P283 Clinical predictors of switching biologic treatment in patients PsA: data from a single centre over 17 years

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Abstract Background Management of PsA has included biologic agents (bDMARDs) since the early 2000s, in addition to conventional disease-modifying antirheumatic drugs (csDMARDs). Switching of bDMARD treatment is currently common clinical practice in treatment failure. Our aims were to determine the most prescribed first line bDMARDs, reasons for switching and any clinical factors at baseline that may predict switching in PsA. Methods Data was analysed retrospectively from a cohort of 400 PsA patients followed through from 2002-2019. Statistical analysis was carried out (logistic regression, analysis of variance and descriptive statistics) using SPSS version 22. Results The median age at baseline was 38.4 years (interquartile range [IQR] 29.8 - 53.3 years), 52.5% were female. bDMARDs were started in 220 of the 400 patients (55.0%). Initial therapy was a TNFi in 212 patients (96.3%). The median age of those started on bDMARDs was 33.7 years (IQR 27.5 - 48.2 years), 52.5% were female. The most frequently prescribed was adalimumab (59.5%), followed by etanercept (33.2 %) and infliximab (3.2%). 106 out of the 220 patients (48.2%) were on at least one concomitant csDMARD. 83 patients (37.8%) switched to a second bDMARD; 69 of these (83.1%) switched to a second TNFi. The commonest reasons for switching were primary or secondary inefficacy (61.0%) and adverse events (33.7%). The median duration on the first bDMARD was 11.6 months (IQR 3.8 - 30.1 months). Of the 83 patients who commenced a second bDMARD, 45 (54.2%) switched to a third bDMARD. The median duration on the second bDMARD was 10.0 months (IQR 3.0 - 33.0 months). The main reasons for the second switch were primary or secondary inefficacy (44.4%), adverse events (42.2%) and a combination of the two (11.1%). Patients who switched onto a second bDMARD were more frequently female (57.8%), had longer disease duration (14.01 versus 13.2 years), higher pain scores (84.2 versus 66.0) and higher tender/swollen joint counts compared to non-switchers at baseline. Patients using csDMARDs at baseline were more often responsive to initial bDMARD treatment than those on bDMARD alone (63.2% response versus 45.1%), but this was not statistically significant (p value >0.05). There was no significant change in drug survival of the first bDMARD if the patient was concurrently taking csDMARDS. A high ESR at baseline was associated with increased risk of switching from a second bDMARD to a third (odds ratio 1.20, p = 0.036). Conclusion We found that females, those with longer disease duration, higher subjective elements to disease activity at baseline were more likely to switch from initial bDMARD therapy. A high baseline ESR was associated with switching onto a third line bDMARD. Interestingly, the concurrent use of csDMARDs had no significant effect on the drug survival or efficacy of bDMARD therapy. Disclosures M. Naja None. L. R. Santos None. M. Greenwood None. M. Castelino None.