Non-muscle invasive bladder cancer (NMIBC) is the most common urinary tract cancer with high chance of relapse. Metformin accumulates in urine and preclinical evidence suggests that metformin has anti-cancer activity against NMIBC.
We hypothesize that oral metformin is a safe and effective intravesical treatment for NMIBC that can improve local control rates.
This is a multi-center, single-arm phase 2 clinical trial. NMIBC patients will undergo a cystoscopy in which all but 1 NMIBC marker lesion is resected. After metformin treatment, the marker lesion’s response is evaluated and resected. A marker lesion study is an accepted, common and safe type of study for clinical trials with novel pharmcological therapies in NMIBC patients.
Adult patients with NMIBC that are eligible for the marker lesion procedure.
INTERVENTION & COMPARATOR
All patients will receive metformin orally 1000 mg twice daily (up to 1500 mg twice daily, based on toxicity and renal function) for 3 months. There is no comparator arm. Because of the marker lesion procedure, every patient is his/her own control.
-Primary: the rate of complete responses of the marker lesion in treated patients.
-Secondary: time to NMIBC recurrence, metformin safety and exploratory translational analyses.
In a two-step design, 49 patients will be enrolled, which allows us to establish a response rate of 50% with a power of 80% and alpha of 5% and to reject with the same power a response rate of <30%.
The primary analysis concerns the objective response rate of metformin in NMIBC (the number of patients that have a complete response divided by the total number of patients).