Pharmacokinetics and Pharmacodynamics of Natalizumab 6-Week Dosing vs Continued 4-Week Dosing for Relapsing-Remitting Multiple Sclerosis.

BACKGROUND AND OBJECTIVES: Exposure to natalizumab, an efficacious treatment for relapsing-remitting multiple sclerosis (RRMS), is associated with increased risk of progressive multifocal leukoencephalopathy (PML). Compared with every-4-week (Q4W) dosing, extended-interval dosing of natalizumab is associated with decreased risk of PML. Clinical efficacy was maintained in the majority of patients switched to every-6-week (Q6W) dosing in the phase 3b NOVA clinical trial. In this article, we report pharmacokinetics (PK) and pharmacodynamics (PD) of Q6W vs Q4W dosing in NOVA. METHODS: In NOVA study Part 1, participants with RRMS (aged 18-60 years) and Expanded Disability Status Scale score <5.5, who were stable on IV natalizumab Q4W dosing for ≥12 months, were randomized to continue IV Q4W dosing or switched to IV Q6W dosing of natalizumab and followed for 72 weeks. Exploratory outcomes were measurements of trough serum natalizumab concentration, α4-integrin saturation, and soluble vascular cell adhesion molecule-1 (sVCAM-1) concentration. A mixed model of repeated measures was used to estimate mean treatment differences between groups. Patient-level PK and PD data were examined in those with relapse or radiologic disease activity. RESULTS: In NOVA, 486 (Q6W, n = 245; Q4W, n = 241) and 487 (Q6W, n = 246; Q4W, n = 241) participants were included in the PK and PD populations, respectively. Mean trough natalizumab concentrations ranged from 10 to 21 µg/mL (Q6W) and 33-38 µg/mL (Q4W), and mean α4-integrin saturation remained above 65.5% (Q6W) and above 77.9% (Q4W). In the Q6W group, mean sVCAM-1 levels increased 23.6% by week 24 and remained elevated throughout the study, while mean sVCAM-1 levels remained generally stable in the Q4W group. Most participants with T2 lesion activity or relapse activity, in either treatment arm, maintained trough natalizumab levels >10 µg/mL and trough α4-integrin saturation >50%. DISCUSSION: Compared with Q4W dosing, Q6W dosing was associated with a 60%-70% decrease in mean trough natalizumab levels and a 9%-16% decrease in mean α4-integrin saturation. At the patient level, neither natalizumab concentration nor α4-integrin saturation was consistently predictive of lesion or relapse activity, suggesting that trough natalizumab and α4-integrin saturation measurements should be interpreted with caution in clinical practice. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov, NCT03689972; EudraCT, 2018-002145-11. Submitted 2018-09-27. First patient enrolled: 2018-12-26. https://clinicaltrials.gov/study/NCT03689972.

A 2-stage model of heterogenous treatment effects for brain atrophy in multiple sclerosis utilizing the MS PATHS research network.

BACKGROUND: Two-stage models of heterogenous treatment effects (HTE) may advance personalized medicine in multiple sclerosis (MS). Brain atrophy is a relatively objective outcome measure that has strong relationships to MS prognosis and treatment effects and is enabled by standardized MRI. OBJECTIVES: To predict brain atrophy outcomes for patients initiating disease-modifying therapies (DMT) with different efficacies, considering the patients' baseline brain atrophy risk measured via brain parenchymal fraction (BPF). METHODS: Analyses included patients enrolled in the Multiple Sclerosis Partners Advancing Technology and Health Solutions (MS PATHS) network who started DMT and had complete baseline data and ≥ 6-month brain MRI follow-up. All brain MRIs were acquired using standardized acquisition sequences on Siemens 3T scanners. BPF change risk was derived by linear mixed effects models using baseline covariates. Model performance was assessed by predicted versus actual BPF change R2. Propensity score (PS) weighting was used to balance covariates between groups defined by DMT efficacy (high: natalizumab, alemtuzumab, ocrelizumab, and rituximab; moderate: dimethyl fumarate, fingolimod, and cladribine; low: teriflunomide, interferons, and glatiramer acetate). HTE models predicting 1 year change in BPF were built using a weighted linear mixed effects model with low-efficacy DMT as the reference. RESULTS: Analyses included 581 high-, 183 moderate-, and 106 low-efficacy DMT-treated patients. The mean and median number of brain MRI observations per treatment period were 2.9 and 3.0, respectively. Risk model performance R2=0.55. After PS weighting, covariate standardized mean differences were <10 %, indicating excellent balance across measured variables. Changes in BPF between baseline and follow-up were found to be statistically significant (p < 0.001), suggesting a pathological change. Patients with low brain atrophy risk had a similar outcome regardless of DMT selection. In patients with high brain atrophy risk, high- and moderate-efficacy DMTs performed similarly, while a 2-fold worse BPF change was predicted for patients selecting low-efficacy DMTs (p < 0.001). Similar results were observed in a sensitivity analysis adjusting for pseudoatrophy effects in a sub-population of patients treated with natalizumab. CONCLUSIONS: The relative benefit of selecting higher efficacy treatments may vary depending on patients' baseline brain atrophy risk. Poor outcomes are predicted in individuals with high baseline risk who are treated with low-efficacy DMTs.

Comparative efficacy of subcutaneous versus intravenous natalizumab on annualized relapse rate: A post-hoc analysis of the REFINE study.

BACKGROUND: The non-inferiority of the efficacy of subcutaneous (SC) vs intravenous (IV) administration of natalizumab (NTZ) once every 4 weeks in relapsing-remitting multiple sclerosis (RRMS) was recently demonstrated on the primary outcome of the REFINE study, i.e. MRI "combined unique active lesions number" (CUAL). To provide further evidence on the comparative efficacy of the two NTZ formulations, the effect of NTZ-SC vs NTZ-IV on annualized relapse rate (ARR) was investigated re-analysing the REFINE dataset. METHODS: Post-hoc analysis of the REFINE study dataset aimed at exploring the non-inferiority of the efficacy of NTZ-SC vs NTZ-IV on ARR, i.e. the main secondary outcome of the REFINE study. Robustness of the non-inferiority analysis on CUAL with respect to the presence of cases from the SC arm who received a rescue treatment, including NTZ-IV, was also assessed by sensitivity analyses. Three non-inferiority margins were selected, corresponding to 25 %, 33 %, and 50 % fractions of the effect size of NTZ-IV vs placebo observed in the AFFIRM study on ARR (i.e. 0.125, 0.170, and 0.250). RESULTS: Ninety-nine RRMS patients were included. The mean difference in the effect of NTZ-SC vs NTZ-IV on ARR was close to 0. The lower bound of the 95 % confidence interval (worst case scenario) was -0.119, corresponding to 25 % (p = 0.025) of the effect of NTZ-IV vs placebo on ARR. Sensitivity analyses confirmed the results of the primary non-inferiority analysis on the outcome CUAL. CONCLUSIONS: NTZ-SC resulted not inferior to NTZ-IV on ARR for all the non-inferiority margins. The non-inferiority analysis of the efficacy of NTZ-SC vs NTZ-IV on CUAL was demonstrated to be robust with respect to rescued patients.

High NEDA and No PIRA in Natalizumab-Treated Patients With Pediatric-Onset Multiple Sclerosis.

BACKGROUND AND OBJECTIVES: Although pediatric-onset multiple sclerosis (POMS) is characterized by a more rapid accumulation of CNS inflammation than adult-onset MS (AOMS), the therapeutic algorithms applied in POMS are usually based on AOMS therapeutic outcomes. To define a high-efficacy treatment (HET)-based strategy to treat POMS, we designed an observational retrospective study aimed at evaluating the efficacy and safety of natalizumab (NTZ) in naïve POMS and AOMS. METHODS: Starting from 160 patients, we applied a 2:1 (adult:pediatric) matching on propensity scores and obtained 32 patients with NTZ-treated POMS and 64 with AOMS, estimated from a multivariable logistic regression model. All patients were clinically and radiologically followed up every 6 months for a mean period of 46.0 ± 26.9 months. RESULTS: Following re-baseline at month 6, no difference (log-rank test: p = 0.924) in new and enlarging T2 white matter lesions, postcontrast T1 lesions, and relapse rate were observed between POMS and AOMS throughout the study. Progression independent of relapse activity (PIRA) was never observed in POMS, while 9 of 64 patients with AOMS (12.5%) had PIRA events during the follow-up (40.0 ± 25.9 months; log-rank p value 0.0156). JCV seroconversion rate during NTZ infusion did not differ between POMS and AOMS (log-rank test p = 0.3231). Finally, no serious adverse event was observed in both POMS and AOMS. DISCUSSION: The favorable outcomes observed on clinical, especially in PIRA, and radiologic parameters strongly support the use of NTZ as a first-choice HET in POMS.

Subcutaneous administration of natalizumab can lead to lower drug concentrations compared to intravenous administration.

BACKGROUND: Several studies reported lower drug concentrations with subcutaneous natalizumab compared to intravenous natalizumab. With the emergence of extended interval dosing, gaining more insight into lower concentrations after subcutaneous administration is essential. METHODS: We compared serum trough concentrations between subcutaneous and intravenous administration within a matched cohort (n = 50). RESULTS: Subcutaneous administration (n = 25) was associated with lower concentrations compared to intravenous administration (n = 25) (log-B=-0.28, p = 0.01). In an exploratory group of 11 patients receiving extended interval dosing of subcutaneous natalizumab, the median trough concentration was even lower. CONCLUSION: Subcutaneous natalizumab can lead to lower drug concentrations, potentially limiting extended interval dosing.

Switching from injectable to other Disease Modifying Therapies may improve sexual dysfunction in people with Multiple Sclerosis.

BACKGROUND: Multiple Sclerosis (MS) a central nervous system autoimmune disorder, mainly affecting young adults and more prevalent among women, can lead to sexual dysfunction (SD) among both males and females with MS. Female sexual dysfunction can be defined as dyspareunia, a lack of sexual desire, disorders in the arousal and orgasm phases, and sexual pain disorders. The purpose of this study is to investigate the changes in sexual function among females with MS whose treatment was switched from first-line injectable medications to other agents after a six-month duration. And assess the changes in all three domains of SD. METHODS: In this longitudinal study females diagnosed with MS, aged between 18 and 50 years old, and were candidates for switching their treatment from interferon beta-1a (intra-muscular and subcutaneous), and Glatiramer Acetate (GA), to Fingolimod, Dimethyl Fumarate (DMF), or Natalizumab (NTZ) due to patients' convenience and tolerability and adverse events were included. "Multiple Sclerosis Intimacy and Sexuality Questionnaire-19" was used to evaluate the SD changes before and six months after the new treatment initiation. Statistical analysis was conducted using SPSS V.24 software. Histograms and the Shapiro-Wilk test were used to assess the normality of the variables; due to the non-normal distribution of quantitative variables (except for age), the Wilcoxon signed-rank test was used to compare the scores, before and six months after the medication change. The level of significance was considered less than 0.05. RESULTS: Out of 107 female participants (average age: 35.09 ± 5.61), The mean of overall MSISQ-19 scores, before and six months after the medication change were not significant (p-value = 0.091). However, considering the subdomains, the medication changes only affected the tertiary subdomain of MSISQ-19 (p-value = 0.017). Still, the scores of other subdomains did not change significantly (p-value = 0.761 for primary SD and 0.479 for secondary SD). Also, there wasn't any significant difference between EDSS before and after the medication change (p-value = 0.461). CONCLUSIONS: To our knowledge, this was the first study, assessing the effect of MS medication change on the improvement of SD among patients. According to the results of the presented cross-sectional study, we found that during a six-month period, the tertiary subdomain of MSISQ-19 symptoms improved significantly, while the changes in other SD domains were not significant.

Age-corrected neurofilament light chain ratio decreases but does not predict relapse in highly active multiple sclerosis patients initiating natalizumab treatment.

BACKGROUND: Neurofilament light chain (NFL) is a biomarker for monitoring disease activity and treatment response in multiple sclerosis (MS). However, while most agree that NFL levels predict disease activity and worsening, the predictive value of NFL on future relapse risk remains uncertain. OBJECTIVE: The primary aim was to evaluate the predictive value of age-corrected serum NFL (sNFL) ratio on relapse risk in highly active relapsing-remitting MS patients (RRMS) treated with natalizumab. A secondary aim was to investigate the predictive value of sNFL ratios for MRI activity. METHODS: From January 1, 2006, to December 31, 2010, 355 patients initiated natalizumab treatment at the Danish Multiple Sclerosis Center. 305 patients were anti-natalizumab antibodies negative and had at least one blood sample available for sNFL analysis using single molecule array analysis at baseline, three, six, or 12 months. The patients were either treatment-naïve (n = 8), switching from interferon-ß or glatiramer acetate (n = 253), or switching from mitoxantrone (n = 44). An age-corrected ratio was calculated for sNFL. Time to first relapse was calculated from baseline and after re-baseline at 90 days. Data were collected from baseline until the two-year follow-up or end of treatment and included disease duration, expanded disability status scale, previous treatments, relapses 12 months prior to natalizumab initiation, smoking intensity, body mass index, and body weight. In addition, the patients underwent annual MRI of the brain. RESULTS: The sNFL ratio was increased in 173 of 287 samples (60.3 %) at baseline, in 119 of 246 samples (48.8 %) at month three, in 109 of 287 samples (38.0 %) at month six, and in 82 of 270 samples (30.4 %) at month 12. The sNFL ratio continuously declined over 12 months with significant decreases for every measuring timepoint: baseline vs. three months p = 3.0 × 10-6; three months vs. six months p = 3.2 × 10-5; six months vs. 12 months p = 0.002. Univariate Cox regression analysis showed that time to first relapse from 1) natalizumab initiation and from 2) re-baseline was associated with the number of relapses in the previous 12 months (hazard ratio 1.31 per relapse, 95 % CI = 1.2-1.5, p = 2.0 × 10-6; and 1.21 per relapse, 95 % CI = 1.1-1.4, p = 0.002, respectively). sNFL ratio at re-baseline was negatively associated with relapse risk (hazard ratio 0.82 per unit; 95 % CI = 0.7-1.0; p = 0.049). A multivariable Cox regression analysis of relapse risk from re-baseline showed that the number of relapses in the 12 months prior to natalizumab treatment (hazard ratio 1.29; 95 % CI = 1.1-1.5; p = 6.0 × 10-4) and smoking (hazard ratio 1.51 per 20 cigarettes per day; 95 % CI = 1.0-2.2; p = 0.030) were associated with increased risk of relapse; sNFL ratio was associated with a lower risk of relapse (hazard ratio = 0.736 per unit; 95 % CI = 0.6-0.9 p = 0.007). In univariate logistic regression analyses, the sNFL ratio at 12 months and values above the 75th and the 90th percentile predicted MRI activity in the following year (odds ratio [OR] = 2.0, 95 % CI = 1.2-3.6, p = 0.012; OR = 2.2, 95 % CI = 1.2-4.1, p = 0.014; and OR = 2.8, 95 % CI = 1.1-6.7, p = 0.026). CONCLUSION: In this highly active RRMS cohort, high sNFL ratios reflected previous relapse activity and decreased after initiation of treatment but were not associated with increased relapse risk in the following two years. Pre-treatment relapses and smoking on treatment were predictors of relapse risk after re-baselining at 90 days. MRI activity in year two was predicted by sNFL ratios at month 12.

Influence of personalized extended interval dosing on the natalizumab wearing-off effect - a sub-study of the NEXT-MS trial.

BACKGROUND AND OBJECTIVES: Wearing-off symptoms during natalizumab treatment in multiple sclerosis are characterized by an increase of MS-related symptoms prior to natalizumab administration. The influence of extended interval dosing (EID) on wearing-off symptoms are important to consider, as this might cause hesitancy in initiating or continuing EID. METHODS: Participants of the NEXT-MS trial, in which treatment intervals are adjusted based on drug concentrations, were divided into two groups: an extended group containing participants with at least one week of additional interval extension, and a group with a fixed interval during the trial (range 4-7 weeks). Changes in the occurrence, frequency, onset, and severity of wearing-off symptoms were evaluated. RESULTS: 255 participants were included (extended group n = 171, fixed group n = 84). The odds on occurrence of wearing-off symptoms in the extended group did not increase after extending the treatment interval. Additional analyses for frequency, onset, and severity of wearing-off symptoms showed no changes over time. Mean decrease in natalizumab drug concentration did not influence the frequency of wearing-off symptoms. DISCUSSION: Wearing-off symptoms were not reinforced by further extending the natalizumab interval. Wearing-off symptoms might increase in a minority of patients after EID, although our data support the view that wearing-off symptoms appear to be unrelated to the decrease in natalizumab trough drug concentrations.

NEDA-3 achievement in early highly active relapsing remitting multiple sclerosis patients treated with Ocrelizumab or Natalizumab.

BACKGROUND: in the early stages of Multiple Sclerosis (MS), initiating high-efficacy disease-modifying therapy (HE DMTs) may represent an optimal strategy for delaying neurological damage and long-term disease progression, especially in highly active MS patients (HAMS). Natalizumab (NAT) and Ocrelizumab (OCR) are recognized as HE DMTs with significant anti-inflammatory effects. This study investigates NEDA-3 achievement in treatment-naïve HAMS patients receiving NAT or OCR over three years. METHODS: we retrospectively enrolled treatment-naïve HAMS patients undergoing NAT or OCR, collecting demographic, clinical, and instrumental data before and after treatment initiation to compare with propensity score analysis disease activity, time to disability worsening, and NEDA-3 achievement. RESULTS: we recruited 281 HAMS patients with a mean age of 32.7 years (SD 10.33), treated with NAT (157) or OCR (124). After three years, the Kaplan-Meier probability of achieving NEDA-3 was 66.0 % (95 % CI: 57.3 % - 76.0 %) with OCR and 68.2 % (95 % CI: 59.9 % - 77.7 %) with NAT without significant differences between the two groups (p = 0.27) DISCUSSION AND CONCLUSION: starting HE DMT with monoclonal antibodies for HAMS could achieve NEDA-3 in a high percentage of patients without differences between NAT or OCR.

Intact natalizumab pharmacokinetics is impacted by endogenous IgG4 concentration.

BACKGROUND: Natalizumab (NAT) pharmacokinetics and pharmacodynamics are complicated by arm exchange with endogenous IgG4, resulting in a mixture of a more potent intact, bivalent form and a less potent, functionally monovalent form. Total NAT and endogenous IgG4 concentrations vary considerably across patients. This study assessed the concentration of intact NAT, and how it relates to total NAT and endogenous IgG4 levels in blood and saliva. METHODS: Paired serum and saliva samples from a small cohort of relapsing-remitting multiple sclerosis patients were measured for levels of intact NAT, total NAT, IgG and IgG4. RESULTS: Intact NAT concentration was dependent on both total NAT and endogenous IgG4 levels. Low endogenous IgG4 led to a higher ratio of intact NAT to total NAT, while the opposite was observed in subjects with high endogenous IgG4. Serum and saliva measurements show good concordance. CONCLUSIONS: Intact NAT concentration is influenced by both NAT pharmacokinetics and endogenous IgG4 levels. Patients with low IgG4 levels can have high concentrations of intact NAT even with lower levels of total NAT, which may explain cases of NAT-associated progressive multifocal leukoencephalopathy (PML) in such patients. Monitoring both forms of NAT could better guide dosing, maximizing drug efficacy and safety.

Long-term neuroprotective effects of natalizumab and fingolimod in multiple sclerosis: Evidence from real-world clinical data.

BACKGROUND: The long-term effect of high efficacy disease modifying therapy (DMT) on neurodegeneration in people with multiple sclerosis (pwMS) is largely unknown. The aim of this study was to evaluate the long-term effect of natalizumab (NTZ) or fingolimod (FTY) therapy on the evolution of brain atrophy compared to moderate efficacy DMT in a real-world clinical setting. METHODS: A total of 438 pwMS with 2,439 MRI exams during treatment were analyzed: 252 pwMS treated with moderate efficacy DMT, 130 with NTZ and 56 with FTY. Evolution of brain atrophy was analyzed over an average follow-up of 6.6 years after treatment initiation. Brain segmentation was performed on clinical 3D-FLAIRs using SynthSeg and regional brain volume changes over time were compared between the treatment groups. RESULTS: Total brain, white matter and deep gray matter atrophy rates did not differ between moderate efficacy DMTs, NTZ and FTY. Annualized ventricle growth rates were lower in pwMS treated with NTZ (1.1 %/year) compared with moderate efficacy DMT (2.4 %/year, p < 0.001) and similar to FTY (2.0 %/year, p = 0.051). Cortical atrophy rates were lower in NTZ (-0.08 %/year) compared with moderate efficacy DMT (-0.16 %/year, p = 0.048). CONCLUSION: In a real-world clinical setting, pwMS treated with NTZ had slower ventricular expansion and cortical atrophy compared to those treated with moderate efficacy DMT.

Vaccine Safety and Immunogenicity in Patients With Multiple Sclerosis Treated With Natalizumab.

Importance: Vaccination in patients with highly active multiple sclerosis (MS) requiring prompt treatment initiation may result in impaired vaccine responses and/or treatment delay. Objective: To assess the immunogenicity and safety of inactivated vaccines administered during natalizumab treatment. Design, Setting, and Participants: This self-controlled, prospective cohort study followed adult patients with MS from 1 study center in Spain from September 2016 to February 2022. Eligible participants included adults with MS who completed immunization for hepatitis B virus (HBV), hepatitis A virus (HAV), and COVID-19 during natalizumab therapy. Data analysis was conducted from November 2022 to February 2023. Exposures: Patients were categorized according to their time receiving natalizumab treatment at the time of vaccine administration as short-term (≤1 year) or long-term (>1 year). Main Outcomes and Measures: Demographic, clinical, and radiological characteristics were collected during the year before vaccination (prevaccination period) and the year after vaccination (postvaccination period). Seroprotection rates and postvaccination immunoglobulin G titers were determined for each vaccine within both periods. Additionally, differences in annualized relapse rate (ARR), new T2 lesions (NT2L), Expanded Disability Status Scale (EDSS) scores, and John Cunningham virus (JCV) serostatus between the 2 periods were assessed. Results: Sixty patients with MS (mean [SD] age, 43.2 [9.4] years; 44 female [73.3%]; 16 male [26.7%]; mean [SD] disease duration, 17.0 [8.7] years) completed HBV, HAV, and mRNA COVID-19 immunization during natalizumab treatment, with 12 patients in the short-term group and 48 patients in the long-term group. The global seroprotection rate was 93% (95% CI, 86%-98%), with individual vaccine rates of 92% for HAV (95% CI, 73%-99%), 93% for HBV (95% CI, 76%-99%), and 100% for the COVID-19 messenger RNA vaccine (95% CI, 84%-100%). Between the prevaccination and postvaccination periods there was a significant reduction in the mean (SD) ARR (0.28 [0.66] vs 0.01 [0.12]; P = .004) and median (IQR) NT2L (5.00 [2.00-10.00] vs 0.81 [0.00-0.50]; P = .01). No changes in disability accumulation were detected (median [IQR] EDSS score 3.5 [2.0-6.0] vs 3.5 [2.0-6.0]; P = .62). No differences in safety and immunogenicity were observed for all vaccines concerning the duration of natalizumab treatment. Conclusions and Relevance: The findings of this cohort study suggest that immunization with inactivated vaccines during natalizumab therapy was both safe and immunogenic, regardless of the treatment duration. Natalizumab may be a valuable option for proper immunization, averting treatment delays in patients with highly active MS; however, this strategy needs to be formally evaluated.

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.

Non-inferiority analysis of subcutaneous versus intravenous 300 mg monthly natalizumab administration: A post hoc analysis of the REFINE study.

To quantify the probability that monthly intravenous (IV) and subcutaneous (SC) natalizumab (NTZ) had similar efficacy in relapsing-remitting multiple sclerosis (RRMS), non-inferiority of efficacy of NTZ-SC versus NTZ-IV on combined MRI unique active lesions number (CUAL) was explored re-analysing the REFINE data set. Non-inferiority margins were selected equal to 25%/33%/50% fractions of the effect size of NTZ-IV versus placebo observed in the AFFIRM study. Ninety-nine RRMS were included. NTZ-SC resulted not inferior to NTZ-IV on CUAL for all margins at 2.5% significance level, and, in worst-case scenario, its effect over NTZ-IV did not exceed 3.5% (or 2.8%) of the effect of NTZ-IV versus placebo.

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 â€‹± â€‹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.

Influence of physicians' risk perception on switching treatments between high- efficacy and non-high-efficacy disease­modifying therapies in multiple sclerosis.

BACKGROUND: The decision of initiating treatment for multiple sclerosis (MS) with a high-efficacy DMT (HE DMT) or non-high-efficacy DMT (non-HE DMT) is influenced by several factors, including risk perception of patients and physicians. OBJECTIVE: Investigate the influence of physicians' risk perception on decision-making when switching treatments for MS and the reasons for switching. METHODS: Data were drawn from the Adelphi Real-World MS Disease-Specific Program (a retrospective survey) and analysis included people with RMS identified between 2017- 2021. RESULTS: Of 4129 patients with reasons for switch available, 3538 switched from non-HE DMT and 591 from HE DMT. Overall, 4.7% of patients were switched treatment by their physicians due to the risk of malignancies and infections including PML risk. The proportion of switches that were made due to the risk of PML were 23.9% in the HE DMT and 0.5% in the non-HE DMT groups. The top reasons for switching were relapse frequency (non-HE DMT vs HE-DMT: 26.8% vs 15.2%), lack of efficacy (20.9 vs 11.7) and increased number of MRI lesions (20.3% vs 12.4%). CONCLUSIONS: Physicians' risk perception of malignancies and infection excluding PML was not a leading factor when switching treatment. The risk of PML was a key factor, especially for switching patients from HE DMTs. In both groups, lack of efficacy was the key contributing factor for switching. Initiating the treatment with HE DMTs may potentially reduce the number of switches due to sub-optimal efficacy. These findings might help physicians to engage more in discussions with patients about the benefit/risk profile of DMTs.

Real-World Data Regarding Long-Term Administration of Natalizumab Derived from a Neurology Department along with Literature Review.

BACKGROUND: Natalizumab is a humanized monoclonal antibody with high efficacy and an acceptable safety profile used in the treatment of patients with multiple sclerosis (MS). OBJECTIVE: Our aim was to report data regarding long-term administration of Natalizumab in patients with Relapsing-Remitting Multiple Sclerosis (RRMS) from our clinic. METHODS: A retrospective observational study was performed including RRMS patients who underwent treatment with ≥ 24 Natalizumab infusions. We analyzed EDSS values, the relapse rate and the rate and type of adverse events related to Natalizumab administration. RESULTS: 51 subjects were included with a predominance of women (62.74%), with an average age of 40.43±1.49 years, a mean disease duration of 9.86±0.7 years and mean number of Natalizumab infusions of 45.58±2.74. An increased number of patients (80.39%) were relapse-free and a mild reduction of the mean EDSS value following Natalizumab initiation in patients who had not been treated with other disease modifying therapies anteriorly was observed. Among the encountered adverse events such as increased liver transaminases (13.72%), local infections (7.84%) and dysmenorrhea in one patient were registered in this study. The rate of severe adverse events was 3.92 and no cases of Progressive Multifocal Leukoencephalopathy (PML) were registered. CONCLUSION: Natalizumab proves to be effective, has an adequate safety profile and can be administered with good tolerability for a rather extended period of time, provided that the patients are closely monitored.

Secondary Immunodeficiency and Risk of Infection Following Immune Therapies in Neurology.

Secondary immunodeficiencies (SIDs) are acquired conditions that may occur as sequelae of immune therapy. In recent years a number of disease-modifying therapies (DMTs) has been approved for multiple sclerosis and related disorders such as neuromyelitis optica spectrum disorders, some of which are frequently also used in- or off-label to treat conditions such as chronic inflammatory demyelinating polyneuropathy (CIDP), myasthenia gravis, myositis, and encephalitis. In this review, we focus on currently available immune therapeutics in neurology to explore their specific modes of action that might contribute to SID, with particular emphasis on their potential to induce secondary antibody deficiency. Considering evidence from clinical trials as well as long-term observational studies related to the patients' immune status and risks of severe infections, we delineate long-term anti-CD20 therapy, with the greatest data availability for rituximab, as a major risk factor for the development of SID, particularly through secondary antibody deficiency. Alemtuzumab and cladribine have relevant effects on circulating B-cell counts; however, evidence for SID mediated by antibody deficiency appears limited and urgently warrants further systematic evaluation. To date, there has been no evidence suggesting that treatment with fingolimod, dimethyl fumarate, or natalizumab leads to antibody deficiency. Risk factors predisposing to development of SID include duration of therapy, increasing age, and pre-existing low immunoglobulin (Ig) levels. Prevention strategies of SID comprise awareness of risk factors, individualized treatment protocols, and vaccination concepts. Immune supplementation employing Ig replacement therapy might reduce morbidity and mortality associated with SIDs in neurological conditions. In light of the broad range of existing and emerging therapies, the potential for SID warrants urgent consideration among neurologists and other healthcare professionals.