Phase I pharmacokinetic study of a single intravesical instillation of gemcitabine administered immediately after transurethral resection plus multiple random biopsies in patients with superficial bladder cancer.

Abstract

In this phase I study we determined the pharmacokinetic and toxicity profiles of a single intravesical instillation of gemcitabine administered immediately after complete transurethral resection (TUR) plus multiple random biopsies. Ten patients with superficial bladder cancer clinically staged as Ta/T1 with no carcinoma in situ were included. A single dose of gemcitabine was administered intra-vesically immediately after TUR plus 6 random biopsies. Five patients received 1,500 mg and 5 received 2,000 mg diluted in 100 ml saline. Retention time in the bladder was 60 minutes. Concentrations of gemcitabine and dFdU (2',2'-difluoro-2'-deoxyuridine) were determined by high pressure liquid chromatography assay. Treatment was clinically well tolerated in all patients. Two patients in the 1,500 mg group had minimal hipogastric discomfort and 1 in the 2,000 mg group had grade 1 bladder spasms. There was no remarkable systemic toxicity on hematology or biochemistry at any dose level on day 12 or 30. One patient per dose level showed tumor recurrence on 3-month repeat cystourethroscopy. Mean maximum gemcitabine concentration was 1.8 microg/ml and the mean last AUC was 158 microg/ml*minute. There was large interpatient variability but no significant differences between the 2 dose levels. Single intravesical instillation of gemcitabine immediately after TUR and multiple random biopsies for superficial bladder cancer are a safe and well tolerated treatment. The favorable toxicity and pharmacokinetic profiles of intravesical gemcitabine support future phase II studies with this agent.