Multiple cycles of constant infusion recombinant interleukin-2 in adoptive cellular therapy of metastatic renal carcinoma.

Twenty patients were treated with metastatic renal cell cancer with 5-day cycles of constant infusion recombinant interleukin-2 (rIL-2) at 3 X 10(6) U/m2/day and with infusion of in vitro activated autologous mononuclear cells. The initial eight patients completed all rIL-2 and cellular therapy in a single 25-day treatment period. The subsequent 12 patients entered a 6-month treatment program involving two separate 15-day cycles of cellular therapy followed by four monthly cycles of maintenance rIL-2. Among eight patients in the 25-day treatment program, there were two with partial response (PR) and one with minor response (MR). None of these responses exceeded 2 months in duration. Among the 12 patients undergoing recycling of therapy, there were two with complete response (CR), two with PR, and one with MR. All four patients with CR or PR in this group demonstrated continuing response with recycling of treatment and none relapsed while receiving maintenance interleukin-2. Three remain in remission at 10, 11, and 12 months. These pilot data confirm that patients can tolerate multiple cycles of adoptive immunotherapy involving constant infusion rIL-2 and suggest that recycling of therapy is necessary to achieve clinically meaningful results.