Pentosan Polysulfate Sodium for Treatment of Interstitial Cystitis/Bladder Pain Syndrome: Insights from a Randomized, Double-Blind, Placebo Controlled Study

PURPOSE: We compared the efficacy and safety of the currently recommended dose of pentosan polysulfate sodium with a third of the daily dose and with placebo. MATERIALS AND METHODS: In this multicenter, double-blind, randomized, placebo controlled study 368 adults with interstitial cystitis/bladder pain syndrome, defined as an ICSI total score of 8 or greater and a score of greater than 0 on the 4 ICSI component items, received pentosan polysulfate sodium 100 mg once daily or 3 times daily, or matching placebo for 24 weeks. Study eligibility was not based on cystoscopy findings. ICSI was administered at baseline, and at weeks 4, 8, 12, 18 and 24. Unblinded interim analysis performed at 6 years with 54% of the target number of 645 patients enrolled resulted in early study termination. RESULTS: There was no statistically significant difference between the pentosan polysulfate sodium group and the placebo group or between the 2 pentosan polysulfate sodium groups for the primary end point, defined as responder achieving a 30% or greater reduction from the baseline ICSI total score at study end. This primary end point was achieved by 48 of 118 patients (40.7%) in the placebo group, and by 51 of 128 (39.8%) and 52 of 122 (42.6%) in the pentosan polysulfate sodium 100 mg once daily and 3 times daily groups, respectively. Pentosan polysulfate sodium was well tolerated with a similar percent of patients (range 10.2% to 13.3%) across the groups discontinuing due to an adverse event. CONCLUSIONS: Results of this study in a broad population of patients with symptoms consistent with interstitial cystitis revealed no treatment effect vs placebo for pentosan polysulfate sodium at the currently established dose or at a third of the daily dose.