Objectives: To evaluate the clinical efficacy and safety in patients with refractory ankylosing spondylitis (AS) initiating 99Tc-MDP therapy and explore the mechanisms.
Methods: Refractory AS patients were enrolled in the clinical trial and received 99Tc-MDP treatments for 3 or 5 courses according to ASAS improvement. Efficacy and safety evaluations were conducted during the follow-up. 37 cytokines were quantified by Luminex at baseline and week 30. p-values<0.05 were considered statistically significant.
Results: 51 refractory AS patients were included, with 20 healthy people serving as the control group. The patients were in an active disease state (mean (SD) ASDAS 3.66 (0.83), BASDAI 4.53 (1.92)), 42(82.35%) patients had syndesmophytes. Their cytokines were significantly higher than that in the control group. After 3 courses of 99Tc-MDP treatment, 32 (62.75%) patients achieved ASAS20 improvement, 24 (47.06%) patients achieved a clinically significant improvement (ΔASDAS-CRP≥1.1). 27 patients entered the second stage to complete 5 courses of the treatment, all of whom achieved ASAS20 improvement, 18 (66.67%) patients achieved a clinically significant improvement. All clinical parameters including ASAS and ASDAS significantly improved as the treatment was continued. Cytokines also had significant down-regulation after the treatment, and the reductions had positive correlations with the improvements of disease activity. No serious adverse event was observed.
Conclusions: This investigation confirmed the remarkable efficacy of 99Tc-MDP in a large number of refractory AS patients, and highlighted the mechanism by dramatic regulation on cytokines. 99Tc-MDP was safe in clinical application.