Pharmacodynamics of interferon beta in multiple sclerosis patients with or without serum neutralizing antibodies

A randomized pharmacokinetic-pharmacodynamic evaluation of the potential biosimilar interferon beta-1a product, CinnoVex®

Background: The objective of the trial was to evaluate the bioequivalence of the interferon beta-1a (IFN beta-1a) biosimilar product candidate CinnoVex® with the reference product Avonex® by comparing the pharmacokinetics/pharmacodynamics (PK/PD), safety and immunogenicity of the two products in healthy subjects.Methods: A total of 41 healthy subjects were randomized in a two-stage design to receive single doses of CinnoVex® and Avonex®. The primary PK endpoint was the area under the concentration-time curve from time 0 to the last quantifiable concentration (AUC_0-last). Additional PK parameters, safety and immunogenicity were evaluated as secondary endpoints. The main secondary PD endpoints were the areas under the concentration-time curves from time 0 to 168 hours (AUC_0-168h) of the PD biomarkers.Results: The two products demonstrated similar PK parameters, and the 90% confidence interval (CI) of the primary PK endpoint was within the bioequivalence acceptance limit. No serious adverse events were reported, and all adverse events (AE) were mild or moderate in severity. Anti-drug antibodies were not observed in any of the study participants.Conclusion: This study demonstrated PK/PD bioequivalence between CinnoVex® and Avonex®. The safety and tolerability profiles of both products were similar.Clinical trials registration: EudraCT Number 2016-000139-41.

Pharmacokinetic considerations in the treatment of multiple sclerosis with interferon-β

INTRODUCTION

Interferon-β (IFNβ) is well established as a disease-modifying treatment for patients with multiple sclerosis. Several preparations of the biopharmaceutical are available differing in protein structure, formulation, dose as well as frequency and route of administration. Recently, a pegylated form of IFNβ has been marketed.

AREAS COVERED

Following a PubMed database search, we provide an overview of what is presently known about the pharmacokinetics (PK) of IFNβ including its absorption, distribution, metabolism and elimination. Also, we discuss the association with clinically relevant issues such as treatment efficacy, adverse events and anti-drug antibodies.

EXPERT OPINION

IFNβ has a bioavailability of ∼ 30% after subcutaneous or intramuscular administration, shows peak serum concentrations within several hours, has a half-life of < 1 day and is eliminated by a renal and hepatic pathway. PK parameters do not substantially differ between the types of IFNβ and routes of administration; only pegylation of IFNβ results in substantially increased and prolonged PK. Although no clinical dose-effect relationship could be established, there is an association of IFNβ dose with magnetic resonance imaging outcome parameters. Furthermore, there is an association of IFNβ serum levels with the occurrence of adverse events and anti-drug antibodies.

The effect of intravenous interferon-beta-1a (FP-1201) on lung CD73 expression and on acute respiratory distress syndrome mortality: an open-label study

BACKGROUND

Pulmonary vascular leakage occurs early in acute respiratory distress syndrome (ARDS). Mortality is high (35-45%), but no effective pharmacotherapy exists. Production of anti-inflammatory adenosine by ecto-5'-nucleotidase (CD73) helps maintain endothelial barrier function. We tested whether interferon-beta-1a (IFN-beta-1a), which increases CD73 synthesis, can reduce vascular leakage and mortality in patients with ARDS.

METHODS

In ex-vivo studies, we first established that IFN-beta-1a induced CD73 up-regulation in cultured human lung tissue samples. We then tested the safety, tolerability, and efficacy of intravenous human recombinant IFN-beta-1a (FP-1201) in patients with ARDS in an open-label study (comprising dose-escalation and expansion phases). We recruited patients from eight intensive care units in the UK. Eligible patients were aged 18 years or older, had ARDS, and were being treated with assisted ventilation. We established an optimal tolerated dose (OTD) in the first, dose-escalation phase. Once established, we gave all subsequently enrolled patients the OTD of intravenous FP-1201 for 6 days. We assessed 28-day mortality (our primary endpoint) in all patients receiving the OTD versus 28-day mortality in a group of patients who did not receive treatment (this control group comprised patients in the study but who did not receive treatment because they were screened during the safety windows after dose escalation). This trial is registered with ClinicalTrials.gov, number NCT00789685, and the EU Clinical Trials Register EudraCT, number 2008-000140-13.

FINDINGS

IFN-beta-1a increased the number of CD73-positive vessels in lung culture by four times on day 1 (p=0·04) and by 14·3 times by day 4 (p=0·004). For the clinical trial, between Feb 23, 2009, and April 7, 2011, we identified 150 patients, of whom 37 were enrolled into the trial and given treatment. The control group consisted of 59 patients who were recruited to take part in the study, but who did not receive treatment. Demographic characteristics and severity of illness did not differ between treatment and control groups. The optimal tolerated FP-1201 dose was 10 μg per day for 6 days. By day 28, 3 (8%) of 37 patients in the treatment cohort and 19 (32%) of 59 patients in the control cohort had died-thus, treatment with FP-1201 was associated with an 81% reduction in odds of 28-day mortality (odds ratio 0·19 [95% CI 0·03-0·72]; p=0·01).

INTERPRETATION

FP-1201 up-regulates human lung CD73 expression, and is associated with a reduction in 28-day mortality in patients with ARDS. Our findings need to be substantiated in large, prospective randomised trials, but suggest that FP-1201 could be the first effective, mechanistically targeted, disease-specific pharmacotherapy for patients with ARDS.

Use of a standardized MxA protein measurement-based assay for validation of assays for the assessment of neutralizing antibodies against interferon-β

Effective monitoring of the development of neutralizing antibodies (NAbs) against IFN-β in multiple sclerosis (MS) patients on IFN-β therapy is important for clinical decision making and disease management. To date, antiviral assays have been the favored approach for NAb determination, but variations in assay conditions between laboratories and the increasing use of novel assays have contributed to the reporting of inconsistent antibody data between laboratories and between products. This study, undertaken at the request of the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA), is a joint effort by manufacturers of IFN-β products (approved in Europe) towards harmonization of a NAb assay that facilitates generation of comparable NAb data, which, in conjunction with clinical outcomes, should prove useful for clinicians treating MS patients with IFN-β products. This article describes the standardized cellular myxovirus resistance protein A (MxA) protein measurement-based assay for detection of IFN-β NAbs and its use for the validation of assays used for the quantitative determination of such antibodies. Although titers varied between laboratories and the products used, utilization of IFN-β1a rather than IFN-β1b as the challenge antigen produced more consistent results in the NAb assay. Adoption of the standardized assay improves comparability between laboratories circumventing problems that arise when different, nonstandardized assays are employed for immunogenicity assessment. Based on the data, the EMA recommended for standardization purposes, the use of IFN-β1a in NAb assays, independent of the therapeutic product used for therapy and validation of new NAb procedures against the standardized assay described.

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

All biotherapeutics have the potential to generate anti-drug antibodies (ADAs) in patients. The main factors leading to an immune response are thought to be product, treatment and patient related. In this review, reasons for the formation of ADAs, and particularly neutralizing antibodies (NAbs), are considered, with a focus on IFN-β as a well-studied example. The time course for the production of NAbs, the measurement of NAbs, the defining of IFN-β responders and non-responders, the implications for disease progression in patients, and future methods for avoiding the production of ADAs and of tolerizing patients are considered.

Neutralizing antibodies against interferon-Beta

The development of neutralizing antibodies (NAbs) is a major problem in multiple sclerosis (MS) patients treated with interferon-beta (IFN-ß). Whereas binding antibodies (BAbs) can be demonstrated in the vast majority of patients, only a smaller proportion of patients develop NAbs. The principle in NAb in vitro assays is the utilization of cultured cell lines that are responsive to IFN-ß. The cytopathic effect (CPE) assay measures the capacity of NAbs to neutralize IFN- ß's protective effect on cells challenged with virus and the MxA induction assay measures the ability of NAbs to reduce the IFN-ß-induced expression of MxA, either at the mRNA or the protein level. A titer of >20 neutralizing units/ml traditionally defines NAb posi-tivity. NAbs in high titers completely abrogate the in vivo response to IFN-ß, whereas the effect of low and intermediate titers is unpredictable. As clinically important NAbs appear only after 9-18 months IFN- ß0 therapy, short-term studies of two years or less are unsuitable for evaluation of clinical NAb effects. All long-term trials of three years or more concordantly show evidence of a detrimental effect of NAbs on relapses, disease activity on MRI, or on disease progression. Persistent high titers of NAbs indicate an abrogation of the biological response and, hence, absence of therapeutic efficacy, and this observation should lead to a change of therapy. As low and medium titers are ambiguous treatment decisions in patients with low NAb titres should be guided by determination of in vivo mRNA MxA induction and clinical disease activity.

Human MxA protein: an interferon-induced dynamin-like GTPase with broad antiviral activity

The human myxovirus resistance protein 1 (MxA) is a key mediator of the interferon-induced antiviral response against a wide range of viruses. MxA expression is tightly regulated by type I and type III interferons, requires signal transducer and activator of transcription 1 signaling, and is not inducible directly by viruses or other stimuli. MxA shares many properties with the dynamin superfamily of large GTPases. It consists of 3 domains, namely, an N-terminal GTPase domain that binds and hydrolyses GTP, a middle domain mediating self-assembly, and a carboxy-terminal GTPase effector domain. Like dynamin, MxA has the ability to self-assemble into highly ordered oligomers and to form ring-like structures around liposomes, inducing liposome tubulation. The structural details of MxA oligomerization have recently been elucidated, providing new insights into the antiviral mechanism of this mechanochemical enzyme. The structural and functional data suggest that MxA targets the nucleoprotein of MxA-sensitive viruses. Thus, MxA may form oligomeric rings around tubular nucleocapsid structures, thereby inhibiting their transcriptional and replicative function. Here we briefly review the most salient features of MxA expression and antiviral function.

An assessment of biological potency and molecular characteristics of different innovator and noninnovator interferon-beta products

Approved innovator products and their noninnovator "copy" versions are likely to vary in their quality, eg, physicochemical characteristics and biological activity, with important implications for clinical efficacy and safety. Therefore, it is important to study and thoroughly evaluate the noninnovator products in comparison with approved products at the preclinical and clinical stages. We have obtained 4 noninnovator interferon (IFN)-β-1a products currently marketed in Latin America and Iran and compared these with approved IFN-β-1a products (Avonex and Rebif) obtained from the same geographical regions with respect to biological potency, estimated by in vitro bioassays, and molecular characteristics, assessed by immunoblotting and high-performance liquid chromatography. In this article, we present our data showing that the noninnovator IFN-β-1a products can vary considerably in their biological potency. In addition, we showed that all IFN-β-1a products formulated with human serum albumin contained variable amounts of higher-molecular-weight aggregates of IFN-β-1a and adducts with human serum albumin, these being more prevalent in 2 noninnovator IFN-β-1a products where biological potency was reduced compared with approved IFN-β-1a products. Additionally, significant lot-to-lot variability was observed for one of the noninnovator products. Taken together, the results of this study highlight the need for not only thorough in vitro characterization, but also preclinical and clinical assessment to ensure patient safety and efficacy.

Recommendations for clinical use of data on neutralising antibodies to interferon-beta therapy in multiple sclerosis

The identification of factors that can affect the efficacy of immunomodulatory drugs in relapsing-remitting multiple sclerosis (MS) is important. For the available interferon-beta products, neutralising antibodies (NAb) have been shown to affect treatment efficacy. In June, 2009, a panel of experts in MS and NAbs to interferon-beta therapy convened in Amsterdam, Netherlands, under the auspices of the Neutralizing Antibodies on Interferon beta in Multiple Sclerosis consortium, a European-based project of the 6th Framework Programme of the European Commission, to review and discuss data on NAbs and their practical consequences for the treatment of patients with MS on interferon beta. The panel believed that information about NAbs and other markers of biological activity of interferons (ie, myxovirus resistance protein A [MxA]) can be integrated with clinical and imaging indicators to guide individual treatment decisions. In cases of sustained high-titre NAb positivity and/or lack of MxA bioactivity, a switch to a non-interferon-beta therapy should be considered. In patients who are doing poorly clinically, therapy should be switched irrespective of NAb or MxA bioactivity.

Neutralizing antibodies explain the poor clinical response to interferon beta in a small proportion of patients with multiple sclerosis: a retrospective study

Background

Neutralizing antibodies (NAbs) against Interferon beta (IFNβ) are reported to be associated with poor clinical response to therapy in multiple sclerosis (MS) patients. We aimed to quantify the contribution of NAbs to the sub-optimal response of IFNβ treatment.

Methods

We studied the prevalence of NAbs in MS patients grouped according to their clinical response to IFNβ during the treatment period. Patients were classified as: group A, developing ≥ 1 relapse after the first 6 months of therapy; group B, exhibiting confirmed disability progression after the first 6 months of therapy, with or without superimposed relapses; group C, presenting a stable disease course during therapy. A cytopathic effect assay tested the presence of NAbs in a cohort of ambulatory MS patients treated with one of the available IFNβ formulations for at least one year. NAbs positivity was defined as NAbs titre ≥ 20 TRU.

Results

Seventeen patients (12.1%) were NAbs positive. NAbs positivity correlated with poorer clinical response (p < 0.04). As expected, the prevalence of NAbs was significantly lower in Group C (2.1%) than in Group A (17.0%) and Group B (17.0%). However, in the groups of patients with a poor clinical response (A, B), NAbs positivity was found only in a small proportion of patients.

Conclusion

The majority of patients with poor clinical response are NAbs negative suggesting that NAbs explains only partially the sub-optimal response to IFNβ.

Neutralizing antibodies to interferon-beta and other immunological treatments for multiple sclerosis: prevalence and impact on outcomes

Biopharmaceuticals can induce antibodies, which interact with and neutralize the therapeutic effect of such drugs and are therefore termed neutralizing antibodies (NAbs). In the treatment of multiple sclerosis, NAbs against interferon (IFN)-beta and natalizumab have been recognized. The prevalence of NAbs against different IFNbeta preparations varies widely, mainly depending on the product but also on other factors such as amino acid sequence variations, glycosylation, formulation, route and frequency of application, dose, duration of treatment and patient characteristics (human leukocyte antigen [HLA] status). IFNbeta-1a given intramuscularly induces significantly less NAbs than any other IFNbeta formulation. The longitudinal development of NAbs also differs between IFNbeta preparations, with higher reversion rates in IFNbeta-1b-treated compared with IFNbeta-1a-treated patients. The negative effect of NAbs on various outcome measures is very consistent across many studies, specifically when observation periods are longer than 2 years. NAbs against natalizumab occur less frequently (6%) and, like NAbs against IFNbeta, they are associated with a loss of clinical and radiological efficacy of the drug.

Current approaches to the identification and management of breakthrough disease in patients with multiple sclerosis

Disease-modifying drugs (DMDs) for relapsing-remitting multiple sclerosis (RRMS) are only partly effective -- breakthrough disease commonly occurs despite treatment. Breakthrough disease is predictive of continued disease activity and a poor prognosis. Availability of several DMDs offers the possibility of tailoring treatment to individual patients with RRMS and altering treatment in patients with breakthrough disease. However, no biological or imaging markers have been validated to guide initial treatment, markers of individual responsiveness to DMDs are scarce, and there is no class 1 evidence to guide alternative therapy in patients with breakthrough disease. In this Review, we discuss proposed strategies to monitor patients with RRMS being treated with DMDs, outline approaches to identifying therapeutic response in individual patients, review MRI and biological markers of treatment response, and summarise the role of antibodies in biological therapies. We also outline possible strategies for the management of patients with breakthrough disease and highlight areas in which research is needed.

Biological response genes after single dose administration of interferon beta-1b to healthy male volunteers

Treatment with interferon beta-1b (IFNB-1b) is clinically effective in multiple sclerosis patients. However, the mechanism of action is only partially understood, and validated biological response markers are lacking. We assessed IFNB-1b-induced transcriptional changes by microarray technology. Healthy male volunteers received 250 mug IFNB-1b or placebo in a double-blind, randomized controlled trial (n=5 per group). Most transcripts demonstrated peak levels after 6-12 h and returned to baseline after 48 h. We identified 227 differentially regulated genes including novel and previously described markers. This panel may become a valuable tool for development of new IFNB-1b formulations and assessment of clinical drug effects.

Reflections on the immunogenicity of therapeutic proteins

Therapeutic proteins are now established as a major class of medication with proven efficacy in treating a wide range of diseases. The administration of such proteins to patients can lead to the development of antibodies that are able to bind and eventually neutralise the protein administered. Many advances have been made in understanding the immunogenicity of therapeutic proteins, but opinions are often conflicting. Although it is important to understand more about the antibodies generated against therapeutic proteins, the need for future research must not be neglected, so that other relevant factors can be identified and addressed to maximise treatment benefits for patients.