Which Bacillus Calmette-Guérin (BCG) strains are used as immunotherapy for bladder cancer?

Updated: Nov 12, 2019
  • Author: Gary David Steinberg, MD, FACS; Chief Editor: Bradley Fields Schwartz, DO, FACS  more...
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Answer

Answer

The original bacillus Calmette-Guérin (BCG) strain was developed at the Pasteur Institute from an attenuated strain of Mycobacterium bovis. Subcultures were made and sent to other parts of the world. Two BCG products are commercially available in the United States. The Tice strain, which is a substrain of the original Pasteur product, is manufactured by Organon Pharmaceuticals. The TheraCys strain is made by Aventis/Pasteur. These products, in addition to the Tokyo 172 substrain and the Danish substrain, are available in countries other than the United States.

No one product has been shown to have consistent clinical superiority. BCG viability is an important consideration for the vaccine to be effective. This viability is measured in colony-forming units (CFUs). A vaccine that contains no or very few live organisms would be clinically ineffective. One dose, either an ampule or vial, may vary in weight from one product to another, but the CFU should be similar. Tice BCG has 1-8×10-8 CFUs. TheraCys has 10.5 +/-8.7×10-8 CFUs.

In a study that compared Tokyo172 with the Connaught vaccines, Ikeda et al found that the Tokyo172 vaccine had 48.77 +/-5.43 CFUs per dose, while the Connaught strain had 3.77 +/-1.45 CFUs. [5] This implies that a smaller dose of Tokyo172 is likely to be as effective as a much larger dose of the Connaught strain.


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