SAT0400 REAL-WORLD SWITCH RATES AMONG BIOLOGIC-NAIVE PSORIATIC ARTHRITIS PATIENTS INITIATING APREMILAST, TUMOR NECROSIS FACTOR INHIBITORS OR INTERLEUKIN INHIBITORS
Authors: David Kaplan, Brian Ung, Corey Pelletier, Chuka Udeze, Marc Tian
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Psoriatic arthritis (PsA), an inflammatory arthritis, manifests in joints and surrounding tendons and ligaments.<sup>1</sup> As PsA progresses, patients may switch from 1 therapy to another, discontinue medication or use agents in combination. Previous real-world studies have demonstrated that treatment persistence and adherence rates for biologic-naïve PsA patients initiating apremilast or biologics (ie, tumor necrosis factor [TNF] and interleukin [IL] inhibitors) are not different.<sup>2,3</sup> Treatment switching is common among PsA patients. <h3>Objectives</h3> This study compares the rate of treatment switching among adult patients initiating treatment with apremilast, TNF inhibitor or IL inhibitors. <h3>Methods</h3> Adult patients with PsA were identified if they newly initiated treatment with apremilast, a TNF inhibitor (adalimumab, certolizumab, etanercept, golimumab, infliximab) or an IL inhibitor (ixekizumab, secukinumab, ustekinumab) between January 1, 2015, and December 31, 2016, and had a minimum of 12 months pre-index and post-index continuous enrollment in the Truven Health (now IBM Watson) MarketScan® Commercial and Medicare Supplemental Database. Propensity score matching, based on available demographic and clinical characteristics, up to 1:2, was utilized between apremilast and biologic patients. Switch was defined as a claim for a new PsA treatment after initiation of the index medication. Days to switch was defined as the number of days between the index date and date of switch. Adherence was assessed utilizing the proportion of days covered (PDC). Outcomes were assessed every 3 months, up to 24 months. <i>T</i>-test, Wilcoxon rank-sum test and chi-squared test were used to evaluate differences between cohorts for continuous and categorical variables, as appropriate. <h3>Results</h3> 471 biologic-naive PsA patients initiating apremilast were matched to 890 biologic-naive PsA patients initiating biologics (TNF: n=804; IL: n=86). Patient characteristics were similar between the 3 cohorts (mean age: 50 years; Charlson Comorbidity Index: 0.58 [apremilast], 0.55 [TNF] and 0.56 [IL]). There was a greater proportion of females in the apremilast vs IL cohorts (55% vs 42%; <i>P</i>=0.0249) and a lower proportion of patients with prior PsA systemic treatment (59% vs 79%; <i>P</i>=0.0046). In the TNF cohort, 64% patients received adalimumab, 29% etanercept, 4% infliximab, 2% certolizumab and 1% golimumab. In the IL cohort, 78% of patients received ustekinumab, 21% secukinumab and 1% ixekizumab. At 12 months, significantly fewer patients initiating apremilast switched treatment compared with those initiating TNF inhibitors (15.5% vs 26.6%; <i>P</i>&lt;0.0001), while no significant differences were observed for apremilast vs IL patients (15.5% vs 14%; <i>P</i>=0.714). Similar switching trends were observed at 24 months for patients initiating apremilast vs TNF (25.0% vs 36.5%; <i>P</i>=0.0109) or those initiating apremilast vs IL (25.0% vs 26.7%; <i>P</i>=0.8465). Among those switching by 12 months, mean days to switch was similar between apremilast and TNF patients (199 vs 200 days; <i>P</i>=0.9759) and apremilast and IL patients (199 vs 227 days; <i>P</i>=0.3602). Patients initiating apremilast had a similar treatment adherence rate as patients initiating a TNF inhibitor (PDC: 0.81 vs 0.84; <i>P</i>=0.0749) and a higher treatment adherence rate than patients initiating an IL inhibitor (0.81 vs 0.76; <i>P</i>=0.0071). <h3>Conclusion</h3> Biologic-naive PsA patients initiating apremilast demonstrated lower switch rates vs biologic-naive PsA patients initiating TNF inhibitors in a large US administrative claims database. No difference in rates of switching was observed between apremilast and IL patients. <h3>Reference</h3> [1] Stankler L. Clin Exp Dermatol. 1981;6:303-6. 2. Wu JJ. Poster presented at: ISPOR 2018. 3. Curtis JR. Poster presented at: ISPOR Europe 2018. <h3>Disclosure of Interests</h3> David Kaplan Consultant for: Celgene Corporation, Speakers bureau: Celgene Corporation. Abbvie, Pfizer, Brian Ung Shareholder of: Celgene Corporation, Employee of: Celgene Corporation, Corey Pelletier Shareholder of: Celgene Corporation, Employee of: Celgene Corporation, Chuka Udeze Shareholder of: Celgene Corporation, Employee of: Celgene Corporation, Marc Tian Shareholder of: Celgene Corporation, Employee of: Celgene Corporation