Randomized, double-blind, dose-ranging study of pentosan polysulfate sodium for interstitial cystitis

Abstract

Objectives: To compare the current recommended dose of pentosan polysulfate sodium (PPS) with doses two to three times higher.

Methods: We evaluated three dosages (300, 600, and 900 mg) of PPS in a randomized, double-blind, double-dummy, parallel-group, multicenter, 32-week study. Adults (n = 380) with a diagnosis of interstitial cystitis (IC) as determined by a positive cystoscopic examination combined with bladder pain and urgency or a history of IC symptoms for at least 6 months were enrolled. Participants completed the Patient's Overall Rating of Symptom Index (PORIS) and the O'Leary-Sant Interstitial Cystitis Symptom Index (ICSI) at baseline (ICSI only) and during follow-up visits at 4, 8, 12, 16, 24, and 32 weeks.

Results: Mean ICSI scores improved significantly during the 32 weeks for all dosages (baseline 11.2, 11.9, and 11.9 to endpoint 8.2, 8.1, 8.6 for 300, 600, and 900 mg, respectively; P <0.001) but the response to treatment was not dose dependent (no statistically significant difference in response among the three dosages). At baseline, 3.2%, 62.2%, and 34.6% reported mild, moderate, and severe symptoms, respectively, as assessed by the ICSI. At study end, 27.5%, 56.9%, and 15.7% reported mild, moderate, and severe symptoms, respectively. The PORIS scores improved within 4 weeks with 15.8% to 21.1% of all patients classified as responders (50% or greater improvement on PORIS). At 32 weeks, 49.6%, 49.6%, and 45.2% of all patients were responders at a dose of 300, 600, and 900 mg, respectively. Most adverse events were mild and resolved without intervention.

Conclusions: For all three dosages of PPS, a clinically significant but similar response was demonstrated. The duration of therapy appears to be more important than the dosage.