Treatment Of Physician's Choice Research Articles

1471TiP MK-2870-015: A phase III study of trophoblast antigen 2 (TROP2)-directed antibody-drug conjugate (ADC) sacituzumab tirumotecan (sac-TMT) vs treatment of physician’s choice (TPC) for previously treated metastatic gastroesophageal adenocarcinoma (GEA)

1471TiP MK-2870-015: A phase III study of trophoblast antigen 2 (TROP2)-directed antibody-drug conjugate (ADC) sacituzumab tirumotecan (sac-TMT) vs treatment of physician’s choice (TPC) for previously treated metastatic gastroesophageal adenocarcinoma (GEA)

Trastuzumab deruxtecan versus treatment of physician’s choice in previously treated Asian patients with HER2-low unresectable/metastatic breast cancer: subgroup analysis of the DESTINY-Breast04 study

BackgroundIn the global phase 3 DESTINY-Breast04 study (NCT03734029), the anti-human epidermal growth factor 2 (HER2) antibody–drug conjugate trastuzumab deruxtecan (T-DXd) demonstrated a statistically significant improvement in progression-free survival (PFS) and overall survival (OS), with manageable safety compared with treatment of physician’s choice (TPC) in patients with HER2-low metastatic breast cancer (mBC) who had received 1–2 prior lines of chemotherapy.MethodsThis subgroup analysis examined the efficacy and safety of T-DXd versus TPC in 213 patients from Asian countries and regions who were enrolled in the DESTINY-Breast04 trial and randomized to T-DXd (n = 147) or TPC (n = 66).ResultsMedian PFS with T-DXd and TPC was 10.9 and 5.3 months, respectively, in Asian patients with hormone receptor-positive mBC, and 10.9 and 4.6 months, respectively, in the overall Asian population. In both populations, median OS was not reached with T-DXd and was 19.9 months with TPC. The objective response rate was higher with T-DXd versus TPC in all Asian patients. Median treatment duration was 8.4 months with T-DXd and 3.5 months with TPC. The most common grade ≥ 3 drug-related treatment-emergent adverse events in Asian patients treated with T-DXd were neutropenia (16.3%), anemia (12.9%), and leukopenia (11.6%); the incidences of neutropenia and leukopenia were higher with TPC versus T-DXd. Adjudicated drug-related interstitial lung disease or pneumonitis with T-DXd was 14.3%; the majority of events were grade 1–2.ConclusionsT-DXd demonstrated clinically meaningful survival benefits versus TPC in Asian HER2-low mBC patients, regardless of hormone receptor status, with no new safety signals.Clinical trial registration numberClinicalTrials.gov, NCT03734029.

Antibody-drug conjugates (ADC) in patients with advanced/metastatic HER2-low expressing breast cancer: A systematic review and meta-analysis.

e13174 Background: Historically, HER2-targeted therapies failed to improve survival of patients with HER2-low-expressing tumors. Recently, trastuzumab deruxtecan (T-DXd), an antibody-drug conjugate (ADC), demonstrated superior outcomes compared with treatment of physician´s choice (TPC) in this population. Other ADCs have also shown encouraging results, including sacituzumab govitecan (SG), MRG002, and RC48-ADC. Hence, we performed a systematic review and meta-analysis to assess the effectiveness of ADCs in patients with HER2-low advanced/metastatic (a/m) breast cancer (BC). Methods: We searched PubMed, Embase, and Cochrane databases and ASCO, ESMO, and SABCS websites for studies evaluating ADCs on patients with HER2-low a/mBC. Outcomes of interest were objective response rate (ORR); disease control rate (DCR); clinical benefit rate (CBR); progression-free survival (PFS); and overall survival (OS). We used R software (v.4.2.2) and random effects models for all analyses. Heterogeneity was assessed using I2 test. Results: Overall, 12 studies were included (3 real-world studies and 9 clinical trials), with 1,292 HER2-low a/mBC patients, 378 received TPC, and 914 received ADCs. Most were treated with T-DXd (63%, n=572), SG (29%, n=268), MRG002 (6%, n=56), and RC48-ADC (2%, n=18). Median age ranged from 48.1 to 58 years, and follow-up from 9.5 to 18.4 months. Patients treated with T-DXd achieved a significantly higher ORR and DCR compared to those who received SG, RC48-ADC, and MRG002 (Table). CBR was numerically higher in patients on T-DXd than those on SG but did not reach a significant difference. Patients with HR-positive tumors treated with SG had an ORR of 45% (95% CI 23 – 67%), and patients with pure HER2-low treated with any ADC, had an ORR of 38% (95% CI 30 – 45%). In the pooled analysis of 3 RCTs, ADCs significantly prolonged PFS compared with TPC (n=963, HR: 0.44, 95% CI 0.32 – 0.61, I2 = 66%, p<0.001), and OS (n= 680, HR: 0.56, 95% CI 0.36 – 0.89, I2 = 73%, p=0.015). Patients on ADCs also achieved a greater anti-tumor response than TPC, including better ORR (OR: 4.18, 95% CI 2.40 - 7.28, I2 = 52%, p<0.001), DCR (OR: 2.82, 95% CI 2.06 - 3.85, I2 = 7%, p<0.001), and CBR (OR: 3.41, 95% CI 2.36 - 4.93, I2 = 25%, p<0.001). Conclusions: Our systematic review and meta-analysis supports the efficacy of ADCs in HER2-low a/mBC patients over TPC. Future studies should focus on bringing ADCs into earlier lines of therapy in this population.Anti-tumor activity of ADCs presented as overall % (95% CI). [Table: see text]

IDeate-Lung02: A phase 3, randomized, open-label study of ifinatamab deruxtecan (I-DXd) vs treatment of physician’s choice (TPC) in relapsed small cell lung cancer (SCLC).

TPS8126 Background: SCLC is an aggressive malignancy, and patients (pts) with extensive stage (ES)-SCLC have a relatively short median overall survival (OS), with limited treatment options beyond first-line (1L) therapy. B7 homolog 3 (B7-H3 [CD276]) is a transmembrane protein expressed in many solid tumors but with low/no expression in normal tissue. In SCLC, B7-H3 is highly expressed and associated with poor prognosis and lack of response to standard therapy. I-DXd is a B7-H3-directed antibody–drug conjugate comprising an anti-B7-H3 mAb linked to a topoisomerase I inhibitor payload (DXd) via a stable cleavable linker, designed to enhance selective tumor cell death and reduce systemic exposure. I-DXd demonstrated durable efficacy (objective response rate [ORR] 52.4%; median duration of response [DoR] 5.9 mo; median OS 12.2 mo) irrespective of B7-H3 status, with a manageable safety profile in 21 ES-SCLC pts with a median of 2 prior lines of therapy in a Phase 1/2 trial (NCT04145622). I-DXd is being investigated in an ongoing Phase 2 trial in pretreated ES-SCLC, IDeate-Lung01 (NCT05280470). We describe a Phase 3 trial comparing the efficacy and safety of I-DXd vs TPC in relapsed SCLC. Methods: IDeate-Lung02 (NCT06203210) is a global, multicenter, randomized, open-label, Phase 3 trial in adult pts with relapsed SCLC who have received 1 prior line of platinum-based therapy and have an ECOG PS of ≤1; pts with asymptomatic brain metastases are eligible. Pts are randomized 1:1 to receive I-DXd 12 mg/kg iv every 3 wks (n = 234) or TPC (n = 234; topotecan, amrubicin, or lurbinectedin). Randomization is stratified by chemotherapy-free interval after 1L therapy (< 90 vs ≥90 days); TPC (topotecan vs amrubicin vs lurbinectedin); prior treatment with PD-(L)1 (yes vs no); and presence/history of asymptomatic brain metastases (yes vs no). Study treatment continues until disease progression, unacceptable toxicity, withdrawal of consent, death, loss to follow-up, or other reasons per protocol. Radiographic tumor assessments occur every 6 wks for 48 wks, then every 12 wks. Dual primary efficacy endpoints are ORR per RECIST v1.1 by blinded independent central review (BICR) and OS. Secondary efficacy endpoints are ORR per investigator; progression-free survival, DoR, disease control rate and time to response by BICR and investigator; and patient-reported outcomes. Safety endpoints include incidence of treatment-emergent adverse events (TEAEs), deaths, serious TEAEs, and TEAEs leading to dose modification or discontinuation. Immunogenicity of I-DXd and relationship between B7-H3 expression and clinical outcome are also secondary objectives. ORR will be analyzed using a Cochran-Mantel-Haenszel test at a 2-sided 1% alpha level, and OS will be analyzed using a log-rank test at a 2-sided 4% significance level, under a 2-look group sequential design. Clinical trial information: NCT06203210 .

Genomic alterations in DNA damage response (DDR) genes in HR+/HER2- metastatic breast cancer (mBC) and impact on clinical efficacy with sacituzumab govitecan (SG): Biomarker results from TROPICS-02 study.

1075 Background: In the phase 3 TROPiCS-02 study, SG, a Trop-2–directed antibody-drug conjugate coupled to SN-38 as the payload, demonstrated clinically meaningful improvement in survival outcomes over chemotherapy in patients (pts) with pretreated HR+/HER2- mBC. SN-38 leads to double-stranded DNA damage, therefore we hypothesized that in tumors with defective DDR machinery, SG may provoke synthetic lethality. We report on comprehensive genomic analysis of DDR gene variants and the impact on SG clinical efficacy in this patient population. Methods: Pts with HR+/HER2– mBC who received prior taxane, endocrine therapy (ET), CDK4/6 inhibitor, and 2-4 prior lines of chemotherapy were randomized to receive SG (10 mg/kg IV days 1 and 8, every 21 days) or treatment of physician’s choice (TPC) until disease progression or unacceptable toxicity. DDR gene deleterious variants were identified using whole exome sequencing (WES) on archival or screening tumor tissues based on 142 DDR pathway genes annotated in the Kyoto Encyclopedia Genes and Genomes (KEGG) database and Human DNA Repair Gene database; association between these variants and clinical outcomes was evaluated using Cox regression model as Hazard Ratio (HR) with 95% Confidence Intervals (CI). Results: Of 543 patients included in the intent-to-treat (ITT) population, WES data was available for 195 (36%) – clinicopathological features were similar between ITT and WES dataset (median age = 57 vs 58 for SG and 55 vs 55 for TPC; prior lines of chemotherapy >2 lines = 59% vs 57% for SG and 58% vs 55% for TPC). Estrogen Receptor (ER)>10% and prior lines of chemotherapy were comparable between WT and MUT in SG arm and in TPC arm. Overall, 114 (58%) of tumor samples had ≥1 deleterious alteration with BRCA2, PRKDC, ATM being the most common alterations. The primary results are included (Table). Although all patients demonstrated improved efficacy with SG vs TPC, patients with DDR mutant MBC had numerically greater benefit in PFS vs WT (MUT HR= 0.61; WT HR= 0.76) and OS (MUT HR = 0.68; WT HR= 0.82). Conclusions: While SG benefit over TPC was observed in both DDR WT and DDR MUT HR+/HER2– mBC, numerically greater benefit was observed for patients with DDR deficient tumors, suggesting possible synergy between the DDR pathway and SG’s anti-tumor effect. Further study of the synergistic effects of SG in combination with agents targeting DDR pathway are warranted. Clinical trial information: NCT03901339 . [Table: see text]

Primary results from PATRICIA cohort C (SOLTI-1303), a randomized phase II study evaluating palbociclib with trastuzumab and endocrine therapy in pretreated HER2-positive and PAM50 luminal advanced breast cancer.

1008 Background: The PATRICIA trial (cohorts A-B) demonstrated that palbociclib plus trastuzumab (T) is safe and active in patients (pts) with T-pretreated HER2-positive Hormone Receptor-positive (HR+/HER2+) PAM50 Luminal advanced breast cancer (ABC). Here, we present the primary efficacy analysis of the randomized cohort C from the PATRICIA trial that compares the efficacy of palbociclib + T + endocrine therapy (ET) with treatment of physicians’ choice (TPC). Methods: PATRICIA (cohort C) is a randomized, open-label, phase II study conducted at 34 sites in Spain recruiting from August 2019 to August 2023. Pts with HER2+/HR+ and centrally tested PAM50 Luminal A or B intrinsic subtype ABC who had received at least one prior line of anti-HER2 based regimens were eligible. Pts were randomized 1:1 to Cohort C1 (Palbociclib 125 mg/day orally 3 weeks/1 week off + T + ET) or Cohort C2 (TPC, including T + any ET or chemotherapy (CT) + T, or T-DM1). The stratification factors were number of previous regimens for ABC and presence of visceral disease. The primary endpoint was progression-free survival (PFS). The trial was designed to recruit a total of 102 pts, having an 80% power with one-sided alpha=0.1 to detect a HR of 0.62 in favor of the palbociclib cohort. The study was closed after 73 pts were randomized due to slow recruitment. Results: At data cut-off, 264 pts were pre-screened, and 73 pts were randomized. Baseline pts characteristics are summarized in Table 1. In cohort C1, 50% of the pts received fulvestrant and 50% aromatase inhibitor as ET. In cohort C2, 37.1% of pts were treated with TDM-1, 45.7% with CT+ T, 11.4 % with ET + T and two pts withdrew their consent before starting the treatment. Palbociclib + T + ET was associated with longer PFS compared to TPC (median 9.1 vs 7.5 months, stratified HR=0.52 [95%CI 0.29-0.94]; two-sided p=0.031); 12-months PFS rates were 43.7% and 21.4%, respectively. The overall response rate was 18.9% (95% CI 8.6-35.7) in cohort C1 and 8.3% (95% CI 1.4-28.5) in cohort C2. Grade ≥3 adverse events occurred in 63.2% of pts in C1 and 45.5% in C2 cohort. The most frequent grade ≥3 adverse event in the experimental arm was neutropenia (55.3%). Conclusions: The combination of palbociclib, T and ET showed a statistically significant improvement in PFS in patients with previously treated PAM50 luminal A or B HER2+ advanced breast cancer, as compared to TPC. Clinical trial information: NCT02448420 . [Table: see text]

Study of the Bria-IMT regimen and CPI vs physicians' choice in advanced metastatic breast cancer (BRIA-ABC).

TPS1137 Background: BriaCell (BC) human immortalized cell lines have been engineered to trigger robust immune responses and deliver efficacy through diverse mechanisms, including adaptive (involving T-cells) and innate responses (dendritic and NK cells). BC can match patients’ HLA antigens for optimal effectiveness. BC works by several mechanisms, including direct antigen presentation and activation of CD4+ T-cells. When combined with an immune checkpoint inhibitor, the BC regimen has demonstrated clinical benefit in 54 heavily treated MBCs. Most pts whose disease has progressed after checkpoint inhibitor (CPI) therapy showed similar or improved PFS compared to the patient's last treatment regimen. Disease control after prior antibody-drug conjugates (ADCs) has been observed in 40% of patients, and clinical benefit has been seen in 5/7 patients with untreated intracranial metastases. CD8+ Immuno PET shows an increase in CD8+ tumor infiltrating lymphocytes suggesting systemic activation and infiltration into lymphoid organs and metastatic sites. Sequencing of CPI with BC and the latest phase 3 formulation are associated with improved clinical outcomes, including OS (median 13.4 months), PFS, and CBR, which are reflected in the design of this ongoing pivotal registration enabling Phase 3 study [doi:10.1158/1538-7445.sabcs22-p3-07-12]. Methods: Multicenter randomized, open label Bria-IMT regimen (with SV-BR-1-GM cells) plus CPI vs Treatment of Physicians' Choice (TPC) in MBCs with no approved curative therapies available. ECOG <2 allowed with no limit on prior therapies. Eligibility encompasses all MBC subtypes including pts with CNS metastases. Prior immune therapy is allowed if administered more than 21 days before the first cycle of Bria-IMT; treatments within 21 days preclude participation. Initial randomization will be 1:1:1 to the Bria-IMT regimen + CPI (combination), TPC, and the Bria-IMT regimen alone (monotherapy). There will be 100 sites across the US, Canada, and ex-NA for 404 total evaluable pts. The Bria-IMT regimen includes: Day -2 Cyclophosphamide 300mg/m2, Day 0 20 million irradiated SV-BR-1-GM cells intradermally, and 0.1mcg peg α interferon intra-dermally (Day 2 or 3) into each Bria-IMT inoculation site. After the first 150 pts have enrolled, the monotherapy arm will be discontinued. Bria regimen + CPI arms treatment cycles occur q3w. CPI infusion is given every cycle between Day –3 to Day 3 TPC cycle details will be according to the site's SOC. Imaging assessment will be q6w x2 then q8w. The primary endpoint is overall survival with an interim analysis at 144 events targeting a hazard ratio of 0.6. Key secondary endpoints will include PFS, ORR, CBR, CNS event free survival, and TWiST (time without symptoms or toxicities). Safety analysis will be ongoing. Patient-reported outcomes will be incorporated to assess subjective treatment effects. Clinical trial information: NCT06072612 .

Safety profile of sacituzumab govitecan in patients with breast cancer: A systematic review and meta-analysis.

e13106 Background: Sacituzumab govitecan (SG), a first-in-class TROP-2-directed antibody conjugated to a topoisomerase inhibitor, has shown antitumor activity across various breast cancer (BC) subtypes. Following SG approval for metastatic triple negative breast cancer (TNBC) and its broad use, understanding SG’ safety profile is crucial. Hence, we conducted a systematic review and meta-analysis to evaluate the safety and tolerability of SG in patients with BC. Methods: We comprehensively searched PubMed, Embase, and Cochrane databases, and ASCO and ESMO websites for clinical trials assessing the safety of SG in BC patients. Outcomes of interest included treatment-related adverse events (TRAEs) of any grade, grade 3/4, adverse events (AEs) leading to death, and AEs leading to SG dose reduction or discontinuation. All analyses were performed in R software (v.4.2.2) using random effects models. Heterogeneity was assessed using I2 test. Results: A total of 1,325 patients from six studies – three randomized clinical trials (RCTs) and three non-RCTs – were included. Median age of population ranged from 47 to 56 years. Most had metastatic disease (86%, n=1187), and triple-negative BC (48.6%, n=670). Regarding therapies, 798 patients received SG and 527 had treatment of physician's choice (TPC). In the pooled analysis of 748 patients on SG, the overall risk of AEs was 100% (95% CI 99-100%). The estimated risk of the most common all grade AEs were neutropenia (66%), anemia (44%), nausea (56%), vomiting (30%), fatigue (46%), constipation (17%), diarrhea (45%), and alopecia (46%), as described (Table). The risk of grade 3/4 AEs among 748 patients on SG was 55% (95% CI 36-74%). Neutropenia was the most important grade ≥3 AE, with a estimated frequency of 47%; followed by anemia and diarrhea, with an incidence of at 9% and 7%, respectively. The incidence of all other grade 3/4 AEs (e.g. anemia, vomiting, leukopenia, fatigue, constipation, and diarrhea) was below 10%. Dose reduction and discontinuation were observed in 14.4% and 2.9% of patients, respectively. Toxicity-related deaths occurred in six patients (0.4%). In a comparative sensitivity analysis of RCTs only, SG had significantly higher toxicity than TCPs, all grade AEs (OR 12.30 95%CI 1.68-89.87, p=0.01), and grade >3 AEs (OR 1.69 95%CI 1.25-2.28, p=0.0006). Conclusions: In this systematic review and meta-analysis, SG was associated with a high incidence of AEs. Neutropenia is a notable and potentially serious adverse event. Toxicity associated with SG may be addressed through close monitoring and early management. [Table: see text]

Health-related quality of life with sacituzumab govitecan in HR+/HER2- metastatic breast cancer in the phase III TROPiCS-02 trial.

The TROPiCS-02 study (NCT03901339) demonstrated that sacituzumab govitecan (SG) has superior clinical outcomes over treatment of physician's choice (TPC) chemotherapy in patients with hormone receptor-positive, human epidermal growth factor 2 receptor-negative (HR+/HER2-) metastatic breast cancer (mBC). Here, we present health-related quality of life (HRQoL) patient-reported outcome (PRO) findings from this study. Eligible adults with HR+/HER2- mBC who previously received a taxane, endocrine-based therapy, a CDK4/6 inhibitor, and 2-4 lines of chemotherapy were randomized 1:1 to receive SG or TPC until progression or unacceptable toxicity. PROs were assessed at baseline and on day 1 of each cycle, using the European Organization for Research and Treatment of Cancer Quality-of-Life Core 30 (EORTC QLQ-C30), EQ-5D-5L, and PRO Common Terminology Criteria for Adverse Events (PRO-CTCAE). Compared to TPC, overall least square mean change from baseline was significantly better for SG for physical functioning and dyspnea, but worse for diarrhea. Time to first clinically meaningful worsening or death was significantly longer for SG in global health status/quality of life, physical functioning, fatigue, emotional functioning, dyspnea, insomnia, and financial difficulties of the EORTC QLQ-C30 and the EQ-VAS, but longer for TPC in diarrhea. Few patients in both arms reported experiencing any worsening to level 3 or 4 treatment-related symptomatic events during treatment, as assessed by 16 PRO-CTCAE items, except for diarrhea frequency and amount of hair loss, which favored TPC. SG was associated with an HRQoL benefit in most symptoms and functioning, compared with TPC. This supports the favorable profile of SG as a treatment option for patients with pretreated HR+/HER2- mBC.

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)