Development of resistance to biologic therapies with reference to IFN-β

Anti-cytokine autoantibodies: mechanistic insights and disease associations

Anti-cytokine autoantibodies (ACAAs) are increasingly recognized as modulating disease severity in infection, inflammation and autoimmunity. By reducing or augmenting cytokine signalling pathways or by altering the half-life of cytokines in the circulation, ACAAs can be either pathogenic or disease ameliorating. The origins of ACAAs remain unclear. Here, we focus on the most common ACAAs in the context of disease groups with similar characteristics. We review the emerging genetic and environmental factors that are thought to drive their production. We also describe how the profiling of ACAAs should be considered for the early diagnosis, active monitoring, treatment or sub-phenotyping of diseases. Finally, we discuss how understanding the biology of naturally occurring ACAAs can guide therapeutic strategies.

Glycosylation shapes the efficacy and safety of diverse protein, gene and cell therapies

Over recent decades, therapeutic proteins have had widespread success in treating a myriad of diseases. Glycosylation, a near universal feature of this class of drugs, is a critical quality attribute that significantly influences the physical properties, safety profile and biological activity of therapeutic proteins. Optimizing protein glycosylation, therefore, offers an important avenue to developing more efficacious therapies. In this review, we discuss specific examples of how variations in glycan structure and glycoengineering impacts the stability, safety, and clinical efficacy of protein-based drugs that are already in the market as well as those that are still in preclinical development. We also highlight the impact of glycosylation on next generation biologics such as T cell-based cancer therapy and gene therapy.

Biosimilar Drugs for Multiple Sclerosis: An Unmet International Need or a Regulatory Risk?

Multiple sclerosis (MS) more than any other neurological disorder has experienced a tremendous progress in available evidence-based innovator disease modifying therapies (DMT). These medications include injectable complex nonbiological drugs (CNBD), the injectable biological products β-interferons-1a and -1b, and the infusible monoclonal antibodies (MAB), as well as oral synthetic therapeutic molecules. The degree of efficacy and adverse effects profile is variable. By the end of 2019, all medications have been approved for relapsing forms of MS, including five with indication for clinically isolated syndrome (CIS), two for active secondary progressive MS, and one for primary progressive MS. With the advent of the first generation or "platform" injectable DMT in the 1990s the cost of MS care increased substantially driven basically by the cost of these therapies. As new drugs licensed by health agencies appeared in the global market, the cost of these agents notably increased augmenting the economic gravamen of disease particularly in North America This industrial phenomenon has been promoted by the remarkable profits obtained by the biopharmaceutical companies producing these medications, costs increasing about seven times per patient per year in the span of two decades. The global MS drug market was valued at US$16.3 billion in 2016, expecting to reach US$27.8 billion by 2025. The societal and economic effect of these costs constitute an international concern for health systems which adjudicate an increasing portion of financial resources to MS care. This effect has had a more notorious impact in emerging countries with economies in development. In the early 2000s the industry producers of biosimilar molecules initiated the concept of manufacturing follow-on biosimilar therapeutic options for MS available at a reduced cost without affecting efficacy and safety. Latin American biotechnological companies from Mexico, Argentina and Uruguay, introduced into the regional markets biosimilar β-interferons. These products were licensed by the local regulatory agencies without challenging pharmacological profile and their claims of similarity with the innovator medications. In the licensing process, biosimilar manufactures have typically utilized published literature and phase III clinical trials data previously acquired by the brand medication ("third approval pathway''). This has raised concerns among local neurological communities and patient organizations in the area. This situation is compounded by the fact that no discernible health cost savings have resulted since their introduction in Latin American countries. In some European countries where the health care system, public and private systems, regulated by Ministries of Health, negotiate with the pharmaceutical industry drug pricing and payment systems. The business scenario has stimulated local industries to produce follow-on biosimilar medications, theoretically to compete or replace the original brands. Countries such as Iran who have experienced a substantial increase in MS prevalence (101.19 per 100,000 inhabitants) has enabled their national Food and Drug Organization (FDO) to license locally produced biosimilar interferon 1-a and 1-b based on somewhat limited clinical studies. The Ministry of Health of the Russian Federation, approved the first biosimilar β-interferon-1a (44 mcg subcutaneous administration) manufactured in the country and developed in accordance to the guidelines of the European Medicine Agency (EMA) for phase I and phase III studies. The EMA, however, along with other international licensing agencies: United States Food and Drug Agency (FDA), Health Canada, the Japanese Pharmaceuticals and Medical Devices Agency (PMDA), the UK Medicines and Healthcare Products Regulatory Agency (MHPRA), and others, have produced strict guidelines regulating registration of biosimilar medicines. Thus far these agencies have not approved any interferon or MAB for MS based on these principles. The main obstacles for the approval of biosimilar medications by international health agencies is their consistent inability to demonstrate therapeutic equivalence through physiochemistry, biology, immunogenicity aspects, molecular behavior and clinical studies, preferably through a controlled phase III study, or ideally, utilizing a comparative head-to-head trial with the innovator. Recommendations proposed by experts from the Latin American region to guarantee production quality of biosimilar products, efficacy and safety, include strict application of current regulations; avoid uncontrolled interchangeability; implement strong pharmacovigilance; educate healthcare professionals and regulatory officials on the different issues involved in the biosimilarity concept and use evidence-based decision for therapy selection. The main priority should always be the protection and well-being of the patient irrespectively of therapy availability or pharmacoeconomic issues.

Overview of Antibody Drug Delivery

Monoclonal antibodies (mAbs) are one of the most important classes of therapeutic proteins, which are used to treat a wide number of diseases (e.g., oncology, inflammation and autoimmune diseases). Monoclonal antibody technologies are continuing to evolve to develop medicines with increasingly improved safety profiles, with the identification of new drug targets being one key barrier for new antibody development. There are many opportunities for developing antibody formulations for better patient compliance, cost savings and lifecycle management, e.g., subcutaneous formulations. However, mAb-based medicines also have limitations that impact their clinical use; the most prominent challenges are their short pharmacokinetic properties and stability issues during manufacturing, transport and storage that can lead to aggregation and protein denaturation. The development of long acting protein formulations must maintain protein stability and be able to deliver a large enough dose over a prolonged period. Many strategies are being pursued to improve the formulation and dosage forms of antibodies to improve efficacy and to increase the range of applications for the clinical use of mAbs.

The blood-brain barrier

In autoimmune neurologic disorders, the blood-brain barrier (BBB) plays a central role in immunopathogenesis, since this vascular interface is an entry path for cells and effector molecules of the peripheral immune system to reach the target organ, the central nervous system (CNS). The BBB's unique anatomic structure and the tightly regulated interplay of its cellular and acellular components allow for maintenance of brain homeostasis, regulation of influx and efflux, and protection from harm; these ensure an optimal environment for the neuronal network to function properly. In both health and disease, the BBB acts as mediator between the periphery and the CNS. For example, immune cell trafficking through the cerebral vasculature is essential to clear microbes or cell debris from neural tissues, while poorly regulated cellular transmigration can underlie or worsen CNS pathology. In this chapter, we focus on the specialized multicellular structure and function of the BBB/neurovascular unit and discuss how BBB breakdown can precede or be a consequence of neuroinflammation. We introduce the blood-cerebrospinal fluid barrier and include a brief aside about evolutionary aspects of barrier formation and refinements. Lastly, since restoration of barrier function is considered key to ameliorate neurologic disease, we speculate about new therapeutic avenues to repair a damaged BBB.

Therapeutic Plasma Exchange in Multiple Sclerosis Patients with Abolished Interferon-beta Bioavailability

BACKGROUND

Neutralizing antibodies (NAb) to interferon-beta (IFN-β) are associated with reduced bioactivity and efficacy of IFN-β in multiple sclerosis (MS). The myxovirus resistance protein A (MxA) gene expression is one of the most appropriate markers of biological activity of exogenous IFN-β. We hypothesized that therapeutic plasma exchange (TPE) can restore the ability of IFN-β to induce the MxA mRNA expression and that maintenance plasmapheresis can sustain the bioavailability of IFN-β.

MATERIAL AND METHODS

Eligible patients underwent 4 primary separate plasma exchange sessions. After the induction TPE sessions, they were transferred to maintenance plasmapheresis. Bioactivity of IFN-β was expressed as in vivo MxA mRNA induction in whole blood using RT-qPCR.

RESULTS

Six patients with low IFN-β bioavailability detected by the MxA mRNA response were included. Four patients became biological responders after induction plasmapheresis. In 2 patients an increase of MxA mRNA expression was found, but the values persisted below the cut-off and the patients remained as "poor biological responders". The effect of maintenance plasmapheresis was transient: MxA mRNA expression values reverted to the baseline levels after 1-2 months.

CONCLUSIONS

Therapeutic plasma exchange is able to restore the bioavailability of IFN-β in the majority of studied patients, but the effect of TPE on the IFN-β bioavailability was transient.

Antibody dissociation rates are predictive of neutralizing antibody (NAb) course: a comparison of interferon beta-1b-treated Multiple Sclerosis (MS) patients with transient versus sustained NAbs

A proportion of multiple sclerosis (MS) patients treated with interferon-β (IFNβ) develop neutralizing antibodies (NAbs), which can reduce therapeutic efficacy. In the Betaseron/Betaferon in Newly Emerging MS for Initial Treatment (BENEFIT) study, 88/277 patients developed NAbs, 48 having transient positivity and 29 having sustained positivity. This study aimed to investigate the antibody binding characteristics of serial sera in a subset of these two patient groups. Using Biacore™, a surface plasmon resonance-based technology that monitors biomolecular interactions in real time, we immobilized pure IFNβ-1b and analyzed antibody binding responses and dissociation rates of these sera. NAb titers correlated directly with binding responses and inversely with dissociation rates, and sera from sustained NAb patients demonstrated significantly higher binding responses and slower dissociation rates than sera from transient NAb patients. Thus, transient and sustained NAbs are quantitatively and qualitatively different, and interestingly, binding responses and dissociation rates at month 12 could predict the NAb course.

Do neutralising antibodies against exogenous interferon-beta inhibit endogenous signalling pathways?

INTRODUCTION

Interferon-beta (IFNβ) is currently the most used disease-modifying treatment for relapsing-remitting multiple sclerosis (RRMS), but it can lead to the production of neutralising antibodies (NABs) against IFNβ.

CLINICAL CASE

A lady with a past history of genital herpes was diagnosed with RRMS, started IFNβ treatment with a good initial response. Three years later her treatment was interrupted to become pregnant. After delivery she restarted IFNβ; she had more reactivations of genital herpes and experienced intermittent sensory symptoms often coinciding with herpes reactivation. High NABs titres against IFNβ were found. Since the introduction of famciclovir as prophylactic antiviral therapy and a switch from IFNβ to glatiramer acetate, herpes reactivations ceased and she had no further MS relapses.

CONCLUSION

Exacerbations of genital herpes coinciding with MS relapses suggest a potential link between the development of NABs and inhibition of anti-viral action of endogenous IFNβ. This case highlights that NABs not only decreases exogenous IFNβ treatment efficacy, but may also interfere with anti-viral properties of endogenous IFNβ. Investigating patients who are treated with biological medication will allow us to better understand the biology and signalling pathways in humans.

Guidelines on the clinical use for the detection of neutralizing antibodies (NAbs) to IFN beta in multiple sclerosis therapy: report from the Italian Multiple Sclerosis Study group

Interferon beta (IFNβ) was the first specific disease-modifying treatment licensed for relapsing-remitting multiple sclerosis, and is still one of the most commonly prescribed treatments. A strong body of evidence supports the effectiveness of IFNβ preparations in reducing the annual relapse rate, magnetic resonance (MRI) disease activity and disease progression. However, the development of binding/neutralizing antibodies (BAbs/NAbs) during treatment negatively affects clinical and MRI outcomes. Therefore, guidelines for the clinical use for the detection of NAbs in MS may result in better treatment of these patients. In October 2012, a panel of Italian neurologists from 17 MS clinics convened in Milan to review and discuss data on NAbs and their clinical relevance in the treatment of MS. In this paper, we report the panel's recommendations for the use of IFNβ Nabs detection in the early identification of IFNβ non-responsiveness and the management of patients on IFNβ treatment in Italy, according to a model of therapeutically appropriate care.

Hope and fear for interferon: the receptor-centric outlook on the future of interferon therapy

After several decades of intense clinical research, the great promise of Type I interferons (IFN1) as the anticancer wonder drugs that could cure or, at the very least, curb the progression of various oncological diseases has regrettably failed to deliver. Severe side effects and low efficacy of IFN1-based pharmaceutics greatly limited use of these drugs and further reduced the enthusiasm of clinical oncologists for future optimization of IFN1-based therapeutic modalities. Incredibly, extensive clinical studies to assess the efficacy of IFN1 alone or in combination with other anticancer drugs have not been paralleled by an equal scope in defining the determinants that confer cell sensitivity or refractoriness to IFN1. Given that all effects of IFN1 on malignant and benign cells alike are mediated by its receptor, the mechanisms regulating these receptor cell surface levels should play a paramount role in shaping the magnitude and duration of IFN1-elicited effects. These mechanisms and their role in controlling IFN1 responses, as well as an ability of a growing tumor to commandeer these events, are the focus of our review. We postulate that activation of numerous signaling pathways leading to elimination of IFN1 receptor occurs in cancer cells and benign cells that contribute to tumor tissue. We further hypothesize that activation of these eliminative pathways enables the escape from IFN1-driven suppression of tumorigenesis and elicits the primary refractoriness of tumor to the pharmaceutical IFN1.

Immunogenicity of therapeutic proteins: influence of aggregation

The elicitation of anti-drug antibodies (ADA) against biotherapeutics can have detrimental effects on drug safety, efficacy, and pharmacokinetics. The immunogenicity of biotherapeutics is, therefore, an important issue. There is evidence that protein aggregation can result in enhanced immunogenicity; however, the precise immunological and biochemical mechanisms responsible are poorly defined. In the context of biotherapeutic drug development and safety assessment, understanding the mechanisms underlying aggregate immunogenicity is of considerable interest. This review provides an overview of the phenomenon of protein aggregation, the production of unwanted aggregates during bioprocessing, and how the immune response to aggregated protein differs from that provoked by non-aggregated protein. Of particular interest is the nature of the interaction of aggregates with the immune system and how subsequent ADA responses are induced. Pathways considered here include 'classical' activation of the immune system involving antigen presenting cells and, alternatively, the breakdown of B-cell tolerance. Additionally, methods available to screen for aggregation and immunogenicity will be described. With an increased understanding of aggregation-enhanced immune responses, it may be possible to develop improved manufacturing and screening processes to avoid, or at least reduce, the problems associated with ADA.

Interferon-beta therapy in multiple sclerosis: the short-term and long-term effects on the patients' individual gene expression in peripheral blood

Therapy with interferon-beta (IFN-beta) is a mainstay in the management of relapsing-remitting multiple sclerosis (MS), with proven long-term effectiveness and safety. Much has been learned about the molecular mechanisms of action of IFN-beta in the past years. Previous studies described more than a hundred genes to be modulated in expression in blood cells in response to the therapy. However, for many of these genes, the precise temporal expression pattern and the therapeutic relevance are unclear. We used Affymetrix microarrays to investigate in more detail the gene expression changes in peripheral blood mononuclear cells from MS patients receiving subcutaneous IFN-beta-1a. The blood samples were obtained longitudinally at five different time points up to 2 years after the start of therapy, and the patients were clinically followed up for 5 years. We examined the functions of the genes that were upregulated or downregulated at the transcript level after short-term or long-term treatment. Moreover, we analyzed their mutual interactions and their regulation by transcription factors. Compared to pretreatment levels, 96 genes were identified as highly differentially expressed, many of them already after the first IFN-beta injection. The interactions between these genes form a large network with multiple feedback loops, indicating the complex crosstalk between innate and adaptive immune responses during therapy. We discuss the genes and biological processes that might be important to reduce disease activity by attenuating the proliferation of autoreactive immune cells and their migration into the central nervous system. In summary, we present novel insights that extend the current knowledge on the early and late pharmacodynamic effects of IFN-beta therapy and describe gene expression differences between the individual patients that reflect clinical heterogeneity.

Neutralizing antibodies are associated with a reduction of interferon-β efficacy during the treatment of Japanese multiple sclerosis patients

Multiple sclerosis (MS) is a chronic immune-mediated inflammatory demyelinating disease of the central nervous system. Interferon-β (IFN-β) has been used as the first line therapy for MS treatment in Japan, but patients treated with IFN-β may develop antibodies, known as neutralizing antibodies (NAbs), which abrogate its therapeutic effects. Intramuscular IFN-β 1a and subcutaneous IFN-β 1b are currently available in Japan, but large-scale studies evaluating the prevalence and clinical implications of NAbs against these IFN-β preparations in MS patients have only been performed in Caucasian populations. NAbs positivity has been reported to be associated with HLA-DRB1 alleles, suggesting that the positivity might differ among populations with distinct genetic backgrounds. Clinical information and sera were collected from 229 consecutive MS patients treated with IFN-β in 4 centers in Japan. Sera were tested for NAbs using a luciferase reporter gene assay. In total, 5.2% of IFN-β-1a-treated patients (4/77) and 30.3% of IFN-β-1b-treated patients (46/152) were positive for Nabs. The frequency of NAbs was highest in patients treated for 13 to 24 months. Clinical relapse and contrast-enhancing lesions in the magnetic resonance imaging increased together with NAbs titers in this group. In conclusion, the prevalence of NAbs in Japanese MS patients is similar to that in Caucasian populations and is associated with an increase in disease activity. Therefore, routine NAbs testing is recommended also in Asian populations to ensure the early identification of patients who would benefit from a change in therapy.

Clinical testing for neutralizing antibodies to interferon-β in multiple sclerosis

Biopharmaceuticals are drugs which are based on naturally occurring proteins (antibodies, receptors, cytokines, enzymes, toxins), nucleic acids (DNA, RNA) or attenuated microorganisms. Immunogenicity of these agents has been commonly described and refers to a specific antidrug antibody response. Such immunogenicity represents a major factor impairing the efficacy of biopharmaceuticals due to biopharmaceutical neutralization. Indeed, clinical experience has shown that induction of antidrug antibodies is associated with a loss of response to biopharmaceuticals and also with hypersensitivity reactions. The first disease-specific agent licensed to treat multiple sclerosis (MS) was interferon-β (IFNβ). In its various preparations, it remains the most commonly used first-line agent. The occurrence of antidrug antibodies has been extensively researched in MS, particularly in relation to IFNβ. However, much controversy remains regarding the significance of these antibodies and incorporation of testing into clinical practice. Between 2% and 45% of people treated with IFNβ will develop neutralizing antibodies, and this is dependent on the specific drug and dosing regimen. The aim of this review is to discuss the use of IFNβ in MS, the biological and clinical relevance of anti-IFNβ antibodies (binding and neutralizing antibodies), the incorporation of testing in clinical practice and ongoing research in the field.

Comparative binding of disulfide-bridged PEG-Fabs

Protein PEGylation is the most clinically validated method to improve the efficacy of protein-based medicines. Antibody fragments such as Fabs display rapid clearance from blood circulation and therefore are good candidates for PEGylation. We have developed PEG-bis-sulfone reagents 1 that can selectively alkylate both sulfurs derived from a native disulfide. Using PEG-bis-sulfone reagents 1, conjugation of PEG specifically targets the disulfide distal to the binding region of the Fab (Scheme 2 ). PEG-bis-sulfone reagents 1 (10-40 kDa) were used to generate the corresponding PEG-mono-sulfones 2 that underwent essentially quantitative conjugation to give the PEG-Fab product 4. Four Fabs were PEGylated: Fab(beva), Fab'(beva), Fab(rani), and Fab(trast). Proteolytic digestion of bevacizumab with papain gave Fab(beva), while digestion of bevacizumab with IdeS gave F(ab')(2-beva), which after reaction with DTT and PEG-mono-sulfone 2 gave PEG(2)-Fab'(beva). Ranibizumab, which is a clinically used Fab, was directly PEGylated to give PEG-Fab(rani). Trastuzumab was proteolytically digested with papain, and its corresponding Fab was PEGylated to give PEG-Fab(trast). Purification of the PEGylated Fabs was accomplished by a single ion exchange chromatography step to give pure PEG-Fab products as determined by silver-stained SDS-PAGE. No loss of PEG was detected post conjugation. A comparative binding study by SPR using Biacore with low ligand immobilization density was conducted using (i) VEGF(165) for the bevacizumab and ranibizumab derived products or (ii) HER2 for the trastuzumab derived products. VEGF(165) is a dimeric ligand with two binding sites for bevacizumab. HER2 has one domain for the binding of trastuzumab. Binding studies with PEG-Fab(beva) indicated that the apparent affinity was 2-fold less compared to the unPEGylated Fab(beva). Binding properties of the PEG-Fab(beva) products appeared to be independent of PEG molecular weight. Site-specific conjugation of two PEG molecules gave PEG(2×20)-Fab'(beva), whose apparent binding affinity was similar to that observed for PEG-Fab(beva) derivatives. The k(d) values were similar to those of the unPEGylated Fab(beva); hence, once bound, PEG-Fab(beva) remained bound to the same degree as Fab(beva). Biacore analysis indicated that both Fab(rani) and PEG(20)-Fab(rani) did not dissociate from the immobilized VEGF at 25 °C, but ELISA using immobilized VEGF showed 2-fold less apparent binding affinity for PEG(20)-Fab(rani) compared to the unPEGylated Fab(rani). Additionally, the apparent binding affinities for trastuzumab and Fab(trast) were comparable by both Biacore and ELISA. Biacore results suggested that trastuzumab had a slower association rate compared to Fab(trast); however, both molecules displayed the same apparent binding affinity. This could have been due to enhanced rebinding effects of trastuzumab, as it is a bivalent molecule. Analogous to PEG-Fab(beva) products, PEG(20)-Fab(trast) displayed 2-fold lower binding compared to Fab(trast) when evaluated by ELISA. The variations in the apparent affinity for the PEGylated Fab variants were all related to the differences in the association rates (k(a)) rather than the dissociation rates (k(d)). We have shown that (i) Fabs are well-matched for site-specific PEGylation with our bis-alkylation PEG reagents, (ii) PEGylated Fabs display only a 2-fold reduction in apparent affinity without any change in the dissociation rate, and (iii) the apparent binding rates and affinities remain constant as the PEG molecular weight is varied.