Evaluation of analytical similarity between trastuzumab biosimilar CT-P6 and reference product using statistical analyses

Mitigating In-Column Artificial Modifications in High-Temperature LC-MS for Bottom-Up Proteomics and Quality Control of Protein Biopharmaceuticals

Elevating the column temperature is an effective strategy for improving the chromatographic separation of peptides. However, high temperatures induce artificial modifications that compromise the quality of the peptide analysis. Here, we present a novel high-temperature LC-MS method that retains the benefits of a high column temperature while significantly reducing peptide modification and degradation during reversed-phase liquid chromatography. Our approach leverages a short inline trap column maintained at a near-ambient temperature installed upstream of a separation column. The retentivity and dimensions of the trap column were optimized to shorten the residence time of peptides in the heated separation column without compromising the separation performance. This easy-to-implement approach increased peak capacity by 1.4-fold within a 110 min peptide mapping of trastuzumab and provided 10% more peptide identifications in exploratory LC-MS proteomic analyses compared with analyses conducted at 30 °C while maintaining the extent of modifications close to the background level. In the peptide mapping of biopharmaceuticals, where in-column modifications can falsely elevate the levels of some critical quality attributes, the method reduced temperature-related artifacts by 66% for N-terminal pyroGlu and 63% for oxidized Met compared to direct injection at 60 °C, thus improving reliability in quality control of protein drugs. Our findings represent a promising advancement in LC-MS methodology, providing researchers and industry professionals with a valuable tool for improving the chromatographic separation of peptides while significantly reducing the unwanted modifications.

Titer and charge-based heterogeneity multiattribute monitoring of mAbs in cell culture harvest using 2D ProA CEX MS

Robust monitoring of heterogeneity in biopharmaceutical development is crucial for producing safe and efficacious biotherapeutic products. Multiattribute monitoring (MAM) has emerged as an efficient tool for monitoring of mAb heterogeneities like deamidation, sialylation, glycosylation, and oxidation. Conventional biopharma analysis during mAb development relies on use of one-dimensional methods for monitoring titer and charge-based heterogeneity using non-volatile solvents without direct coupling with mass spectrometry (MS). This approach requires analysis of mAb harvest by ProA for titer estimation followed by separate cation exchange chromatography (CEX) analysis of the purified sample for estimating charge-based heterogeneity. This can take up to 60-90 min due to the required fraction collection and buffer exchange steps. In this work, a native two-dimensional liquid chromatography (2DLC) mass spectrometry method has been developed with Protein A chromatography in the first dimension for titer estimation and cation exchange chromatography (CEX) in the second dimension for charge variant analysis. The method uses volatile salts for both dimensions and enables easy coupling to MS. The proposed 2DLC method exhibits a charge variant profile that is similar to that observed via the traditional methods and takes only 15 min for mass identification of each variant. A total of six charge variants were separated by the CEX analysis after titer estimation, including linearity assessment from 5 μg to 160 μg of injected mAb sample. The proposed method successfully estimated charge variants for the mAb innovator and 4 of its biosimilars, showcasing its applicability for biosimilarity exercises. Hence, the 2D ProA CEX MS method allows direct titer and charge variant estimation of mAbs in a single workflow.

Isolation and characterization of rabies monoclonal antibody charge variants

Current postexposure prophylaxis of rabies includes vaccines, human rabies immunoglobulin (RIG), equine RIG, and recombinant monoclonal antibodies (mAb). In the manufacturing of rabies recombinant mAb, charge variants are the most common source of heterogeneity. Charge variants of rabies mAb were isolated by salt gradient cation exchange chromatography (CEX) to separate acidic and basic and main charge variants. Separated variants were further extensively characterized using orthogonal analytical techniques, which include secondary and tertiary structure determination by far and near ultraviolet circular dichroism spectroscopy. Charge and size heterogeneity were evaluated using CEX, isoelectric focusing (IEF), capillary-IEF, size exclusion chromatography, sodium dodecyl sulfate polyacrylamide gel electrophoresis, and western blotting. Antigen binding affinity was assessed by enzyme linked immuno-sorbent assay and rapid florescence foci inhibition test. Results from structural and physicochemical characterizations concluded that charge variants are formed due to posttranslational modification demonstrating that the charge heterogeneity, these charge variants did neither show any considerable physicochemical change nor affect its biological function. This study shows that charge variants are effective components of mAb and there is no need of deliberate removal, until biological functions of rabies mAb will get affected.

Basic regulatory science behind drug substance and drug product specifications of monoclonal antibodies and other protein therapeutics

In this review, we focus on providing basics and examples for each component of the protein therapeutic specifications to interested pharmacists and biopharmaceutical scientists with a goal to strengthen understanding in regulatory science and compliance. Pharmaceutical specifications comprise a list of important quality attributes for testing, references to use for test procedures, and appropriate acceptance criteria for the tests, and they are set up to ensure that when a drug product is administered to a patient, its intended therapeutic benefits and safety can be rendered appropriately. Conformance of drug substance or drug product to the specifications is achieved by testing an article according to the listed tests and analytical methods and obtaining test results that meet the acceptance criteria. Quality attributes are chosen to be tested based on their quality risk, and consideration should be given to the merit of the analytical methods which are associated with the acceptance criteria of the specifications. Acceptance criteria are set forth primarily based on efficacy and safety profiles, with an increasing attention noted for patient-centric specifications. Discussed in this work are related guidelines that support the biopharmaceutical specification setting, how to set the acceptance criteria, and examples of the quality attributes and the analytical methods from 60 articles and 23 pharmacopeial monographs. Outlooks are also explored on process analytical technologies and other orthogonal tools which are on-trend in biopharmaceutical characterization and quality control.

A Retrospective Analysis of the Potential Impact of Differences in Aggregates on Clinical Immunogenicity of Biosimilars and their Reference Products

Aggregates, in particular high molecular weight species (HMWs), have been linked to increased immunogenicity. The current understanding on the impact of HMWs is mainly based on in vitro and nonclinical studies and there are only limited data available associating differences in HMWs in marketed monoclonal antibodies (mAbs) to clinical outcomes. Biosimilars offer a unique opportunity to study the potential association between quality parameters and clinical outcomes. We performed a retrospective evaluation to investigate the association between HMW content and reported antidrug-antibody (ADA) incidence in 30 full-length biosimilar mAbs approved in the European Union and the United States. Information for HMW content and ADA incidence were collected from publicly available sources. Differences in HMW content between biosimilars and their reference products (RPs) ranged from -0.75 to 1.65% with slightly higher differences observed in antineoplastic products as compared with immunosuppressant products. The difference in the ADA incidence between the RP and the biosimilar for the programs studied ranged from -11.0 to 18.5%. No association was observed between differences in HMW content and reported ADA incidence, in neither phase I nor phase III studies. Our results show that the limited differences in the content of HMWs between marketed biosimilars and reference mAbs were not associated with differences in reported immunogenicity, determined as incidence of ADAs and neutralizing ADAs in comparative clinical studies.

Assessment of structural and functional similarity of biosimilar products: Bevacizumab as a case study

The antiangiogenic drug bevacizumab is a blockbuster therapeutic pharmaceutical product that is used to treat many different types of cancer including kidney, colon, rectum, lung, and breast cancer. As a result, multiple biosimilars have been approved across the various regulatory jurisdictions in India (>20 in number till date). The rapidly growing market and acceptance of biosimilars was the motivation to perform comparability study of bevacizumab biosimilars that are presently available in the Indian market. A comprehensive analytical and functional biosimilarity assessment has been performed to examine and compare innovator product of bevacizumab (Avastin-innovator product, Roche Products (India) Pvt Ltd) and six biosimilars that are being marketed in India (Abevmy from Mylan Pharmaceuticals Pvt Ltd, Bevazza from Lupin Ltd, Bryxta from Zydus Cadila, Krabeva from Biocon, Ivzumab from RPG Life Sciences Ltd, and Advamab from Alkem Laboratories Ltd). Physiochemical characterization of drug products was performed with respect to their primary structure (intact mass, reduced mass, peptide mapping by LC-MS), higher order structure (secondary structure by FTIR, Far-UV-CD, and tertiary structure by Near-UV-CD, intrinsic fluorescence spectroscopy), impurity profile (SE-HPLC, SEC-MALS, extrinsic fluorescence: size heterogenicity, degradation, stability; DLS: hydrodynamic radius; WCX-HPLC: charge variants analysis) and post-translational modifications by measuring reduced glycans through fluorescence dye analysis. Functional characterization was performed by SPR and cell proliferation assay. Further, chemometrics based quantitative evaluation of biosimilarity has been performed by combining the data obtained from analytical characterization platform. The analysis of the analytical, functional and chemometric results revealed significant levels of similarity, with biosimilar4 being the sole exception. Despite being within product specifications, Biosimilar4 displayed significant deviations with respect to critical quality attributes, including a lower proportion of monomer content, a larger percentage of basic charge variant species, and a lower proportion of aglycosylated glycoform.

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^®.

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.

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.

Characterization of outcomes of amino acid modifications using a combinatorial approach to reveal physical and structural perturbations: A case study using trastuzumab biosimilar

Biopharmaceuticals, such as monoclonal antibodies, are considered as life-saving drugs for autoimmune diseases, cancer and infectious diseases. However, biotherapeutics tend to undergo chemical degradation during various stages of manufacturing. The conditions of chemical degradation, along with the physical degradation pathways, have a direct influence on the overall stability, safety and efficacy of these therapeutics. While site-specific chemical changes have been well-explored and investigated using various analytical approaches, the resulting conformational and structural changes have not been much studied. Thus, we explored various biophysical techniques for assessing the influence of three representatives forced degradation conditions viz. oxidation, deamidation, and glycation, in a model therapeutic trastuzumab biosimilar. The site-specific modifications caused by these stress conditions were analysed using high resolution mass spectrometry. While their thermodynamic and conformational consequences were investigated by using differential scanning colorimetry (Nano-DSC), circular dichroism (CD) spectroscopy, analytical ultracentrifugation (AUC), and dynamic light scattering (DLS). The investigated stress conditions resulted in reduced thermodynamic stability of mAb, as confirmed using Nano-DSC. Secondary structure analysis performed with CD spectroscopy indicated detectable structural alterations in the beta sheets of stressed samples. DLS and SV-AUC studies demonstrated an enhanced level of aggregation and fragmentation in presence of all stress conditions. Thus, the biophysical analytical toolkits, when used simultaneously, could offer deeper insights into the subtle conformational changes that result from site-specific chemical modifications in mAbs. Hence, these analytical approaches may serve as significant additions to the battery of techniques used for forced degradation analysis of biopharmaceuticals.

Comparison of originator and biosimilar monoclonal antibodies using HRMS, Fc affinity chromatography, and 2D-HPLC

Due to the complex manufacturing process of therapeutic monoclonal antibodies, it is hardly possible to produce an identical copy of the original product (originator). Consequently, follow-on products (biosimilars) must demonstrate their efficacy being similar to the originator in terms of structure and function. During this process, a variety of analytical methods are required for this purpose. This study focuses on three particularly relevant analytical techniques: high-resolution mass spectrometry, fragment crystallisable (Fc) affinity chromatography, and two-dimensional peptide mapping. Each analytical method proved able to identify specific differences between originator and biosimilar. High-resolution mass spectrometry was used to characterize the glycan pattern. It was shown that a trastuzumab biosimilar did not have the G0:G0F sugar modification identified in the originator. The application of affinity chromatography to rituximab showed that originator and biosimilar interacted differently with the immobilized Fc receptor. Furthermore, 2D-HPLC peptide mapping demonstrated the influence of orthogonality of separation dimensions, leading to differentiation of a rituximab originator and biosimilar.

Analytical Similarity Assessment of Biosimilars: Global Regulatory Landscape, Recent Studies and Major Advancements in Orthogonal Platforms

Biopharmaceuticals are one of the fastest-growing sectors in the biotechnology industry. Within the umbrella of biopharmaceuticals, the biosimilar segment is expanding with currently over 200 approved biosimilars, globally. The key step towards achieving a successful biosimilar approval is to establish analytical and clinical biosimilarity with the innovator. The objective of an analytical biosimilarity study is to demonstrate a highly similar profile with respect to variations in critical quality attributes (CQAs) of the biosimilar product, and these variations must lie within the range set by the innovator. This comprises a detailed comparative structural and functional characterization using appropriate, validated analytical methods to fingerprint the molecule and helps reduce the economic burden towards regulatory requirement of extensive preclinical/clinical similarity data, thus making biotechnological drugs more affordable. In the last decade, biosimilar manufacturing and associated regulations have become more established, leading to numerous approvals. Biosimilarity assessment exercises conducted towards approval are also published more frequently in the public domain. Consequently, some technical advancements in analytical sciences have also percolated to applications in analytical biosimilarity assessment. Keeping this in mind, this review aims at providing a holistic view of progresses in biosimilar analysis and approval. In this review, we have summarized the major developments in the global regulatory landscape with respect to biosimilar approvals and also catalogued biosimilarity assessment studies for recombinant DNA products available in the public domain. We have also covered recent advancements in analytical methods, orthogonal techniques, and platforms for biosimilar characterization, since 2015. The review specifically aims to serve as a comprehensive catalog for published biosimilarity assessment studies with details on analytical platform used and critical quality attributes (CQAs) covered for multiple biotherapeutic products. Through this compilation, the emergent evolution of techniques with respect to each CQA has also been charted and discussed. Lastly, the information resource of published biosimilarity assessment studies, created during literature search is anticipated to serve as a helpful reference for biopharmaceutical scientists and biosimilar developers.

Exploring the limits of conventional small-scale CHO fed-batch for accelerated on demand monoclonal antibody production

In the field of therapeutic antibody production, diversification of fed-batch strategies is flourishing in response to the market demand. All manufacturing approaches tend to follow the generally accepted dogma of increasing titer since it directly increases manufacturing output. While titer is influenced by the biomass (expressed as IVCD), the culture time and the cell-specific productivity (q_P), we changed independently each of these parameters to tune our process strategy towards adapted solutions to individual manufacturing needs. To do so, we worked separately on the increase of the IVCD as high seeding fed-batch capacity. Yet, as intensified fed-batch may not always be possible due to limited facility operational mode, we also separately increased the q_P with the addition of specific media additives. Both strategies improved titer by 100% in 14 days relative to the standard fed-batch process with moderate and acceptable changes in product quality attributes. Since intensified fed-batch could rival the cell-specific productivity of a conventional fed-batch, we developed novel hybrid strategies to either allow for acceptable seeding densities without compromising productivity, or alternatively, to push the productivity the furthest in order to reduce timelines.

Coupling of Trastuzumab chromatographic profiling with machine learning tools: A complementary approach for biosimilarity and stability assessment

Biosimilar products present a growing opportunity to improve the global healthcare systems. The amount of accepted variability during the comparative assessments of biosimilar products introduces a significant challenge for both the biosimilar developers and the regulatory authorities. The aim of this study was to explore unsupervised machine learning tools as a mathematical aid for the interpretation and visualization of such comparability under control and stress conditions using data extracted from high throughput analytical techniques. For this purpose, a head-to-head analysis of the physicochemical characteristics of three Trastuzumab (TTZ) approved biosimilars and the originator product (Herceptin®) was performed. The studied quality attributes included the primary structure and identity by peptide mapping (PM) with reversed-phase chromatography-UV detection, size and charge profiles by stability-indicating size exclusion and cation exchange chromatography. Stress conditions involved pH and thermal stress. Principal component analysis (PCA) and two of the widely used cluster analysis tools, namely, K-means and Density-based Spatial Clustering of Applications with Noise (DBSCAN), were explored for clustering and feature representation of varied analytical datasets. It has been shown that the clustering patterns delineated by the used algorithms changed based on the included chromatographic profiles. The applied data analysis tools were found effective in revealing patterns of similarity and variability between i) intact and stressed as well as ii) originator and biosimilar samples.

Need for a risk-based control strategy for managing glycosylation profile for biosimilar products

INTRODUCTION

Monoclonal antibodies, though a popular class of therapeutics, are complex molecules that are manufactured using complex processes, making it nontrivial to maintain high level of batch-to-batch consistency in product quality. Glycosylation is a posttranslation modification that is widely considered a critical quality attribute (CQA) as its variations are known to impact the Fc effector functions of mAbs. With continuing rise of biosimilars, comparability of these products to the reference product with respect to glycosylation is a topic of immense interest.

AREAS COVERED

In this article, we focus on the various aspects related to this topic including criticality of the various glycosylated forms, as well as comparability of biosimilars with respect to glycosylation.

EXPERT OPINION

We propose that manufacturers should focus on those glycoforms that are present in larger amounts and are known to be critical with respect to the biotherapeutic's safety and efficacy. Such risk-based evaluation of glycoforms and their control would offer an optimal route to biosimilar manufacturers for a cost-effective approach toward product development without compromising on the safety and efficacy characteristics of the therapeutic. For mAbs lacking Fc effector function, devising stringent glycosylation control strategies can be bypassed, thereby simplifying process and product development.

Uncertainty of Size-Exclusion Chromatography Method in Quality Control of Bevacizumab Batches

In addition to the analytical challenges related to the size and complexity of biopharmaceutical drugs, the inherent variability that arises due to their manufacturing process requires monitoring throughout the production process to ensure the safety and efficacy of the finished product. In this step, validation data should demonstrate that the process is controlled and reproducible, whereas the manufacturing process must ensure the quality and consistency of the product. For this, the manufacturer sets specification limits according with regulatory guidance. In such a situation, the comparison of different batches is required in order to describe and analyze the variability between them. However, it is unclear how great the variability of the analytical method would be or that in producing the batches. The estimation of the β-expectation tolerance intervals based on the variance components to account for both between-batch and within-batch variability was proposed as a specification limit to control the heterogeneity between batches at the time of manufacture and to verify whether batches meet specification limits. At this point, the variance components were computed by the maximum likelihood method using a linear random model. For this, the protein content, expressed as a percentage of the actual concentration relative to the claim value, and the dimer content (expressed as percentage) were used as critical quality attributes (CQAs) in the monitoring and control process. We used real data from six bevacizumab commercial batches.

Long-term efficacy and safety of CT-P6 versus trastuzumab in patients with HER2-positive early breast cancer: final results from a randomized phase III trial

PURPOSE

Equivalent efficacy was demonstrated for the biosimilar CT-P6 and trastuzumab following neoadjuvant therapy for patients with human epidermal growth factor receptor-2 (HER2)-positive early breast cancer. Following adjuvant treatment, efficacy and safety were comparable between treatments. We report updated safety and efficacy data after up to 3 years' follow-up.

METHODS

Following neoadjuvant chemotherapy with CT-P6/trastuzumab, patients underwent surgery and continued receiving adjuvant CT-P6/trastuzumab. The primary endpoint (previously reported) was pathological complete response. Time-to-event analyses (disease-free survival [DFS], progression-free survival [PFS], and overall survival [OS]), study drug-related and cardiac adverse events, and immunogenicity were assessed during post-treatment follow-up.

RESULTS

Most patients entered the follow-up period (CT-P6: 259 [95.6%]; trastuzumab: 269 [96.8%]). After a median follow-up of 38.7 (CT-P6) and 39.6 (trastuzumab) months, medians were not reached for time-to-event parameters; estimated hazard ratios (HRs) and 3-year survival rates were similar between groups. Estimated HRs (95% confidence intervals) for CT-P6 versus trastuzumab were 1.23 (0.78-1.93) for DFS, 1.31 (0.86-2.01) for PFS, and 1.10 (0.57-2.13) for OS (intention-to-treat population). Safety findings were comparable between groups for the overall study and follow-up period, including study drug-related cardiac disorders (CT-P6: 22 [8.1%] patients; trastuzumab: 24 [8.6%] patients [overall]) and decreases in left ventricular ejection fraction. Immunogenicity was similar between groups.

CONCLUSION

The similarity of the time-to-event analyses between CT-P6 and trastuzumab supports the equivalence in terms of efficacy established for the primary endpoint. CT-P6 was well tolerated, with comparable safety and immunogenicity to trastuzumab. ClinicalTrials.gov: NCT02162667 (registered June 13, 2014).

Statistical Equivalence Testing of Higher-Order Protein Structures with Differential Hydrogen Exchange-Mass Spectrometry (HX-MS)

Hydrogen exchange-mass spectrometry (HX-MS) is widely recognized for its potential utility for establishing the equivalence of the higher-order structures of proteins, particularly in comparability and similarity contexts. However, recent progress in the statistical analysis of HX-MS data has instead placed an emphasis on significance testing to identify regions of proteins where there are significant differences in HX between two or more protein states. In the cases involving assessment of similarity or equivalence of the higher-order structure of different protein samples (e.g., biosimilars), significance testing of HX-MS data is unsuitable. To meet this need, we have adapted the univariate two one-sided test (TOST) equivalence testing method for HX-MS data. Equivalence acceptance criteria were determined using maximum deviations from randomized resampling of truly equivalent samples to define hybrid equivalence criteria (maximum deviation of true equivalents, MDTE). Application of the TOST-MDTE test on differential HX-MS measurements of wild-type and mutated maltose-binding proteins demonstrates that the equivalence testing method was fit-for-purpose. Three infliximab biosimilars (Remsima, Renflexis, and Inflectra) were found to be equivalent to their Remicade reference product based on differential HX-MS measurements, while 5% deglycosylated NIST mAb was not statistically equivalent to the unmodified NIST mAb reference.

Safety Evaluation of Initial CT-P6 Administration for 30 min during the Switch from Reference Trastuzumab in Maintenance Infusion: A Multicenter Observational Study

CT-P6 is a biosimilar of trastuzumab and is recommended to be administered for 30-90 min in subsequent maintenance infusions to prevent infusion-related reactions (IRRs). We administered CT-P6 for 30 min as the first injection and as an alternative to reference trastuzumab in the maintenance infusion and evaluated the safety of the administration. A total of 140 patients with breast or gastric cancer, who received a switch from tri-weekly reference trastuzumab to CT-P6 for 30 min in maintenance infusions, were retrospectively evaluated. Premedication was administered prior to an infusion of CT-P6 and a cytotoxic agent. However, premedication was not provided when CT-P6 was co-administered with pertuzumab or administered alone. The primary endpoint was the incidence of IRRs. The secondary endpoint was the incidence of diarrhea and skin toxicity. Ninety-five percent of the patients had breast cancer, and 44.3% had advance-stage cancer. The treatment included CT-P6 alone (17.9%) or with cytotoxic agents (23.6%), antihormonal drugs (25.7%), and pertuzumab (62.9%). Median administration time of trastuzumab at the switch was 13 administrations (range 2-140). Premedication was administered to 20.7% patients. One patient (0.7%) experienced grade 3 IRR. The frequency of diarrhea in the reference trastuzumab group and the CT-P6 group was 7.1 and 6.4%, respectively, and that of skin toxicity was 6.4 and 5.0%, respectively, without differences. In conclusion, we first demonstrated that an initial CT-P6 administration for 30 min during the switch from reference trastuzumab in maintenance infusion is an acceptable administration method.

Limitations of the quality range approach in analytical similarity assessment: Effect of mean shift and relative variability

Recently in 2019, the United States Food and Drug Administration (FDA) circulated a new draft guidance for comparative analytical assessment. They suggest the use of quality range (QR) methods. In this article, selection of the k value, and the effect of mean shifts and relative variability are evaluated. These are expressed as a ratio between the two standard deviations of the tested product and the reference product, σ_T/σ_R. In a second step, the two modified versions of the QR method proposed by Son et al. (2020) are also analysed under several scenarios, through simulation studies using real data from a biotechnology company and our own data for bevacizumab. Results indicate that k has a great impact on the probability of passing similarity tests. Pass rates higher than 90 % can be achieved for small relative variabilities (σ_T/σ_R ≤ 0.6) and large mean shifts (≈4%) by using k = 3. The situation is totally different for k = 2: the pass rate is higher than 90 % for scenarios with small (<0.5 %) or no differences between the means of the two products, but this percentage decreases by up to 50 % for σ_T/σ_R = 1. Effectiveness in detecting the various scenarios was quantified by calculating the probability curves of passing the similarity test, as a function of the two variables for each k value. Alternative methods present the same limitations but with different magnitude in comparison with QR, this being most pronounced in the plausibility-interval QR method.

Development of a robust bioassay of monoclonal antibodies and biosimilars against TNF-α by NF-κB-inducible lentiviral reporter gene

The tumor necrosis factor alpha (TNF-α)/nuclear factor-kappa B (NF-κB) signaling pathway plays a crucial role in the pathogenesis of inflammatory diseases. Several therapeutic monoclonal antibodies (mAbs) and biosimilars against TNF-α have been developed to treat patients who suffer from inflammatory diseases caused by disordered expression of TNF-α. Hence, quality control of biopharmaceuticals is crucial during research and development. The high-order structure of these complex molecules cannot be entirely identified by physiochemical attributes; however, they can be inferred by observing biological activities. Thus, we developed a U937-based bioassay to determine the biological activities of mAbs and biosimilars against TNF-α using a low-basal NF-κB-inducible lentiviral reporter gene. The reporter gene assay (RGA) can be induced with a high signal-to-noise ratio (SNR) in a short time by TNF-α. Validation of the RGA showed accuracy (% relative standard deviation [RSD] = 4.64%), linearity (r² = 0.9856), and precision (Interday RSD = 4.6%, between analysts RSD = 3.51%) as well as reasonable specificity and robustness. The measured potency values of a biosimilar to adalimumab were between 90% and 110%. Results showed our RGA is suitable for mAb quality control and lot release, and for evaluation of the biological activity similarity of the biosimilar.

Fractionated charge variants of biosimilars: A review of separation methods, structural and functional analysis

The similarity between originator and biosimilar monoclonal antibody candidates are rigorously assessed based on primary, secondary, tertiary, quaternary structures, and biological functions. Minor differences in such parameters may alter target-binding, potency, efficacy, or half-life of the molecule. The charge heterogeneity analysis is a prerequisite for all biotherapeutics. Monoclonal antibodies are prone to enzymatic or non-enzymatic structural modifications during or after the production processes, leading to the formation of fragments or aggregates, various glycoforms, oxidized, deamidated, and other degraded residues, reduced Fab region binding activity or altered FcR binding activity. Therefore, the charge variant profiles of the monoclonal antibodies must be regularly and thoroughly evaluated. Comparative structural and functional analysis of physically separated or fractioned charged variants of monoclonal antibodies has gained significant attention in the last few years. The fraction-based charge variant analysis has proved very useful for the biosimilar candidates comprising of unexpected charge isoforms. In this report, the key methods for the physical separation of monoclonal antibody charge variants, structural and functional analyses by liquid chromatography-mass spectrometry, and surface plasmon resonance techniques were reviewed.

Comparison of Strategies in Development and Manufacturing of Low Viscosity, Ultra-High Concentration Formulation for IgG1 Antibody

Monoclonal antibodies requiring higher doses for exerting therapeutic effect but having lower stability, are administered as dilute infusions, or as two (low concentration) injections both resulting in reduced patient compliance. Present research summarizes impact of manufacturing conditions on ultra-high concentration (≥150 mg/mL) IgG1 formulation, which can be administered as one subcutaneous injection. IgG1 was concentrated to ~200 mg/mL using tangential flow filtration (TFF). Alternatively, spray dried (SPD) and spray freeze dried (SFD) IgG1, was reconstituted in 30%v/v propylene glycol to form ultra-high concentration (~200 mg/mL) injectable formulation. Reconstituted, SPD and SFD IgG1 formulations, increased viscosity beyond an acceptable range for subcutaneous injections (<20 cP). Formulations developed by reconstitution of SPD IgG1, demonstrated increase in high and low molecular weight impurities, at accelerated and stressed conditions. Whereas, the stability data suggested reconstituted SFD IgG1 was comparable to control IgG1 formulation concentrated by TFF. Also, formulation of IgG1 diafiltered with proline using TFF, reduce viscosity from ~21.9 cP to ~11 cP at 25 °C and had better stability. Thus, conventional TFF technique stands to be one of the preferred methods for manufacturing of ultra-high concentration IgG1 formulations. Additionally, SFD could be an alternative method for long term storage of IgG1 in a dry powder state.

Clinical development of CT-P6 in HER2 positive breast cancer

Introduction: CT-P6 (trastuzumab-pkrb, Herzuma) is a trastuzumab biosimilar approved for use in HER2 positive breast cancer and HER2 positive gastric cancer. CT-P6 has been shown to exhibit similar safety and efficacy profiles to its reference product, trastuzumab. Preclinical and clinical studies have been performed to prove equivalence between CT-P6 and the trastuzumab originator. Areas Covered: In this review, we examine the evidence comparing CT-P6 with its reference product, trastuzumab. Both monoclonal antibodies function to target cells that overexpress HER2 on the cell surface. Preclinical pharmacologic modeling of CT-P6 shows a similar mechanism of action to trastuzumab, similar pharmacologic properties and a phase I trial in healthy volunteers showed similar pharmacokinetics. A multicenter phase III randomized clinical trial in patients with early breast cancer showed equivalent safety and efficacy between CT-P6 and trastuzumab. One-year follow-up of patients showed identical rates of cardiotoxicity. Expert Opinion: Preclinical and clinical studies showed CT-P6 pharmacologic profile, safety and efficacy are equivalent to trastuzumab. As such, it is a safe and effective alternative for use in patients with HER2 positive breast cancer and gastric cancer. Its implementation into clinical practice can potentially increase patient access and help financially alleviate overburdened health-care systems.

Validation of a Size-Exclusion Chromatography Method for Bevacizumab Quantitation in Pharmaceutical Preparations: Application in a Biosimilar Study

In May 2019, the Food and Drug Administration (FDA) proposed a quality range (QR) method for the comparative analytical assessment in biosimilar studies. In this process, several reference product lots are necessary, selected from a wide period of manufacturing dates with different shelf lives, to calculate the total variability expressed as the standard deviation of reference product lots. This one depends on the between-lots variation and analytic method uncertainty (i.e., within-lots variation). During this time, the analytical method must be in control and stable but with an appropriate accuracy and precision. In such a situation, various control charts were used to fix the method requirements and detect small changes in the process. The results indicate that the method is indeed in control and stable, but does not meet the requirements of the Analytical Target Profile (ATP) approach, independently of the established uncertainty range. However, it does satisfy the traditional approach for an uncertainty range of ±2%. The application of this new QR approach shows that the selection of reference lots has an impact on the estimated standard deviation of the reference product, and consequently on the QR, penalizing good test products. The contribution of the analytic method error is known and in-control through the validation process. However, the between-lots variation requires a higher attention and control by the manufacturer. All these aspects were analyzed, using simulation and real-data from various bevacizumab lots.

Shifting Paradigms Revisited: Biotechnology and the Pharmaceutical Sciences

In 2003, Crommelin et al. published an article titled: "Shifting paradigms: biopharmaceuticals versus low molecular weight drugs" (https://doi.org/10.1016/S0378-5173(03)00376-4). In the present commentary, 16 years later, we discuss pharmaceutically relevant aspects of the evolution of biologics since then. First, we discuss the increasing repertoire of biologics, in particular, the rapidly growing monoclonal antibody family and the advent of advanced therapy medicinal products. Next, we discuss trends in formulation and characterization as well as summarize our current insights into immunogenicity of biologics. We spend a separate section on new product(ion) paradigms for biologics, such as cell-free production systems, production of advanced therapy medicinal products, and downscaled production approaches. Furthermore, we share our views on issues related to reaching the patient, including routes and techniques of administration, alternative development models for affordable biologics, biosimilars, and handling of biologics. In the concluding section, we outline outstanding issues and make some suggestions for resolving those.

Report of the AAPS Guidance Forum on the FDA Draft Guidance for Industry: "Drug Products, Including Biological Products, that Contain Nanomaterials"

To guide developers of innovative and generic drug products that contain nanomaterials, the U.S. Food and Drug Administration issued the draft guidance for industry titled: "Drug Products, Including Biological Products, that Contain Nanomaterials" in December 2017. During the AAPS Guidance Forum on September 11, 2018, participants from industry, academia, and regulatory bodies discussed this draft guidance in an open setting. Two questions raised by the AAPS membership were discussed in more detail: what is the appropriate regulatory pathway for approval of drug products containing nanomaterials, and how to determine critical quality attributes (CQAs) for nanomaterials? During the meeting, clarification was provided on how the new FDA center-led guidance relates to older, specific nanomaterial class, or specific product-related guidances. The lively discussions concluded with some clear observations and recommendations: (I) Important lessons can be learned from how CQAs were determined for, e.g., biologics. (II) Publication of ongoing scientific discussions on strategies and studies determining CQAs of drug products containing nanomaterials will significantly strengthen the science base on this topic. Furthermore, (III) alignment on a global level on how to address new questions regarding nanomedicine development protocols will add to efficient development and approval of these much needed candidate nanomedicines (innovative and generic). Public meetings such as the AAPS Guidance Forum may serve as the place to have these discussions.

Prevalence and role of HER2 mutations in cancer

HER2 activating mutations act as oncogenic drivers in various cancer types. In the clinic, they can be identified by next generation sequencing (NGS) in either tumor biopsies or circulating cell-free DNA (cfDNA). Preclinical data indicate that HER2 "hot spot" mutations are constitutively active, have transforming capacity in vitro and in vivo and show variable sensitivity to anti-HER2 based therapies. Recent clinical trials also revealed activity of HER2-targeted drugs against a variety of tumors harboring HER2 mutations. Here, we review the prevalence and type of HER2 mutations identified in different human cancers, their biochemical and biological characterization, and their sensitivity to anti HER2-based therapies in both preclinical and clinical settings.