Are we ready to close the discussion on the interchangeability of biosimilars?

Recommendations for Interchangeability in a Growing Biosimilar Market in Latin America

BACKGROUND

Biosimilars offer significant advantages for improving access to biologic treatments in Latin America. However, their uptake has been slow due to misconceptions, regulatory uncertainties, and inadequate pharmacovigilance.

OBJECTIVE

To address these issues, Americas Health Foundation convened a multidisciplinary panel of regional experts in biosimilar use and interchangeability from Latin America. The panel assessed the current landscape and recommended steps to enhance access.

RESULTS

Key recommendations include strengthening biosimilar regulations, ensuring transparent enforcement, implementing robust pharmacovigilance, and promoting collaboration among stakeholders to educate about the safety, efficacy, and economic advantages of biosimilars and their interchangeability.

CONCLUSIONS

By embracing biosimilars and interchangeability, Latin American countries can expand patient access, foster competition, diversify treatment sources, and enhance the sustainability of their healthcare systems. However, achieving these goals requires addressing knowledge gaps and biases among healthcare providers, patients, regulators, and government agencies. This can be accomplished through clear communication and the use of real-world evidence.

Use of Biosimilars: A Systematic Review of Published Position Statements and Recommendations from Health Organisations and Societies

BACKGROUND

Hesitation about using biosimilars still exists among healthcare professionals (HCPs), despite extensive experience with their use. Globally, several health organisations and societies from various specialties have issued biosimilar position statements to guide the use of biosimilars in their specialties. However, it is uncertain how similar or different their positions or recommendations are or whether these positions have evolved with the increased experience and availability of new evidence.

OBJECTIVES

The study aimed to describe and assess the recommendations of published position statements regarding several aspects of biosimilars across specialties and determine whether these positions have changed with the emergence of new evidence.

METHODS

We systematically searched for published position statements of biosimilars in online databases and included statements written in English. The search was from the inception of the databases until May 2023. Two reviewers independently extracted the data. Only position statements that included recommendations to guide the use of biosimilars in clinical practice and were issued by health organisations and societies, including expert panels, were included. We synthesised recommendations on five aspects: prescribing practice, extrapolation of indication, interchangeability, treatment initiation with biosimilars in biologic-naïve patients, and pharmacovigilance.

RESULTS

The review included 25 papers involving eight specialties, 16 of which were from European countries, 1 from an international organisation representing 49 countries, and 6 from various countries. The papers were published between 2009 and 2020, with 19 published between 2015 and 2020. Of the five aspects of biosimilars assessed, nearly half (11 of 25) of the papers at the time they were published did not base their positions on a scientific or evidence-based approach. Only 4 of the 25 position papers were identified as revisions of their previous papers. With increasing experience in biosimilars and the emergence of new evidence, about 60% (16 of 25) of the papers contained outdated recommendations, particularly on two aspects. They were extrapolations of indications and interchangeability (including switching). The recommendations for most papers for three other aspects were still appropriate. These were prescribing biosimilars by their brand name and active ingredient, initiating treatment with biosimilars in biologic-naïve patients, and monitoring the long-term safety of biosimilars through pharmacovigilance. For four of the revised papers, their position evolved from opposing indication extrapolation for biosimilars to accepting it, while the position of two papers shifted from not recommending biosimilar switching to permitting the practice. Meanwhile, most papers were against automatic substitution by pharmacists because the evidence for this practice was still limited.

CONCLUSIONS

Across specialties, the variability among the position statements is seen for extrapolation of indications for biosimilars and interchangeability (including switching). This requires a revision, considering the latest evidence and growing experience with the use of biosimilars in extrapolated indications and with switching.

Current challenges and recent advances on the path towards continuous biomanufacturing

Continuous biopharmaceutical manufacturing is currently a field of intense research due to its potential to make the entire production process more optimal for the modern, ever-evolving biopharmaceutical market. Compared to traditional batch manufacturing, continuous bioprocessing is more efficient, adjustable, and sustainable and has reduced capital costs. However, despite its clear advantages, continuous bioprocessing is yet to be widely adopted in commercial manufacturing. This article provides an overview of the technological roadblocks for extensive adoptions and points out the recent advances that could help overcome them. In total, three key areas for improvement are identified: Quality by Design (QbD) implementation, integration of upstream and downstream technologies, and data and knowledge management. First, the challenges to QbD implementation are explored. Specifically, process control, process analytical technology (PAT), critical process parameter (CPP) identification, and mathematical models for bioprocess control and design are recognized as crucial for successful QbD realizations. Next, the difficulties of end-to-end process integration are examined, with a particular emphasis on downstream processing. Finally, the problem of data and knowledge management and its potential solutions are outlined where ontologies and data standards are pointed out as key drivers of progress.

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.

Nurses' Knowledge and Attitudes towards Biosimilar Medicines as Part of Evidence-Based Nursing Practice-International Pilot Study within the Project Biosimilars Nurses Guide Version 2.0

Introduction: The increasing availability of biosimilars can increase patient access to these drugs and reduce the economic burden. Nurses play a key role in the education, administration, pharmacovigilance and management of the side effects of biosimilars. The aim of this study was to assess the knowledge and attitudes of nurses towards biosimilar drugs in different countries. Methods: An international cross-sectional study was conducted from November 2021 to February 2022. The survey was carried out using Computer-Assisted Web Interview (CAWI), sent by the CAWI panel via the website. Results: The results showed that nurses with a greater level of education felt most knowledgeable about biosimilars (χ2 = 105.813, df = 2, p < 0.001). One-third of nurses with a doctorate and a second degree said biosimilars are used in their workplace (χ2 = 48.169, df = 4, p < 0.001); most nurses with a second degree said that they had never heard of biosimilars (41%). Doctorate-level nurses thought knowledge is the key factor to increasing biosimilar uptake (97%). Conclusions: Nurses are not knowledgeable about biosimilars. Most would like to participate in training on biosimilars. This is a very important topic, because biosimilars are constantly evolving in medicine.

Breaking Barriers With Basal Insulin Biosimilars in Type 2 Diabetes

Despite increases in the availability and effectiveness of other therapies, insulin remains an essential treatment for approximately 30 million people with type 2 diabetes worldwide. The development of biosimilars has created the potential for significant health care cost savings and may lead to greater access to basal insulin for vast populations. In this review, we discuss evidence demonstrating equipoise between basal insulin biosimilars and the patented analogs they may replace.

Anti-rheumatoid drugs advancements: New insights into the molecular treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is one of more than 100 types of arthritis. This chronic autoimmune disorder affects the lining of synovial joints in about 0.5% of people and may induce severe joints deformity and disability. RA impacts health life of people from all sexes and ages with more prevalence in elderly and women people. Significant improvement has been noted in the last two decades revealing the mechanisms of the development of RA, the improvement of the early diagnosis and the development of new treatment options. Non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and disease-modifying antirheumatic drugs (DMARDs) remain the most known treatments used against RA. However, not all patients respond well to these drugs and therefore, new solutions are of immense need to improve the disease outcomes. In the present review, we discuss and highlight the recent findings concerning the different classes of RA therapies including the conventional and modern drug therapies, as well as the recent emerging options including the phyto-cannabinoid and cell- and RNA-based therapies. A better understanding of their mechanisms and pathways might help find a specific target against inflammation, cartilage damage, and reduce side effects in arthritis.

The Non-medical Switch from Reference Adalimumab to Biosimilar Adalimumab is Highly Successful in a Large Cohort of Patients with Stable Inflammatory Rheumatic Joint Diseases: A Real-Life Observational Study

Introduction

The adalimumab biosimilar (ADAbio) Amgevita® has a similar efficacy and safety profile as the adalimumab reference (ADA) Humira®. We studied the clinical consequences of a non-medical switch from ADA to ADAbio in adult patients with mainly established rheumatoid arthritis (RA), psoriatic arthritis (PsA), and spondyloarthritis (SpA).

Methods

Patients that received treatment with ADA for at least three months were switched to ADAbio. Data was collected retrospectively from 1 year before the switch up to 6 months after.

Results

A total of 603 patients were switched from ADA to ADAbio (switch group). During a 1-year follow-up, over 93% of all patients underwent a successful transition in terms of disease activity and safety from ADA to biosimilar, supporting the bioequivalence of both drugs in patients with stable inflammatory rheumatic joint diseases. Forty patients (6.6%) switched back to ADA (re-switch group). There were no objective changes in disease activity score in 28 joints using C-reactive protein (DAS28-CRP), or adverse effects before and after the switch between both groups.

Conclusions

In line with earlier reports, the transition to ADAbio went successful in the majority of patients with stable inflammatory rheumatic joint diseases. Patient-reported symptoms without objective signs that indicate a flare of disease activity after the switch to ADAbio are probably explained by nocebo effects. A pre-emptive approach to counteract nocebo effects and stimulate placebo response may have a positive impact on health outcomes for patients and preserve the economic benefits of cost savings that can be achieved by prescribing a biosimilar instead of the reference drug.

Regulatory Information and Guidance on Biosimilars and Their Use Across Europe: A Call for Strengthened One Voice Messaging

Background

Beyond evaluation and approval, European and national regulators have a key role in providing reliable information on biosimilars and the science underpinning their development, approval, and use.

Objectives

This study aims to (i) review biosimilar information and guidance provided by EMA and national medicines agencies and (ii) explore stakeholder perspectives on the role of regulators in enabling acceptance and use of biosimilars.

Methods

This study consists of (i) a comparative review of regulatory information and position statements across medicine agencies (n = 32) and (ii) qualitative interviews with stakeholders in Europe (n = 14).

Results

The comparative analysis showed that regulatory information and guidance about biosimilars offered by national medicines agencies in Europe varies, and is limited or absent in multiple instances. Approximately 40% (13/31) of the national medicines agencies' websites did not offer any information regarding biosimilars, and for about half (15/31) no educational materials were provided. Only less than half of national medicines agencies provided guidance on biosimilar interchangeability and switching (8/31 and 12/31, respectively). Among the national medicines agencies that did offer guidance, the extent (e.g., elaborate position vs. brief statement) and content (e.g., full endorsement vs. more cautious) of the guidance differed substantially. Countries that have a strong involvement in EU level biosimilar regulatory activities generally had more elaborate information nationally. Interviewees underwrote the need for (national) regulators to intensify biosimilar stakeholder guidance, especially in terms of providing clear positions regarding biosimilar interchangeability and switching, which in turn can be disseminated by the relevant professional societies more locally.

Conclusion

This study revealed that, despite strong EU-level regulatory biosimilar guidance, guidance about biosimilars, and their use differs considerably across Member States. This heterogeneity, together with the absence of a clear EU-wide position on interchangeability, may instill uncertainty among stakeholders about the appropriate use of biosimilars in practice. Regulators should strive for a clear and common EU scientific position on biosimilar interchangeability to bridge this gap and unambiguously inform policy makers, healthcare professionals, and patients. Furthermore, there is a clear opportunity to expand information at the national level, and leverage EU-developed information materials more actively in this regard.

The impact of biosimilar insulins on the diabetes landscape

The cost of diabetes care in the United States continues to rise, with insulin costs growing rapidly. Accessibility and affordability of these life-saving medications are concerns for providers and patients that need to be addressed. Availability of biosimilar insulin products may help address these issues by introducing additional competition to the insulin market, but they may also face adoption challenges from patients and health care providers alike. In addition, policymakers at state and federal levels are examining and addressing rising insulin costs through legislative and administrative actions. The purpose of this paper is to review the current US diabetes landscape, highlight the differences between biosimilar insulins and follow-on insulins and considerations for successful adoption of biosimilar insulins, and review the current policy landscape regarding rising insulin costs. DISCLOSURES: This Viewpoints article was supported by Sandoz, Inc. Wagner and Patel are employees of Sandoz, Inc. White was employed by Sandoz, Inc., at the time of this study.

Biosimilar-to-Biosimilar Switching: What is the Rationale and Current Experience?

Over time, clinicians have become increasingly comfortable embracing the prescription of biosimilars-highly similar versions of innovator or reference biological agents-for their patients with inflammatory diseases. Although a switch from a reference product to a licensed biosimilar version (or vice versa) is a medical decision robustly supported by the stepwise accumulation of clinical trial evidence concerning comparable safety, immunogenicity, and efficacy between these products, a switch from one biosimilar to another biosimilar of the same reference product, or a cross-switch, is not. Similarity among biosimilars of a reference product is not a regulatory agency concern and therefore is unlikely to be investigated in randomized controlled trials in the foreseeable future. Yet in clinical practice, across a diverse range of patients, the option to cross-switch from one biosimilar to another can and does arise for valid reasons such as convenience or tolerability issues, or driven by third parties (e.g., payers). In the absence of clinical trial data, clinicians must attempt to objectively evaluate the emerging real-world cross-switching evidence within the context of what is known about the science underpinning a designation of biosimilar. That knowledge then needs to be integrated with what clinicians know about their patients and their disease on a case-by-case basis. This review aims to consolidate relevant emerging real-world data and other key information about biosimilar-to-biosimilar cross-switching for prescribing clinicians. In the absence of clear clinical guidelines addressing this topic at present, this review may serve to facilitate discretionary and educated treatment decision making.

Safety, Immunogenicity and Interchangeability of Biosimilar Monoclonal Antibodies and Fusion Proteins: A Regulatory Perspective

Background

Biosimilars have been used for 15 years in the European Union (EU), and have been shown to reduce costs and increase access to important biological medicines. In spite of their considerable exposure and excellent safety record, many prescribers still have doubts on the safety and interchangeability of biosimilars, especially monoclonal antibodies (mAbs) and fusion proteins.

Objectives

The aim of this study was to analyse the short- and long-term safety and interchangeability data of biosimilar mAbs and fusion proteins to provide unbiased information to prescribers and policy makers.

Methods

Data on the safety, immunogenicity and interchangeability of EU-licensed mAbs and fusion proteins were examined using European Public Assessment Reports (EPARs) and postmarketing safety surveillance reports from the European Medicines Agency (EMA). As recent biosimilar approvals allow self-administration by patients by the subcutaneous route, the administration devices were also analyzed.

Results

Prelicensing data of EPARs (six different biosimilar adalimumabs, three infliximabs, three etanercepts, three rituximabs, two bevacizumabs, and six trastuzumabs) revealed that the frequency of fatal treatment-emergent adverse events (TEAEs), TEAEs leading to discontinuation of treatment, serious adverse events (SAEs), and main immune-mediated adverse events (AEs) were comparable between the biosimilars and their reference products. The availability of new biosimilar presentations and administration devices may add to patient choice and be an emerging factor in the decision to switch patients. Analysis of postmarketing surveillance data covering up to 7 years of follow-up did not reveal any biosimilar-specific adverse effects. No product was withdrawn for safety reasons. This is in spite of considerable exposure to biosimilars in treatment-naïve patients and in patients switched from the reference medicinal product to the biosimilar. Analysis of data from switching studies provided in regulatory submissions showed that single or multiple switches between the originator and its biosimilar versions had no negative impact on efficacy, safety or immunogenicity.

Conclusions

In line with previous reports of prelicensing studies of biosimilar mAbs and etanercepts, this study demonstrated comparable efficacy, safety, and immunogenicity compared with the reference products. This is the first study to comprehensively analyze postmarketing surveillance data of the biosimilar mAbs and etanercept. An analysis of more than 1 million patient-treatment years of safety data raised no safety concerns. Based on these data, we argue that biosimilars approved in the EU are highly similar to and interchangeable with their reference products. Thus, additional systematic switch studies are not required to support the switching of patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40265-021-01601-2.

Treatment journey in rheumatoid arthritis with biosimilars: from better access to good disease control through cost savings and prevention of nocebo effects

Early diagnosis and treatment of rheumatoid arthritis (RA) are of critical importance to halt the progression of the disease. Optimal use of advanced imaging techniques or biomarkers may facilitate early diagnosis of RA. Even though many disease-modifying anti-rheumatic drugs (DMARDs) are available for RA treatment, biological DMARDs (bDMARDs) offer expanding therapeutic options and good outcomes in patients with RA who do not have a sufficient response to conventional synthetic DMARDs. However, high costs of bDMARDs have limited patient access to optimised disease management and increased the cost burden for healthcare systems. The advent of biosimilars led to significant cost savings driven by price competition among the reference products, which could be beneficial for healthcare systems. Healthcare provider (HCP)–patient communication and informed shared decision-making are crucial to prevent the occurrence of a nocebo effect, which results from negative perceptions that patients may have and could lead to less effective outcomes. Research has demonstrated that effective communication between HCPs and patients utilising positive framing can improve acceptance by patients to be initiated on or switched to a biosimilar and can help to integrate biosimilars into routine clinical practice to maximise benefits for patients with RA.

Biosimilar Uptake: The Importance of Healthcare Provider Education

From peptide hormones to monoclonal antibodies, advances in biotherapeutic medicines, or biologics, have brought incalculable benefits to patients, especially for conditions where previous classes of therapy were ineffective or non-existent. At the same time, the development of biologics has been accompanied by questions of access and cost. The advent of biosimilars, molecules highly similar to their reference biologics, has offered the promise of ameliorating cost and access challenges. However, issues regarding biosimilar uptake remain. Multiple factors impact the utilization of biosimilars by healthcare providers and perhaps the best recognized of these is education. This paper discusses the importance of education to biosimilar adoption and lists action-items that various stakeholders in healthcare can adopt to improve the overall understanding of this important class of therapeutics.

Biosimilars in chronic inflammatory diseases: facts and remaining questions 5 years after their introduction in Europe

INTRODUCTION

Five years after the launch of the first infliximab biosimilar, biologics have found their place in the treatment of chronic inflammatory conditions, but there are remaining questions. This is a review of the introduction of antibody biosimilars in Europe; the reasons for their success and how biosimilar hesitancy was quailed.

AREAS COVERED

We provide an overview of the concepts of biosimilarity, extrapolation, and interchangeability, using examples in rheumatology and gastroenterology for illustration. A review of the evidence collected from switching studies using robust designs is included. Remaining questions such as 'inter-switching' are also discussed.

EXPERT OPINION

Biosimilars have democratized access to powerful medicines. Efficacy and safety studies provided reassuring data, but knowledge gaps persist. The availability of so-called 'bio-betters' might open new avenues and change clinical practice.

A Systematic Review on Infliximab Biosimilar SB2: From Pre-Clinical Data to Real-World Evidence

INTRODUCTION

The infliximab biosimilar SB2 was approved in the EU (2016, Flixabi®) and the US (2017, Renflexis®) for the same indications as the reference product (Remicade®) based on a robust analytical and clinical data package.

AREAS COVERED

This systematic literature review summarizes available analytical and clinical data on SB2, including randomized controlled clinical trials and real-world evidence studies. Overall, 184 articles and congress abstracts were identified (excluding duplicates), whereof 5 reports on analytical data, four reports on two randomized controlled trials and 13 reports of real-world evidence studies were included.

EXPERT OPINION

The available analytical and clinical data support the equivalence of SB2 to the reference product across approved indications. This is further supported by emerging real-world evidence, particularly in extrapolated indications such as inflammatory bowel disease for both infliximab-naïve patients and patients already established on infliximab switching to SB2. Switching from originator or biosimilar infliximab to SB2 including both single and multiple switches was not associated with an increased risk of loss of treatment response or any safety or immunogenicity concerns. Overall, the approved infliximab biosimilar SB2 is safe and effective in clinical practice across licensed indications.

The global landscape on interchangeability of biosimilars

INTRODUCTION

Biosimilars hold the potential to be an integral healthcare component that can significantly improve affordability and thereby accessibility of the otherwise expensive biotherapeutic products. Regulators, payors, and policymakers, each have a major role to play in successful adoption of biosimilars. One of the issues that has been a point of frequent discussion is that of interchangeability of biosimilars.

AREAS COVERED

This article aims to review the position that the major regulatory bodies have taken on interchangeability of biosimilars. Key issues that remain are also discussed. Adalimumab and etanercept have been chosen as real-world case studies to demonstrate interchangeability considerations. The need for gaining global harmonization on interchangeability is highlighted.

EXPERT OPINION

A global harmonization on the interchangeability can likely accelerate biosimilar adoption and result in better accessibility to biologics. Experience gained with real-world studies supports switching to biosimilars from originators however post-marketing pharmacovigilance should be in place to assess the risk-benefit profile of biosimilars in the long run.

The Automatic Substitution of Biosimilars: Definitions of Interchangeability are not Interchangeable

In the USA, an interchangeability designation provides biosimilar sponsors with a pathway for achieving what is standard for small-molecule generics: pharmacy-level auto-substitution for an innovator. No other major health authority links interchangeability to automatic substitution, as all require the involvement of the prescriber or patient in a medication change. This editorial considers the clinical impact and practicality of auto-substitution. First, interchangeability is linked to non-medical switching (NMS), the practice of switching treatment in patients with stable disease for non-clinical reasons. NMS may generate negative sentiment in those unwilling or reluctant to switch, which can adversely impact treatment outcomes (i.e., nocebo effect). Indeed, in real-world studies of tumor necrosis factor inhibitors, discontinuation rates have been shown to be higher in patients switched to biosimilars for non-medical reasons than in historical cohorts maintained on innovators. Second, interchangeability may impede pharmacovigilance and traceability, as not all jurisdictions require innovators and biosimilars to have distinct biologic names. Third, an interchangeability designation from the US Food and Drug Administration only permits a biosimilar to be automatically substituted for its innovator, not other biosimilars (if available). Pharmacist education would be needed to avoid off-label, automatic substitution among biosimilars of a single innovator. Last, once granted, an interchangeability designation exists in perpetuity under current US federal law. However, the supply chains of innovators and biosimilars are maintained independently, with no requirement for reconfirmation of biosimilarity or interchangeability. We feel that additional guidance is needed for the auto-substitution of biosimilars and innovators to become a reality.

Interchangeability of Biosimilars: What Level of Clinical Evidence is Needed to Support the Interchangeability Designation in the United States?

A biosimilar is a biologic drug that is "highly similar to a reference (originator) product, with no clinically meaningful differences between the two products in safety, purity, and potency". Regulatory approval of a biosimilar is based on analytical, structural, and functional comparisons with the reference product, comparative nonclinical (in vivo) studies, clinical pharmacokinetics and/or pharmacodynamics, and immunogenicity. In addition, comparative clinical efficacy and safety assessments are usually conducted and, taken together, comprise the "totality of the evidence" supporting biosimilarity. For a biosimilar to meet the additional designation of interchangeability in the United States (US), the applicant must demonstrate that the biological drug can be expected to produce the "same clinical result as the reference product in any given patient" and "if the biological drug is administered more than once to an individual, the risk in terms of safety or diminished efficacy of alternating or switching between the use of the biological drug and the reference product is no greater than the risk of using the reference product without such alternation or switch". The challenges faced in conducting clinical studies to support a designation of interchangeability, as defined in the final interchangeability guidance from the US Food and Drug Administration, are considered. Potential alternative approaches to generating adequate and sufficient clinical data to support a designation of interchangeability are also presented.

Safety of switching between rituximab biosimilars in onco-hematology

Comparable clinical efficacy and safety of the reference rituximab (MABTHERA) and its biosimilars has been established in randomized trials. However, safety concerns are often raised when switching from reference to biosimilar products and between different biosimilars. In this prospective observational study we aimed at evaluating the safety of switching between reference and biosimilar rituximab (TRUXIMA and RIXATHON) at Trento General Hospital (Italy). All patients (n = 83) with Non Hodgkin’s Lymphoma (NHL, n = 72) and Chronic Lymphocytic Leukemia (CLL, n = 11) who received rituximab between March 2018 and March 2019 were asked to take part in the study. In 2017 and 2018 two tenders were carried out and two different biosimilars became available in the hospital, these were used sequentially. Thus, patients with or without previous treatments with the originator rituximab either received a biosimilar or were switched between different biosimilars. The incidence of adverse events in these groups of patients is described. The study population received 465 rituximab infusions and all received biosimilars. Fifty patients (60%) experienced at least one switch between different biosimilars or between rituximab originator and biosimilar, whereas 33 (40%) received one of the two biosimilars and one patient received reference rituximab. Adverse events (n = 146) were reported in 71 patients (84.5%). Treatment-related grade 3–4 events were reported in 5 patients (5.9%), whereas grade 1 rituximab related infusion events were observed in 6 patients (7.1%). No safety signal emerged in association with the use of a specific biosimilar nor with the practice of switching. Adverse events were similar, in terms of seriousness and frequency, to those described in the literature, providing further support to the clinical safety of rituximab biosimilars.