Therapeutic Cancer Vaccines: Vaccine Against Bladder Cancer

Judicious work carried out at Memorial Sloan Kettering Cancer Center (MSKCC) in the 1950s led by an accomplished physician-scientist, Dr. Lloyd Old identified BCG as a therapeutic vaccine against a large panel of cancers.¹² Among these, early-stage non-metastatic bladder cancer was identified to have shown high efficacy in cancer cell elimination. The findings were later confirmed by the National Cancer Institute (NCI). The vaccine is injected directly into the cancer-inflicted bladder, triggering an inflammatory response that activates a type of T lymphocyte called CD4+ T cells.

The mechanism of action regarding how BCG works against bladder cancer cells remains elusive. Some point out that activated CD4+ T cells secret a powerful cytokine called interferon to eliminate bladder cancer cells. Others propose infection of cancer cells by BCG triggers an immune response that exerts an anti-tumor effect. It is interesting that patients who have received BCG vaccination earlier in their life showed 80% of 5-year relapse-free survival (RFS), whereas, for those who did not receive BCG earlier, the vaccine led to only 42% of 5-year RFS.¹³ This implies that immune memory from early BCG vaccination likely plays a role in more efficient tumor antigen recognition.