Mistletoe Plant Extract in Patients with Non Muscle-Invasive Bladder Cancer - Results from a Phase Ib/IIa Single Group Dose Escalation Study.
J Urol. 2015 Apr 21. Epub 2015 Apr 21. PMID: 25910967
PURPOSE: To determine the maximum tolerated dose, safety and effectiveness of intravesical instillation of mistletoe extract after transurethral resection of non-muscle invasive bladder cancer.
MATERIALS AND METHODS: In this single group dose escalation study, patients with non-muscle invasive bladder cancer were treated with weekly instillations of mistletoe extract for 6 weeks. 4 weeks before instillation therapy all patients underwent transurethral resection of bladder tumors. During this procedure a marker tumor was left. 12 weeks after start of instillation therapy a transurethral resection of the marker tumor or biopsy of the former marker tumor location was done so that patients were tumor free when entering the follow up until week 48. During follow up clinical assessment, safety laboratory and cystoscopy was done every 12 weeks.
RESULTS: 36 patients were treated with increasing doses of mistletoe extract. We found no dose limiting toxicities up to a dose of 675 mg of plant extract. Besides local reactions, we saw hints that pyrexia may occur. All adverse events were well manageable. After 12 weeks a marker tumor remission rate of 55.6 % (95 % CI: 38.1 % to 72.1 %). was achieved. After one year, a recurrence rate of 26.3 % (95% CI: 9.1 to 51.2 %) was observed.
CONCLUSIONS: In this study intravesical instillation of mistletoe extract in treatment of patients with non-muscle invasive bladder cancer showed to be safe and well tolerated. Promising data on efficacy were observed and will be further investigated in a phase III study.