A cautionary note on biosimilars has been discussed in a recent review (DT Rubin et al. Gastroenterol & Hepatol 2016; 12: 741-51)
In the recently completed NOR-SWITCH study presented at the United European Gastroenterology Week 2016 meeting, “a total of 481 patients were recruited across 40 centers: all patients had been on stable treatment with the originator infliximab for at least 6 months…When looking specifically at IBD patients, disease worsening was noted in 21.2% of originator infliximab-treated patients and 36.5% of CT-P13-treated Crohn’s disease patients (n=155).” The 15% difference did not reach statistical significance, but is concerning. The authors state that “subtle postranslational modifications unique to the biosimilars may be sufficient to lead to antidrug antibody formation with associated loss of response. Also, it is noted that this study did not include endoscopic evaluation.
The authors note that therapeutic monitoring worked with biosimilar product using available infliximab assays.
My take: We still have a lot to learn. The preliminary message, until more studies are available, indicate that switching stable patients could increase risk of losing response.
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