Piclidenoson, an A3 adenosine receptor agonist, demonstrates clinical benefit in canine osteoarthritis: a pilot study

Objectives Treatments for canine osteoarthritis, a degenerative joint disease associated with impaired mobility and pain, which is common in older dogs, are limited. The objective of this clinical study was to investigate the efficacy and safety of piclidenoson (an agonist at the A3 adenosine receptor) for canine osteoarthritis. Methods Client-owned dogs with spontaneously developed osteoarthritis and a score ≥11 at baseline on the Liverpool Osteoarthritis in Dogs (LOAD) were randomized to PO piclidenoson at 100 or 500 μg/kg bid and followed for 90 days. The primary efficacy endpoint was change in LOAD score from baseline to Day 90. Results The safety population included 21 dogs (100 μg/kg bid, n = 10; 500 μg/kg bid, n = 11). The efficacy population included 19 dogs (2 had no post-baseline LOAD score). Baseline characteristics were similar in the 2 groups. The change in LOAD from baseline to Day 90 was significant in the 500 μg/kg bid group (LS-mean LOAD score of 25.4 [SE, 3.8] at baseline vs. 18.6 [SE, 3.8] at Day 90, p < 0.001), whereas in the 100 μg/kg bid dose, the change was significant at Day 30 and lost significance by Day 90 (LS-mean LOAD score of 26.5 [SE, 4.5] at baseline vs. 23.3 [SE, 3.8] at Day 90, p = 0.109). Change in pain, as reflected in the visual analog scale (VAS) was also significant in the 500 μg/kg bid group (LS-mean VAS of 5.1 [SE, 0.7] at baseline vs. 2.9 [SE, 0.7] at Day 90, p < 0.001). Lameness/pain, evaluated by the veterinarian, were also significantly reduced from baseline to Day 90 in the 500 μg/kg bid group ( p < 0.001). No serious adverse events deemed possibly- or probably-related to the study drug were reported. Clinical significance Piclidenoson was well tolerated, and the findings suggest potential efficacy, thus supporting its further evaluation as a treatment for canine osteoarthritis.