Does Extended Interval Dosing Natalizumab Preserve Effectiveness in Multiple Sclerosis? A 7 Year-Retrospective Observational Study

Prospective trial of natalizumab personalised extended interval dosing by therapeutic drug monitoring in relapsing-remitting multiple sclerosis (NEXT-MS)

BACKGROUND

Extended interval dosing (EID) of natalizumab is a promising strategy to optimise treatment in multiple sclerosis (MS). Personalised EID by therapeutic drug monitoring can enable further extension of treatment intervals.

METHODS

The NEXT-MS trial is an investigator-initiated prospective phase IV non-randomised study. Adults with a diagnosis of relapsing-remitting MS who received ≥6 natalizumab infusions were included in three groups: personalised EID with a target drug trough concentration of 10 µg/mL (EID10), an exploratory group of personalised EID with a target of 5 µg/mL (EID5) and standard interval dosing (SID) of 4 weeks. The primary outcome is radiological disease activity (new/newly enlarged T2 lesions) comparing the EID10 group to a historical cohort of SID (HSID).

RESULTS

Results of the first phase of the NEXT-MS trial are reported here (n=376) as the study will continue with an amended protocol. In the EID10 group (n=251), incidence rate of radiological activity was 10.0 per 1000 person-years, which was non-inferior to the HSID cohort (24.7 per 1000 person-years (n=87), incidence rate difference 14.7, 90% CI -4.5 to 34.0). Incidence rate of radiological activity was 10.0 per 1000 person-years in the EID5 group (n=65), and 47.0 per 1000 person-years in the SID group (n=60). Serum neurofilament light levels did not increase over time within the EID groups. There were no cases of progressive multifocal leukoencephalopathy.

CONCLUSIONS

MS disease activity is adequately controlled with personalised natalizumab EID. Interval extension to a drug trough concentration of 5 µg/mL is likely a safe target to extend natalizumab treatment intervals >6 weeks.

TRIAL REGISTRATION NUMBER

NCT04225312.

Drug-Induced Progressive Multifocal Leukoencephalopathy (PML): A Systematic Review and Meta-Analysis

INTRODUCTION

Progressive multifocal leukoencephalopathy (PML) was first described among patients affected by hematological or solid tumors. Following the human immunodeficiency virus (HIV) epidemic, people living with HIV have represented most cases for more than a decade. With the diffusion of highly active antiretroviral therapy, this group progressively decreased in favor of patients undergoing treatment with targeted therapy/immunomodulators. In this systematic review and meta-analysis, the objective was to assess which drugs are most frequently related to PML development, and report the incidence of drug-induced PML through a meta-analytic approach.

METHODS

The electronic databases MEDLINE, EMBASE, ClinicalTrials.gov, Web of Science and the Canadian Agency for Drugs and Technologies in Health Database (CADTH) were searched up to May 10, 2022. Articles that reported the risk of PML development after treatment with immunomodulatory drugs, including patients of both sexes under the age of 80 years, affected by any pathology except HIV, primary immunodeficiencies or malignancies, were included in the review. The incidence of drug-induced PML was calculated based on PML cases and total number of patients observed per 100 persons and the observation time. Random-effect metanalyses were conducted for each drug reporting pooled incidence with 95% confidence intervals (CI) and median (interquartile range [IQR]) of the observation time. Heterogeneity was measured by I2 statistics. Publication bias was examined through funnel plots and Egger's test.

RESULTS

A total of 103 studies were included in the systematic review. In our analysis, we found no includible study reporting cases of PML during the course of treatment with ocrelizumab, vedolizumab, abrilumab, ontamalimab, teriflunomide, daclizumab, inebilizumab, basiliximab, tacrolimus, belimumab, infliximab, firategrast, disulone, azathioprine or danazole. Dalfampridine, glatiramer acetate, dimethyl fumarate and fingolimod show a relatively safe profile, although some cases of PML have been reported. The meta-analysis showed an incidence of PML cases among patients undergoing rituximab treatment for multiple sclerosis (MS) of 0.01 cases/100 persons (95% CI - 0.08 to 0.09; I2 = 20.4%; p = 0.25) for a median observation period of 23.5 months (IQR 22.1-42.1). Treatment of MS with natalizumab carried a PML risk of 0.33 cases/100 persons (95% CI 0.29-0.37; I2 = 50%; p = 0.003) for a median observation period of 44.1 months (IQR 28.4-60) and a mean number of doses of 36.3 (standard deviation [SD] ± 20.7). When comparing data about patients treated with standard interval dosing (SID) and extended interval dosing (EID), the latter appears to carry a smaller risk of PML, that is, 0.08 cases/100 persons (95% CI 0.0-0.15) for EID versus 0.3 cases/100 persons (95% CI 0.25-0.34) for SID.

CONCLUSIONS

A higher risk of drug-related PML in patients whose immune system is not additionally depressed by means of neoplasms, HIV or concomitant medications is found in the neurological field. This risk is higher in MS treatment, and specifically during long-term natalizumab therapy. While this drug is still routinely prescribed in this field, considering the efficacy in reducing MS relapses, in other areas it could play a smaller role, and be gradually replaced by other safer and more recently approved agents.

Safety and efficacy of extended versus standard interval dosing of natalizumab in multiple sclerosis patients: a systematic review and meta-analysis

BACKGROUND

Multiple sclerosis (MS) is a chronic inflammatory, immune-mediated disease affecting the central nervous system. Natalizumab, an FDA-approved monoclonal antibody for MS, has been explored for its off-label extended interval dosing (EID), suggesting a potential reduction in the risk of progressive multifocal leukoencephalopathy (PML) compared to standard interval dosing (SID). Our objective was to assess the efficacy and safety of EID in comparison to SID for natalizumab treatment in patients with MS.

METHODS

We searched PubMed, Embase, WOS, Scopus, Ovid, Science Direct, Clinical trials.gov, and Cochrane Library. Our assessed outcomes were clinical relapses, MRI activity, change in expanded disability status scale [EDSS], and the risk of PML. The EID group was defined as 5 to 8 weeks [EID (Q5-8W)]. The analysis was conducted using RevMan ver. 5.4. The effect estimates were presented as a risk ratio [RR] or mean difference with 95% confidence intervals [CI] using SID group as the reference for comparisons.

RESULTS

Fourteen studies met our inclusion criteria: 2 RCTs, 1 switched single-arm trial, and 12 observational studies. No significant differences were found in all efficacy outcomes of interest. Risk of clinical relapses [RR = 0.90, (95%CI 0.80, 1.02)], risk of new or newly enlarging T2 hyperintense MRI lesions [RR = 0.78, (95%CI 0.59, 1.04)], risk gadolinium enhancing lesions [RR = 1.30, (95%CI 0.98, 1.72)], change in EDSS [MD = 0.09 (95%CI - 0.57, 0.76)], risk of PML [RR = 1.09, 95%CI (0.24, 4.94)].

CONCLUSION

In summary, our meta-analysis indicates that natalizumab maintains its effectiveness under extended interval dosing [up to 8 weeks], presenting comparable risks for clinical relapses, MRI lesions, EDSS, and PML. Caution is advised given study limitations and heterogeneity. Robust conclusions necessitate well-designed high-quality prospective studies.

Treatment modifiers across different regimens of natalizumab treatment in MS: An Italian real-world experience

Despite its widespread use in clinical practice, the effectiveness of natalizumab extended interval dosing (EID) adopted from treatment start across different treatment intervals and individual modifiers (body mass index - BMI) is still under-investigated. Here, seven-hundred and forty-five multiple sclerosis (MS) patients, exposed to natalizumab for 3.30 ​± ​1.34 years, were retrospectively enrolled in an observational multicenter study. After stratifying patients in EID or standard interval dosing (SID), we assessed differences in time to relapse, MRI activity and Expanded Disability Status Scale (EDSS) progression. The primary analysis was conducted on patients exposed to EID interval from 5 weeks and 1 day to 7 weeks, while a secondary analysis included also EID periods up to 8 weeks. An additional analysis explored the impact of BMI. No differences in time to first relapse, time to radiological activity, time to EDSS progression or time to EDA (evidence of disease activity) were detected between SID and EID group (EID interval from 5 weeks to 1 day to 7 weeks). When including EID periods from 7 weeks and 1 day to 8 weeks, the EID group showed a trend towards higher risk of experience clinical relapses than the SID group. A higher EDA risk was also identified in EID patients with BMI above median. In conclusion, a higher risk of relapses seems to occur for EID above 7 weeks. Independently from the EID scheme adopted, higher BMI increases the risk of EDA in these patients.

Long-term outcome of natalizumab-associated progressive multifocal leukoencephalopathy in Austria: a nationwide retrospective study

BACKGROUND/OBJECTIVE

The use of natalizumab (NAT) in multiple sclerosis (MS) may be complicated by progressive multifocal leukoencephalopathy (PML), a rare and life-threatening opportunistic brain infection. We aimed to analyze the course of MS after PML recovery together with the long-term outcome of NAT-associated PML (NAT-PML) in Austria.

METHODS

Retrospective study based on identification of cases in the nationwide Austrian MS treatment registry (AMSTR) and MS centers with review of patient records. The expanded disability status scale (EDSS) was used to measure neurological disability and outcome.

RESULTS

As of December 2022, we identified 15 NAT-PML cases in Austria; only 20% occurred after 2016, when increased vigilance commenced. Two patients did not survive acute PML, and an additional patient died five years later, yielding a mortality rate of 20%. Seizures occurred exclusively in patients with pronounced EDSS increase. Gadolinium (Gd)-enhancement on brain magnetic resonance imaging (MRI) on PML suspicion was associated with minor changes of post-PML neurological disability. Long-term follow-up of up to 132 months (median 76 months) was available in 11/15. The overall median EDSS increased from 3.5 at pre-PML to 6.5 at the last assessment. Regarding inflammatory MS-related disease activity during the observation period, one single individual experienced an MS relapse and another patient had two Gd-enhancing brain lesions. Three patients converted to progressive MS within three years from PML and the EDSS further increased in 6/11.

CONCLUSIONS

The number of NAT-PML cases is decreasing over time. While many patients accumulated severe persistent neurological deficits compared to pre-PML, inflammatory MS-related disease activity after PML recovery was rare.

Lessons learned after 20 years of real-world experience with natalizumab

BACKGROUND

While natalizumab (NTZ) is an effective therapy for multiple sclerosis (MS), it is associated with an increased risk of progressive multifocal leukoencephalopathy (PML). After 20 years (2002-2022) of experience with NTZ at our center, we observed no cases of PML.

OBJECTIVES

We evaluated the likelihood of experiencing PML in a subset of our treatment cohort, as well as reviewed treatment practices at our center that may mitigate PML risk.

METHODS

For this retrospective study, we reviewed patient characteristics, treatment practices, and clinical and MRI findings in patients receiving NTZ from 2006 to 2020. Observation of no PML cases was compared to the global and US PML incidences, and to the expected incidence based on published risk estimates.

RESULTS

766 patients were evaluated. The number of NTZ infusions received ranged from 1 to 126, with a mean of 28. Patients received neurological examination prior to each infusion, which sometimes resulted in a pause in therapy to rule out PML if clinical worsening occurred. Extended interval dosing (EID) was the overall dosing schedule for 31% of patients. EID did not result in higher rates of radiological disease worsening than standard interval dosing (SID) patients. Depending on the analysis conducted, the finding of 0 PML cases in our cohort ranged from slightly unexpected to slightly expected.

CONCLUSIONS

The utilization of EID as well as regular clinical monitoring of patients may have lowered PML risk while still maintaining NTZ efficacy.

High levels of endothelial ICAM-1 prohibit natalizumab mediated abrogation of CD4+ T cell arrest on the inflamed BBB under flow in vitro

INTRODUCTION

The humanized anti-α4 integrin blocking antibody natalizumab (NTZ) is an effective treatment for relapsing-remitting multiple sclerosis (RRMS) that is associated with the risk of progressive multifocal leukoencephalopathy (PML). While extended interval dosing (EID) of NTZ reduces the risk for PML, the minimal dose of NTZ required to maintain its therapeutic efficacy remains unknown.

OBJECTIVE

Here we aimed to identify the minimal NTZ concentration required to inhibit the arrest of human effector/memory CD4⁺ T cell subsets or of PBMCs to the blood-brain barrier (BBB) under physiological flow in vitro.

RESULTS

Making use of three different human in vitro BBB models and in vitro live-cell imaging we observed that NTZ mediated inhibition of α4-integrins failed to abrogate T cell arrest to the inflamed BBB under physiological flow. Complete inhibition of shear resistant T cell arrest required additional inhibition of β2-integrins, which correlated with a strong upregulation of endothelial intercellular adhesion molecule (ICAM)-1 on the respective BBB models investigated. Indeed, NTZ mediated inhibition of shear resistant T cell arrest to combinations of immobilized recombinant vascular cell adhesion molecule (VCAM)-1 and ICAM-1 was abrogated in the presence of tenfold higher molar concentrations of ICAM-1 over VCAM-1. Also, monovalent NTZ was less potent than bivalent NTZ in inhibiting T cell arrest to VCAM-1 under physiological flow. In accordance with our previous observations ICAM-1 but not VCAM-1 mediated T cell crawling against the direction of flow.

CONCLUSION

Taken together, our in vitro observations show that high levels of endothelial ICAM-1 abrogate NTZ mediated inhibition of T cell interaction with the BBB. EID of NTZ in MS patients may thus require consideration of the inflammatory status of the BBB as high levels of ICAM-1 may provide an alternative molecular cue allowing for pathogenic T cell entry into the CNS in the presence of NTZ.

An Elusive Target: Inhibitors of JC Polyomavirus Infection and Their Development as Therapeutics for the Treatment of Progressive Multifocal Leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease caused by infection with JC Polyomavirus (JCPyV). Despite the identification of the disease and isolation of the causative pathogen over fifty years ago, no antiviral treatments or prophylactic vaccines exist. Disease onset is usually associated with immunosuppression, and current treatment guidelines are limited to restoring immune function. This review summarizes the drugs and small molecules that have been shown to inhibit JCPyV infection and spread. Paying attention to historical developments in the field, we discuss key steps of the virus lifecycle and antivirals known to inhibit each event. We review current obstacles in PML drug discovery, including the difficulties associated with compound penetrance into the central nervous system. We also summarize recent findings in our laboratory regarding the potent anti-JCPyV activity of a novel compound that antagonizes the virus-induced signaling events necessary to establish a productive infection. Understanding the current panel of antiviral compounds will help center the field for future drug discovery efforts.

The Oxindole GW-5074 Inhibits JC Polyomavirus Infection and Spread by Antagonizing the MAPK-ERK Signaling Pathway

JC polyomavirus (JCPyV) is a ubiquitous, double-stranded DNA virus that causes the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML) in immunocompromised patients. Current treatments for PML are limited to immune reconstitution, and no effective antivirals exist. In this report, we show that the oxindole GW-5074 (3-(3,5-dibromo-4-hydroxybenzylidene)-5-iodoindolin-2-one) reduces JCPyV infection in primary and immortalized cells. This compound potently inhibits virus spread, which suggests that it could control infection in PML patients. We demonstrate that GW-5074 inhibits endogenous ERK phosphorylation, and that JCPyV infection in GW-5074-treated cells cannot be rescued with ERK agonists, which indicates that the antiviral mechanism may involve its antagonistic effects on MAPK-ERK signaling. Importantly, GW-5074 exceeds thresholds of common pharmacological parameters that identify promising compounds for further development. This MAPK-ERK antagonist warrants further investigation as a potential treatment for PML. IMPORTANCE Human polyomaviruses, such as JCPyV and BKPyV, cause significant morbidity and mortality in immunocompromised or immunomodulated patients. There are no treatments for polyomavirus-induced diseases other than restoration of immune function. We discovered that the oxindole GW-5074 potently inhibits infection by both JCPyV and BKPyV. Further optimization of this compound could result in the development of antiviral therapies for polyomavirus-induced diseases.

Switch to ocrelizumab in MS patients treated with natalizumab in extended interval dosing at high risk of PML: A 96-week follow-up pilot study

We aimed to assess the long-term safety and effectiveness of ocrelizumab in a cohort of patients with multiple sclerosis (MS) at high risk of progressive multifocal leukoencephalopathy (PML), previously treated with natalizumab in extending interval dosing (EID), who switched to ocrelizumab and to compare them with patients who continued EID-natalizumab. Thirty MS patients previously treated with natalizumab in EID (every 8 weeks) were included in this observational retrospective cohort study. Among them, 17 patients were switched to ocrelizumab and 13 continued with EID-natalizumab. Except for the John Cunningham virus (JCV) index, no significant differences were detected between both groups. Main outcome measures included: annualized relapse rate (ARR), radiological activity, disability progression, and the NEDA-3 index. Patients were followed for 96 weeks. The median washout period in ocrelizumab-switchers was 6 weeks. Among them, AAR and radiological activity during follow-up were 0.03, without significant differences in comparison with the previous period on natalizumab-EID. The comparison between ocrelizumab-switchers and patients continuing on EID-natalizumab showed no significant differences in AAR, radiological activity, or disability progression. However, the proportion of patients maintaining a NEDA-3 status in week 96 was slightly superior among ocrelizumab-switchers (94 vs 69%). No serious adverse events were observed in any group. In conclusion, switching from EID-natalizumab to ocrelizumab can be considered as a therapeutic option, particularly in patients with MS at high risk of PML, to mitigate the risks of both PML and disease reactivation.

Specific Aspects of Immunotherapy for Multiple Sclerosis in Switzerland—A Structured Commentary, Update 2022

Multiple sclerosis (MS), particularly relapsing MS (RMS), has become a treatable disease in recent decades, and immunotherapies are now able to influence long-term disease course. A wide range of disease-modifying drugs are available, which makes the choice of therapy in individual cases considerably more complex. Due to specific regulatory aspects (partly diverging approvals by Swissmedic compared to the European Medicines Agency (EMA), and an independent evaluation process for the Federal Office of Public Health (FOPH) specialities list (SL)), we issued a consensus recommendation regarding specific aspects of immunotherapy for MS in Switzerland in 2019. Here, we present revised recommendations with an update on newly approved drugs and new safety aspects, also in reference to the risk of COVID-19 infection and vaccination.

Natalizumab extended-interval dosing in multiple sclerosis to mitigate progressive multifocal leukoencephalopathy risk: initial study evidence and real-world experience

The high efficacy of natalizumab in the treatment of relapsing-remitting multiple sclerosis (MS) is without controversy. Indeed, effective disease control was not only demonstrated in the pivotal trials but has been corroborated impressively in real-world observations. This monoclonal IgG4 antibody blocks the α4β1 integrin-mediated leukocyte-endothelial interaction and thereby inhibits the migration of immune cells to the brain parenchyma. However, treatment with natalizumab carries the risk of progressive multifocal leukoencephalopathy (PML). This potentially lethal side effect is a significant limitation for treatment initiation and long-term therapy. Natalizumab is given intravenously or subcutaneously in the standard dose of 300 mg every 4 weeks, allowing drug concentrations at levels that ensure continuous α4β1 integrin receptor saturation on the surface of immune cells. Extended-interval dosing (EID) is an emerging treatment approach that aims to mitigate the natalizumab-related PML risk by prolonging the standard infusion intervals to 6 weeks or even more. This treatment approach may abrogate the PML risk due to improved immune surveillance within the central nervous system while maintaining clinical efficacy. Moreover, even an individual interval dosing can be envisioned based on the availability of a biomarker that is capable of monitoring both safety and efficacy aspects. This review summarizes the early and encouraging evidence for EID from observational and randomized-controlled trials and discusses current limitations and upcoming challenges for introducing a tailored treatment approach.

Comparison of switching to 6-week dosing of natalizumab versus continuing with 4-week dosing in patients with relapsing-remitting multiple sclerosis (NOVA): a randomised, controlled, open-label, phase 3b trial

BACKGROUND

Treatment with natalizumab once every 4 weeks is approved for patients with relapsing-remitting multiple sclerosis, but is associated with a risk of progressive multifocal leukoencephalopathy. Switching to extended-interval dosing is associated with lower progressive multifocal leukoencephalopathy risk, but the efficacy of this approach is unclear. We aimed to assess the safety and efficacy of natalizumab once every 6 weeks compared with once every 4 weeks in patients with relapsing-remitting multiple sclerosis.

METHODS

We did a randomised, controlled, open-label, phase 3b trial (NOVA) at 89 multiple sclerosis centres across 11 countries in the Americas, Europe, and Western Pacific. Included participants were aged 18-60 years with relapsing-remitting multiple sclerosis and had been treated with intravenous natalizumab 300 mg once every 4 weeks with no relapses for at least 12 months before randomisation, with no missed doses in the previous 3 months. Participants were randomly assigned (1:1), using a randomisation sequence generated by the study funder and contract personnel with interactive response technology, to switch to natalizumab once every 6 weeks or continue with once every 4 weeks. The centralised MRI reader, independent neurology evaluation committee, site examining neurologists, site backup examining neurologists, and site examining technicians were masked to study group assignments. The primary endpoint was the number of new or newly enlarging T2 hyperintense lesions at week 72, assessed in all participants who received at least one dose of assigned treatment and had at least one postbaseline MRI, relapse, or neurological examination or efficacy assessment. Missing primary endpoint data were handled under prespecified primary and secondary estimands: the primary estimand included all data, regardless of whether participants remained on the assigned treatment; the secondary estimand classed all data obtained after treatment discontinuation or study withdrawal as missing. Safety was assessed in all participants who received at least one dose of study treatment. Study enrolment is closed and an open-label extension study is ongoing. This study is registered with EudraCT, 2018-002145-11, and ClinicalTrials.gov, NCT03689972.

FINDINGS

Between Dec 26, 2018, and Aug 30, 2019, 605 patients were assessed for eligibility and 499 were enrolled and assigned to receive natalizumab once every 6 weeks (n=251) or once every 4 weeks (n=248). After prespecified adjustments for missing data, mean numbers of new or newly enlarging T2 hyperintense lesions at week 72 were 0·20 (95% CI 0·07-0·63) in the once every 6 weeks group and 0·05 (0·01-0·22) in the once every 4 weeks group (mean lesion ratio 4·24 [95% CI 0·86-20·85]; p=0·076) under the primary estimand, and 0·31 (95% CI 0·12-0·82) and 0·06 (0·01-0·31; mean lesion ratio 4·93 [95% CI 1·05-23·20]; p=0·044) under the secondary estimand. Two participants in the once every 6 weeks group with extreme new or newly enlarging T2 hyperintense lesion numbers (≥25) contributed most of the excess lesions. Adverse events occurred in 194 (78%) of 250 participants in the once every 6 weeks group and 190 (77%) of 247 in the once every 4 weeks group, and serious adverse events occurred in 17 (7%) and 17 (7%), respectively. No deaths were reported. There was one case of asymptomatic progressive multifocal leukoencephalopathy (without clinical signs) in the once every 6 weeks group, and no cases in the once every 4 weeks group; 6 months after diagnosis, the participant was without increased disability and remained classified as asymptomatic.

INTERPRETATION

We found a numerical difference in the mean number of new or newly enlarging T2 hyperintense lesions at week 72 between the once every 6 weeks and once every 4 weeks groups, which reached significance under the secondary estimand, but interpretation of statistical differences (or absence thereof) is limited because disease activity in the once every 4 weeks group was lower than expected. The safety profiles of natalizumab once every 6 weeks and once every 4 weeks were similar. Although this trial was not powered to assess differences in risk of progressive multifocal leukoencephalopathy, the occurrence of the (asymptomatic) case underscores the importance of monitoring and risk factor consideration in all patients receiving natalizumab.

FUNDING

Biogen.

Monoclonal Antibodies in the Treatment of Relapsing Multiple Sclerosis: an Overview with Emphasis on Pregnancy, Vaccination, and Risk Management

Monoclonal antibodies have become a mainstay in the treatment of patients with relapsing multiple sclerosis (RMS) and provide some benefit to patients with primary progressive MS. They are highly precise by specifically targeting molecules displayed on cells involved in distinct immune mechanisms of MS pathophysiology. They not only differ in the target antigen they recognize but also by the mode of action that generates their therapeutic effect. Natalizumab, an [Formula: see text]4[Formula: see text]1 integrin antagonist, works via binding to cell surface receptors, blocking the interaction with their ligands and, in that way, preventing the migration of leukocytes across the blood-brain barrier. On the other hand, the anti-CD52 monoclonal antibody alemtuzumab and the anti-CD20 monoclonal antibodies rituximab, ocrelizumab, ofatumumab, and ublituximab work via eliminating selected pathogenic cell populations. However, potential adverse effects may be serious and can necessitate treatment discontinuation. Most importantly, those are the risk for (opportunistic) infections, but also secondary autoimmune diseases or malignancies. Monoclonal antibodies also carry the risk of infusion/injection-related reactions, primarily in early phases of treatment. By careful patient selection and monitoring during therapy, the occurrence of these potentially serious adverse effects can be minimized. Monoclonal antibodies are characterized by a relatively long pharmacologic half-life and pharmacodynamic effects, which provides advantages such as permitting infrequent dosing, but also creates disadvantages regarding vaccination and family planning. This review presents an overview of currently available monoclonal antibodies for the treatment of RMS, including their mechanism of action, efficacy and safety profile. Furthermore, we provide practical recommendations for risk management, vaccination, and family planning.

Updated Perspectives on the Challenges of Managing Multiple Sclerosis During Pregnancy

Multiple sclerosis (MS) is a chronic immune-mediated, inflammatory, and degenerative disease that is up to three times more frequent in young women. MS does not alter fertility and has no impact on fetal development, the course of pregnancy, or childbirth. The Pregnancy in Multiple Sclerosis Study in 1998 showed that pregnancy, mostly in untreated women, did not adversely affect MS, as disease activity decreased during pregnancy (although it significantly increased in the first trimester postpartum). These findings, together with the limited information available on the potential risks of fetal exposure to disease modifying treatments (DMTs), meant that women were advised to delay the onset of DMTs, stop them prior to conception, or, in case of unplanned pregnancy, discontinue them when pregnancy was confirmed. Now, many women with MS receive DMTs before pregnancy and, despite being considered a period of MS stability, up to 30% of patients could relapse in the first trimester postpartum. Factors associated with an increased risk of relapse and disability during pregnancy and postpartum include relapses before and during pregnancy, a greater disability at the time of conception, the occurrence of relapses after DMT cessation before conception, and the use of high-efficacy DMTs before conception, especially natalizumab or fingolimod. Strategies to prevent postpartum activity are needed in some patients, but consensus is lacking regarding the therapeutic strategies for women with MS of a fertile age. This, along with the increasing number of DMTs, means that the decision-making processes in aspects related to family planning and therapeutic strategies before, during, and after pregnancy are increasingly more complex. The purpose of this review is to provide an update on pregnancy-related issues in women with MS, including recommendations for counseling, general management, use of DMTs in pre-pregnancy, pregnancy, and postpartum periods, and breastfeeding-related aspects of DMTs.

Extended dosing of monoclonal antibodies in multiple sclerosis

Over the past two decades, treatment options for patients with multiple sclerosis (MS) have increased exponentially. In the current therapeutic landscape, "no evidence of MS disease activity" is within reach in many of our patients. Minimizing risks of complications, improving treatment convenience, and decreasing health care costs are goals that are yet to be reached. One way to optimize MS therapy is to implement personalized or extended interval dosing. Monoclonal antibodies are suitable candidates for personalized dosing (by therapeutic drug monitoring) or extended interval dosing. An increasing number of studies are performed and underway reporting on altered dosing intervals of anti-α₄β₁-integrin treatment (natalizumab) and anti-CD20 treatment (ocrelizumab, rituximab, and ofatumumab) in MS. In this review, current available evidence regarding personalized and extended interval dosing of monoclonal antibodies in MS is discussed with recommendations for future research and clinical practice.

Anti-drug antibodies to antibody-based therapeutics in multiple sclerosis

Multiple sclerosis is the major demyelinating autoimmune disease of the central nervous system. Relapsing MS can be treated by a number of approved monoclonal antibodies that currently target: CD20, CD25 (withdrawn), CD49d and CD52. These all target potentially pathogenic memory B cell subsets and perhaps functionally inhibit pathogenic T cell function. These consist of chimeric, humanized and fully human antibodies. However, despite humanization it is evident that all of these monoclonal antibodies can induce binding and neutralizing antibodies ranging from < 1% to over 80% within a year of treatment. Importantly, it is evident that monitoring these allow prediction of future treatment-failure in some individuals and treatment cessation and switching therefore potentially limiting disease breakthrough and disability accumulation. In response to the COVID-19 pandemic and the need to avoid hospitals, shortened infusion times and extended dose intervals have been implemented, importantly, subcutaneous delivery of alternative treatments or formulations have been developed to allow for home treatment. Therefore, hospital-based and remote monitoring of ADA could therefore be advantageous to optimize patient responses in the future.