Citations

Abstract Nearly 300,000 cancer patients are treated with fluoropyrimidine chemotherapy in the U.S. annually. Approximately one-third of patients experience severe and life-threatening toxicities, which can result in death. Deleterious genetic variants in DPYD, which encodes the rate-limiting enzyme of fluoropyrimidine catabolism (dihydropyrimidine dehydrogenase, DPD), have been correlated with severe toxicity in clinical studies. However, these variants explain only 10-30% of toxicity cases. Phenotypic measures of DPD function are attractive biomarkers of fluoropyrimidine toxicity risk with the potential to identify unknown causes of DPD deficiency. In this study, we compared two measures of DPD enzyme activity, blood plasma dihydrouracil to uracil ratio (UH2:U) and direct measurement of DPD activity in peripheral blood mononuclear cells (PBMCs) using 204 subjects with comprehensive DPYD genotype data. DPD PBMC measurements showed higher overall inter-individual variation compared to UH2:U ratios. Low correlation between UH2:U and PBMC measurements were noted for matched samples taken from the same subject. As expected, DPD metabolites (U and UH2) correlated with UH2:U ratio; however, no correlation was noted between U or UH2 levels and the PBMC DPD activity. Furthermore, when data were analyzed by genotype, no correlations were noted between UH2:U and PBMC DPD activity. We observed the expected decrease in UH2:U ratio for carriers of the four clinically tested DPYD variants and identified two novel variants associated with a significantly decreased UH2:U ratio. To further investigate the impact of rare genotypes and previously identified DPYD haplotypes on the UH2:U ratio, additional cohorts of 1994 and 500 subjects, enriched for specific genotypes, were utilized. Our results suggest that phenotyping may have limited validity as a single test when predicting DPD deficiency at an individual level and call into question the often-reported belief that PBMC DPD activity represents the "gold standard" for identifying DPD deficiency. Additional studies are needed to investigate correlations between phenotypic measures and 5-FU toxicity in patients, potentially as secondary biomarkers in conjunction with genetic tests. Citation Format: Brianna Bembenek, Kelly Bouchonville, Carlo Largiadèr, Steven M. Offer. Comparative analysis of phenotypic markers of DPD activity as biomarkers of 5-FU toxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3135.

Abstract Dihydropyrimidine dehydrogenase (DPD, encoded by the DPYD gene) is the rate-limiting enzyme in the catabolism of the widely used chemotherapeutic drug 5-fluorouracil (5-FU). Genetic variations in DPYD are predictive biomarkers of 5-FU toxicity. One such biomarker, rs75017182 (the causal allele linked to the “HapB3” haplotype), has been suggested to promote alternative splicing of DPYD, leading to expression of an inactive proteoform. However, carriers of rs75017182 exhibit only moderately increased risk of 5-FU toxicity and modestly decreased ex vivo DPD activity compared to carriers of another well-studied splice variant, rs3918290 (*2A). We hypothesized that, unlike *2A, the rs75017182 variant does not cause obligate alternative splicing but instead promotes partial alternative splicing. To test this, we generated dual-fluorescent minigene reporter constructs containing either the G (wildtype) or C (variant) allele. In our minigene system, alternative splicing was elevated in cells transfected with C-containing vectors via flow cytometry, though levels were lower than those observed in a parallel *2A model. To investigate contributions of other variants in LD with rs75017182, we expanded the reporter to include additional relevant genomic regions. The analyses were complemented by the study of in vivo splicing in cells engineered to harbor various combinations of variants and in lymphoblastoid lines carrying specific genotype combinations. Overall, our findings demonstrate that rs75017182-C promotes only partial alternative splicing, eliciting a modest decrease in DPD activity and explaining its comparatively weak association with severe 5-FU toxicity. Additional variants in LD have a minimal impact on splicing and 5-FU sensitivity. Citation Format: Lauryn Allyn Hahn, Ryan Schwartz, Hannah Marie Krause, Lulu Jiang, Brianna Bembenek, Kelly Bouchonville, Steven M. Offer. Partial alternative splicing in carriers of DPYD rs75017182 explains modest association with severe 5-FU toxicity to 5-FU [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3137.

Abstract Background and Aims: Colorectal cancer is a leading cause of cancer mortality and most rectal cancers are mismatch repair proficient (pMMR), making them largely resistant to PD-1 inhibitors (PD1i). While PD1i achieves excellent complete response rates in MMR-deficient tumors, these represent <5% of rectal cancers. For the remaining 95% of patients, effective immunotherapy strategies are urgently needed. We evaluated two high-LET radiation approaches to prime pMMR rectal cancers to PD1i and enhance local control: 1) Diffusing alpha emitter Radiation Therapy (DaRT) implants, and 2) LET-optimized (Bragg Peak) protons + ATM inhibitor. An ATM inhibitor was evaluated with protons to evaluate whether it could produce a more alpha/carbon-like effect given the lower comparative LETd achievable in clinical treatment plans. Methods: In vitro proton irradiation of HCT116, HT29, SW480, and CT26 was performed as previously with dose averaged LET (LETd) values of 2.2 keV/um for ENT and 7.0 keV/um for BP protons. Female Balb/C mice were subcutaneously inoculated with 1×10^6 CT26 cells on one flank and 1×10^5 cells on the contralateral flank to establish primary and secondary (abscopal) tumors, respectively. PD1i monoclonal antibody (RMP1-14 Bio X Cell) was administered i.p. 100ug every 72 hours for 4 total doses. The ATM inhibitor AZD1390 was delivered via oral gavage at 20 mg/kg, PO 1 hour prior to radiation. For in vivo studies, radiation was delivered using a PXI SmART small animal irradiator with opposing lateral beams (225 kVp, 20 mA, 0.3mm Cu filter). Proton irradiation plans were produced as previously described. We used mass cytometry by time of flight (CyTOF) using the TME CD45 lymphocyte subpopulations based on multiple cell markers. Result: In our preliminary data we demonstrate that both DaRT and BP protons+ATMi synergize with PD1i to dramatically increase complete response rates at both primary and abscopal tumors by increasing DNA damage, activating innate immune pathways, and reducing immunosuppression within the tumor microenvironment. Critically, this effect was observed in a pMMR model which did not respond to PD1i or conventional X-rays+PD1i, highlighting the innovation and potential impact of this work. Conclusion: DaRT and BP protons ATMi prime pMMR colorectal cancer to PD1i, and all elements are clinically translatable. Citation Format: Cameron M. Callaghan. Particle therapy, ATM and PD-1 inhibition for pMMR rectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 2569.

Abstract Background: Diffuse pleural mesothelioma (DPM) is a highly aggressive malignancy with limited treatment options and poor prognosis. Although immune checkpoint inhibitors have improved outcomes, particularly for non-epithelioid subtypes, there remains no approved targeted therapy for mesothelioma. EGFR and MET are receptor tyrosine kinases frequently overexpressed in DPM, suggesting susceptibility to targeted antibody therapy. Amivantamab is a bispecific EGFR/MET antibody, originally developed for EGFR-mutant lung cancer, that blocks growth signals and engaging immune mechanisms. Given the high levels of EGFR and MET expression in mesothelioma, we evaluated the therapeutic potential of amivantamab in preclinical models. Methods: EGFR and MET transcript levels in DPM were analyzed using TCGA. Eight human mesothelioma cell lines were assessed by Western blotting and flow cytometry. Amivantamab binding, internalization, and signaling inhibition were examined using flow cytometry, confocal microscopy, and ligand-stimulated phosphorylation assays. Cytotoxicity and immune-effector activity were quantified using PBMCs, NK cells, and monocytes from healthy donors, along with an ADCC reporter assay. In vivo efficacy was tested in a DPM patient-derived xenograft (PDX) model in NOD/SCID-γ (NSG) mice supplemented with human NK cells and treated with amivantamab or control IgG. Results: TCGA analysis showed frequent EGFR/MET co-expression in DPM. Mesothelioma cell lines expressed higher EGFR and MET levels compared with mesothelial cells. Amivantamab strongly bound both receptors, induced receptor internalization, and inhibited EGF- and HGF-stimulated phosphorylation of EGFR, MET, and downstream AKT/ERK signaling. Direct cytotoxicity was minimal; however, the addition of PBMCs or NK cells resulted in robust, dose-dependent tumor cell killing consistent with antibody-dependent cellular cytotoxicity (ADCC). Reporter assays demonstrated 7-11-fold Fcγ receptor activation in tumor cells compared with ∼2-fold activation in non-malignant mesothelial cells. Co-culture with monocytes revealed amivantamab-induced trogocytosis, evidenced by loss of EGFR and MET from tumor-cell membranes. In the DPM PDX model, amivantamab produced 89.1% tumor-growth inhibition (TGI) relative to controls (P < 0.0001), with no overt toxicity observed in treated mice. Conclusions: Dual EGFR/MET targeting with amivantamab produced potent antitumor effects in mesothelioma through coordinated receptor-signaling blockade, ADCC, and monocyte-mediated trogocytosis. These results support amivantamab as a promising targeted therapeutic strategy for EGFR/MET-positive DPM, particularly epithelioid subtypes that currently derive limited benefit from immunotherapy. Citation Format: Shinichiro Suzuki, Kaushal Parikh, Ezequiel Tolosa, Kuan-Li Wu, Jennifer Ayers-Ringler, Lin Yang, Katherine E. Smith, Farhad Kosari, Aaron S. Mansfield, . Enhancing antibody-dependent cellular cytotoxicityin mesothelioma through concurrent EGFR and MET targeting withamivantamab [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5547.

Abstract Background: Most colorectal cancer (CRC) arises from polyps and is mainly prevented by polypectomy. The most important polyps to manage with colonoscopy are those with highest CRC risk- namely, advanced polyps (> 1cm, villous histology or high-grade dysplasia (HGD). Yet, 48% of advanced polyps recur within 1 to 3 years of removal, and up to 5% of advanced polyps under surveillance still progress to CRC. We performed this pilot study to investigate molecular and microenvironment heterogeneities of polyps and how they might impact their clinical behavior. Methods: GeoMx spatial transcriptomics was performed on FFPE tissues from three different polyp outcome phenotypes (POPs) including the polyp that does not recur (POP-NR), that recurs following polypectomy but cured by colonoscopy (POP-R) or the polyp despite polypectomy develops CRC at the polypectomy(ies) site (POP-CRC). Normal colon and polyp with low or HGD from the index polyp were assessed from 6 patients with POP-NR, 9 with POP-R and 12 with POP-CRC with a minimum of 2 follow up colonoscopies at 3-year intervals. Epithelium was identified as PanCK positive, and stroma identified as PanCK negative and positive nuclear staining. Cell type deconvolution was implemented using single-cell adult human intestinal tract catalogue (Elmentaite et al., https://www.gutcellatlas.org/). Differential gene expression (DEG), cell type abundance and functional enrichment analyses was performed using linear mixed effects model, and observations with p-value < 0.05 and log2FC >= |1| are reported. Results: The greatest number of DEGs were identified in stroma of the index POP-CRC compared to POP-NR polyps (n = 17 down and 11 upregulated genes), followed by epithelium of the index POP-CRC vs POP-NR polyps (n = 10 down and one upregulated gene(s)). Between the index POP-CRC and POP-R, epithelium showed downregulation of 7 genes, and upregulation of no genes. In stroma two genes were down and none upregulated. Four genes were downregulated in stroma of the index POP-R vs POP-NR polyp and 3 in epithelium, and one gene was upregulated in stroma and another in epithelium. MZT2B was upregulated in stroma of both the index POP-R (log2FC = 1.09, p-value = 0.0014) and POP-CRC (log2FC = 1.29, p-value = 0.0001) and has been implicated as a prognostic marker associated with worse prognosis in certain cancers. IgM and IgA plasma cells, proximal progenitors, MMP9+ inflammatory macrophages and myofibroblasts were found to be downregulated in epithelium of index POP-CRC and POP-R compared to POP-NR polyps; while microfold cells were downregulated in stroma of index POP-CRC and POP-R compared to POP-NR polyps. Conclusions: The stromal microenvironment and less so, epithelial features present in the index polyp differ based on a polyp’s future clinical behavior. The polyp-immune interaction warrants further study as a potential prevention target against polyp progression. Citation Format: Mrunal Dehankar, Lisa A. Boardman, Daniel O'Brien, E. Aubrey Thompson, Jennifer M. Kachergus, Ji Shi, Alexej Abyzov, Milovan Suvakov, Rondell P. Graham, Chen Wang. Stromal immune composition significantly contributes to adenomatous polyp recurrence or progression to cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 4018.

The temporomandibular joint (TMJ) is an anatomically rich area, and TMJ surgery may be considered both anatomically and technically challenging, particularly when the pathology is complex or poorly visualized on conventional imaging. This case series highlights the role of advanced in-house 3D printing in TMJ surgical planning. The authors present 7 diverse TMJ surgical cases treated over the past decade, where 3D models were instrumental in preoperative planning. Models were fabricated from CT and/or MRI data using different materials for the print and model design, and customized to highlight relevant anatomy or pathology. This case series featured patients with a range of different TMJ conditions, such as condylar resorption, benign tumors, and joint ankylosis. 3D models improved the visualization of pathologic anatomy, enabled surgical simulation, and guided prosthesis design or resection planning. Models facilitated interdisciplinary collaboration and enhanced patient safety by improving anatomic orientation near critical structures. Outcomes included restored mandibular function, successful removal of the pathology, and improved facial symmetry, with follow-up ranging from 1 to 3 years. Advancing technology and capability in 3D printing can be very helpful in identifying the extent of disease, anatomic boundaries, critical regional anatomic risk, predicted joint mechanics, and patient education. Depending on the type of disease, different types of modeling and printing techniques may be warranted to best illustrate to the surgeon and patient how to proceed with treatment.

Objective: To assess the feasibility and clinical impact of sideline telemedicine for real-time injury assessment during high school athletic events in rural communities and to determine its potential effect on emergency department (ED) utilization. Design: Prospective, observational cohort study. Setting: Three rural high schools in southeast Minnesota without on-site athletic trainer or emergency medical services coverage. Participants: High school athletes and attendees injured during school-sponsored athletic events during the 2021 to 2022 school year. Intervention: Sideline telemedicine consults were initiated by school officials using tablets to connect with on-call dual board-certified emergency and sports medicine physicians. Consults included video-based assessment, triage, return-to-play guidance, and follow-up recommendations. Main Outcome Measures: Disposition after consultation (return to play, outpatient follow-up, ED referral), satisfaction scores using the 10-item Telehealth Satisfaction Scale, and patient-reported intent to seek ED care if telemedicine were unavailable. Results: Telemedicine was activated 15 times. Most (53%) injuries were musculoskeletal. Two (13%) patients were referred to the ED, where time-sensitive diagnoses (NSTEMI, testicular torsion) were confirmed. Thirteen patients were treated without ED referral; 6 (46%) reported they would have otherwise visited the ED. All diagnoses were confirmed by outpatient follow-up. Telehealth Satisfaction Scale scores were high: interpersonal communication (mean 4.00), respectfulness (3.96), and technical quality (3.99). Conclusions: Sideline telemedicine is a feasible and well-received model for acute injury evaluation at rural athletic events lacking on-site medical providers. It may reduce unnecessary ED use while preserving care quality and satisfaction, offering scalable support for resource-limited sports settings.

Abstract Background: High-dose interleukin-2 (IL-2) is administered after tumor-infiltrating lymphocyte (TIL) infusion to promote in-vivo expansion and persistence, yet optimal dosing and the clinical significance of out-of-specification (OOS) TIL products remain unclear. We investigated the impact of number of infused IL-2 doses and manufacturing OOS status on outcomes in metastatic melanoma treated with commercial TIL therapy. Methods: We retrospectively analyzed 31 patients treated across three Mayo Clinic sites. Planned IL-2 was 600,000 IU/kg every 12 hours for ≤6 doses; actual dosing varied based on clinical tolerance. Patients were grouped as low (0-2) vs high (≥3) IL-2 doses. TIL products were classified as within-specification or OOS per commercial release criteria. Survival associations were evaluated using Kaplan-Meier and multivariable Cox regression. Results: In our 31-patient cohort, the median age was 59 years (range 17-77), 58% were male, and 84% had ECOG 0. At TIL infusion, M-stage distribution was M1a 6%, M1b 10%, M1c 61%, and M1d 23%. LDH was elevated above the upper limit of normal in 42%. The median number of IL-2 infusions was 4 (range 0-6); 58% of patients received ≥3 doses, while 2 patients (6%) received none. Out-of-specification (OOS) TIL products occurred in 6 patients (19%). Best responses included complete response (26%) and partial response (23%), for an overall response rate of 48% and a disease-control rate of 61% (CR + PR + SD). Among responders, the median duration of response was 84 days (95% CI 73-95). At data cutoff, the median follow-up was 253 days (95% CI 137-370). The most common grade 3/4 toxicities occurring >14 days after TIL infusion were lymphopenia (39%), anemia (16%), and thrombocytopenia (10%). Median progression-free survival (PFS) was 99 days (95% CI 73-125) with 20 progression events, and median overall survival (OS) was 193 days (95% CI 32-354) with 13 deaths. Number of infused IL-2 doses was dependent on patients tolerability. Receiving ≥3 IL-2 doses was associated with improved overall survival (394 vs 101 days; p < 0.001) and a trend toward longer progression-free survival (110 vs 59 days; p = 0.055). OOS products predicted inferior PFS (30 vs 110 days; p = 0.003) and showed a trend toward worse OS (120 vs 394 days; p = 0.079). In multivariate analysis, ≥3 IL-2 doses independently improved PFS (HR 0.20, 95% CI 0.06-0.69; p = 0.011) and OS (HR 0.09, 0.02-0.36; p = 0.001), while OOS status increased risk of progression (HR 8.10, 2.24-29.25; p = 0.001) and death (HR 6.16, 1.35-28.20; p = 0.019). Conclusions: Higher number of infused doses IL-2 and meeting commercial TIL release criteria were independently associated with improved outcomes. Citation Format: Mohamed A. Aboelatta, Jeffrey E. Johnson, Jabra G. Zarka, Matyáš Benada, James W. Jakub, Roxana S. Dronca, Ruqin Chen, Mahesh Seetharam, Deepti Behl, Svetomir N. Markovic, Lisa A. Kottschade, Heather N. Montane, Matthew S. Block, Anastasios Dimou, Robert R. McWilliams, Paula Gill, Yi Lin, Arkadiusz Z. Dudek. Impact of number of IL-2 infusions and product out of specification status on outcomes of tumor infiltrating lymphocyte therapy for melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3706.

Abstract Multiple Myeloma is the second most common hematologic malignancy among US adults and remains incurable. Immunotherapies, including bispecific T cell engagers (BiTEs) targeting BCMA, have greatly improved outcomes. However, a significant fraction of patients still fail to respond, or develop resistant disease. Conventional models of T cell cytotoxicity focus on delivery of perforin- and granzyme-containing granules following antigen recognition and T cell activation, an inefficient mode of killing that requires effector-to-target cell contact. Activated T cells, however, also secrete cytokines capable of diffusing and acting on distant targets. This raises the possibility of paracrine killing, in which these cytokines induce tumor cell death independently of cell-cell contact.Tumor necrosis factor (TNF) is a key cytokine released during T cell activation and is unique in that it can drive either cell survival or cell death. Although most cells default to cell survival and NFkB-mediated inflammation, several modulators can shift this survival signaling toward cell death. We therefore hypothesized that sensitizing Myeloma cells to TNF could enable T cell paracrine killing and enhance the efficacy of anti-Myeloma T cell immunotherapies.To test this, we first established an in vitro model of clinical response to Teclistamab, a BCMA-directed BiTE, using Multiple Myeloma cell lines that displayed sensitive, intermediate, or resistant responses to T cell killing. Combining these data with assays of cytokine sensitivity and receptor expression, we found that susceptibility to TNF-mediated cell death was a major determinant of Teclistamab sensitivity. This correlation was further supported by reduction or complete abrogation of Teclistamab T cell killing of sensitive Myeloma cell lines when soluble TNF was neutralized from these co-cultures using monoclonal antibodies. Pharmacologic inhibition and CRISPR-mediated deletion of known regulators of TNF survival-signaling further sensitized Myeloma cells to both TNF and T cell killing. In the absence of these regulators, BCMA-negative myeloma targets retained sensitivity to Teclistamab, supporting the idea that the main mechanism of cell death was indeed paracrine killing.Together, these findings establish a direct link between TNF sensitivity and T cell-mediated killing of Myeloma cells, and support TNF-driven paracrine killing as a dominant mechanism of response to Teclistamab. Enhancing this TNF-mediated death signaling may therefore represent a strategy to overcome resistance and improve clinical efficacy of T cell-based immunotherapies in Multiple Myeloma. Citation Format: Allison Carr, Elise Sintim-Aboagye, Adrian Ting, . TNF-driven paracrine killing determines the cytotoxic efficacy of Teclistamab in Myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1636.

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) is driven predominantly by oncogenic KRAS signaling and characterized by an immunosuppressive, fibrotic tumor microenvironment that limits therapeutic responses. RMC-6236, a pan-KRAS inhibitor, and ONIOYID, an investigational anti-tumor agent, each demonstrate partial activity in KRAS-mutant cancers. However, their combined therapeutic potential in PDAC remains unexplored. Here, we evaluated the anti-tumor efficacy, survival benefit, and immunomodulatory effects of RMC-6236, ONIOYID and irinotecan alone and dual combinations multiple in vitro and in vivo PDAC models. Methods: In vitro cytotoxicity assays were performed using KPC, PANC-1, AsPC-1, and PANC-02 cell lines. In vivo therapeutic studies were conducted in orthotopic KPC and PANC-1 tumor models. RMC-6236 was administered orally at 10 mg/kg; ONIOYID and irinotecan was administered intravenously at 5 mg/kg. Tumor growth inhibition, survival, collagen deposition, and immune cell infiltration were analyzed. Tumor microenvironment remodeling was quantified via immunohistochemistry for CD8, CD4, collagen I, and fibronectin. Results: The combination of RMC-6236 and ONIOYID elicited potent anti-tumor effects across all evaluated PDAC cell lines, achieving greater than 90% growth inhibition in vitro. In vivo, co-treatment resulted in more than 90% tumor regression in both KPC and PANC-1 xenograft models, markedly surpassing the efficacy of individual monotherapies and other dual-agent controls. Combination therapy significantly extended overall survival and produced sustained suppression of tumor progression. Mechanistic analyses revealed a substantial reduction in collagen and fibronectin deposition within the tumor microenvironment, consistent with attenuation of desmoplasia. Immune profiling demonstrated a robust enhancement of intratumoral CD8+ and CD4+ T-cell infiltration, along with a pronounced decrease in survivin expression. Importantly, no observable systemic toxicity was detected in treated animals. Conclusions: RMC-6236 combined with ONIOYID yields synergistic anti-tumor effects, remodels the fibrotic PDAC microenvironment, enhances T-cell infiltration, and significantly improves survival in aggressive pancreatic tumor models. These findings provide strong rationale for clinical evaluation of RMC-6236-based combination therapies for KRAS driven PDAC. Citation Format: Hari Krishnareddy Rachamala, Fang Wei, Debabrata Mukhopadhyay, Hani M. Babiker. Combined KRAS pathway inhibition and ONIOYID treatment enhances tumor regression, attenuates desmoplasia, and augments T cell infiltration in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5842.