Safety of switching between rituximab biosimilars in onco-hematology

Occlusive Vasculitis Following Intravitreal Rituximab Injection for Primary Vitreoretinal Lymphoma

PURPOSE

We report three cases of occlusive vasculitis following intravitreal rituximab therapy for biopsy-proven primary vitreoretinal lymphoma (PVRL), one of which was following an injection of the biosimilar Riabni (rituximab-arrx, AmGen) and two of which were following an injection of Rituxan (rituximab, Genentech).

METHODS

Case series.

RESULTS

Three cases of occlusive vasculitis confirmed with fluorescein angiography are reported 5 days, 8 days, and 3.5 weeks following intravitreal injection of rituximab. The initial vision was poor (20/500, 20/150, and light perception), but vision recovered to baseline in two cases, and remained poor in the case of combined artery and vein occlusion.

CONCLUSION

Occlusive vasculitis is a rarely reported but potential complication of intravitreal rituximab therapy in patients who have been previously treated with the agent and may have delayed onset. A low threshold for fluorescein angiography as a diagnostic test for post-injection vision loss and prompt treatment with topical and/or oral steroids should be considered.

Additional Data in Expanded Patient Populations and New Indications Support the Practice of Biosimilar-to-Biosimilar Switching

As of 31 December, 2023, 31 observational studies have been published, including a total of 6081 patients who underwent a switch from one biosimilar to another biosimilar of the same reference biologic. Most studies evaluated infliximab, while a smaller number evaluated adalimumab, rituximab or etanercept. Indications studied now include sarcoidosis, as well as the indications previously reported of rheumatoid arthritis, psoriatic arthritis, axial spondyloarthritis/ankylosing spondylitis and inflammatory bowel disease (Crohn's disease and ulcerative colitis). This updated data set includes eight additional studies and 2386 more patients compared with those included in an earlier systematic review of biosimilar-to-biosimilar switching. In addition, since the earlier systematic review was published in 2022, the European Medicines Agency has stated that reference-to-biosimilar and biosimilar-to-biosimilar switching in the European Union is safe and efficacy remains unchanged after switching. Furthermore, following a review of the available evidence, the US Food and Drug Administration has confirmed that initial safety and immunogenicity concerns related to biosimilar switching are unfounded and that no differences are observed in efficacy, safety or immunogenicity following one or more switches. The availability of this new efficacy and safety data together with the supportive statements from the European Medicines Agency and the Food and Drug Administration re-confirm the conclusion that as a scientific matter, biosimilar-to-biosimilar switching is an effective clinical practice, with no new safety concerns. Any suggestions to the contrary are not supported by the evidence.

The comparison of safety and cost between reference drug of rituximab and its biosimilar Riximyo in lymphoproliferative disorders and other hematological diseases. Single center experience

Rituximab, anti-CD20 monoclonal antibody, has broad clinical application. The aim of this study is to compare the safety and cost of the original reference rituximab (MabThera) and its biosimilar (Riximyo). This retrospective analysis of 262 patients receiving Riximyo in the Department of Hematology of Wroclaw Medical University in Poland from the period of 1 October 2020 to 21 June 2021 focused on infusion-related reactions (IRRs), which occurred in 4,96% of patients (N = 13). 109 patients (41,6%) had previously been treated with the reference drug and 2 IRRs were reported after switching therapy. During the study period, after biosimilar introduction, the cost of rituximab decreased by 41%. Rixmyo while maintaining similar safety profile is much more cost-effective.

Biosimilars: From Production to Patient

Biologic drugs are large, complex molecules produced through biotechnology. A biosimilar is a biologic product that is highly similar to an already approved biologic (reference product), with no clinically meaningful differences in purity, safety, or efficacy; as such, a biosimilar does not need to undergo the same level of study in a clinical trial program as the original reference product. Due to the potential impact of biosimilars on patient access and health care systems, the US Food and Drug Administration introduced an abbreviated pathway for approving biosimilars (351[k]) in 2009. There is strong evidence that switching from a reference product to a biosimilar does not reduce treatment effectiveness or increase the risk of adverse events. Biosimilars may reduce costs and increase patient access to biologic therapies. Biosimilar use in the United States has increased, as have the associated biosimilar cost savings, which are expected to reach $104 billion between 2020 and 2024. Yet, a need remains for increased knowledge among health care professionals and patients. Prescriber confidence is key to patient acceptance of biosimilars and minimizing the incidence of the nocebo effect. Infusion nurses are well positioned to help educate patients and to improve clinical outcomes across a range of diseases.

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.

Switching from One Biosimilar to Another Biosimilar of the Same Reference Biologic: A Systematic Review of Studies

BACKGROUND

Multiple switches (transitions) between biosimilars of the same reference biologic are now a reality, and they are expected to become more common in the future as more biosimilars enter the market. Switching between two biosimilars of the same reference biologic is generally driven by affordability, formulary requirements, or the relocation/travel of the patient. Evidence of whether switching between biosimilars of the same reference biologic provides similar safety and efficacy profiles is reviewed here.

METHODS

A systematic search was undertaken using electronic databases (to December 2021): Biosis, Embase, MEDLINE, and EBM Reviews/Cochrane Database of Systematic Reviews via Ovid. Publications were evaluated for effectiveness and/or safety data linked to switching from one biosimilar to another.

RESULTS

The systematic search yielded 982 citations. After eliminating duplicates, 626 citations remained for the initial title/abstract screening phase. Following the initial screening, 240 records were chosen; more thorough examination yielded 35 citations. After comprehensive screening and expert advice, 23 studies were selected, of which 13 were published in peer-reviewed journals; the remainder have been published as abstracts. Overall, 3657 patients were included in these studies. All studies were observational in nature; no randomized clinical trials were identified. The studies were heterogeneous in size, design, and endpoints. Across the studies, data are provided on safety, effectiveness, immunogenicity, pharmacokinetics, patient retention, patient and physician perceptions, and drug-use patterns. The majority of studies examined switches between biosimilar infliximabs, although switches between biosimilar adalimumabs, etanercepts, and rituximabs were also identified. Two use-pattern studies and one case report were also detected and are discussed.

CONCLUSION

Within the limitations of this systematic review, available data suggests that biosimilar-to-biosimilar switching is a safe and effective clinical practice, although it is not covered by current health authority regulations or guidance. No reduction in effectiveness or increase in adverse events was detected in biosimilar-to-biosimilar switching studies conducted to date.

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.

Biosimilar Use in Breast Cancer Treatment: A National Survey of Brazilian Oncologists' Opinions, Practices, and Concerns

PURPOSE

Breast cancer is the most common malignancy in Brazilian women, with 66,280 new cases in 2020 (with 20% overexpressing human epidermal growth factor receptor 2 [HER2]). The trastuzumab biosimilar was the first oncology biosimilar approved in Brazil for HER2-positive breast cancer treatment. This study aimed to assess the current level of knowledge of biosimilars, comfort of use, extrapolation indications, and switching of practices among oncologists in Brazil.

METHODS

A 24-question survey was developed using an online platform that sought information regarding responders' characteristics and use of biosimilars. The survey analyzed the basic knowledge of biosimilars, trastuzumab biosimilars, level of comfort with extrapolation, switching treatment regimens, and opinions concerning the cost of HER2-positive breast cancer therapy. Data were collected between July and September 2019 and included 144 oncologists from five Brazilian regions.

RESULTS

In total, 95% of respondents could identify the most appropriate definition of biosimilars and 96% felt comfortable prescribing trastuzumab biosimilars. Although 63% of respondents would use the biosimilar in all settings wherein the reference biologic was approved, 35% would use the biosimilar for cases involving metastatic disease. Although 82% of oncologists were in favor of switching from a reference biologic to a biosimilar, 18% would avoid switching regimens. The lack of studies detailing switching to other regimens and the correct timing to switch was the major concern. The cost of HER2 therapy was a significant concern for most oncologists.

CONCLUSION

Oncologists demonstrated a high level of knowledge of biosimilars and encouraging levels of prescriber use; however, extrapolation and switching treatment regimens are barriers to the effective use of biosimilars in cancer treatment. Efforts should be concentrated on strategies involving medical education programs on biosimilars.