Characterization of PEGylation sites in Neulasta and a biosimilar candidate with a combined fragmentation strategy in mass spectrometry analysis.

In the development of biosimilar products to Neulasta, it is essential to determine the intact molecular mass and confirm precise PEGylation sites. In this study, we applied a combination of techniques, including post-column addition of triethylamine in reversed-phase liquid chromatography-mass spectrometry (RPLC-MS) to determine the intact molecular mass, and in-source fragmentation (ISF) and higher-energy collision dissociation-tandem mass spectrometry (HCD-MS/MS) to identify the PEGylation site. Our results show that both the pegfilgrastim biosimilar candidate and Neulasta lots are mono-PEGylated at the N-terminal end. Furthermore, we show that the combined ISF and HCD-MS/MS method can be used for identifying the PEGylation sites in the diPEGylated variant of pegfilgrastim. The diPEGylated variant has modification sites at the N-terminal end and a lysine at position 35 in the protein sequence.

Impact of Excipient Extraction and Buffer Exchange on Recombinant Monoclonal Antibody Stability.

The foundation of a biosimilar manufacturer's regulatory filing is the demonstration of analytical and functional similarity between the biosimilar product and the pertinent originator product. The excipients in the formulation may interfere with characterization using typical analytical and functional techniques during this biosimilarity exercise. Consequently, the producers of biosimilar products resort to buffer exchange to isolate the biotherapeutic protein from the drug product formulation. However, the impact that this isolation has on the product stability is not completely known. This study aims to elucidate the extent to which mAb isolation via ultrafiltration-diafiltration-based buffer exchange impacts mAb stability. It has been demonstrated that repeated extraction cycles do result in significant changes in higher-order structure (red-shift of 5.0 nm in fluorescence maxima of buffer exchanged samples) of the mAb and also an increase in formation of basic variants from 19.1 to 26.7% and from 32.3 to 36.9% in extracted innovator and biosimilar Tmab samples, respectively. It was also observed that under certain conditions of tertiary structure disruptions, Tmab could be restabilized depending on formulation composition. Thus, mAb isolation through extraction with buffer exchange impacts the product stability. Based on the observations reported in this paper, we recommend that biosimilar manufacturers take into consideration these effects of excipients on protein stability when performing biosimilarity assessments.

Qualification of a LC-HRMS platform method for biosimilar development using NISTmab as a model.

Biosimilars are a cost-effective alternative to biopharmaceuticals, necessitating rigorous analytical methods for consistency and compliance. Liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) is a versatile tool for assessing key attributes, encompassing molecular mass, primary structure, and post-translational modifications (PTMs). Adhering to ICH Q2R1, we validated an LC-HRMS based peptide mapping method using NISTmab as a reference. The method validation parameters, covering system suitability, specificity, accuracy, precision, robustness, and carryover, were comprehensively assessed. The method effectively differentiated the NISTmab from similar counterparts as well as from artificially introduced spiked conditions. Notably, the accuracy of mass error for NISTmab specific complementarity determining region peptides was within a maximum of 2.42 parts per million (ppm) from theoretical and the highest percent relative standard deviation (%RSD) observed for precision was 0.000219 %. It demonstrates precision in sequence coverage and PTM detection, with a visual inspection of total ion chromatogram approach for variability assessment. The method maintains robustness when subjected to diverse storage conditions, encompassing variations in column temperature and mobile phase composition. Negligible carryover was noted during the carryover analysis. In summary, this method serves as a versatile platform for multiple biosimilar development by effectively characterizing and identifying monoclonal antibodies, ultimately ensuring product quality.

Analytical and Functional Similarity of the Biosimilar Candidate ABP 654 to Ustekinumab Reference Product.

BACKGROUND AND OBJECTIVE: ABP 654 is a proposed biosimilar to ustekinumab reference product (RP), a human immunoglobulin isotype class G subclass 1 kappa monoclonal antibody that acts as an antagonist of interleukin (IL)-23 and IL-12. Ustekinumab RP is indicated for the treatment of some forms of plaque psoriasis, active psoriatic arthritis, Crohn's disease, and ulcerative colitis. ABP 654 and ustekinumab RP utilize different expression systems, and the purpose of this study was to assess analytical similarity between ABP 654 and ustekinumab RP sourced from the United States (US) and the European Union (EU). METHODS: The analytical testing plan included general properties, primary structure, higher-order structure, product-related substances and impurities, particles and aggregates, biological activity, and thermal stability and degradation studies. RESULTS: ABP 654 was found to be analytically similar to ustekinumab RP with respect to physicochemical and biological properties, including structure, function, purity, and potency. CONCLUSIONS: Based on a comprehensive similarity assessment, ABP 654 was found to be similar to ustekinumab RP, notwithstanding minor physicochemical differences that are not expected to have a clinically meaningful effect on safety or efficacy.

Recent advances in structural mass spectrometry methods in the context of biosimilarity assessment: from sequence heterogeneities to higher order structures.

Biotherapeutics and their biosimilar versions have been flourishing in the biopharmaceutical market for several years. Structural and functional characterization is needed to achieve analytical biosimilarity through the assessment of critical quality attributes as required by regulatory authorities. The role of analytical strategies, particularly mass spectrometry-based methods, is pivotal to gathering valuable information for the in-depth characterization of biotherapeutics and biosimilarity assessment. Structural mass spectrometry methods (native MS, HDX-MS, top-down MS, etc.) provide information ranging from primary sequence assessment to higher order structure evaluation. This review focuses on recent developments and applications in structural mass spectrometry for biotherapeutic and biosimilar characterization.

Comparison of middle- and bottom-up mass spectrometry in forced degradation studies of bevacizumab and infliximab.

Monoclonal antibodies (mAbs) used as therapeutics need comprehensive characterization for appropriate quality assurance. For analysis, cost-effective methods are of high importance, especially when it comes to biosimilar development which is based on extended physicochemical characterization. The use of forced degradation to study the occurrence of modifications for analysis is well established in drug development and may be used for the evaluation of critical quality attributes (CQAs). For mAb analysis different procedures of liquid chromatography hyphenated with mass spectrometry (LC-MS) analyses are commonly applied. In this study the middle-up approach is compared to the more expensive bottom-up analysis in a forced oxidation biosimilar comparability study. Bevacizumab and infliximab as well as biosimilar candidates for the two mAbs were forcefully oxidized by H2O2 for 24, 48 and 72 h. For bottom-up, the reduced and alkylated trypsin or Lys-C digested samples were analysed by LC-MS with quadrupole time-of-flight mass analyser (LC-QTOF-MS) to detect susceptible residues. By middle-up analysis several species of every subunit (Fc/2, light chain and Fd') were detected which differed in the number of oxidations. For the most abundant species, results from middle-up were in line with results from bottom-up analysis, confirming the strength of middle-up analysis. However, for less abundant species of some subunits, results differed between the two approaches. In both mAbs, the Fc was extensively oxidized. In infliximab, additional extensive oxidation was found in the Fab. Assignment to specific amino acid residues was finally possible using the results from bottom-up analyses. Interestingly, the C-terminal cysteine of the light chain was partially found triply oxidized in both mAbs. The comparison of susceptibility to oxidation showed high similarity between the reference products and their biosimilar candidates. It is suggested that the findings of middle-up experiments should be complemented by bottom-up analysis to confirm the assignments of the localization of modifications. Once the consistency of results has been established, middle-up analyses are sufficient in extended forced degradation biosimilar studies.

Demonstration of Physicochemical and Functional Similarity of Biosimilar Adalimumab-aqvh to Adalimumab.

BACKGROUND: Adalimumab-aqvh/CHS-1420 (YUSIMRYTM) (hereafter referred to as adalimumab-aqvh) was recently approved by the US Food and Drug Administration as a biosimilar for adalimumab. OBJECTIVE: The current study was conducted to investigate the analytical similarity of adalimumab-aqvh and the reference product, adalimumab. METHODS: The structural, functional, and stability attributes of adalimumab-aqvh and adalimumab were compared using state-of-the-art assays. The primary structure, disulfide structure, glycan profile, secondary and tertiary structures, molar mass, size variants, free thiol, charge variants, hydrophobic variants, post-translational modifications, subvisible particles, host cell proteins, and protein concentration were investigated. The functional similarity between adalimumab-aqvh and adalimumab was demonstrated by comparing fragment antigen-binding (Fab)-associated and fragment crystallizable (Fc)-associated biological activities. The stability of adalimumab-aqvh and of adalimumab was compared through forced degradation. RESULTS: The structural attributes of adalimumab-aqvh were identical to those of adalimumab or met the similarity criteria, with a few exceptions. Adalimumab-aqvh and adalimumab exhibited comparable stability profiles and functional activities. Any observed differences in the physiochemical attributes did not impact the conclusion of similarity because they did not influence any functional activities related to the adalimumab mechanism of action. CONCLUSION: The structural, functional, and stability data provide convincing evidence of biosimilarity between adalimumab-aqvh and the reference product, adalimumab.

In-Use Stability of SB12 (Eculizumab, Soliris Biosimilar) Diluted in Saline and Dextrose Infusion Solution after an Extended Storage Period.

INTRODUCTION: SB12 is a biosimilar to eculizumab reference product [SolirisTM (Soliris is a trademark of Alexion Pharmaceuticals, Inc.)] that acts as a C5 complement protein inhibitor. The infusion stability of in-use (diluted) SB12 outside the conditions stated in the reference product's label is unknown. OBJECTIVE: The objective of this study was to assess the stability of SB12 after extended storage in conditions not claimed in the originator label. METHODS: Infusion stability was assessed in SB12 samples (diluted in 0.9% NaCl, 0.45% NaCl, and 5% dextrose, final concentration of 5 mg/mL per clinical trial protocol and the reference product's label) kept at 5 ± 3 °C for up to 3 months, then 30 ± 2 °C/65 ± 5% relative humidity (RH) for 72 h. The product was stored in different containers [polyolefin (PO) bags, glass bottles and syringes], and the protocol followed International Conference on Harmonisation (ICH) and European Medicines Agency (EMA) requirements for stability evaluation of biological products. Stability was evaluated using complementary assays, including pH, protein concentration (A280), purity (size exclusion-high-performance liquid chromatography, capillary electrophoresis-sodium dodecyl sulfate, and imaged capillary isoelectric focusing), biological activity (C5 binding and inhibition), and safety (subvisible particles). RESULTS: Except for charge variants in SB12 diluted in 5% dextrose, all results met the stability acceptance criteria. There were no major changes in terms of physicochemical stability, biological activity, and subvisible particles. CONCLUSIONS: The infusion stability of SB12 after extended storage (5 ± 3 °C for up to 3 months, then 30 ± 2 °C/65 ± 5% RH for 72 h) was demonstrated for longer periods and at higher temperatures than what is stated in the EU and US labels of the reference product. The physicochemical properties, biological activity, and subvisible particles of in-use SB12 diluted in 0.9% NaCl and 0.45% NaCl were maintained under the described conditions and for all tested containers. However, instability was observed for the diluted SB12 in 5% dextrose. These results may reduce the workload of clinical staff and minimize drug waste from treatment delays without any loss in product quality and biological activity.

Post-translational modifications comparative identification and kinetic study of infliximab innovator and biosimilars in serum using capillary electrophoresis-tandem mass spectrometry.

Despite reports indicating the potential impact of post-translational modifications on the activity of a monoclonal antibody, their prediction or monitoring post-administration remains a challenge. In addition, with the expiration of patents concerning the early generation of mAbs, the production of biosimilars is constantly increasing. Structural differences of biosimilars compared to the innovator product are commonly evaluated for the formulated product in the context of biosimilarity assessment. However, estimating their structural outcome after administration is particularly difficult. Due to the complexity of in vivo studies, there is a need to develop analytical strategies to predict PTMs consequently to their administration and their impact on mAbs potency. Here, we identified and evaluated the modification kinetics of 4 asparagine deamidations and 2 aspartate isomerizations of infliximab innovator product (Remicade®) and two biosimilars (Inflectra® and Remsima®) in vitro using serum incubation at 37 °C. The methodology was based on a bottom-up approach with capillary electrophoresis hyphenated with mass spectrometry analysis for an unequivocal assignment of modified and unmodified forms. 2 asparagines demonstrated a gradual deamidation correlated with incubation time. The specific extraction efficiency was evaluated to determine possible changes in the antigen binding affinity of infliximab with the incubation. Results showed the possibility to achieve an additional aspect concerning biosimilarity assessment, oriented on the study of the structural stability after administration.

Cation exchange chromatography on a monodisperse 3 µm particle enables extensive analytical similarity assessment of biosimilars.

Biosimilarity assessment requires extensive characterization and comparability exercises to investigate product quality attributes of an originator product and its potential biosimilar(s) and to highlight any differences between them. Performing a thorough comparison allows a shortened approval path, which also eliminates lengthy and expensive clinical trials, ensuring comparable product quality and efficacy but at lower drug prices. The wide variety of analytical methods available for biosimilar assessment ranges from biological to analytical assays, each providing orthogonal information to fully characterize biosimilar candidates. Intact native mass spectrometry (MS) has been shown to be an excellent tool for detection and monitoring of important quality attributes such as N-glycosylation, deamidation, sequence truncation and higher order structures. When combined with efficient upfront separation methods, simplification of the proteoform heterogeneity and associated complexity prior to MS analysis can be achieved. Native mass spectrometry can provide robust and accurate results within short analysis times and requires minimal sample preparation. In this study we report the use of a monodisperse strong cation exchange chromatography phase hyphenated with Orbitrap mass spectrometry (SCX-MS) to compare the best-selling biopharmaceutical product Humira® with 7 commercially approved biosimilar products. SCX-MS analysis allowed for the identification of previously described as well as so far unreported proteoforms and their relative quantitation across all samples, revealing differences in N-glycosylation and lysine truncation, as well as unique features for some products such as sialylation and N-terminal clipping. SCX-MS analysis, powered by a highly efficient separation column, enabled deep and efficient analytical comparison of biosimilar products.

Multi-attribute method (MAM) to assess analytical comparability of adalimumab biosimilars.

Adalimumab drug product (Humira ®), the first fully human monoclonal antibody (mAb) approved by FDA in 2002, led the top ten list of best-selling mAbs in 2018 and has been the most profitable drug in the world. With the expiration of patent protection in Europe in 2018 and in United States by 2023, the landscape is changing as up to 10 adalimumab biosimilars are expected to enter the market in the US. Biosimilars offer the potential to lower costs on health care systems and increase patient accessibility. The analytical similarity of seven different adalimumab biosimilars was accomplished in the present study using the multi-attribute method (MAM), a LC-MS based peptide mapping technique that allows for primary sequence assessment and evaluation of multiple quality attributes including deamidation, oxidation, succinimide formation, N- and C- terminal composition and detailed N-glycosylation analysis. In the first step, characterization of the most relevant post-translational modifications of a reference product was attained during the discovery phase of MAM. During the second step, as part of the MAM targeted monitoring phase, adalimumab batch-to batch variability was evaluated to define statistical intervals for the establishment of similarity ranges. The third step describes biosimilarity evaluation of predefined quality attributes and new peak detection for the assessment of any new or modified peak compared to the reference product. This study highlights a new perspective of the MAM approach and its underlying power for biotherapeutic comparability exercises in addition to analytical characterization. MAM offers a streamlined comparability assessment workflow based on high-confidence quality attribute analysis using high-resolution accurate mass mass spectrometry (HRAM MS) and the capability to detect any new or modified peak compared to the reference product.

Demonstrating analytical similarity of a biosimilar HLX04 to bevacizumab with a panel of state-of-the-art methods and tiering of quality attributes.

Therapeutical monoclonal antibodies are structurally and functionally complex, whereas the innovator's manufacturing processes are proprietary. With respect to the similarity assessment, a proposed biosimilar product needs to demonstrate a side-by-side comparison between the reference product (RP) and candidate product in terms of physicochemical properties and biological activities, as well as nonclinical and clinical outcomes. Here, a comprehensive analytical similarity assessment was performed for in-depth comparison of HLX04, China-sourced Avastin® (CN-Avastin®), and Europe-sourced Avastin® (EU-Avastin®) following a tier-based quality attribute (QA) evaluation. A series of orthogonal and state-of-the-art analytical techniques were developed for the assessment. Ten lots of HLX04 were compared with 29 lots bevacizumab RP. Referred to the characterization results, HLX04 is highly similar to the RPs with respect to physicochemical properties and biological functions. In addition, HLX04 was found with similar stability and degradation behaviors upon multiple stressed conditions to bevacizumab. Minor differences were observed in glycosylation, aggregates, FcγRIIIa(F), and FcγRIIIa(V) binding activities; nevertheless, they were evaluated and demonstrated not to impact clinical outcomes. According to the reported clinical results, the totality of evidence, including the pharmacokinetic, efficacy, safety, and immunogenicity, further shows that HLX04 is similar to CN-/EU-Avastin®.

Trastuzumab Charge Variants: a Study on Physicochemical and Pharmacokinetic Properties.

Background: Post-translational modifications in bioprocessing and storage of recombinant mAbs are the main sources of charge variants. While the profile of these kinds of variants is considered an important attribute for the therapeutic mAbs, there is controversy about their direct role in safety and efficacy. In this study, the physicochemical and pharmacokinetic (PK) properties of the separated charge variants belonging to a trastuzumab potential biosimilar, were examined. Methods: The acidic peaks, basic peaks, and main variants of trastuzumab were separated and enriched by semi-preparative weak cation exchange. A panel of analytical techniques was utilized to characterize the physicochemical properties of these variants. The binding affinity to HER2 and FcγRs and the PK parameters were evaluated for each variant. Results: Based on the results, the charge variants of the proposed biosimilar had no significant influence on the examined efficacy and PK parameters. Conclusion: During the development and production of biosimilar monoclonal antibodies, evaluating the effect of their charge variants on efficacy and PK parameters is needed.

Characterization for the Similarity Assessment between Proposed Biosimilar SB12 and Eculizumab Reference Product Using a State-of-the-Art Analytical Method.

BACKGROUND: SB12 is being developed as a proposed biosimilar to eculizumab reference product (RP), a humanized monoclonal antibody (IgG2/4 kappa immunoglobulin) that binds to the human C5 complement protein. Binding to this protein inhibits complement-mediated intravascular hemolysis by blocking its cleavage into C5a and C5b. Eculizumab RP is indicated for the treatment of patients with paroxysmal nocturnal hemoglobinuria (PNH) to reduce hemolysis, atypical hemolytic uremic syndrome (aHUS) to inhibit complement-mediated thrombotic microangiopathy, generalized myasthenia gravis who are anti-acetylcholine receptor antibody-positive, and neuromyelitis optica spectrum disorder in adult patients who are anti-aquaporin-4 antibody-positive. OBJECTIVE: The objective of this study was to demonstrate structural, physicochemical, and biological similarity between eculizumab RP and SB12 using various state-of-the-art analytical methods. METHODS: Comprehensive analytical characterization was conducted with side-by-side comparison of SB12 with European Union (EU) and United States (US) eculizumab RPs using various analytical methods (more than 40 state-of-the-art assays). Comparisons included purity, product-related impurity, charge heterogeneity, primary structure, post-translational modification, higher-order structure, quantity, Fab-related biological activities (potency and binding activity), and Fc-related biological activities. RESULTS: Based on the analytical similarity assessment, the structural, physicochemical, and biological characterization results demonstrated that SB12 is highly similar to the EU and US eculizumab RP. In the structural aspects, it was confirmed that there is no difference between post-translational modification profiles and higher-order structures of SB12 compared with the eculizumab RP. Product-related impurities in the form of aggregates and charge variants were also confirmed to be similar. Mechanism of action (MoA)-related biological activities showed that SB12 is highly similar to the EU and US eculizumab RP with respect to overall critical and non-critical quality attributes analyzed. Moreover, similarity of comparative binding tendency of SB12 and eculizumab RP to Fc gamma receptors and C1q was confirmed through additional characterization methods. Based on these results, SB12 is expected to have highly similar safety and efficacy compared with eculizumab RP. CONCLUSION: In summary, the overall analytical characterization and similarity assessment results show that SB12 is highly similar to the EU and US eculizumab RP in terms of structural, physicochemical, biophysical, and biological attributes.

A rapid discriminative hydrogen-deuterium exchange and LC-HRMS/MS strategy for primary and higher order structural mapping of therapeutic proteins: a case study using filgrastim.

A vast number of therapeutic proteins are approved and available on the market. However, there are very limited analytical approaches available for the rapid determination of primary and higher-order structures which can be utilized for counterfeit identification. In the present study, filgrastim biosimilar products from different manufacturers were considered for developing discriminative orthogonal analytical techniques to determine structural variations. The developed intact mass analytical method and peptide mapping through LC-HRMS were able to differentiate three biosimilars based on deconvoluted mass and possible structural modification, respectively. Another structural attribute employed was charge heterogeneity through isoelectric focusing, which provides a snapshot of the presence of charge variants/impurities and was able to differentiate various marketed formulations of filgrastim. These three techniques can certainly differentiate the products that contain counterfeit drugs due to their capability concerning selectivity. Additionally, a unique HDX technique on LC-HRMS was developed, which can determine the labile hydrogen exposed to deuterium exchange in a specified time. HDX aids in identifying the workup process or changes in the host cell in the counterfeit product by differentiating the protein based on its higher-order structure.

Development of the Drug Product Formulation of the Bevacizumab Biosimilar PF-06439535 (Bevacizumab-bvzr).

BACKGROUND: PF-06439535 (bevacizumab-bvzr; Zirabev®) is a biosimilar of bevacizumab reference product (RP; Avastin®). This study describes the formulation development for PF-06439535. METHODS: PF-06439535 was formulated in several buffers and stored for 12 weeks at 40 °C to determine the optimal buffer and pH under stressed conditions. Subsequently, PF-06439535 at 100 and 25 mg/mL was formulated in a succinate buffer with sucrose, edetate disodium dihydrate (EDTA), and polysorbate 80, and in the RP formulation. Samples were stored at - 40 °C to 40 °C for ≤ 22 weeks. The physicochemical and biological properties relevant to the safety, efficacy, quality, or manufacturability were investigated. RESULTS: When stored at 40 °C for 13 days, PF-06439535 demonstrated optimal stability in histidine or succinate buffers and was more stable in the succinate formulation than the RP formulation, under both real-time and accelerated stability conditions. There were no significant changes in the quality attributes of 100 mg/mL PF-06439535 after storage at - 20 °C and - 40 °C for 22 weeks, and there were no changes in the quality attributes of 25 mg/mL PF-06439535 after storage at 5 °C (recommended storage temperature). Changes were observed at 25 °C for 22 weeks or at 40 °C for 8 weeks as expected. No new degraded species were observed in the biosimilar succinate formulation compared with the RP formulation. CONCLUSIONS: Results demonstrated that 20 mM succinate buffer (pH 5.5) is the PF-06439535 preferred formulation, and that sucrose is an effective cryoprotectant for processing and frozen storage, and an effective stabilizing excipient for 5 °C liquid storage of PF-06439535.

Taking the individual bias out of examining comparability of biosimilars: A case study on monoclonal antibody therapeutics.

Biosimilar manufacturers need to perform analytical and functional similarity assessments against the reference product. Successful demonstration allows for an abbreviated clinical path, thereby translating to affordable biosimilars. Current practices for regulatory concurrence on analytical similarity data are based on chart visualization and open to individual (human) bias. Here, we present a novel, chemometric approach for assessing biosimilarity that aims to simplify assessment and eliminate individual bias from decision making through application of weighted principal component analysis. Through the proposed approach, chemical information across the analytical characterization platform and drug products can be collated into a single plot for quantitative biosimilarity assessment. The proposed one-plot analysis offers a holistic visualization of 1) inter-product variability (w.r.t reference product) in cases where multiple batches per product have been investigated and 2) intra-product variability for each critical quality attribute (CQA) wherein information from orthogonal tools can be incorporated within the same plot. This allows for numerical grading of similarity for biosimilars of any given reference product. Although the proposed statistical approach is novel, it builds on standardized measures of CQA, criticality, and analytical procedures, thus making this approach easy to incorporate within the existing regulatory framework.

Development and validation of aggregates analysis method in analytical similarity assessment of HLX04 vs Avastin®.

Aggregate of therapeutic antibodies is usually considered as one of the most important critical quality attributes (CQA). The propensity of aggregates formation for bevacizumab is higher than other monoclonal antibody (mAb) drugs due to its tendency of self-association via the non-covalent interaction between the Fab arm of one bevacizumab molecule and the K445 residue on the heavy chain of another bevacizumab molecule. HLX04 has been developed as a biosimilar to bevacizumab (Avastin®) by Shanghai Henlius Biotech. To perform a head-to-head similarity evaluation with respect to aggregates or higher molecular weight species (HMWS) between HLX04 and Avastin®, we developed a robust high performance liquid chromatography (SEC-HPLC) method for aggregates analysis. Our characterization data indicated that HMWS of bevacizumab were mainly composed of dimers, and the dimer formation-dissociation equilibrium was influenced by protein concentration and storage temperature. Based on the characterization data of aggregates, we optimized the key parameters for SEC-HPLC based aggregates analysis method including mobile phase components and pH, autosampler temperature, as well as incubation conditions for sample pretreatment. The developed method was applied in HLX04 and Avastin® aggregates assessment and the similarity were confirmed among HLX04, China-sourced, and Europe-sourced Avastin® using both the pharmaceutical dosage forms and forced degradation samples. The method was also validated per ICH Q2 (R1) guidelines by challenging the parameters including specificity, accuracy, precision, linearity, range, limit of quantitation, and robustness. The validated method was applied in release test and stability study of HLX04 samples generated from commercial manufacturing process.

Modeling study of long-term stability of the monoclonal antibody infliximab and biosimilars using liquid-chromatography-tandem mass spectrometry and size-exclusion chromatography-multi-angle light scattering.

Monoclonal antibodies (mAbs) represent a dynamic class of biopharmaceutical products, as evidenced by an increasing number of market authorizations for mAb innovator and biosimilar products. Stability studies are commonly performed during product development, for instance, to exclude unstable molecules, optimize the formulation or determine the storage limit. Such studies are time-consuming, especially for mAbs, because of their structural complexity which requires multiple analytical techniques to achieve a detailed characterization. We report the implementation of a novel methodology based on the accelerated stability assessment program (ASAP) in order to model the long-term stability of mAbs in relation to different structural aspects. Stability studies of innovator infliximab and two different biosimilars were performed using forced degradation conditions alongside in-use administration conditions in order to investigate their similarity regarding stability. Thus, characterization of post-translational modifications was achieved using liquid-chromatography-tandem mass spectrometry (LC-MS/MS) analysis, and the formation of aggregates and free chain fragments was characterized using size-exclusion chromatography-multi-angle light scattering (SEC-MALS-UV/RI) analysis. Consequently, ASAP models were investigated with regard to free chain fragmentation of mAbs concomitantly with N57 deamidation, located in the hypervariable region. Comparison of ASAP models and the long-term stability data from samples stored in intravenous bags demonstrated a relevant correlation, indicating the stability of the mAbs. The developed methodology highlighted the particularities of ASAP modeling for mAbs and demonstrated the possibility to independently consider the different types of degradation pathways in order to provide accurate and appropriate prediction of the long-term stability of this type of biomolecule.

Mass spectrometry-based glycoprofiling of biopharmaceuticals by using an automated data processing tool: SimGlycan®.

The therapeutic and immunological properties of biopharmaceuticals are governed by the glycoforms contained in them. Thus, bioinformatics tools capable of performing comprehensive characterization of glycans are significantly important to the biopharma industry. The primary structural elucidation of glycans using mass spectrometry is tricky and tedious in terms of spectral interpretation. In this study, the biosimilars of a therapeutic monoclonal antibody and an Fc-fusion protein with moderate and heavy glycosylation, respectively, were employed as representative biopharmaceuticals for released glycan analysis using liquid chromatography-tandem mass spectrometry instead of conventional mass spectrometry-based analysis. SimGlycan® is a software with proven ability to process tandem MS data for released glycans could identify eight additional glycoforms in Fc-fusion protein biosimilar, which were not detected during mass spectrometry analysis of released glycans or glyco-peptide mapping of the same molecule. Thus, liquid chromatography-tandem mass spectrometry analysis of released glycans not only complements conventional liquid chromatography-mass spectrometry-based glycan profiling but can also identify additional glycan structures that may otherwise be omitted during conventional liquid chromatography-tandem mass spectrometry based analysis of mAbs. The mass spectrometry data processing tools, such as PMI Byos™, SimGlycan® , etc., can display pivotal analytical capabilities in automated liquid chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry-based glycan analysis workflows, especially for high-throughput structural characterization of glycoforms in biopharmaceuticals.