Acceptable changes in quality for glycosylated biologicals

Biosimilars/Research | Posted 06/05/2011 post-comment0 Post your comment

Research carried out by Sandoz into three glycosylated protein biotechnology drugs currently on the market showed quality changes over the period studied. Since all three drugs remained on the market with unchanged labels, this would indicate that the changes were accepted by the health authorities [1].


This seems to be good news for biosimilars – which are trying to prove ‘similarity’. Since, if the originators themselves can have such variability then the biosimilars may not have to be as ‘similar’ as originally thought.

What are acceptable quality changes has been in debate since the first marketing approvals of biologicals. This issue is especially relevant when we talk about manufacturing processes, which can be affected by process improvements, scale changes or site transfers, to name just a few.

Health authorities are of the opinion that changes in quality attributes are only acceptable if they do not change the safety and efficacy. But this seems to be based more on a principle than on scientific fact.

The research studied three glycosylated recombinant therapeutic proteins; darbepoetin alfa (Aranesp), rituximab (Rituxan/Mabthera) and etanercept (Enbrel) which were available on the market between 2007 and 2010. The data showed examples of acceptable variations for products that have remained on the market with unchanged product labels.

The following series of three articles discuss the quality changes found in each of the three glycosylated protein biologicals studied.

Related articles

Etanercept and quality attributes changes

Quality attributes changes for rituximab

Changes in the quality attributes of darbepoetin alfa


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.

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