Protocol for phase I study of pembrolizumab in combination with Bacillus Calmette-Guérin for patients with high-risk non-muscle invasive bladder cancer.

Introduction: The initial treatment for high-risk non-muscle invasive bladder cancer (NMIBC) is endoscopic resection of the tumour followed by BCG therapy. In those who develop recurrence, the standard treatment is radical cystectomy. Despite the advancement in surgical technique and postoperative care, the degree of morbidity associated with radical cystectomy remains high, therefore less invasive treatment modalities are desirable. Therapies targeting the programmed death (PD) pathway have shown promise in urothelial carcinoma. We undertook the current study to determine the safety and efficacy of administering pembrolizumab (a monoclonal antibody targeting the interaction between PD-1 and its ligand) in combination with BCG in high-risk NMIBC.

Methods: This is a single-centre phase I safety and efficacy study of pembrolizumab used in combination with intravesicular BCG treatment for subjects with pathologically documented high-risk NMIBC despite having received two courses of induction therapy or BCG treatment followed by maintenance BCG. Fifteen subjects will be enrolled, patients will receive treatment with 200 mg of pembrolizumab every 21 days, starting 2 weeks from the initial endoscopic resection and continuing for 6 weeks after the final dose of BCG. The primary objective is to determine the safety of administering pembrolizumab at a fixed dose of 200 mg every 3 weeks in conjunction with intravesicular BCG treatment in patients with high-risk NMIBC who have failed previous treatment. Secondary objectives are to determine the 19 weeks and the 3, 12 and 24 months post-treatment completion complete response rate with combined pembrolizumab and intravesicular BCG therapy in the aforementioned patients.

Ethics And Dissemination: The study has been approved by the Institutional Review Board of the Henry Ford Hospital. The results of this study will be published in a peer-reviewed journal and presented at a scientific conference.

Trial Registration Number: NCT02324582.