Long-term experience with pentosanpolysulfate in interstitial cystitis

An oral preparation of pentosanpolysulfate sodium (PPS) was recently approved by the Food and Drug Administration for interstitial cystitis (IC). Previously published articles have documented improvement in symptoms in 28% to 63% of patients, but no long-term studies have been published. No unique characteristics except for Hunner's ulcer have been found in patients experiencing relief from PPS. We report our experience with PPS following patients up to 116 months and analyze baseline parameters in an attempt to characterize long-term responders.

Baseline and follow-up data from 97 patients with IC and enrolled in a compassionate use study with PPS at the University of Wisconsin from 1987 to 1995 are analyzed. Previous treatments had failed, and patients had to pay for PPS. Patients continuing treatment with PPS were monitored every 3 months with questionnaires and laboratory tests. In 1996 an update on medication and a questionnaire developed by the National Institutes of Health Interstitial Cystitis Database were sent to patients who had discontinued treatment.

By the end of the study period 11 (11.3%) of the patients were still taking PPS, with 6 (6.2%) doing so continuously for more than 18 months. Three (3%) patients who discontinued PPS were in long-term remission. An additional 15% had remission for a substantial period. Except for a weak correlation between less constant pain (P = 0.0439), no correlations were found between baseline parameters and duration of treatment with PPS.

On a long-term basis, between 6.2% and 18.7% of patients with IC benefit from PPS. The only baseline factor predicting response to PPS was less constant pain.