Tebentafusp (tebe) in a real-world cohort of 72 French metastatic uveal melanoma (UM) patients (pts)

e21583 Background: Up to 50% of UM pts will develop metastases with poor overall survival (OS) and limited treatment options. Tebe, a bispecific T-cell engager binding CD3 and the gp100 protein presented by the HLA A*02-01, recently showed a benefit in overall response rate (ORR), progression-free survival (PFS) and OS in HLA A*02-01 pos metastatic UM (mUM) pts in the IMCgp100-202 phase III trial. Prior to the EMA approval, French Health Authorities allowed an early access to tebe in May 2021 to UM metastatic pts. We here report our real-world experience with tebe in metastatic UM pts. Methods: Ongoing ambispective cohort of mUM pts treated with tebe in France. Metastases are evaluated according to RECIST 1.1 with assessments every 12 weeks (liver MRI +/- CT-scan). ORR, PFS, OS and toxicities are retrieved. Results: 72 pts started tebe between May 26 th 2021 and December 12 th 2022 (29 men and 43 women). Median age was 61 yo (32-78). Thirty, 34 and 7 patients underwent enucleation proton beam therapy or brachytherapy, respectively (one pt did not receive local treatment). The median time to first metastasis was 24 months (0-276). Tebe was prescribed in first-line in 46 patients, in second-line or more in 26 patients. Metastatic sites at tebe initiation were liver, lung, skin, bone and muscle in 71, 4, 2, 3 and 2 patients, respectively. Liver was the sole metastatic site in 63/72 patients (87.5%). With a median follow-up of 44 weeks, patients received a median of 36 weeks of tebe. Thirty patients discontinued tebe because of disease progression, two because of poor health status and none for toxicity. Of 60 assessable pts, 33 (55%) pts showed stable disease and 5 (8%) showed partial response as best response according to RECIST 1.1. Median PFS was 28 weeks (confidence interval 95% [CI95%]: 8-56) in the global cohort. OS at 12 months was 74% ([CI95%] = 0.62-0.89) in the global cohort, 73% ([CI95%] = 0.55-0.99) and 74% ([CI95%] = 0.57-0.97) in 1 st and 2 nd line and more, respectively. To date, 13 pts died. Circulating tumor DNA analyses and monitoring of peripheral blood leukocytes are ongoing and will be available by June 2023. Conclusions: In this ongoing, real-world, cohort of metastatic UM pts, tebe is associated with similar clinical outcomes as in the IMCgp100-202, phase III trial. Translational studies on blood and tumor samples are ongoing to identify predictive biomarkers of clinical benefit to this drug.