Junction Adenocarcinoma Research Articles

467P Novel staging schemes for Siewert type II esophagogastric junction adenocarcinoma: A real-world data cohort study from SEER database

467P Novel staging schemes for Siewert type II esophagogastric junction adenocarcinoma: A real-world data cohort study from SEER database

A phase 1b, multicenter, open-label study of valemetostat in combination with DXd antibody drug conjugates (ADCs), trastuzumab deruxtecan (T-DXd) or datopotamab deruxtecan (Dato-DXd), in patients with solid tumors.

TPS4180 Background: Valemetostat tosylate (valemetostat) is a novel, potent, and selective dual inhibitor of enhancer of zeste homolog (EZH) 2 and EZH1. Valemetostat 200 mg PO QD has demonstrated clinical efficacy and favorable tolerability in multiple hematologic malignancies. EZH2 controls gene expression, including the expression of genes involved in DNA damage response, like DNA/RNA helicase Schlafen 11 ( SLFN11). In response to DNA damage, SLFN11 binds to chromatin, causing a replication block and inducing apoptosis. Expression levels of SLFN11 indicate sensitivity to DNA-damaging agents (DDAs) in various solid tumors and are downregulated in chemotherapy-resistant tumor cells due to trimethylation of H3K27 at the SLFN11 gene locus. EZH2 inhibition by valemetostat is expected to upregulate SLFN11 and sensitize tumor cells to DDAs. Topoisomerase inhibition causes DNA strand breaks, which may synergize with valemetostat. This study will combine valemetostat with topoisomerase-I inhibitor ADCs, T-DXd or Dato-DXd, for the first time in patients (pts) with HER2-positive (HER2+) gastric cancer (GC) and non-squamous non-small-cell lung cancer (NSCLC), respectively. T-DXd is globally approved for the treatment of pts with locally advanced or metastatic HER2+ GC and other cancers, having received prior anti-HER2–based treatment. In the phase 3 TROPION-Lung01 trial, Dato-DXd significantly improved progression-free survival (PFS) vs standard chemotherapy in previously treated, locally advanced or metastatic NSCLC. Methods: This global, phase 1b, multicenter, two-part, open-label study is structured as a Master Protocol with independent sub-protocols defined by disease and treatment combination, including valemetostat + T-DXd in pts with 2L+ advanced or metastatic HER2+ GC or gastro-esophageal junction adenocarcinoma, and valemetostat + Dato-DXd in pts with 2L+ locally advanced, unresectable, or metastatic non-squamous NSCLC. Target enrollment is 70 pts per sub-protocol across 35 sites in US and Japan. Part 1 will determine the valemetostat recommended dose for expansion (RDE), combining escalating doses of valemetostat 50–200 mg PO QD with T-DXd at 5.4 mg/kg or 6.4 mg/kg (dose after first escalation) IV Q3W (GC protocol), or with fixed dose Dato-DXd 6.0 mg/kg IV Q3W (NSCLC protocol). Part 2 will evaluate the efficacy of valemetostat QD + Dato-DXd or T-DXd at the RDE. The main eligibility criteria for both protocols include at least 1 measurable lesion (per RECIST v1.1), an ECOG PS score of 0–1, and adequate organ function. Primary endpoints of this study are safety and tolerability of valemetostat in Part 1 and objective response rate in Part 2. Secondary endpoints include duration of response, PFS, overall survival and pharmacokinetics. Clinical trial information: NCT06244485 .

FS-1502 in patients with HER2 high expression, locally advanced or metastatic gastric or gastroesophageal junction adenocarcinoma: An open-label, multicenter, phase II study.

e15000 Background: FS-1502 is an antibody-drug conjugate composed of an anti-HER2 antibody, linker, and Monomethylauristatin F. In this study, we conducted an open-label, multicenter, two-cohort phase II trial to evaluate the efficacy and safety of FS-1502 in HER2- positive locally advanced or metastatic gastric or gastroesophageal junction cancer. Methods: Pts with HER2-positive (IHC 3+ or 2+/FISH+) who had received ≥1 prior treatment regimens were eligible and received FS-1502 2.3 mg/kg alone every 3 weeks. The study consists of Cohort 1 for pts received ≥2 lines of previous therapy and Cohort 2 for pts only received first-line of previous therapy, respectively. The primary endpoint was the objective response rate (ORR). Secondary endpoints included progression free survival (PFS), overall survival (OS), duration of response, disease control rate, and safety. Results: At data cutoff (Dec 24,2023), 46 pts were enrolled (intent-to-treat [ITT]), 35 pts were confirmed HER2-positive (IHC 3+ or IHC 2+/ISH+, Efficacy Evaluable Set [ES]) by central laboratory. In the ES, the median age was 58.3 years, 48.6% were IHC3+ and primary tumor location in 77.1% of pts was GC. 45.7% (16/35) pts had assigned to cohort 1 and 54.3% (19/35) pts had assigned to cohort 2. In cohort 1, median study follow-up time was 10.1 months, the investigator-assessed ORR was 37.5% (95% CI, 15.2-64.6), median PFS and OS were 4.3 months (95% CI, 1.5-5.8 months) and 10.0 months (95% CI,5.1-NA months), respectively. In cohort 2, median study follow-up time was 12.5 months, the investigator-assessed ORR was 52.6% (95% CI, 28.9-75.6). PFS and OS were 4.4 months (95% CI, 3.0-7.3 months) and 14.6 months (95% CI, 8.7-NA months), respectively. Grade≥3 treatment-related TEAEs were reported in 12 (26.1%) pts, ≥5% were hypokalemia (6.5%) and fatigue(6.5%). No adverse events leading to drug discontinuation or death. Efficacy and safety data are shown in table. Conclusions: FS-1502 showed promising activity with tolerable and manageable safety profile, which warrants further development in HER2-postive, advanced gastric or gastroesophageal junction adenocarcinoma who had received ≥1 prior treatment regimens. [Table: see text]

Triple combination treatment of trastuzumab, chemotherapy and immune checkpoint inhibitor in HER2 positive unresectable, locally advanced, metastatic gastric and esophageal adenocarcinoma: A systematic review and meta-analysis.

e16071 Background: The current standard of care for unresectable, locally advanced or metastatic HER2 positive gastric, esophageal and gastroesophageal junction adenocarcinomas is the combination of the anti HER 2 antibody trastuzumab and cytotoxic chemotherapy. In recent years, the addition of immune checkpoint inhibitors to this combination has been studied to determine if it can improve clinical outcomes for this disease. This systematic review and meta-analysis evaluated high-quality data from clinical trials to determine the role and efficacy of this triple combination treatment. Methods: A systematic search of English-language articles on PubMed, Cochrane and Google scholar was done to identify randomized trials (RCTs) investigating the use of triple combination treatment of anti-Her 2 antibody, chemotherapy and immune checkpoint inhibitor in the treatment of unresectable, locally advanced, or metastatic HER2 overexpression positive gastric, esophageal and gastroesophageal junction adenocarcinoma. Quality of the studies was assessed using the Revised Cochrane risk-of-bias tool for randomized trials (RoB 2). Inverse variance was the statistical method used with random effects as the analysis model in the production of the Forest plot and calculation of risk ratio (RR) at 95% confidence intervals (CI). Results: Four (4) RCTs (N = 866) were included for quality assessment and data extraction. Two (2) of these RCTs (N = 80) were single arm studies which both showed favorable outcomes in terms of objective response rate and progression free survival. The two (2) other RCTS (N = 786), each had two arms (triple regimen versus comparator) and were used in the meta-analysis. Risk of bias was low and heterogeneity was low (I2 below 50%). Pooled results showed that in patients given triple combination regimen, there is statistically significant improvement in progression free survival (RR 1.55 95% CI 1.20-2.00, p 0.0007). There is also an increase in overall response rate in favor of the triple combination regimen, albeit not statistically significant (RR 1.31 95% CI 0.99-1.74, p = 0.06). Conclusions: The addition of an immune checkpoint inhibitor to the current standard of care of anti Her 2 antibody and chemotherapy provides meaningful results in terms of tumor response and progression free survival in Her 2 positive locally advanced or metastatic gastric and esophageal adenocarcinomas. More robust trials, and data on overall survival supporting the use of this triple regimen may help re-shape the current standard of care for this disease.

Efficacy and safety of SOX regimen combined with inetetamab as first-line treatment for HER2-positive advanced gastric cancer.

e16028 Background: Patients with HER2-positive advanced gastric cancer have a poor prognosis. Trastuzumab combined with chemotherapy is the first-line standard treatment. Inetetamab is a novel anti-HER2 drug, and its efficacy and safety in gastric cancer have not been reported yet. Methods: Thirty-eight patients with HER2-positive advanced gastric cancer or gastroesophageal junction adenocarcinoma were randomly divided into two groups: one group received inetetamab combined with the SOX regimen, and the other group received trastuzumab combined with the SOX regimen. After 4-6 cycles, patients with stable disease received maintenance therapy. The primary endpoints were progression-free survival (PFS) and overall survival (OS), and the secondary endpoints were the objective response rate (ORR), disease control rate (DCR), and adverse events (AEs). Results: Thirty-seven patients completed the trial, with 18 patients in the inetetamab group and 19 patients in the trastuzumab group. In the inetetamab group, the median PFS was 8.5 months, compared to 7.3 months in the trastuzumab group (P = 0.046), indicating a significant difference. The median OS was 15.3 months vs. 14.3 months (P = 0.46), and the ORR was 50% vs. 42% (P = 0.63), with no significant differences between groups. Common AEs included leukopenia, thrombocytopenia, nausea, and vomiting. The incidence rates of grade ≥ 3 AEs were 56% in the inetetamab group and 47% in the trastuzumab group (P = 0.63), with no significant difference. Conclusions: In the first-line treatment of HER2-positive advanced gastric cancer, the efficacy of inetetamab and trastuzumab was comparable. The inetetamab group had superior PFS benefits, and both groups had good safety.

397MO Tislelizumab (TIS) plus chemotherapy (CT) vs placebo (PBO) plus CT in HER2-negative advanced or metastatic gastric or gastro-esophageal junction adenocarcinoma (GC/GEJC): PD-L1 biomarker analysis from RATIONALE-305

397MO Tislelizumab (TIS) plus chemotherapy (CT) vs placebo (PBO) plus CT in HER2-negative advanced or metastatic gastric or gastro-esophageal junction adenocarcinoma (GC/GEJC): PD-L1 biomarker analysis from RATIONALE-305

Safety and efficacy of intensified preoperative management of locally advanced gastrorsophageal junction cancer (INPROVE).

e16110 Background: The optimal management of locally advanced gastroesophageal junction adenocarcinoma (LAGEJad) is not fully established yet. Both neoadjuvant chemoradiotherapy (CRT) and perioperative taxane-based triplet chemotherapy (CT) are acknowledged treatment options for Siewert I and II cancers. In this retrospective study, we aimed to assess the safety and outcomes of an intensified preoperative regimen combining taxane-based triplet CT and CRT. Methods: We conducted a retrospective analysis of a cohort comprising 16 consecutive HER2 negative patients (pts) with LAGEJad treated at the Centro di Riferimento Oncologico of Aviano between 2019 and 2022. All pts received induction CT (iCT) consisting of fluoropyrimidine, oxaliplatin and docetaxel, followed by CRT (45Gy/25Fr) with simultaneous boost and concomitant CT. Surgery (Ivor-Lewis or McKeown) was performed 8 weeks post-CRT. Clinico-pathological (CP) and treatment features were analyzed using logistic regression to assess their association with response to iCT-CRT. The association of iCT-CRT with survival outcomes was investigated using the Kaplan-Meier method. Results: Key CP data are summarized in Table 1. Median age was 59 years, all pts were male. At diagnosis, 81.2% of pts exhibited cT3+ and cN+ disease. All pts received iCT and CRT. The rate of partial responses was 50% after iCT and 68.8% after CRT. Overall, 12 pts underwent surgery, all achieving R0 resections within a median timeframe of 9 [8.5;11] weeks post-CRT. Among them, 25% had a pathologic complete response, while 62.5% attained a Mandard tumor regression grade (TRG) of 1-2. No new safety signals emerged from iCT (only 2 pts had ≥G3 diarrhea) or CRT (≥G3 mucositis occurred in 6.2% and anemia in 6.2% of pts). No significant surgical delays were observed, although 5 pts experienced post-operative complications (4 grade I, 1 grade IIa). There were no statistically significant associations between CP variables and response to the iCT-CRT. Relapses were seen in 8 pts (2 locoregionally); 3-year survival was 46%. Median event-free survival was 5 [5;11] months, while median overall survival 34 [14;NR] months. Conclusions: The intensification of preoperative treatment in pts with LAGEJad is active and safe: the surgical schedule was not significantly delayed, and the safety profile remained comparable to standard regimens, with no major complications reported. Randomized clinical trials are ongoing to assess the clinical benefits of this approach. [Table: see text]

Efficacy of disitamab vedotin (RC48) plus tislelizumab and S-1 as first-line therapy for HER2-overexpressing advanced stomach or gastroesophageal junction adenocarcinoma: A multicenter, single-arm, phase II trial (RCTS).

4009 Background: Integrating immunotherapy with trastuzumab and chemotherapy has shown a significant improvement in overall response rate (ORR) and progression-free survival (PFS) in HER2-overexpression gastric or gastroesophageal junction cancer (GC/GEJC). However, the overall survival (OS) did not achievestatistical significance, and there was no benefit in patients with a PD-L1 combined positive score (CPS) <1. RC48, an antibody-drug conjugate drug, has proven its effect in advanced HER2-positive (HER2 3+ or 2+ by IHC, regardless of FISH positivity) GC/GEJC in later-line treatment setting. This trial was to assess the efficacy and safety of combining RC48, immunotherapy (Tislelizumab), and S-1 as a first-line treatment for HER2-overexpressing GC/GEJC. Methods: This was a single-arm, multi-center, phase II trial conducted in patients with HER2-overexpressing metastatic or unresectable GC/GEJC for first-line treatments. Participants received RC48 (2.5 mg/kg), Tislelizumab (200 mg), and S-1 (40-60 mg BID for 14 days) every 3 weeks until disease progression or intolerable toxicities. The primary endpoint was ORR, while the secondary endpoints included disease control rate (DCR), PFS, OS, and safety. Results: A total of 47 patients were enrolled from 8 centers, median 65 (39 ~ 81) years old, 37 male, 37 GC and 8 GEJC, and all adenocarcinoma. Of them, 30 (63.8%) were HER2 IHC 3+, 11 (23.4%) HER2 IHC 2+/FISH+, and 6 (12.8%) IHC 2+/FISH-. Patients with PD-L1 CPS≥5, ≥1 accounted for 14.9%, 36.2% respectively. With a median follow-up duration of 116.5 days, patients received a median of 5.0 treatment cycles. As of January 20, 2024, 40 patients were included for efficacy analysis, and 44 patients for safety. The ORR reached 95.0% (38/40, 95% CI: 83.1-99.4%), clinical Complete Response rate was 20.0% (5/40, 95% CI: 4.2-26.8%), and the DCR was 100.0% (95% CI: 91.2-100.0%). The median PFS and OS were not reached, while the 6-month and 9-month PFS rates were 100.0% and 80.8%, the 6-month and 9-month OS rates were 100.0% and 83.8%. ORR among the HER2 IHC 3+, IHC 2+/FISH+, and IHC 2+/FISH- groups showed no significant difference (93.3%, 100.0%, 100.0%). ORR for patients with CPS≥1 or < 1 were 100.0%, 92.9%, respectively. One stage IVA GC patient (cT4bN3M0, HER2 3+, CPS 0) and another stage IVB GEJC one (cT3N2M1, HER2 2+/FISH+, CPS≥5) received radical surgery and both achieved pathological complete response. Grade 3/4 treatment-related adverse events occurred in 40.9% of patients, notably neutropenia, fatigue, and diarrhea. Conclusions: The combination of RC48, Tislelizumab, and S-1 showed notable efficacy with manageable safety in the first-line treatment of advanced HER2-overexpressing GC/GEJC patients. These findings support further exploration in this context. Clinical trial information: NCT05586061 .

427P Conversion therapy of concurrent chemoradiotherapy combined with tislelizumab for unresectable gastric or gastroesophageal junction adenocarcinoma: A prospective, single-arm, phase II trial

427P Conversion therapy of concurrent chemoradiotherapy combined with tislelizumab for unresectable gastric or gastroesophageal junction adenocarcinoma: A prospective, single-arm, phase II trial

446P A prospective study for real-world data (RWD) of ramucirumab plus paclitaxel in patients with locally advanced unresectable or metastatic gastric or gastroesophageal junction adenocarcinoma (KCSG ST21-06)

446P A prospective study for real-world data (RWD) of ramucirumab plus paclitaxel in patients with locally advanced unresectable or metastatic gastric or gastroesophageal junction adenocarcinoma (KCSG ST21-06)

Chinese Medicine Prolongs Overall Survival of Chinese Patients with Advanced Gastric Cancer: Treatment Pattern and Survival Analysis of a 20-Year Real-World Study.

To describe the treatment patterns and survival status of advanced gastric cancer (AGC) in China in the past two decades, and objectively evaluate the impact of standardized Chinese medicine (CM) treatment on the survival of AGC patients. This multicenter registry designed and propensity score analysis study described the diagnosis characteristics, treatment-pattern development and survival status of AGC from 10 hospitals in China between January 1, 2000 and July 31, 2021. Overall survival (OS) was evaluated between non-CM cohort (standard medical treatment) and CM cohort (integrated standard CM treatment ≥3 months). Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were performed to adjust any difference in average outcomes for bias. A total of 2,001 patients histologically confirmed locally advanced and/or metastasis stomach and gastroesophageal junction adenocarcinoma were enrolled. Among them, 1,607 received systemic chemotherapy, 215 (10.74%) accepted molecular targeted therapy, 44 (2.2%) received checkpoint inhibitor therapy, and 769 (38.43%) received CM. Two-drug regimen was the main choice for first-line treatment, with fluoropyrimidine plus platinum as the most common regimen (530 cases, 60.09%). While 45.71% (16 cases) of patients with HER2 amplification received trastuzumab in first-line. The application of apatinib increased (33.33%) in third-line. The application of checkpoint inhibitors has increased since 2020. COX analysis showed that Lauren mixed type (P=0.017), cycles of first-line treatment >6 (P=0.000), CM (P=0.000), palliative gastrectomy (P=0.000), trastuzumab (P=0.011), and apatinib (P=0.008) were independent prognostic factors for the OS of AGC. After PSM and IPTW, the median OS of CM cohort and non-CM cohort was 18.17 and 12.45 months, respectively (P<0.001). In real-world practice for AGC in China, therapy choices consisted with guidelines. Two-drug regimen was the main first-line choice. Standardized CM treatment was an independent prognostic factor and could prolong the OS of Chinese patients with AGC. (Registration No. NCT02781285).

Use of artificial intelligence–based digital pathology to predict outcomes for immune checkpoint inhibitor therapy in advanced gastro-esophageal cancer.

4013 Background: Accurate prediction of response and survival outcomes with anti-PD-1/PD-L1 immune checkpoint inhibition (ICI) remains a significant challenge in gastro-esophageal cancers. In this study, we use an artificial intelligence (AI)-based single-cell analysis of digitized whole-slide H&amp;E images (WSIs) to predict objective response and survival benefit of ICI in two independent cohorts of gastro-esophageal cancer patients. Methods: WSIs were obtained from 82 ICI-treated advanced gastroesophageal cancer patients (gastric, esophageal, and gastro-esophageal junction adenocarcinoma and squamous cell carcinoma) at Stanford University for discovery, and 189 ICI-treated advanced gastric adenocarcinoma patients at Southern Medical University for external validation. Deep learning models were deployed for automated tumor area detection and segmentation of cell nuclei within WSIs. We developed a fully automated cell annotation approach by leveraging multiplex immunofluorescence and trained a deep learning model to classify nuclei into four cell types from H&amp;E (tumor cells, lymphocytes, neutrophils, and macrophages). A total of 66 features were computed to quantify cell composition and cell-cell interactions within the tumor microenvironment. Treatment outcomes were assessed using progression-free survival (PFS) and best objective response per the Response Evaluation Criteria in Solid Tumors (v1.1), with statistical significance reported at the 95% confidence level. Results: In the training cohort, a spatial feature characterizing lymphocyte and neutrophil interaction had the strongest association with PFS (hazard ratio = 0.44, 95% CI 0.24-0.79, P = 0.0046). In the validation cohort, the spatial biomarker positive population had significantly improved PFS compared to the spatial biomarker negative population (hazard ratio = 0.41, 95% CI 0.27-0.61, P &lt; 0.0001; median time to event: 19 months vs 9 months). For predicting objective response in the validation cohort, a multivariate model combining the spatial features achieved AUROC = 0.81 compared to AUROC = 0.65 for PD-L1 CPS (P = 0.0014), while combining the multivariate model with PD-L1 CPS achieved AUROC = 0.84. Conclusions: A single-cell computational pathology approachidentifies spatial biomarkers with predictive utility for determining ICI treatment outcomes in advanced gastro-esophageal cancer. Further validation of these findings is being pursued in additional cohorts.

Population based assessment of HER-2 and PD-L1 positivity in gastric and gastroesophageal junction adenocarcinomas in a Canadian population.

e16038 Background: Current standard of care for advanced gastric and gastroesophageal cancers combines systemic chemotherapy with either human epidermal growth factor receptor 2 (HER-2) or programmed death ligand 1 (PD-L1) targeting therapy. New data is emerging that for patients whose tumours are positive for both HER-2 overexpression and have a PD-L1 combined positive score (CPS) &gt;1%, combining all three treatment modalities results in superior outcomes. There is limited international data, and no Canadian data, exploring the frequency of patients who have tumours that are both HER-2 and PD-L1 positive who will be eligible for this novel treatment approach. Objective: To determine the proportion of patients in Nova Scotia with HER-2 positive gastric and GEJ adenocarcinomas who have a PD-L1 CPS score above established clinical thresholds. Methods: A retrospective review of PD-L1 and HER-2 status for all patients diagnosed with gastric and GEJ adenocarcinomas in Nova Scotia between June 3, 2022 and August 13, 2023 was completed. PD-L1 CPS was evaluated using the 28-8 assay and was considered positive if &gt;1%. HER-2 overexpression was evaluated by immunohistochemistry and in cases with equivocal expression, status was based on fluorescence in situ hybridization. Results: Over the study period, 56 cases of gastric and 42 cases of GEJ adenocarcinoma were identified for a total of 98 cases. The median age of the study population was 73 years (range 38 - 91). 73 patients (74%) were male and 25 patients (26%) were female. HER-2 expression was evaluated in 92 cases, and PD-L1 CPS was evaluated in 95 cases. 19 cases (21%) were HER-2 positive and 86 cases (91%) were PD-L1 positive. 17 HER-2 positive cases were also PD-L1 positive (89%). Conclusions: This study provides population level data in a Canadian context on patients with gastric and GEJ adenocarcinoma with respect to HER-2 overexpression and PD-L1 status. This data will be helpful in planning allocation of clinical and financial resources as a new standard of care for these patients is established.

SCR-A002, a novel FGFR2b-targeting antibody-drug-conjugate for solid tumors.

e15019 Background: FGFR2b (fibroblast growth factor receptor 2 IIIb), a transmembrane tyrosine kinase, is overexpressed in various cancers, including gastric, esophageal, breast, hepatocellular, pancreatic, ovary, uterine, cervical, endometrial, lung, colorectal cancers. Bemarituzumab (FPA144), an afucosylated humanized IgG1 monoclonal antibody targeting FGFR2b with enhanced ADCC activity, showed promising clinical efficacy in phase 2 study of FGFR2b-selected gastric or gastroesophageal junction adenocarcinoma. We have developed a potential first-in-class FGFR2b-targeting ADC (SCR-A002) at IND-enabling status, displaying significantly superior anti-tumor potency compared to Bemarituzumab. Methods: SCR-A002 is comprised of a humanized anti-FGFR2b IgG1 monoclonal antibody conjugated with proprietary TOPO1 inhibitor payload (DAR 8) via a cleavable linker. Anti-FGFR2b antibody was generated by immunization of FGFR2b protein in mice followed by hybridoma technique. Binding activity and cytotoxicity were assessed in FGFR2b+ tumor cell line. And anti-tumor efficacy was evaluated in several CDX and PDX models. Results: SCR-A002 could specifically bind to FGFR2b on cancer cells and be internalized, and the TOPO1 inhibitor could be cleaved intracellularly to kill the cancer cells potently in vitro. After single-dose administration of SCR-A002, tumor regression was achieved in different FGFR2b expression level CDX and PDX models, even with big-size tumor or Bemarituzumab resistance. Conclusions: SCR-A002 showed potent anti-tumor efficacy in preclinical data, which suggest that SCR-A002 is expected to provide a new treatment option as single agent or combo with SoC for patients with FGFR2b-overexpressing solid tumor.

Immune checkpoint inhibitor treatment in PD-L1-negative gastroesophageal cancer tumors.

e16062 Background: We aimed to investigate whether there is a subgroup of patients with gastroesophageal cancers who, despite having IHC-PD-L1 negative tumors, might still benefit from ICI treatment. Furthermore, the impact of ICI treatment on patients with tumors that are PD-L1 negative by IHC but exhibit high CD274 (PD-L1) expression remains undefined. Methods: 1,416 esophageal adenocarcinomas (EA), 486 esophageal squamous carcinomas (ES), 859 esophagogastric junction adenocarcinomas (EJA), and 1,613 gastric adenocarcinoma (GA) samples were analyzed using NGS of DNA (NextSeq, 592 genes and NovaSeq, WES) and RNA (NovaSeq, WTS) (Caris Life Sciences, Phx, AZ). PD-L1 IHC positivity was defined as &gt; 1% CPS (Agilent's 22c3). Correlation between PD-L1 CPS and CD274 expression (transcripts per million – TPM) were assessed by Spearman’s coefficient. Tumors were divided into CD274-H (high expression) and CD274-L (low expression) cohorts, representing the top 25% and bottom 25% of expression levels, respectively. Real-world overall survival (OS) data were obtained from insurance claims records and analyzed using Cox proportional hazards with hazard ratios (HR) and log-rank tests. Results: Weak correlations were observed between PD-L1 CPS and CD274 expression in adenocarcinoma histology tumors (EA: 0.374, EJA: 0.358, GA: 0.387), while a stronger correlation was found in squamous tumors (ES: 0.537). Median CD274 expression was significantly higher in PD-L1+ compared to PD-L1- ES tumors (2.65-fold) and in EA (1.68-fold), EJA (1.92-fold), and GA (1.96-fold) tumors (p &lt; 0.001). In PD-L1 IHC-negative ES, there was no association between CD274-H expression and OS (H 12.4 vs L 10.6 mo; HR 0.90, p = 0.48). However, in adenocarcinomas, CD274-H showed a slightly improved OS (12.8 vs 11.3 mo; HR 0.79, p &lt; 0.05). CD274-H trended towards worse post-Carboplatin/paclitaxel (CP) OS (ES: 13.8 vs 18.2 mo; HR 1.60; p = 0.22; Adenocarcinoma: 18.2 vs 27.4 mo; HR 1.50, p = 0.19). Interestingly, CD274-H was associated with improved post-CP/nivolumab survival in ES (96.5 vs 28 mo; HR 0.32; p = 0.047), with a similar but not statistically significant pattern in Adenocarcinoma EGC (Not Reached vs 30.2 mo; HR 0.39, p = 0.23). Furthermore, in CD274-L GEC, there was no difference in post-treatment survival with the addition of Nivolumab to CP (Squamous: 30 vs 18.2 mo; HR 0.91, p = 0.83; Adenocarcinoma: 30.2 vs 27.4 mo; HR 1.14; p = 0.76). In contrast, CD274-H showed improved survival with the addition of Nivolumab (Squamous: 96.5 mo vs 13.8 mo; HR 0.15; p = 0.01; Adenocarcinoma: NR vs 18.2 mo; HR 0.30; p = 0.08). Conclusions: High CD274 expression was associated with improved survival when Nivolumab was added to chemotherapy in patients with PD-L1-negative tumors. Further investigation is needed to confirm the potential benefits of Nivolumab treatment in gastroesophageal cancer patients with tumors that are PD-L1-negative by IHC but exhibit high mRNA expression.

497TiP Randomized phase II trial of trifluridine/tipiracil plus ramucirumab versus trifluridine/tipiracil for pre-treated patients with advanced gastric or gastroesophageal junction adenocarcinoma (RETRIEVE study, WJOG15822G)

497TiP Randomized phase II trial of trifluridine/tipiracil plus ramucirumab versus trifluridine/tipiracil for pre-treated patients with advanced gastric or gastroesophageal junction adenocarcinoma (RETRIEVE study, WJOG15822G)

Impact of immune checkpoint inhibitors on survival outcomes in advanced gastric cancer in Japan: A real-world analysis.

Nivolumab was approved for the treatment of advanced gastric cancer in 2017 in Japan. The aim of this study was to assess the impact of nivolumab in a real-world clinical setting. This single-institutional retrospective study included patients with advanced gastric or esophagogastric junction adenocarcinoma and a history of first-line chemotherapy with platinum-based doublet or triplet regimens between 2010 and 2020. To assess the impact of nivolumab on survival, the patients were divided based on the year of nivolumab approval into a pre-2017 (2010-2016) group and a post-2017 (2017-2020) group. From a total of 1918 patients, 1093 were excluded. There were 533 patients in the pre-2017 group and 292 in the post-2017 group. Immune checkpoint inhibitors were used significantly more often in the post-2017 group than in the pre-2017 group (8.6% vs. 47.9%). Median overall survival was significantly longer in the post-2017 group (16.9 vs. 13.9 months; hazard ratio [HR] 0.75, 95% confidence interval [CI] 0.63-0.90; p < 0.01). The proportion of patients transitioning to third-line treatment was higher in the post-2017 group than in the pre-2017 group (56.3% vs. 43.8%, p < 0.01). Median survival outcomes following progression on second-line treatment were significantly longer in the post-2017 group (4.3 vs. 3.2 months; HR 0.70, 95% CI 0.57-0.86; p < 0.01). The proportion of patients transitioning to third-line treatment and survival outcomes following progression on second-line treatment have improved since the approval of nivolumab. This drug might help to prolong overall survival in real-world practice.

68Ga-FAPI-04 positron emission tomography/computed tomography (PET/CT) for detecting occult peritoneal metastasisin locally advanced gastric cancer: A single-center prospective cohort study.

4081 Background: Occult peritoneal metastasis (OPM) is a common finding in patients diagnosed with advanced gastric cancer. Preoperative diagnosis of OPM is crucial for developing treatment strategies and for evaluating the prognosis of patients with locally advanced gastric cancer. To evaluate the accuracy of 68Ga-FAPI-04 PET/CT in diagnosing OPM in locally advanced gastric cancer. Methods: This was a prospective, observational, single-center, single-blind, cohort study. Patients with histologically proven locally advanced gastric or gastroesophageal junction adenocarcinoma on initial staging evaluation were recruited. Laparoscopic staging and cytological analysis of peritoneal washing served as reference standards for the final diagnosis. The primary outcome was the proportion of participants changing treatment strategy from curative to palliative treatment. Results: A total of 49 patients were recruited between November 2022 and July 2023 .Nine of the 49 patients were diagnosed with OPM following 68Ga-FAPI-04 PET/CT examinations. A total of 18.4% (n=9) of patients with locally advanced disease on initial staging evaluation by contrast-enhanced CT were upstaged to stage IV for peritoneal metastasis on 68Ga-FAPI-04 PET/CT. The sensitivity of 68Ga-FAPI-04 PET/CT in detecting OPM was 85.7%, and the specificity was 92.3%. The overall diagnostic accuracy of 68Ga-FAPI-04 PET/CT was 91.8%. Based on ROC curve analysis, the area under the curve (AUC) was 0.893 (95% CI: 0.734–1). Conclusions: The findings of this study suggest a significantly additional value of 68Ga-FAPI-04 PET/CT in detecting OPM. Thus, it would be useful to include 68Ga-FAPI-04 PET/CT in the guidelines for staging locally advanced gastric cancer, instead of laparoscopic staging. Clinical trial information: ChiCTR2300067591.

Fruquintinib plus paclitaxel versus placebo plus paclitaxel for gastric or gastroesophageal junction adenocarcinoma: the randomized phase 3 FRUTIGA trial.

The vascular endothelial growth factor pathway plays a key role in the pathogenesis of gastric cancer. In the multicenter, double-blind phase 3 FRUTIGA trial, 703 patients with advanced gastric or gastroesophageal junction adenocarcinoma who progressed on fluorouracil- and platinum-containing chemotherapy were randomized (1:1) to receive fruquintinib (an inhibitor of vascular endothelial growth factor receptor-1/2/3; 4 mg orally, once daily) or placebo for 3 weeks, followed by 1 week off, plus paclitaxel (80 mg/m2 intravenously on days 1/8/15 per cycle). The study results were positive as one of the dual primary endpoints, progression-free survival (PFS), was met (median PFS, 5.6 months in the fruquintinib arm versus 2.7 months in the placebo arm; hazard ratio 0.57; 95% confidence interval 0.48-0.68; P < 0.0001). The other dual primary endpoint, overall survival (OS), was not met (median OS, 9.6 months versus 8.4 months; hazard ratio 0.96, 95% confidence interval 0.81-1.13; P = 0.6064). The most common grade ≥3 adverse events were neutropenia, leukopenia and anemia. Fruquintinib plus paclitaxel as a second-line treatment significantly improved PFS, but not OS, in Chinese patients with advanced gastric or gastroesophageal junction adenocarcinoma and could potentially be another treatment option for these patients. ClinicalTrials.gov registration: NCT03223376 .

Risk factors and clinical significance of lower perigastric lymph node metastases in Siewert type II and III esophagogastric junction adenocarcinoma: a retrospective cohort study

BackgroundNo consensus has been concluded with regarding to the scope of lymph node (LN) dissection for Siewert type II and III adenocarcinoma of the esophagogastric junction (AEG). This study aimed to explore risk factors for lower perigastric LN (LPLN) metastases (including no. 4d, 5, 6, and 12a LN stations) and analyze the indications for LPLN dissection.MethodsIn total, 302 consecutive patients with Siewert type II and III AEG who underwent total gastrectomy (TG) were enrolled. The logistic regression model was used to perform uni- and multivariate analyses of risk factors for LPLN metastases. Kaplan–Meier curves were used for survival analysis, and log-rank tests were used for group comparisons. Basing on the guidelines of Japanese Gastric Cancer Association, the LN metastases (LNM) as well as the efficiency index (EI) of each LN station was further evaluated.ResultsThe independent risk factors for LPLN metastases in patients with Siewert type II and III AEG were distance from the esophagogastric junction (EGJ) to the distal end of the tumor (> 4.0 cm), preoperative carcinoembryonic antigen (CEA) ( +), pT4 stage, and HER-2 ( +). LPLN metastases was an independent risk factor for overall survival following TG. The LNM and EI of LPLN were 8.6% and 2.31%, respectively. The LNM of LPLN > 10% under the stratification of the distance from the EGJ to the distal end of the tumor (> 4.0 cm), pT4, preoperative CEA ( +), and HER-2 ( +) exhibited EI values of 3.55%, 2.09%, 2.51%, and 3.64%, respectively.ConclusionsLPLN metastases was a malignant factor for the prognosis of patients with Siewert type II and III AEG. For patients with preoperative CEA ( +), pT4 stage, HER-2 ( +), and the distance from the EGJ to the distal end of the tumor (> 4.0 cm), TG with LPLN dissection is prioritized for clinical recommendation.