Double-blinded, randomized phase II study using embolization with or without granulocyte-macrophage...

To investigate the effects of immunoembolization with granulocyte-macrophage colony-stimulating factor (GM-CSF) in patients with uveal melanoma (UM) with liver-only metastasis.

In this double-blind phase II clinical trial, patients were randomized to undergo immunoembolization or bland embolization (BE). Lobar treatment was performed with GM-CSF or normal saline solution mixed with ethiodized oil followed by embolization with gelatin sponge emulsified with iodinated contrast medium. Fifty-two patients (immunoembolization, n = 25; BE, n = 27) were enrolled. Response was assessed after every two treatments. The primary endpoint was overall response rate (ORR) of liver metastases. Progression-free survival (PFS), overall survival (OS), and immunologic responses were secondary endpoints.

There were five partial responses in the immunoembolization group (ORR, 21.2%; 90% confidence interval [CI], 10.3%-30.5%) and three in the BE group (ORR, 16.7%; 90% CI, 6.3%-26.9%). Stable disease was seen in 12 patients in the immunoembolization group and 19 in the BE group. OS times were 21.5 months (95% CI, 18.5-24.8 mo) with immunoembolization and 17.2 months (95% CI, 11.9-22.4 mo) with BE. The degree of proinflammatory cytokine production was more robust after immunoembolization and correlated with time to "systemic" extrahepatic progression. In the immunoembolization group, interleukin (IL)-6 levels at 1 hour (P = .001) and IL-8 levels at 18 hours after the procedure (P < .001) were significant predictors of longer systemic PFS. Moreover, a dose-response pattern was evident between posttreatment serum cytokine concentrations and systemic PFS.

Immunoembolization induced more robust inflammatory responses, which correlated with the delayed progression of extrahepatic systemic metastases.