DISCONTINUATION, RESTART, AND SWITCHING PATTERNS AMONG PSORIASIS PATIENTS TREATED WITH ADALIMUMAB, ETANERCEPT OR USTEKINUMAB: A UNITED STATES CLAIMS DATABASE ANALYSIS
Method: This retrospective, observational study used administrative claims from the Truven Health MarketScan® Research databases. Patients met the following: administration of ADA, ETA, or UST between 2/8/2010-1/31/2011 (index date), ≥12 months continuous enrollment prior to and following the index date, 18+ years of age, and a diagnosis of PsO (ICD-9-CM diagnosis code 696.1x) prior to or on the index date. Patients with other immunologic disorders at baseline, including psoriatic arthritis, were excluded. Discontinuation was defined as a ≥90-day therapy gap following the end of days’ supply on an ADA or ETA claim or a ≥168-day gap following the end of days’ supply on a UST claim. Kaplan-Meier survival curves were created due to variable follow-up time. Patients were followed until discontinuation, disenrollment, or study end (1/31/2012), with censoring at disenrollment or 1/31/2012. Adjusted analyses using propensity score weighting on baseline variables were performed separately for UST vs ADA and UST vs ETA. The discontinuation hazard ratio (HR) was estimated using weighted Cox proportional hazard models. Restart, switch, time to restart and time to switch (all before discontinuation) were also examined.
Result: After weighting, a total of 2933 ADA, 4011 ETA, and 583 UST patients were included (mean age was 48.9-49.9 years and 55.1-58.2% male). UST patients had lower discontinuation rates compared to ADA or ETA patients (UST vs ADA: 39% vs 53%, p<0.001; UST vs ETA: 39% vs 56%, p<0.001) and similar mean time to discontinuation (UST vs ADA: 228 vs 231 days, p=0.815; UST vs ETA 228 vs 237 days, p=0.354). Overall, PsO patients were significantly less likely to discontinue from UST compared to ADA or ETA (UST vs ADA HR=0.626, p<0.0001; UST vs ETA HR=0.586, p<0.0001). Treatment re-starts were less frequent among UST patients (UST vs ADA: 9% vs 18%, p<0.001; UST vs ETA: 9% vs 23%, p<0.001). Fewer UST patients switched (UST vs ADA: 14% vs 21%, p<0.001; UST vs ETA: 15% vs 22%, p<0.001). Mean time to re-start ranged from 187-250 days. Mean time to switch ranged from 334-340 days.
Conclusion: Discontinuation, re-start, and switch rates were lower among PsO patient receiving UST compared to those receiving ADA or ETA.