Eastern Cooperative Oncology Group Performance Research Articles

Assessment of safety and efficacy of transarterial chemoembolization combined with camrelizumab and donafenib in patients with hepatocellular carcinoma at BCLC stage C: A study of 20 cases.

Camrelizumab, donafenib, and transarterial chemoembolization (TACE) are recommended for advanced hepatocellular carcinoma (HCC), but their combined efficacy remains unclear. From July 2021 to January 2023, 20 Barcelona Clinic Liver Cancer stage C HCC patients were prospectively enrolled. Inclusion criteria were Eastern Cooperative Oncology Group performance status of 0 or 1, Child-Pugh Score ≤ 7, and Barcelona Clinic Liver Cancer B or C. Surgical candidates were excluded. The treatment included TACE, camrelizumab, and donafenib. Endpoints were median overall survival, progression-free survival, and adverse events (AEs) related to donafenib. Among 20 patients, 85% experienced AEs from targeted therapy and programmed cell death protein-1, with 40% having grade 3 AEs. No grade 4 or 5 AEs occurred. Median follow-up was 9 months, with 15% achieving complete response, 65% partial response, and 15% stable disease. Disease control rate was 90%. Median progression-free survival and overall survival were 9 and 14 months, respectively. TACE, camrelizumab, and donafenib combination therapy in Chinese advanced HCC patients show effectiveness in extending survival with low severe AEs incidence.

Bellmunt risk score as a survival predictor in patients with metastatic castration-resistant prostate cancer.

The prognosis of metastatic castration-resistant prostate cancer (mCRPC) is influenced by numerous individual factors. Despite various proposed prognostic models, the clinical application of these remains limited, probably due to complexity. Our study aimed to evaluate the predictive value of the Bellmunt risk score, which is well-known for urothelial carcinoma and easily assessed, in mCRPC patients. The Bellmunt risk score was calculated from three risk factors (Eastern Cooperative Oncology Group Performance Status (ECOG PS) ≥1, serum hemoglobin <10 g/dL, presence of liver metastases) in 125 patients who received first-line mCRPC treatment between 2005 and 2023. In addition, a modified score was established (one point each for hemoglobin <10 g/dL and the presence of liver metastases added to the ECOG PS). Associations with overall survival (OS) under first- and second-line therapy were tested using Cox regression analyzes, log-rank tests, concordance index (C-index) and time-dependent receiver operating characteristic. There is a significant correlation between the level of the Bellmunt risk score and shorter OS (hazard ratio: 3.23, 95% confidence interval: 2.06-5.05; log-rank p < 0.001; C-index: 0.724). The semi-quantitative modified risk score showed even better prognostic discrimination (log-rank p < 0.001, C-index: 0.764). The score and its dynamics were also predictive in the second-line setting (log-rank p < 0.001 and = 0.01; C-index: 0.742 and 0.595). The Bellmunt risk score is easy to assess and provides useful prognostic information in mCRPC, and can support physicians in their treatment decisions.

Pertuzumab Plus Trastuzumab in Patients With Biliary Tract Cancer With ERBB2/3 Alterations: Results From the Targeted Agent and Profiling Utilization Registry Study.

Targeted Agent and Profiling Utilization Registry is a phase II basket trial evaluating the antitumor activity of commercially available targeted agents in patients with advanced cancer and genomic alterations known to be drug targets. Results of a cohort of patients with biliary tract cancer (BTC) with ERBB2/3 amplification, overexpression, or mutation treated with pertuzumab plus trastuzumab are reported. Eligible patients had advanced BTC, measurable disease (RECIST v1.1), Eastern Cooperative Oncology Group performance status 0-2, adequate organ function, tumors with ERBB2/3 alterations, and a lack of standard treatment options. Simon's two-stage design was used with a primary end point of disease control (DC), defined as objective response (OR) or stable disease of at least 16+ weeks duration (SD16+) according to RECIST v1.1. Secondary end points included OR, progression-free survival, overall survival, duration of response, duration of stable disease, and safety. Twenty-nine patients were enrolled from February 2017 to January 2022, and all had advanced BTC with an ERBB2/3 alteration. One patient was not evaluable for efficacy. One complete response, eight partial responses, and two SD16+ were observed for DC and OR rates of 40% (90% CI, 27 to 100) and 32% (95% CI, 16 to 52), respectively. The null hypothesis of 15% DC rate was rejected (P = .0015). Four patients had at least one grade 3 adverse event (AE) or serious AE at least possibly related to treatment: anemia, diarrhea, infusion-related reaction, and fatigue. Pertuzumab plus trastuzumab met prespecified criteria to declare a signal of activity in patients with BTC and ERBB2/3 amplification, overexpression, or mutation.

Prognostic value of skeletal muscle measured by CT at the T4 level in advanced EGFR-positive non-small cell lung cancer patients treated with ecotinib

Objective: To investigate the prognostic value of skeletal muscle measured by CT at the level of the fourth thoracic vertebra (T4) in advanced epidermal growth factor receptor (EGFR)-positive non-small cell lung cancer (NSCLC) patients treated with ecotinib. Methods: The study retrospectively reviewed clinical and pathological characteristics of 176 patients with advanced EGFR-positive NSCLC who received ecotinib and underwent chest CT scans at Wuhan Union Hospital between January 2017 and October 2020. Among them, 70 were male and 106 were female, with ages ranging from 27 to 80 (58.6±10.6) years. As of August 21, 2021, the median follow-up duration was 19.2 months (95%CI: 15.3 to 23.7 months). The optimal cut-off value of skeletal muscle density (T4-SMD) on CT images at the T4 level were determined using X-tile software. Kaplan-Meier analysis and log-rank test were used to plot progression-free survival curves. Cox proportional hazards regression models were employed to analyze factors influencing 1-year progression-free survival (PFS), and a nomogram prognostic model was constructed accordingly. Receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA) were utilized to evaluate the predictive value of the nomogram. Results: The T4-SMD [M (Q1,Q3)] of 176 patients was 42.56 (37.05, 45.93) HU. Patients were divided into low T4-SMD group (n=122) and high T4-SMD group (n=54) based on the cut-off value (The values for males and females were 49.44 and 41.41 HU, respectively) of T4-SMD. The median PFS time and 1-year PFS rate in the low T4-SMD group were significantly lower than those in the high T4-SMD group [10.4 (95%CI: 9.3-11.8) vs 13.7 (95%CI: 11.1-18.5) months, 36.1% vs 59.3%, respectively, P=0.034]. Eastern Cooperative Oncology Group performance status (HR=3.308, 95%CI: 1.183-9.247, P=0.023), lactate dehydrogenase level (HR=1.852, 95%CI: 1.037-3.307, P=0.037), systemic immune-inflammation index (HR=1.772, 95%CI: 1.019-3.080, P=0.043), and T4-SMD (HR=0.563, 95%CI: 0.325-0.974, P=0.040) were prognostic factors for 1-year PFS in advanced EGFR-positive NSCLC patients treated with ecotinib. A nomogram for predicting 1-year PFS of advanced EGFR-positive NSCLC patients treated with ecotinib was constructed based on the four indicators selected by multivariate Cox regression analysis. The area under the ROC curve of the nomogram was 0.775 (95%CI: 0.676-0.874). The calibration curve showed good consistency between the predicted and actual 1-year PFS. DCA demonstrated good clinical prediction effectiveness of the nomogram. Conclusion: Low T4-SMD is a prognostic risk factor for patients with advanced EGFR-positive NSCLC receiving icotinib therapy.

Palliative Surgery for Patients with Gastroesophageal Junction or Gastric Cancer: A Report on Clinical Observational Outcomes.

Few studies have focused on palliative surgery in patients with advanced gastroesophageal junction (GEJ) or gastric cancer. We sought to evaluate clinical observational outcomes following palliative surgery in this population. Patients with GEJ or gastric cancer who underwent palliative surgery (1/2010-11/2022) were identified. The primary outcomes were symptom improvement, ability to tolerate an oral diet, discharge to home, 30 "good days" without hospitalization, and receipt of systemic treatment. Postoperative outcomes and survival were secondarily evaluated. Among 93 patients, the median age was 59 (IQR 47-68) years, and the median Eastern Cooperative Oncology Group Performance Status (ECOG-PS) was 1 (range 0-3). The most frequent indication for palliative surgery was primary tumor obstruction [75 (81%) patients]. The most common procedures were feeding tube placement in 60 (65%) and intestinal bypass in 15 (16%) patients. A total of 75 (81%) patients experienced symptom improvement. Of these, 19 (25%) developed recurrent and 49 (65%) developed new symptoms. ECOG-PS was significantly associated with symptom-free time. Among those who underwent a bypass, resection, or ostomy creation for malignant obstruction, 16 (80%) tolerated an oral diet. Postoperatively, 87 (94%) were discharged home, 72 (77%) had 30 good days, and 64 (69%) received systemic treatment. Postoperative complications occurred in 35 (38%) patients, and 7 (8%) died within 30 days. The median survival time was 7.7 (95% CI 6.4-10.40) months. Patients with incurable GEJ or gastric cancer can benefit from palliative surgery. Prognosis and performance status should inform goals-of-care discussions and patient selection for surgical palliation.

Combination anlotinib and toripalimab for an advanced biliary tract cancer patient with high Eastern Cooperative Oncology Group performance status: a case report.

Up to 80% of biliary tract cancer (BTC) patients relapse within 3 years after surgery and the efficacy of second-line treatment remains dismal for patients who progressed on gemcitabine and cisplatin chemotherapy. Median overall survival of patients with palliative chemotherapy is less than 1 year. The feasibility and safety of targeted therapies plus immunotherapies remain scanty currently, and patients with recurrent or advanced BTCs often experience a rapid decline in Eastern Cooperative Oncology Group (ECOG) performance status. This case report is the first report suggesting a 17-month progression-free survival (PFS), partial response, and another 11-month PFS after progressive disease of anlotinib plus toripalimab in advanced BTC with high ECOG performance status. We report a 67-year-old Chinese male with BTC. He was observed with progressive disease after surgical resection, adjuvant chemotherapy, palliative chemotherapy, and diagnosed with American Joint Committee on Cancer clinical stage IV (cT3N0M1) extrahepatic BTC. The patient experienced a rapid decline in performance status, and he received oral anlotinib and toripalimab with informed consent. MRI scans showed partial response on 22 June 2022. PET-CT showed that tumor activity has been inhibited on 8 March 2023. He achieved 17 months of PFS. Although the patient developed solitary lung metastasis, he had a continuous survival benefit from treatment of anlotinib plus toripalimab after lung radiotherapy. Until the writing of the case draft, he had achieved another 11 months of PFS. The present case suggests that anlotinib plus toripalimab might be a potential effective treatment for advanced BTCs patients with high ECOG performance status.

Outcomes of patients with hepatocellular carcinoma treated with atezolizumab plus bevacizumab in real-world clinical practice who met or did not meet the inclusion criteria for the phase 3 IMbrave150 trial.

Atezolizumab plus bevacizumab (Atezo/Bev) is frequently selected as the primary systemic therapy for hepatocellular carcinoma (HCC). To investigate the outcomes of patients with HCC treated with Atezo/Bev in a real-world setting based on whether they met the inclusion criteria for the phase 3 IMbrave150 trial. A total of 936 patients were enrolled. There were 404 patients who met the inclusion criteria of the phase 3 IMbrave150 trial (IMbrave150 group) and 532 who did not (non-IMbrave150 group). Median progression-free survival (PFS) in the IMbrave150 and non-IMbrave150 groups was 7.4 months and 5.6 months (p = 0.002). Multivariable analysis revealed that non-B, non-C HCC aetiology (hazard ratio [HR], 1.173), α-fetoprotein ≥100 ng/mL (HR, 1.472), Barcelona Clinic Liver Cancer stage ≥ C (HR, 1.318), and modified albumin-bilirubin (mALBI) grade 2b or 3 (HR, 1.476) are independently associated with PFS. Median overall survival (OS) in the IMbrave150 and non-Imbrave150 groups was 26.5 and 18.8 months (p < 0.001). Multivariable analysis revealed that Eastern Cooperative Oncology Group performance status ≥2 (HR, 1.986), α-fetoprotein ≥100 ng/mL (HR, 1.481), and mALBI grade 2b or 3 (HR, 2.037) are independently associated with OS. In subgroup analysis, there were no significant differences in PFS or OS between these groups among patients with mALBI grade 1 or 2a. Patients who are treated with Atezo/Bev and meet the inclusion criteria for the phase 3 IMbrave150 trial, as well as those who do not meet the inclusion criteria but have good liver function, have a good prognosis for survival.

Anticancer therapy at end-of-life: A retrospective cohort study.

A significant proportion of patients with incurable cancer receive systemic anticancer therapy (SACT) within their last 30 days of life (DOL). The treatment has questionable benefit, nevertheless is considered a quality indicator of end-of-life (EOL) care. This retrospective cohort study aims to investigate the rates and potential predictors of SACT and factors associated with SACT within the last 30 DOL. The study also evaluates the scope of Eastern Cooperative Oncology Group (ECOG) performance status and the modified Glasgow prognostic score (mGPS) as decision-making tools for oncologists. This review of medical records included 383 patients with non-curable cancer who died between July 2018 and December 2019. Descriptive statistics with Chi-squared tests and regression analysis were used to identify factors associated with SACT within the last 30 DOL. Fifty-seven (15%) patients received SACT within the last 30 DOL. SACT within 30 last DOL was associated with shorter time from diagnosis until death (median 234 days vs. 482, p = 0.008) and ECOG score < 3 30 days prior to death (p = 0.001). Patients receiving SACT during the last 30 DOL were more likely to be hospitalised and die in hospital. ECOG and mGPS score were stated at start last line of treatment only in 139 (51%) and 135 (49%) respectively. Those with short time since diagnosis tended to receive SACT more frequently the last 30 DOL. The use of mGPS as a decision-making tool is modest, and there is lack in documentation of performance status.

Phase II study to determine the anti-tumor activity and safety of simlukafusp alfa (FAP-IL2v) combined with atezolizumab in esophageal cancer.

Reported here are results from the esophageal squamous cell carcinoma (SCC) cohort of a Phase II, non-comparative, basket study, evaluating the anti-tumor activity and safety of FAP-IL2v plus atezolizumab in patients with advanced/metastatic solid tumors (NCT03386721). Eligible patients had an Eastern Cooperative Oncology Group performance status of 0-1; measurable metastatic, persistent, or recurrent esophageal SCC; progression on ≥1 prior therapy; and were checkpoint inhibitor naive. Patients received FAP-IL2v 10 mg plus atezolizumab 1200 mg intravenously every 3 weeks, or FAP-IL2v weekly for 4 weeks, then every 2 weeks, plus atezolizumab 840 mg intravenously every 2 weeks. Primary endpoint was investigator-assessed objective response rate (ORR). In the response-evaluable population (N=34), best confirmed ORR was 20.6% (95% confidence interval [CI]: 10.4-36.8) with a complete response (CR) seen in one patient and partial responses (PR) in six patients. Disease control rate was 44.1% (CR=2.9%; PR=17.6%; stable disease [SD]=23.5%) and median duration of response was 10.1 months (95% CI: 5.6-26.7). Median progression-free survival was 1.9 months (95% CI: 1.8-3.7). Analysis of response by PD-L1 expression (Ventana SP263) resulted in an ORR of 26.7 % for patients with PD-L1-positive tumors (tumor area positivity [TAP] cut-off ≥1%; n=15) and 7.1% for patients with PD-L1-negative tumors (TAP cut-off <1%; n=14). Overall, the treatment combination was tolerable and adverse events were consistent with the known safety profiles of each drug. FAP-IL2v plus atezolizumab demonstrated clinical activity and was tolerable in patients with previously treated esophageal SCC.

Advanced cutaneous squamous cell carcinoma: Impact of age on the safety and efficacy of cemiplimab and the prognostic significance of blood biomarkers

IntroductionAge-related differences in the safety profile of cemiplimab for patients with locally advanced or metastatic cutaneous squamous cell carcinoma (cSCC) have not been well described. We investigated the association of increasing age with immune related adverse events (irAE) from cemiplimab, efficacy outcomes, and the prognostic significance of pre-treatment blood biomarkers in contemporary practice. Materials and MethodsPatients starting first-line cemiplimab for locally advanced or metastatic cSCC at British Columbia Cancer between April 2019 and January 2023 were identified. Landmark four-month logistic regression analysis compared the odds of developing irAE or sequelae amongst patients aged <75 years to those aged 75–84 or ≥ 85. Objective responses were determined using Response Evaluation Criteria in Solid Tumors version 1.1. Univariable Cox proportional hazard (PH) regression modelling of factors associated with overall survival (OS) was performed. ResultsOf 106 patients, the proportions aged <75, 75–84, and ≥ 85 years were 34%, 45%, and 21%, respectively. Overall, the proportion of patients with irAE ≥ grade 3, cemiplimab discontinuation, and hospitalization for immune toxicity was 27.4%, 31.1%, and 11.3%, respectively. There was no clear association between age and the odds of high grade irAE. However, increased odds of cemiplimab discontinuation was observed in patients aged 75–84 years (p = 0.05). Patients ≥85 years had increased hospitalizations due to irAE (OR = 5.00, 95% CI = 0.97–37.52) with two treatment-related deaths. Objective responses were similar across age cohorts (50.0%, 60.4%, and 54.5%) but progressive disease was higher in the age ≥ 85 group (22.2%, 18.8%, and 31.8%). On Cox PH regression analysis, age ≥ 85 years (vs. <75), Eastern Cooperative Oncology Group performance status 2–3 (vs. 0–1), and neutrophil to lymphocyte ratio (NLR) ≥7.80 (vs. <7.80) were associated with shorter survival. DiscussionWhile the odds of high grade irAE were similar across age groups, significant age-related differences in treatment discontinuation and hospitalization due to immune toxicity were observed. Despite a higher incidence of primary progression and shorter OS in the oldest cohort, cemiplimab yielded robust objective responses regardless of age. Higher pre-treatment NLR was associated with shorter survival and the cut-point identified requires further study.

Factors Associated With Prescription of Systemic Therapy in Real-world Patients With Metastatic Renal Cell Cancer Managed in a Rural Region.

Numerous new treatment options have been approved for metastatic renal cell carcinoma (mRCC) in the last decade. Nevertheless, not all patients receive systemic therapy. Certain patients present with very advanced disease, poor Eastern Cooperative Oncology Group performance status (ECOG PS), or severe comorbidity, i.e. factors that lead oncologists to prefer best supportive care (BSC) instead of systemic therapy. The aim of this quality-of-care study was to identify baseline factors (disparities) associated with receipt of systemic therapy rather than BSC. This retrospective analysis included 140 consecutive patients managed in a rural region of Norway (2007-2022). Two differently managed groups were compared in univariate tests followed by multi-nominal regression. The majority of patients (n=95, 68%) had received systemic therapy. Typical patients were males in their 60s or 70s, with clear cell histology, prior nephrectomy, and intermediate prognostic features. Patients who received systemic therapy lived significantly longer than those who did not (median 30.4 versus 5.0 months, p<0.001). Survival benefit of systemic treatment was observed even in patients with ECOG PS3 or age ≥80 years. In addition to younger age (p<0.001) and better ECOG PS (p<0.001), metachronous presentation was associated with higher rates of systemic therapy utilization (p=0.03). Assignment to systemic therapy for mRCC was individualized in the present patient population. In all age and ECOG PS subgroups, systemic therapy was associated with better survival (doubling at least). Optimum utilization rates are difficult to determine. However, in light of the survival outcomes, a rate of 12% in patients aged 80 years or older appears rather low.

Abstract PO3-17-07: Real-world experience with trastuzumab deruxtecan in patients with breast cancer: 6 month-interim analysis of an all-patient postmarketing surveillance in Japan

Abstract Background: Trastuzumab deruxtecan (T-DXd) is an anti-human epidermal growth factor receptor 2 (HER2) antibody-drug conjugate. T-DXd has shown great efficacy in HER2-positive breast cancer, hence receiving approval in Japan in March 2020. In Japan, all-patient postmarketing surveillance (PMS) is underway to evaluate the risk of interstitial lung disease/pneumonitis (ILD/p) in patients with breast cancer treated with T-DXd. Due to the limited generalizability of results from clinical trials, there is a need for more information about ILD/p in a real-world setting. Herein we present an interim analysis of the large-scale all-patient PMS. Methods: This is an observational, multicenter, all-patient PMS (jRCT1080225197) with an observation period of 18 months that enrolled all patients treated with T-DXd for recurrent/advanced HER2-positive breast cancer. Patients who initiated T-DXd treatment between May 2020 (launch date of T-DXd) and May 2021 were included in the interim analysis to ensure the observation period of 6 months from the initial treatment of T-DXd. This interim analysis is based on safety data from the first 6 months of 1204 patients. Data collected includes baseline characteristics and information on ILD/p. All potential ILD/p (identified based on the AE terms) reported by physicians were adjudicated by an independent ILD adjudication committee. The incidence of ILD/p was calculated from adjudicated drug-related ILD/p. Results: The interim analysis set included 1204 patients with median age of 60 years. Three of the 1204 patients (0.2%) received T-DXd as a first-line treatment, 30 (2.5%) as second-line, 1159 (96.3%) as third- line or later treatment. At baseline, 105 (8.7%) of patients had an Eastern Cooperative Oncology Group performance status (ECOG PS) 2 or greater, 8 (0.7%) had severe renal impairment (15≤ creatinine clearance (CLcr) &amp;lt; 30 mL/min), 4 (0.3%) had end-stage renal disease (CLcr &amp;lt; 15 mL/min), 5 (0.4%) had severe liver impairment (total bilirubin &amp;gt;4.5 mg/dL), and 32 (2.7%) had comorbid ILD/radiation pneumonitis. Those were defined as exclusion criteria in clinical trials of T-DXd. The median dose at the start of administration of T-DXd was 5.4 mg/kg (range:2.7-5.4). During the first 6 months from the initial treatment, T-DXd was discontinued in 403 (33.5%) of the 1204 patients. The most common reasons for discontinuation were disease progression in 232 (57.6%) of the discontinued 403 patients followed by ILD/p in 97 (24.1%) of the 403 patients. In the first 6 months, the incidence of all grade, grade ≥3, and grade 5 ILD/p were 8.2% (n=99), 1.7% (n=20) and 0.4% (n=5), respectively. The incidence of ILD/p stratified by baseline characteristics identified as potential risk factors of drug-related ILD/p is shown in Table. Conclusion: This is the first report demonstrating real-world experience with T-DXd in Japan. The interim analysis revealed useful information including patient and treatment profiles of T-DXd and the incidence of ILD/p during the first 6 months from the initial treatment in a real-world setting in Japan. The final analysis of the ongoing PMS is warranted for further evaluation. Incidence of interstitial lung disease/pneumonitis by patient baseline characteristics XX XX ILD/p: interstitial lung disease/pneumonitis, 95% CI: 95% confidence interval, CLCr: creatinine clearance using the Cockcroft-Gault equation * includes ILD/p, pulmonary fibrosis, radiation pneumonitis, chronic obstructive pulmonary disease, emphysema, and Asthma (Source: Powell CA, Modi S, Iwata H, et al. Pooled analysis of drug-related interstitial lung disease and/or pneumonitis in nine trastuzumab deruxtecan monotherapy studies. ESMO Open 2022;7(4):100554) Citation Format: Junji Tsurutani, Hideki Mizutani, Ayumi Tanabe. Real-world experience with trastuzumab deruxtecan in patients with breast cancer: 6 month-interim analysis of an all-patient postmarketing surveillance in Japan [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 PO3-17-07.

Abstract PO1-06-03: Efficacy of First-line Treatments for Hormone Receptor-positive, Human Epidermal Growth Factor Receptor 2-positive Metastatic Breast Cancer: A Systematic Literature Review and Network Meta-analysis Feasibility Assessment

Abstract Background: A comprehensive summary of clinical evidence for first-line (1L) treatments for hormone receptor-positive, human epidermal growth factor receptor 2-positive (HR+/HER2+) advanced or metastatic breast cancer (mBC) is needed to understand which treatments have been evaluated and the outcomes associated with different treatments. Understanding the available clinical evidence for HR+/HER2+ mBC 1L treatments can also inform the feasibility of network meta-analyses (NMAs) to estimate relative treatment effects where head-to-head trials are not available. The objective was to prepare a systematic summary of clinical trials of 1L treatments for HR+/HER2+ mBC and assess the feasibility of NMAs for key efficacy outcomes. Methods: A systematic literature review (SLR) was conducted per Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Clinical trials evaluating 1L treatments for adults with HR+/HER2+ mBC published between January 2000 and January 2023 were identified via predefined searches of databases (Embase, MEDLINE, Cochrane Library), relevant congress proceedings, and ClinicalTrials.gov (updating a previous SLR covering January 2000 to December 2020). Study design characteristics, patient characteristics, and efficacy outcomes were extracted from identified trials. An NMA feasibility assessment that considered network connectivity and cross-study heterogeneity was conducted for four efficacy outcomes of interest: progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and clinical benefit rate (CBR). Results: After screening, 37 records reporting on 23 unique studies (11 randomized controlled trials [RCTs] and 12 single-arm trials; 35 study arms in total) were selected. Included trials were mostly phase II or phase III multi-country studies that evaluated a HR+ or HER2+ population, with outcomes being reported for the subgroup of patients with the HR+/HER2+ subtype. Treatments evaluated included one or two anti-HER2 therapies (AHTs) + endocrine therapy (ET) (5/35 study arms), AHTs + chemotherapy (CT) (20/35), AHTs + ET + CT (2/35), AHTs alone (5/35), and ET alone (3/35). For HR+/HER2+ patients, PFS and OS were reported by 17/23 and 10/23 studies, respectively. Reported median PFS and OS ranged from 2.4-23.7 months and 23.9-66.7 months, respectively. Among the 11 included RCTs, hazard ratios and/or Kaplan-Meier curves, which were considered a requirement for NMAs for time to event outcomes, were reported for PFS and OS by 9 and 6 studies, respectively. Among these studies, reported median PFS and OS ranged from 2.4-19.2 months and 23.9-57.9 months, respectively. For HR+/HER2+ patients, ORR and CBR were reported by 13/23 and 6/23 studies, respectively. Assuming all CTs could be considered equivalent treatments and all ETs could be considered equivalent treatments, NMAs involving networks of 9, 6, 6, and 3 treatments were feasible for PFS, OS, ORR, and CBR, respectively. Some patient characteristics including time since mBC diagnosis and proportion with bone metastases were not reported consistently across trials. However, included studies were broadly comparable based on study design characteristics, outcome definitions and other reported patient characteristics such as age and Eastern Cooperative Oncology Group performance status. Conclusion: Clinical trials in 1L HR+/HER2+ mBC have evaluated various combinations of AHTs, CTs, and ETs, with most study arms being AHTs + CT. Although efficacy outcomes of interest were not consistently reported across trials, NMAs were found to be feasible for PFS, OS, ORR, and CBR based on available data. Citation Format: Priyanka Sharma, Chau Dang, Christopher Drudge, Amrita Debnath, Manvir Rai, Eric Gauthier, Edward Broughton. Efficacy of First-line Treatments for Hormone Receptor-positive, Human Epidermal Growth Factor Receptor 2-positive Metastatic Breast Cancer: A Systematic Literature Review and Network Meta-analysis Feasibility Assessment [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 PO1-06-03.

Abstract PO3-18-09: OPERA-01: A randomized, open-label, phase 3, study of palazestrant (OP-1250) vs standard-of-care treatment for ER+, HER2- advanced or metastatic breast cancer after endocrine and CDK4/6 inhibitor therapy

Abstract Background: In estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC), adding a cyclin-dependent kinase 4/6 (CDK4/6) inhibitor to endocrine therapy (ET) has improved outcomes and is the current standard-of-care treatment in the first-line setting. However, resistance to first-line treatment develops in most patients (pts), which is often attributed to acquired mutations in ESR1. Limited data exist for ET-based treatment options after progression on prior ET and CDK4/6 inhibitors, and most pts will transition to chemotherapy for further treatment. Therefore, there is a significant unmet need for more effective ET in pts with ER-positive, HER2-negative MBC to improve outcomes and delay time to chemotherapy. Palazestrant (OP-1250) is a small molecule oral complete ER antagonist (CERAN) and selective ER degrader (SERD) that binds the ligand binding domain of ER and completely blocks ER-driven transcriptional activity in both wild-type (ESR1-wt) and mutant (ESR1-mut) forms of ER. In preclinical studies, palazestrant demonstrated better tumor shrinkage in ESR1-wt and ESR1-mut models when compared to fulvestrant; it also showed efficacy in brain metastasis models. In a phase 1/2 monotherapy study in pts with heavily pretreated ER-positive, HER2-negative advanced breast cancer (BC) or MBC (NCT04505826), palazestrant showed a tolerable safety profile, promising antitumor efficacy, and favorable pharmacokinetics (PK) supporting once a day (qd) dosing. The recommended Phase 2 dose of palazestrant is 120 mg qd. Methods: The OPERA-01 trial is an international, multicenter, randomized, open-label, phase 3 clinical trial comparing the efficacy and safety of palazestrant as a single agent to standard-of-care ET (fulvestrant, anastrozole, letrozole, or exemestane) in pts with ER-positive, HER2-negative advanced BC or MBC that has relapsed or progressed on 1 or 2 prior lines of ET for MBC, which includes a CDK4/6 inhibitor. Eligible pts are women (pre- or post-menopausal) or men who have a confirmed diagnosis of ER-positive, HER2-negative locally advanced evaluable BC or MBC not amenable to curative therapy. ER and HER2 status are determined according to the American Society of Clinical Oncology/College of American Pathologists guidelines. Patients must have Eastern Cooperative Oncology Group performance status 0 or 1. Prior treatments must include 1 or 2 prior lines of ET as monotherapy or in combination with a CDK4/6 inhibitor for MBC; must have received CDK4/6 inhibitor in combination with ET and have disease progression during or within 28 days of completion of each line of prior treatment for MBC; most recent ET given for ≥6 months. Prior chemotherapy in the metastatic setting is not permitted. Patients (N∼500) are randomized to palazestrant or standard-of-care ET monotherapy, and are stratified by ESR1 mutation status, prior lines of ET for advanced disease (1 vs 2 lines), and presence or absence of visceral disease. The primary endpoint of progression-free survival will be assessed by blinded independent central review in pts with and without ESR1 mutations in the intent-to-treat population. Secondary endpoints include overall survival, antitumor activity (objective response rate, clinical benefit rate, and duration of response), safety, patient-reported outcomes, and PK in pts with and without ESR1 mutations. The study is planned to be conducted globally. Citation Format: Arlene Chan, Jane Meisel, Komal Jhaveri, Joo Hyuk Sohn, Meritxell Bellet- Ezquerra, Jason Schroeder, Mark Shilkrut, Barbara Pistilli. OPERA-01: A randomized, open-label, phase 3, study of palazestrant (OP-1250) vs standard-of-care treatment for ER+, HER2- advanced or metastatic breast cancer after endocrine and CDK4/6 inhibitor therapy [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 PO3-18-09.

Abstract PO3-27-12: Dexamethasone is necessary for preventing acute emesis induced by anthracycline/cyclophosphamide chemotherapy (HELEN-009) : a multicenter, randomized, open-labeled phase 3 trial

Abstract Background Olanzapine, in combination with NK1 receptor antagonist (RA), 5-hydroxytryptamine-3 (5-HT3) RA, and dexamethasone, is now the standard approach to prevent chemotherapy-induced nausea and vomiting (CINV). In this study, we assessed the preventive effect of removing dexamethasone from the quadruple standard antiemetic regimen on CINV caused by anthracycline/cyclophosphamide chemotherapy. Methods The HELEN-009 was a multicenter, randomized, open-labeled phase 3 trial to evaluate the efficacy of NK1RA,5-HT3RA and Olanzapine triplet-combination antiemetic therapy done in 3 hospitals in China.Key inclusion criteria were patients with early breast cancer who were scheduled to be treated with epirubicin plus cyclophosphamide chemotherapy for the first time, age between 18 and 75 years, and with Eastern Cooperative Oncology Group performance status of 0–1. Eligible patients were randomly assigned (1:1) to receive either fosaprepitant, tropisetron, dexamethasone and olanzapine(quadruple group)or fosaprepitant, tropisetron and olanzapine without dexamethasone(triple group). Patients were randomly assigned to interventions by use of a web entry system and the minimization method with a random component, with age as factors of allocation adjustment. The primary endpoint was the proportion of patients who achieved a complete response, defined as absence of vomiting and no use of rescue medications in the overall phase (days 1–5) after starting chemotherapy. All randomly assigned patients who satisfied eligibility criteria received epirubicin plus cyclophosphamide chemotherapy were included in efficacy analysis. All patients who received any treatment in this study were assessed for safety. This study is registered at Clinical Trials Registry, number NCT05242874. Findings Between January 2022 and July 2023, 439 patients with breast cancer were enrolled in the study, with 218 participants randomly assigned to quadruple group and 221 participants assigned to triple group. All eligible patients were observed 120 h after epirubicin plus cyclophosphamide chemotherapy initiation. One patient in the quadruple group withdrew consent. One patient in the quadruple group and one in triple group discontinued treatment on day 1 and was excluded from the efficacy analysis. In the overall phase, the proportion of patients who achieved a complete response was 180 (83.3% [95% CI 78.3–88.3] of 216 patients in the quadruple group and 137 (62.4% [55.8–68.7] of 220 patients in the triple group (p&amp;lt; 0·0001). No grade 3 or higher treatment-related adverse events occurred in either of the groups. Interpretation Dexamethasone remains essential in preventing acute emesis in patients receiving epirubicin plus cyclophosphamide chemotherapy. Table. Proportion of patients in the efficacy analysis set achieving a complete response Table. Treatment-related adverse events with an incidence ≥ 2% Citation Format: Xiuchun Chen, Jiao Dechuang, Chongjian Zhang, Xianfu Sun, Zhenduo Lu, Lianfang Li, Jianghua Qiao, Chengzheng Wang, Min Yan, Yueqing Feng, Ya Wei, Zhenzhen Liu. Dexamethasone is necessary for preventing acute emesis induced by anthracycline/cyclophosphamide chemotherapy (HELEN-009) : a multicenter, randomized, open-labeled phase 3 trial [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 PO3-27-12.

Abstract PO1-28-07: Neoadjuvant docetaxel plus cisplatin versus docetaxel plus doxorubicin and cyclophosphamide in early-stage triple-negative breast cancer (HNBC-001): results from a multicenter, randomized controlled, open-label phase II trial

Abstract Background: Adding platinum to anthracycline- and taxane-based neoadjuvant chemotherapy has improved pathological complete response (pCR) in patients with triple-negative breast cancer (TNBC). However, the efficacy of combining docetaxel and platinum without anthracycline remains controversial. Methods: The HNBC-001 trial was a randomized, phase 2 controlled, and open-label investigation carried out in China at 6 hospitals. The participants who were aged 18–70 years, were histologically confirmed for TNBC clinical stage II–III, suitable for potentially curative surgery, and had an Eastern Cooperative Oncology Group performance status (ECOG-PS) of 0 or 1 were selected for this trial. Participants were randomly categorized into two equal groups; those who received docetaxel plus cisplatin (75 mg/m2, respectively) and those who received docetaxel plus doxorubicin and cyclophosphamide (docetaxel 75 mg/m2, doxorubicin 50 mg/m2, and cyclophosphamide 500 mg/m2). These regimens were given every 3 weeks for 6 cycles. Randomization was stratified by tumor size and nodal status. The primary endpoint was the number of individuals achieving a pCR (ypT0/is ypN0). The trial was registered with chictr.org (number ChiCTR-1800019501). Results: Between November 28, 2018, and June 11, 2022, 212 patients were selected (n=106/treatment). The number of individuals who achieved pCR after docetaxel plus cisplatin treatment was 51.9%, and that of those who attained pCR after docetaxel plus doxorubicin and cyclophosphamide was 35.8% (P=0.019). After 21 months of median follow-up [interquartile range (IQR), 13 to 33], 11 of 106 patients (10.4%) in the docetaxel plus cisplatin group and 14 of 106 patients (13.2%) in the docetaxel plus doxorubicin and cyclophosphamide group had event-free survival (EFS) events [95% confidence interval (CI) =0.360 to 1.783, hazard ratio (HR) =0.801, P=0.585]. The incidence of grade 3 or 4 events was similar in both groups [57 (54%) vs. 51 (48%)]. However, no treatment-associated deaths were identified. Conclusions: In stage II to III TNBC, the docetaxel plus cisplatin regimen achieved higher pCR rates than docetaxel plus doxorubicin and cyclophosphamide, with a manageable toxicity profile. Consistent with the literature, the docetaxel plus cisplatin regimen demonstrated a favorable risk-to-benefit profile and could serve as an optimal neoadjuvant chemotherapy option for patients with high-risk TNBC. table 1: Patient characteristics figure 1: Study endpoints Error bars denote 95% CIs based on normal approximation. p values were calculated from the Chi-square test. (A) Frequency of patients who achieved a pathological complete response per treatment group (primary endpoint). (B) Frequency of patients who achieved a clinical breast tumour response per treatment group, assessed by serial MRI scans after completion of neoadjuvant treatment. (C) Frequency of patients who achieved a minimal residual disease (residual cancer burden class 0 or 1). (D) Frequency of patients who received breast-conservation surgery. table 2: Treatment-emergent adverse events Citation Format: Dechuang Jiao, Jianghua Qiao, Chengzheng Wang, Juntao Li, Xianfu Sun, Zhenduo Lu, Chongjian Zhang, Lianfang Li, Min Yan, Yueqing Feng, Yong Zhou, Miao Deng, Xinlan Liu, Mingde Ma, Haiquan Jia, Qingxin Xia, Xiuchun Chen, Zhenzhen Liu. Neoadjuvant docetaxel plus cisplatin versus docetaxel plus doxorubicin and cyclophosphamide in early-stage triple-negative breast cancer (HNBC-001): results from a multicenter, randomized controlled, open-label phase II trial [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 PO1-28-07.

Abstract PO1-19-11: Phase 3 Study of Tucatinib or Placebo in Combination With Trastuzumab and Pertuzumab as Maintenance Therapy for HER2+ Metastatic Breast Cancer (HER2CLIMB-05, Trial in Progress)

Abstract Background The current first-line (1L) standard of care (SOC) for human epidermal growth factor receptor 2-positive (HER2+) metastatic breast cancer (MBC) is trastuzumab (T) plus pertuzumab (P) and a taxane. Despite advances in 1L SOC, most patients progress during maintenance therapy with T+P. Tucatinib is a tyrosine kinase inhibitor (TKI) approved in combination with T and capecitabine for adults with HER2+ MBC, with and without brain metastases (BM). In HER2CLIMB, addition of tucatinib significantly prolonged progression-free survival (PFS) and overall survival (OS) in patients with HER2+ MBC and was well tolerated. Adding tucatinib also reduced the risk of disease progression or death in patients with untreated and/or active BM (Murthy et al. NEJM 2020, Curigliano et al. Ann Oncol 2022). HER2CLIMB-05 investigates whether adding tucatinib to 1L SOC as maintenance therapy will extend PFS while maintaining quality of life (QOL). Methods HER2CLIMB-05 (NCT05132582) is a phase 3, randomized, double-blind study evaluating tucatinib plus T+P as maintenance therapy for HER2+ MBC. Approximately 650 patients will be enrolled. Eligible patients will have advanced HER2+ disease, no progression on 4–8 cycles of prior 1L SOC, Eastern Cooperative Oncology Group Performance Status of 0 or 1, and no or asymptomatic BM. Exclusion criteria include prior treatment with anti-HER2 and/or anti-epidermal growth factor receptor TKI (prior SOC for early BC is permitted) or inability to undergo contrast magnetic resonance imaging of the brain. Patients will be randomized 1:1 to receive either tucatinib or placebo twice daily, with T+P once every 21 days. Patients with hormone receptor-positive disease may receive endocrine therapy. The primary endpoint is investigator-assessed PFS. Secondary endpoints include OS, time to deterioration of health-related QOL, central nervous system PFS, safety, and pharmacokinetic (PK) parameters. PFS and OS will be compared using a two-sided stratified log-rank test between treatment groups. Time-to-event endpoints will be summarized using the Kaplan–Meier method. PK and safety data will be summarized using descriptive statistics. Enrollment is ongoing in Austria, Chile, Greece, Italy, Japan, Poland, Portugal, Spain, the US, and several other European, APAC, and LATAM countries. This abstract was previously presented at ESMO-BC 2022, FPN (Final Publication Number): 415, by Veronique Dieras (reused with permission). Citation Format: Erika Hamilton, Junji Tsurutani, Giuseppe Curigliano, Miguel Martín, Ciara O'Sullivan, Joo Hyuk Sohn, Konstantinos Tryfonidis, Libero Santarpia, Shan Yang, Véronique Diéras. Phase 3 Study of Tucatinib or Placebo in Combination With Trastuzumab and Pertuzumab as Maintenance Therapy for HER2+ Metastatic Breast Cancer (HER2CLIMB-05, Trial in Progress) [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 PO1-19-11.

Abstract PO1-20-06: Phase 2 study of novel HER2-targeting, TLR7/8 immune-stimulating antibody conjugate (ISAC) BDC-1001 +/- pertuzumab in patients with HER2-positive metastatic breast cancer (MBC) previously treated with trastuzumab deruxtecan

Abstract Background: Therapies to effectively manage patients (pts) with metastatic HER2+ breast cancer have significantly improved over the years, but improvement is still needed in both efficacy and tolerability. BDC-1001 is an ISAC consisting of a trastuzumab biosimilar conjugated to a proprietary cell membrane impermeable TLR7/8 agonist via a non-cleavable linker, administered IV every 2 weeks. It is designed to trigger the innate immune system and generate a durable tumor-targeted adaptive immune response. Preclinical studies indicate that HER2-targeted ISACs elicit potent and durable immune-mediated antitumor efficacy, leading to complete tumor regression in a TLR- and Fc receptor-dependent manner [1]. Moreover, preclinical studies with a murine surrogate of BDC-1001 (trastuzumab-T785 ISAC) indicate improved anti-tumor activity with trastuzumab-T785 compared with trastuzumab/pertuzumab. In these preclinical studies, the combination of trastuzumab-T785 and pertuzumab demonstrated significantly enhanced efficacy in multiple HER2-expressing tumor models, including those with lower HER2 expression [1]. The addition of pertuzumab decreased the quantity of ISAC required for anti-tumor activity in the JIMT-1 HER2 IHC2+ model. Moreover, the combination of pertuzumab with the ISAC significantly increased the cytokine and chemokine concentrations in the tumor xenografts, compared with monotherapy or trastuzumab/pertuzumab, indicating enhanced myeloid activation in the tumor. These preclinical studies suggest that this combination may enhance the clinical activity of trastuzumab-based ISACs. The completed part of the BDC-1001 dose escalation trial (NCT04278144) demonstrated safety, PK and pharmacodynamic changes compatible with the ISAC mechanism of action, and a wide range of antitumor activity (incl. cases with breast cancer); resulting in a RP2D of 20 mg/kg q2w [2]. Two trials are underway, including a Phase 2 trial in other HER2+ malignancies, and a randomized Phase 2 trial with BDC-1001 alone and in combination with pertuzumab in patients with HER2-positive MBC previously treated with 2 or more prior anti-HER2 therapies, including trastuzumab deruxtecan. Methods: The Phase 2 multicenter, open-label, randomized study (BBI-20231001) is enrolling up to 66 pts with HER2-positive (ASCO/CAP guidelines 2018) MBC previously treated with 2 or more prior anti-HER2 therapies, including trastuzumab deruxtecan as one of the prior therapies. Pts must be 18 years or older, have measurable disease (RECIST v1.1), and have Eastern Cooperative Oncology Group performance status of 0 or 1. Pts will be administered BDC-1001 20 mg/kg every 2 weeks (IV q2w) and randomized 1:1 to receive BDC-1001 as a single agent or in combination with pertuzumab. The trial has a Simon 2-stage design within each arm. The primary objective is to determine the overall response rate per RECIST v1.1 of BDC-1001 alone and in combination with pertuzumab. Secondary objectives will evaluate safety, additional efficacy parameters, pharmacokinetics, and immunogenicity of BDC-1001 alone and in combination with pertuzumab. Exploratory objectives will include pharmacodynamic biomarkers in tumor tissue (baseline and on-treatment biopsies if feasible) and in peripheral blood to elucidate the mechanism of action and seek to identify biomarkers associated with BDC-1001 biological activity with or without pertuzumab. This study is expected to initiate accrual in 2H 2023. For additional information, please contact Bolt Biotherapeutics at 1-650-665-9295 or info@boltbio.com.

Abstract PO4-12-10: Sacituzumab Govitecan Toxicity Outcomes In Arab Patients with Metastatic Breast Cancer

Abstract Background: The Arab population is often underrepresented in clinical trials, which limits our knowledge of drug safety and efficacy in this population due to genetic variability that can affect drug metabolism and adverse events (AEs). Sacituzumab govitecan (SG) is approved for metastatic triple negative breast cancer (mTNBC), and recently hormone receptor positive metastatic breast cancer (HR+ MBC). Here we report toxicity outcomes and RDI in Arab population. Methods: A multi-center retrospective study of patients with mTNBC and HR+ MBC treated with SG from January 2021 until May 2023 was conducted. Demographics and clinical variables including site of metastases, prior lines of therapy, relative dose intensity (RDI), adverse events (AEs) were collected. For continuous variables, Mann-U Whitney and Kruskal Wallis tests were used to compare mean, median, standard deviation, and range. For categorical variables, Fisher's exact tests and Pearson Chi-square tests were used. SAS v9.4 was used to perform statistical analysis at a significance level of 0.05. Results: A total of 35 patients was enrolled. The median age at diagnosis of metastatic breast cancer was 39 years interquartile range (IQR) (35, 44). The median age at starting SG was 44.5 years IQR (38,50). The majority of patients (65%) had an Eastern Cooperative Oncology Group performance status (ECOG PS) of 1, (21%) of the patients had an ECOG PS of 0, and (15%) had an ECOG PS of 2. 48.6% received 3 or more lines of prior therapy in the metastatic setting while 51.4% received less than 3 lines of prior therapy in the metastatic setting. 77.1% of patients had 3 or &amp;gt; organs involved with metastatic disease, while 22.9% of patients had &amp;lt; 3 organ involved. The most common metastatic sites were the lung (54.3%), liver (62.9%), bone (68.6%), and brain (45.7%). The median RDI of SG was 100% for a sample of 34 individuals, with one missing value IQR (94%,100%). The rate of overall AEs was (77.1%), with the most common AEs being; neutropenia (44.4%), diarrhea (37.0%), anemia (22.2%), thrombocytopenia (22.2%), nausea (14.8%), and vomiting (7.4%). Garde 3 AEs rate was 34.3%. The most common grade 3 adverse events were diarrhea (11.4%), fatigue (5.7%), and alopecia (2.9%). The rate of treatment interruption and dose reduction due to AEs was 31.4%. Only one patient (2.9%) had to discontinue SG treatment due to adverse events. Conclusion: The study suggests that SG is safe and well-tolerated in young Arab patient population. The sample consisted of relatively young patients, which may reflect a reluctance to prescribe SG to older Arab patients. Caution should be exercised when generalizing the findings due to limitations of the study. Further studies with larger sample sizes are needed to validate these findings and to explore the efficacy of SG in Arab patients with mTNBC and HR+ MBC. Citation Format: Maymouna Altarturi, Kausar Suleman, Adhar AlSayed, Humaid Al-Shamsi, Aydah Alawadhi, Bassam Basuliamn, Sabah Alaklabi. Sacituzumab Govitecan Toxicity Outcomes In Arab Patients with Metastatic 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 PO4-12-10.

Abstract PO4-18-04: An exploratory study of Trastuzumab Deruxtecan neoadjuvant therapy in HER2-positive or HER2-low early or locally advanced breast cancer after a poor response to neoadjuvant chemotherapy

Abstract Background The current standard of care for neoadjuvant treatment of HER2-positive early-stage breast cancer consists of dual HER2-blockade with trastuzumab (H) plus pertuzumab (P) and polychemotherapy with a pathological complete response (pCR) rate of 31%~50%. Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate composed of an anti-HER2 antibody, a cleavable tetrapeptide-based linker, and a cytotoxic topoisomerase I inhibitor. T-DXd significantly prolonged progression-free and overall survival vs trastuzumab emtansine in HER2-positive unresectable and/or metastatic breast cancer (mBC) previously treated with H and taxane in DESTINY-Breast03 study. HER2-low breast cancer is currently treated as HER2-negative (HER2-low and HER2-zero) breast cancer, with patients stratified according to hormone-receptor (HR) status. In DESTINY-Breast04 study, T-DXd resulted in significantly longer progression-free and overall survival than the physician’s choice of chemotherapy in HER2-low mBC. Given the efficacy of T-DXd monotherapy in HER2-positive or HER2-low mBC, we conduct an exploratory study to evaluate the efficacy and safety of T-DXd in HER2-positive or HER2-low early or locally advanced breast cancer after a poor response to neoadjuvant chemotherapy, and to identify sensitive biomarkers for T-DXd neoadjuvant therapy. Methods Eligible patients were women aged 18 years to 75 years with clinical stage cT2–cT4/cN0–cN3/cM0 (stage II–III) invasive breast cancer (&amp;gt;2 cm in size) confirmed as HER2-positive (immunohistochemistry [IHC] 3+) or HER2-low (IHC2+ or IHC1+/situ hybridization-negative). Patients are required to have an Eastern Cooperative Oncology Group performance status of 0 or 1, and baseline left ventricular ejection fraction of at least 55% (as measured by echocardiogram). Patients are also required to have adequate organ function and bone marrow function. Patients with HER2-positive breast cancer should receive taxane (paclitaxel or nab-paclitaxel) or docetaxel, carboplatin, and H plus P for 2 cycles. Patients with HER2-low and HR-positive breast cancer should receive taxane (paclitaxel or nab-paclitaxel) or docetaxel, and cisplatin or carboplatin for 2 cycles. Patients with HER2-low and HR-negative breast cancer should receive taxane (paclitaxel or nab-paclitaxel) or docetaxel, and anthracycline (epirubicin, pirarubicin or liposomal doxorubicin) for 2 cycles. For patients who have responses of stable disease assessed by magnetic resonance imaging will receive T-DXd neoadjuvant therapy. T-DXd will be administered intravenously every 3 weeks at a dose of 5.4 mg per kilogram of body weight for 4 cycles. Peripheral blood and biopsy tissue will be collected before neoadjuvant chemotherapy and T-DXd neoadjuvant therapy, and peripheral blood and surgical tissue will be collected after the surgery. Lipid metabolites in peripheral blood and mass spectrometry-based protein quantification in tissue will be detected to find sensitive biomarkers for T-DXd neoadjuvant therapy. The primary endpoint is pCR rate (ypT0/Tis ypN0) and identify sensitive biomarkers for T-DXd neoadjuvant therapy. Secondary endpoints include objective response rate, breast-conserving rate and invasive disease-free survival. Citation Format: Jin Zhang, Zhendong Shi, Jingjing Liu. An exploratory study of Trastuzumab Deruxtecan neoadjuvant therapy in HER2-positive or HER2-low early or locally advanced breast cancer after a poor response to neoadjuvant chemotherapy [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 PO4-18-04.