Samsung biosimilar comparable to etanercept for psoriatic arthritis outcomes at 1 year
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Key takeaways:
- SB4 and etanercept showed similar effectiveness in patients with psoriatic arthritis.
- Drug persistence was “slightly higher” for etanercept at 1 year, but “similar” at 2 years.
Patients with psoriatic arthritis demonstrated similar disease activity outcomes and drug persistence after long-term treatment with either etanercept or its biosimilar SB4, according to data published in Arthritis Care & Research.
“Real-world data focusing on SB4 in PsA is very limited,” Katarzyna Losiska, MD, of the division of rheumatology and immunology at University Hospital, in Krakow, Poland, and colleagues wrote. “To our knowledge there is no published data specifically comparing the originator ETN and biosimilar ETN SB4 in terms of drug effectiveness and survival in the context of PsA. Thus, there is an emerging, unmet need for such analyses, as also addressed in the latest 2022 GRAPPA guidelines.”
To compare the effectiveness and persistence of the biosimilar SB4 (Benepali, Samsung Bioepis) with the originator etanercept (Enbrel, Amgen) in PsA, Losiska and colleagues conducted a retrospective comparative database observational study. Participants included 1,138 patients with PsA from five medical centers in Norway between January 1999 and September 2021, of whom 644 received etanercept while 252 were treated with SB4. All were etanercept-naïve. In addition, 242 etanercept-treated patients made mandatory, non-medical switches from the originator to SB4.
The researchers assessed change from baseline in disease activity score in 28 joints with erythrocyte sedimentation rate (DAS28-ESR), with a predefined equivalence margin of ±0.6, as well as drug persistence using the Kaplan-Meier survival method. The primary analyses compared unmatched cohorts, while supportive analyses, adjusted for confounders using propensity score, examined matched cohorts.
At 1 year from baseline, unmatched analyses of DAS28 change demonstrated a mean 0.67-point difference (95% CI, 0.38-0.96) between groups treated with etanercept (n = 140) and SB4 (n = 132), in favor of etanercept, according to the researchers. However, in the analyses matched for propensity score, the difference in change from baseline — 0.09 (95% CI, –0.33-0.5) — fell within the predefined equivalence margin of ± 0.6.
Drug persistence at 1 year was “slightly higher” for etanercept (0.75; 95% CI, 0.71-0.78) vs. SB4 (0.58; 95%CI 0.51-0.63) in the unmatched analysis, the researchers wrote.
However, they added that the estimated persistence rates were “similar” after propensity score matching, at 0.55 (95% CI, 0.46-0.53) for etanercept and 0.6 (95% CI, 0.51-0.67) for SB4.
For the patients who switched to SB4, DAS28-ESR “remained stable” at a mean 2.5 at the time of the switch (95% CI, 2.3-2.7), 2.3 for the 52 weeks afterward (95% CI, 2.1-2.5) and 2.2 at 2 years (95% CI, 1.9-2.4), according to the researchers.
“Our real-world study provides evidence that disease outcomes for biosimilar ETN SB4 and reference ETN are equivalent in both naïve and mandatory switching PsA patients cohorts,” Losiska and colleagues wrote. “Effectiveness was maintained in PsA patients who underwent mandatory switch from ETN to SB4.
“However, drug persistence rates at the end of 2-year follow-up were lower for biosimilar ETN SB4 than for reference ETN which requires further research and evaluation,” they added. “The clinical implications of this study support the view that SB4 ETN biosimilar is as effective and safe as the reference ETN for treatment of PsA patients both naïve to ETN and for switching from the originator drug.”
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