Real-World Treatment Patterns and Healthcare Costs in Patients with Psoriatic Arthritis Treated with Ixekizumab: A...

To describe adherence, persistence, discontinuation, restarting, switching, dosing, and health care costs among patients with psoriatic arthritis (PsA) treated with ixekizumab (IXE).

MarketScan administrative claims databases were used to select adults (≥18 years) initiating IXE between January 1, 2016, and June 30, 2019, for this retrospective study (earliest IXE claim = index). Eligible patients had one or more PsA diagnoses during the 12 months preceding the index and had 12 months of follow-up time after the index. Adherence (measured by proportion of days covered [PDC]) persistence (<60-day gap), discontinuation (≥90-day gap), switching, and dosing patterns were reported. Health care costs were reported per patient per month (PPPM) during follow-up and were assessed after adjusting PsA treatment costs for discount rates reported by the Institute for Clinical and Economic Review (ICER).

A total of 496 patients met the selection criteria (mean age, 51.1 years; 50.4% female). Over the 12-month follow-up, 52.8% remained persistent, 38.7% discontinued, 13.5% had no other treatment, 4.6% restarted, and 20.6% switched to a new biologic/traditional synthetic disease-modifying antirheumatic drug. 70.6%of patients were identified as highly adherent (i.e. PDC > 0.80)to IXE prior to discontinuation. Dose values were consistent with prescribing information for patients with and without comorbid psoriasis. Although IXE costs ($5233 [SD = $2497]) accounted for 85.6% of PsA-related health care costs, only 3.5% of IXE costs were patient out-of-pocket expenses. Adjusting for the ICER discounts decreased all-cause and PsA-related costs by $2509 PPPM.

Results from this real-world analysis suggest that treatment patterns and costs among patients with PsA initiating IXE are consistent with prior literature for other biologics.