Simultaneous Monitoring of Monoclonal Antibody Variants by Strong Cation-Exchange Chromatography Hyphenated to Mass Spectrometry to Assess Quality Attributes of Rituximab-Based Biotherapeutics

Research of saccharides and related biocomplexes: A review with recent techniques and applications

Saccharides and biocompounds as saccharide (sugar) complexes have various roles and biological functions in living organisms due to modifications via nucleophilic substitution, polymerization, and complex formation reactions. Mostly, mono-, di-, oligo-, and polysaccharides are stabilized to inactive glycosides, which are formed in metabolic pathways. Natural saccharides are important in food and environmental monitoring. Glycosides with various functionalities are significant in clinical and medical research. Saccharides are often studied with the chromatographic methods of hydrophilic interaction liquid chromatography and anion exchange chromatograpy, but also with capillary electrophoresis and mass spectrometry with their on-line coupling systems. Sample preparation is important in the identification of saccharide compounds. The cases discussed here focus on bioscience, clinical, and food applications.

Supramolecular Mimotope Peptide Nanofibers Promote Antibody-Ligand Polyvalent and Instantaneous Recognition for Biopharmaceutical Analysis

Peptide-based supramolecules exhibit great potential in various fields due to their improved target recognition ability and versatile functions. However, they still suffer from numerous challenges for the biopharmaceutical analysis, including poor self-assembly ability, undesirable ligand-antibody binding rates, and formidable target binding barriers caused by ligand crowding. To tackle these issues, a "polyvalent recognition" strategy employing the CD20 mimotope peptide derivative NBD-FFVLR-GS-WPRWLEN (acting on the CDR domains of rituximab) was proposed to develop supramolecular nanofibers for target antibody recognition. These nanofibers exhibited rapid self-assembly within only 1 min and robust stability. Their binding affinity (179 nM) for rituximab surpassed that of the monomeric peptide (7 μM) by over 38-fold, highlighting that high ligand density and potential polyvalent recognition can efficiently overcome the target binding barriers of traditional supramolecules. Moreover, these nanofibers exhibited an amazing "instantaneous capture" rate (within 15 s), a high recovery (93 ± 3%), and good specificity for the target antibody. High-efficiency enrichment of rituximab was achieved from cell culture medium with good recovery and reproducibility. Intriguingly, these peptide nanofibers combined with bottom-up proteomics were successful in tracking the deamidation of asparagine 55 (from 10 to 16%) on the rituximab heavy chain after 21 day incubation in human serum. In summary, this study may open up an avenue for the development of versatile mimotope peptide supramolecules for biorecognition and bioanalysis of biopharmaceuticals.

Glycoproteomics of a Single Protein: Revealing Tens of Thousands of Myozyme Glycoforms by Hybrid HPLC-MS Approaches

Characterization of highly glycosylated biopharma-ceuticals by mass spectrometry is challenging because of the huge chemical space of coexistent glycoforms present. Here, we report the use of an array of HPLC-mass spectrometry-based approaches at different structural levels of released glycan, glycopeptide, and hitherto unexplored intact glycoforms to scrutinize the biopharmaceutical Myozyme, containing the highly complex lysosomal enzyme recombinant acid α-glucosidase. The intrinsic heterogeneity of recombinant acid α-glucosidase glycoforms was unraveled using a novel strong anion exchange HPLC-mass spectrometry approach involving a pH-gradient of volatile buffers to facilitate chromatographic separation of glycoforms based on their degree of sialylation, followed by the acquisition of native mass spectra in an Orbitrap mass spectrometer. Upon considering the structures of 60 different glycans attached to seven glycosylation sites in the intact protein, the large set of interdependent data acquired at different structural levels was integrated using a set of bioinformatic tools and allowed the annotation of intact glycoforms unraveling more than 1,000,000 putative intact glycoforms. Detectable isoforms also included several mannose-6-phosphate variants, which are essential for directing the drug toward its target, the lysosomes. Finally, for the first time, we sought to validate the intact glycoform annotations by integrating experimental data on the enzymatically dissected proteoforms, which reduced the number of glycoforms supported by experimental evidence to 42,104. The latter verification clearly revealed the strengths but also intrinsic limitations of this approach for fully characterizing such highly complex glycoproteins by mass spectrometry.

Current evidence of rituximab in the treatment of multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disorder of the central nervous system. The immunopathology of MS involves both T and B lymphocytes. Rituximab is one of the anti-CD20 monoclonal antibody therapies which deplete B-cells. Although some anti-CD20 therapies have been approved by the Food and Drug Administration for treatment of MS, rituximab is used off-label. Several studies have shown that rituximab has a good efficacy and safety in MS, including certain specific patient conditions such as treatment-naïve patients, treatment-switching patients, and the Asian population. However, there are still questions about the optimal dose and duration of rituximab in MS due to the different dosing regimens used in each study. Moreover, many biosimilars have become available at a lower cost with comparable physicochemical properties, pharmacokinetics, pharmacodynamics, efficacy, safety, and immunogenicity. Thus, rituximab may be considered as a potential therapeutic option for patients without access to standard treatment. This narrative review summarized the evidence of both original and biosimilars of rituximab in MS treatment including pharmacokinetics, pharmacodynamics, clinical efficacy, safety, and dosing regimen.

Online Collision-Induced Unfolding of Therapeutic Monoclonal Antibody Glyco-Variants through Direct Hyphenation of Cation Exchange Chromatography with Native Ion Mobility-Mass Spectrometry

Post-translational modifications (PTMs) not only substantially increase structural heterogeneity of proteins but can also alter the conformation or even biological functions. Monitoring of these PTMs is particularly important for therapeutic products, including monoclonal antibodies (mAbs), since their efficacy and safety may depend on the PTM profile. Innovative analytical strategies should be developed to map these PTMs as well as explore possible induced conformational changes. Cation-exchange chromatography (CEX) coupled with native mass spectrometry has already emerged as a valuable asset for the characterization of mAb charge variants. Nevertheless, questions regarding protein conformation cannot be explored using this approach. Thus, we have combined CEX separation with collision-induced unfolding (CIU) experiments to monitor the unfolding pattern of separated mAbs and thereby pick up subtle conformational differences without impairing the CEX resolution. Using this novel strategy, only four CEX-CIU runs had to be recorded for a complete CIU fingerprint either at the intact mAb level or after enzymatic digestion at the mAb subunit level. As a proof of concept, CEX-CIU was first used for an isobaric mAb mixture to highlight the possibility to acquire individual CIU fingerprints of CEX-separated species without compromising CEX separation performances. CEX-CIU was next successfully applied to conformational characterization of mAb glyco-variants, in order to derive glycoform-specific information on the gas-phase unfolding, and CIU patterns of Fc fragments, revealing increased resistance of sialylated glycoforms against gas-phase unfolding. Altogether, we demonstrated the possibilities and benefits of combining CEX with CIU for in-depth characterization of mAb glycoforms, paving the way for linking conformational changes and resistance to gas-phase unfolding charge variants.

Mass Spectrometry-Based Charge Heterogeneity Characterization of Therapeutic mAbs with Imaged Capillary Isoelectric Focusing and Ion-Exchange Chromatography as Separation Techniques

Imaged capillary isoelectric focusing (icIEF) and ion-exchange chromatography (IEX) are two essential techniques that are routinely used for charge variant analysis of therapeutic monoclonal antibodies (mAbs) during their development and in quality control. These two techniques that separate mAb charge variants based on different mechanisms and IEX have been developed as front-end separation techniques for online mass spectrometry (MS) detection, which is robust for intact protein identification. Recently, an innovative, coupled icIEF-MS technology has been constructed for protein charge variant analysis in our laboratory. In this study, icIEF-MS developed and strong cation exchange (SCX)-MS were optimized for charge heterogeneity characterization of a diverse of mAbs and their results were compared based on methodological validation. It was found that icIEF-MS outperformed SCX-MS in this study by demonstrating outstanding sensitivity, low carryover effect, accurate protein identification, and higher separation resolution although SCX-MS contributed to higher analysis throughput. Ultimately, integrating our novel icIEF-HRMS analysis with the more common SCX-MS can provide a promising and comprehensive strategy for accelerating the development of complex protein therapeutics.

Fractionation and online mass spectrometry based on imaged capillary isoelectric focusing (icIEF) for characterizing charge heterogeneity of therapeutic antibody

Imaged capillary isoelectric focusing (icIEF) technology has been proved to be robust for the characterization of protein charge heterogeneity due to its high-resolution pI discrimination and high-throughput. Although high performance liquid chromatography (HPLC) tandem mass spectrometry (MS) and offline fraction collection technologies including isoelectric focusing (IEF), ion exchange chromatography (IEX) and free flow electrophoresis (FFE) have been widely utilized for protein charge variant characterization, there are a few applications of MS coupling with icIEF as a front-separation technique and related fractionation technologies for protein charge heterogeneity. However, the application of icIEF-MS has been much less frequent due to difficulties in MS interface, compatible ampholyte and coated capillary cartridge designation, ultimately impeding the breadth of icIEF applications in protein charge heterogeneity. In this study, a therapeutic monoclonal antibody (mAb-M-AT) was used for its charge variant characterization on an integrated icIEF platform with functions including analytical profiling, MS online coupling and fraction collection for charge heterogeneities. The main protein component and its four charge variants were identified using direct icIEF-MS coupling. Additionally, the two major acidic and basic charge variants were collected using preparative fractionation after the protein focused in the separation capillary. The identity of the fractions was confirmed by LC-MS at intact protein level and the results were consistent with those using icIEF-MS online coupling. The multiple operation modes of the icIEF platform described above can be rapidly and flexibly switched just by changing customized capillary separation cartridges without drastically altering instrument configuration. The whole workflow of icIEF-based profiling, fractionation and MS online coupling for protein heterogeneity is straightforward, reliable, and accurate, thus providing comprehensive solutions for in-depth protein heterogeneity characterization.

The Non-Hodgkin Lymphoma Treatment and Side Effects: A Systematic Review and Meta-Analysis

OBJECTIVE

This paper aims to review studies regarding side effects found during Non-Hodgkin Lymphoma treatment, to suggest the drug class most associated with these effects, as well as the most prevalent side effect grade.

METHODS

This review is registered in PROSPERO (IDCRD42022295774) and followed the PICOS strategy and PRISMA guidelines. The search was carried out in the databases PubMed/MEDLINE, Scientific Electronic Library Online, and DOAJ. Medical Subject Headings Terms were used and quantitative studies with conclusive results regarding side effects during the non-Hodgkin lymphoma treatment were selected. Patent information was obtained from google patents.

RESULTS

Monoclonal antibodies were the main drug class associated with side effects during NHL therapy. The combination of Rituximab (Rituxan®; patent EP1616572B) and iInotuzumab (Besponsa®; patent EP1504035B3) was associated with a higher incidence of thrombocytopenia (p<0.05), while the combination of Rituximab and Venetoclax (Venclexta®; patent CN107089981A) was associated with a higher incidence of neutropenia (p<0.05) when compared to Bendamustine combinations (Treanda ™; patent US20130253025A1). Meta-analysis revealed a high prevalence of grade 3-4 neutropenia and thrombocytopenia in men. Finally, Americans and Canadians experienced a higher prevalence of these side effects, when compared to others nationalities (p<0.05).

CONCLUSION

Patents regarding the use of monoclonal antibodies in NHL treatment were published in the last year. Monoclonal antibodies associated with neutropenia (grade 3-4) and thrombocytopenia, especially in North American men treated for NHL, and with an average age of 62 years demonstrated importance in this study.

Multiattribute Monitoring of Charge-Based Heterogeneity of Recombinant Monoclonal Antibodies Using 2D HIC-WCX-MS

Charged heterogeneity of monoclonal antibody (mAb) products is regarded as a critical quality attribute (CQA) depending on its impact on the safety and efficacy profile of the product. Hence, manufacturers are expected to perform a comprehensive characterization of the charge heterogeneity to ensure that the manufactured product meets its specifications. Further, monitoring is also expected during the product lifecycle to demonstrate consistency in product quality. However, conventional analytical methods for characterization of hydrophobic and charge variants are nonvolatile salt-based and require manual fraction collection and desalting steps before analysis through mass spectrometry can be performed. In the present study, a workflow of a two-dimensional liquid chromatography method using mass spectrometry (MS)-compatible buffers coupled with native mass spectrometry was performed to characterize hydrophobic variants in the first dimension and charge variants in the second dimension without any need for manual fractionation. This novel two-dimensional (2D) hydrophobic interaction chromatography (HIC)-weak cation-exchange chromatography (WCX)-MS workflow identified 10 variants in mAb A, out of which 2 variants are exclusive to the 2D orthogonal method. Similarly, for mAb B, a total of 11 variants are identified, including 5 variants exclusive to the 2D orthogonal workflow. When compared to stand-alone, HIC resolved only 4 variants for both mAbs and WCX resolved 7 variants for mAb A and 6 variants for mAb B. In addition, the proposed method allows direct characterization of hydrophobic/charge variant peaks through native mass spectrometry in a single-run workflow.

Method Development and Qualification of pH-Based CEX UPLC Method for Monoclonal Antibodies

Post-translational modifications (“PTMs”) in monoclonal antibodies (mAbs) contribute to charge variant distribution, which will affect biological efficacy and safety. For the characterization of mAbs, charge variants are used as a critical quality attributes for product quality, stability consistency and effectiveness. Charge variants in mAbs are characterized by a time-consuming and a multistep process starting from cation/anion exchange chromatography, acidic/basic fractions collection and subsequent reverse phase (RP) liquid chromatography, coupled with mass spectrometry (MS) analysis. Hence, an alternative characterization approach that would be highly selective for ion exchange chromatography-based charge variant analysis, which is compatible with on-line MS detection, is needed in the biopharma industry. Against this backdrop, multiple studies are being conducted to develop a simple straight on-line charge variant analysis method. In this regard, we apply the current study, which aims to develop a charge variant analytical method, based on volatile buffers with low ionic strength that can be used for on-line MS detection of charge variants of mAbs. This would enable the detection on “PTMs” using low ionic strength mobile phase compatible with MS. Hence, fruitful data can be obtained with a single chromatography run without any test sample preparation, eliminating the need for multiple steps of analysis, time-consuming process and multiple sample preparation steps. Thus, Charge Variant Analysis-MS technique will allow the characterization of charge-related PTMs on the intact protein stage. In this regard, this study is about development of a method having combination of chromatography and volatile mobile phase for mass spectrometry detection of mAbs being analyzed in native form. The method is qualified considering pharmacopeia guidelines because the ultimate aim is to transfer this method for Quality Control (QC) release testing of a monoclonal antibody, which is critical for batch release and the regulatory point of view. Acidic and basic variants have been separated with high resolution peak profile. Furthermore, there was no matrix interference and good separation selectivity in terms of specificity was obtained using this method. The experimental data suggested for the linearity of the method are 2.4 mg/mL to 3.6 mg/mL with % RSD below 2.0%. Additionally, Limit of Quantitation is found to be 0.15 mg/mL, which is 5% of loading amount. Consistently, the data show that the method is precise under the same operating conditions with a short time interval. Overall a simple, accurate, robust and precise pH gradient cation exchange chromatography method was developed and qualified for the characterization of a therapeutic native mAb. Additionally, this method can be used to claim a biosimilar product profile of an in-house product compare to an innovator.