Background/Purpose: Real-world biologic persistence in PsA patients is lower compared to persistence in clinical trials. A comprehensive description of patterns of inadequate response (IR) to treatment is lacking. Frequency and timing of IR to biologics in the 1st year of treatment among PsA patients is described in this study.

Methods: This retrospective observational study analyzed USA commercial claims data (IBM® MarketScan®) from 2012–2017. Eligible PsA patients were biologic naïve (no claims for ≥1 year), ≥18 years old, with continuous enrollment in the database in the 12-month baseline and follow-up periods. Diagnoses were based on International Classification of Diseases (ICD) 9/10 codes. Index date was the 1st claim for a biologic or apremilast (small molecule; Table). Persistence was defined as treatment with the index biologic with gaps of ≤90 days over 12 months. IR was defined as follows: 110% of the label-recommended dose for ≥30 days (above-label dosing), new biologic initiation within 90 days of discontinuing index biologic (switch), addition of a corticosteroid/immunosuppressant/biologic with ≥30 days of overlap (add-on treatment), and index biologic cessation ( >90 days with no treatment) (non-switch discontinuation). Patients were classified according to the first IR event experienced.

Results: A total of 7,236 patients met the inclusion criteria. Persistence at 12 months was 48%, and was higher in males (53%) vs females (44%). Seventy-one percent of patients experienced an IR event in follow-up; the most frequent events were non-switch discontinuation (30%), followed by above-label dosing (16%), biologic switch (14%) and add-on treatment (11%). Median time from treatment initiation to IR event was 4.0 months, and was shortest for add-on treatment (3.1 months) and longest for biologic switch (4.6 months). Among the 1,716 patients with ≥12 months of follow-up after non-switch discontinuation, 53% had no subsequent biologic in the following 12 months, 31% restarted the index biologic, and 16% started a new biologic. IR distribution was similar irrespective of comorbid psoriasis and most recent provider (rheumatologist/dermatologist/other). Females (n=4,036) were more likely to experience an IR event than males (n=3,200) (74% vs 66%). Median time to IR event in females was 3.9 months vs 4.4 months in males.

Conclusion: IR to first biologic treatment, comprised primarily of adalimumab and etanercept, is common in PsA. Female patients are more likely to experience an IR event and to experience an event sooner vs males. Index biologic discontinuation (for >90 days) is common, with half of discontinuers remaining without a biologic exposure for ≥1 year, while the remaining discontinuers appeared to be taking a biologic drug holiday before restarting or initiating a new biologic. These variable treatment patterns suggest a variety of factors (including IR and others) are driving biologic discontinuation. Analysis of patient-level factors, such as clinical response and treatment access, is necessary to better understand the drivers of IR and to improve real-world treatment persistence. 

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/inadequate-response-within-a-year-of-biologic-and-oral-synthetic-dmard-treatment-initiation-among-psoriatic-arthritis-patients-in-the-usa-real-world-setting/