No differences reach statistical significance
On the basis of discontinuation rates per 100 person-years, etanercept and its biosimilars performed almost identically (37.10 vs. 37.02, respectively). Although the discontinuation rate per 100 person-years was lower on infliximab than a biosimilar of it (29.97 vs. 37.96), the difference was not statistically significant (P = .076).
For adalimumab, the discontinuation rate was also lower on the originator drug than a biosimilar of it (32.92 vs. 36.36), but, again, this difference was also insignificant (P = .56).
When the discontinuation data were evaluated on the basis of a Cox model involving a propensity weight overlap, the univariate and the multivariable analyses found that the biosimilars had similar risks for discontinuation. Univariate analysis revealed hazard ratios for discontinuation of the biosimilar relative to the originator were 0.98 (P = .783) for etanercept, 1.17 (P = .242) for infliximab, and 1.08 (P = .09) for adalimumab. In the multivariable model, adjusted HRs for discontinuation were about the same for each of the biosimilars relative to the originator: 0.98 (P = .807) for etanercept, 1.19 (P = .183) for infliximab, and 1.08 (P = .089) for adalimumab.
Relative to previously published direct comparisons, this real-world analysis and its duration of follow-up address the limitations of formal trials. In a 2020 BMJ meta-analysis of published data from 45 trials comparing biosimilar with originator drugs in patients with RA who had failed methotrexate, the authors found only “minor differences in harms and benefits,” but they cautioned that the analysis was “hampered by a lack of long-term direct comparisons.”
In an interview, Dr. Huizinga noted that a systematic review of adalimumab biosimilars that he led 2 years ago showed that they perform comparably with the originator biologics. This and other published studies have consistently shown “that there is no difference between biologics and originators.”
Dr. Lacaille disclosed financial relationships with Fresenius Kabi, Janssen, Organon, Pfizer, and Viatris. Dr. Huizinga disclosed financial relationships with Abbott, Ablynx, Biotest, Bioscience, Boehringer Ingelheim, Bristol-Myers Squibb, Crescendo Bioscience, Eli Lilly, Galapagos, Janssen, Merck, Novartis, MycoMed, Roche, Sanofi-Aventis, Takeda, and Zydus.