Intravesical idarubicin--a phase-I study.

In the scope of a pharmacokinetic and dose-finding study 33 patients received instillations of idarubicin in 11 different doses 1 h before scheduled transurethral resection of bladder cancer. The dose was increased continuously from 5 to 30 mg and the concentration from 0.25-1.5 mg/ml. Idarubicin uptake into tissue was measured along with the serum level. The results showed a clear correlation of the tissue levels with dose and concentration. A significantly higher concentration of idarubicin was measured in the tumor in comparison with the mucosa. Absorption into the muscle was minimal and serum levels were low. Systemic toxicity was not observed, but there were signs of local toxicity in 50% of the subjects. Cytotoxic concentrations in the mucosa were reached at doses of over 15 mg and concentrations of over 0.5 mg/ml. A phase-II study is in preparation.