Physicochemical and functional assessments demonstrating analytical similarity between rituximab biosimilar HLX01 and the MabThera®

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.

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.

Overview of tumor immunotherapy based on approved drugs

Tumor immunotherapy has become a new hotspot for cancer treatment. Various immunotherapies, such as immune checkpoint inhibitors, oncolytic viruses (OVs), cytokines, and cancer vaccines, have been used to treat tumors. They operate through different mechanisms, along with certain toxicities and side effects. Understanding the mechanisms by which immunotherapy modulates the immune system is essential for improving the efficacy and managing these adverse effects. This article discusses various currently approved cancer immunotherapy mechanisms and related agents approved by the Food and Drug Administration, the European Medicines Agency, and the Medicines and Medical Devices Agency. We also review the latest progress in immune drugs approved by the National Medical Products Administration, including monoclonal antibodies, cytokines, OVs, and chimeric antigen receptor-T cell therapy, to help understand the clinical application of tumor immunotherapy.

The current status of the biosimilars landscape in China

Biosimilars have played a significant role in alleviating healthcare burdens and enhancing patient access to high-quality biologic-based pharmaceutical therapies. The World Health Organization (WHO), as well as various national governments and regulatory agencies, have established corresponding regulations and guidelines to encourage the development of biosimilars. China, as a populous nation with a substantial demand for biologic therapies, has made substantial investments in the research and development (R&D) of a number of biosimilars, making it the global leader in terms of the number of biosimilar varieties developed and the companies involved. This article summarizes the landscape of biosimilar R&D and registration in China, the development of regulatory science for biosimilars (including guidelines) in China, the challenges faced in biosimilar development in China, and a discussion of and suggestions for tailoring or even waiving comparative clinical efficacy studies.

Long-term outcomes with HLX01 (HanliKang®), a rituximab biosimilar, in previously untreated patients with diffuse large B-cell lymphoma: 5-year follow-up results of the phase 3 HLX01-NHL03 study

HLX01 (HanliKang®) is a rituximab biosimilar that showed bioequivalence to reference rituximab in untreated CD20-positive diffuse large B-cell lymphoma (DLBCL) in the phase 3 HLX01-NHL03 study. Here, we report the 5-year follow-up results from the open-label extension part. Patients were randomised to either rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) or HLX01 plus CHOP (H-CHOP) every 21 days for up to six cycles. The primary efficacy endpoint was overall survival (OS), and secondary efficacy endpoint was progression-free survival (PFS). Of the 407 patients enrolled in HLX01-NHL03, 316 patients (H-CHOP = 157; R-CHOP = 159) were included in the 5-year follow-up for a median duration of 65.1 (range, 2.2-76.5) months. 96.5% of the patients had an International Prognostic Index (IPI) of 1 or 2, and 17.7% had bone marrow involvement. The 5-year OS rates were 81.0% (95% CI: 74.9-87.5%) and 75.4% (95% CI: 68.9-82.6%)( HR: 0.75, 95% CI 0.47-1.20; p = 0.23) while 5-year PFS rates were 77.7% (95% CI: 71.4-84.6%) and 73.0% (95% CI: 66.3-80.3%) (HR: 0.84, 95% CI 0.54-1.30; p = 0.43) in the H-CHOP and R-CHOP groups, respectively. Treatment outcomes did not differ between groups regardless of IPI score and were consistent with the primary analysis. H-CHOP and R-CHOP provided no significant difference in 5-year OS or PFS in previously untreated patients with low or low-intermediate risk DLBCL.

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.

Factors associated with the uptake of biosimilars for breast cancer treatment from the perspectives of physicians and patients-Evidence from China

Objective: To investigate the factors associated with the treatment of breast cancer with biosimilars from the perspectives of physicians and patients, and to generate evidence for promoting the uptake of biosimilars. Methods: This study targeted trastuzumab and its indicated human epidermal growth factor receptor 2 (HER2) positive breast cancer and included female HER2 positive breast cancer patients under treatment of trastuzumab at a provincial oncology medical center in southern China from 1 January 2021, to 31 December 2021. The study extracted patients' demographic, socioeconomic and clinical information and the basic information of their attending physicians from the hospital information system. We performed a bivariate multiple logistic regression analysis of predictive factors of the use of trastuzumab biosimilar. Results: A total of 446 patients (aged ranging between 26 and 74, 51.4 ± 9.06) were included in the analysis, and 19.1% chose biosimilar trastuzumab. Older patients, patients enrolled in the urban and rural resident health insurance program compared with those enrolled in the urban employee health insurance program, patients who initiated treatment after January 2021 when biosimilar entered clinical use compared with those who initiated treatment before, patients with female attending physicians, younger attending physicians and with chief attending physicians compared with deputy chief attending physicians were more likely to adopt biosimilar trastuzumab for treatment (p < 05). Controlling the other factors unchanged, when the patient's attending physician was deputy chief physician, increasing 1 year age of the patient was associated with an increased probability of adopting biosimilar by .8% (dy/dx = .008, 95%CI: .002-.01, p = .01). When the patient was aged between 26 and 60, the probability of adopting biosimilar for the patient whose attending physician was a chief physician was higher than for those whose attending physician was a deputy chief physician, and the gap was the largest when the patient was at the age of 45 (dy/dx = .20, 95%CI: .13-.27, p < .01). Conclusion: The uptake rate of biosimilars is still low at its initial development stage in China. Educational policies and physicians making recommendations to the indicated patients at the initiation stage of treatment are helpful to avoid reduced willingness to switch to biosimilars due to non-clinical reasons. Patients with lower ability-to-pay will have better accessibility to biologic regimens through the uptake of biosimilars. Official guidelines and professional training are critical to enhancing physicians' willingness and confidence in adopting biosimilars.

Rituximab biosimilar HLX01 versus reference rituximab in the treatment of diffuse large B-cell lymphoma: Real-world clinical experience

INTRODUCTION

HLX01 is the first rituximab biosimilar produced in China and the first monoclonal antibody biosimilar marketed in China. The purpose of this study was to comprehensively evaluate whether HLX01 is clinically consistent with the original drug based on real-world data to provide evidence for the clinical substitution of biosimilars in China.

METHODS

A single-center retrospective study was conducted to select patients with diffuse large B-cell lymphoma who met the inclusion criteria and were treated with HLX01 or reference rituximab. Baseline characteristics, efficacy and safety results were recorded, and the corresponding statistical analysis was performed for various indicators.

RESULTS

Thirty-three patients diagnosed with diffuse large B-cell lymphoma were included and divided into two groups that received HLX01 or reference rituximab. The results showed no significant difference in the overall response rate (86.7% vs. 88.9%; p = 1.000) or complete response rate (46.7% vs. 55.6%; p = 0.889) between the two groups. Kaplan-Meier survival curves also showed no significant difference in time-to-event variables between the two groups (log-rank = 0.244). Safety was also comparable in both groups.

CONCLUSIONS

HLX01 is a suitable replacement for reference rituximab in the treatment of diffuse large B-cell lymphoma and is relatively inexpensive, thereby reducing the economic burden of patients. Nevertheless, the conclusion of this study still needs to be further validated by large-sample real-world data and explored for HLX01 in other indications, such as follicular lymphoma.

CLINICAL TRIAL REGISTRATION

Not applicable.

Efficacy and safety of HLX01 in patients with moderate-to-severe rheumatoid arthritis despite methotrexate therapy: a phase 3 study

Background

To evaluate the efficacy and safety of HLX01, a rituximab biosimilar, as combination therapy with methotrexate in Chinese patients with active rheumatoid arthritis who had inadequate responses to methotrexate.

Methods

In this double-blind, placebo-controlled phase 3 trial, biologic-naïve patients with moderate-to-severe active rheumatoid arthritis and inadequate responses to methotrexate were randomized 2:1 to receive 1000 mg HLX01 or placebo intravenously on days 1 and 15. On the first day of weeks 24 and 26, patients in both groups received 1000 mg HLX01 via intravenous infusion. The primary endpoint was the American College of Rheumatology (ACR) 20 response rate at week 24. Secondary endpoints including efficacy, safety, immunogenicity, pharmacokinetics and pharmacodynamics were assessed up to week 48.

Results

Between 28 May 2018 and 11 September 2020, 275 patients were randomized to the HLX01 group (n = 183) or the placebo group (n = 92). At week 24, the proportion of patients achieving ACR20 response was significantly greater in the HLX01 group compared with the placebo group in the intention-to-treat population (60.7% vs 35.9%; P < 0.001) and per-protocol set (60.3% vs 37.1%; P < 0.001). Most secondary efficacy endpoints favoured HLX01 when assessed at weeks 12, 24, 36 and 48. Incidences of treatment-emergent adverse events were similar between groups. Infusion-related reactions occurred more frequently following the initial two doses of HLX01 than the subsequent doses.

Conclusions

HLX01 plus methotrexate improved clinical outcomes compared with placebo in Chinese patients with rheumatoid arthritis who had inadequate responses to methotrexate. This treatment regimen was well tolerated, showing comparable safety profiles to placebo.

Trial registration

ClinicalTrials.gov, NCT03522415. Registered on 11 May 2018.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02821-x.

Elucidating chemical and disulfide heterogeneities in rituximab using reduced and non-reduced peptide mapping

Peptide mapping by liquid chromatography-mass spectrometry is the gold standard to characterize post-translational modifications and disulfide bonds. The structural integrity, heterogeneity, and quality of biotherapeutic proteins are evaluated via reduced and non-reduced peptide mapping methods. However, non-enzymatic artifacts are often induced during sample preparation when alkaline pH conditions are used. To minimize these artifacts, methods using various acidic pH conditions have been developed by multiple researchers. However, these may lead to missed and non-specific cleavages during the analysis. In this study, improved reduced and non-reduced peptide mapping method has been proposed to characterize endogenous chemical modifications and native disulfide bonds of monoclonal antibody -based products. Solubilization has been carried out at acidic pH conditions under high temperature, followed by the addition of tris (2-carboxyethyl) phosphine as a reducing agent and a low alkylating agent. It was observed that the non-enzymatic post-translational modifications and non-native disulfide scrambled peptides significantly reduced under trypsin plus Lys-C digestion conditions at acidic pH as compared to the traditional methods. The results demonstrate that the proposed peptide mapping method using trypsin plus Lys-C could identify and quantify various chemical and disulfide heterogeneities with minimal artifacts. This article is protected by copyright. All rights reserved.

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.

Safety Profile of Monoclonal Antibody Compared With Traditional Anticancer Drugs: An Analysis of Henan Province Spontaneous Reporting System Database

Introduction: Monoclonal antibody (mAb) is an important treatment option for cancer patients and has received widespread attention in recent years. In this context, a comparative safety evaluation of mAbs and traditional anticancer drugs in real-world is warranted.

Methods: ADR reports submitted to Henan Adverse Drug Reaction Monitoring Center from 2016 to 2020 for individuals taking antineoplastic drugs were included. Data were analyzed with respect to demographic characteristics, disease types, polypharmacy, past history of ADRs, system organ class, name of suspected drugs per ADR report, severity, result, impact on the primary disease, and biosimilars.

Results: A total of 15,910 ADR reports related to antineoplastic drugs were collected, 575 (3.61%) cases were related to mAbs. Female had more reports of ADRs than male. The ADRs of non-mAbs mainly occurred in 1–3 days after injection (4,929, 32.15%), whereas those of mAbs mainly occurred on the same day (297, 51.65%). Serious ADRs accounted for 30.26% (n = 174) of mAb-related reports and 34.46% (n = 5,285; four death cases) of non-mAb-related reports, respectively. A total of 495 (86.08%) reports were related to the branded drugs of mAbs. In general, our findings indicate that the female, the population aged 60–79 years, people with a single disease, people who have no ADRs in the past and people who have received treatment regimens were less likely to be affected by the primary disease after receiving mAbs therapy. The signal mining method produced 14 signals, only Sintilimab-Hepatic failure was off-label ADR.

Conclusion: This study partly confirmed the safety profile of mAbs. It is unlikely to affect groups such as the female, the population aged 60-79 years, people with a single disease, people who have no ADRs in the past and people who have received treatment regimens. Combined drugs have little effect on the primary disease. By conducting signal mining method, 14 signals were produced, and only one of them was off-label ADR.

Assessment of Functional Characterization and Comparability of Biotherapeutics: a Review

The development of monoclonal antibody (mAb) biosimilars is a complex process. The key to their successful development and commercialization is an in-depth understanding of the key product attributes that impact safety and efficacy and the strategies to control them. Functional assessment of mAb is a crucial part of the comparability of biopharmaceutical drugs. The development of a relevant and robust functional assay requires an interdisciplinary approach and sufficient flexibility to balance regulatory concerns as well as dynamics and variability during the manufacturing process. Although many advanced tools are available to study and compare the potency and bioactivity of the protein, most of these techniques suffer from major shortcomings that limit their routine use. These include the complexity of the task, establishment of the relevance of the chosen method with the mechanism of action (MOA) of the biosimilar, cost and extended time of analysis, and often the ambiguity in interpretation of the resulting data. To overcome or to address these challenges, the use of multiple orthogonal state-of-the-art techniques is a necessary prerequisite.

Physicochemical and functional characterization of HS016, a biosimilar of adalimumab (Humira)

The characterization of a biosimilar drug HS016, the reference product adalimumab (Humira), and their biosimilarities were determined using physical chemistry and functional similarity tests. The primary and higher order structures, size and charge variants, glycosylation profiles, and in vitro potency of both antibodies were characterized both for unstressed and stability samples. Slight differences were observed in the relative levels of methionine oxidation, low molecular weight components, terminal lysine variant, high mannoses and galactosylated glycans between HS016 and Humira. However, no differences in antigen binding activity, Fc receptor affinity, antibody-dependent cell-mediated cytotoxicity or complemented-dependent cytotoxicity were found. The primary and higher order structures, physicochemical properties, and biological activity of HS016 and adalimumab were similar.

Isolation, physicochemical, and structure-function relationship of the hydrophobic variant of Fc-fusion proteins that bind to TNF-α receptor, HS002 and HS002A

HS002 is the recombinant human tumor necrosis factor-α receptor Ⅱ: IgG Fc fusion protein licensed in China to treat rheumatism and psoriasis. The aim of this study was to isolate and characterize the hydrophobic freeze-dried powder injection (HS002) and ampoule injection (HS002A) variants derived from proteins of the same sequence and then to explore the structure-function relationship. Extensive physicochemical and structural testing was performed during a side-by-side comparison of the monomer peak and variant. Then the TNF-α-related binding activity, cell biological activity and affinity with FcRn were analyzed. Finally, a transformation study of the hydrophobic variant was performed under serum-like redox conditions. This research revealed that HS002A has similar physicochemical and structure-function relationship profiles to those of HS002. The hydrophobic variant exhibited the presence of new incorrect disulfide bridging. At the same time, this novel disulfide scrambled species structure-function relationship was found to be the molecular basis for reduced TNF-α binding and cell biological activities. In addition, incorrect disulfide bridging was found to be reversible under serum-like redox conditions, restoring TNF-α binding and cell biological activities to almost normal levels, all of which indicate that the variant is probably irrelevant to clinical efficacy once the drug enters the bloodstream.

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.

Comparison of glycoprofiles of rituximab versions licensed for sale in India and an analytical approach for quality assessment

Glycosylation affects clinical efficacy and safety; therefore, is a critical quality attribute of therapeutic monoclonal antibodies. Glycans are often labile and complex in patterns, giving rise to macro- and micro-heterogeneity. Recombinant production, diverse geographical locations, associated transportation and storage conditions further compound the problem. Two-way studies comparing glycoprofile of the originator and its given biosimilar are aplenty. However, the extent of analytical variation and similarity in glycoprofile across all approved versions of a drug is hardly explored. Using UHPLC and mass spectrometry, we compared the glycoprofiles of eight rituximab drug samples licensed for sale in India. While the types of glycans were found identical, the abundance of some glycans varied significantly within the tested population. The quality range of glycosylation parameters of the tested sample population differed significantly from the previously established values for US/EU licensed rituximab. As the mean abundance of the 90% of identified glycans falls within ±3SD, the extent of mutual variations amongst tested lots is less significant compared to the extreme deviation from previously established QR limits. Thus, we propose this approach as an orthogonal method to capture glycan variations in licensed versions of mAbs for quality surveillance and in cases where originator samples' are limiting. SIGNIFICANCE: As fluctuation in glycosylation may be of clinical significance, we identify that a one-to-one comparison with originator alone is insufficient in sensing the extent of variations in glycosylation parameters in licensed biosimilars of a given therapeutic mAb. Here we propose that future biosimilarity analysis may include an orthogonal approach of generating an additional combined QR range representing variations across the originator and its biosimilars. The glycosylation profiles of eight rituximab drug samples of different make obtained from the point of sale in India were found identical amongst the tested rituximab versions. However, the QR limits corresponding to important glycosylation parameters differed significantly across all tested samples from the previously established QR limits of US- and EU-licensed rituximab in statistical terms. Such an approach may be useful in defining the true range of glycan variations in licensed versions of therapeutic mAbs.

Biosimilar or Not: Physicochemical and Biological Characterization of MabThera and Its Two Biosimilar Candidates

The development of therapeutic biosimilar antibodies has become an important driving force of the modern biopharmaceutical industry. In this study, physiochemical characteristics (amino acid sequence, intact/subunit molecular weight, isoelectric point, post-translation modification, and disulfide linkage pattern), purity (charge variants, high and low molecular weight variants), antigen binding activity, Fc receptor binding affinity and Fc-effector function (CDC and ADCC) were analyzed by using an extensive set of state-of-the-art and orthogonal analytical technologies to provide a comprehensive characterization of the innovative product rituximab and two biosimilar candidates. The similarity study showed that biosimilar candidate 1 (BC1) and the reference product (RP) MabThera had an identical protein amino acid sequences and highly similar primary structures along with similar purity, heterogeneity profiles, antigen binding activity, Fc receptor binding affinity, and Fc-effector functions. Biosimilar candidate 2 (BC2), which had an amino acid replacement at a constant region, a different N-glycosylation profiling, and purity, was not analytically similar to RP. Although BC2 showed improvement such as an increased level of afucose, another IgG1 allotype, and similar biological activities, it was not recommended to be applied as a biosimilar compound in drug registration because the biosimilar manufacturer must first show that its primary structure was identical to that of RP. Our physicochemical characterizations and bioassay comparability study provided a deepened understanding of the structure-function relationship of quality attributes.

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.

Isolation and characterization of charge variants of infliximab biosimilar HS626

Charge variants are the most commonly observed sources of heterogeneity in the routine manufacturing of monoclonal antibodies. To gain further insight into the structural foundation of charge heterogeneity and its influence on biological functions, an infliximab biosimilar HS626 from a biopharmaceutical facility was isolated by semipreparative cation exchange chromatography (CEX) to obtain fractions of acidic and basic charge variants and determine the main species. It was assessed again by CEX to ensure purities. Through a series of structural and physicochemical characterizations, we concluded that the acidic variants were caused by fragments, Met oxidation, Asn deamidation, higher levels of sialylation and galactosylation of N-linked glycans, and less high mannose. The basic variants resulted mainly from aggregates, fragments, and Met oxidation. Through further analysis of antigen binding affinity, cell death inhibitory activity, ADCC, and CDC, as well as FcRn, FcγRIIIa, and C1q affinity, we demonstrated that the charge heterogeneity did not affect biological functions. This research enhances the understanding of charge variants, which are usually effective components that should not be intentionally reduced unless biological functions are affected.

Phase 1 studies comparing safety, tolerability, pharmacokinetics and pharmacodynamics of HLX01 (a rituximab biosimilar) to reference rituximab in Chinese patients with CD20-positive B-cell lymphoma

Objective

This study aimed to compare the pharmacokinetic, pharmacodynamic and safety profiles of HLX01 (a rituximab biosimilar) and reference rituximab sourced from China (MabThera^®; rituximab-CN).

Methods

Here we report the results of two phase 1 studies. In the phase 1a, open-label, dose-escalation study (NCT03218072, CTR20140400), eligible patients received 250, 375 and 500 mg/m² HLX01 sequentially at 7-day intervals, after confirming no dose-limiting toxicity (DLT). In the phase 1b, double-blind study (NCT02584920, CTR20140764), eligible patients were given a single dose of 375 mg/m² HLX01 or rituximab-CN. The primary endpoints included safety and tolerability parameters for the phase 1a and the area under the plasma concentration-time curve from time zero to day 91 (AUC_{0−91 d}) for the phase 1b study. Equivalence was concluded if 90% confidence interval (90% CI) for the geometric least squares mean ratio (GLSMR) fell in the pre-specified equivalence criteria (80%−125%).

Results

Between June 20, 2014 and January 5, 2015, 12 patients were enrolled in the phase 1a study. The pharmacokinetics of HLX01 showed dose proportionality and accumulation to steady state. HLX01 was well tolerated, with no serious adverse events (AEs), discontinuations or DLTs. Between November 8, 2014 and August 13, 2015, 87 eligible patients were enrolled in the phase 1b study, including 43 who received HLX01 and 44 who were treated with rituximab-CN. The equivalence endpoint was met with GLSMR for AUC_{0−91 d} being 89.6% (90% CI: 80.4%−99.8%). AEs, anti-drug antibodies, and CD19+ and CD20+ B lymphocyte counts were similar between the HLX01 and rituximab-CN treatment groups.

Conclusions

Treatment with HLX01 was safe and well tolerated in Chinese patients with B-cell lymphoma. HLX01 and rituximab-CN have similar pharmacokinetic, pharmacodynamic and safety profiles.

Demonstrating Analytical Similarity of Trastuzumab Biosimilar HLX02 to Herceptin® with a Panel of Sensitive and Orthogonal Methods Including a Novel FcγRIIIa Affinity Chromatography Technology

BACKGROUND

A biosimilar needs to demonstrate its similarity to the originator reference product (RP) in terms of structural and functional properties as well as nonclinical and clinical outcomes.

OBJECTIVES

The aim was to assess the analytical similarity between the trastuzumab biosimilar HLX02 and Europe-sourced Herceptin® (EU-Herceptin®) and China-sourced Herceptin® (CN-Herceptin®) following a quality-by-design (QbD) quality study and tier-based quality attribute evaluation.

METHODS

A panel of highly sensitive and orthogonal methods, including a novel Fc gamma receptor IIIa (FcγRIIIa) affinity chromatography technique that enables quantitative comparison of glycan effects on effector function, was developed for the assessment. To ensure the full product variability was captured, ten batches of HLX02 were compared with 39 RP batches with expiry dates from August 2017 to March 2021.

RESULTS

The extensive three-way similarity assessment demonstrated that HLX02 is highly similar to the RPs. Furthermore, the %afucose, %galactose, and FcγRIIIa affinity of the RPs were observed to first decrease and then return to the original level in relation to their expiry dates, and the RP batches can be subgrouped by their FcγRIIIa affinity chromatograms. HLX02 is demonstrated to be more similar to the RPs of the high FcγRIIIa affinity group.

CONCLUSION

Besides having an overall high analytical similarity to both EU-Herceptin® and CN-Herceptin®, HLX02 is more similar to Herceptin® with high FcγRIIIa affinity, a result that demonstrates the power of the novel FcγRIIIa affinity chromatography technology in biosimilarity evaluation.

Quality by Design-Based Assessment for Analytical Similarity of Adalimumab Biosimilar HLX03 to Humira®

Quality by design (QbD) is an efficient but challenging approach for the development of biosimilar due to the complex relationship among process, quality, and efficacy. Here, the analytical similarity of adalimumab biosimilar HLX03 to Humira® was successfully established following a QbD quality study. Quality target product profile (QTPP) of HLX03 was first generated according to the public available information and initial characterization of 3 batches of Humira®. The critical quality attributes (CQAs) were then identified through risk assessment according to impact of each quality attribute on efficacy and safety. The anticipated range for each CQA was derived from similarity acceptance range and/or the corresponding regulatory guidelines. Finally, a panel of advanced and orthogonal physicochemical and functional tests and comparison of 6 batches of HLX03 and 10 batches of the reference standard demonstrated high similarity of HLX03 to Humira®, except for slightly lower percentage of high mannosylated glycans (%HM) in HLX03 which had no effect on FcγRIII binding and antibody-dependent cell-mediated cytotoxicity (ADCC) activity in human peripheral blood mononuclear cell (PBMC). All above demonstrated the feasibility and efficiency of QbD-based similarity assessment of a biosimilar monoclonal antibody (mAb).

A phase 3 study of rituximab biosimilar HLX01 in patients with diffuse large B-cell lymphoma

Rituximab in combination with chemotherapy has shown efficacy in patients with diffuse large B-cell lymphoma (DLBCL) for more than 15 years. HLX01 was developed as the rituximab biosimilar following a stepwise approach to demonstrate biosimilarity in analytical, pre-clinical, and clinical investigations to reference rituximab. With demonstrated pharmacokinetic similarity, a phase 3 multi-center, randomized, parallel, double-blind study (HLX01-NHL03) was subsequently conducted to compare efficacy and safety between HLX01 plus cyclophosphamide, doxorubicin, vincristine, and prednisone (H-CHOP) and reference rituximab plus CHOP (R-CHOP) in a total of 407 treatment-naïve, CD20-positive DLBCL patients aged 18–80 years. The primary efficacy endpoint was best overall response rate (ORR) within six cycles of treatment in the per-protocol set (PPS). Secondary endpoints included 1-year efficacy outcomes, safety, and immunogenicity profile. The results showed difference in ORRs [H-CHOP 94.1%; R-CHOP 92.8%] between two treatment groups was 1.4% (95% confidence interval [CI], − 3.59 to 6.32, p = 0.608) which falls within the pre-defined equivalence margin of ± 12%. The safety profile was comparable between the treatment groups, with a similar overall incidence of treatment-emergent adverse events (H-CHOP 99.5%, R-CHOP 99.0%, p = 1.000) and serious adverse events (H-CHOP 34.0%, R-CHOP 32.5%, p = 0.752). This study established bioequivalence in efficacy and safety between HLX01 and reference rituximab. The trial was registered at http://www.chinadrugtrials.org.cn on 26 August 2015 [#CTR20150583].