Ji, Yan

4213 Background: Elraglusib (9-ING-41), a glycogen synthase kinase-3β (GSK-3β) inhibitor, has multimodal antitumor activity. In the international, open-label, randomized phase 2 1801 Part 3B study, elraglusib plus gemcitabine/nab-paclitaxel (GnP) was evaluated in previously untreated metastatic pancreatic ductal adenocarcinoma (mPDAC), with patients randomized 2:1 to weekly elraglusib/GnP or GnP alone. Primary endpoints were median overall survival (mOS) and 1-year survival. The GnP control arm demonstrated shorter mOS than contemporary randomized trials (7.2 months vs 9.2 months in NAPOLI-3 and 9.7 months in PASS-01), driven by higher early mortality (0–2 months: 23.1% vs 10.1% in NAPOLI-3). Given balanced randomization, similar early mortality was inferred in the elraglusib/GnP arm, prompting post-hoc analyses to contextualize efficacy and identify factors associated with early death. Methods: Efficacy and safety were summarized descriptively. Time-to-event endpoints were analyzed using Kaplan–Meier estimates, log-rank testing, and Cox proportional hazards models. Response rates were compared using the Cochran–Mantel–Haenszel test. Post-hoc subgroup, sensitivity, and machine-learning–based multivariate analyses explored clinical, demographic, and biomarker correlates of survival and early mortality. Results: In the full randomized population (elraglusib/GnP n=155; GnP n=78), elraglusib/GnP improved mOS by 2.9 months versus GnP (10.1 vs 7.2 months; HR 0.62; 95% CI 0.46–0.84; p=0.01), with 1-year survival rates of 44.1% versus 22.3%. Among patients receiving ≥1 full treatment cycle, mOS was 12.5 months with elraglusib/GnP and 8.5 months with GnP, comparable to contemporary registrational trials. Across multiple post-hoc sensitivity analyses—including evaluable patients, those matched to NAPOLI-3 baseline tumor burden, patients treated in the EU (early mortality 4%), and those achieving ≥20% CA19-9 decline within the first 1–2 cycles—elraglusib/GnP consistently demonstrated a ≥4-month OS advantage. Early death was associated with low baseline albumin (<3 g/dL), high CA19-9 (>800 U/mL), high tumor burden, and KRAS, TP53, and CDKN2A co-mutations. Conclusions: The elevated early mortality in the GnP control arm reflects enrollment of a heterogeneous, real-world mPDAC population with less restrictive eligibility than recent registrational trials. Post-hoc analyses identify key clinical and molecular drivers of early death and confirm a consistent survival benefit with elraglusib/GnP. These hypothesis-generating findings directly inform eligibility criteria, stratification, and endpoint assumptions for the planned phase 3 trial. Clinical trial information: NCT03678883 .

653 Background: Elraglusib (9-ING-41), a novel small molecule inhibitor of GSK-3ß, has a multimodal mechanism of action that enhances chemotherapy cytotoxicity and regulates anti-tumor immune cell response. Elraglusib was evaluated in a randomized, open-label, phase 2 study (NCT03678883) comparing elraglusib/GnP vs GnP in previously untreated mPDAC. Methods: Pts were randomized 2:1 to GnP plus elraglusib 9.3 mg/kg IV once weekly or GnP. Primary endpoint was mOS, with 1-yr OS rate estimates summarizing clinical benefit throughout the study. Secondary endpoints were ORR, mPFS, and TEAEs/TRAEs. Pre-dose cytokines, mutational analysis, and immunophenotyping were correlated with outcomes. An oral presentation at ASCO 2025 discussed preliminary data. Results: As of 27 April 2025, the primary analysis set included 155 pts in the elraglusib/GnP arm and 78 pts in the GnP arm, with 52.8% males and 57.5% ECOG PS 1. The 1-yr OS rate was 44.1% with elraglusib/GnP vs 22.3% with GnP; the mOS was 10.1 mo with elraglusib/GnP vs 7.2 mo with GnP (HR, 0.62; p=0.01) with approximately 79% events recorded (25.8% of pts on elraglusib/GnP and 10.3% on GnP were censored with the majority at >12 mo OS). Improved OS with elraglusib/GnP was consistent across all randomized pts and subgroups regardless of liver metastases, ECOG status, or baseline CA 19-9 levels. Most common TRAE with elraglusib/GnP was grade 1-2 transient visual impairment (66.5% pts vs 0 with GnP). Most common grade ≥3 TEAEs with elraglusib/GnP (vs GnP) were neutropenia 52.3% (vs 30.8%) and anemia 25.2% (vs 29.5%). No differences in sepsis/febrile neutropenia rates were between arms. RAS , TP53 and CDKN2A co-mutations were associated with worse OS in the elraglusib/GnP arm only (p<0.05). Elevation in pre-dose cytokines including CXCL2 correlated with improved OS in the elraglusib/GnP arm. Additionally, increased CD8+ T cells, granzyme B, and NK cells and reduced MDSCs were observed in elraglusib-treated tumors. Conclusions: A significant benefit for 1-yr OS and mOS and a favorable trend for ORR were observed with the addition of elraglusib to GnP. The mOS was lower in the GnP arm vs historical studies, likely due to early deaths in the first 2 months, but aligns with mOS estimates in the real-world analysis with broad heterogeneous population. Our study included 19.7% pts with albumin <3.0 g/dL and >25% with CA 19.9 levels > 8,000 U/mL. Immune correlates support elraglusib’s immune-modulatory role. Final efficacy data cut-off in Dec 2025 and correlative studies will be presented. Clinical trial information: NCT03678883 . Outcome Elraglusib/GnPN=155 GnPN=78 Primary endpoint: mOS (mo)HR=0.62; log-rank p=0.01 10.1 7.2 Events, n (%) 115 (74.2) 70 (89.7) Primary endpoint: 1-yr OS (%) 44.1 22.3 18-month OS (%) 20.5 4.4 24-month OS (%) 13.2 0 mPFS (mo)HR=0.9; p=NS 5.6 5.1 Events, n (%) 136 (87.7) 75 (96.2) ORR, n (%) 44 (28.4) 17 (21.8)