For non-muscle-invasive bladder cancer, use of the Connaught strain of bacillus Calmette-Guérin (BCG) may be more effective at preventing recurrences than the Tice strain of BCG. These results—from a Phase III clinical trial—were presented at the 2012 annual meeting of the American Association for Cancer Research.

Each year in the United States, more than 55,000 men and more than 17,000 women are diagnosed with bladder cancer. Thanks to improvements in treatment, bladder cancer patients are living longer than ever before. It is estimated that there are more than 500,000 bladder cancer survivors in the U.S. today.

For people with early bladder cancer (cancer that has not yet reached the bladder muscle), treatment generally involves surgery or other treatment to remove cancer from the bladder. To reduce the risk that the cancer will come back (recur), patients may also be treated with BCG or chemotherapy administered directly into the bladder.

BCG is an immunotherapy that is a weakened form of a bacterium. BCG is instilled directly into the bladder through the urethra and exerts its anti-cancer effect by stimulating the body’s immune system to kill cancer cells. Different strains of BCG are available for use in the treatment of bladder cancer, and it’s possible that these different strains could differ in effectiveness.

To compare two strains of BCG that are commonly used in the United Statesand Europe—the Connaught strain and the Tice strain—researchers in Europe conducted a Phase III clinical trial among 149 patients with early bladder cancer. Half the patients were treated with the Connaught strain and half were treated with the Tice strain.

Five-year survival without a recurrence was 75 percent among patients treated with the Connaught strain of BCG and 46 percent among patients treated with the Tice strain. Side effects did not vary significantly by type of BCG.

These results suggest that the Connaught strain of BCG may be more effective than the Tice strain for the treatment of non-muscle-invasive bladder cancer.

Reference: RentschCA, Birkhauser F, Studer UE et al. A randomized phase III study comparing the efficacy of bacillus Calmette-Guérin strain Tice versus Connaught for immunotherapy of non-muscle invasive bladder cancer. Paper presented at: 2012 annual meeting of the American Association for Cancer Research; March 31-April 4, 2012; Chicago,IL. Abstract 2691.