IMMUNOTERAPIA ENDOVESCICALE CON INTERLEUCHINA-2 RICOMBINANTE (RIL-2) NEL CA. VESCICALE DI BASSO STADIO. STUDIO DI FASE IB

Twenty-four patients (22 males and 2 females; age range 37-75 years, mean 58 years, median 63) with transitional cell carcinoma of the bladder (Ta-T1, N0, M0; G1-2) were entered into the study between September 1989 and July 1991. An induction course of 10 daily intravesical instillations was administered with the tumour in place using four different doses of recombinant interleukin-2 (rIL-2) ranging from 3 to 18 x 10⁶ IU/day. Transurethral resection of the bladder tumour (TUR-BT) was carried out 10-14 days after the last rIL-2 dose. One month later, a first maintenance course (10 daily intravesical instillations of rIL-2) was started at the dose of 6 x 10⁶ IU/day in all patients, and repeated every 4 months for one year. Objective clinical response to the induction course of rIL-2 was evaluated by ultrasound sonography and cystoscopy just before transurethral resection. Physical examination, laboratory tests and cystoscopy were carried out bimonthly throughout the study. No laboratory or clinical toxicity was observed in any patient. Partial regression of the primary tumour was observed in 5 out of 24 patients; 19 patients were considered as 'stable disease'; no tumour progression occurred. Twenty-four patients are evaluable for response with a follow-up ranging from 3 to 24 months (mean 12.5, median 11). Local tumour relapses were diagnosed in 6 out of 24 patients between 3 and 7 months (median 4) after TUR-BT; 18 patients remain with no evidence of disease. Regression of the primary tumour, observed in some patients, suggests an interesting biological and clinical activity of rIL-2 intravesical immunotherapy on bladder cancer. No definitive conclusions can yet be drawn on the effect of this treatment schedule on local tumour recurrence rate.