Treatment patterns and health care costs among patients with psoriatic arthritis treated with biologic or targeted synthetic disease-modifying antirheumatic drugs

BACKGROUND: Biologic and targeted synthetic disease-modifying antirheumatic drug (tsDMARD) therapies are used in management of psoriatic arthritis (PsA). Although previous studies have demonstrated that rates of adherence, persistence, discontinuation, and switching, as welt as health care costs, are variable among treatments, limited published data exist on more recently approved therapies. OBJECTIVE: To describe adherence, persistence, discontinuation, reinitiation, switching, dosing patterns, and health care costs among PsA patients treated with biologics and tsDMARDs. METHODS: This was a real-world, retrospective administrative claims study. Adult PsA patients with at least 1 claim for an approved PsA biologic (adatimumab, certotizumab, etanercept, golimumab, infliximab, secukinumab, or ustekinumab) or tsDMARD (apremitast or tofacitinib) between January 1, 2015, and June 30, 2019, were selected from the IBM MarketScan administrative claims databases. The first claim for one of the study treatments determined the index date and drug cohort. Patients were required to be continuously enrolled in their health plans for 12 months before and after the index date and to have at least 1 claim with a diagnosis of PsA in the 12 months before or on the index date. Adherence (measured by proportion of days covered [PDC] and medication possession ratio [MPRJ), persistence (<60-day gap in treatment), discontinuation (>90-day gap), reinitiation of index drug, switching, and dosing patterns for each index drug were assessed during the 12-month follow-up period. Health care costs were reported per patient per month (PPPM) during the 12-month follow-up and assessed after adjusting PsA treatment costs by the Institute for Clinical and Economic Review discount factors to account for discounts and rebates not usually reflected in claims data and by adherence. RESULTS: Overall, 6,674 patients met the selection criteria. The top 3 index drugs were adalimumab (37%), apremilast (26%), and etanercept (18%). Over 12 months of follow-up, 31%-59% of patients remained persistent on the index drug, whereas 35%-56% discontinued, 13%-29% switched to a different biologic or tsDMARD, and 3%-15% reinitiated the index therapy, depending on the index drug. The mean PDC ranged from 0.51 to 0.69 during the 12-month follow-up and 0.80 to 0.93 during the follow-up period before discontinuation. Dose values were largely consistent with prescribing information, with the exception of secukinumab. Index drug costs PPPM ranged from 52,361 (apremilast) to 56,528 for ustekinumab after adjustment for discounts and adherence. CONCLUSIONS: Results from this real-world analysis suggest that there is substantial variability in persistence, discontinuation, adherence, reinitiating, and switching patterns among the different biologic and tsDMARD treatment options for PsA patients. In addition, this study provides real-world cost data for biologics and tsDMARDs among patients with PsA.