Phase II study to investigate the ablative efficacy of intravesical administration of gemcitabine in intermediate-risk superficial bladder cancer (SBC)

OBJECTIVE: Phase I studies have so far demonstrated that intravesical Gemcitabine up to a 40 mg/ml concentration is well tolerated and has a substantial ablative activity on high-risk BCG refractory SBC. New treatment options are needed for intermediate-risk SBC recurring after conventional intravesical treatments. The purpose of the present study was to investigate the ablative efficacy of intravesical Gemcitabine on intermediate-risk SBC. METHODS: The study was designed as a two-stage phase II trial, with a sample size of 39 patients. The efficacy of intravesical Gemcitabine at a concentration of 40 mg/ml (2000 mg in 50 ml saline solution) administered weekly for 6 weeks was assessed on a single marker tumour left in the bladder after a complete TUR of all other lesions. Patients underwent TUR or biopsy at the site of the marker lesion 2 weeks after completion of the treatment. RESULTS: Complete response was observed in 22 out of 39 patients (56%). No progression was observed among the 17 non-responders. Neither systemic nor local side effects generally exceeded grade I toxicity. CONCLUSION: The ablative effect of Gemcitabine produced a higher number of responses than the minimum required by the protocol to indicate a significant probability of drug efficacy. It is worth testing the drug in phase III trials to assess for durability of response.