Phenotypic and Functional Analysis of Dendritic Cells and Clinical Outcome in Patients With High-Risk Melanoma Treated With Adjuvant Granulocyte Macrophage Colony-Stimulating Factor

Purpose Granulocyte macrophage colony-stimulating factor (GM-CSF) can induce differentiation of dendritic cells (DCs) in preclinical models. We hypothesized that GM-CSF–stimulated DC differentiation may result in clinical benefit in patients with high-risk melanoma. Patients and Methods We conducted a prospective trial in patients with high-risk (stage III B/C, IV), resected melanoma, with GM-CSF 125 μg/m2/d administered for 14 days every 28 days. Patients underwent clinical restaging every four cycles, with DC analysis performed at baseline and at 2, 4, 8, and 12 weeks. Results Of 42 patients enrolled, 39 were assessable for clinical outcome and DC analysis. Median overall survival was 65 months (95% CI, 43 to 67 months) and recurrence-free survival was 5.6 months (95% CI, 3 to 11 months). GM-CSF treatment caused an increase in mature DCs, first identified after 2 weeks of treatment, normalizing by 4 weeks. Patients with decreased DCs at baseline had significant increases in DC number and function compar...