Possible new treatment for bladder cancer using a mycobacterium

Mycobacteria are the only bacteria used in cancer treatment. The administration of the bacterium Mycobacterium bovis (BCG), is the current treatment for superficial bladder cancer. It is inserted directly into the bladder through a catheter. BCG prevents new tumours from appearing, but despite its efficacy it has many adverse side effects, the most serious being BCG infections that need to be treated with antituberculous drugs.

A study on the characteristics of a wide group of mycobacteria begun seven years ago by the Mycobacteria Research Group, led by Dr Esther Julián, of the Department of Genetics and Microbiology, Universitat Autònoma de Barcelona, has discovered that one of these, Mycobacterium brumae (M.brumae), is able to reduce the growth of tumour cells in the bladder and activate an immune response.

Pre-clinical studies using mouse models of bladder cancer have demonstrated the efficacy of the mycobacterium M. brumae in the treatment of this disease. Mice with bladder tumours that are treated with M. brumae in the same way as patients survive longer than untreated mice and, what is more, in larger numbers than those treated with the usual mycobacterium: BCG.

The studies conducted at the UAB have shown that M. brumae is not pathogenic, presenting no risk of causing infections, which means it would have fewer adverse side effects on patients than BCG.

Furthermore, the fact that M. brumae is a rapid-growth, non-pathogenic mycobacterium makes it easier and quicker to produce on a large scale than BCG, which is significant given that in the last few years BCG production problems have led to supply issues for certain bladder cancer patients.

"Our results suggest that Micobacterium brumae is an ideal candidate to replace the current BCG treatment for superficial bladder cancer," concludes UAB researcher Esther Julián.

The study, published in the journal European Urology Focus, was conducted in collaboration with Dr Rosa M. Rabanal of the Murine and Comparative Pathology Unit, Department of Animal Medicine and Surgery, UAB, and with the group Bacterial Infections and Antimicrobial Therapies led by Dr Eduard Torrents, of the Institute for Bioengineering of Catalonia (IBEC).