Transitioning from originator etanercept to biosimilar etanercept (SB4) using a specifically designed communication strategy resulted in a slightly lower persistence rate and smaller decreases in disease activity in patients with inflammatory rheumatic disease, according to the results of a study published in Arthritis Rheumatology.
Lieke Tweehuysen, MD, of the Department of Rheumatology, Sint Maartenskliniek, Nijmegen, The Netherlands, and colleagues investigated the effects of nonmandatory transitioning from originator etanercept to SB4. The investigators compared drug survival by Cox regression analyses adjusting for age, gender, diagnosis, etanercept treatment duration, etanercept dose interval, conventional synthetic disease-modifying antirheumatic drugs, and C-reactive protein (CRP), using a robust variance estimator to account for repeated subjects. The investigators assessed adjusted difference in CRP, Disease Activity Score in 28 joints using CRP (DAS28-CRP), and Bath Ankylosing Spondylitis Disease Activity Index change over 6 months.
A total of 635 patients agreed to transition to SB4; 625 patients were enrolled in the study, including 433 with rheumatoid arthritis, 128 with psoriatic arthritis, and 64 with ankylosing spondylitis. The historical cohort included 600 patients treated with etanercept in 2014.
The crude 6-month persistence rates for SB4- and etanercept-treated patients were 90% and 92%, respectively. Compared with the historical cohort, the transition cohort had statistically significant higher relative risk for discontinuation (adjusted hazard ratio [HR], 1.57; 95% CI, 1.05-2.36) and smaller decreases in CRP (adjusted difference, 1.8; 95% CI, 0.3-3.2) and DAS28-CRP (adjusted difference, 0.15; 95% CI, 0.05-0.25) over 6 months.
Significantly more subjective health complaints were given as a reason for SB4 discontinuation, which the authors note is attributable to the nocebo effect. The acceptance rate of SB4 in the current study (99%) is higher than that achieved with etanercept biosimilar CT-P13 (88%) in a prior study. The persistence rates in the current study are also higher (90%) compared with those of CT-P13 (76%) at 6 months.
The authors suggest that the higher acceptance and persistence rates of SB4 could be attributed to the implementation of the structured communication strategy prior to the initiation of the transition to SB4. They also note that the different administration route of SB4 might be associated with a lower possibility of “groupthink effects.” However, they cannot conclude that the communication strategy itself had a direct effect on the acceptance and persistence rates of SB4 as they did not randomly assign patients who transitioned to SB4 to receive either participation in the structured communication strategy or sham education. The effects of the communication strategy should be further explored in a randomized controlled trial.
Tweehuysen L, Huiskes VJ, van den Bemt BJ, et al. Open-label non-mandatory transitioning from originator etanercept to biosimilar SB4: 6-month results from a controlled cohort study [published online April 2, 2018]. Arthritis Rheumatol. doi: 10.1002/art.40516