Retention rate of TNF inhibitors versus IL-17 inhibitors in ankylosing spondylitis patients with prior biologics experience.

backgroundFor patients with ankylosing spondylitis (AS) who experience inefficacy or adverse events with biologics, no recommendations exist regarding the preference for class cycling or switching as a second- or higher-line biologics. Previous studies on the drug retention of TNF and IL-17 inhibitors in AS patients with prior biologics exposure have limitations, including relatively short follow-up periods, exclusion of patients with extra-articular manifestations, and a primary focus on second-line treatment. This study aimed to compare the retention rates of TNF and IL-17 inhibitors in AS patients with prior biologics experience, over a relatively longer follow-up period in real clinical practice.

methodsA total of 148 AS cases receiving either a TNF or IL-17 inhibitor as a second- or higher-line biologic were retrospectively analyzed after propensity score matching. Patient characteristics at the time of cycling or switching and drug retention were compared between the two groups. Subgroup analyses were conducted based on the reasons for drug discontinuation. Cox regression analyses were used to identify the factors associated with drug discontinuation.

resultsThe median follow-up period was 31.4 months, and drug survival tended to be lower for IL-17 inhibitors than for TNF inhibitors in the Kaplan-Meier analysis (P = 0.134). The lower retention of IL-17 inhibitors was more pronounced when discontinuations unrelated to treatment failure were censored (P = 0.034) or when used for reasons other than psoriasis aggravation (P = 0.028). However, in multivariable Cox regression, the number of previous biologics (HR: 1.62, 95% CI: 1.17-2.23, P = 0.003) and BASDAI (HR: 1.3, 95% CI: 1.03-1.65, P = 0.030) were significantly associated with drug discontinuation, whereas the class of biologics did not reach statistical significance (HR: 2.11, 95% CI: 0.96-4.63, P = 0.064).

conclusionIn patients with AS who had prior experience with biologics, the drug retention of TNF inhibitors tended to be higher compared to IL-17 inhibitors in real-world clinical practice. However, the factors significantly associated with higher drug survival were a lower number of previously exposed biologics and a lower BASDAI.