831P Outcomes of immune checkpoint inhibitors in patients with metastatic uveal melanoma treated with tebentafusp

Metastatic uveal melanoma (MUM) is a nearly universal fatal disease with limited treatment options. Tebentafusp, novel bispecific immune mobilizing T cell receptor, provides an overall survival (OS) benefit for MUM in HLA-A*02:01 positive patients despite low response rate (ORR). Immune checkpoint inhibitors (ICI) first line therapy also have ORR but improved survival. Little known about the outcomes of who receive sequential ICI and tebentafusp. In this single center retrospective cohort study, we included treated tebentafusp (anti PD1 +/- anti CTLA-4) between 2016-2021. Investigator-assessed rates (RR), progression free (PFS) OS were analyzed compared when used before or after X2, Fisher’s exact Mann-Whitney U tests to compare groups Cox proportional hazards models fitted. The Log-rank test was assess PFS OS. Twenty identified: 10 received following (T-I) prior (I-T). Disease characteristics similar amongst both (Table). Response T-I group were: partial (PR): 10% (1), stable (SD): 30% (3) progressive (PD): 60% (6). For I-T corresponding SD: 20% (2) PD: 80% (8), p = 0.63 groups. Median from initiation 2.86 months (95%CI 2.37-NA) 2.35 (95% CI 0.92-NA) I-T, (p=0.046). start 21.47 15.78-NA) T-I, 16.88 8.52-NA) (p=0.38).Table: 831PCovariateICI - Teb (n=10)Teb (n=10)p-valueAge0.82Median60 (51 64)57 (50 66)Sex1Female4 (40)5 (50)Male6 (60)5 (50)IV Stage0.44M1a8 (80)5 (50)M1b1 (10)3 (30)M1c1 (10)2 (20)ECOG108 (80)7 (70)12 (20)3 (30)Extra Liver Mets1No3 (30)3 (30)Yes7 (70)7 (70)Increased LDH0.63No8 (80)6 (60)Yes2 (20)4 (40) Open table new tab small series, PD- 1 CTLA-4 blocking antibodies may show better clinical efficacy administered rather than before. A larger study needed confirm these data. Erica Koch Hein Diana Paola Arteaga Ceballos contributed equally study.