Pentosan Polysulfate Inhibits Attachment and Infection by SARS-CoV-2 In Vitro: Insights into Structural Requirements for Binding.

Two years since the outbreak of the novel coronavirus SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) pandemic, there remain few clinically effective drugs to complement vaccines. One is the anticoagulant, heparin, which in 2004 was found able to inhibit invasion of SARS-CoV (CoV-1) and which has been employed during the current pandemic to prevent thromboembolic complications and moderate potentially damaging inflammation. Heparin has also been shown experimentally to inhibit SARS-CoV-2 attachment and infection in susceptible cells. At high therapeutic doses however, heparin increases the risk of bleeding and prolonged use can cause heparin-induced thrombocytopenia, a serious side effect. One alternative, with structural similarities to heparin, is the plant-derived, semi-synthetic polysaccharide, pentosan polysulfate (PPS). PPS is an established drug for the oral treatment of interstitial cystitis, is well-tolerated, and exhibits weaker anticoagulant effects than heparin. In an established Vero cell model, PPS and its fractions of varying molecular weights inhibited invasion by SARS-CoV-2. Intact PPS and its size-defined fractions were characterized by molecular weight distribution and chemical structure using nuclear magnetic resonance spectroscopy and liquid chromatography-mass spectrometry, then employed to explore the structural basis of interactions with SARS-CoV-2 spike protein receptor-binding domain (S1 RBD) and the inhibition of Vero cell invasion. PPS was as effective as unfractionated heparin, but more effective in inhibiting cell infection than low-molecular-weight heparin (on a weight/volume basis). Isothermal titration calorimetry and viral plaque-forming assays demonstrated size-dependent binding to S1 RBD and inhibition of Vero cell invasion, suggesting the potential application of PPS as a novel inhibitor of SARS-CoV-2 infection.

Efficacy of pentosan polysulfate for the treatment of interstitial cystitis/bladder pain syndrome: results of a systematic review of randomized controlled trials.

Background: Among the numerous therapeutic approaches used in the treatment of interstitial cystitis/bladder pain syndrome (IC/BPS) few have been assessed with a sufficient level of evidence. The safety and efficacy of pentosan polysulfate sodium (PPS) has been shown in several open-label and comparative clinical trials with different populations including two meta-analyses. In the context of the approval procedure of PPS for the treatment of IC/BPS by the European Medicines Agency we updated the findings of the previous analyses by incorporating the results of the latest studies.Method: Relevant studies based on a systematic review of PubMed/Medline and the Cochrane Library in June 2018 were identified. For completeness control, clinical trial registries were also searched. Only randomized, placebo-controlled clinical trials providing sufficient information to estimate at least one relevant effect size measure to compare the efficacy of PPS versus placebo were included in the analysis.Results: Of the studies identified in the literature search, six randomized placebo-controlled studies met the pre-defined eligibility criteria. Analyses showed no indication of heterogeneity or publication bias. Treatment with PPS led to a statistically significant improvement in the patient's overall response assessment (p < .001), pain (p = .009) and urgency (p = .005).Conclusions: Our meta-analyses confirmed the results of preceding meta-analyses showing that PPS is efficacious compared to placebo in the treatment of bladder pain, urinary urgency and frequency of micturition and thus an evident option for the treatment of IC/BPS symptoms.