Exposure of peripheral blood mononuclear cells from cancer patients to high concentrations of recombinant IL-2 in vitro has been observed to result in the generation of cells capable of causing lysis of a variety of tumor cells. This study is an attempt to utilize such cells in the therapy of cancer in humans. Previous studies in the Surgery Branch of the National Cancer Institute demonstrated significant antitumor activity of these cells when administered concurrently with IL-2. On our initial trial (see last year's summary), 30 patients were treated with a bolus IL-2 regimen and 27 were evaluable for response, 2 of whom had partial responses. In order to evaluate the toxicity of a continuous infusion IL-2 plus LAK cell regimen and to determine in a preliminary fashion its antitumor efficacy, we have performed a trial using 5 days of continuous infusion IL-2 priming, 3 days of leukapheresis with LAK cells generated from each of these days, and then 5 days of continuous infusion IL-2 along with reinfusion of the LAK cells. To date, 20 patients have been treated with this regimen with 12 patients evaluable for response. Toxicities have been quantitatively similar to the bolus regimen but qualitatively significantly less severe. One of three patients with renal cell cancer has had a partial response. There have been no responses in patients with other diseases.
