Effects of pentosan polysulfate sodium on joint structure and function out to six months in naturally-occurring canine osteoarthritis

Stapledon CJM, Krishnan R, Peat RA, et al. · PLoS One

No between-group comparison on pain, gait or cartilage reached significance. Baseline pain was already unbalanced (Helsinki Chronic Pain Index 15.1 against 8.8, p=0.02); after adjustment the PPS group's score was 20.4% below baseline at week 26 against a 25.1% rise on placebo, with credible intervals that overlapped widely. Gait symmetry moved toward normal on PPS (change from baseline 9.3% against 2.8% at week 8, p=0.35; 11.5% against 3.0% at week 26, p=0.21). Total stifle cartilage volume changed -1.2% against -11.2% at week 8 (p=0.09) and +1.6% against -7.0% at week 26 (p=0.13). Of the serum markers only CTX-I (p=0.007) and hyaluronan (p=0.007) separated at week 26, and TIMP-1 did not. The paper reports effect sizes and says its interpretation was limited to descriptive statistics.

Population

20 client-owned dogs (21 enrolled) with radiographic stifle or elbow OA, aged 7–13, randomised 2:1 to PPS (14) or placebo (6); cartilage volume measured in the stifle dogs only (12 PPS, 5 placebo)

Intervention

PPS 3 mg/kg subcutaneous weekly for 6 weeks, followed 26 weeks

Comparator

Saline, owner-masked

Limitations

Sponsor-run, with four Paradigm employees or shareholders among the authors; no power calculation, unbalanced baseline pain, rescue medication in both arms, and no pain, gait or imaging comparison reaching significance. Canine OA is a model, not human evidence.