Long-term overall survival after isolated liver perfusion with melphalan in patients with isolated liver metastases of uveal melanoma (SCANDIUM trial).

9532 Background: Uveal melanoma is a rare subtype of melanoma characterized by frequent metastases to the liver. The median survival for patients with liver metastases is less than one year, and there are few systemic treatment options available, providing only small survival benefits. Patients with liver metastases of uveal melanoma were in the SCANDIUM trial randomized to a one-time treatment with isolated hepatic perfusion (IHP) with high dose melphalan and investigator´s choice. We have previously reported that IHP gave significantly superior response rates and progression-free survival compared to best alternative care Furthermore, the primary endpoint, overall survival (OS) rate at 24 months was numerically higher for the IHP treated group (46.5% vs 29.5%), but the difference was not statistically significant. Here we present extended OS follow-up. Methods: In this randomized, controlled, phase III trial, treatment naïve Swedish patients with isolated liver metastases from uveal melanoma were between 2013 and 2021 randomly assigned in a 1:1 ratio to receive a one-time treatment with IHP or best alternative care (control group). No crossover from the control group to the IHP group was allowed. Results: A total of 87 patients were randomized and assigned to either IHP (43 patients) or control (44 patients). In the IHP group, 41 (89%) patients received IHP. In the control group, the first-line treatment was chemotherapy (49%), immunotherapy (39%) or localized treatment interventions (9%). The overall response rate was 40% in the IHP group, with a median duration of response of 13.7 months (95% CI, 11.6-18.3, n=17). At a minimum follow-up of 36 months, the 3-year OS rate was 18.6% (95% CI, 10.0-34.8%) in the IHP group compared to 9.1% (95% CI, 3.6-23.1%) in the control group (p=0.23, fisher exact test), and the 5-year OS rate was 16.3% (95% CI, 8.3-32.1%) compared to 6.8% (95% CI, 2.3-20.3%). The median OS in the IHP group was 21.4 months (95% CI, 19.0-30.4 months) compared to 17.3 months (95% CI, 13.8-22.3 months) in the control group (p=0.11, log-rank test). Conclusions: This extended analysis from the SCANDIUM trial supports long-term efficacy of a one-time treatment with IHP compared to best alternative care in patients with isolated liver metastases of uveal melanoma. Clinical trial information: NCT01785316 .