A pilot study of sunitinib malate in patients with metastatic uveal melanoma

The prognosis of patients with metastatic uveal melanoma is poor and there are limited therapeutic options. C-kit is expressed in the majority of patients with metastatic uveal melanoma. In this pilot trial, we examined the toxicity and efficacy of sunitinib malate, a multitarget tyrosine kinase inhibitor, in patients with metastatic uveal melanoma. Twenty patients with metastatic uveal melanoma expressing c-kit, 17 of whom failed previous treatments, were included in this study. Patients received sunitinib malate 37.5 mg daily continuously in 4-week cycles. The evaluation of response was carried out every 8 weeks. The overall survival (OS) and progression-free survival (PFS) were evaluated using Kaplan-Meier survival curves and differences in survivals were tested using the log-rank test. There was one partial response and 12 stable disease (SD) after sunitinib treatment. The median OS and PFS were 8.2 and 4.2 months, respectively. Three patients had SD for more than 12 months with sunitinib after failing previous treatments. The most common adverse events were fatigue (90%), diarrhea (60%), hemorrhage (55%), anorexia (45%), hand-foot syndrome (25%), hypothyroidism (25%), and rash (25%). Eleven patients required a dose reduction to 25 mg daily secondary to grade 3 adverse events. The degree of c-kit expression in melanoma cells was not associated with longer PFS or OS. Patients who developed systemic metastases after more than 5 years of their initial diagnosis had better PFS (median PFS: 5.8 vs. 2.6 months, P=0.005). Sunitinib was safely administered and showed potential clinical benefit in patients with metastatic uveal melanoma. The lack of a correlation between c-kit expression and clinical outcomes requires further investigation on the mechanism of sunitinib in metastatic uveal melanoma.