The performance of Remicade®-optimized quantification assays in the assessment of Flixabi® levels

Surface plasmon resonance assays for the therapeutic drug monitoring of infliximab indicate clinical relevance of anti-infliximab antibody binding properties

OBJECTIVES

The therapeutic antibody infliximab (IFX) has improved the life quality of numerous autoinflammatory disease patients. However, IFX can trigger the generation of anti-drug antibodies (ADA), whose optimal evaluation and management are currently subject of controversial discussions. We present two novel surface plasmon resonance (SPR) biosensor assays for therapeutic drug monitoring of IFX and characterization of ADA and investigated the diagnostic value of ADA binding properties.

METHODS

IFX and ADA were quantified via developed SPR biosensor assays (IFXmon and ADAmon, respectively) and diagnostics-approved ELISA in sera from inflammatory bowel disease patients. Pre-analytic ADA enrichment with magnetic beads enabled analytical drug tolerance of the ADAmon assay. The dissociation ratio (DissR) as an index for ADA:IFX binding stability was calculated from the SPR sensorgrams of ADA quantification runs.

RESULTS

IFX levels determined by IFXmon assay and ELISA showed high agreement, whereas ADA quantification concordance between ADAmon assay and ELISA was poor. In patients, DissR was predominantly constant over time and differed significantly between therapy outcomes. A DissR cut-off of 1.524 indicated undetectable IFX levels with 71.4% sensitivity and 88.9% specificity. Additionally, the SPR reference surface was exploited as serum-individual negative control to check result plausibility within multi-sample run sequences.

CONCLUSIONS

Overall, both SPR biosensor assays exhibited reliable quantitative performance with accuracies superior to their ELISA counterparts and precision inferior to ELISA only for ADAmon. DissR presented itself as promising ADA binding parameter and could contribute to both earlier and more tailored therapeutic decisions.

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.

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.

Infliximab use in the Netherlands: Uptake and characteristics of originator and biosimilars over time

AIMS

The objective of this retrospective cohort study was to provide an overview of the utilization of originator and biosimilar infliximab in the Netherlands.

METHODS

All infliximab dispensings were selected from the PHARMO In-patient Pharmacy Database from 2002-2018. Descriptive analyses were performed in order to characterise initiators and to describe switching patterns over time.

RESULTS

Overall, 3840 patients with 61 274 infliximab dispensings were identified. 2496 patients initiated an originator infliximab and 777 patients initiated a biosimilar infliximab. Overall, 57% of the patients was female and mean age was 43.2 years. Both originators and biosimilars were mostly prescribed by gastroenterologists, followed by internists and rheumatologists. After market authorisation of the first biosimilar, the proportion of new patients initiating the biosimilar increased from 39% in 2015 to 91% in 2018. Out of 704 patients eligible for switching 34% switched. Among switchers, the proportion of females was 60% and mean age at index was 45.1 years. Among nonswitchers, 55% were female and mean age was 39.8 years. The median time to switch was 1.7 years and switchers were most frequently initiated on infliximab by a rheumatologist (42%), while nonswitchers were most frequently initiated by a gastroenterologist (42%).

CONCLUSION

The results of this large population-based cohort show an increase in biosimilar initiation in daily clinical practice. The number of switchers remains relatively low as nonmedical switch is not encouraged in the Netherlands.

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.

Switching to an Infliximab Biosimilar Was Safe and Effective in Dutch Sarcoidosis Patients

The effect of switching from originator infliximab to biosimilar infliximab in patients with sarcoidosis is unknown. The objective of this study is to investigate the effect of switching from Remicade^® or Inflectra^® to Flixabi^® in patients with severe refractory sarcoidosis. This single center retrospective cohort study was performed at St Antonius Hospital Nieuwegein, The Netherlands. All patients diagnosed with severe refractory sarcoidosis receiving Remicade^® or Inflectra^® switched to Flixabi^®. The primary outcome was infliximab discontinuation within 6 months of switching. Secondary endpoints included adverse events and loss of clinical, functional, or inflammatory response. Out of 86 patients who switched to Flixabi^®, 79 patients had complete data. None of the 79 patients discontinued infliximab during the first 6 months after switching. Five patients reported an adverse event related to Flixabi^® treatment. We found no change from baseline in FVC, FEV1, DLCOc, 6MWT, and infliximab trough levels 26 weeks after switching. An improvement in physical functioning of 7.3 ± 13.4 points (p = 0.002) with RAND/SF36 and in biomarker sIL-2R (−475.58 ± 1452.39; p = 0.005) was observed. Switching from originator infliximab Remicade^® or biosimilar infliximab Inflectra^® to biosimilar infliximab Flixabi^® did not result in treatment discontinuation or loss of clinical/functional/inflammatory remission.

Assays used to assess biosimilarity of therapies for inflammatory bowel disease

Introduction: Biological drugs have revolutionized the treatment of various medical conditions. Recently, upon expiration of patents of a few biological agents, biosimilars are being rapidly developed as an affordable substitute for more expensive biologic drugs, which may serve as a therapeutic alternative for biologics reference medical product (RMP). Prior to approval for use of the biosimilar drug for treatment of RMP indications, a process involving several different assays is required, in which the biosimilar must prove to posses no meaningful differences from an existing approved RMP in terms of purity, safety and potency.Areas covered: This report describes the different assays which are used to assess biosimilar drugs using CT-P13 infliximab biosimilar as a case-in-point. It covers the assays of physicochemical characterization, biological activity, and immunogenicity and examines their rational along with methodological and conceptual caveats clinicians should be cognizant of.Expert opinion: The approval of a biosimilar is a complex process that requires several assays, specifically tailored to the characteristics of the RMP. Determining the required assays and the allowable margin of confidence are of great importance but are not sufficient in order to prove that the biosimilar is indeed not inferior in its clinical potency and safety to the RMP.

SB5 shows cross-immunogenicity to adalimumab but not infliximab: results in patients with inflammatory bowel disease or rheumatoid arthritis

BACKGROUND

The primary objective of this study was to analyze the cross-reactivity of antidrug antibodies to reference adalimumab (ADL) and SB5 (adalimumab biosimilar) in patients with inflammatory bowel disease (IBD) or rheumatoid arthritis (RA).

METHODS

Sera from patients with IBD and RA with or without antibodies to adalimumab (ATA+ or ATA-, respectively) were tested for cross-reactivity with SB5 and ADL. Functional inhibition of tumor necrosis factor-α binding was measured. Sera from patients with antibodies to reference infliximab (ATI+) were examined for cross-reactivity to SB5. Sera were tested by enzyme-linked immunosorbent assay.

RESULTS

All 30 anti-ADL ATA+ sera from patients with IBD and all 4 anti-SB5 ATA+ sera from patients with RA were cross-reactive with ADL and SB5 (range of mean concentrations: IBD, 20.99-21.31 μg/ml; RA, 16.46-17.48 μg/ml). In general, there was no significant difference between mean ATA titers. A strong correlation was detected in all ATA+ samples (rho = 0.997 to >0.999; p < 0.001 each). However, ATA- sera were not reactive to either ADL or SB5. anti-ADL ATA+ sera similarly neutralized functional activity of ADL and SB5; no functional inhibition was observed with ATA- sera. ATI+ sera did not cross-react with SB5.

CONCLUSIONS

ADL and SB5 show cross-immunogenicity in sera from patients with IBD or RA, supporting shared immune-dominant epitopes. ATI+ sera did not cross-react with SB5, suggesting different immunogenic epitopes between infliximab and SB5.