Effects of pentosan polysulfate in osteoarthritis of the knee: A randomized, double-blind, placebo-controlled pilot study

Ghosh P, Edelman J, March L, et al. · Current Therapeutic Research, Clinical and Experimental

Three of seven direct clinical assessments separated from control: duration of early-morning joint stiffness at weeks 4 to 16, pain at rest from week 8 onward, and patient global assessment at every timepoint after the fourth injection. Pain at rest was measured only in the 36 patients whose baseline score reached 2 cm, and the difference was a 0.5 cm reduction on a 10 cm scale. Pain on walking showed no significant difference at any timepoint on the absolute scale, and separated only on the proportion improving by 2 cm or more, 35.2-50.0% against 16.7-25.0%. Three of ten evaluable activities of daily living improved more than control, and the aggregated function score separated at weeks 8 and 12 (both P=0.02).

Population

Adults with knee osteoarthritis, mean age 63

Intervention

Sodium PPS 3 mg/kg IM weekly for 4 weeks

Comparator

Ringer's solution injection

Limitations

Attrition was heavy and uneven — 24 of 54 on PPS and 40 of 60 on control left the study, leaving 55.6% and 33.3% at 24 weeks, so the late timepoints rest on about thirty and twenty patients. Randomisation left the treated arm with shorter symptom duration, 5.0 against 6.8 years (P=0.03). Only the abstract asserts that pain on walking improved, and it names no measure: the results section reports no difference at any timepoint on the absolute scale, the discussion restates the finding as a frequency of response among patients scoring 2 cm or more, and the closing conclusion drops the claim. Part-sponsored by Arthropharm, which prepared both the drug and the control vials, with the article sponsored by bene-Arzneimittel. No independent confirmatory trial of the intramuscular regimen has followed.