Safety, tolerability and pharmacokinetics of subcutaneous and intravenous anifrolumab in healthy volunteers

Tolerability, safety, and pharmacokinetics of GR1603 injection in healthy subjects: a randomized, double-blind, placebo-controlled single-dose escalation clinical trial

BACKGROUND

GR1603 is a monoclonal antibody targeting the type I interferon receptor. The aim of this study was to evaluate the safety, tolerability, pharmacokinetics, immunogenicity and pharmacodynamics of GR1603 in healthy volunteers.

METHODS

Healthy adults (≥18 years old) were enrolled in a placebo control, dose-escalation Phase I clinical trial receiving a single injectable dose of GR1603. Follow-up was 12 weeks. Adverse event (AE) profiles, vital signs, and blood samples were collected for assessment of safety, PK, and expression of type I interferon inducible genes.

RESULTS

Of the 46 subjects, 44 completed treatment. In the experimental group of 34 subjects (mean age 26.6 years), 30 experienced treatment-emergent adverse events (TEAEs), with a total of 102 occurrences, resulting in an incidence rate of 88.2%. The most commonly reported drug-related AEs were upper respiratory tract infection (17.6%), all of which were ≤ grade 2. GR1603 exhibits non-linear PK in the dose range of 0.1 mg/kg to 9 mg/kg. All samples were negative for anti-drug antibodies before and after dosing. The degrees of IFN gene signature were significantly inhibited in the higher dose groups.

CONCLUSION

The safety/tolerability, PK and exploratory metrics observed in this study support further clinical development of GR1603.

CLINICAL TRIAL REGISTRATION

www.chictr.org.cn/searchproj.html identifier is ChiCTR2100045628.

[Translated article] Use of Anifrolumab in Systemic Lupus Erythematosus, Cutaneous Lupus Erythematosus, and Other Autoimmune Dermatoses

Anifrolumab is an inhibitor of the type I interferon receptor subunit 1 (IFNAR1) recently approved for the management of moderate-to-severe systemic lupus erythematosus (SLE). In 2 clinical trials, it has proven effective to treat cutaneous signs. Although anifrolumab has not been indicated for cutaneous lupus erythematosus (CLE), multiple cases and case series (20 publications with a total of 78 patients) have shown good and rapid responses with this drug, both in subacute CLE and discoid lupus erythematosus, as well as in lupus panniculitis and perniosis. Two case reports of dermatomyositis have also experienced clinical improvement with anifrolumab. Clinical trials of this drug are ongoing for subacute CLE and discoid lupus erythematosus, systemic sclerosis, and progressive vitiligo. Its most common adverse effects are respiratory infections and herpes zoster. Anifrolumab may be a well-tolerated alternative in the management of CLE.

Physiology-based pharmacokinetic model with relative transcriptomics to evaluate tissue distribution and receptor occupancy of anifrolumab

Type I interferons contribute to the pathogenesis of several autoimmune disorders, including systemic lupus erythematosus (SLE), systemic sclerosis, cutaneous lupus erythematosus, and myositis. Anifrolumab is a monoclonal antibody that binds to subunit 1 of the type I interferon receptor (IFNAR1). Results of phase IIb and phase III trials led to the approval of intravenous anifrolumab 300 mg every 4 weeks (Q4W) alongside standard therapy in patients with moderate-to-severe SLE. Here, we built a population physiology-based pharmacokinetic (PBPK) model of anifrolumab by utilizing the physiochemical properties of anifrolumab, binding kinetics to the Fc gamma neonatal receptor, and target-mediated drug disposition properties. A novel relative transcriptomics approach was employed to determine IFNAR1 expression in tissues (blood, skin, gastrointestinal tract, lungs, and muscle) using mRNA abundances from bioinformatic databases. The IFNAR1 expression and PBPK model were validated by testing their ability to predict clinical pharmacokinetics over a large dose range from different clinical scenarios after subcutaneous and intravenous anifrolumab dosing. The validated PBPK model predicted high unbound local concentrations of anifrolumab in blood, skin, gastrointestinal tract, lungs, and muscle, which exceeded its IFNAR1 dissociation equilibrium constant values. The model also predicted high IFNAR1 occupancy with subcutaneous and intravenous anifrolumab dosing. The model predicted more sustained IFNAR1 occupancy ≥90% with subcutaneous anifrolumab 120 mg once-weekly dosing vs. intravenous 300 mg Q4W dosing. The results informed the dosing of phase III studies of anifrolumab in new indications and present a novel approach to PBPK modeling coupled with relative transcriptomics in simulating pharmacokinetics of therapeutic monoclonal antibodies.

Use of Anifrolumab in Systemic Lupus Erythematosus, Cutaneous Lupus Erythematosus, and Other Autoimmune Dermatoses

Anifrolumab is an inhibitor of the type I interferon receptor subunit 1 (IFNAR1) recently approved for the management of moderate-to-severe systemic lupus erythematosus (SLE). In 2 clinical trials, it has proven effective to treat cutaneous signs. Although anifrolumab has not been indicated for cutaneous lupus erythematosus (CLE), multiple cases and case series (20 publications with a total of 78 patients) have shown good and rapid responses with this drug, both in subacute CLE and discoid lupus erythematosus, as well as in lupus panniculitis and perniosis. Two case reports of dermatomyositis have also experienced clinical improvement with anifrolumab. Clinical trials of this drug are ongoing for subacute CLE and discoid lupus erythematosus, systemic sclerosis, and progressive vitiligo. Its most common adverse effects are respiratory infections and herpes zoster. Anifrolumab may be a well-tolerated alternative in the management of CLE.

Safety, Tolerability, Pharmacokinetics, and Immunogenicity of the Anti-IFNAR1 Monoclonal Antibody QX006N: A First-in-Human Single Ascending Dose Study in Healthy Chinese Volunteers

BACKGROUND AND OBJECTIVE

QX006N is a novel, humanized, IgG4κ monoclonal antibody targeting IFNAR1, developed for the treatment of systemic lupus erythematosus. This study aims to investigate the pharmacokinetics, safety, tolerability, and immunogenicity of QX006N when administered intravenously to healthy Chinese individuals.

METHODS

A double-blind, randomized, placebo-controlled, single-ascending-dose, phase I clinical trial was conducted comprising five cohorts (n = 10 per cohort, except n = 5 for the first cohort). Subjects in each cohort were randomly assigned in a 4:1 ratio to receive a single intravenous infusion of QX006N (0.3 mg/kg, 1.0 mg/kg, 3.0 mg/kg, 6.0 mg/kg, or 10.0 mg/kg) or placebo for 30 minutes. Tolerability assessments included adverse events, vital signs, 12-lead electrocardiogram, physical examination, and clinical laboratory tests. The serum concentration of QX006N was measured using the enzyme-linked immunosorbent assay method, and the anti-drug antibodies were detected using the electrochemiluminescence assay method.

RESULTS

QX006N demonstrated a favorable safety and tolerability profile throughout the study. All treatment-emergent adverse events were of Grade 1-2 (CTCAE Version 5.0), and no serious adverse events, deaths, or drug discontinuations because of treatment-emergent adverse events were observed. All drug-related treatment-emergent adverse events showed no clear dose-related trends. Following an intravenous infusion of QX006N at doses that ranged from 0.3 mg/kg to 10 mg/kg, the half-life increased from 24.7 to 208 hours in a dose-dependent manner, while clearance decreased from 0.0828 to 0.0065 L/h. The maximum concentration exhibited nearly dose-proportional increases, and the area under the curve displayed a more than dose-proportional increment with non-linear pharmacokinetic characteristics. The incidence of anti-drug antibodies was observed to increase over time for doses that ranged from 1.0 mg/kg to 10.0 mg/kg of QX006N, reaching its peak at day 57 (range 62.50-87.50%). Conversely, the incidence of anti-drug antibodies in the QX006N 0.3-mg/kg and placebo cohorts remained low.

CONCLUSIONS

QX006N demonstrated acceptable safety, tolerability, and pharmacokinetic characteristics in healthy subjects when administered as a single intravenous infusion at doses that ranged from 0.3 mg/kg to 10.0 mg/kg. Based on the pharmacokinetic and safety outcomes, a recommended effective dose of 300 mg is proposed for future phase Ib studies.

CLINICAL TRIAL REGISTRATION

This study has been registered at http://www.chinadrugtrials.org.cn/ under identifier CTR20212834.

Anifrolumab: first biologic approved in the EU not restricted to patients with a high degree of disease activity for the treatment of moderate to severe systemic lupus erythematosus

INTRODUCTION

Type 1 interferons (IFNs) play a crucial role in the pathogenesis of systemic lupus erythematosus (SLE) and various type I IFNs targeting therapeutic approaches have been developed. Anifrolumab, a monoclonal antibody that binds to the subunit 1 of the type I IFN receptor, has acquired considerable interest and has entered different clinical human trials willing to evaluate its efficacy and safety.

AREAS COVERED

This review summarizes the data obtained in phases 1, 2, and 3 clinical trials of anifrolumab for SLE patients. A focus is made on data of clinical efficacy and safety obtained in MUSE, TULIP-1 and TULIP-2 trials.

EXPERT OPINION/COMMENTARY

Anifrolumab is a promising therapeutic option for patients with SLE, currently authorized for moderate-to-severe SLE. Extensive real-world use is now going to generate data required to gain experience on the type of patients who benefit the most from the drug, and the exact positioning of anifrolumab in the therapeutic plan.

Clinical Pharmacokinetics, Pharmacodynamics, and Immunogenicity of Anifrolumab

The type I interferon (IFN) signaling pathway is implicated in the pathogenesis of systemic lupus erythematosus (SLE). Anifrolumab is a monoclonal antibody that targets the type I IFN receptor subunit 1. Anifrolumab is approved in several countries for patients with moderate to severe SLE receiving standard therapy. The approved dosing regimen of anifrolumab is a 300-mg dose administered intravenously every 4 weeks; this was initially based on the results of the Phase 2b MUSE and further confirmed in the Phase 3 TULIP-1 and TULIP-2 trials, in which anifrolumab 300-mg treatment was associated with clinically meaningful improvements in disease activity with an acceptable safety profile. There have been several published analyses of the pharmacokinetic and pharmacodynamic profile of anifrolumab, including a population-pharmacokinetic analysis of 5 clinical studies of healthy volunteers and patients with SLE, in which body weight and type I IFN gene expression were significant covariates identified for anifrolumab exposure and clearance. Additionally, the pooled Phase 3 SLE population has been used to evaluate how serum exposure may be related to clinical responses, safety risks, and pharmacodynamic effects of the 21-gene type I IFN gene signature (21-IFNGS). The relevance of 21-IFNGS with regard to clinical efficacy outcomes has also been analyzed. Herein, the clinical pharmacokinetics, pharmacodynamics, and immunogenicity of anifrolumab as well as results of population-pharmacokinetics and exposure-response analyses are reviewed.

An evaluation of anifrolumab for use in adults with systemic lupus erythematosus

INTRODUCTION

Type 1 interferons play a key role in the pathogenesis of systemic lupus erythematosus (SLE). An important clinical question is whether inhibiting the type 1 interferon pathway reduce the disease activity in SLE patients. This review evaluates the safety and efficacy of the monoclonal antibody against the type 1 interferon alpha receptor, anifrolumab, in patients with SLE.

AREAS COVERED

Key terms (SLE, type 1 interferon, anifrolumab) were used to query the PubMed database for phase 1, 2 and 3 clinical trials of anifrolumab for SLE patients. Phase 1 studies showed anifrolumab has non-linear pharmacokinetics and the optimal safe dose is 300 mg given intravenously every four weeks. The MUSE (phase 2) and the TULIP-2 (phase 3) trials showed that anifrolumab when added to standard therapy significantly reduced disease activity in SLE patients. Common adverse events associated with anifrolumab were upper respiratory and urinary infections as well as shingles.

EXPERT OPINION

Anifrolumab is an exciting new therapeutic for SLE patients. Additional analyses of the combined TULIP-1 and TULIP-2 datasets as well as future studies with anifrolumab will generate yet more data in SLE. No doubt anifrolumab will be studied in other diseases where type I interferons play an important role.

Nonlinear Population Pharmacokinetics of Anifrolumab in Healthy Volunteers and Patients With Systemic Lupus Erythematosus

We characterized the population pharmacokinetics of anifrolumab, a type I interferon receptor-blocking antibody. Pharmacokinetic data were analyzed from the anifrolumab (intravenous [IV], every 4 weeks) arms from 5 clinical trials in patients with systemic lupus erythematosus (SLE) (n = 664) and healthy volunteers (n = 6). Population pharmacokinetic modeling was performed using a 2-compartment model with parallel linear and nonlinear elimination pathways. The impact of covariates (demographics, interferon gene signature [IFNGS, high/low], disease characteristics, renal/hepatic function, SLE medications, and antidrug antibodies) on pharmacokinetics was evaluated. Time-varying clearance (CL) was characterized using an empirical sigmoidal time-dependent function. Anifrolumab exposure increased more than dose-proportionally from 100 to 1000 mg IV every 4 weeks. Based on population pharmacokinetics modeling, the baseline median linear CL was 0.193 L/day in IFNGS-high patients and 0.153 L/day in IFNGS-low/healthy volunteers. After a year, median anifrolumab linear CL decreased by 8.4% from baseline. Body weight and IFNGS were significant pharmacokinetic covariates, whereas age, sex, race, disease activity, SLE medications, and presence of antidrug antibodies had no significant effect on anifrolumab pharmacokinetics. Anifrolumab at a concentration of 300 mg IV every 4 weeks was predicted to be below the lower limit of quantitation in 95% of patients ≈10 weeks after a single dose and ≈16 weeks after stopping dosing at steady state. To conclude, anifrolumab exhibited nonlinear pharmacokinetics and time-varying linear CL; doses ≥300 mg IV every 4 weeks provided sustained anifrolumab concentrations. This study provides further evidence to support the use of anifrolumab 300 mg IV every 4 weeks in patients with moderate to severe SLE.

Type I Interferons in Systemic Lupus Erythematosus: A Journey from Bench to Bedside

Dysregulation of type I interferons (IFNs) has been implicated in the pathogenesis of systemic lupus erythematosus (SLE) since the late 1970s. The majority of SLE patients demonstrate evidence of type I IFN pathway activation; however, studies attempting to address the relationship between type I IFN signature and SLE disease activity have yielded conflicting results. In addition to type I IFNs, type II and III IFNs may overlap and also contribute to the IFN signature. Different genetic backgrounds lead to overproduction of type I IFNs in SLE and contribute to the breakdown of peripheral tolerance by activation of antigen-presenting myeloid dendritic cells, thus triggering the expansion and differentiation of autoreactive lymphocytes. The consequence of the continuous stimulation of the immune system is manifested in different organ systems typical of SLE (e.g., mucocutaneous and cardiovascular involvement). After the discovery of the type I IFN signature, a number of different strategies have been developed to downregulate the IFN system in SLE patients, finally leading to the successful trial of anifrolumab, the second biologic to be approved for the treatment of SLE in 10 years. In this review, we will discuss the bench to bedside translation of the type I IFN pathway and put forward some issues that remain unresolved when selecting SLE patients for treatment with biologics targeting type I IFNs.

Anifrolumab: First Approval

Anifrolumab (anifrolumab-fnia; Saphnelo^™) is a monoclonal antibody antagonist of the type 1 interferon receptor (IFNAR). It is being developed by AstraZeneca (under license from Medarex, now Bristol-Myers Squibb) for the treatment of autoimmune disorders, including systemic lupus erythematosus (SLE) and lupus nephritis, the underlying pathogenesis of which involves type 1 interferon. In July 2021, intravenous anifrolumab was approved in the USA for the treatment of adult patients with moderate to severe SLE who are receiving standard therapy. Anifrolumab (intravenous or subcutaneous) continues to be assessed in clinical studies in SLE in various countries, and the intravenous formulation is under regulatory review in the EU and Japan. This article summarizes the milestones in the development of anifrolumab leading to this first approval for the treatment of moderate to severe SLE.

Multiscale pharmacokinetic modeling of systemic exposure of subcutaneously injected biotherapeutics

Subcutaneously injected formulations have been developed for many biological products including monoclonal antibodies (mAbs). A knowledge gap nonetheless remains regarding the absorption and catabolism mechanisms and kinetics of a large molecule at the administration site. A multiscale pharmacokinetic (PK) model was thus developed by coupling multiphysics simulations of subcutaneous (SC) absorption kinetics with whole-body pharmacokinetic (PK) modeling, bridged by consideration of the presystemic clearance by the initial lymph. Our local absorption simulation of SC-injected albumin enabled the estimation of its presystemic clearance and led to the whole-body PK modeling of systemic exposure. The local absorption rate of albumin was found to be influential on the PK profile. Additionally, nineteen mAbs were explored via this multiscale simulation and modeling framework. The computational results suggest that stability propensities of the mAbs are correlated with the presystemic clearance, and electrostatic charges in the complementarity-determining region influence the local absorption rate. Still, this study underscores a critical need to experimentally determine various biophysical characteristics of a large molecule and the biomechanical properties of human skin tissues.

Pharmacokinetics, pharmacodynamics, and safety of subcutaneous anifrolumab in patients with systemic lupus erythematosus, active skin disease, and high type I interferon gene signature: a multicentre, randomised, double-blind, placebo-controlled, phase 2 study

BACKGROUND

300 mg of intravenous anifrolumab every 4 weeks added to standard-of-care treatment for patients with systemic lupus erythematosus (SLE) reduced disease activity and glucocorticoid requirement in a previous phase 3 trial. Because patients might find subcutaneous administration more convenient than intravenous delivery, we aimed to evaluate the pharmacokinetics, pharmacodynamics, safety, and efficacy of subcutaneous anifrolumab in patients with SLE, active skin disease, and a high type I interferon gene signature.

METHODS

This multicentre, randomised, double-blind, placebo-controlled, phase 2 study was done at 12 hospitals and outpatient clinics in Hungary, South Korea, Poland, and the USA. Eligible patients were aged 18-70 years, and had SLE with high type I interferon gene signature and an activity score on the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI) of at least 10. Enrolled participants were randomly assigned (3:1:3:1) by use of a voice-web response system to receive either 150 mg of subcutaneous anifrolumab or corresponding placebo, or 300 mg of subcutaneous anifrolumab or corresponding placebo in addition to stable standard-of-care treatment. The study was double-blinded with respect to intervention but not dose, until 12 weeks. Doses of oral glucocorticoids were tapered after week 12. The primary pharmacokinetic endpoint was the serum concentration of anifrolumab based on the maximum concentration after the first dose and the minimum (trough) concentration before subsequent doses and was measured in all patients who received anifrolumab and had at least one quantifiable serum pharmacokinetics observation following the first dose. The primary pharmacodynamic endpoint was neutralisation of the type I interferon pharmacodynamic signature at week 12 and was assessed in all patients with a high type I interferon pharmacodynamics signature at baseline based on a 21-gene test. Safety was evaluated in the full analysis set, which included all patients who received at least one dose of anifrolumab. This trial is completed and is registered at ClinicalTrials.gov, NCT02962960.

FINDINGS

Between March 14, 2017, and Oct 26, 2017, 36 patients were randomly assigned to receive 150 mg of anifrolumab (n=14), 300 mg of anifrolumab (n=13), or placebo (n=9). Two patients in the anifrolumab 150 mg group were excluded from the pharmacodynamic analysis set (n=34). Ten (71%) of 14 patients in the anifrolumab 150 mg group, ten (77%) of 13 patients in the anifrolumab 300 mg group, and nine (100%) of the nine patients in the placebo group completed 52 weeks of treatment. At week 12, pre-dose mean trough serum concentrations of anifrolumab were more than dose proportional between the anifrolumab 150 mg group (19·82 μg/mL [SD 15·01]) and the anifrolumab 300 mg group (60·28 μg/mL [43·66]), and the pharmacokinetics were non-linear. At week 12, the median percentage neutralisation of the type I interferon gene signature was higher with 150 mg (88·0% [median absolute deviation 7·4]) and 300 mg (90·7% [3·3]) of anifrolumab than with placebo (18·5% [8·1]), and more patients in the anifrolumab 150 mg group and the anifrolumab 300 mg group than in the placebo group had neutralisation of 75% or more (eight [67%] of 12 vs ten [77%] of 13 vs one [11%] of nine). At least one adverse event was reported by 23 (85%) of 27 patients in the anifrolumab groups and by seven (78%) of nine patients in the placebo group; most adverse events were of mild-to-moderate severity. Serious adverse events were reported in six (22%) of 27 patients in the anifrolumab groups (four patients in the 150 mg group and two in the 300 mg group). No serious adverse events were reported in the placebo group. Herpes zoster infection was reported by three (11%) of 27 patients in the anifrolumab groups and by one (11%) of nine patients in the placebo group. There were no treatment-related deaths.

INTERPRETATION

Anifrolumab, administered subcutaneously every 2 weeks to patients with SLE and moderate-to-severe skin manifestations, had non-linear pharmacokinetics that were more than dose proportional, and neutralised the type I interferon gene signature in a dose-dependent manner. The safety profile was consistent with previous studies of intravenous anifrolumab, supporting the continued development of anifrolumab as a subcutaneously administered therapy for patients with SLE.

FUNDING

AstraZeneca.

Anifrolumab, a monoclonal antibody to the type I interferon receptor subunit 1, for the treatment of systemic lupus erythematosus: an overview from clinical trials

Chronic activation of the type I interferon (IFN) pathway plays a critical role in systemic lupus erythematosus (SLE) pathogenesis. Anifrolumab is a human monoclonal antibody to the type I IFN receptor subunit 1, which blocks the action of type I IFNs. Two phase 3 studies (TULIP-1 and TULIP-2) and a phase 2b study (MUSE) provide substantial evidence for the efficacy and safety of anifrolumab for moderately to severely active SLE. In all three studies, monthly intravenous anifrolumab 300 mg was associated with treatment differences >16% compared with placebo at Week 52 in British Isles Lupus Assessment Group-based Composite Lupus Assessment response rates. The combined data across a range of other clinically significant endpoints (e.g. oral corticosteroid reduction, improved skin disease, flare reduction) further support the efficacy of anifrolumab for SLE treatment. The safety profile of anifrolumab was generally similar across all studies; serious adverse events occurred in 8-16% and 16-19% of patients receiving anifrolumab and placebo, respectively. Herpes zoster incidence was greater with anifrolumab (≤7%) vs placebo (≤2%). Evidence from these clinical trials suggests that in patients with active SLE, anifrolumab is superior to placebo in achieving composite endpoints of disease activity response and oral corticosteroid reduction.

Type I interferon antagonists in clinical development for lupus

INTRODUCTION

Systemic lupus erythematosus (SLE) is a severe chronic and incurable autoimmune disease. Treatment includes glucocorticoids and immunosuppressants which typically result in partial responses, and hence there is a great need for new therapies. The type I interferon (IFN) pathway is activated in more than 50% of SLE patients, and it is strongly implicated as a pathogenic factor in SLE.

AREAS COVERED

We searched the literature using 'SLE and interferon antagonists' as search terms. This identified a number of therapeutics that have entered clinical development targeting type I IFN in SLE. These include monoclonal antibodies against type I IFN cytokines and a kinoid vaccination strategy to induce anti-IFN antibodies.

EXPERT OPINION

Type I IFN antagonists have had some success, but many molecules have not progressed to phase III. These varied results are likely attributed to the multiple concurrent cytokine abnormalities present in SLE, the imprecise nature of the IFN signature as a readout for type I IFN and difficulties with clinical trials such as background medication use and diffuse composite disease activity measures. Despite these challenges, it seems likely that a type I IFN antagonist will come to clinical utility for SLE given the large unmet need and the recent phase III success with anifrolumab.

Anifrolumab in systemic lupus erythematosus: current knowledge and future considerations

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that is potentially life-threatening and can affect any organ. The complex pathogenesis and heterogeneity of the disease, among other factors, present significant challenges in developing new therapies. Knowledge gained over many years has implicated type I interferon (IFN) in the pathogenesis of SLE and anti-IFN therapies hold promise as a much-needed future treatment for SLE. Anifrolumab, a human monoclonal antibody against the type I IFN receptor, has recently been evaluated in two Phase III clinical trials for the treatment of moderate-to-severe SLE. Here, we review the clinical efficacy and safety of anifrolumab and discuss the potential challenges in determining the optimal SLE patient subgroup for treatment.

Pathogenic Role of Type I Interferons in HIV-Induced Immune Impairments in Humanized Mice

PURPOSE OF REVIEW

Recent findings on the critical pathogenic role of type 1 interferons (IFN-I) in HIV-1 persistence in humanized mice suggest that inhibiting IFN-I signaling transiently will reverse HIV-induced inflammatory diseases and rescue anti-HIV immunity to control HIV-1 reservoirs.

RECENT FINDINGS

In both humanized mice and in monkeys, IFN-I signaling is functionally defined to play an important role in suppressing early HIV-1 and SIV infection. During persistent infection in humanized mice, however, IFN-I signaling is revealed to induce T cell depletion and impairment. Interestingly, in HIV-infected mice with effective combination antiretroviral therapy (cART), blocking IFN-I signaling reverses HIV-induced inflammation, rescues anti-HIV T cells, and reduces HIV-1 reservoirs. These findings functionally define the role of IFN-I in HIV-1 reservoir persistence and suggest that blocking IFN-I signaling will provide a novel therapeutic strategy to (i) reverse inflammation-associated diseases in HIV patients under cART, (ii) rescue host anti-HIV immunity, and (iii) reduce or control HIV-1 reservoirs.

Understanding the Monoclonal Antibody Disposition after Subcutaneous Administration using a Minimal Physiologically based Pharmacokinetic Model

PURPOSE

Monoclonal antibodies (mAbs) are commonly administered by subcutaneous (SC) route. However, bioavailability is often reduced after SC administration. In addition, the sequential transfer of mAbs through the SC tissue and lymphatic system is not completely understood. Therefore, major objectives of this study were a) To understand absorption of mAbs via the lymphatic system after SC administration using physiologically based pharmacokinetic (PBPK) modeling, and b) to demonstrate application of the model for prediction of SC pharmacokinetics (PK) of mAbs.

METHODS

A minimal PBPK model was constructed using various physiological parameters related to the SC injection site and lymphatic system. The remainder of the body organs were represented using a 2-compartment model (central and peripheral compartments), with parameters derived from available intravenous (IV) PK data. The IV and SC clinical PK data of a total of 10 mAbs were obtained from literature. The SC PK data were used to estimate the lymphatic trunk-lymph node (LN) clearance.

RESULTS

The mean estimated lymphatic trunk-LN clearance obtained from 37 SC PK profiles of mAbs was 0.00213 L/h (0.001332 to 0.002928, 95% confidence intervals). The estimated lymphatic trunk-LN clearance was greater for the mAbs with higher isoelectric point (pI). In addition, the estimated clearance increased with decrease in the bioavailability.

CONCLUSION

The minimal PBPK model identified SC injection site lymph flow, afferent and efferent lymph flows, and volumes associated with the SC injection site, lymphatic capillaries and lymphatic trunk-LN as important physiological parameters governing the absorption of mAbs after SC administration. The model may be used to predict PK of mAbs using the relationship of lymphatic trunk-LN clearance and the pI. In addition, the model can be used as a bottom platform to incorporate SC and lymphatic in vitro clearance data for mAb PK prediction in the future.

Spotlight on anifrolumab and its potential for the treatment of moderate-to-severe systemic lupus erythematosus: evidence to date

Previous reports have described the appearance of systemic lupus erythematosus (SLE) cases following interferon-α (IFN-α) therapy, IFN-regulated gene expression is significantly increased in SLE, and an association between SLE and gene variants belonging to IFN downstream pathways has been shown. Based on this, targeting of IFN and of their signaling pathways has appeared to be interesting developments within the field of SLE therapy. Different specific type I IFN antagonists have been studied in clinical trials and some of those have already reached Phase III. A potential approach would be to target IFN receptors rather than IFN themselves. Anifrolumab (previously MEDI-546) is a fully human monoclonal antibody (Ab) that binds to subunit 1 of the type I IFN receptor (IFNAR1), blocking the action of different type I IFNs (IFN-α, IFN-β and IFN-ω). This drug has been assessed in 11 clinical studies: 9 in SLE, 1 in systemic sclerosis and 1 in rheumatoid arthritis. In SLE, clinical development reached Phase I for 1 study and Phases II and III for 5 and 3 trials, respectively. The Phase IIb, randomized control trial (RCT), double-blind, placebo-controlled study of adults with moderate-to-severe SLE (MUSE trial) showed positive results on the composite primary endpoint SRI-4. Greater efficacy was seen in patients with high baseline IFN gene signature compared with those with low baseline IFN gene signature. Anifrolumab also demonstrated promising results on cutaneous and arthritic manifestations, especially among patients with a high IFN gene signature. The pivotal Treatment of Uncontrolled Lupus via the Interferon IFN Pathway (TULIP 1 and 2 studies are now completed. In August 2018, the promoter announced that the TULIP 1 Phase III trial did not reach its primary endpoint. The release of the completed but not yet published Phase II studies and of the TULIP pivotal trials results will further inform us on the actual therapeutic potential of anifrolumab.

Safety and tolerability of anifrolumab, a monoclonal antibody targeting type I interferon receptor, in Japanese patients with systemic lupus erythematosus: A multicenter, phase 2, open-label study

Objectives: This study evaluated the safety and tolerability of anifrolumab, a monoclonal antibody targeting the type I interferon (IFN) receptor, in Japanese patients with moderate-to-severe systemic lupus erythematosus (SLE).Methods: In this open-label, phase 2, dose-escalation study, patients received intravenous (IV) anifrolumab 100, 300, or 1000 mg every 4 weeks from days 29 to 337 (Stage 1). Patients who completed Stage 1 continued anifrolumab 300 mg every 4 weeks for 156 weeks (Stage 2). The primary objective was to evaluate the safety of anifrolumab for 48 weeks (Stage 1) and 156 weeks (Stage 2). The pharmacokinetics and pharmacodynamics of anifrolumab were also assessed.Results: Of 20 patients enrolled in Stage 1, 17 received IV anifrolumab 100 mg (n = 6), 300 mg (n = 5), or 1000 mg (n = 6). Adverse events (AE) and serious AE (SAE) incidences were similar between dose cohorts. SAEs occurred in 41% (Stage 1) and 33% (Stage 2) of patients; AEs leading to discontinuation occurred in 24% (Stage 1) and 22% (Stage 2) of patients. Anifrolumab had non-linear pharmacokinetics after the first and last dose and dose-dependently suppressed the IFN gene signature.Conclusion: Anifrolumab was well tolerated among Japanese patients with moderate-to-severe SLE.