The samples prepared and analysed as part of the MAM monitoring phase II, Section 2.2, were analysed using the NPD function, using parameters detailed in Section 2.5. For all batches assayed, batch 3 exhibited a modified peak in all 3 replicate preparations. Supplementary Figure presents the modified peak detected in DP batch 3 (red trace) relative to the drug substance (blue trace). Upon further investigation of this peak by further MS/MS analysis and using the GLP-Fc fusion protein sequence, the modified peak was identified as a sample preparation artifact, corresponding to NQVSLTCLVK peptide containing non-carboxymethylated cysteine residue (-58.00 Da). The fragmentation spectra and the corresponding fragment coverage map for both species is presented in Supplementary Figure . Non-carboxymethylated peptide represents 9% compared to the carboxymethylated peptide NQVSLTCLVK. No additional or modified peaks were flagged between the 3 other batches and the DS.