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

Time from initial response in the parent study (PARA_OA_002) to loss of OMERACT-OARSI (Outcomes Measures in Rheumatology - Osteoarthritis Research Society International) response.

Percentage of participants considered OMERACT- OARSI (Outcomes Measures in Rheumatology - Osteoarthritis Research Society International) responders at each timepoint..

WOMAC NRS 3.1 (Western Ontario and McMaster Universities Osteoarthritis Index) Index Pain average subscale score. Reduction in knee pain of ≥30% and ≥50% as assessed by the average pain WOMAC NRS 3.1 subscale score. Ranges 0-10 with 0 represents no pain and 10 represents extreme pain.

WOMAC NRS 3.1 Index Function WOMAC NRS 3.1 Index.. Improvement of function assessed of ≥30% and ≥50% as assessed by the average Function subscale score (knee) during the past 48 hours. Ranges Scoring 0-10, 0 is better or none and 10 is worse.

WOMAC NRS 3.1 Index Stiffness average subscale score. Ranges 0-10, 0 is better or none and 10 is extreme or worse.

WOMAC NRS 3.1 Index Overall average subscale score The WOMAC® NRS 3.1 Index consists of 24 questions and produces 3 sub-scales scores for pain (5 questions), stiffness (2 questions), and function (17 questions) and a total score that summarizes overall disability. Score of 0 is better and the higher score is worse

The PGIC is a self-administered question that rates participants overall improvement in chronic pain since beginning treatment from 1 "no change (or condition has worsened)" to 7 "a great deal better" in response to the question "Since beginning treatment, how would you describe the change (if any) in activity, limitation, symptoms, emotions, and overall QoL related to your arthritis".

The SF-36 v2 is a 36-item, patient-reported survey of patient health, consisting of 8 scaled scores, which are the weighted sums of the questions in their section. The 1-week recall form asks the respondent to answer the questions as they pertain to the way he or she felt or acted during the past week. Score ranges 0-100 higher scores indicate better health.

This WPAI questionnaire (WPAI:OA-knee) is a validated self-administered questionnaire that assesses work impairment due to OA . The questionnaire gathers information on employment status, hours worked, hours missed due to OA, and hours missed for any other reasons

Number of days rescue medication used or use of other pain medications and therapies

Data of SAE's, AE's, causally to IP, AE's of Special Interest (AEST), AE's requiring any intervention for index knee pain and AE's requiring pain medication.

MRIs will be reviewed by an independent trained reader blinded to participant characteristics, study information and timing of MRI scans. All measurement will be done in duplicate

MRIs will be reviewed by an independent trained reader blinded to participant characteristics, study information and timing of MRI scans. All measurement will be done in duplicate

MRIs will be reviewed by an independent trained reader blinded to participant characteristics, study information and timing of MRI scans. All measurement will be done in duplicate

MRIs will be reviewed by an independent trained reader blinded to participant characteristics, study information and timing of MRI scans. All measurement will be done in duplicate

X-Rays will be reviewed by an independent trained reader blinded to participant characteristics, study information and timing of MRI scans. All measurement will be done in duplicate

MRIs will be reviewed by an independent trained reader blinded to participant characteristics, study information and timing of MRI scans. All measurement will be done in duplicate

MRIs and x-rays will be reviewed by an independent trained reader blinded to participant characteristics, study information and timing of MRI scans and x-rays. All measurement will be done in duplicate.