Phase II study of oral metformin for intravesical treatment of non- muscle-invasive bladder cancer

Non-muscle-invasive bladder cancer (NMIBC) is the most common neoplasm of the urinary tract, with ~3,700 new cases and a prevalence of ~32,000 patients in the Netherlands in 2016. Despite current treatments, it is associated with high risk of recurrence and/or progression. Metformin is effective against bladder cancer in animal models. The objective of this multicenter, open-label, phase 2 study is to determine the complete response rate of bladder cancer to administration of oral metformin for 3 months in ablating a marker tumour deliberately left following transurethral resection of multiple, papillary tumours in the bladder. Secondary outcomes are the partial response rate, overal saftety of metformin and the duration of time to recurrence after marker lesion resection.