Since the first report in 1976, the accumulated clinical evidence supports the use of intravesical BCG therapy as one of the standard methods of managing intermediate- and high-risk NMIBC. Although the precise immunological mechanism of BCG therapy is still unclear, our understanding is increasing of reactions induced by BCG complexes, including infection of urothelial cells or bladder cancer cells, induction of immune responses, and induction of antitumor effects. A number of clinical and preclinical studies have been conducted to overcome the limitations of intravesical BCG therapy. Among them, development of a non-live bacterial agent is one of the most promising candidates for a future substitute for live BCG. Read more.