Treatment and Duration Effect of Pentosan Polysulfate Sodium (PPS) in Participants With Knee Osteoarthritis Pain

This is an observational study to determine duration of treatment effect and assess long-term safety up to 52 weeks post PPS use for 6 weeks in parent study (PARA\_OA\_002). The duration of treatment effect will be evaluated by the OMERACT-OARSI responder criteria for knee OA. Eligible participants will be enrolled in Study PARA\_OA\_006 at the completion of the parent study PARA\_OA\_002. There will be no intervention in this observational study. Participants will attend screening (visit 1), three phone visits at 8, 16, and 24 weeks, and an EOS (end of study) visit 34 weeks at the site, a total of 5 visits. Participants questionnaires include WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) NRS 3.1 Index, PGIC (Patients Global Impression of Change), WPAI (Work Productivity and Activity Impairment) and quality of life SF-36.