Characterization of the real-world first line (1L) use of single dose tremelimumab regular interval durvalumab (STRIDE), for treatment of unresectable hepatocellular carcinoma (uHCC), using two electronic medical record (EMR) databases.

534 Background: In October 2022, the US FDA approved the STRIDE (Single Dose Tremelimumab Regular Interval Durvalumab) regimen, comprising tremelimumab 300 mg for 1 dose plus durvalumab 1500 mg every 4 weeks, for the 1L treatment of uHCC in adults aged ≥18 years. Thus far there is limited data characterizing STRIDE's 1L use in the real world. This observational study aims to describe patient characteristics, and clinical profiles of a 1L STRIDE cohort. Methods: A retrospective cohort study was conducted using EMR data from two community oncology practice networks, Florida Cancer Specialists and American Oncology Network, from January 1, 2018, to March 31, 2024. Adults with HCC who received ≥1 administration of the STRIDE regimen as 1L treatment following diagnosis were included. Patients with evidence of other cancers or systemic therapies pre-index date were excluded, to establish a cancer-naïve cohort at index. Index date was first administration of STRIDE. The analysis described the patient characteristics and clinical profile at index date. Patient demographics, severity indicators (cancer stage, albumin-bilirubin index (ALBI), alpha fetoprotein (AFP), Eastern Cooperative Oncology Group (ECOG)) and lab data were assessed on or closest to index date. Results: 79 patients initiated the 1L STRIDE regimen. The median (P25, P75) age at index was 70 (63.2-76.4) years. 72.2% were males, 64.6% were white, and 69.6% were overweight or obese patients. 95% had their first HCC diagnosis between 2022-2024 and the mean time from diagnosis to index date was 3.8 months (SD: 10.2). Among patients with reported cancer stage (n=57), most (82.5%, n=47) were diagnosed with stages IIIA to IVB. 18% had ECOG scores ≥2. 86% had ALBI grades between 2-3; 42.1% had AFP level ≥400 ng/ml; 30.4% had cirrhosis (among those that reported comorbidities) and 24.1% received any loco-regional therapy. Conclusions: Our study provides a real-world profile of patients on 1L STRIDE. Compared to the HIMALAYA trial, these findings suggest that patients in this real-world study tend to be older, diagnosed at late-stage, have a poor liver profile, and potentially worse prognosis over time. Further research is required to explore treatment pathways after index date, over a long follow-up, which may provide more insight into the continuity and effectiveness of IL STRIDE in the real-world.