Jonathan Kay, MD


July 03, 2013

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Etanercept Biosimilar

Hello. I am Dr. Jonathan Kay, Professor of Medicine and Director of Clinical Research in the Division of Rheumatology at the University of Massachusetts Medical School and University of Massachusetts Memorial Medical Center, both in Worcester, Massachusetts. Today I am speaking to you from the 2013 European League Against Rheumatism (EULAR) Congress here in Madrid, Spain. Thank you for joining me.

At the meeting today, there were several presentations about biosimilars. This is a very hot topic now in rheumatology because biosimilars of infliximab, rituximab, and even adalimumab are beginning to be studied. The presentations today included an abstract[1] about a PROBIOMED® etanercept biosimilar that was studied in Mexico. In this study, comparative efficacy was examined in 3 groups of patients.

In this study, the Disease Activity Score 28 (DAS28) declined similarly in all groups. Patients were treated with Infinitam® and methotrexate or Enbrel®, the innovator etanercept, and methotrexate; and a larger group was treated with Infinitam and methotrexate. This study suggests that efficacy is similar, but additional data are going to be necessary before one can determine that the drug is truly biosimilar to etanercept.

Rituximab Biosimilar

The next study[2] was presented by a group from Pfizer, who presented data about their rituximab biosimilar, PF-05280586. This is a rituximab biosimilar that shares an identical amino acid sequence to rituximab; it was compared in analytic chemical assays as well as assays in vitro and in cynomolgus monkeys to determine the toxicology as well as the similarity of effectiveness of the Pfizer biosimilar compared with European and American branded rituximab.

In this study, the drug was shown to have very similar complement-dependent cytotoxicity, antibody-dependent cell-mediated cytotoxicity, and other parameters. In cynomolgus monkeys, pharmacokinetic parameters were very similar as well. This drug is now in clinical trials being compared with both MabThera® and Rituxan® in patients mainly in the United States but also outside of the United States. It will be interesting to see the results of these clinical studies, but this drug looks very promising as a biosimilar rituximab.


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