Intravesical BCG therapy has been for years, the standard of care in nonmuscle-invasive bladder cancer. But upon recurrence/relapse, radical cystectomy is imposed, due to the paucity of other therapeutic options. Immunotherapy has been revolutionizing cancer treatment, and its indications continue to broaden. It has been approved for the treatment of advanced urothelial cancer of the bladder, mainly as a second-line therapy. Its activity is being studied in nonmuscle-invasive bladder cancer that is not responsive to BCG; we herein report the trials investigating these checkpoint inhibitors (pembrolizumab, nivolumab, atezolizumab, durvalumab and avelumab) in this particular setting.
Keywords: BCG refractory; BCG unresponsive; checkpoint inhibitors; immunotherapy; nonmuscle-invasive bladder cancer; pembrolizumab.
Lay abstract Administration of BCG vaccine inside the bladder has, for a long time, been the treatment of bladder cancer that has not invaded the layers of this organ, or at least has not arrived at the muscle of the bladder. However, when this cancer recurs or has not responded to this type of treatment, radical cystectomy (i.e., complete removal of the bladder) is imposed. While the latter is associated with significant decrease in quality of life, and when immunotherapy (therapy that relies on immune white blood cells combatting tumor cells) has shown promising results in metastatic bladder cancer, trials are ongoing to prove the potential benefits of this novel therapy in confined, but not responsive to BCG, bladder cancer. In this article, we report these studies, highlighting the most important ones that are, if not already, leading to approval of immunotherapy in this setting.