Safety and therapeutic value of radiosynoviorthesis with yttrium-90: a Canadian single-centre experience

Background. Yttrium-90 (Y-90) is approved in several countries as a radiosynoviorthesis agent in the intra-articular treatment of synovitis, however, no such radiopharmaceuticals are approved in Canada. The aim of this Health Canada-approved study was to examine the safety and efficacy of Y-90 synovectomy among patients with refractory synovitis. Methods. We performed a subset analysis of a prospective, phase III, single-arm, pan-Canadian trial. Large and medium-sized joints of adults with refractory inflammatory mono- or oligo-arthritis and minimal cartilage/bone destruction who failed treatment with two intra-articular corticosteroid injections were eligible. Patient follow-up was at 3, 6 and 12 months. Outcome measures included joint tenderness, swelling, effusion, joint function and bone scans. Results. A total of 79 joints were included (90% knees). The underlying diagnosis included SpA (35.2% of patients), RA (26.8%), JIA (8.5%) and other (29.6%). Non-biologic DMARDs were concurrently used in 59.2% of patients and biologic/targeted synthetic DMARDs in 31%. Five adverse events occurred, including one serious radiation burn requiring surgery. All events were non-life-threatening and resolved. Significant improvements in joint tenderness, swelling and effusion were achieved at 3 months (P < 0.001), which were maintained until 12 months. During follow-up, 92.3% of joints did not show radiographic progression. Per the treating physician, clinically important improvement in joint function was observed in 90% of joints. Conclusion. Our results confirm the safety of Y-90 radiosynoviorthesis in refractory synovitis and provide preliminary evidence supporting its clinical efficacy with sustained benefit at 12 months, suggesting that it is a safe alternative to surgical synovectomy in such cases. This is the first such study in a Canadian cohort.

Automated summary

The study examined the safety and efficacy of Y-90 synovectomy in patients with refractory synovitis, showing sustained benefits at 12 months and providing preliminary evidence supporting its clinical efficacy. This research suggests that Y-90 radiosynoviorthesis is a safe alternative to surgical synovectomy in cases of refractory synovitis, marking the first study of its kind in a Canadian cohort.