Treatment Persistence and Adherence Among Patients With Psoriatic Arthritis Who Initiated Targeted Immune Modulators in the US: A Retrospective Cohort Study

Introduction: This study compared treatment persistence and adherence among psoriatic arthritis (PsA) patients in the US who initiated an interleukin-12/23 inhibitor (IL-12/23i) versus those who initiated tumor necrosis factor inhibitors (TNFis), targeted synthetic disease-modifying antirheumatic drugs (tsDMARDs), or interleukin-17 inhibitors (IL-17is).

Methods: Adults diagnosed with PsA with ≥ 1 claim for a targeted immune modulator were selected from the IBM MarketScan^® Commercial and Medicare Supplemental databases (October 1, 2013-October 31, 2018). The date of the first claim was the index date. Patients had continuous health plan enrollment for ≥ 12 months pre-index and ≥ 12-month post-index period. Pairwise propensity score matching with nearest-neighbor technique was performed. Persistence duration, discontinuation rate, and the proportion of days covered (PDC) were evaluated in biologic/tsDMARD naïve patients who initiated TNFis, IL-17is, tsDMARDs, or IL-12/23i (reference group).

Results: There were 238 matched patient pairs for TNFi versus IL-12/23i, 238 pairs for tsDMARD versus IL-12/23i, and 189 pairs for IL-17is versus IL-12/23i. Duration of persistence was longer for the IL-12/23i cohort than for the TNFi (269 vs. 215 days, p < 0.001) or tsDMARD (269 vs. 213 days, p < 0.001) cohorts, but comparable between the IL-12/23i and IL-17i cohorts (267 vs. 246 days, p = 0.199). Fewer patients in the IL-12/23i cohort discontinued their index medication than in the TNFi (53.4% vs. 73.9%, p < 0.001) or tsDMARD (53.4% vs. 71.8%, p < 0.001) cohorts, but no significant difference was observed between the IL-12/23i and IL-17i cohorts (52.9% vs. 58.2%, p = 0.288). During the 12-month follow-up, adherence (i.e., PDC) was higher among those who initiated an IL-12/23i than among those who initiated TNFis (0.64 vs. 0.56, p = 0.004) or tsDMARDs (0.64 vs. 0.58, p = 0.027), but similar to those who initiated IL-17is (0.64 vs. 0.65, p = 0.589).

Conclusion: In this real-world study of PsA therapies with differing mechanisms of action, the IL-12/23i demonstrated longer persistence and higher adherence than either TNFis or tsDMARDs, and comparability to IL-17is.