Background: Intravesical bacillus Calmette-Guérin (BCG) is the gold standard immunologic agent for treating patients with high-grade non-muscle invasive bladder cancer (NMIBC). Nevertheless, relapse rates remain high and BCG unresponsive NMIBC often requires bladder removal. Preclinical data suggest that priming with percutaneous BCG vaccine could improve response to intravesical BCG. Methods: A single-arm trial (NCT02326168) was performed to study the safety, immunogenicity, and preliminary efficacy of priming. Percutaneous BCG was given 21 days prior to intravesical BCG instillation in patients (n = 13) with high-risk NMIBC. Immune responses were monitored and compared to a sequentially enrolled cohort of nine control patients receiving only intravesical BCG. The effect of BCG on natural killer (NK) and γδ T cell in vitro cytotoxicity was tested. γδ T cell subsets were determined by T cell receptor gene expression with NanoString. Results: Priming was well tolerated and caused no grade ≥3 adverse events. The 3-month disease-free rate for prime patients was 85% (target goal ≥ 75%). Priming boosted BCG-specific immunity at 3 months and increased the activation status of in vitro expanded circulating NK and γδ T cells and their cytotoxicity against bladder cancer cells through receptor NKG2D. BCG enhanced the cytotoxicity of NK and γδ T cells against K562, RT4, and UM-UC6 but not against T24, UM-UC-3, or UM-UC-14 cells. Infiltrating γδ T cell subsets identified in the bladder includes γ9δ2 and γ8δ2. Conclusions: BCG priming is safe and tolerable. Poor sensitivity to NK and γδ T cell cytotoxicity by some bladder tumors represents a potential BCG-resistance mechanism.
Oncoimmunology. 2019 May 25*** epublish ***
Niannian Ji, Neelam Mukherjee, Edwin E Morales, Maggie E Tomasini, Vincent Hurez, Tyler J Curiel, Getahun Abate, Dan F Hoft, Xiang-Ru Zhao, Jon Gelfond, Sourindra Maiti, Laurence J N Cooper, Robert S Svatek
Department of Urology, School of Medicine, the University of Texas Health Science Center San Antonio, San Antonio, TX, USA., Department of Medicine/Hematology & Medical Oncology, School of Medicine, the University of Texas Health Science Center San Antonio, San Antonio, TX, USA., Department of Internal Medicine, Division of Infectious Diseases, Allergy and Immunology, Saint Louis University Edward A. Doisy Research Center, .St. Louis, MO, USA., Department of Epidemiology and Biostatistics, School of Medicine, the University of Texas Health Science Center San Antonio, San Antonio, TX, USA., Pediatrics, M.D. Anderson Cancer Center, Houston, TX, USA.