The research analysed multiple commercial batches of the glycosylated recombinant therapeutic protein etanercept (Enbrel) which were available on the EU and US markets.

Glycan mapping and caution exchange chromatography were used in order to study the glycans and different acid/basic variants present in the molecule.

Results showed highly consistent quality attributes for batches expiring before the end of 2009. From 2010 onwards batches with a different quality profile appeared in parallel to the original version.

Major differences were found in the glycosylation profile and in the amount of basic variants present in the molecule. Variants containing N-glycan G2F decreased from 50% to 30% and C-terminal lysine increased from 15% to 30%.

This seems to be good news for biosimilars – which are trying to prove ‘similarity’. Since, if the originators themselves can show such variation in quality attributes, then biosimilars may find it easier to prove ‘similarity’ than may have been thought.

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Reference

1. Schiestl M, Stangler T, Torella C, Cepeljnik T, Toll H, Grau R. Acceptable changes in quality attributes of glycosylated biopharmaceuticals. Nat Biotechnol. 2011;29(4):310-2.