Impact of Plan-Level Access Restrictions on Effectiveness of Biologics Among Patients with Rheumatoid or Psoriatic Arthritis

Background: Novel disease-modifying antirheumatic drugs (DMARDs) can slow disease progression among patients with rheumatoid arthritis (RA) and psoriatic arthritis (PsA); however, some health plans require prior authorization (PA) or step therapy for access to treatments.

Objectives: This retrospective study compared treatment effectiveness among RA and PsA patients with and without plan-level access restrictions to biologic DMARDs (bDMARDs) or targeted synthetic DMARDs (tsDMARDs). Medication adherence, a component of effectiveness, was also examined as a secondary outcome.

Methods: RA and PsA patients aged 18-64 years with one or more claims for subcutaneous bDMARDs between January 1, 2014 and December 31, 2015, with plan-level access data available, were identified within the IBM MarketScan claims database. The primary outcome was treatment effectiveness assessed during the 12 months following the first qualifying DMARD claim. Multivariate modeling examined the correlation between access restrictions and treatment effectiveness. Medication adherence during the 12-month follow-up period was also compared between patients with and without access restrictions.

Results: Among 3993 RA and 1713 PsA patients, 34.2 and 35.1%, respectively, had access restrictions, of whom 70.5 and 78.9%, respectively, had plans with step therapy. Compared with patients whose plans did not require step therapy, odds of treatment effectiveness were 19% lower (odds ratio [OR] 0.81, 95% CI: 0.67-0.98; p  = 0.033) for RA patients and 27% lower (OR 0.73, 95% CI: 0.55-0.98; p = 0.037) for PsA patients in plans with step therapy. Differences in effectiveness were driven by differences in medication adherence, the odds of which were 19% lower (OR 0.81, 95% CI 0.68-0.96; p = 0.014) among RA patients and 29% lower (OR 0.71, 95% CI: 0.54-0.94; p = 0.017) among PsA patients in plans with versus without step therapy.

Conclusions: Compared with patients in plans without access restrictions or with PA only, RA and PsA patients in insurance plans with step therapy had lower odds of treatment effectiveness, mainly due to lower odds of adhering to treatment, during the 12 months following subcutaneous bDMARD initiation.