The Rideau trial is a multi-centre, prospective, randomized phase I/II trial to determine whether the local cystoscopic injection of tremelimumab into the bladder wall in combination with systemic administration of durvalumab in localized bladder cancer will stimulate an effective anti-tumour immune response with minimal systemic immune response and clinical toxicity. The study will be broken down into a dose escalation phase, to determine the recommended phase II dose of each drug in combination, and a dose expansion phase, to demonstrate an early signal of treatment efficacy (complete response at 6 months) in patients with BCG-unresponsive carcinoma in situ of the bladder. A maximum of 48 patients will be enrolled from 3 participating sites across Canada. All patients with histologically proven bladder cancer scheduled to undergo radical cystectomy at the trial hospital will be eligible for the dose escalation phase, while patients must have histologically proven, recurrent urothelial carcinoma in situ of the bladder to be eligible for the dose expansion phase. The dose escalation phase will run with between 12-36 patients who will receive 18 weeks of follow-up to determine the recommended phase II dose. Twelve patients will be enrolled in the dose expansion phase. These patients will receive follow-up every 4 weeks for 48 weeks, and then every 3 months for a total follow-up period of 24 months.
We will conduct a Phase I trial testing whether local cystoscopic injection of tremelimumab into the bladder wall in combination with systemic administration of durvalumab in localized bladder cancer will stimulate an effective anti-tumour immune response with minimal systemic immune response and clinical toxicity.