BACKGROUND: Persistence to biologic agents such as adalimumab is generally low. However, treatment patterns after discontinuation of treatment, specifically treatment restarts, remain to be thoroughly investigated among adalimumab users. With the anticipated introduction of adalimumab biosimilars in the U.S. and the potential change in treatment landscape in the future, real-world evidence on current treatment interruption patterns is important. SPONSORSHIP: This study was sponsored by Boehringer Ingelheim Pharmaceuticals.
OBJECTIVE: Describe treatment interruption patterns among adalimumab users in a commercially-insured U.S. managed care population.
METHODS: A descriptive cohort study was conducted using a large administrative claims U.S. database. Patients with ≥1 adalimumab prescription claim from 10/1/2011 to 09/31/2014 were included. The first adalimumab claim date was used to define the index date. Patients were required to have 12 months pre- and post-index date continuous health plan enrollment. Patients were excluded if they had an adalimumab prescription in the pre-index period, or did not have an ICD-9-CM diagnosis code of at least one of the indicated conditions for adalimumab. Treatment patterns were evaluated in the post-index period overall and by indication. Treatment discontinuation was defined as a ≥45 day continuous supply gap, restarts were identified when adalimumab was re-initiated after a ≥45 day gap, and switches were identified when another biologic was received post-discontinuation.
RESULTS: A total of 20,252 patients met the study criteria. Rheumatoid arthritis (RA; 37.6%) was most prevalent, followed by plaque psoriasis (PP; 21.1%), Crohn’s disease (CD; 15.8%), psoriatic arthritis (PA; 4.8%), and ankylosing spondylitis (AS; 4.3%). Approximately 58.0% of patients discontinued adalimumab treatment (range: 62.8% RA to 43.3% CD). Mean (SD) time to discontinuation was longest for patients with PA [132.5 (88.4) days] and shortest for patients with PP [119.9 (95.7) days]. Among patients who discontinued adalimumab, 30.2% switched to another biologic, 27.6% restarted adalimumab, and 39.0% neither switched nor restarted their treatment. Among patients with a restart, mean (SD) days between medication discontinuation and restart was 82.7 (51.3) days.
CONCLUSIONS: The 1-year treatment discontinuation rate for adalimumab treatment is high. A significant proportion of patients discontinuing adalimumab treatment either restart adalimumab treatment or switch to another biologic. Further research is needed to understand why patients on adalimumab interrupt, switch, or discontinue treatment altogether.
