Treatment of superficial bladder tumors with intravesical recombinant interferon alpha-2a.

In a prospective study, the toxicity and efficacy of an instillation therapy with recombinant interferon alpha-2a (rIFN-alpha-2a) were evaluated in 12 patients with superficial bladder tumors. Treatment consisted of 8 weekly instillations of 54 X 10(6) IU rIFN-alpha-2a in 50 ml saline. Two weeks after completion of the instillation therapy, the tumor status was assessed with cystoscopy, biopsy and bladder wash-out cytology. Two partial responses, 1 no change and 2 progressive disease were seen in the 5 patients with TA tumors. In the 4 patients with carcinoma in situ, 1 complete response, 1 partial response and 2 no change were observed. Three patients suffered from carcinoma in situ and superficial papillary tumors, 1 showed complete response of the carcinoma in situ but no change of the TA tumor, the other 2 patients showed progressive disease. Three patients with partial response received a follow-up combination therapy with interferon intravesically and etretinate orally (25 mg/day). These patients presented progressive disease or no change 10 weeks after starting the follow-up combination therapy. During the treatment period, no side effects of interferon or changes of the serum interferon levels were observed. The treatment results are considered unsatisfactory; nevertheless, some activity after intravesical administration of interferon (mainly in patients with carcinoma in situ) could be demonstrated. Since the cytotoxic and antiproliferative effects seem to be dose-dependent, further studies might be done using higher interferon dosages and shorter treatment intervals.