Purpose: The EORTC 18991 trial assessed the effect of long-term adjuvant pegylated interferon (Peg-IFN) alpha-2b administered weekly in patients with lymph node-positive melanoma. Serum concentrations were analyzed to determine exposure to Peg-IFN alpha-2b.
Methods: After surgery, patients were randomized to receive Peg-IFN alpha-2b or to observation only. The treatment group received 6 microg/kg/week Peg-IFN alpha-2b subcutaneously for 8 weeks, followed by a maintenance dose of 3 microg/kg/week for up to 5 years. Blood samples were collected between months 3 and 60.
Results: A total of 208 Peg-IFN alpha-2b concentrations from 48 patients were available. Serum trough concentrations increased in a dose-related manner. Mean dose-normalized serum concentrations and intersubject variability over the 5-year study period in patients with melanoma were similar to those observed in patients with chronic hepatitis.
Conclusion: Data suggest that the exposure to Peg-IFN alpha-2b was sustained during long-term adjuvant treatment with Peg-IFN alpha-2b in patients with melanoma, consistent with the EORTC 18991 trial's conclusion of a significant, sustained, and relapse-free survival benefit.