In order to establish an optimum mode for systemic administration of recombinant
interleukin 2 (rIL-2), the effects of rIL-2 (Biogen, Switzerland) on lymphocyte-mediated cytotoxicity against established
renal carcinoma cell line Caki 1. KU-2 and freshly prepared
renal carcinoma cells were studied. Augmentation of cell-mediated cytotoxicity by rIL-2 was dose- and time-dependent. The results indicated that the optimal dose of rIL-2 was 100 to 500 units (Jurkat units)/ml, and that cytotoxicity increased significantly even at a low concentration such as 4 units/ml. We thus chose daily administration of multiple repeated dose for inpatients. To prevent withdrawal from the
therapy as a result of un-tolerable adverse effects, the daily dose was set at 1 x 10(6) units, and rIL-2 was given to 17 patients with advanced
genitourinary cancer. Two-hour
intravenous drip infusions containing 5 x 10(5) units of rIL-2 was given daily two times to inpatients and after at least 28 days of this mode of administration,
subcutaneous injection at a dose of 1 x 10(6) units was given 6 days a week to outpatients. In 12 patients with
renal cell carcinoma, 2 patients showed complete response; 1 patient partial response; 7 patients no change, and 2 patients progressive disease. In patients with
carcinoma of the prostate or bladder
carcinoma, all patients were no change from criteria of Japan Society for
Cancer Therapy, however, marked decrease in serum
acid-phosphatase and improvement of performance status in 1 patient with
carcinoma of the prostate, and massive
necrosis of
tumor accompanied by disappearance of severe leg
edema in a patient with bladder
carcinoma were observed.