Dose escalation with tumor necrosis factor (TNF)-blockers is poorly characterized in pharmacy benefit management (PBM) settings.
This retrospective study used integrated pharmacy and medical claims from the PBM Medco to characterize dose escalation among rheumatoid arthritis (RA) patients treated with etanercept and adalimumab. Data from adults with RA with pharmacy claims for etanercept or adalimumab between 1/1/2007 and 12/31/2009 and continuous enrollment for ≥ 6 months before and ≥ 12 months after first (index) pharmacy claim were analyzed. "New" patients had no claim for TNF-blocker in the 6 months prior to receipt of their index TNF-blocker; otherwise, they were classified as "continuing" patients. Endpoints included 12-month persistence and duration on index medication and dose escalation. Dose escalation (allowed per adalimumab label but not for etanercept) in patients' persistent ≥ 12 months was estimated using five methods: (1) average weekly dose ≥ 110% of recommended label dose; (2) average subsequent dose ≥ 130% of starting dose; (3) last dose ≥ 110% of starting dose; (4) ≥ 2 consecutive instances of dose ≥ 130% of starting dose; and (5) any instance where dose increase connoted an additional syringe/vial use.
Data from 1,260 patients on etanercept and 852 patients on adalimumab were analyzed; 45.3 and 45.9% of new patients on etanercept and adalimumab, respectively, and 60.5 and 60.8% of continuing patients had ≥ 12 months persistence on index medication. Across all five methods used to estimate dose escalation, patients receiving etanercept had significantly lower rates of dose escalation (P < 0.001) than patients receiving adalimumab. For new patients, rates of dose escalation were 0.4-1.2% for etanercept and 8.3-14.1% for adalimumab. For continuing patients, rates ranged from 1.1 to 2.9% for etanercept and 7.0-28.3% for adalimumab.
New and continuing patients from this PBM database on etanercept had significantly lower rates of dose escalation than patients on adalimumab.