The FDA uses the term ‘comparability’ only when referring to changes in the manufacturing process for originator biologicals. The term ‘highly similar’ is used when referring to the comparison of an originator or reference product to a biosimilar. The methods and analytical tools used, however, in both cases are the same.

The need for ‘comparability’ studies became necessary due to the increased demand for biologicals in the 1990s. This made scale up of manufacturing processes necessary, often leading to changes in the process or even moving site.

There was therefore a need to evaluate these products pre- and post-manufacturing change, leading to the term ‘comparability’ for biologicals. Evidence of ‘comparability’ then leads to interchangeability of the products without the need for (in most cases) clinical trials.

In Europe the term ‘comparability’ was extended to products from different sponsors in 2003 and became the basis for the EMAs approach to regulatory approval of biosimilars, and is also being used for post-approval manufacturing changes to biosimilars in Europe and elsewhere.

In the US, although, as of March 2010, a legal pathway exists for the approval of biosimilars, practical guidance from the FDA is still anticipated, but one thing is for sure ‘comparability’ or ‘highly similar’ is certain to be part of this guidance.

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Reference

1. McCamish M, Woollett G. Worldwide experience with biosimilar development. mAbs. 2011;3(2):209-17. doi:10.4161/mabs.3.2.15005