BERKELEY, CA (UroToday.com) - Cyclosporin in a daily divided dose of 3mg per kilogram per day was compared with sodium pentosanpolysulfate (Elmiron®) 100mg three times daily in 64 patients with PBS/IC over 6 months of treatment. The Finnish group led by Sairanen reported their findings using a primary endpoint of daily micturition frequency and secondary endpoints of maximal bladder capacity mean voided volumes, nocturia, global response assessment, and VAS and O'Leary Sant symptom scores. About half of the patients in each treatment cohort had failed at least 3 prior types of PBS/IC therapy.

The primary endpoint was a very optimistic one: reduction of micturition frequency in 24 hours by half. This was met by 34% of the cyclosporine patients and none of the Elmiron® patients. Cyclosporin was also significantly more effective than Elmiron® in all other objective and subjective parameters measured. The global response assessment, the only parameter that showed significant improvement in pivotal pentosanpolysulfate trials, was positive (much better or completely cured) in 13/% of pentosanpolysulphate patients versus 59% of cyclosporine patients. At 6 months, patients were asked if they wanted to proceed with the current treatment at their own cost. A total of 19 patients continued on cyclosporine treatment and 4 patients continued on Elmiron®.

Cyclosporin had a higher adverse event profile than pentosanpolysulfate, and two patients required dose reduction because of elevation in diastolic blood pressure. Although cyclosporine side effects were common, the same number of patients still completed the study in both arms, perhaps reflecting the efficacy of the cyclosporine treatment as a motivator. Close monitoring of blood pressure and renal function is required in patients on cyclosporine.

The interstitial cystitis clinical research network (ICCRN) of the National Institute of Diabetes, Digestive, and Kidney Disorders is planning to study mycophenolate mofetil (CellCept), hoping it will have similar efficacy with a diminished adverse event profile. The Finnish researchers have opened up a new avenue for the treatment of PBS/IC, and further studies are needed to confirm their exciting results.

J Urol. December; 174:2235-2238