Table 1.

Compilation of Middle-Up and Middle-Down Results of the Three Antibodies

Antibody	Subunit	SC [%]	SVP [%]	Mass Acc. [ppm]
Panitumumab	LC	92.1	100.0	0.6
	Fc/2 deglyc.	90.5	100.0	0.8
	Fd	87.2	97.9	0.6
Cetuximab	LC	92.5	100.0	0.7
	Fc/2	91.9	100.0	0.6
	Fd	87.0	96.2	0.8
	Fd deglyc.	92.9	100.0	—
Natalizumab	LC	89.2	98.1	0.7
	Fc/2 deglyc.	90.5	100.0	0.7
in-house→	Fd Seq. A	79.9	90.0	78.0
Wang et al. →	Fd Seq. B	90.4	100.0	0.8

Summary of all middle-down and middle-up results from the subunits of panitumumab (IgG2), cetuximab (IgG1) and natalizumab (IgG4). SVP was 100 % or near 100 % for the correct sequences. They were in parallel validated by middle-up analysis and confirmed by mass accuracy <1 ppm. In the case of cetuximab Fd, a glycan modification at residue 88 decreased SVP to 96 %, deglycosylation provided 100 % SVP. For natalizumab Fd, SVP and UHR-QTOF results clearly confirmed “sequence B” published by Wang et al. as the correct sequence. ²⁴