Brief Report: Safety and Immunogenicity of Rituximab Biosimilar GP 2013 After Switch From Reference Rituximab in Patients With Active Rheumatoid Arthritis

Biosimilars in the treatment of rheumatoid arthritis: a pharmacokinetic overview

INTRODUCTION

As of May 2023, 19 and 18 biosimilars have been approved for the treatment of rheumatoid arthritis (RA) by the European Medicines Agency (EMA) and United States Food and Drug Administration (US FDA) respectively.

AREA COVERED

Pharmacokinetic results of phase 1 studies of approved biosimilars were reviewed by systematic literature search. The impact of immunogenicity on the pharmacokinetic data and clinical response was assessed, and the potential benefit of monitoring serum concentrations of biologic drugs is discussed. The advantage of subcutaneous CT-P13 (an infliximab biosimilar) in clinical practice is reviewed.

EXPERT OPINION

Biosimilars are approved based on the totality of evidence including comparable physiochemical properties, PK / PD profiles, and clinical efficacy and safety to the originator. To utilize biosimilars more effectively, physicians should be aware of the utility of combination DMARD therapy to reduce immunogenicity and maintain efficacy and PK profile. PK monitoring, however, is not currently recommended in clinical practice. CT-P13 subcutaneous (SC) is the first SC infliximab used for treatment of RA patients. Based on data from clinical studies and the real world, SC-infliximab is an attractive therapeutic option compared to IV formulations of infliximab based on its efficacy, pharmacokinetics, patient-reported outcomes, and safety profile.

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.

Real-world experience of rituximab biosimilar GP2013 in rheumatoid arthritis patients naïve to or switched from reference rituximab

Randomized controlled trials showed high comparability of biosimilar rituximab (bs-RTX) GP2013 to biologic originator RTX (bo-RTX). Data on effectiveness of switching from bo-RTX to bs-RTX, starting therapy with bs-RTX, and bs-RTX drug survival in real-world setting are sparse. To explore long-term drug effectiveness and survival of bs-RTX GP2013 in rheumatoid arthritis (RA) patients both naïve to and mandatory switched from bo-RTX, and to clarify reasons for treatment cessation. Retrospective observational cohort study including RA outpatient clinic patients treated with bs-RTX between 2018 and 2021 in Norway. Patients were examined and monitored using recommended measures for disease activity and patient-reported outcomes (PROs). For description of population medians and interquartile range were used. Difference between observation times was assessed with Signed-Rank test, drug survival with Kaplan-Meier survival analysis. Reasons for discontinuation were ascertained. Among 110 patients, at baseline, 88 were mandatory switched from bo-RTX and 22 were RTX-naïve. During 2-year follow-up, disease activity and PROs measures remained stable in switchers subgroup and improved in subgroup starting bs-RTX for the first time. Overall drug survival was 80.0% after 1 year and 57.7% after 2 years and was significantly higher in bs-RTX-switched than in bs-RTX-naïve patients (p = 0.036). Two most frequently reported reasons for drug discontinuation were remission (38.6%) and doctor's decision (27.1%). RA patients treated with bs-RTX had satisfactory treatment response and drug retention rates which supports equivalence of bs-RTX GP2013 to bo-RTX, both in patients naïve to and mandatory switched from bo-RTX.

Severe Hypersensitivity Reactions at Biosimilar versus Originator Rituximab Treatment Initiation, Switch and Over Time: A Cohort Study on the French National Health Data System

BACKGROUND

Biosimilar products of rituximab came to market in 2017. French pharmacovigilance centers have highlighted an excess of case reports of severe hypersensitivity reactions related to their use compared with the originator product.

OBJECTIVE

The aim of this study was to assess the real-world association between biosimilar versus originator rituximab injections and hypersensitivity reactions, among initiators and switchers, at first injection and over time.

METHODS

The French National Health Data System was used to identify all rituximab users between 2017 and 2021. A first cohort consisted of patients who initiated rituximab (originator or biosimilar), while a second cohort consisted of originator-to-biosimilar switchers, matched on age, sex, deliveries history, and pathology, with one or two patients still receiving the originator product. The event of interest was defined as a hospitalization for anaphylactic shock or serum sickness following a rituximab injection.

RESULTS

A total of 91,894 patients were included in the initiation cohort-17,605 (19%) with the originator product and 74,289 (81%) with a biosimilar. At initiation, 86/17,605 (0.49%) and 339/74,289 (0.46%) events occurred in the originator and biosimilar groups, respectively. The adjusted odds ratio of biosimilar exposure associated with the event was 1.04 (95% confidence interval [CI] 0.80-1.34), and the adjusted hazard ratio for biosimilar versus originator exposure was 1.15 (95% CI 0.93-1.42), showing no increased risk of event with biosimilar use at first injection, and over time. 17,123 switchers were matched to 24,659 non-switchers. No association was found between switch to biosimilars and occurrence of the event.

CONCLUSION

Our study does not support any association between exposure to rituximab biosimilars versus originator and hospitalization for a hypersensitivity reaction, either at initiation, at switch, or over time.

Biosimilars: Harmonizing the Approval Guidelines

Biosimilar approval guidelines need rationalization and harmonization to remove the inconsistencies and misconceptions to enable faster, safer, and more cost-effective biosimilars. This paper proposes a platform for a model guideline based on the scientific evaluation of the regulatory filings of the 130+ products approved in the US, UK, and EU and hundreds more in the WHO member countries. Extensive literature survey of clinical data published and reported, including Clinicaltrials.gov, a review of all current guidelines in the US, UK and EU, and WHO, and detailed discussions with the FDA have confirmed that removing the animal and clinical efficacy testing and fixing other minor approaches will enable the creation of a harmonized guideline that will best suit an ICH designation.

A Developer's Perspective on Clinical Evidence and Benefits for Rituximab Biosimilar Uptake, with a Focus on CT-P10

To date, four rituximab biosimilars have received regulatory approval from the European Medicines Agency and/or US Food and Drug Administration. CT-P10 was the first rituximab biosimilar to be approved by each agency, in 2017 and 2018, respectively. Regulatory approval of CT-P10 followed demonstration of pharmacokinetic equivalence to the reference product in a phase I study in patients with rheumatoid arthritis. Phase III pivotal studies of CT-P10 subsequently demonstrated equivalence or non-inferiority of pharmacokinetics and efficacy between CT-P10 and reference rituximab in patients with rheumatoid arthritis, advanced-stage follicular lymphoma, and low-tumour-burden follicular lymphoma. Almost 5 years after its initial regulatory approval, significant real-world experience has accumulated with CT-P10 use, particularly in diffuse large B-cell lymphoma, one of the indications approved by extrapolation. This article summarises the pivotal data underlying regulatory approval for the four licensed rituximab biosimilars, before focusing on real-world data gathered with CT-P10. These data provide further support for the safety and effectiveness of CT-P10 and should boost healthcare professional and patient confidence in its use. Pharmacoeconomic analyses support the potential healthcare system cost savings offered by rituximab biosimilar uptake, which could lead to improved patient access to biologic treatments. Opportunities arising from biosimilar uptake extend further, potentially enabling innovative investigator-led research and therapeutic advances.

Immunogenicity of Rituximab biosimilar GP2013 in chronic inflammatory rheumatic disorders in daily clinical practice

OBJECTIVE

To study in daily practice the risk of immunogenicity of patients treated with the biosimilar rituximab (RTX) GP2013 used for chronic inflammatory rheumatic disorders.

METHODS

A prospective monocentric routine care study was carried out between September 2018 and May 2021, including consecutive patients treated with the biosimilar RTX GP2013. Biosamples were taken before each infusion to quantify anti-RTX antibodies (ADAbs) and serum RTX trough levels by ELISA (Lisa Tracker Duo Rituximab, LTR005, Theradiag).

RESULTS

168 GP2013-treated patients were included (129 who switched from originator RTX and 39 originator RTX naïve). The analysis of 602 samples identified 15 patients (8%) with positive ADAbs including 6 and 9 with transient and persistent ADAbs, respectively. The switch from originator RTX to GP2013 did not increase the risk of immunogenicity, with an incidence rate of 0.8 for 100 patient years. The frequency of persistent ADAs was higher in non-RA patients (5/56, 9% vs. 4/112, 3.5%). Patients with positive persistent ADAbs were more frequently non-caucasian (7/9, 78%, vs. 56/159, 35%, p<0.01) and all had detectable circulating B cells (vs. 40% in ADAb-negative patients, P<0.001). ADAb positivity was not associated with disease activity or RTX discontinuation but patients with ADAb titers >100 ng/mL experienced reduced treatment efficacy or severe infusion-related reaction.

CONCLUSION

Within the study duration, the immunogenicity of GP2013 is a rare event affecting the pharmacodynamics of RTX. Although development of ADAbs had no impact on treatment discontinuation, possible harmful consequences may be observed in patients with high antibody levels.

Regulatory Evaluation of Biosimilars: Refinement of Principles Based on the Scientific Evidence and Clinical Experience

The World Health Organization (WHO) guidelines on evaluation of similar biotherapeutic products (SBPs; also called biosimilars) were adopted by the WHO Expert Committee on Biological Standardization (ECBS) in 2009. In 2019, the ECBS considered that a more tailored and potentially reduced clinical data package may be acceptable in cases where this was clearly supported by the available scientific evidence. The goal of this publication is to review the current clinical experience and scientific evidence and to provide an expert perspective for updating the WHO guidelines to provide more flexibility and clarity. As the first step, the relevant guidelines by other regulatory bodies were reviewed in order to identify issues that might help with updating the WHO guidelines. Next, a literature search was conducted for information on the long-term efficacy, safety, and immunogenicity of biosimilars to identify possible long-term problems. Finally, a search for articles concerning the role of clinical studies in the benefit-risk evaluation of biosimilars was conducted. The analysis of other guidelines suggested that the WHO guidelines may need more emphasis on the importance of the state-of-the-art physicochemical and structural comparability exercise and in vitro functional testing. The use of "foreign" reference product will also need clarifications. The value of in vivo toxicological tests in the development of biosimilars is questionable, and the non-clinical part needs revisions accordingly. The concepts of "totality of evidence," "stepwise development," and "residual uncertainty" were applied in the evaluation of the clinical sections of the guideline. The review of long-term safety and efficacy demonstrated the robustness of the current biosimilar development concept. The analysis of the roles of different development phases suggested that the large efficacy, safety, and immunogenicity studies are, in most cases, redundant. The residual uncertainty of safety, immunogenicity, and efficacy of biosimilars that has shaped the current regulatory guidelines is now substantially reduced. This will allow the re-evaluation of the non-clinical and clinical requirements of the current WHO main guideline. The shift of the relative impact of the development phases towards physico-chemical and in vitro functional testing will provide a relief to the manufacturers and new challenges to the regulators.

Comparison of treatment retention of originator vs biosimilar products in clinical rheumatology practice in Sweden

OBJECTIVES

To compare treatment retention between biosimilars and their originator products among first starters (etanercept, infliximab, adalimumab and rituximab), as well as after non-medical switch.

METHODS

Patients with rheumatic diseases starting, for the first time, an originator or biosimilar etanercept, infliximab, adalimumab, and rituximab were identified in the national Swedish Rheumatology Quality register. Moreover, patients switching from an originator to its biosimilar were identified, and individually matched to patients continuing on the originator. One-year treatment retention was calculated, and hazard ratios (HR) for discontinuation with 95% confidence intervals (CI) were estimated, adjusting for comorbidities and socioeconomic factors.

RESULTS

In total, 21443 first treatment courses were identified. The proportion of patients still on drug at one year, and the HR for discontinuation, revealed no differences across adalimumab (Humira, Imraldi, Amgevita and Hyrimoz) nor across rituximab products (Mabthera, Ritemvia/Truxima and Rixathon). The proportions on drug at one year were similar for Benepali (77%) and Enbrel (75%) and the adjusted HR for Benepali compared to Enbrel was 0.91 (95% CI: 0.83-0.99). For infliximab, the proportion still on drug at one year was 67% for Remicade and 66% for Remsima/Inflectra, and the HR in comparison with Remicade was: 1.16 (95% CI: 1.02-1.33).Among 2925 patients switching from an originator drug to one of its biosimilars, we noted no statistically significant or clinically relevant differences in drug survival compared those who remained on originator therapy.

CONCLUSION

This large observational study supports the equivalence of bDMARD biosimilar products and originators when used in routine rheumatology care.

Efficacy and safety of Sandoz biosimilar rituximab for active rheumatoid arthritis: 52-week results from the randomized controlled ASSIST-RA trial

OBJECTIVES

This report provides data for the extent of B cell depletion and recovery, efficacy, safety and immunogenicity of Sandoz rituximab (SDZ-RTX; GP2013; Rixathon®) compared with reference rituximab (Ref-RTX) up to week 52 of the ASSIST-RA study.

METHODS

Patients were randomized to SDZ-RTX or Ref-RTX in combination with methotrexate according to the RTX label. The primary endpoint was analysed at week 24. Responders (28-joint DAS [DAS28] decrease from baseline >1.2) at week 24 with residual disease activity (DAS28 ≥2.6) were eligible for a second treatment course between week 24 and 52. Endpoints after week 24 included change from baseline in peripheral B cells, DAS28, ACR 20% response rate (ACR20), Clinical and Simplified Disease Activity Indexes (CDAI, SDAI) and HAQ disability index (HAQ-DI). Safety and immunogenicity were assessed by the incidence of adverse events and antidrug antibodies.

RESULTS

Primary and secondary endpoints up to week 24 were met. Overall, 260/312 randomized patients completed treatment up to week 52. SDZ-RTX resulted in B cell concentrations over time similar to Ref-RTX. The efficacy of SDZ-RTX was similar to Ref-RTX up to week 52, as measured by DAS28, ACR20/50/70, CDAI, SDAI and HAQ-DI. Safety of SDZ-RTX was similar to Ref-RTX regarding frequency, type and severity of adverse events, which were consistent with the known Ref-RTX safety profile. The incidence of antidrug antibodies was low and transient similarly across treatment groups.

CONCLUSION

SDZ-RTX demonstrated similar B cell concentrations over time, efficacy, safety and immunogenicity to Ref-RTX over 52 weeks of the ASSIST-RA study.

Therapeutic Recommendations for the Management of Older Adult Patients with Sjögren's Syndrome

Primary Sjögren's syndrome (SjS) is a systemic autoimmune disease most commonly diagnosed in middle-aged women. Although the disease can occur at all ages, it is diagnosed between 30 and 60 years of age in two-thirds of patients. In more than 20% of cases, the people are older than 65 years. In this review, we focus on the therapeutic management of primary SjS in older patients, following the recently published 2020 European League Against Rheumatism (EULAR) recommendations for the management of the disease with topical and systemic therapies. These recommendations are applicable to all patients with primary SjS regardless of age at diagnosis, although the therapeutic management in older patients requires additional considerations. Older patients are more likely to have pulmonary, liver, kidney, or heart-related comorbidities (even cognitive disturbances); caution is required when most drugs are used, including muscarinic agents, systemic corticosteroids and synthetic immunosuppressants. It is also important to monitor the use of eye drops containing steroids due to the increased risk of developing cataracts, a frequent ocular complication in the older population. In contrast, the majority of drugs that can be used topically (pilocarpine rinses, eye drops containing topical non-steroidal anti-inflammatory drugs (NSAIDs) or cyclosporine A, topical dermal formulations of NSAIDs) have shown an acceptable safety profile in older patients, as well as rituximab. A rigorous evaluation of the medical history of older patients is essential when drugs included in the EULAR guidelines are prescribed, with special attention to factors frequently related to ageing, such as polypharmacy, the existence of organ-specific comorbidities, or the enhanced susceptibility to infections.

Immunogenicity of Biosimilars for Rheumatic Diseases, Plaque Psoriasis, and Inflammatory Bowel Disease: A Review from Clinical Trials and Regulatory Documents

The goal of this narrative review was to summarize immunogenicity data of biosimilars or biosimilar candidates for rheumatic diseases, plaque psoriasis, or inflammatory bowel disease (IBD), available in peer-reviewed publications or regulatory documents. PubMed records and regulatory documents were searched for immunogenicity data of TNFα or CD20 inhibitor biosimilars or biosimilar candidates. Data collected included the proportion of patients positive for anti-drug antibodies (ADAbs), proportion with neutralizing antibodies (nAbs) among ADAb-positive patients, ADAb/nAb assay characteristics, cross-reactivity, and the effects of ADAbs on pharmacokinetics, pharmacodynamics, efficacy, and safety. We identified eight biosimilars or biosimilar candidates for adalimumab (BI 695501, SB5, ABP 501, GP2017, PF-06410293, MSB-11022, FKB-327, ZRC-3197) four for etanercept (SB4, GP2015, CHS-0214, LBEC0101), and three each for infliximab (SB2, CT-P13, GP1111) and rituximab (CT-P10, GP2013, PF-05280586) with immunogenicity data. Randomized, head-to-head trials with reference products varied in design and methodology of ADAb/nAb detection. The lowest proportions of ADAb-positive (0–13%) and nAb-positive patients (0–3%) were observed in the trials of etanercept and its biosimilars, and the highest with adalimumab, infliximab, and their biosimilars (ADAbs: ≤ 64%; nAbs: ≤ 100%). The most common method of ADAb detection was electrochemiluminescence, and ADAb positivity was associated with nominally inferior efficacy and safety. Overall, there were no significant immunogenicity differences between biosimilars and reference products. However, there are many discrepancies in assessing and reporting clinical immunogenicity. In conclusion, immunogenicity data of biosimilars or biosimilar candidates for TNFα or CD20 inhibitors were collected in trials that varied in design and procedures for ADAb/nAb detection. In general, immunogenicity parameters of biosimilars are similar to those of their reference products.

Real-world use and acceptance of rituximab biosimilars in non-Hodgkin lymphoma in an oncologist network in Germany

Aim: Present real-world data for rituximab (biosimilar and reference)-containing regimens in extrapolated indications in non-Hodgkin lymphoma (NHL)/chronic lymphocytic leukemia (CLL). Patients & methods: Data collected from office-based oncologic practices in Germany (July 2017–June 2019). Results: Of 1741 patients, 1241 had NHL; 500 had CLL. Of 7595 therapy cycles, 28.3% used reference rituximab; 55.2% used rituximab biosimilars; 2.0% used subcutaneous rituximab; 14.5% used rituximab, not otherwise specified. Rituximab biosimilars were used across all indications; 57.3% of cycles were administered in extrapolated indications. Over 24 months, the proportion of rituximab prescriptions that were for biosimilars increased from 12.0 to 83.0%. Conclusion: Our real-world data in NHL and CLL depicts increasing use of rituximab biosimilars across multiple treatment protocols, including extrapolated indications.

Rituximab biosimilars for lymphoma in Europe

Introduction: The approval of rituximab, a monoclonal antibody targeting CD20, revolutionized the treatment of B-cell non-Hodgkin lymphomas and became an undisputed standard of care. However, as with all biologic medicines, the complex development and manufacturing process for rituximab have meant that the medicine attracts high treatment costs. Approved rituximab biosimilars have been comprehensively demonstrated to match the reference medicine. With the potential to increase access to biologic therapy, they have a key role in helping to improve patient outcomes in lymphoma care. Areas covered: In this review, we discuss the role of rituximab in the treatment of lymphoma. We explore development and regulatory requirements for biosimilar development and the potential impact of these medicines on access and sustainability. Focusing on biosimilars of rituximab, we examine in detail the evidence for biosimilarity for the two rituximab biosimilars that are approved in Europe and provide an overview of rituximab biosimilars currently in development. Expert opinion: We foresee a wider uptake of biosimilar medicines for lymphoma treatment over the next 5 years. The associated cost savings should be invested in broadening patient access to biological therapies, enabling wider use of more expensive treatment strategies and driving innovation in cancer care.

A comprehensive review of rituximab therapy in rheumatoid arthritis patients

Rituximab (RTX) is an approved treatment for rheumatoid arthritis (RA) patients that do not respond adequately to disease-modifying antirheumatic drugs. However, different new concerns, such as efficacy, optimum dose, safety issues, prediction of response to RTX, and pregnancy outcomes have attracted a lot of attention. The PubMed database was systematically reviewed for the last published articles, new findings, and controversial issues regarding RTX therapy in RA using "Rheumatoid arthritis" AND "rituximab" keywords, last updated on June 18, 2019. From 1812 initial recorders, 162 studies met the criteria. Regarding the optimum dose, low-dose RTX therapy (2 × 500 mg) seems as effective as standard dose (2 × 1000 mg), safer, and more cost-effective. The most common reported safety challenges included de novo infections, false negative serologic tests of viral infections, reactivation of chronic infections, interfering with vaccination outcome, and development of de novo psoriasis. Other less reported side effects are infusion reactions, nervous system disorders, and gastrointestinal disorders. Lower exposure to other biologics, presence of some serological markers (e.g., anti-RF, anti-CCP, IL-33, ESR), specific variations in FCGR3A, FCGR2A, TGFβ1, IL6, IRF5, BAFF genes, and also EBV-positivity could be used to predict response to RTX. Although there is no evidence of the teratogenic effect of RTX, it is recommended that women do not expose themselves to RTX at least 6 months before the conception. Only a reversible reduction of B cell-count in the offspring may be the pregnancy-related outcome. Although RTX is an effective therapeutic option for RA, more studies on optimum doses, prevention of RTX-related side effects, prediction of RTX response, and safety during the pregnancy are required.

Switching to biosimilars: current perspectives in immune-mediated inflammatory diseases

Introduction: The expiry of patents for biologics has led to the introduction of biosimilars for the treatment of immune-mediated inflammatory diseases (IMIDs). These treatment alternatives may allow earlier and wider access to appropriate therapy for patients without increasing the economic burden on health-care systems. Prescription of biosimilars to treatment-naïve patients is well accepted; however, additional considerations must be taken into account when switching clinically stable patients from reference products to biosimilars. Area covered: We discuss the current considerations related to switching from reference products to biosimilars from a physician and patient perspective. We review the clinical data and real-life experience on switching patients with IMIDs, present the position of the relevant medical societies, and discuss the importance of patient-physician communication and need for shared decision-making. Expert opinion: The introduction of biosimilars provides an opportunity to expand access to treatment for patients with IMIDs across Europe and support the financial sustainability of health-care systems. We anticipate that as the real-world evidence base grows, confirming the results of clinical trials, there will be a corresponding increase in physician and patient acceptance, not only to initiating treatment with a biosimilar, but also to switching medication from a reference product to a biosimilar.