Studies on switching and retention for adalimumab and etanercept biosimilars yielded positive data, according to abstracts presented at the EULAR 2020 Congress.
Although adalimumab and etanercept biosimilars have been approved in the United States, these have not yet been brought to market, owing to exclusivity challenges. However, European studies investigating real-world applications of these agents are well along, based on presentations at the EULAR 2020 Congress, the virtual meeting of the European League Against Rheumatism.
Switching From Originators
An Italian study at Padova University Hospital evaluated the rate of switching from originator versions of these drugs to biosimilars in patients with rheumatoid arthritis (RA), psoriatic arthritis (PSA), and axial spondyloarthritis (axSpA). Investigators also evaluated survival for patients who switched to biosimilars versus those who didn’t.1
The study enrolled 1208 patients, of whom 560 (46.3%) switched to biosimilars: etanercept (n = 391) or biosimilar adalimumab (n = 169). The mean disease duration was 16 years, and the mean duration of the biologic disease-modifying antirheumatic drug (bDMARD) was 96.3 months.
Investigators said factors associated with switching were longer disease duration, shorter duration of previous bDMARD treatments, and diagnosis. Patients with RA had an almost 3-fold higher likelihood of being switched to biosmilars compared with patients with PSA or axSPA, according to the study. Investigators said the difference between PSA and axSPA in this context was not significant.
A longer drug survival was observed in patients who switched versus those who continued with originator drugs (HR 1.38; 95% CI, 1.2-1.58); however, investigators concluded that switching from the reference biologic to the biosimilar “does not affect the survival of the treatment. Indeed, it provides sustained effectiveness particularly if undertaken in patients with stable disease activity.”
They said longer drug survival was associated with longer disease duration, longer mean duration of previous bDMARDs, and diagnosis.
Investigators also concluded that “patients with longer disease duration and longer bDMARD duration were most likely to be switched successfully to biosimilars.”
Safety and Retention
In a second switching study, also conducted in Italy, investigators sought to evaluate the safety and retention rate for patients switched from the originator etanercept to the biosimilar (SB4, Benepali).2
The study enrolled 220 patients with RA, PSA, and ankylosing spondylitis (AS), juvenile idiopathic arthritis (JIA), and other rheumatic diseases treated with originator etanercept for at least 6 months. Investigators collected data on adverse events, loss of efficacy, and persistence on treatment. The rate of retention, reason for discontinuation, and other management data were collected at 6, 12, and 18 months.
Investigators said the originator biologic was used in various dMARD treatment lines: first, 76.8%; second, 17.7%; third, 3.2 %; and fourth, 2.3%. At a median follow-up of 12.1 months, 50 patients (22.7%) presented with at least 1 nonserious adverse event, with 36 (16.4%) instances of disease re-activation, and 30 (13.6%) interruptions of SB4 treatment, mostly related to safety and efficacy.
They said the retention rates were 99.1% (210/212) at 6 months, 90.9% (150/165) at 12 months, and 81.5% (53/65) at 18 months, respectively.
Of the 30 interruptions in biosimilar treatment, 17 patients were switched back to the originator product; the remaining patients were given a different drug regimen. Investigators said age was the only significant predictor of interruption at 6 months.
Retention rates at 6, 12, and 18 months were not influenced by disease, bDMARD line, conventional synthetic DMARD combination, gender, disease duration or originator etanercept duration.
“Our real-life data confirm the safety profile of switching from ETN to SB4. In our patients, the data show a higher retention rate, when compared to other-real life registries data,” investigators wrote.