Advanced Adenocarcinoma Research Articles

A phase II study of cadonilimab plus mFOLFIRINOX as induction therapy for locally advanced pancreatic adenocarcinoma (LAPC).

TPS4213 Background: Locally advanced pancreatic adenocarcinoma (LAPC) constitutes a significant proportion of pancreatic cancer, which ranks among the most lethal malignancies globally. Treatment options specifically tailored for LAPC patients (pts) are scarce, and chemotherapy alone yields limited efficacy. Various studies have provided supportive evidence for the synergistic effects of combining immunotherapy with chemotherapy in the context of pancreatic cancer. Cadonilimab, a novel recombinant humanized bispecific antibody, holds the capability to concurrently inhibit PD-1 and CTLA-4 pathways, thereby restoring T-cell immune response to the tumor. This study aims to assess the efficacy and safety of combining cadonilimab with modified FOLFIRINOX for the treatment of LAPC. Methods: This ongoing phase II trial is enrolling pts with histologically or cytologically confirmed unresectable LAPC who have an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0-1 and have not previously received systemic anti-tumor therapy. Eligible pts will be administered cadonilimab (6mg/kg, intravenous drip, Day 1, every 2 weeks) plus mFOLFIRINOX (oxaliplatin 85mg/m2, Day 2 + leucovorin 400mg/ m2, Day 2 + irinotecan 150mg/ m2, Day 2 + 5-fluorouracil 2,400mg/ m2, continuous infusion for 46 hours) for a total of 4 cycles (8 weeks). After the completion of every 4 treatment cycles, pts will undergo imaging examinations of tumor lesions. Pts will receive treatment continuously until surgical resection, disease progression, intolerable toxic reactions, initiation of new anticancer drug treatments, withdrawal from the study, death, or loss of follow-up. Following the 12th cycle of treatment, maintenance treatment will consist of capecitabine or S-1 in combination with cadonilimab. The primary endpoint of this study was the R0/R1 resection rate. The main secondary endpoints include the objective response rate (ORR) per RECIST 1.1, progression-free survival (PFS), overall survival (OS), and safety assessments. Additionally, pts will undergo peripheral blood next-generation sequencing (NGS) panel analysis before and after treatment to investigate the correlation between circulating tumor DNA (ctDNA) changes, surgical decisions, and prognosis. Enrollment is ongoing. Clinical trial information: NCT06153368 .

Envafolimab in combination with lenvatinib and albumin paclitaxel for previously treated advanced gastric/gastroesophageal junction adenocarcinoma: Preliminary analysis of a phase II, two-cohort study.

e16039 Background: The combination of first-line chemotherapy and PD-1 has emerged as a standard treatment, enhancing the efficacy in advanced gastric/gastroesophageal junction (GEJ) cancer. The efficacy of the combination of second-line chemotherapy and PD-1/PD-L1 remains unclear. This study aims to observe the efficacy of Envafolimab plus tyrosine kinase inhibitors (TKIs) and second-line chemotherapy in the treatment of patients with advanced GEJ adenocarcinoma. Methods: This prospective, open-label, phaseⅡ, two cohort study was conducted to assess the efficacy and safety of Envafolimab-based therapy in patients experiencing progression after initial first-line treatment. Eligible patients with HER2-negative, microsatellite stable (MSS), advanced GEJ adenocarcinoma were consecutively enrolled and assigned into cohort A or cohort B, according to whether they received PD-1 inhibitors in the first-line treatment. Patients in both cohorts received Envafolimab (200mg, hypodermic injection, days 1 and 15, Q4W) combined with Lenvatinib (8mg/12mg, po, once a day) and albumin paclitaxel (100mg/m2, IV, days 1, 8 and 15, Q4W, up to 6 cycles) until disease progression, unacceptable toxicity, or patients refusal to continue treatment. The primary endpoint was objective response rate(ORR) per iRECIST v1.1, and the secondary endpoints included disease control rate (DCR), progression free survival (PFS), overall survival (OS) and safety. The efficacy and safety data in this analysis were from patients in cohort A who previously failed in first-line chemotherapy and did not receive PD-1 or PD-L1 inhibitors ever. Results: From October 2022 to June 2023, cohort A enrolled 16 patients, and 15 of them were evaluable for efficacy analysis. The average age was 58.87 ±11.81 years, 80% patients were male. 6 patients had been tested for PD-L1 status, of which 1 (16.7%) was positive and 5 (83.3%) were negative. As of Jan29, 2024, the median follow-up was 10.6 months (95%CI = 8.67-12.53), the median number of treatment cycles was 7 cycles (IQR: 5, 8). Based on the iRECIST v1.1, the ORR was 60.00% (90% CI = 35.96%-80.91%), the DCR was 100.00% (90% CI = 81.90%-100.00%). The median PFS (mPFS) was 8.23 months (90% CI =6.27-8.61), and the median OS (mOS) was 10.6 months (90% CI =8.79-12.15). Overall incidences of adverse events (AEs) of any grade was 100%, and 75.00% (n = 12) had ≥ grade 3 AEs during treatment. Most treatment-related adverse events (TRAEs) of grade ≥3 included neutrophil count (56.25%), decreased leukocyte count (37.5%). Conclusions: In patients of advanced gastric cancer who have not previously received PD-1/PD-L1 inhibitors, this second-line combination therapy demonstrates promising preliminary effects. Clinical trial information: NCT06030934 .

Social factors in the receipt of treatment for locally advanced esophageal cancer.

e16093 Background: Treatment for locally advanced esophageal cancer consists of chemoradiation (chemoRT) followed by esophagectomy. Studies have suggested Black patients were less likely to undergo surgery for esophageal cancer with inferior survival rates, attributing this to differences in access to surgery. These studies have not always accounted for differences in the natural history of adenocarcinoma and squamous cell carcinoma, which have strong racial correlations and different rates of surgical resection. The current study examined outcomes and patterns of care for patients with locally advanced esophageal cancer, both adenocarcinoma and squamous cell carcinoma, in relation to their sociodemographic characteristics. Methods: Patients with clinical stage T2-4, N0-2, and M0 adenocarcinoma or squamous cell carcinoma of the mid or distal esophagus diagnosed between 2010-2021 were included from 11 hospitals across our healthcare system. Treatment decision-points included receipt of chemoRT, unresectable disease after chemoRT defined by metastatic disease or upper mediastinal lymphadenopathy, and receipt of surgery stratified by histology. Age, race, sex, insurance status, socioeconomic status measured by social deprivation index (SDI), and outcome data were collected. Chi-squared test was used for categorical variables and Kruskal-Wallis for continuous variables. Results: 513 patients were included, of whom 472 patients underwent chemoRT (366 adenocarcinoma, 106 squamous cell). Female patients (n =97) were less likely to undergo chemoRT (84% vs. 94%, p = 0.003). Patients without insurance were less likely to undergo chemoRT (86% vs 93%, p = 0.023). After completing chemoRT, 419 patients (82%) were resectable. Surgery was performed in 262/330 patients (79%) with adenocarcinoma and 38/89 patients (43%) with squamous cell carcinoma, reflecting the differences in natural history by histology. Among 330 patients with resectable adenocarcinoma, higher SDI was associated with a lower rate of surgery, while there was no difference in the receipt of surgery based on sex, race or insurance status. There were no detectable social factors associated with receipt of surgery for squamous cell carcinoma. Conclusions: Within our healthcare system, female and Medicaid/uninsured patients are less likely to undergo chemoRT for locally advanced esophageal cancer. Further studies are needed to evaluate whether sex-specific bias plays a role in the receipt of chemoRT. Among patients with resectable locally advanced esophageal adenocarcinoma treated with chemoRT, those with high SDI are less likely to undergo surgery. Further studies are needed to assess which component factors of socioeconomic status most impact the receipt of surgery so they can be targeted. The previous findings that race impacts treatment of locally advanced esophageal cancer are not seen in our healthcare system when accounting for histology.

Safety and efficacy of IBI343 (anti-claudin18.2 antibody-drug conjugate) in patients with advanced pancreatic ductal adenocarcinoma or biliary tract cancer: Preliminary results from a phase 1 study.

3037 Background: Prognosis for advanced pancreatic ductal adenocarcinoma (PDAC) and biliary tract cancer (BTC) remains poor, with limited treatment options available. Expression of claudin18.2 (CLDN18.2) has emerged as a potential target for anti-cancer treatment. Herein, we report preliminary safety and efficacy results of IBI343, an antibody-drug conjugate (ADC) consisting of anti-CLDN18.2 monoclonal antibody conjugated to exatecan (topoisomerase I inhibitor), in patients (pts) with advanced PDAC or BTC in a phase 1 study. Methods: Eligible pts who failed or were intolerant to standard treatment were enrolled. IBI343 were intravenously administered at 6 mg/kg or 8 mg/kg Q3W. In dose escalation, pts were enrolled regardless of CLDN18.2 expression. In dose expansion, pts were required to have CLDN18.2 expression ≥40% (1+/2+/3+ staining intensity by immunohistochemistry). Primary endpoint was safety. Secondary endpoints included objective response rate (ORR), disease control rate (DCR), duration of response (DoR) and progression free survival (PFS) assessed by investigator per RECIST v1.1. Results: As of December 19, 2023, 35 pts (1 pt in dose escalation and 34 pts in dose expansion) were enrolled from China and Australia (males: 57.1%, median age: 58.0 years, ECOG PS 1: 71.4%, stage IV: 91.4%, median lines of prior treatment: 2) including 28 PDAC pts and 7 BTC pts. Pts received IBI343 at 6 mg/kg (n=17) or 8 mg/kg (n=18). Median duration of treatment was 7.0 weeks (range: 3.0-23.6) with 23 (65.7%) pts still on treatment. In all pts, treatment-related adverse events (TRAEs) occurred in 28 (80.0%) pts including grade ≥3 TRAEs in 9 (25.7%) pts. Common TRAEs (≥20%) were anemia (42.9%), neutrophil count decreased (28.6%), nausea (25.7%), vomiting (25.7%) and white blood cell count decreased (22.9%). Serious TRAEs occurred in 4 (11.4%) pts. TRAEs leading to dose interruption and treatment discontinuation occurred in 7 (20.0%) pts and 1 (2.9%) pt respectively. No TRAE led to death. Safety profiles of IBI343 in PDAC and BTC were comparable with the whole study cohort and no new safety signal was observed. As of January 15, 2024, 25 pts at 6 mg/kg and 8 mg/kg were efficacy evaluable. Partial response (PR) was observed in 7 pts (5 PDAC and 2 BTC). The ORR was 28.0% (95%CI: 12.1-49.4) and DCR was 80.0% (95%CI: 59.3-93.2). In evaluable pts at 6 mg/kg with CLDN18.2 expression ≥60% (1+/2+/3+, n=13), 5 pts had PR with ORR of 38.5% (95%CI: 13.9-68.4) and DCR of 84.6% (95%CI: 54.6-98.1). Among 10 PDAC pts in this subgroup, ORR was 40% (95%CI: 12.2-73.8). DoR and PFS data were immature. More updated data on safety and efficacy will be presented at the meeting. Conclusions: IBI343 was well tolerated with favorable safety profiles and encouraging efficacy in CLDN18.2-positive PDAC and BTC. Clinical trial information: NCT05458219 .

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 .

Efficacy of chemotherapy followed by chemoradiation versus initial chemoradiation as part of the total neoadjuvant therapy for patients with locally advanced rectal cancer: An NCDB analysis.

e15629 Background: Results from multiple trials lead to modern management for locally advanced rectal cancer, with total neoadjuvant therapy (TNT) followed by surgery. However, the best sequence of different treatment modalities is unclear. Methods: We used the National Cancer Database (NCDB) to identify patients with locally advanced rectal adenocarcinoma. We divided patients into different categories based on the timing of chemo and radiation therapy relative to surgery. We used chi-square and Wilcoxon rank test for unadjusted comparison. To compare treatment efficacy with initial chemotherapy to concurrent chemoradiation in downstaging (clinical to pathological stage), we used a linear mixed effect model (LME) with adjustments on age, sex, race, facility type, and year of diagnosis. Also, we evaluated the probability of having positive lymph nodes in the pathological specimen (N+) in the multivariable logistic regression model with adjustment on the clinical stage in addition to the previously mentioned variables. All analyses were done using R 4.6.2. Results: A total of 100509 patients were identified. Only 695 patients received six cycles of neoadjuvant chemotherapy before concurrent chemoradiation (TNT chemotherapy), and 8677 patients received upfront radiation therapy with neoadjuvant chemotherapy administered within 12 weeks of neoadjuvant radiation therapy (TNT radiation). Patients whose start date of chemotherapy or radiation after surgery were excluded. The median age of participants was 63 (IQR = 54-63), and 83% were white. Patients who had TNT chemotherapy were younger (56.4 VS 59.5, P-value &lt; 0.01), had clinically and pathologically advanced stage (IIIB, IIIC) compared to TNT radiation (64%VS 37% and 33%VS 29%, P-value &lt; 0.01). Patients who received TNT radiation had an upgrade in their pathological stage compared to their clinical stage by 0.67 points in the LME (P value &lt; 0.01). In multivariable logistic regression. TNT chemotherapy had a 17% lower risk of (N+) with an OR of 0.83 (0.95 CI 0.59-1.16). However, it was not statistically significant. The two groups had no difference in OS, with a median OS of 137 months (0.95 CI 110 -NR) and 143 (0.95 CI 137-151), respectively. Conclusions: Upfront chemotherapy before starting chemoradiation could be associated with more significant downstaging. Future trials to validate our finding is warranted. [Table: see text] [Table: see text]

494TiP Efficacy and safety of cadonilimab and COX-2 inhibitor combined with oxaliplatin and capecitabine (XELOX) in perioperative treatment for locally advanced resectable gastric adenocarcinoma: A prospective, single-center, randomized, phase II trial

494TiP Efficacy and safety of cadonilimab and COX-2 inhibitor combined with oxaliplatin and capecitabine (XELOX) in perioperative treatment for locally advanced resectable gastric adenocarcinoma: A prospective, single-center, randomized, phase II trial

A phase II multicenter study of enfortumab vedotin with or without pembrolizumab in rare genitourinary tumors (E-VIRTUE).

TPS4628 Background: Enfortumab vedotin (EV) is an antibody-drug conjugate (ADC) targeting nectin-4 with a monomethyl auristatin E (MMAE) payload, a potent microtubule inhibitor. It is standard of care (SOC) in metastatic urothelial carcinoma in combination with pembrolizumab in untreated patients and as monotherapy in post-chemotherapy, post-immune checkpoint blockade (ICB) patients. Nectin-4 expression has been retrospectively observed in 66.7-100% of urinary tract adenocarcinoma, 70-100% of urinary tract squamous cell carcinoma (SCC) (Case et al., 2022; Hoffman-Censits et al., 2021) and 36% of testicular germ cell tumors (GCTs) (The Human Protein Atlas). Metastatic urinary tract adenocarcinoma and SCC, and treatment refractory GCTs do not have an established SOC. Given the known nectin-4 expression, we hypothesize that EV with or without pembrolizumab will be active in these rare GU tumors. Methods: E-VIRTUE is an open-label, non-randomized, Phase 2 multicenter study. Eligible patients must have locally advanced or metastatic urinary tract pure adenocarcinoma, urinary tract pure SCC or refractory GCTs and have measurable disease by RECIST 1.1. Patients may have received any number of lines of prior systemic therapy except EV or other MMAE-based ADCs, and GCT patients must be refractory to all curative SOC treatments. Each histology will have an ICB-naïve and post anti-PD-1/PD-L1 ICB cohort: ICB-naïve patients will be given EV 1.25 mg/kg (maximum 125 mg) on Days 1 and 8 and pembrolizumab 200 mg on Day 1 of 21-day cycles, and post ICB patients will be given EV 1.25 mg/kg (maximum 125 mg) on Days 1, 8 and 15 of 28-day cycles. EV will be given for up to 5 years and pembrolizumab will be given for up to 2 years, or until progressive disease (PD) or unacceptable toxicity. Patients who stop pembrolizumab after achieving a complete response may resume it for 1 year after developing PD. The primary objective is to evaluate the objective response rate (ORR) in all cohorts. Secondary objectives include safety, progression-free survival (PFS) and overall survival (OS). The initial 6 cohorts will each be evaluated with exploratory intent. With 10 patients in each cohort, an exact binomial test with a 10% one-sided significance level will have 85.3% power to detect the difference between a very low (5%) ORR and a higher (30%) ORR. If there are ≥2/10 objective responses in any cohort, activity will be demonstrated. Additional histologies may be added after nectin-4 data emerges to justify their inclusion. Exploratory objectives include estimating the level of nectin-4 expression for each histology, performing DNA and RNA sequencing of tumor and blood samples, and observing changes in levels of circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) with treatment and disease status. Clinical trial registration NCT06041503. Clinical trial information: NCT06041503 .

Meta-analysis comparing the incidence of serious adverse events, overall survival, and progression-free survival in patients with pancreatic adenocarcinoma harboring unresectable tumors treated with modified FOLFIRINOX or FOLFIRINOX regimen.

e16318 Background: The evolution of first-line treatment for advanced pancreatic adenocarcinoma (PDAC) from Gemcitabine-based therapies to FOLFIRINOX-based regimens (fluorouracil, leucovorin, irinotecan, oxaliplatin) have demonstrated significant improvements in survival outcomes, however, this was associated with increased side effects such as neuropathy, fatigue, and diarrhea due to its heightened potency. Modified versions of FOLFIRINOX (mFOLFIRINOX) have since been developed with lower doses and longer breaks between cycles to manage side effects. Methods: To systematically test the efficacy and side effects of mFOLIFINOX treatment, we conducted a meta-analysis relating FOLFIRINOX treatment with modified FOLFIROX on the frequency of Grade 3 or 4 adverse events reported in published literature (9 studies), and Serious Adverse Events (SAE) recorded from clinical trials (17 arms accessed from clinicaltrials.gov) in PDAC patients with unresectable tumors. Results: For adverse events occurring in greater than 10% of patients, significant reductions in the frequency of patients experiencing the following events were observed in PDAC patients treated with mFOLFIRINOX: Neutropenia (29.31 % (226/771 patients across 8 arms) versus 18.8% (144/766 across 8 arms; Fisher Exact test, 2-tailed, P &lt; 0.001)), Anorexia (18.57 % (44/237 across 3 arms) versus 5.39% (18/334 across 3 arms); P &lt; 0.001), Peripheral sensory neuropathy (10.63 % (27/254 across 2 arms) versus 3.45% (4/116 across 2 arms); P = 0.025)), and Fatigue (10.57 % (83/785 across 9 arms) versus 6.77% (55/812 across 8 arms); P = 0.007)). Examination of 8 studies (N = 635) for PDAC patients treated with FOLFIRINOX exhibited a median OS time of 11.37 (Range = 10.07 - 13.9) months. Patients treated with mFOLFIRINOX (N = 475) exhibited a median OS time of 12.8 (10.2 - 14.4) months (Two-sample Wilcoxon test, P = 0.372). Conclusions: In conclusion, modified FOLFIRINOX has maintained similar efficacy while reducing severe adverse events, making it more tolerable for adjuvant treatment after surgery.

Exploring racial disparities and tumor characteristics of CA19-9 producer and non-producer among patients with advanced pancreatic ductal adenocarcinoma (PDAC): Implications for survival and personalized treatment strategies.

e16309 Background: Despite substantial progress in cancer treatment, PDAC remains a highly lethal disease. CA19-9 plays a crucial role in PDAC diagnosis and therapeutic response assessment. We aimed to evaluate racial differences, tumor characteristics, and outcomes between CA19-9 non-producers and producers among advanced PDAC patients (pts) at an academic teaching hospital. Methods: A retrospective analysis was conducted in patients with unresectable or metastatic PDAC treated at Mount Sinai Health System between January 2012 and December 2021. Pts were categorized into two groups based on CA19-9 levels, using a threshold of 37 U/mL: CA19-9 non-producers (≤37 U/mL) and CA19-9 producers ( &gt; 37 U/mL). Demographic and clinical data were compared between the two groups, and the association between CA19-9 levels and overall survival (OS) was assessed using Kaplan-Meier estimates and multivariable Cox proportional hazards regression models. Results: A total of 238 pts were included in the analysis, with a median age of 67 years and a balanced gender distribution (52% male). The cohort comprised locally advanced (29.8%) and metastatic (70.2%) cases, with a diverse ethnic composition including non-Hispanic whites (37%), non-Hispanic blacks (25%), and Hispanics (18%). Among the pts, 23.5% were CA19-9 non-producers, while 76.5% were CA19-9 producers. Significant racial differences were observed, with non-Hispanic blacks more likely to be CA19-9 non-producers compared to non-Hispanic whites ( P&lt; 0.001). However, no statistically significant differences were found in age, smoking status, tumor location, size, or site of metastasis between the two groups. Median overall survival (OS) was 13m for CA19-9 producers and 16m for non-producers, but this difference was not statistically significant in both univariate and multivariate analyses (HR 1.09, 95% CI 0.74-1.58, P = 0.66; HR 1.06, 95% CI 0.72-1.58, P 0.8). Hispanic ethnicity was correlated with improved OS (HR 0.59, 95% CI 0.36-0.95, P = 0.029), while larger tumor size predicted worse OS (HR 1.17, P &lt; 0.001). Conclusions: This study highlights racial disparities in CA19-9 production among locally advanced and metastatic PDAC patients. Despite observed differences, CA19-9 levels alone did not emerge as a statistically significant predictor of OS. Future research should delve deeper into the racial disparities observed in CA19-9 production, exploring underlying biological mechanisms and potential implications for diagnostic and therapeutic approaches as this could refine our understanding of PDAC, facilitating targeted interventions for improved patient outcomes.

Phase II randomized clinical trial comparing albumin-bound docetaxel vs. docetaxel in patients with previously treated advanced gastric or gastroesophageal junction adenocarcinoma.

e16018 Background: Albumin-bound docetaxel (HB1801) is a new kind of taxane and has many advantages compared with docetaxel. Previous phase I study has demonstrated that HB1801 showed preliminary efficacy in patients with gastric cancer. Here we presented the efficacy and safety of HB1801 in patients with gastric or gastroesophageal junction (G/GEJ) adenocarcinoma. Methods: In this phase II study, eligible patients were aged 18-75 years with histologically confirmed G/GEJ adenocarcinoma, who progressed on at least first line of combined chemotherapy of platinum and fluorouracil. Patients were randomized (1:1) to receive HB1801 (100 mg/m2) or docetaxel (Taxotere, 75 mg/m2) administered every 3 weeks by intravenous infusion. Stratified factors included previous treatment with immunotherapy (yes or no) and ECOG PS (0 or 1). Primary endpoint was progression free survival (PFS) per RECIST version 1.1 assessed by independent review committee. Secondary endpoints included overall survival, objective response rate (ORR), disease control rate (DCR), duration of response (DOR) and safety. Results: As of December 31, 2023, 125 patients were enrolled and randomized to HB1801group ( n= 63) or docetaxel group ( n= 62). The two groups were comparable on baseline characteristics. Overall, the median age was 59.0 (range 27-75) years, 98 (78.4%) patients had ECOG PS of 1. 73 (58.4%), 7 (5.6%) and 6 (4.8%) patients had received previous treatment with immunotherapy, antiangiogenic agents and anti-HER2 therapy. 45 patients in HB1801 group and 47 patients in docetaxel group were evaluable for efficacy. ORR and DCR were 24.4% (11 PRs, 95%CI 12.88-39.54) and 57.8% (15SDs, 95%CI 42.15-72.34) for HB1801 group, 14.9% (1 CR+6 PRs, 95%CI 6.20-28.31) and 46.8% (15 SDs, 95%CI 32.11-61.92) for docetaxel group. Patients in HB1801 group had a numerically longer DOR than those docetaxel group (median DOR: 2.9 months (95% CI 1.41-NA) vs 1.5 months (95% CI 1.41-NA)). Treatment-related adverse events (TRAEs) occurred in 87.1% of patients receiving HB1801, and 82.3% of patients receiving docetaxel. Alopecia (38.7% vs. 37.1%) and anemia (33.9% vs 35.5%) were the most predominant TRAEs in both groups, fatigue (38.7% vs 17.7%), hypoalbuminemia (27.4% vs 8.1%), decreased appetite (17.7% vs 12.9%), peripheral edema (16.1% vs 4.8%) were also observed in HB1801 group and docetaxel group. 14 patients (22.6%) in HB1801 group and 15 patients (24.2%) in docetaxel group experienced ≥grade 3 TRAEs, with the most common being anemia, leukopenia, decreased appetite, fatigue and lymphopenia. There were no treatment-related deaths. No new safety signal was observed in HB1801 group. Conclusions: These preliminary results suggest that HB1801 had manageable safety profile and promising efficacy in patients with previously treated advanced G/GEJ cancer. Clinical trial information: NCT05705635 .

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.

357P Single-center analysis of DNA damage repair (DDR) germline mutations (GM) in patients (pts) with advanced pancreatic ductal adenocarcinoma (aPDAC)

357P Single-center analysis of DNA damage repair (DDR) germline mutations (GM) in patients (pts) with advanced pancreatic ductal adenocarcinoma (aPDAC)

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.

Phase 2 randomized study of rintatolimod following FOLFIRINOX in patients with locally advanced pancreatic adenocarcinoma.

TPS4214 Background: The immunosuppressive microenvironment of pancreatic ductal adenocarcinoma (PDAC) is a driver of its lethality and resistance to immunotherapy. Strategies which modulate the immunosuppressive milieu have the potential to improve the anti-tumor response and improve outcomes in patients with PDAC. Rintatolimod is a synthetic double-stranded RNA molecule that activates the toll-like receptor 3 (TLR3) present on dendritic cells, B-cells, natural killer cells and pancreatic epithelial cells. TLR3 stimulation may increase cytotoxic T-cell activity in PDAC through dendritic cell maturation, antigen priming and downstream proliferation of cytotoxic T-cells. Twenty-seven patients were treated with rintatolimod in a single center Named Patient Program at Erasmus University Medical Center in Rotterdam between January 2017 and February 2019. All had locally advanced or metastatic PDAC which had not progressed on FOLFIRINOX (median 8 cycles). Maintenance rintatolimod, administered intravenously twice weekly for up to 18 weeks, was generally well tolerated. The most common toxicities were grade 1-2 myalgia (30%), chills (52%) and fatigue (30%); no toxicities ≥ grade 3 were observed. Progression-free and overall survival (from cycle 1 FOLFIRINOX) were 13 and 19 months. Methods: This is a phase 2 randomized, open-label, multicenter clinical trial. The primary objective is to assess the efficacy of rintatolimod compared to observation in subjects with locally advanced PDAC which has not progressed after FOLFIRINOX. Eligible patients have completed at least 4 months of FOLFIRINOX, have no evidence of progressive disease, have measurable disease by RECIST v1.1, Karnofsky Performance Status ≥80 and have adequate organ function. Subjects with resected PDAC or metastatic disease are not eligible. Subjects are randomized 2:1 to rintatolimod vs. observation. Rintatolimod is administered intravenously twice weekly until disease progression in the experimental arm. Cross-sectional imaging is performed every 8 weeks in both arms. The primary endpoint is progression-free survival, as assessed by the investigator. Secondary endpoints include overall survival, objective response rate, duration of response and safety, as assessed by CTCAE v5.0. Exploratory endpoints include quality of life and changes in immune cell composition and T-cell response in the peripheral blood to characterize the immunomodulatory effects of rintatolimod. The planned sample size is 90 subjects. The final analysis will be performed after 64 events (disease progression or death) have been observed. The study is powered to detect a hazard ratio of 0.47 for median PFS with 80% power and significance level of 5%. Clinical trial information: NCT05494697 .

Chemotherapy with or without surgery for locally advanced or borderline resectable pancreatic ductal adenocarcinoma: A retrospective multicenter international study.

e16352 Background: Current clinical guidelines recommend surgery for patients with locally advanced (LA)/borderline resectable (BR) pancreatic ductal adenocarcinoma (PDAC) who achieve disease control after induction therapy. However, the additional survival benefit of surgery in these patients is unknown. Methods: In this multicenter international retrospective cohort study, consecutive patients with BR/LA PDAC who achieved disease control after three to six months of induction therapy (combination chemotherapy or chemoradiotherapy) between January 2014 and July 2021 were retrospectively identified at 8 centers in Germany and Italy. Resectability status was determined by consensus in a multidisciplinary tumor board based on imaging findings, serum CA19-9, performance status and clinical response. Patient characteristics, progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Cox regression analysis was used to compare survival data. Results: A total of 138 patients who achieved disease control with induction therapy were analyzed. The median age at diagnosis was 66 years (range 45-82) and 43% of patients were female. 73 patients underwent surgery and 65 patients did not (median age 64 and 69 years, respectively, p = 0.02). Median OS was 20.0 months (95%CI 16.1-23.8) in the surgery group and 18.0 months (95%CI 13.6-22.4) in the nonsurgery group (hazard ratio for death, 0.90; 95%CI, 0.63 to 1.29, p = 0.57). Median PFS was 14.0 months (95%CI 8.9-19.1) in the surgery group and 15.0 months (95%CI 11.7-18.3) in the nonsurgery group (hazard ratio for disease progression, 1.04; 95%CI, 73 to 1,47, p = 0.83). The 2-year survival rates in the surgery and nonsurgery groups were 32.9% and 40.0%, respectively, with an overall odds ratio of 0.74 (95% CI: 0.37-1.47). Conclusions: In our multicenter international retrospective analysis, additional surgery did not confer a survival advantage to patients with BR/LA PDAC who achieved disease control with induction therapy.

Neoadjuvant serplulimab in combination with concurrent chemoradiotherapy for locally advanced, resectable esophagogastric junction adenocarcinoma.

e16103 Background: Surgery combined with perioperative therapy was recommended as standard treatment for patients with locally advanced esophagogastric junction (EGJ) adenocarcinoma, but the survival rate was still poor. Immunotherapy has shown antitumor activity and an acceptable safety profile in advanced EGJ cancer. The aim of this study was to evaluate the efficacy and safety of neoadjuvant Serplulimab combined with concurrent chemoradiotherapy in previously untreated locally advanced resectable EGJ adenocarcinoma. Methods: Eligible patients with resectable EGJ(Siewert Type II and Type III, Siewert classification 2000)adenocarcinoma stage cT3-4 or N+ were enrolled. Patients received neoadjuvant Serplulimab (300mg on day 1) plus SOX(oxaliplatin at 130mg/㎡on day 1; TS1 40-60mg two times per day on D1-D14, Q3W) in first cycle, followed by Serplulimab (300mg on day 1) combined with concurrent chemoradiotherapy (Reduced SOX regimen: oxaliplatin at 100mg/㎡on day 1, TS1 40-60mg two times per day on D1-D14, Q3W; Radiotherapy dose:45Gy in 25f) in second and third cycle. The patient finished the preoperative treatment and rested for 6-8 weeks for surgery. The primary endpoint was pathological complete response (pCR) rate. Secondary endpoints were major pathological response(MPR) rate, R0 resection rate, objective response rate(ORR), disease-free survival(DFS), overall survival(OS), and toxicity. Results: From March 8, 2023 to January 31,2024,15 patients were enrolled. Nine patients completed neoadjuvant therapy. Eight of these patients underwent radical surgical resection. One out of nine achieved a confirmed pathological complete response (pCR) after three cycles of neoadjuvant treatment. Additionally, two out of nine patients achieved major pathological response(MPR). So, the pCR rate was 11.1%, and the MPR rate was 22.2%. The Tumor and Lymph Nodes downstaging rates are 62.5% and 87.5%, respectively. The median DFS and OS were not reached. In terms of safety, fifteen patients who received at least one cycle of neoadjuvant therapy were included. The most common treatment-related adverse events(TRAE) across all grades were nausea/vomiting(6/15), anorexia(5/15), thrombocytopenia(4/15), and fatigue(4/15). Four patients (26.7%) had grade≥3 adverse events during preoperative therapy, with thrombocytopenia(3/15) and hepatic veno-occlusive disease(1/15). Immune-related adverse reactions(irAE) included myositis(1/15) and rash(1/15), both were grade 1. No grade 4 or higher TRAEs were observed. Conclusions: Initial benefits were demonstrated when using Serplulimab with concurrent chemoradiotherapy for the treatment of locally advanced, resectable EGJ adenocarcinoma patients. The efficacy and safety of Serplulimab with chemoradiotherapy will be further investigated in this trial later. Clinical trial information: NCT05918419 .

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

Efficacy and safety of sitagliptin, in combination with gemcitabine plus nab-paclitaxel (GnP) in patients with previously untreated advanced pancreatic ductal adenocarcinoma (PDAC).

e16329 Background: Chemoresistance is the main reason for the poor prognosis of pancreatic ductal adenocarcinoma (PDAC). Thus, there is an urgent need to identify new targets and compounds to overcome chemotherapeutic resistance. Methods: The high-throughput virtual drug screening, molecular docking analysis and organoid biobank-based drug screening were performed to identify the candidates to efficiently overcome chemotherapy resistance. In vitro and in vivo PDOs, PDXs and KPC GEMM models were used to evaluate the effects of the compounds. Spatial single cell RNA-sequence, spatial metabolomics and proteomics were employed to elucidate the mechanism. Additionally, an ongoing open-label, randomized, single-arm, single-center phase 2 investigator-initiated clinical trial (NCT05947825) is investigating the efficacy and safety of the candidate in sensitizing gemcitabine plus nab-paclitaxel (GnP) in previously untreated advanced PDAC patients. Objective tumor responses were assessed according to RECIST1.1 criteria and any adverse events were graded using CTCAE 5.0. The primary endpoint was progression-free survival (PFS), and secondary endpoints included objective response rate (ORR), disease control rate (DCR), overall survival (OS), and treatment-emergent adverse events (TEAEs). Results: High-throughput drug screening of chemotherapy-resistant PDOs identified Sitagliptin that could significantly induce the degradation of RRM1/RRM2 in a ubiquitin proteasome-dependent manner and further result in unrestrained pyrimidine biosynthesis and alleviation of replication stress. In vitro and in vivo assays confirmed that Sitagliptin could synergistically enhance the ability of GnP regimen to suppress PDAC progression. In the phase 2 study (NCT05947825), previously untreated advanced PDAC received Sitagliptin, 100mg/qd and gemcitabine (G, 1000mg/m2 )plus nab-paclitaxel (nP, 125 mg/m2 )on Days 1 and 8 in a 21-day cycle. Till February 1, 2024, 12 patients with ECOG 0 to 2 have been enrolled in the study. The primary endpoint has not been reached. Among the 8 evaluable patients, 3 showed partial responses and 5 had stable diseases. The objective response rate (ORR) and disease control rate (DCR) were 37.5% and 100% respectively. There were no instances of treatment-related death in this study. The most common treatment-emergent adverse events (TEAEs) were decreased white blood cells and fatigue. One patient experience skin rash. Conclusions: Sitagliptin could effectively improve efficacy of GnP regimen by suppressing RRM1/RRM2-mediated pyrimidine metabolism. Sitagliptin plus GnP regimen is a feasible regimen with a manageable safety profile. Sitagliptin in combination with GnP regimen shows encouraging antitumor activity in PDAC, meriting continued development. Clinical trial information: NCT05947825 .