Measured signature peptide concentrations   Condition 992 mAb 1024 mAb Tot mAbs Degradation inference 1 C992 = C C1024 = C =2*C = at HC N-term and at C-term Identical degradation 2 C992 = C C1024 = C ¹ 2*C = at HC N-term ¹ C-term. Different degradation at C-term 3 C992 C1024 = C992+C1024 ¹ at HC N-term = at C-term, but the same on individual mAb at HC N-term and C-term. Different catabolism of one mAb 4 C992 C1024 ¹ C992+C1024 Different catabolism, ¹ at HC N-term ¹ at C-term

Table 13: The four possible situations that can be reported from the measurement of in-vivo samples with the multi-analyte method, with some potential implications described. C: concentration, C992 specific 992mAb concentration, C1024 specific 1024mAb concentration, HC heavy chain. Two values are considered as identical if the differences are within 20% of BIAS% (25% at LLOQ).