Salvage-Targeted Kidney Cancer Therapy in Patients Progressing on High-Dose Interleukin-2 Immunotherapy The UCLA Experience

Purpose: To analyze the outcomes of patients with metastatic renal cell carcinoma treated with salvage-targeted therapy after progressing on high-dose interleukin (IL)-2 immunotherapy in a tertiary referral center. Materials and Methods: A retrospective nonrandomized cohort consisting of 286 patients with metastatic renal cell carcinoma treated from 2003 to 2010 was analyzed from the University of California, Los Angeles (UCLA) Kidney Cancer database. All patients underwent cytoreductive nephrectomy, and 21 patients received salvage-targeted therapy after progression on high-dose IL-2, whereas 111 patients received targeted therapy alone. The remaining 154 patients had other treatment combinations or experimental targeted therapy agents only. Since 2003, selection of patients for high-dose IL-2 was increasingly based on clinical, pathologic, and molecular criteria (UCLA CPM criteria). Disease-specific survival was calculated from diagnosis of metastatic renal cell carcinoma. Results: Patients selected according to UCLA CPM criteria and treated with salvage-targeted therapy after progressing on high-dose IL-2 experienced a significantly greater disease-specific survival (median not reached) than those treated with targeted therapy alone (30 months; P = 0.004). Since 2006, all high-dose IL-2 patients met the UCLA CPM criteria and were able to receive salvage-targeted therapy upon progression. Disease-specific survival calculated from initiation of targeted therapy was comparable for patients treated with salvage-targeted therapy after progression on high-dose IL-2 (34 months) versus first-line targeted therapy (26 months; P = 0.175). Discussion: Patients selected for high-dose IL-2 based on UCLA CPM criteria and treated with salvage-targeted therapy upon progression have achieved outstanding disease-specific survival. Our data suggest a new algorithm for carefully selected patients with metastatic renal cell carcinoma based on UCLA CPM criteria to receive first-line high-dose IL-2 while reserving their option for salvage-targeted therapy with uncompromised efficacy upon progression.