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

Effect of treatment with original or biosimilar adalimumab on SARS-CoV2 vaccination antibody titers

The technological process of production of biosimilars determines the degree of biosimilarity to the original biological drug. In particular, the focus is on the similarity of immunogenic responses. The primary endpoint of our retrospective study was to find the differences in SARS-CoV-2 antibody amount between patients treated with original adalimumab and biosimilar adalimumab MSB11022 (Idacio) and the differences in the SARS-CoV-2 antibody amount between patients treated with and without biological treatment. We collected the gender, autoimmune disease type, age, and treatment data of the patients in the outpatient clinic MEDICAL PLUS, s.r.o., Uherske Hradiste. These patients suffer from autoimmune rheumatic diseases. All patients received the mRNA vaccine (Pfizer/BioNTech - BNT162b2), with a 21-day (interquartile range, 21-24) gap between the two vaccinations. Patients receiving adalimumab were able to develop cellular immune responses after the second vaccination dose, as well as the individuals without adalimumab. In the period of 6-23 weeks after the second vaccination dose (D63 - D182), the SARS-CoV-2 antibody levels did not change significantly in the patients receiving the original adalimumab, while in the patients receiving biosimilar adalimumab a significant decrease was revealed. A statistically significant difference in the SARS-CoV-2 antibody amount between the patients without biological treatment (median: 504.3 U/mL) and with biological treatment (Original and Biosimilar - median: 47.2 and 28.2 U/mL, respectively) was confirmed on day 182. According to our observation, the effect of the treatment type on the increase/decrease of antibodies over time is dominant, while the impact of other variables (gender, methotrexate treatment, autoimmune disease type, and age) was confirmed as insignificant or minor.

A Retrospective Analysis of the Potential Impact of Differences in Aggregates on Clinical Immunogenicity of Biosimilars and their Reference Products

Aggregates, in particular high molecular weight species (HMWs), have been linked to increased immunogenicity. The current understanding on the impact of HMWs is mainly based on in vitro and nonclinical studies and there are only limited data available associating differences in HMWs in marketed monoclonal antibodies (mAbs) to clinical outcomes. Biosimilars offer a unique opportunity to study the potential association between quality parameters and clinical outcomes. We performed a retrospective evaluation to investigate the association between HMW content and reported antidrug-antibody (ADA) incidence in 30 full-length biosimilar mAbs approved in the European Union and the United States. Information for HMW content and ADA incidence were collected from publicly available sources. Differences in HMW content between biosimilars and their reference products (RPs) ranged from -0.75 to 1.65% with slightly higher differences observed in antineoplastic products as compared with immunosuppressant products. The difference in the ADA incidence between the RP and the biosimilar for the programs studied ranged from -11.0 to 18.5%. No association was observed between differences in HMW content and reported ADA incidence, in neither phase I nor phase III studies. Our results show that the limited differences in the content of HMWs between marketed biosimilars and reference mAbs were not associated with differences in reported immunogenicity, determined as incidence of ADAs and neutralizing ADAs in comparative clinical studies.

Future Evolution of Biosimilar Development by Application of Current Science and Available Evidence: The Developer's Perspective

Biosimilars have been available in the USA for over a decade, and in Europe for almost two decades. In that time, biosimilars have become established in the treatment landscape for a wide range of diseases, facilitating patient access and affordability of healthcare. However, patients can still struggle to access biological therapies in some markets. There is a need to streamline the process of developing biosimilars without compromising their quality, safety, or efficacy. This opinion piece considers the efficiencies that could be achieved within the biosimilar approval process. In clinical trials for biosimilars, clinical efficacy endpoints have been shown to be less sensitive measures of biosimilarity than biochemical, biophysical, and biological functional assays. Additional clinical efficacy studies comparing potential biosimilars and reference products do not add information that is useful for regulatory purposes. Large clinical studies of biosimilars with immunogenicity endpoints are of limited value, given the quality control processes in place for all biologics, including biosimilars. The expectation for multiple-switch studies for US interchangeability designation should be reconsidered immediately, and the category should be eliminated in the future. As biosimilars are typically approved globally based on a single set of clinical trials, and all subsequent manufacturing changes are already carefully monitored by regulatory authorities, comparative pharmacokinetic testing of EU and US reference products is unnecessary. Manufacturers and regulators could take greater advantage of existing real-world evidence. Streamlining biosimilar development would enable biosimilar development of more and a wider variety of biological drugs, accelerating biosimilar development without impacting patient safety or effectiveness.

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.

Anti-Drug Antibodies in the Biological Therapy of Autoimmune Rheumatic Diseases

Autoimmune rheumatic diseases are a cluster of heterogeneous disorders that share some clinical symptoms such as pain, tissue damage, immune deregulation, and the presence of inflammatory mediators. Biologic disease-modifying antirheumatic drugs are some of the most effective treatments for rheumatic diseases. However, their molecular and pharmacological complexity makes them potentially immunogenic and capable of inducing the development of anti-drug antibodies. TNF inhibitors appear to be the main contributors to immunogenicity because they are widely used, especially in rheumatoid arthritis. Immunogenicity response on these treatments is crucial since the appearance of ADAs has consequences in terms of safety and efficacy. Therefore, this review proposes an overview of the immunogenicity of biological agents used in autoimmune rheumatic diseases highlighting the prevalence of anti-drug antibodies.

Switching from adalimumab originator to biosimilar: a 3-year retrospective cohort analysis

Our three year retrospective cohort study demonstrated that the vast majority of patients tolerated the switch from adalimumab originator to adalimumab biosimilar, with a 19% switchback rate. All patients who switched back to originator from biosimilar recovered from loss of efficiency and reported adverse events.

Physicians therefore should be confident in switching patients with well controlled psoriasis to adalimumab biosimilars.

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.

Assessing Immunogenicity of Biologic Drugs in Inflammatory Joint Diseases: Progress Towards Personalized Medicine

Biologic drugs have greatly improved treatment outcomes of inflammatory joint diseases, but a substantial proportion of patients either do not respond to treatment or lose response over time. Drug immunogenicity, manifested as the formation of anti-drug antibodies (ADAb), constitute a significant clinical problem. Anti-drug antibodies influence the pharmacokinetics of the drug, are associated with reduced clinical efficacy, and an increased risk of adverse events such as infusion reactions. The prevalence of ADAb differs among drugs and diseases, and the detection of ADAb also depends on the assay format. Most data exist for the tumor necrosis factor-alpha inhibitors infliximab and adalimumab, with a frequency of ADAb that ranges from 10 to 60% across studies. Measurement of ADAb and serum drug concentrations, therapeutic drug monitoring, has been suggested as a strategy to optimize therapy with biologic drugs. Although the recent randomized clinical Norwegian Drug Monitoring (NOR-DRUM) trials show promise towards a personalized medicine prescribing approach by therapeutic drug monitoring, several challenges remain. A plethora of assay formats, with widely differing properties, is currently used for measuring ADAb. Comparing results between different assays and laboratories is difficult, which complicates the development of cut-offs necessary for guidelines and the implementation of ADAb measurements in clinical practice. With the possible exception of infliximab, limited data on clinical relevance and cost effectiveness exist to support therapeutic drug monitoring as a routine clinical strategy to monitor biologic drugs in inflammatory joint diseases. The aim of this review is to provide an overview of the characteristics and prevalence of ADAb, predisposing factors to ADAb formation, commonly used assessment methods, clinical consequences of ADAb, and the potential implications of ADAb assessments for everyday treatment of inflammatory joint diseases.

Switching Between Adalimumab Reference Product and BI 695501 in Patients with Chronic Plaque Psoriasis (VOLTAIRE-X): A Randomized Controlled Trial

Background

BI 695501 is an FDA-approved biosimilar to adalimumab reference product (RP). VOLTAIRE-X was a randomized clinical trial to assess outcomes with a biosimilar monoclonal antibody in line with the FDA requirements for designation as an ‘interchangeable’ biosimilar.

Objective

The aim of this study was to assess whether multiple switches between adalimumab RP and BI 695501 lead to equivalent pharmacokinetics and a similar safety and immunogenicity profile compared with continuous adalimumab RP.

Methods

We conducted a phase III, double-blind, randomized controlled trial between July 19, 2017, and April 16, 2019. There were 49 investigational sites across Europe and North America. Of 323 screened patients with moderate-to-severe chronic plaque psoriasis, 259 were treated with adalimumab RP during the run-in period. Of these, 118 and 120 were randomized to the continuous or switching arms, respectively. Interventions consisted of a run-in period with adalimumab RP 80 mg subcutaneously (SC) on Day 1, then 40 mg SC every other week (EOW) Weeks 2–12. Patients were then randomized to receive adalimumab RP 40 mg EOW Weeks 14–48 (continuous arm) or BI 695501 40 mg Weeks 14 and 16, adalimumab RP 40 mg Weeks 18 and 20, and BI 695501 40 mg EOW Weeks 22 to 48 (switching arm); all interventions were given SC. Primary endpoints were pharmacokinetics parameters, area under the plasma concentration–time curve (AUC_τ,30–32) and maximum observed drug plasma concentration (C_max,30–32), measured after the third switch during the Week 30–32 dosing interval.

Results

238 patients (mean [standard deviation] age 44.9 [13.8]; 66.0% male) were treated in the switching (n = 118) or continuous arms (n = 120). Adjusted mean C_max,30–32 was 7.08 and 7.00 μg/mL in the switching and continuous treatment arms, respectively; adjusted mean AUC_τ,30–32 was 2025.8 and 1925.9 μg h/mL. Point estimate for mean ratio for AUC_τ,30–32 was 105.2% (90.2% confidence interval [CI] 96.6–114.6), and 101.1% (90.2% CI 93.3–109.7) for C_max,30–32. Both CIs were within a predefined bioequivalence range of 80.0–125.0%. Treatment-emergent adverse events led to discontinuation in 0.8% and 1.7% of patients in the switching and continuous treatment arms, and Psoriasis Area and Severity Index (PASI) scores were highly similar in the two arms across the entire trial period.

Conclusions

Pharmacokinetic equivalence was demonstrated, with highly similar efficacy and immunogenicity, and comparable safety observed in patients with chronic plaque psoriasis who received either adalimumab RP continuously or who switched between adalimumab RP and BI 695501.

Trial Registration

ClinicalTrials.gov: NCT03210259 (registered July 2017); Eudract.ema.europa.eu: 2016-002254-20.

Video abstract

UNC13B Promote Arsenic Trioxide Resistance in Chronic Lymphoid Leukemia Through Mitochondria Quality Control

In clinical practice, arsenic trioxide can be used to treat a subset of R/R CML patients, but resistance tends to reappear quickly. We designed an experiment to study arsenic trioxide resistance in K-562 cells. Previously, we identified the UNC13B gene as potentially responsible for arsenic trioxide resistance in K-562 cells via gene chip screening followed by high-content screening. We aimed to investigate the role and mechanism of the UNC13B gene in K-562 cells, an arsenic trioxide-resistant chronic myeloid leukemia cell line. In vitro lentiviral vector-mediated UNC13B siRNA transfection was performed on K-562 cells. The roles of UNC13B in cell proliferation, apoptosis and cell cycle pathways, and colony formation were analyzed by CCK-8 assay, fluorescence-activated cell sorting, and soft agar culture, respectively. Gene chip screening was used to define the possible downstream pathways of UNC13B. Western blot was performed to further validate the possible genes mediated by UNC13B for arsenic trioxide resistance in patients with chronic myeloid leukemia. UNC13B downregulation significantly inhibited growth, promoted apoptosis, decreased colony formation, reduced the duration of the G1 phase, and increased the duration of the S phase of K-562 cells. Western blot results confirmed that UNC13B may modulate the apoptosis and proliferation of arsenic trioxide-resistant chronic myeloid leukemia cells through the mediation of MAP3K7, CDK4, and PINK1. UNC13B is a potential therapeutic target for patients with arsenic trioxide-resistant chronic myeloid leukemia.

Enhancing the Response Rate to Recombinant Uricases in Patients with Gout

Refractory, or uncontrolled, gout is a chronic, progressive, inflammatory arthropathy resulting from continued urate deposition after failed attempts to lower serum uric acid below the therapeutic threshold with oral urate-lowering therapies such as allopurinol and febuxostat. Recombinant uricase is increasingly being used to treat refractory gout; however, the immunogenicity of uricase-based therapies has limited the use of these biologic therapies. Antidrug antibodies against biologic therapies, including uricase and PEGylated uricase, can lead to loss of urate-lowering response, increased risk of infusion reactions, and subsequent treatment failure. However, co-therapy with an immunomodulator can attenuate antidrug antibody development, potentially increasing the likelihood of sustained urate lowering, therapy course completion, and successful treatment outcomes. This review summarizes evidence surrounding the use of immunomodulation as co-therapy with recombinant uricases.

Switching from Adalimumab Originator to Biosimilar: Clinical Experience in Patients with Hidradenitis Suppurativa

Adalimumab is currently the only biological medicine approved by the FDA for the treatment of hidradenitis suppurativa (HS). The breakout of biosimilar drugs made them more accessible due to their impact on pharmacoeconomics. However, packaging, formulation, or excipients are unique characteristics of each drug. In that way, switching from adalimumab originator to biosimilar and between biosimilars could have implications in the clinical practice. The objective of this study is to describe our clinical experience in switching from adalimumab originator to biosimilar and switching back again. A single-center retrospective cohort study was conducted that included seventeen patients with HS treated with adalimumab originator in the maintenance phase, and that achieved Hidradenitis Suppurativa Clinical Response (HiSCR), who were switched to adalimumab biosimilar for no medical reasons. The reason for the change was to improve pharmacoeconomic efficiency, following our hospital policies on biologics. Median duration with adalimumab originator treatment before switching was 48 weeks. After switching, 41.2% of patients maintained HiSCR response without additional issues, while 58.8% (10/17) reported problems after the change. Switching from adalimumab originator to biosimilar in well-controlled patients could imply problems in efficacy and adherence. Switching back to adalimumab originator appears to solve most of the problems, but some patients can lose confidence in the drug and discontinue it. It would be worthwhile to evaluate the benefit–risk ratio individually when switching an HS patient to adalimumab biosimilar.

Expert Opinion on Pegloticase with Concomitant Immunomodulatory Therapy in the Treatment of Uncontrolled Gout to Improve Efficacy, Safety, and Durability of Response

Purpose of Review

Gout is a systemic disease from which some patients develop numerous painful tophi that adversely affect quality of life and functionality. Some patients treated with oral urate-lowering therapy are unable to maintain serum urate levels below 6 mg/dL, and these patients, thus classified as having refractory or uncontrolled gout, often require therapy with pegloticase to reduce symptoms and tophaceous burden. The objective of this expert opinion review is to summarize the available evidence supporting the use of concomitant immunomodulators with pegloticase to prevent development of anti-drug antibodies (ADAs) when treating patients with uncontrolled gout.

Recent Findings

Emerging evidence suggests that adding an immunomodulator to pegloticase therapy can substantially increase response rates to double those observed in phase 3 randomized controlled trials.

Summary

The combination of immunomodulation with pegloticase should be considered in routine clinical practice to improve durability of response, efficacy, and safety among patients with uncontrolled gout who otherwise have limited therapeutic options.

Efficacy and Safety of HLX03, an Adalimumab Biosimilar, in Patients with Moderate-to-Severe Plaque Psoriasis: A Randomized, Double-Blind, Phase III Study

INTRODUCTION

Adalimumab has been used successfully in the treatment of psoriasis. The objective of the study is to compare the efficacy, safety, and immunogenicity between HLX03, an adalimumab biosimilar, and adalimumab in Chinese patients with moderate-to-severe plaque psoriasis.

METHODS

In this double-blind, active-controlled, parallel-group study, 262 patients with moderate-to-severe plaque psoriasis were randomized (1:1) to receive HLX03 or adalimumab (80 mg at week 1, 40 mg at week 2, and then 40 mg every 2 weeks) for 48 weeks. The primary endpoint was improvement in Psoriasis Area and Severity Index (PASI) score at week 16 comparing to baseline. Equivalence was demonstrated if 95% confidence interval (CI) of the between group difference fell within the equivalence margins of ± 15%. Other efficacy endpoints, safety and immunogenicity were also evaluated.

RESULTS

In the full analysis set, PASI improvements at week 16 was 83.5% (n = 131) in the HLX03 group and 82.0% (n = 130) in the adalimumab group, with a least-square-mean difference of 1.5% (95% CI - 3.9% to 6.8%). There were no significant between-group differences in all secondary efficacy analyses including proportion of patients achieving ≥ 75% improvement from baseline PASI (PASI 75), physician global assessment (PGA) 0/1 (clear or almost clear) and change in dermatology life quality index (DLQI) score. The incidences of adverse events and the proportion of patients with antidrug antibodies were also comparable between the two treatment groups.

CONCLUSION

HLX03 demonstrated equivalent efficacy, similar safety and immunogenicity to reference adalimumab, supporting its development as an alternative treatment for patients with plaque psoriasis in China.

CLINICAL TRIAL REGISTRATION

Chinadrugtrials.org.cn, CTR20171123 (November 27, 2017); ClinicalTrials.gov, NCT03316781 (October 20, 2017).

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.

Immunogenicity of Tumor Necrosis Factor Antagonists and Effect of Dose Escalation on Anti-Drug Antibodies and Serum Drug Concentrations in Inflammatory Bowel Disease

BACKGROUND

Infliximab and adalimumab concentrations are associated with important outcomes in inflammatory bowel disease (IBD). Antibodies to infliximab (ATI) and adalimumab (ATA) are associated with reduced drug concentrations and worse outcomes. Because the efficacy of dose escalation to overcome antibodies is unclear, we assessed the impact of this strategy to overcome immunogenicity in IBD.

METHODS

Infliximab and adalimumab dosing, drug, and antibody concentrations were extracted from a database of patients with IBD having specimens collected for therapeutic drug monitoring. The primary outcome compared proportions with either infliximab ≥5 μg/mL or adalimumab ≥7.5 μg/mL and undetectable antibodies between dose-escalated and non-escalated patients. Area under the receiver operating characteristic curve analyses determined antibody concentrations below which dose escalation was associated with the primary outcome.

RESULTS

The study included 63,176 patients treated with infliximab and 46,429 patients treated with adalimumab. We detected ATI and ATA in 23.6% (n = 14,900) of patients treated with infliximab and 19.6% (n = 9101) of patients treated with adalimumab. In patients with ATI, infliximab dose escalation (n = 453) yielded higher proportions achieving the primary outcome (47.5% vs 30.9%; P < 0.001), greater drug concentration increases (5.9 μg/mL vs 0.2 μg/mL; P < 0.001), and ATI reductions (4.3 U/mL vs 1.9 U/mL; P = 0.002) compared to no escalation (n = 204). An ATI threshold of 8.55 U/mL was associated with achieving the primary outcome with dose escalation (area under the curve = 0.66). For patients with ATI ≤8.55 U/mL (n = 274), higher proportions (59.1% vs 29.6%; P < 0.001) achieved the primary outcome compared with those with ATI >8.55 U/mL (n = 179). No patients treated with adalimumab achieved the primary outcome (0/390), regardless of dose escalation (n = 87).

CONCLUSION

Dose escalation increased drug concentrations and eliminated antibodies with infliximab but not adalimumab. Initial ATI ≤8.55 U/mL was associated with increased efficacy of dose escalation using this assay.

Novel methodology comparing two assay formats for the assessment of immunogenicity from clinical trial samples

Aim: We present a novel methodology to compare results between distinct immunogenicity assays, performed by two laboratories, for the same biotherapeutic. Materials & methods: Human serum pools from clinical trials were generated to provide representative immunogenicity titers. Pools were evaluated at two laboratories in a blinded fashion to assess the effect of assay format and laboratory change on clinical interpretation of immunogenicity results. Results: The laboratories validated two different assay formats and demonstrated comparable sensitivity and drug tolerance. Overall, the comparisons in assay format and laboratory ensured a comparable ability to detect treatment-emergent antidrug antibodies for a biotherapeutic. Conclusion: We have established an approach, using pooling of patient samples, that allows for the interlaboratory comparisons without creating duplicative results.

Serum fatty acid binding protein 5 (FABP5) as a potential biomarker of inflammation in psoriasis

Fatty acid binding protein 5 (FABP5) is elevated in psoriatic keratinocytes and could be involved in systemic metabolic disturbances in psoriasis. The aim of the study was to evaluate serum FABP5 in obese and non-obese psoriatic patients, to assess the relationship between FABP5 and the duration, severity of the disease, inflammatory and metabolic markers and influence of treatment with narrowband-ultraviolet B (NB-UVB). Seventy-four patients (30 treated with NB-UVB) with psoriasis were enrolled in the study. The serum concentrations of FABP5 were measured using Human FABP5 Enzyme-Linked Immunosorbent Assay kit. Serum fatty acids were measured by gas-liquid chromatography. Serum FABP5 levels in psoriatic patients were higher versus control group (P < 0.001). FABP5 in patients with PASI > 20 was higher compared to the mild group (PASI < 10) (P < 0.001) and serum FABP5 correlated positively with PASI score (r = 0.41, P < 0.001). There was also positive correlation between FABP5 and basic inflammation indices. Decrease of PASI after NB-UVB treatment (P < 0.001) was observed and accompanied by decrease of the serum FABP5 (P = 0.007). FABP5 is a potential marker of psoriasis, its severity and clinical outcome after therapy with NB-UVB. FABP5 may reflect metabolic disturbances in psoriatic patients.

Bioanalysis in the Age of New Drug Modalities

In the absence of regulatory guidelines for the bioanalysis of new drug modalities, many of which contain multiple functional domains, bioanalytical strategies have been carefully designed to characterize the intact drug and each functional domain in terms of quantity, functionality, biotransformation, and immunogenicity. The present review focuses on the bioanalytical challenges and considerations for RNA-based drugs, bispecific antibodies and multi-domain protein therapeutics, prodrugs, gene and cell therapies, and fusion proteins. Methods ranging from the conventional ligand binding assays and liquid chromatography-mass spectrometry assays to quantitative polymerase chain reaction or flow cytometry often used for oligonucleotides and cell and gene therapies are discussed. Best practices for method selection and validation are proposed as well as a future perspective to address the bioanalytical needs of complex modalities.

Pharmacokinetics, safety, and immunogenicity of HLX03, an adalimumab biosimilar, compared with reference biologic in healthy Chinese male volunteers: Results of a randomized, double-blind, parallel-controlled, phase 1 study

The primary objective of this randomized, double‐blind, parallel‐controlled study (from December 2016 to October 2018) was to evaluate pharmacokinetic (PK) equivalence of adalimumab biosimilar HLX03 and reference adalimumab in healthy volunteers, and to assess safety, and immunogenicity of HLX03. The primary PK endpoints were maximum observed plasma concentration (C_max) and area under the concentration curve from time zero to the last quantifiable concentration (AUC_0–t). Equivalence was determined if the 90% confidence interval (CI) of geometric least square mean ratio between the two treatment groups were within the predefined range of 80%–125%. Safety and immunogenicity were monitored during the study. Healthy Chinese males (N = 220) were randomized 1:1 to receive a single subcutaneous 40 mg dose of HLX03 or China (CN)‐sourced adalimumab. The ratios of the geometric mean of C_max and AUC_0–t were 102.2% and 105.7%, respectively, with corresponding 90% CIs falling in the predefined margins, which demonstrated PK equivalence between HLX03 and CN‐adalimumab. The incidence of treatment‐emergent adverse events (TEAEs) was similar in the two groups (73.8% and 66.0% in the HLX03 and CN‐adalimumab groups, respectively). Grade 3–4 TEAEs were reported in 7.5% and 5.7% of participants, respectively. The incidences of participants with antidrug antibodies (HLX03: 96.2%; CN‐adalimumab: 93.4%) or neutralizing antibodies (HLX03: 40.6%, CN‐adalimumab: 41.4%) were comparable between groups. This study demonstrated PK bioequivalence between HLX03 and CN‐adalimumab, with similar safety and immunogenicity profiles. These data support further clinical development of HLX03 as an adalimumab biosimilar.

Immunogenicity of Biologic and Biosimilar Therapies for Psoriasis and Impact of Novel Immunoassays for Immunogenicity Detection

Anti-drug antibodies (ADAs) may develop against originator biologic and biosimilar therapies used for the treatment of psoriasis and may be the cause of initial therapeutic non-response or diminished therapeutic response over time. Comparing immunogenicity between therapeutic agents is challenging owing to the variation in assays used for detection, among other reasons. Using the results of a PubMed search for psoriasis clinical trials disclosing the rates of ADAs for originator biologic and biosimilar therapies approved for the treatment of psoriasis within the last 5 years, this review discusses the rates and potential clinical impact of ADA formation in patients with psoriasis managed with originator biologic and biosimilar therapies, along with novel methods of ADA testing. Anti-drug antibodies are detectable in all biologic and biosimilar therapies approved for the treatment of psoriasis in the last 5 years, and the effect of ADAs on clinical response varies by agent. Novel immunoassays used for the detection of ADAs may have increased sensitivity compared with traditional assays, although the increased rate of detection may not correlate with decreased clinical response and the decision to test for the presence of ADAs may vary from patient to patient. Though ADA formation seems ubiquitous with the use of biologic agents for the treatment of psoriasis, the increased rates of ADAs detected by novel immunoassays may not necessarily correlate with decreased treatment efficacy.

Immunogenicity of biologic agents in rheumatology

Biologic agents have become a core component of therapeutic strategies for many inflammatory rheumatic diseases. However, perhaps reflecting the specificity and generally high affinity of biologic agents, these therapeutics have been used by rheumatologists with less consideration of their pharmacokinetics than that of conventional synthetic DMARDs. Immunogenicity was recognized as a potential limitation to the use of biologic agents at an early stage in their development, although regulatory guidance was relatively limited and assays to measure immunogenicity were less sophisticated than today. The advent of biosimilars has sparked a renewed interest in immunogenicity that has resulted in the development of increasingly sensitive assays, an enhanced appreciation of the pharmacokinetic consequences of immunogenicity and the development of comprehensive and specific guidance from regulatory authorities. As a result, rheumatologists have a greatly improved understanding of the field in general, including the factors responsible for immunogenicity, its potential clinical consequences and the implications for everyday treatment. In some specialties, immunogenicity testing is becoming a part of routine clinical management, but definitive evidence of its cost-effectiveness in rheumatology is awaited.

Understanding and Minimising Injection-Site Pain Following Subcutaneous Administration of Biologics: A Narrative Review

Injection-site pain (ISP) is a subjective side effect that is commonly reported with the subcutaneous administration of biological agents, yet it may only be a concern to some. Multiple factors related to the product formulation, such as pH, volume and excipients, and/or to the injection process have the potential to contribute to ISP, while patient-related factors, such as low body weight, gender and age, can make an individual more susceptible to experiencing ISP. While total elimination of ISP remains unlikely with any subcutaneously administered agent, it can be minimised by helping the patient to develop a confident and competent injection technique via robust and effective training. Careful management of patient expectations along with open discussion regarding the potential risk of ISP may serve to minimise treatment-related anxieties and, importantly, allow the patient to remain in control of his/her treatment. Other interventions to help minimise ISP include psychological interventions, allowing biologics to reach room temperature prior to injection, using the most suitable injection device for the individual patient and selecting an alternative drug formulation, when available. Productive patient–physician communication remains important in order to support and optimise treatment experience and adherence, while also providing the opportunity for patients to discuss any ISP-related issues.

Adalimumab Immunogenicity Is Negatively Correlated with Anti-Hinge Antibody Levels in Patients with Rheumatoid Arthritis

Patients with rheumatoid arthritis (RA) are frequently treated with anti-tumor necrosis factor-α immunoglobulin therapy but develop neutralizing antibodies against these drugs, necessitating therapeutic monitoring of drug concentrations and anti-drug antibodies. Patients with RA have multiple factors related to their autoimmune disposition that interfere with conventionally used methods to detect anti-drug antibodies. Currently deployed analytical methods have significant limitations that hinder clinical interpretation and/or routine use, and no method can detect immunogenicity and drug levels simultaneously to provide clinically meaningful recommendations. Given these limitations, the objective of this study was to identify sources of and associations with assay interference in patients with RA. We designed a modular immunogenicity and drug concentration detection technology to identify the factors that interfere with the detection of adalimumab and anti-adalimumab antibodies in a cohort of 206 patients with RA. Patients were included from the University of Pittsburgh Rheumatoid Arthritis Comparative Effectiveness Research registry. In this cohort, we analyzed clinical and plasma factors associated with anti-adalimumab and anti-hinge antibodies. A novel flow cytometry-based assay was developed and validated that simultaneously measures adalimumab and anti-adalimumab antibody concentrations, overcoming many of the interference factors that are limitations of conventional assays, including anti-fragment crystallizable (Fc) and anti-hinge antibodies. C-reactive protein (P = 0.035), Disease Activity Score-28 (DAS28) score (P = 0.002), and disease activity category (P = 0.009) were significantly associated with anti-adalimumab antibodies but not with anti-hinge antibodies (P > 0.05). Anti-hinge antibodies were inversely associated with drug-neutralizing antibodies (P = 0.002). In patients with RA, anti-hinge antibodies may have a potential protective effect against the development of anti-adalimumab antibodies. SIGNIFICANCE STATEMENT: Using a novel cytometric assay that simultaneously measures drug and anti-drug antibodies, we overcame many interferences that hinder the clinical interpretation of adalimumab immunogenicity testing. Our investigation in patients with RA demonstrated that immunogenicity impaired the pharmacological action of adalimumab via analysis of RA disease severity markers. We also demonstrate that patients with anti-hinge antibodies had lower anti-adalimumab antibody levels and decreased drug neutralization. Our results suggest that anti-hinge antibodies can predict adalimumab immunogenicity before the start of therapy.

Comparison of Rituximab Originator With CT-P10 Biosimilar in Patients With Primary Sjögren's Syndrome: A Retrospective Analysis in a Real-Life Setting

Introduction: Over the last two decades, rituximab (RTX) has been widely used, albeit off-label, in primary Sjögren's syndrome (pSS). Several studies reported that B lymphocyte depletion with RTX is effective to treat some aspects within the disease spectrum, by reducing disease activity and affecting the inflammation and lymphoid organization that occur in target tissues. Notwithstanding, randomized controlled trials failed to confirm such evidence. With the recent release of several RTX biosimilars on the market, their efficacy and safety compared to the originator must be ascertained across different indications. This study aimed at comparing efficacy and safety of RTX originator and CT-P10 RTX biosimilar in pSS patients in a real-life setting.

Methods: Clinical and laboratory records of pSS patients referring to a tertiary rheumatology clinic were retrospectively evaluated. Patients having received at least two courses of either RTX originator or CT-P10 with complete data at baseline and after 12, 24, 36, and 48 weeks of treatment were enrolled. Disease activity was assessed with the EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI) and its clinical version without the biological domain (clinESSDAI). Patient-reported symptoms were assessed with the EULAR Sjögren's Syndrome Patient-Reported Index (ESSPRI). Adverse events (AEs) occurring during the study period were also recorded.

Results: Nine patients who received RTX originator and eight patients who received CT-P10 were enrolled. Baseline clinical and serological features, including ESSDAI and ESSPRI, were similar in the two treatment groups. An efficient depletion of circulating CD19⁺ B lymphocytes was achieved in both treatment arms. Both RTX originator and CT-P10 significantly reduced ESSDAI and clinESSDAI by week 24, and no difference between the groups was observed at any timepoint. Conversely, changes of ESSPRI overtime did not differ between the two treatment arms and were not statistically significant compared to corresponding baseline values. With regard to safety, at 48 weeks of follow-up, only four mild AEs (two in the RTX originator and two in the CT-P10 group) were observed.

Conclusion: Our study provides the first evidence that, at 48 weeks of follow-up, RTX originator and CT-P10 display similar efficacy and safety profiles in pSS.

Evolution of infliximab biosimilar in inflammatory bowel disease: from intravenous to subcutaneous CT-P13

INTRODUCTION

Biologic drugs have significantly improved the treatment of ulcerative colitis (UC) and Crohn's disease (CD). However, the availability of these drugs is limited by their high cost. Infliximab was the first biologic to be approved for inflammatory bowel diseases (IBD). After its patent expired other manufactures developed biosimilar versions, among which CT-P13, and licensed them thorough an expedite process.

AREAS COVERED

The aim of this review is to summarize the available evidence on CT-P13 use in IBD, with particular interest in the phase II trials of a subcutaneous version of CT-P13.

EXPERT OPINION

Biosimilars, such as CT-P13, are an important resource for health-care systems. Although CT-P13 approval in IBD was based on extrapolation, subsequent studies confirmed its clinical equivalence to originator infliximab. A new subcutaneous formulation of CT-P13 showed promising results in phase I and II trials in both CD and UC. Clinical efficacy and safety were comparable and interestingly serum drug doses appeared to be more stable than conventional intravenous CT-P13. If these preliminary results will be confirmed, the first sub-cutaneous version of infliximab could soon be available for IBD.

Immunogenicity of TNF-Inhibitors

Tumor necrosis factor inhibitors (TNFi) have significantly improved treatment outcome of rheumatic diseases since their incorporation into treatment protocols two decades ago. Nevertheless, a substantial fraction of patients experiences either primary or secondary failure to TNFi due to ineffectiveness of the drug or adverse reactions. Secondary failure and adverse events can be related to the development of anti-drug antibodies (ADA). The earliest studies that reported ADA toward TNFi mainly used drug-sensitive assays. Retrospectively, we recognize this has led to an underestimation of the amount of ADA produced due to drug interference. Drug-tolerant ADA assays also detect ADA in the presence of drug, which has contributed to the currently reported higher incidence of ADA development. Comprehension and awareness of the assay format used for ADA detection is thus essential to interpret ADA measurements correctly. In addition, a concurrent drug level measurement is informative as it may provide insight in the extent of underestimation of ADA levels and improves understanding the clinical consequences of ADA formation. The clinical effects are dependent on the ratio between the amount of drug that is neutralized by ADA and the amount of unbound drug. Pharmacokinetic modeling might be useful in this context. The ADA response generally gives rise to high affinity IgG antibodies, but this response will differ between patients. Some patients will not reach the phase of affinity maturation while others generate an enduring high titer high affinity IgG response. This response can be transient in some patients, indicating a mechanism of tolerance induction or B-cell anergy. In this review several different aspects of the ADA response toward TNFi will be discussed. It will highlight the ADA assays, characteristics and regulation of the ADA response, impact of immunogenicity on the pharmacokinetics of TNFi, clinical implications of ADA formation, and possible mitigation strategies.