies involving 984 neoadjuvant targeted therapy treated HER2 positive breast cancer patients were included in the meta-analysis. The meta-analysis also demonstrated that overweight/obesity was significantly associated with a poor response to neoadjuvant anti-HER2 therapy (OR = 0.68; P = 0.007). Our result show that overweight and obese HER2 positive breast cancer patients are less likely to achieve pCR after neoadjuvant targeted therapy.

122TiP Phase III study to evaluate the efficacy and safety of GLSI-100 (GP2 + GM-CSF) in breast cancer patients with residual disease or high-risk PCR after both neo-adjuvant and postoperative adjuvant anti-HER2 therapy, Flamingo-01

122TiP Phase III study to evaluate the efficacy and safety of GLSI-100 (GP2 + GM-CSF) in breast cancer patients with residual disease or high-risk PCR after both neo-adjuvant and postoperative adjuvant anti-HER2 therapy, Flamingo-01

Abstract CT064: Phase III study to evaluate the efficacy and safety of GLSI-100 (GP2 + GM-CSF) in breast cancer patients with residual disease or high-risk PCR after both neo-adjuvant and postoperative adjuvant anti-HER2 therapy, Flamingo-01

Abstract Background: GP2 is a biologic nine amino acid peptide of the HER2/neu protein delivered in combination with Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) that stimulates an immune response targeting HER2/neu expressing cancers, the combination known as GLSI-100. In a prospective, randomized, single-blinded, placebo-controlled, multicenter Phase IIb study, no recurrences were observed in the HER2+ population after 5 years of follow-up, if the patient was treated with GLSI-100, survived, and was followed for more than 6 months (p = 0.0338). Immunotherapy elicited a potent response measured by skin tests and immunological assays. Of the 146 patients that have been treated with GLSI-100 over 4 clinical trials, GLSI-100 was well-tolerated and no serious adverse events observed were considered related to the immunotherapy. Method: This Phase III trial is a prospective, randomized, double-blinded, multi-center study. After 1 year of trastuzumab-based therapy, 6 intradermal injections of GLSI-100 or placebo will be administered over the first 6 months and 5 subsequent boosters will be administered over the next 2.5 years for a total of 11 injections over 3 years. The participant duration of the trial will be 3 years treatment plus 1 additional year follow-up for a total of 4 years following the first year of treatment with trastuzumab-based therapy. Patients will be stratified based on residual disease status at surgery, hormone receptor status and region. Study Size - Interim Analysis: Approximately 498 patients will be enrolled. To detect a hazard ratio of 0.3 in invasive breast cancer free survival (IBCFS), 28 events will be required. An interim analysis for superiority and futility will be conducted when at least 14 events have occurred. This sample size provides 80% power if the annual rate of events in placebo patients is 2.4% or greater. Up to 100 non-HLA-A*02 subjects will be enrolled in an open-label arm. Eligibility Criteria: The patient population is defined by these key eligibility criteria: 1) HER2/neu positive and HLA-A*02; 2) Residual disease or High risk pCR (Stage III at presentation) post neo-adjuvant therapy; 3) Exclude Stage IV; and 4) Completed at least 90% of planned trastuzumab-based therapy. Trial Objectives: 1) To determine if GP2 therapy increases IBCFS; 2) To assess the safety profile of GP2; and 3) To monitor immunologic responses to treatment and assess relationship to efficacy and safety. Study Status: The study has been initiated at a number of sites in the US. The study is also expected to be opened in Spain, Germany, and France. Funding: This trial is supported by Greenwich LifeSciences. Citation Format: Snehal S. Patel, Jaye L. Thompson, Mira S. Patel, F. Joseph Daugherty, Mothaffar F. Rimawi. Phase III study to evaluate the efficacy and safety of GLSI-100 (GP2 + GM-CSF) in breast cancer patients with residual disease or high-risk PCR after both neo-adjuvant and postoperative adjuvant anti-HER2 therapy, Flamingo-01 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT064.

Re-Evaluation of Pathologic Complete Response as a Surrogate for Event-Free and Overall Survival in Human Epidermal Growth Factor Receptor 2-Positive, Early Breast Cancer Treated With Neoadjuvant Therapy Including Anti-Human Epidermal Growth Factor Receptor 2 Therapy.

Pathologic complete response (pCR) has prognostic importance and is frequently used as a primary end point, but doubts remain about its validity as a surrogate for event-free survival (EFS) and overall survival (OS) in human epidermal growth factor receptor 2 (HER2)-positive, early breast cancer. We obtained individual-patient data from randomized trials of neoadjuvant anti-HER2 therapy that enrolled at least 100 patients, had data for pCR, EFS, and OS, and a median follow-up of at least 3 years. We quantified the patient-level association between pCR (defined as ypT0/Tis ypN0) and both EFS and OS using odds ratios (ORs, with ORs >1.00 indicating a benefit from achieving a pCR). We quantified the trial-level association between treatment effects on pCR and on EFS and OS using R2 (with values above 0.75 considered as indicating strong associations). Eleven of 15 eligible trials had data for analysis (3,980 patients, with a median follow-up of 62 months). Considering all trials, we found strong patient-level associations, with ORs of 2.64 (95% CI, 2.20 to 3.07) for EFS and 3.15 (95% CI, 2.38 to 3.91) for OS; however, trial-level associations were weak, with an unadjusted R2 of 0.23 (95% CI, 0 to 0.66) for EFS and 0.02 (95% CI, 0 to 0.17) for OS. We found qualitatively similar results when grouping trials according to different clinical questions, when analyzing only patients with hormone receptor-negative disease, and when using a more stringent definition of pCR (ypT0 ypN0). Although pCR may be useful for patient management, it cannot be considered as a surrogate for EFS or OS in neoadjuvant trials of HER2-positive, operable breast cancer.

Abstract OT2-10-06: Phase III study to evaluate the efficacy and safety of GLSI-100 (GP2 + GM-CSF) in breast cancer patients with residual disease or high-risk PCR after both neo-adjuvant and postoperative adjuvant anti-HER2 therapy, Flamingo-01

Abstract Background: GP2 is a biologic nine amino acid peptide of the HER2/neu protein delivered in combination with Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) that stimulates an immune response targeting HER2/neu expressing cancers, the combination known as GLSI-100. In a prospective, randomized, single-blinded, placebo-controlled, multicenter Phase IIb study, no recurrences were observed in the HER2+ population after 5 years of follow-up, if the patient was treated with GLSI-100, survived and was followed for more than 6 months (p = 0.0338). Immunotherapy elicited a potent response measured by skin tests and immunological assays. Of the 146 patients that have been treated with GLSI-100 over 4 clinical trials, GLSI-100 was well-tolerated and no serious adverse events were observed considered related to the immunotherapy. Method: This Phase III trial is a prospective, randomized, double-blinded, multi-center study. After 1 year of trastuzumab-based therapy, 6 intradermal injections of GLSI-100 or placebo will be administered over the first 6 months and 5 subsequent boosters will be administered over the next 2.5 years for a total of 11 injections over 3 years. The participant duration of the trial will be 3 years treatment plus 1 additional year follow-up for a total of 4 years following the first year of treatment with trastuzumab-based therapy. Patients will be stratified based on residual disease status at surgery, hormone receptor status and region. Study Size – Interim Analysis: Approximately 498 patients will be enrolled. To detect a hazard ratio of 0.3 in invasive breast cancer free survival (IBCFS), 28 events will be required. An interim analysis for superiority and futility will be conducted when at least 14 events have occurred. This sample size provides 80% power if the annual rate of events in placebo patients is 2.4% or greater. Up to 100 non-HLA-A*02 subjects will be enrolled in an open-label arm. Eligibility Criteria: The patient population is defined by these key eligibility criteria: 1. HER2/neu positive and HLA-A*02 2. Residual disease or High risk pCR (Stage III at presentation) post neo-adjuvant therapy 3. Exclude Stage IV 4. Completed at least 90% of planned trastuzumab-based therapy Trial Objectives: 1. To determine if GP2 therapy increases IBCFS 2. To assess the safety profile of GP2 3. To monitor immunologic responses to treatment and assess relationship to efficacy and safety Contact information: Snehal Patel Greenwich LifeSciences, Inc. Stafford, TX Email: snehal.patel@greenwichlifesciences.com Website: greenwichlifesciences.com Funding: This trial is supported by Greenwich LifeSciences. Citation Format: Snehal Patel, Jaye Thompson, Mira Patel, F. Joseph Daugherty, C. Kent Osborne, Mothaffar Rimawi. Phase III study to evaluate the efficacy and safety of GLSI-100 (GP2 + GM-CSF) in breast cancer patients with residual disease or high-risk PCR after both neo-adjuvant and postoperative adjuvant anti-HER2 therapy, Flamingo-01 [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT2-10-06.

Abstract P4-07-62: Real-World, Single-Center Experience on the Outcomes of Neoadjuvant Chemotherapy and Trastuzumab alone or in Combination with Pertuzumab in Human Epidermal Growth Factor Receptor 2 Breast Cancer Patients

Abstract Background: Neoadjuvant chemotherapy is the standard of care for early stage breast cancer. Human epidermal growth factor receptor 2 (HER2) positive disease constitutes a large proportion of breast cancer patients, and HER2 overexpression is associated with poor prognosis. The induction of HER2+ targeted therapies, such as trastuzumab and pertuzumab, has resulted in improved outcomes in HER2+ breast cancers. Neoadjuvant chemotherapy in combination with HER2 targeted therapies aims at achieving pathological complete response (pCR) and an improved survival. Methods: We performed a retrospective review of HER2+ breast cancer patients who were treated at Medanta – The Medicity Hospital, Gurugram, Haryana, India, between 2011 and 2021. A total of 108 HER2+ breast cancer patients who received neoadjuvant chemotherapy with platinum, anthracycline or taxane-based regimens, along with trastuzumab alone or in combination with pertuzumab, were included. Results: Of 108 enrolled patients, 66 and 42 patients received single-blockade (trastuzumab) and dual-blockade (trastuzumab and pertuzumab) neoadjuvant anti-HER2 therapy, respectively. The majority of patients were aged &amp;lt; 60 years. The patient populations were comparable in terms of clinical stage, hormone receptor status, histopathology category (IDC being most common) and Ki67 status for single- and dual-blockade groups. All patients had IHC3+/FISH+ HER2 expression. No significant (p=0.896) difference was observed for breast conserving surgery between the groups. A higher pCR rate after surgery was reported in the dual-blockade group versus single-blockade group (50% vs. 39.2%; p=0.271). The median follow-up duration was 21.9 and 15.2 months in the single-blockade and dual-blockade groups, respectively. For dual- vs. single- blockade groups, the 1-year OS rates were 100% vs. 100%, and 3-year OS rates were 100% vs. 98.48%. For dual- vs. single- blockade groups, the 1-year DFS rates were 100% vs. 95.45%, and 3-year DFS rates were 92.85% vs. 80.3%. Conclusion: Neoadjuvant chemotherapy with dual HER2-blockade had higher pCR and survival rates compared with the single HER2-blockade strategy in HER2 positive breast cancer. Table. Patient characteristics BCS, breast conserving surgery; ER, estrogen receptor; PR, progesterone receptor; IDC, invasive ductal carcinoma; ILC, invasive lobular carcinoma. Citation Format: Ashok K. Vaid, Devender Sharma, Jyoti Wadhwa, Rajeev Agarwal, Kanchan Kaur, Shina Goyal, Dheeraj Gautam, Jyoti Arora, Sabhyata Gupta, Ashok Sen, Ruchika K. Goel, Shagun Mahajan. Real-World, Single-Center Experience on the Outcomes of Neoadjuvant Chemotherapy and Trastuzumab alone or in Combination with Pertuzumab in Human Epidermal Growth Factor Receptor 2 Breast Cancer Patients [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-62.

Real-life analysis of neoadjuvant-therapy-associated benefits for pathological complete response and survival in early breast cancer patients - role of trastuzumab in HER2+ BC and platinum in TNBC.

Neoadjuvant therapy, which aims to achieve a pathological complete response (pCR) for better overall survival (OS) has several advantages for patients with early breast cancer (eBC) and subtypes of HER2-positive (HER2+) and triple-negative breast cancer (TNBC). However, there has been no large-scale real-world investigation on the clinical outcomes associated with trastuzumab-based and platinum-based neoadjuvant treatments for patients with HER2+ and TNBC, respectively. Taiwan Cancer Registry and National Health Insurance Research Database were utilized in this study. Patients diagnosed with clinically lymph-node-positive (LN+) HER2+ or TNBC were identified for analysis. Logistic regression and Cox proportional hazard models were employed to estimate the adjusted odds ratios (aOR) of achieving pCR and adjusted hazard ratios (aHR) of overall survival associated with treatment agents, respectively. A total of 1,178 HER2+ eBC and 354 early TNBC patients were identified, respectively. Neoadjuvant trastuzumab significantly increased the pCR rates by 3.87-fold among HER2+ patients. Trastuzumab-associated survival benefit was found in HER2+ patients who achieved pCR (aHR [95% CI]: 0.30 [0.11-0.84]) but not in those without pCR (1.13 [0.77-1.67]). Among the TNBC patients, platinum was associated with a 1.6-fold increased pCR rate; however, it did not improve OS regardless of pCR status. Trastuzumab improved pCR and OS for patients with HER2+ subtype. Using platinum agents for TNBC patients increased pCR rates but was not linked to better survival. Optimal neoadjuvant anti-HER2 therapy for patients with HER2+ eBC and the introduction of novel therapy for patients with TNBC should be considered.