Real-world impact of immunotherapy in metastatic uveal melanoma: A retrospective single-center study.

e21594 Background: There is no standard treatment for mUM and the efficacy and safety of IT and comparison with chemotherapy in real-world practice has not been well defined. Methods: We conducted a single-center retrospective observational study approved by the Institutional Review Board (IRB) at the N.N. Blokhin National Medical Research Center of Oncology, focusing on the treatment of patients with metastatic uveal melanoma (mUM) from 2000 to 2023. Our primary objectives were to evaluate clinical outcomes in real-world settings between patients who received chemotherapy (ChT) prior to 2017 and those who received immunotherapy (IT) after 2017. No formal balancing methods were applied, the group analyzed based on the treatment periods and available clinical data. Results: A total of 347 pts with mUM were included. The mean age was 54 years (range: 20-76). 56 pts were lost to follow-up, and 23 declined the proposed treatment. 124 pts were included in the ChT group, and 144 in the IT group. In the ChT, the most commonly prescribed regimens were cyclophosphamide+vincristine+dacarbazine (n = 39, 41.5%) and paclitaxel+carboplatin (n = 18, 19.1%). In the IT - anti-PD-1 (n = 78, 54.2%), ipilimumab+nivolumab (n = 48, 33.3%), ipilimumab (n = 10, 6.9%), and tebentafusp (n = 8, 5.6%)*. Only 4 pts (3.2%) in the ChT received 3 lines of therapy, while in the IT, 63.9% (92) received 3 or more lines of therapy, with 2 of them receiving 6 lines. The results are reported in Table 1. Furthermore, we observed that in the IT group, 26 patients received additional local treatment methods (STRT/Isolated hepatic perfusion/TACE) alongside immunotherapy, resulting in a median PFS of 3.4 months (95% CI: 3.1–4.1) compared to 9.1 months (95% CI: 6.8–14.2) with IT alone (HR: 0.46, 95% CI: 0.30–0.71, p < 0.001), a 36-month OS of 20% versus 59%, and a median OS of 47 months (95% CI: 21.7–51.8) compared to 18.6 months (95% CI: 16.5–26.0) (HR: 0.46, 95% CI: 0.24–0.88, p = 0.02). Gr 3-4 treatment-related AEs in the ChT were observed in 28.2% vs 30.6% in the IT. Conclusions: Despite the low frequency of objective response, the administration of IT significantly increases the survival of patients with mUM. The addition of local treatment methods to IT in cases of isolated liver involvement could be considered as a viable approach. Results. ChT IT all HR The median time to metastasis from the primary tumor 3.02 yrs 2.10 yrs Median PFS 1.8 mon. (95% CI 1.4-2.1) 4.07 mon. (95% CI 3.4-5.3) 0.36, 95% CI 0.28-0.47, p<0.0001) ORR 0% 11.8% (4-CR, 13-PR) Disease control rate (DCR) 25% 36.8% Median OS since initiation of first-line therapy 5.6 mon (95% CI 4.2-6.83) with a median follow-up of 5.69 mon 21.7 mon (95% CI 17.63-27.17) with a median follow-up of 17.27 mon 0.21, 95% CI 0.16-0.29, p<0.005). 24 mon-OS 7% 48% 36 mon-OS 0% 29%