Reference Infliximab and CT-P13 Show Similar Physicochemical and Functional Stability

Between reference infliximab and biosimilar infliximab CT-P13 (Inflectra, Remsima), different recommendations exist for the clinical solutions. Recently, a research article, published in BioDrugs, assessed and compared the stability of the solutions prepared from the originator and the biosimilar using a set of characterization methods in line with International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use recommendations.

The investigators used reconstituted solutions of the reference and the biosimilar, and dilutions were stored in glass vials (10 mg and 2 mg per mL) or in polyolefin infusion bags (0.4 mg per mL), and were subsequently refrigerated between 2°C and 8°C for 2 weeks.

The distribution of particulates was studied over a range of 0.001—1.0 µm by dynamic light scattering (DLS). Oligomers were analyzed by native size-exclusion ultra-high–performance liquid chromatography with ultraviolet (UV) visible detection coupled to native mass spectrometry (MS); MS was also used to evaluate natural aggregates and the isoform profile, and DLS was also used to detect gross conformational changes by tracking the hydrodynamic radius.

The secondary structure of the proteins was studied by far UV circular dichroism, while the tertiary structure was assessed by intrinsic tryptophan fluorescence. Reverse-phase ultra-high-performance liquid chromatography with UV detection was used to analyze intact reference and biosimilar infliximab for quantification.

Functionality was evaluated through biological activity as measured by the extension of the immunological reaction of the infliximab agents with tumor necrosis factor by enzyme-linked immunosorbent assay.

The authors write that the stress applied to both the reference and biosimilar solutions showed similar levels of aggregate formation, structural variation, and chemical modification. Only 1 notable difference emerged: in freeze-thaw cycles, CT-P13 was slightly more robust.

CT-P13 and the reference showed identical far UV circular dichroism spectra, which did not change over time. No significant changes were found in tertiary structure, and no aggregate process was noted during the period of the study. No meaningful differences emerged in the hydrodynamic radius of the solutions over time, and the concentration of infliximab in both products remained constant.

The 2 products have different glycosylation patterns, so differences in the native MS profile were found, which was expected. No important modifications developed over time.

The product’s function was maintained over the 60-day test period, and it was similar in all solutions tested.

The authors concluded that there were high levels of similarity between the reference and the biosimilar, and that when prepared and stored as normally used in the hospital pharmacy, all solutions showed physiochemical and functional stability.

Reference

Hermosilla J, Sánchez-Martín R, Pérez-Robles R, et al. Comparative stability studies of different infliximab and biosimilar CT-P13 clinical solutions by combined use of physiochemical analytical techniques and enzyme-linked immunosorbent assay (ELISA). BioDrugs. 2019;33(2):193-205. doi: 10.1007/s40259-019-00342-9.