A phase I study of intravesical continuous perfusion of recombinant interleukin-2 in patients with superficial bladder cancer.

A Phase I study was started to evaluate the locoregional and/or systemic toxic effects of the continuous perfusion of recombinant interleukin-2 (rIL-2) in superficial bladder cancer. Three different dose levels were used: 3 x 10(6) IU/day (3 patients), 9 x 10(6) IU/day (3 patients) and 27 x 10(6) IU/day (3 patients). Two patients (one treated with 3 x 10(6) and another with 27 x 10(6) IU/day of rIL-2) had hematuria after the end of the treatment, one patient had fever (grade I) and 7 of 9 patients experienced hypotension (grade I-II). All effects were not dose related. Routine laboratory tests indicated that no significant variations of biochemical parameters occurred. A phenotypic analysis of white blood cells detectable in the bladder, showed an evident locoregional activation of lymphoid cells. In particular, T lymphocytes expressed activation antigens (such as CD25 and HLA-DR) following treatment with rIL-2. A 6- to 12-month clinical follow-up, showed that all patients but one (which recurred after 5 months) are alive and disease-free. This therefore indicates that the locoregional perfusion of rIL-2 is safe and gives clinical results similar to those obtained using Calmette-Guérin bacillus locoregional instillation, in patients who underwent a transurethral resection of superficial bladder cancer.