Drifts in ADCC-related quality attributes of Herceptin®: Impact on development of a trastuzumab biosimilar

Abstract

A biosimilar product needs to demonstrate biosimilarity to the originator reference product, and the quality profile of the latter should be monitored throughout the period of the biosimilar's development to match the quality attributes of the 2 products that relate to efficacy and safety. For the development of a biosimilar version of trastuzumab, the reference product, Herceptin®, was extensively characterized for the main physicochemical and biologic properties by standard or state-of-the-art analytical methods, using multiple lots expiring between March 2015 and December 2019. For lots with expiry dates up to July 2018, a high degree of consistency was observed for all the tested properties. However, among the lots expiring in August 2018 or later, a downward drift was observed in %afucose (G0+G1+G2). Furthermore, the upward drift of %high mannose (M5+M6) was observed in the lots with expiry dates from June 2019 to December 2019. As a result, the combination of %afucose and %high mannose showed 2 marked drifts in the lots with expiry dates from August 2018 to December 2019, which was supported by the similar trend of biologic data, such as FcγRIIIa binding and antibody-dependent cell-mediated cytotoxicity (ADCC) activity. Considering that ADCC is one of the clinically relevant mechanisms of action for trastuzumab, the levels of %afucose and %high mannose should be tightly monitored as critical quality attributes for biosimilar development of trastuzumab.

Keywords: ADCC; FcγRIIIa; Herceptin®; N-glycan; biosimilar; quality drift; trastuzumab.

Figure 1.

Trends of N-glycan attributes that are related to biologic activities by expiry date. Dotted line shows the min-max range of expiry date before August 2018, 1st drift and 2nd drift periods. Boxplot shows the interquartile range, median and outlier (◊). Statistical significance was assessed with one-way ANOVA (*P ≤ 0.05). (A) %Afucose, (B) %High-mannose, (C) %Afucose + %High-mannose and (D) %Galactosylation.

Figure 2.

Trends of charge variant by expiry date using icIEF. Dotted line shows the min-max range of expiry date before August 2018, 1st drift and 2nd drift periods. Boxplot shows the interquartile range, median and outlier (◊). (A) %Acidic peak area, (B) %Main peak area, (C) %Basic peak area, (D) Representative icIEF electropherogram of Herceptin® via expiry date.

Figure 3.

Results of non-reducing CE-SDS and SE-HPLC profile. Dotted line shows the min-max range of expiry date before August 2018, 1st drift and 2nd drift periods. Boxplot shows the interquartile range, median and outlier (◊). (A) Trend of %higher-molecular-weight (%HMW) using non-reducing SE-HPLC, (B) Representative chromatograms for SE-HPLC analysis, (C) Trend of %IgG using non-reducing CE-SDS and (D) Representative CE-SDS electropherogram.

Figure 4.

Representative N-glycan chromatograms of Herceptin® via expiry date. After August 2018, the level of afucosylated and galatosylated glycan deceased (red arrows) and after June 2019 the level of high-mannose increased (violet arrows).

Figure 5.

Trend of biologic activities of Herceptin®. Dotted line shows the min-max range of expiry date before August 2018, 1st drift and 2nd drift periods. Boxplot shows the interquartile range, median and outlier (◊). Statistical significance was assessed with one-way ANOVA (*P ≤ 0.05). (A) Relative ADCC activity of Herceptin® (n = 102), (B) Relative FcγRIIIa binding activity of Herceptin® (n = 98), (C) Relative anti-proliferation potency of Herceptin® (n = 102), (D) Relative HER2 binding activity of Herceptin® (n = 102).