Where the same reference monoclonal antibody had been used by different applicants, it was found that the data showed a comfortingly high degree of similarity for the relative abundance of components across the laboratories, where the same glycan analytical technique had been used.
The authors then moved on to an investigation of seven specific mAbs within the 21, where it was shown that the biosimilar profile did not overlap the innovator profile for the Man5 high mannose component. What they found was that in each case, despite the high mannose relative percentage being out of range, the PK values were all within the acceptance range. There was very little difference between samples in terms of PK value and range but the sample with the highest relative difference in high mannose glycans between innovator and biosimilar (5.9%) also had the highest PK value (although still within the acceptance criteria range).
Their conclusion from the study was that differences can be detected in high mannose glycan populations through analytical means but that these, up to a certain point, do not translate into differences in PK within a defined acceptance range.
Therefore, analytical data can be key in identifying possible differences between biosimilar and innovator but differences observed will not necessarily translate into clinical differences unless they pass a certain relative threshold, which will be dependent on the structural feature under consideration.