The National Institute of Diabetes & Digestive & Kidney Diseases

Interstitial Cystitis Clinical Trials Group: Interventional Trial of BCG

Ten clinical centers (see below) in the United States and Canada are studying a promising therapy for interstitial cystitis (IC), a chronic and painful bladder condition that mostly targets women. The IC Clinical Trials Group study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and is testing whether the bacterium Bacillus Calmette-Guérin (BCG) will relieve the pelvic pain and frequent urination that are hallmarks of IC.

Approximately 260 participants were randomly assigned to have either a BCG or saline solution temporarily placed in the bladder during each of six clinic visits. Neither doctors nor patients know who received the BCG; this will be disclosed at the end of the study. Patients whose symptoms were not relieved by the initial series will be openly offered BCG.

BCG is a vaccine for tuberculosis and a treatment for superficial bladder cancer. Exactly how BCG works in the bladder is still a mystery, but research suggests it may stimulate a protective immune response and downplay a harmful one in the IC bladder. If BCG fulfills the promise of earlier studies, it could profoundly alter disease management and patients' quality of life, which has been described as worse than being on kidney dialysis. Symptoms are so severe that only about 50 percent of an estimated 1 million IC patients are able to work full time. The disorder accounts for $1.7 billion in lost wages and medical expenses. About a quarter of patients are younger than 30 years.

Study results are expected to be available March 2004.