The impact of ImmunoPrecision in small bowel adenocarcinoma

e16333 Background: Although approaches to treating adenoCA of the small bowel (SBA) are extrapolated from those of the colon, SBA has distinct pathogenesis, clinical presentation and poorer prognosis. We examine the impact of SBA treatment by ImmunoPrecision, which combines Immunotherapy and Precision genomic targeting. Methods: SBA pts were identified retrospectively from Cedars-Sinai electronic health record (2000 – 2022) on an IRB-approved protocol. Microsatellite status and genomic testing were done in CLIA-certified, CAP-accredited labs. Pt characteristics, pathology, in-depth clinical history and genomics were summarized with descriptive statistics. Endpoint of median OS was estimated by Kaplan-Meier and calculated from pre-treatment imaging to last event. Treatment groups were compared using log-rank test. Results: Between Jan 2003 – Dec 2022, 137 stage 1 – 4 SBA pts (93 duodenal; 44 jejunal/ileal) were identified. Median age was 67 (range 22 – 95). Microsatellite status and genomic testing data were done or known for 72 pts (53%). In 35 pts who had metastases at initial presentation, 15 pts had NGS genomics, which identified actionable targets: 20% Her2 amp/mut , 13% FGFR1 amp/mut , 7% ALK fusion , 7% KRAS G12C, and 7% ATM R35*. 40% of 10 metastatic pts tested for microsatellite status were MSI/TMB-High, and only 1 pt received immunotherapy. In pts with metastases, median OS was 9.5 mo in duodenal adenoCA (51 pts) vs 13.0 mo in jejunal/ileum adenoCA (23 pts) (p = 0.46). There was a non-significant improvement in median OS to 20.5 mo in metastatic duodenal adenoCA pts who received targeted inhibition of actionable genomics or had MSI/TMB-High status (p = .51). Conclusions: Our real-world cohort of metastatic duodenal adenoCA shows a trend toward improved median OS from ImmunoPrecision targeting of frequent MSI/TMB-High status and actionable genomics. ImmunoPrecision clinical trial investigation is warranted in this rare SBA population. [Table: see text]