Treatment Of Physician's Choice Research Articles

Abstract PO5-21-09: Clinical outcomes by age subgroups in the phase 3 TROPiCS-02 study of sacituzumab govitecan vs treatment of physician’s choice in HR+/HER2‒ metastatic breast cancer

Abstract Background Sacituzumab govitecan (SG) is a Trop-2directed antibody-drug conjugate approved for second-line or later (2L+) treatment of metastatic triple-negative breast cancer in multiple countries and for 2L+ treatment of HR+/HER2‒ (IHC 0, 1+, or 2+/ISH) metastatic breast cancer (mBC) in the US. SG significantly improved progression-free survival (PFS) and overall survival (OS) vs treatment of physician’s choice (TPC) in patients (pts) with pretreated, endocrine-resistant HR+/HER2‒ mBC in the TROPiCS-02 study. The incidence of HR+/HER2‒ mBC increases with age, especially after 65, and older pts often have poorer prognosis due to comorbidities, increased toxicity, and reduced efficacy of chemotherapy. In TROPiCS-02, pts aged ≥ 65 years (yr) derived consistent PFS benefit and clinically meaningful improved OS with SG vs TPC. In this analysis, we present additional efficacy and safety outcomes by age subgroup. Methods Pts with HR+/HER2‒ mBC who had received at least 1 endocrine therapy, taxane, and CDK4/6 inhibitor, and 2 to 4 prior lines of chemotherapy for mBC, were randomized to either SG (10 mg/kg IV days 1 and 8, Q3W) or TPC. The primary end point was PFS, and secondary end points included OS, objective response rate (ORR), and safety. A post hoc analysis was conducted by age subgroups (< 65 vs ≥ 65, < 75 vs ≥ 75). Results In total, 543 pts were randomized to the SG (n = 272; 73 [27%] ≥ 65, 16 [6%] ≥ 75) and TPC (n = 271; 67 [25%] ≥ 65, 8 [3%] ≥ 75) groups. Baseline characteristics were generally similar across treatment arms in each age subgroup, but a higher proportion of pts had performance status 1 vs 0 in the ≥ 65 vs < 65 and ≥ 75 vs < 75 subgroups, respectively. The data cutoff date was July 1, 2022. SG demonstrated longer median PFS and OS vs TPC across age subgroups. Hazard ratios (HR) for PFS with SG vs TPC were 0.69, 0.59, 0.70, and 0.30 for the < 65, ≥ 65, < 75, and ≥ 75 subgroups, respectively (Table). The HR for OS were 0.81, 0.80, 0.82, and 0.56 in these subgroups, respectively (Table). Median duration of response (DoR) was also longer with SG vs TPC across age subgroups, although median DoR was not estimable in the ≥ 75 subgroup (Table). ORR was higher with SG vs TPC, except in the ≥ 75 subgroup (Table). Safety was generally similar with SG vs TPC across subgroups with the following differences. Grade ≥ 3 treatment-emergent adverse events were more common in the ≥ 75 subgroup than the other subgroups (SG, 81% in ≥ 75 vs 68%-73% for all others; TPC, 71% in ≥ 75 vs 60%-61% for all others). TEAEs leading to dose reduction were also more common in pts treated with SG in the ≥ 75 subgroup, but were consistent across other subgroups (Table). However, sample sizes in the ≥ 75 subgroup were small, which limits interpretation (Table). TEAEs leading to treatment discontinuation were more common in older pts, irrespective of treatment group (Table). Conclusions SG showed benefit in PFS and OS vs TPC in pts with HR+/HER2‒ mBC across age subgroups, consistent with the intent to treat population. SG was associated with a slight increase in toxicity for elderly pts, as expected. SG demonstrated a favorable benefit/risk profile, with efficacy benefit and acceptable toxicity, for elderly pts. Table. Citation Format: Aditya Bardia, Peter Schmid, Sara Tolaney, Frederik Marmé, Javier Cortés, Theresa Valdez, Hao Wang, Wendy Verret, Hope Rugo. Clinical outcomes by age subgroups in the phase 3 TROPiCS-02 study of sacituzumab govitecan vs treatment of physician’s choice in HR+/HER2‒ 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 PO5-21-09.

Abstract PO1-06-01: Clinical Efficacy of Tumor Organoid-Guided Cancer Therapy for Locally Advanced Unresectable or Metastatic Breast Cancer

Abstract Purpose: Patient-derived organoids (PDOs) may facilitate treatment selection, but the feasibility of using breast cancer PDOs to guide personalized treatment in clinical practice has not been fully investigated. This study aimed to assess the clinical efficacy of treatment guided by PDO drug sensitivity tests (OGT) versus treatment of physician’s choice (TPC) in patients with locally advanced unresectable or metastatic breast cancer (MBC) and to explore the potential of PDOs to reveal mechanisms underlying treatment resistance. Methods: Patients diagnosed with MBC were recruited between January 2020 and August 2022. PDOs were established from biopsies specimens or malignant effusion samples. The efficacy of customized drug panels was determined by measuring cell mortality after drug exposure. Patients receiving OGT were matched 1:2 by nearest neighbor propensity scores with patients receiving TPC. The primary clinical outcome was progression-free survival. Secondary outcomes included objective response rate and disease control rate. Targeted gene sequencing and pathway enrichment analysis were performed. Results: 46 PDOs (46 of 51, 90.2%) were generated from 45 MBC patients. PDO drug screening showed an accuracy of 81.1% (95% CI 67.6%-91.9%) in predicting patients' clinical responses. 36 OGT patients were matched to 69 TPC patients. OGT was associated with prolonged median progression-free survival (11.0 months vs 5.0 months; unadjusted hazard ratio 0.53 [95% CI 0.33-0.85]; P=0.01) and improved disease control (88.9% vs 63.8%; unadjusted odd ratio 4.26 [1.44-18.62]) compared with TPC. The objective response rate of both groups was similar. Pathway enrichment analysis uncovered differentially modulated pathways implicated in DNA repair and transcriptional regulation in patients less sensitive to capecitabine/gemcitabine, and pathways associated with cell cycle regulation in patients less sensitive to palbociclib. Conclusions: MBC patients treated with OGT were associated with superior progression-free survival and disease control compared with TPC. PDO-based functional precision medicine is a feasible strategy for treatment optimization and customization in MBC and may enhance our understanding of therapeutic resistance. Citation Format: Ying-Yi Lin, Hong-Fei Gao, Hong Li, Bo-Lei Du, Min-Yi Cheng, Jia-Chen Zou, Xing-xing Zheng, Teng Zhu, Ting-Ting Li, Sheng Li, Kun Wang. Clinical Efficacy of Tumor Organoid-Guided Cancer Therapy for Locally Advanced Unresectable or 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 PO1-06-01.

Abstract PO1-05-09: ASCENT-07: A phase 3, randomized, open-label study of sacituzumab govitecan versus treatment of physician’s choice in patients with HR+/HER2– inoperable, locally advanced, or metastatic breast cancer post-endocrine therapy

Abstract Background: Approximately 70% of all breast cancer (BC) cases are hormone receptor positive/human epidermal growth factor receptor 2-negative (HR+/HER2–), with ~65% of these being HR+/HER2-low (immunohistochemistry [IHC]1+, IHC2+/in situ hybridization [ISH]–). Despite an increasing number of available endocrine and targeted treatments for metastatic disease, tumors eventually develop resistance to endocrine therapy (ET). Chemotherapy, the standard of care for patients (pts) whose cancers no longer respond to ET, is associated with poor outcomes, representing a high unmet need in the first-line endocrine-resistant setting. Sacituzumab govitecan (SG) is a Trop-2–directed antibody-drug conjugate (ADC) that delivers SN-38 (the active metabolite of the topoisomerase inhibitor irinotecan) to tumor cells via internalization, and to the surrounding tumor microenvironment via the bystander effect. SG demonstrated a significant and clinically meaningful survival benefit in the phase 3, randomized TROPiCS-02 trial, and is approved in the US for inoperable, locally advanced, or metastatic HR+/HER2– BC after ET and ≥ 2 systemic therapies in the metastatic setting. ASCENT-07 will examine the efficacy and safety of SG in the first-line chemotherapy setting, ie, in patients with inoperable, locally advanced, or metastatic ET resistant HR+/HER2– BC. Study design: ASCENT-07 (NCT05840211) is a randomized, open-label, global study evaluating SG versus treatment of physician’s choice (TPC) chemotherapy in pts with HR+/HER2– inoperable, locally advanced, or metastatic BC who have received ET and are eligible for their first chemotherapy for advanced/metastatic disease. Pts aged ≥ 18 years with histologically confirmed HR+/HER2– (HER2 IHC0 or HER2-low [IHC1+, IHC2+/ISH–]) according to ASCO/CAP criteria, measurable disease per RECIST v1.1, and ECOG performance status of 0 or 1 will be included. Pts are eligible if they meet ≥ 1 of the following criteria: progressive disease (PD) in the metastatic setting on ≥ 2 lines of ET (± targeted therapy) (disease recurrence within the first 24 months of starting adjuvant ET is considered a line of therapy), PD within 6 months of first-line ET (± CDK 4/6 inhibitor) in the metastatic setting, or disease recurrence within 24 months of adjuvant ET with CDK 4/6 inhibitor initiation and no longer a candidate for additional ET. PD on the most recent therapy will be documented by CT or MRI per RECIST v1.1. Key exclusion criteria include prior treatment targeting topoisomerase I. Pts will be randomized to SG 10 mg/kg IV on days 1 and 8 of a 21-day cycle or TPC (capecitabine, paclitaxel, nab-paclitaxel). The primary endpoint is progression-free survival (PFS) assessed by blinded independent central review (BICR) per RECIST v1.1 criteria or death from any cause, whichever comes first. Secondary endpoints include PFS (assessed by the investigator), overall survival, objective response rate and duration of response per BICR and investigator, and quality of life (QoL) assessed using the EORTC QLQ-C30 cancer questionnaire (primarily change in the Physical Functioning domain at week 16 and time to deterioration in the Global Health Status/QoL domain). Pharmacokinetics and immunogenicity analyses will be undertaken in pts receiving SG. Incidence of adverse events and serious adverse events, including relationship to study drug(s), will be reported. Laboratory and vital signs will be monitored. ASCENT-07 is currently open for recruitment and requires ~654 eligible pts to provide adequate power for assessment of the primary and key secondary endpoints. Citation Format: Hope Rugo, Javier Cortés, Giuseppe Curigliano, Carlos Barrios, Kevin Punie, Yeon Park, Hiroji Iwata, Alex Young, Xuehan Ren, Pelin Cinar, Komal Jhaveri. ASCENT-07: A phase 3, randomized, open-label study of sacituzumab govitecan versus treatment of physician’s choice in patients with HR+/HER2– inoperable, locally advanced, or metastatic breast cancer post-endocrine 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 PO1-05-09.

Abstract PO1-06-10: Overall survival results from EVER-132-001, a phase 2b single-arm study of sacituzumab govitecan in Chinese patients with metastatic triple-negative breast cancer

Abstract Background Breast cancer is the most frequently diagnosed cancer and the 5th most common cause of cancer-related death in Chinese women with over 416,000 new cases and over 117,000 deaths estimated in 2020. Triple-negative breast cancer (TNBC) represents 10%-20% of cases in women with breast cancer. Sacituzumab govitecan (SG) is a Trop-2-directed antibody-drug conjugate and is approved for second-line or later (2L+) treatment of metastatic (m)TNBC in multiple countries, including the US and China. In the pivotal phase 3 study ASCENT, which enrolled predominantly non-Asian patients (pts), SG demonstrated improved efficacy outcomes vs treatment of physician’s choice (TPC) in pts with mTNBC treated in 2L+, with a manageable safety profile. For pts treated with SG, median progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) were improved vs TPC (Bardia A et al, 2021). The single-arm phase 2b EVER-132-001 study was conducted to assess the efficacy and safety of 2L+ SG in Chinese pts with mTNBC. In preliminary findings from EVER-132-001, SG demonstrated substantial clinical activity and a manageable safety profile (Xu B et al, 2023). Here, we present additional efficacy and safety results from EVER-132-001, including the first report of median OS. Methods Pts with mTNBC who had received at least 2 prior lines of chemotherapy for mTNBC received SG (10 mg/kg IV on days 1 and 8, Q3W). The primary end point was ORR per independent review committee (IRC). Secondary end points included duration of response (DoR) per IRC, clinical benefit rate (CBR) per IRC, PFS per IRC, OS, and safety. Results Eighty pts were enrolled, with a median age of 48 years (range 24-70). Pts had received a median of 4 prior treatment regimens (range 2-8), and 59% of pts had ECOG performance status of 1. At the data cutoff, September 19, 2022, with a median follow-up of 14.7 mo (range 1.2-25.3), median OS was 14.7 mo (95% CI 10.3-18.3) and the OS rate at 12 months was 54% (95% CI 42-64) (Table). ORR was 40% (95% CI 29-52) with median DoR of 11.6 mo (95% CI 7.0-13.8), and CBR was 46% (95% CI 35-58) (Table). Median PFS was 5.6 mo (95% CI 4.1-8.3) (Table). Grade ≥ 3 treatment-emergent adverse events (TEAEs) occurred in 79% of pts, and TEAEs leading to dose reduction, treatment interruption, and treatment discontinuation occurred in 20%, 48%, and 8% of patients, respectively (Table). The most common TEAEs of any grade were decreased neutrophil count (85%), anemia (84%), and decreased white blood cell count (83%). The most common grade ≥ 3 TEAEs were decreased neutrophil count (64%), decreased white blood cell count (50%), and anemia (23%). Conclusions SG continued to demonstrate substantial clinical activity, with OS, ORR, DoR, CBR, and PFS results in the EVER-132-001 trial, consistent with the phase 3 ASCENT trial of SG in mTNBC. TEAEs were manageable and no new safety signals were identified. These results support the use of SG as a new standard of care for Chinese pts with pretreated mTNBC. Table Citation Format: Fei Ma, Shusen Wang, Zhongsheng Tong, Wei Li, Xinhong Wu, Xiaojia Wang, Tao Sun, Yueyin Pan, Herui Yao, Xian Wang, Ting Luo, Jin Yang, Xiaohua Zeng, Weihong Zhao, Kimberly Komatsubara, Rachel Nakamura, Catherine Lai, Bo Zhang, Xiuyu Cong, Binghe Xu. Overall survival results from EVER-132-001, a phase 2b single-arm study of sacituzumab govitecan in Chinese patients with metastatic triple-negative 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 PO1-06-10.

Subgroup analyses from the phase 3 ASCENT study of sacituzumab govitecan in metastatic triple-negative breast cancer

In this post hoc analysis of the ASCENT study, we compared outcomes with sacituzumab govitecan (SG) vs single-agent chemotherapy in clinically important subgroups of patients with metastatic triple-negative breast cancer (mTNBC). Patients with mTNBC refractory to/relapsing after ≥2 prior chemotherapies (≥1 in the metastatic setting) were randomized 1:1 to receive SG or treatment of physician’s choice (TPC) until unacceptable toxicity/progression. The primary endpoint was progression-free survival (PFS) per RECIST 1.1 by central review in patients without brain metastases. Patients with brain metastases were allowed if metastases were stable ≥4 weeks. In the intention-to-treat (ITT) population, 19% of patients were age ≥65 years; 12% were Black, and 12% had brain metastases. SG improved PFS and overall survival (OS), respectively, vs TPC in patients age ≥65 years (7.1 vs 2.4 months and 14.7 vs 8.9 months), or of Black race (5.4 vs 2.2 months and 13.8 vs 8.5 months), consistent with outcomes in the ITT population. Patients with brain metastases had numerically higher median PFS with SG vs TPC, but median OS was similar between treatment groups. SG was well tolerated and had a manageable safety profile consistent with the full safety population across all subgroups; neutropenia and diarrhea were the most common treatment-emergent adverse events. These findings confirm the meaningful clinical benefit of SG vs standard chemotherapy in patient subgroups with high unmet needs. SG should be considered an effective and safe treatment option for patients with mTNBC eligible for second-line or later therapy. ClinicalTrials.gov Number: NCT02574455.

Cost-effectiveness of sacituzumab govitecan versus single-agent chemotherapy for metastatic triple-negative breast cancer: a trial-based analysis

BackgroundSacituzumab govitecan (SG) has recently been approved in China for the post-line treatment of metastatic triple-negative breast cancer (mTNBC). SG substantially improves progression-free survival and overall survival compared with single-agent chemotherapy for pretreated mTNBC. However, in view of the high price of SG, it is necessary to consider its value in terms of costs and outcomes. This study aimed to estimate the cost-effectiveness of SG versus single-agent treatment of physician’s choice (TPC) in the post-line setting for patients with mTNBC from a Chinese healthcare system perspective.MethodsThe cohort characteristics were sourced from the ASCENT randomized clinical trial, which enrolled 468 heavily pretreated patients with mTNBC between November 2017 and September 2019. A partitioned survival model was constructed to assess the long-term costs and effectiveness of SG versus TPC in the post-line treatment of mTNBC. Quality-adjusted life-months (QALMs) and total costs in 2022 US dollars were used to derive incremental cost effectiveness ratio (ICER). QALMs and costs were discounted at 5% annually. The willingness-to-pay (WTP) threshold was defined as $3188 per QALM, three times China’s average monthly per capita gross domestic product in 2022. One-way sensitivity analysis, probabilistic sensitivity analysis, and scenario analyses were performed to estimate the robustness of the results.ResultsTreatment with SG yielded an incremental 5.17 QALMs at a cost of $44,792 per QALM, much above the WTP threshold of $3188/QALM in China. One-way sensitivity analysis showed that SG price was a crucial factor in the ICER. Probabilistic sensitivity analysis revealed that the cost-effective acceptability of SG was 0% in the current setting. Scenario analyses indicated that the result was robust in all subgroups in ASCENT or under different time horizons. Furthermore, SG must reduce the price to enter the Chinese mainland market. When the monthly cost of SG reduce to $2298, SG has about 50% probability to be a preferred choice than TPC.ConclusionsSG was estimated to be not cost-effective compared with TPC for post-line treatment for mTNBC in China by the current price in HK under a WTP threshold of $3188 per QALM. A drastic price reduction is necessary to improve its cost-effectiveness.

LBA4 Sacituzumab govitecan (SG) vs treatment of physician’s choice (TPC) in Asian patients with hormone receptor-positive and human epidermal growth factor receptor 2-negative (HR+/HER2–) metastatic breast cancer (mBC): Results from the phase III EVER-002 study

LBA4 Sacituzumab govitecan (SG) vs treatment of physician’s choice (TPC) in Asian patients with hormone receptor-positive and human epidermal growth factor receptor 2-negative (HR+/HER2–) metastatic breast cancer (mBC): Results from the phase III EVER-002 study

Efficacy of oral SERDs in the treatment of ER+, HER2− metastatic breast cancer: a stratified analysis of the ESR1 wild type and mutant subgroups

Oral SERDs are a novel drug class that have been developed to counteract resistance due to ESR1 mutations. Several SERDs have emerged from phase 2 and 3 trials, with the FDA limiting approval for Elacestrant to patients with ESR1mt tumours despite PFS benefit in the overall population. However, questions remain on whether patients with ESR1wt tumours stand to benefit from oral SERDs. Manuscripts and conference presentations of Randomised Controlled Trials were extracted after a systematic search of Embase, PubMed and Cochrane from inception until January 21,2023. RCTs investigating the efficacy of oral SERDs versus endocrine therapy for ER positive, HER2 negative advanced breast cancer, and which reported the Kaplan Meier (KM) curves of PFS in the overall and ESR1 mutant (ESR1mt) population were selected. A graphical reconstructive algorithm was applied to estimate time-to-event outcomes from reported KM curves in all overall and ESR1mt cohorts. A bipartite matching algorithm, KMSubtraction, was used to derive survival data for unreported (ESR1wt) subgroups. An individual patient data (IPD) meta-analysis was then pursued, pooling data by ESR1 mutation status in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Cochrane Guidelines for IPD. The randomized clinical trials ACELERA, AMEERA-3, EMERALD and SERENA-2 were included, totalling 1290 patients. In the pooled analysis of the overall cohort, PFS benefit was observed with oral SERDs when compared with treatment of physicians choice (TPC) (HR 0.783, 95%CI 0.681-0.900, p<0.001). In the ESR1mt subgroup, oral SERDs demonstrated improved PFS (HR 0.557, 95%CI 0.440-0.705, p<0.001) compared to TPC. In the ESR1wt subgroup, oral SERDs demonstrated no significant PFS benefit (HR 0.944, 95%CI 0.783-1.138, p=0.543) when compared to TPC. The results of this IPD meta-analysis suggests that PFS benefit in the overall population is mainly driven by the ESR1mt subgroup.

388P Subgroup analysis of patients (pts) with HER2-low metastatic breast cancer (mBC) with brain metastases (BMs) at baseline from DESTINY-Breast04, a randomized phase III study of trastuzumab deruxtecan (T-DXd) vs treatment of physician’s choice (TPC)

388P Subgroup analysis of patients (pts) with HER2-low metastatic breast cancer (mBC) with brain metastases (BMs) at baseline from DESTINY-Breast04, a randomized phase III study of trastuzumab deruxtecan (T-DXd) vs treatment of physician’s choice (TPC)

376O Trastuzumab deruxtecan (T-DXd) versus treatment of physician’s choice (TPC) in patients (pts) with HER2-low unresectable and/or metastatic breast cancer (mBC): Updated survival results of the randomized, phase III DESTINY-Breast04 study

376O Trastuzumab deruxtecan (T-DXd) versus treatment of physician’s choice (TPC) in patients (pts) with HER2-low unresectable and/or metastatic breast cancer (mBC): Updated survival results of the randomized, phase III DESTINY-Breast04 study

389P Efficacy and safety analyses by prior lines of chemotherapy from the phase III TROPiCS-02 study of sacituzumab govitecan (SG) vs treatment of physician’s choice (TPC) in patients (pts) with HR+/HER2- metastatic breast cancer (mBC)

389P Efficacy and safety analyses by prior lines of chemotherapy from the phase III TROPiCS-02 study of sacituzumab govitecan (SG) vs treatment of physician’s choice (TPC) in patients (pts) with HR+/HER2- metastatic breast cancer (mBC)

Trop-2 mRNA expression and association with clinical outcomes with sacituzumab govitecan (SG) in patients with HR+/HER2– metastatic breast cancer (mBC): Biomarker results from the phase 3 TROPiCS-02 study.

1082 Background: SG is a Trop-2–directed antibody-drug conjugate approved in multiple countries for patients with metastatic triple-negative breast cancer who received at least 1 prior systemic therapy and in the US for patients with pretreated HR+/HER2– mBC. In the TROPiCS-02 study, SG significantly improved progression-free survival (PFS; median, 5.5 vs 4.0 mo; HR, 0.66 [95% CI, 0.53-0.83]; P=0.0003) and overall survival (OS; median, 14.4 vs 11.2 mo; HR, 0.79 [95% CI, 0.53-0.83]; P=0.020) over treatment of physician’s choice (TPC) in patients with pretreated, endocrine-resistant HR+/HER2– mBC. In TROPiCS-02 post hoc analyses, SG improved OS regardless of Trop-2 expression by immunohistochemistry (IHC; Rugo HS, et al. SABCS 2022), but association using more sensitive assays are lacking. Here, we examine efficacy outcomes for SG versus TPC by Trop-2 gene ( TACSTD2) mRNA expression and the correlation of TACSTD2 expression with other genes. Methods: Patients with HR+/HER2– mBC who received ≥1 prior taxane, endocrine therapy and a CDK4/6 inhibitor, and 2-4 prior chemotherapy regimens for mBC were randomized 1:1 to SG or TPC. The primary endpoint was PFS by central review per RECIST v1.1. RNA was isolated from archival tumor tissue samples using AllPrep DNA/RNA kits and libraries prepared with TruSeq RNA Exome Prep Kit. Sequencing was via NovaSeq (2x150bp). Gene expression quantitation was performed using Salmon. TACSTD2 expression was defined as high or low via median cut. Results: In the mRNA analytical cohort (N=197), 49% had TACSTD2 high expression (SG, n=51; TPC, n=46), and 51% had TACSTD2 low expression (SG, n=47; TPC, n=53). Baseline characteristics were generally consistent between TACSTD2 expression subsets and the intention-to-treat population. A positive concordance between TACSTD2expression and Trop-2 IHC (H-score) was observed (categorical concordance 71%; Cohen’s kappa = 0.41). TACSTD2 expression was similar across HER2 IHC0 and HER2-Low subgroups (log2 transcripts per million [TPM] of 3.36 [IQR, 2.76-4.22] and log2TPM of 3.44 [IQR, 2.59-4.22], respectively). SG showed a numerically higher median PFS ( TACSTD2 high, 7.3 vs 5.6 mo; TACSTD2 low, 5.6 vs 2.8 mo) versus TPC regardless of TACSTD2 expression. Similarly, for OS, outcomes favored SG over TPC regardless of TACSTD2 expression. Conclusions: This mRNA-based biomarker analysis demonstrated that SG improves PFS and OS outcomes in patients with pretreated, endocrine-resistant HR+/HER2– mBC regardless of Trop-2 mRNA expression. There was no correlation between Trop-2 mRNA expression and HER2 status. Trop-2 mRNA expression was not predictive of benefit with SG. Additional studies are needed to determine whether Trop-2 mRNA expression has a prognostic role in mBC. Clinical trial information: NCT03901339 .

Trastuzumab deruxtecan (T-DXd) vs treatment of physician’s choice (TPC) in patients (pts) with HER2-low, hormone receptor-positive (HR+) unresectable and/or metastatic breast cancer (mBC): Exploratory biomarker analysis of DESTINY-Breast04.

1020 Background: DESTINY-Breast04 (NCT03734029) showed improved progression-free survival (PFS) and overall survival for T-DXd vs TPC in pts with HER2-low (IHC 1+ or 2+/ISH-negative) mBC. We present exploratory biomarker analysis in pts with HER2-low, HR+ mBC. Methods: Biopsy specimens collected from 326 pts after prior treatment were analyzed using RNA-sequencing and intrinsic subtypes estimated by PAM50 gene expression. ESR1 and PIK3CA mutations and known gene alterations associated with resistance to CDK4/6 inhibitors (CDK4/6i) were assessed in baseline (BL) circulating tumor DNA (ctDNA) samples from 414 pts by Guardant OMNI. Association with objective response rate (ORR) and PFS was evaluated. Results: Frequencies of BL intrinsic subtypes in the T-DXd and TPC arms were 41.3% and 46.6% for Luminal A, 48.0% and 37.9% for Luminal B, and 9.0% and 11.7% for HER2 enriched, respectively. According to ctDNA results in the T-DXd and TPC arms, respectively, ESR1 mutations were observed in 51.3% and 54.0% of pts, PIK3CA mutations in 36.1% and 41.6% of pts, and at least one CDK4/6i resistance marker (pts with prior CDK4/6i) was detected in 71.5% and 70.2% of pts. Improved T-DXd efficacy was seen regardless of intrinsic subtype (Luminal A, Luminal B, HER2-enriched), ESR1 mutation, PIK3CA mutation, or CDK4/6i resistance markers (Table). Conclusions: Greater clinical benefit was consistently observed with T-DXd vs TPC independent of intrinsic subtype, ESR1 mutation, PIK3CA mutation, or known CDK4/6i resistance marker status. Clinical trial information: NCT03734029 . [Table: see text]

Final overall survival (OS) analysis from the phase 3 TROPiCS-02 study of sacituzumab govitecan (SG) in patients (pts) with hormone receptor–positive/HER2-negative (HR+/HER2–) metastatic breast cancer (mBC).

1003 Background: Treatment of HR+/HER2– mBC includes sequential endocrine therapy (ET) combined with targeted agents followed by sequential single-agent chemotherapy (CT), which is associated with poor outcomes and quality of life. SG is a Trop-2–directed antibody-drug conjugate approved in multiple countries for pts with metastatic triple-negative breast cancer who received ≥1 prior systemic therapy and in the US for pts with pretreated HR+/HER2- mBC. In the phase 3 TROPiCS-02 study, SG demonstrated a statistically significant OS benefit versus treatment of physician’s choice (TPC) in pts with pretreated, ET-resistant HR+/HER2– mBC at the 2nd planned interim OS analysis with 390 events (median, 14.4 vs 11.2 mo; HR, 0.79 [95% CI, 0.65-0.96]; P=0.02; Rugo HS, et al. ESMO 2022. LBA76); this is considered the final analysis per the protocol. Here, we report the results of an exploratory analysis of OS from TROPiCS-02 with a longer median follow-up (12.75 mo). Methods: Eligible pts withHR+/HER2– mBC who received prior taxane, ET, CDK4/6 inhibitor, and 2-4 prior lines of CT were randomly assigned 1:1 to receive SG (10 mg/kg IV d1 and 8, every 21 d) or TPC until disease progression or unacceptable toxicity. The primary endpoint was progression-free survival by blinded independent central review per RECIST v1.1. Key secondary endpoints included OS and safety. In an exploratory analysis, we evaluated OS by HER2 immunohistochemistry (IHC). Results: In total, 543 pts (median prior CT for mBC, 3; visceral metastases, 95%) were randomized to receive SG (n=272) or TPC (n=271). At data cutoff (Dec 1, 2022), 437 OS events had occurred (median follow-up, 12.75 mo), with 47 (8.7%) new deaths in the SG versus TPC groups (22 [8.1%] vs 25 [9.2%]) since the 2nd planned interim analysis. With this extended follow-up, SG continues to demonstrate improved OS versus TPC (median, 14.5 vs 11.2 mo; HR, 0.79 [95% CI, 0.65-0.95]; nominal P=0.01). The OS rates (95% CI) for SG versus TPC were 60.9% (54.8-66.4) and 47.1% (41.0-53.0) at 12 months, 39.2% (33.4-45.0) and 31.7% (26.2-37.4) at 18 months, and 25.6% (20.4-31.1) and 21.1% (16.3-26.3) at 24 months. Overall, 92% of pts were evaluable for HER2 status by IHC (HER2 IHC0, n=217; HER2-low, n=283). SG demonstrated improved OS versus TPC in the HER2 IHC0 (median, 13.6 vs 10.8 mo; HR, 0.86 [95% CI, 0.63-1.13]) and HER2-low (median, 15.4 vs 11.5 mo, HR, 0.74 [95% CI, 0.57-0.97) groups. Updated safety will be reported at the time of presentation. Conclusions: The final OS analysis of the TROPiCS-02 study confirms the clinically meaningful OS benefit of SG over single-agent CT in pts with pretreated, endocrine-resistant HR+/HER2–mBC. This improvement was independent of HER2-low status. This analysis reinforces SG as an effective and safe treatment for this pt population with limited treatment options. Clinical trial information: NCT03901339 .

185O Trastuzumab deruxtecan (T-DXd) vs treatment of physician’s choice (TPC) in patients (pts) with HER2-low unresectable and/or metastatic breast cancer (mBC): A detailed safety analysis of the randomized, phase III DESTINY-Breast04 trial

DESTINY-Breast04 (NCT03734029) demonstrated significantly improved overall and progression-free survival (PFS) with T-DXd vs TPC in pts with HER2-low (immunohistochemistry [IHC] 1+ or IHC 2+/in situ hybridization-negative) mBC, with manageable safety. Here, we report additional safety data. Pts with centrally confirmed HER2-low mBC, treated with 1-2 prior lines of chemotherapy, were randomly assigned 2:1 to receive T-DXd or TPC. An analysis of selected treatment-emergent adverse events (TEAEs) and age (<65 vs ≥65 years [y]) was done; endpoints included time to first onset (TTO), duration of first event (DUR), and resolution. At data cutoff (January 11, 2022), median (m) treatment duration was 8.2 months (mo; range [r], 0.2-33.3) for T-DXd vs 3.5 mo (r, 0.3-17.6) for TPC. Exposure-adjusted incidence rates (EAIRs; per pt-y) for any-grade TEAEs were lower for T-DXd vs TPC (1.30 vs 2.66). mTTO and mDUR of any-grade interstitial lung disease (ILD) in pts treated with T-DXd were 129 days (d; r, 26-710 d) and 47 d (r, 13-365 d). 13 pts had adjudicated drug-related grade 1 ILD; of those pts, 6 were rechallenged with T-DXd after resolution (details to be presented). Incidence of any-grade drug-related neutropenia (NP) and febrile NP was lower for T-DXd vs TPC; subsequent granulocyte colony-stimulating factor use was 6.7% vs 19.8%. Nausea/vomiting (N/V) events in T-DXd vs TPC were 79.5% vs 35.5%. T-DXd-treated pts received more antiemetic prophylaxis (AP; 50.9%) vs TPC-treated pts (37.2%); 92.3% of T-DXd and 68.8% of TPC N/V events in AP-treated pts resolved. Incidence of any-grade drug-related TEAE was consistent between pts aged <65 y and ≥65 y. For T-DXd, incidence of grade ≥3 TEAEs and TEAEs associated with drug discontinuations (DD) was higher in pts aged ≥65 y compared to those aged <65 y; the most common TEAE associated with DD was ILD/pneumonitis. However, mPFS favored T-DXd over TPC in all patients, regardless of age. EAIR, TTO, and DUR data for selected TEAEs will be presented. T-DXd demonstrated a manageable safety profile to support its use as the new standard of care in pts with HER2-low mBC.

190MO Association of 18-Gene expression profile (GEP) with clinical outcomes in patients with metastatic triple-negative breast cancer (mTNBC) treated with pembrolizumab (Pembro) or chemotherapy (Chemo) in KEYNOTE-119

In the phase III, randomized, open-label KEYNOTE-119 (NCT02555657) study, second- or third-line treatment with pembro monotherapy did not significantly improve OS vs single-agent chemo treatment of physician’s choice (TPC) in patients (pts) with mTNBC, although the pembro treatment effect increased with increasing PD-L1 enrichment. In this exploratory analysis, we evaluated the association of T-cell-inflamed gene expression profile (GEP) with clinical outcomes from KEYNOTE-119. Pts with centrally confirmed mTNBC, ECOG PS ≤1, and 1-2 prior systemic treatments for metastatic breast cancer were randomized 1:1 to pembro 200 mg Q3W for up to 35 cycles or TPC (capecitabine, eribulin, gemcitabine, or vinorelbine) per local guidelines. Tumor RNA profiling was conducted on the RNA-seq platform (Illumina, San Diego, CA). Association of GEP with clinical outcomes was evaluated by logistic regression (best objective response [BOR] per RECIST v1.1) and Cox proportional hazards models (PFS and OS) with baseline adjustment for ECOG PS; 95% CIs for BOR were estimated using the Clopper and Pearson method. As of April 11, 2019, GEP data for 333 pts (pembro, n=177; TPC, n=156) were available for analysis. GEP was significantly associated with improved BOR, PFS, and OS in pts treated with pembro but not TPC (Table). HR for OS was 0.77 (95% CI, 0.58–1.04) in pts with GEP non-low (≥1st tertile) and 1.72 (1.15–2.55) in pts with GEP low (<1st tertile). No association was seen between BRCA/HRD status and treatment response. These findings suggest a positive association between GEP and clinical outcomes in pts with mTNBC who are treated with pembro, with a more favorable treatment effect in the GEP-enriched population. Results may help inform future analyses of outcomes by biomarker status in this population.

186O Patient-reported outcomes (PROs) from DESTINY-Breast02, a randomized phase III study of trastuzumab deruxtecan (T-DXd) vs treatment of physician’s choice (TPC) in patients (pts) with HER2–positive (HER2+) metastatic breast cancer (mBC)

186O Patient-reported outcomes (PROs) from DESTINY-Breast02, a randomized phase III study of trastuzumab deruxtecan (T-DXd) vs treatment of physician’s choice (TPC) in patients (pts) with HER2–positive (HER2+) metastatic breast cancer (mBC)

192MO DESTINY-Breast04 subgroup analyses of trastuzumab deruxtecan (T-DXd) vs treatment of physician’s choice (TPC) in patients (pts) with human epidermal growth factor 2 (HER2)-low, estrogen-receptor (ER) expression immunohistochemistry (IHC) 0-10% metastatic breast cancer (mBC)

192MO DESTINY-Breast04 subgroup analyses of trastuzumab deruxtecan (T-DXd) vs treatment of physician’s choice (TPC) in patients (pts) with human epidermal growth factor 2 (HER2)-low, estrogen-receptor (ER) expression immunohistochemistry (IHC) 0-10% metastatic breast cancer (mBC)

Health-Related Quality of Life in Patients With Advanced Endometrial Cancer Treated With Lenvatinib Plus Pembrolizumab or Treatment of Physician’s Choice

PurposeLenvatinib and pembrolizumab (LEN+PEMBRO) demonstrated clinically meaningful and statistically significant improvements in efficacy versus treatment of physician’s choice (TPC) in patients with advanced endometrial cancer (aEC) in the phase 3 Study 309/KEYNOTE-775. Health-related quality-of-life (HRQoL) is reported. Patients and MethodsPatients were randomly assigned to receive LEN+PEMBRO (n = 411; LEN 20 mg/day; PEMBRO 200 mg Q3W) or TPC (n = 416; doxorubicin 60 mg/m2 Q3W or paclitaxel 80 mg/m2 [weekly, 3 weeks on/1 week off]). Impact of treatment on HRQoL assessed by the global health status/quality of life (GHS/QoL) score of the European Organisation for Research and Treatment of Cancer Quality-of-Life Questionnaire (EORTC QLQ-C30) was a secondary objective; other scales of the Quality-of-Life Questionnaire (QLQ-C30), EORTC QLQ-Endometrial, 24 questions (EORTC QLQ-EN24), and EuroQoL 5 dimensions, 5 levels (EQ-5D-5L) were exploratory objectives. HRQoL was assessed on day 1 of each cycle. Completion/compliance, change from baseline, time to first and definitive deterioration were assessed. No multiplicity adjustments were applied for HRQoL endpoints. ResultsThe latest timepoint at which the predefined rates of completion (≥60%) and compliance (≥80%) were met was week 12. HRQoL at week 12 between treatment groups was generally similar. Time to first deterioration symptom scales favoured LEN+PEMBRO for QLQ-C30 dyspnoea, and QLQ-EN24 for poor body image, tingling/numbness, and hair loss; and TPC was favoured for QLQ-C30 pain, appetite loss, and diarrhoea, and QLQ-EN24 muscular pain. While the QLQ-C30 physical functional scale favoured TPC, other functional scales were generally similar between arms. Time to definitive deterioration favoured LEN+PEMBRO on most scales. ConclusionHRQoL data from Study 309/KEYNOTE-775, with previously published efficacy and safety results, indicate that LEN+PEMBRO has an overall favourable benefit/risk profile versus TPC for the treatment of patients with aEC. ClinicalTrials.govNCT03517449.

Abstract P4-07-65: Effect of sacituzumab govitecan vs chemotherapy in HR+/HER2- metastatic breast cancer: patient-reported outcomes from the TROPiCS-02 trial

Abstract Background: For HR+/HER2- metastatic breast cancer (MBC) patients, after resistance to endocrine therapy (ET), treatment options are mostly limited to traditional chemotherapies (CT) that offer poor survival and quality of life (QoL), creating an area of unmet need. The antibody-drug conjugate sacituzumab govitecan (SG) comprises an anti-Trop-2 antibody coupled to SN-38 via a hydrolyzable linker. In the phase 3 TROPiCS-02 trial, heavily pretreated patients with relapsed/refractory HR+/HER2- MBC received SG vs single-agent chemotherapy treatment of physician’s choice (TPC). The study met its primary endpoint of improved progression-free survival with SG vs TPC. Here, we report the effect of SG vs TPC on patient-reported outcomes (PROs) from TROPiCS-02. Patients and Methods: Patients who had received ≥1 CDK 4/6 inhibitor, ≥1 ET, and 2-4 prior lines of CT were randomized to receive SG (10 mg/kg intravenous on days 1 and 8 of a 21-day treatment cycle) or TPC (capecitabine, eribulin, gemcitabine, or vinorelbine). In the PRO-evaluable population (all randomized patients with an evaluable assessment at baseline (BL) and ≥1 post-BL visit) SG and TPC were compared regarding time to first clinically meaningful worsening (TTD) or death from BL on the EORTC QLQ-C30 domains (≥10 points), EQ-5D-5L health utility index (≥0.08 points), and EQ-VAS (≥7 points). For the EORTC QLQ-C30 function and global health status/QoL domains, patients with a BL score ≥10 and for symptom scales, patients with a BL score ≤90 were included. In the safety population (all randomized patients who received ≥1 dose of study drug), SG and TPC were compared regarding worst level of toxicities during treatment for the PRO-CTCAE items. For TTD, a stratified Cox proportional hazards regression analysis was conducted and the PRO-CTCAE items were summarized descriptively (numbers and percentages). Results: Of 543 randomized patients, 446 (82%), 445 (82%), and 517 (95%) were included in the PRO-evaluable population (EORTC QLQ-C30: SG vs TPC n=236 vs 210 and EQ-5D-5L: n=238 vs 207) and in the safety population for PRO-CTCAE (SG vs TPC n=268 vs 249), respectively. TTD of EORTC QLQ-C30 global health status/QoL, physical functioning, emotional functioning, fatigue, dyspnea, insomnia, and financial difficulties and EQ-VAS were significantly longer in the SG vs the TPC arm (Table). TTD of EORTC QLQ-C30 diarrhea was significantly shorter for SG vs TPC. For PRO-CTCAE items, decreased appetite, nausea, vomiting, constipation, abdominal pain, shortness of breath, and fatigue were similar between SG and TPC arms, whereas frequency of diarrhea and amount of hair loss were higher in the SG vs TPC arm. Conclusions: In this trial, SG significantly delayed worsening of overall QoL, physical and emotional functioning, and symptoms like fatigue, dyspnea, and insomnia. Overall, our findings suggest that SG has more favorable effects on PROs compared with TPC in pts with HR+/HER2- MBC. Table: Time to First Clinically Meaningful Deterioration PRO Scores Citation Format: Frederik Marmé, Aditya Bardia, Hope Rugo, Peter Schmid, Sara M. Tolaney, Mafalda Oliveira, Andreas Schneeweiss, Ling Shi, Wendy Verret, Mahdi Gharaibeh, Anju Shah, Javier Cortés. Effect of sacituzumab govitecan vs chemotherapy in HR+/HER2- metastatic breast cancer: patient-reported outcomes from the TROPiCS-02 trial [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 P4-07-65.