- Connaught strain of bacillus Calmette-Guérin proved superior.
- Patients treated with Tice strain may be at increased risk for recurrence.
- Genetic strain differences rather than dose and preparation at cause.
CHICAGO — Use of the Connaught strain of bacillus Calmette-Guérin, an adjuvant immunotherapy used in the treatment of non-muscle-invasive bladder cancer, significantly reduced cancer recurrence compared with the Tice strain of bacillus Calmette-Guérin, according to data presented at the AACR Annual Meeting 2012, held here March 31 – April 4.
Cyrill A. Rentsch, M.D., Ph.D., of the division of urology at the University of Basel in Switzerland, presented the phase III data, which represent the potential for a shift in the standard-of-care treatment for non-muscle-invasive bladder cancer.
Bacillus Calmette-Guérin (BCG) was originally developed as a vaccine for tuberculosis but has also been the standard of care for the treatment of noninvasive bladder cancer for more than 30 years. Currently, at least eight strains of BCG are used in treating bladder cancer.
“This is the first study demonstrating that different BCG strains lead to different clinical outcomes in the treatment of bladder cancer,” Rentsch said.
He and his colleagues prospectively compared the efficacy of the Connaught and Tice strains in preventing recurrences and progression of cancer. They recruited and randomly assigned 149 patients to six weekly injections of Tice or Connaught. All patients had undergone surgery to remove visible bladder tumors.
After a median follow-up of 25 months, the five-year recurrence-free survival rate for all patients was 61 percent. Patients who underwent treatment with Connaught had significantly fewer recurrences compared with patients treated with Tice. The five-year recurrence-free survival for patients treated with Connaught was 75 percent compared with 46 percent for patients treated with Tice.
“At five years, this results in a more than twofold improvement in the recurrence rate in favor of BCG Connaught,” Rentsch said. “Based on its common use, we estimate that more than 20 percent of the worldwide population is at risk to receive treatment with BCG Tice, a treatment that, based on our findings, is less effective in reducing recurrences than BCG Connaught.”
These results have the potential to substantially improve the course of disease in many patients with non-muscle-invasive bladder cancer, according to Rentsch.
“As an example of clinically successful immunotherapy, it is a must to further dissect and understand the specific mechanisms underlying BCG immunotherapy,” Rentsch said. “The genetic differences identified between the two strains might represent a start for further studies.”
The study was funded clinically by the department of urology at the University Hospital of Bern, Switzerland, and the Swiss Group for Clinical Cancer Research. Translational funding included the Swiss National Foundation, Inserm, La Ligue contre le Cancer and Institute Pasteur in Paris.
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About the AACR
Founded in 1907, the American Association for Cancer Research (AACR) is the world’s first and largest professional organization dedicated to advancing cancer research and its mission to prevent and cure cancer. AACR’s membership includes 34,000 laboratory, translational and clinical researchers; population scientists; other health care professionals; and cancer advocates residing in more than 90 countries. The AACR marshals the full spectrum of expertise of the cancer community to accelerate progress in the prevention, biology, diagnosis and treatment of cancer by annually convening more than 20 conferences and educational workshops, the largest of which is the AACR Annual Meeting with more than 18,000 attendees. In addition, the AACR publishes seven peer-reviewed scientific journals and a magazine for cancer survivors, patients and their caregivers. The AACR funds meritorious research directly as well as in cooperation with numerous cancer organizations. As the Scientific Partner of Stand Up To Cancer, the AACR provides expert peer review, grants administration and scientific oversight of individual and team science grants in cancer research that have the potential for patient benefit. The AACR actively communicates with legislators and policymakers about the value of cancer research and related biomedical science in saving lives from cancer.
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