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.

Switching from natalizumab to an anti-CD20 monoclonal antibody in relapsing remitting multiple sclerosis: A systematic review.

BACKGROUND: Use of natalizumab (NTZ) is precluded in many Multiple Sclerosis (MS) patients by the risk of progressive multifocal leukoencephalopathy (PML). Regardless, some patients may commence natalizumab for short term disease control in spite of being seropositive, and others may seroconvert whilst on treatment. In these circumstances, discontinuation of NTZ should not occur until a clear exit strategy is established to prevent post-NTZ disease reactivation, which often exceeds the severity of disease activity prior to NTZ treatment. The objective of this systematic review was to summarise the available evidence for CD20-monoclonal antibodies (CD20mAb) as a suitable NTZ exit strategy, and to identify whether a superior switch protocol can be established. METHODS: In accordance with PRISMA guidelines, a total of 2393 references were extracted from a search of three online databases (PubMed, Scopus, MEDLINE). Following the application of inclusion/exclusion criteria, a total of 5 studies representing 331 patients were included. RESULTS: The overall incidence of clinical relapse during washout periods ranging from 4.4-10.7 weeks was 0 %. The incidence of clinical relapse during two-year follow-up ranged from 1.8 % to 10 % for switches to all types of CD20 monoclonal antibody. The weighted mean for clinical relapse at 12 months was 8.8 %. Three studies reported an annualised relapse rate (ARR) ranging from 0.02-0.12 with a weighted mean ARR of 0.07. The overall incidence of PML during washout was 0 % and the overall incidence of PML within 6 months follow-up was 0.6 %. CONCLUSIONS: This systematic review provides the first attempt at identifying a superior switch protocol in patients at risk of PML transitioning from NTZ to a CD20mAb. Our results indicate that CD20mAb's are a suitable transitional option for patients who discontinue NTZ, with our cohort demonstrating very low rates of carryover PML and low rates of clinical relapse. The most appropriate washout period is unclear due to confounding factors but is likely between 4 and 12 weeks.

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.

Efectividad clínica y radiológica del intervalo extendido de dosis con natalizumab en pacientes con esclerosis múltiple recurrente / Clinical and radiological effectiveness of natalizumab extended dosage interval in patients with relapsing multiple sclerosis

Introducción: El natalizumab (NTZ) es un tratamiento de alta eficacia aprobado para la esclerosis múltiple de alta actividad. El principal riesgo del tratamiento con NTZ es la posibilidad de desarrollar una leucoencefalopatía multifocal progresiva, que está en relación con la positividad al virus JC y el número de infusiones del NTZ. Este riesgo disminuye con el intervalo extendido de dosis (IED), lo que supone 9 infusiones/año o menos. Sin embargo, es materia de controversia si el IED mantiene la efectividad sobre la reducción de las recurrencias y la presencia de nuevas lesiones en la resonancia magnética (RM). Pacientes y métodos: Se ha realizado un estudio observacional prospectivo desde el 1 de abril de 2019 hasta el 30 de junio de 2021, siguiendo a los pacientes en tratamiento con NTZ que se pasaron al IED. Los pacientes deberían tener al menos una RM a los seis meses del inicio del IED. Se registró la presencia de brotes o de actividad en la RM (nuevas lesiones en T2) durante el IED. Resultados: Se incluyó a 23 pacientes con una media de edad de 43,5 ± 9,4 años. La mediana de infusiones de NTZ fue de 68 (mínimo, 25; máximo, 127). La mediana del intervalo entre el inicio del IED y la última RM fue de 14 meses (mínimo, 6; máximo, 25), y de 23 meses respecto a la última visita de seguimiento médico (mínimo, 7; máximo, 28). Dos pacientes (8,7%) presentaron brotes y otros dos pacientes (8,7%) presentaron actividad en la RM. Conclusiones: El IED de NTZ mantiene una alta efectividad clínica y de actividad en la RM.(AU)

Introduction: Natalizumab (NTZ) is a very effective treatment approved for highly active multiple sclerosis. The main risk of treatment with NTZ is the possibility of developing progressive multifocal leukoencephalopathy, which is related to JC virus positivity and the number of NTZ infusions. This risk decreases with the extended dosage interval (EDI), which involves 9 or fewer infusions/year. However, it is a matter of controversy as to whether EDI remains effective in reducing recurrences and the presence of new lesions in magnetic resonance imaging (MRI). Patients and methods: A prospective observational study was conducted from 1 April 2019 to 30 June 2021, following up patients on NTZ treatment who switched to EDI. Patients should have at least one MRI six months after the start of EDI. The presence of attacks or MRI activity (new lesions in T2) during the EDI was recorded. Results: Twenty-three patients with a mean age of 43.5 ± 9.4 years were included. The median number of NTZ infusions was 68 (minimum, 25; maximum, 127). The median interval between the start of the EDI and the last MRI was 14 months (minimum, 6; maximum, 25), and 23 months from the last medical follow-up visit (minimum, 7; maximum, 28). Two patients (8.7%) presented with attacks and two others (8.7%) showed MRI activity. Conclusions: EDI with NTZ maintains high clinical and activity effectiveness in MRI.(AU)

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.

Home infusions of natalizumab for people with multiple sclerosis: a pilot randomised crossover trial.

OBJECTIVE: The delivery of healthcare at home has expanded to intravenous infusions of monoclonal antibodies. A recently developed model of care for home infusions of natalizumab for people with relapsing-remitting multiple sclerosis was evaluated. This pilot study of home infusions of natalizumab and usual care (attendance in a hospital out-patients' clinic) compared safety, feasibility, patient satisfaction, effectiveness and costs. METHODS: In this randomised AB/BA crossover trial, 37 adults were randomised to usual care (n = 19) or home infusions (n = 18). After three infusions, patients crossed over to the alternate treatment for another three infusions. Patient safety outcomes and adherence, satisfaction, quality of life, disability and costs were compared. RESULTS: No adverse events were recorded from 207 infusions from 35 patients across both home and clinic infusions. There was no difference in adherence (p = 0.71) and infection rates (p = 0.84) between home and clinic settings. Satisfaction with "convenience" of home infusions was significantly greater (p = 0.008) but there were no differences in quality of life measures. Excluding pharmacy, costs were A$74 lower per infusion at home, including A$16 of patients" out-of-pocket costs. INTERPRETATION: There were no differences in safety and effectiveness between clinic and home infusions of natalizumab. The home infusions were shown to be feasible, more convenient and less expensive than usual care. Larger scale studies are required to verify these preliminary findings, particularly around safety and management of hypersensitivity adverse events in the home setting and for equivalence of clinical outcomes.

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

The extended interval dosing (EID) of natalizumab has been suggested to be associated with a reduced risk of progressive multifocal leukoencephalopathy (PML) and short-term preservation of efficacy but its long-term effectiveness remain unknown. We aimed to determine the long-term effectiveness and safety of natalizumab in an EID setting in a cohort of patients with multiple sclerosis (MS) treated for more than 7 years. We conducted an observational retrospective cohort study, including 39 (34 female, 5 male) patients with clinically definite relapsing-MS, initially treated with standard interval dosing (SID) of natalizumab (mean time 54 months [SD29]) who were then switched to EID, every 8 weeks (mean time 76 months [SD13]). The main outcome measures included the following: i) annualized relapse rate (ARR), ii) radiological activity, iii) disability progression, and iv) NEDA-3 no evidence of disease activity index. EID preserved ARR, radiological activity, and prevented disability worsening during follow-up. The proportion of patients maintaining their NEDA-3 status after 24, 48, and 72 months of natalizumab administration in EID was 94%, 73%, and 70%, respectively. Stratified analysis according to history of drug therapy showed that the EID of natalizumab was slightly more effective in naïve patients than in those previously treated with other immunosuppressive drugs. No cases of PML or other severe adverse reactions were reported. In conclusion, long-term therapy with natalizumab in an EID setting following an SID regimen maintained its disease-modifying activity, and was safe and well tolerated for over 7 years. These encouraging observational results need to be confirmed in controlled clinical trials.

Serum Neurofilament Levels and PML Risk in Patients With Multiple Sclerosis Treated With Natalizumab.

OBJECTIVES: The study aimed to assess the potential for serum neurofilament light chain (NFL) levels to predict the risk of progressive multifocal leukoencephalopathy (PML) in natalizumab (NTZ)-treated patients with multiple sclerosis (MS) and to discriminate PML from MS relapses. METHODS: NFL levels were measured with single molecule array (Simoa) in 4 cohorts: (1) a prospective cohort of patients with MS who developed PML under NTZ therapy (pre-PML) and non-PML NTZ-treated patients (NTZ-ctr); (2) a cohort of patients whose blood was collected during PML; (3) an independent cohort of non-PML NTZ-treated patients with serum NFL determinations at 2 years (replication cohort); and (4) a cohort of patients whose blood was collected during exacerbations. RESULTS: Serum NFL levels were significantly increased after 2 years of NTZ treatment in pre-PML patients compared with NTZ-ctr. The prognostic performance of serum NFL levels to predict PML development at 2 years was similar in the NTZ-ctr group and replication cohort. Serum NFL levels also distinguished PML from MS relapses and were 8-fold higher during PML compared with relapses. CONCLUSIONS: These results support the use of serum NFL levels in clinical practice to identify patients with relapsing-remitting MS at higher PML risk and to differentiate PML from clinical relapses in NTZ-treated patients. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that serum NFL levels can identify NTZ-treated patients with MS who will develop PML with a sensitivity of 67% and specificity of 80%.

Exit Strategies in Natalizumab-Treated RRMS at High Risk of Progressive Multifocal Leukoencephalopathy: a Multicentre Comparison Study.

The main aim of the study is to evaluate the efficacy and safety profile of ocrelizumab (OCR), rituximab (RTX), and cladribine (CLA), employed as natalizumab (NTZ) exit strategies in relapsing-remitting multiple sclerosis (RRMS) patients at high-risk for progressive multifocal leukoencephalopathy (PML). This is a multicentre, retrospective, real-world study on consecutive RRMS patients from eleven tertiary Italian MS centres, who switched from NTZ to OCR, RTX, and CLA from January 1st, 2019, to December 31st, 2019. The primary study outcomes were the annualized relapse rate (ARR) and magnetic resonance imaging (MRI) outcome. Treatment effects were estimated by the inverse probability treatment weighting (IPTW), based on propensity-score (PS) approach. Additional endpoint included confirmed disability progression (CDP) as measured by Expanded Disability Status Scale and adverse events (AEs). Patients satisfying predefined inclusion and exclusion criteria were 120; 64 switched to OCR, 36 to RTX, and 20 to CLA. Patients from the 3 groups did not show differences for baseline characteristics, also after post hoc analysis. The IPTW PS-adjusted models revealed that patients on OCR had a lower risk for ARR than patients on CLA (ExpBOCR 0.485, CI 95% 0.264-0.893, p = 0.020). This result was confirmed also for 12-month MRI activity (ExpBOCR 0.248 CI 95% 0.065-0.948, p = 0.042). No differences were found in other pairwise comparisons (OCR vs RTX and RTX vs CLA) for the investigated outcomes. AEs were similar among the 3 groups. Anti-CD20 drugs were revealed to be effective and safe options as NTZ exit strategies. All investigated DMTs showed a good safety profile.

Improving risk-stratification of natalizumab-associated PML.

Based on publicly available data, we reevaluated current algorithms for stratifying the risk of progressive multifocal leukoencephalopathy (PML) in natalizumab-treated patients with multiple sclerosis, and found that there are a number of issues. First and foremost, our analysis highlights the necessity of separate PML incidence assessments for the U.S. versus Europe, and indicates that the risk in John Cunningham virus (JCV) antibody-negative patients may be higher than previously communicated. Additionally, we advocate introducing a low-risk JCV index threshold of 0.45 for individuals with prior exposure to an immunosuppressant, and setting the low-risk threshold at 0.6 instead of 0.9 for those without such pretherapies. On the other hand, the risk of PML on natalizumab, in general, appears to not only plateau but to actually decrease after about 5 years of continuous dosing.

Fast and safe: Optimising multiple sclerosis infusions during COVID-19 pandemic.

BACKGROUND: The COVID-19 pandemic challenges multiple sclerosis services to be innovative in delivering infusible therapies. To reduce time in clinical settings, and potential staff or space losses, we implemented rapid infusion protocols for selected patients. OBJECTIVE: To analyse the rate of infusion related reactions and patient experience of rapid infusions of natalizumab and ocrelizumab. To document time reduction patients spent in clinical settings during the COVID-19 pandemic. METHODS: Patients with prior exposure to at least three natalizumab or two 300mg ocrelizumab infusions were approved for rapid protocols. A retrospective audit and survey were completed. RESULTS: We analysed 269 rapid natalizumab infusions and 100 rapid ocrelizumab infusions. Infusion related reactions during the natalizumab or ocrelizumab infusions occurred in two patients (1.52%) and eight patients (8%), respectively. All infusion related reactions were mild to moderate and did not require infusion discontinuation. No infusion reactions occurred during the post-infusion observation. Patient experience was positive. CONCLUSION: Frequency or severity of infusion related reactions in rapid infusions were no different compared to published data. In the setting of COVID-19, pandemic rapid infusion protocols could potentially save hospital resources and limit patient exposure to a high-risk clinical setting while still maintaining ongoing treatment of multiple sclerosis.

Modeling the Efficacy of Natalizumab in Multiple Sclerosis Patients Who Switch From Every-4-Week Dosing to Extended-Interval Dosing.

Natalizumab is approved for multiple sclerosis treatment at a dose of 300 mg every 4 weeks. Extended-interval dosing of natalizumab has been proposed as a strategy to mitigate the risk of progressive multifocal leukoencephalopathy, but the efficacy of extended-interval dosing is not established. Previous models suggesting lower efficacy when initiating natalizumab treatment with extended-interval dosing rather than every-4-week dosing are inconsistent with reports from clinical observations and real-world studies conducted in patient populations switching to extended-interval dosing after a period of receiving natalizumab every 4 weeks. Here, the efficacy of natalizumab extended-interval dosing was modeled specifically in patients switching from every-4-week dosing to extended-interval dosing. Published population pharmacokinetic/pharmacodynamic models were used to simulate the distribution of alpha-4 integrin saturations for different body weight categories and dosing intervals (every 5, 6, 7, 8, 10, or 12 weeks). Generalized estimating equations relating alpha-4 integrin saturation to probability of multiple sclerosis lesion or relapse were derived from RESTORE trial data, which included patients (n = 175) who discontinued natalizumab after being treated every 4 weeks for ≥1 year and had no relapses in the year before discontinuation. The model-based simulations described indicate that every-5-week or every-6-week dosing is likely to maintain the efficacy of natalizumab, particularly at body weights <80 kg, in patients who switch after a period of stability on every-4-week dosing. The efficacy of natalizumab decreases as dosing intervals and body weight increase. Partial model validation was achieved in that observed outcomes in an independent clinical study were similar to those predicted by the models.

Disease activity in pregnancy and postpartum in women with MS who suspended rituximab and natalizumab.

OBJECTIVE: To evaluate risks of disease reactivity during pregnancy and postpartum following rituximab (RTX) and natalizumab (NTZ) suspension in women with MS. METHODS: An observational cohort study of all women with MS disease onset before childbirth between 2006 and 2017. Women were identified through the Swedish MS Registry, a nationwide clinical register, with substratification into 3 groups: women who suspended RTX and NTZ within 6 months before conception and women who were not treated with any disease-modifying treatment (DMT) within 1 year of conception. The primary outcome was the annualized relapse rate (ARR) during pregnancy and 1 year postpartum. RESULTS: We identified 2,386 women with MS onset before a live birth; of these, 76 women suspended RTX and 53 suspended NTZ, and 457 were untreated within 1 year before conception. In all women, regardless of the treatment type, the ARR declined from 0.05-0.04 prepregnancy to 0.03-0.02 during pregnancy, returning to prepregnancy rates at 3-6 months (0.05) postpartum. In the suspended cohort, 76% (98/129) of women resumed a DMT after delivery. The relapse rate 1 year postpartum was significantly higher in the suspended NTZ women compared with the suspended RTX women (adjusted rate ratio [aRR] 7.65, 95% CI 2.47-23.6) and was lower in the suspended RTX women compared with the untreated women (aRR 0.21, 95% CI 0.08-0.61). CONCLUSION: Disease reactivity during the postpartum period was lower among women with MS who suspended RTX before pregnancy, relative to those who suspended NTZ and untreated women. These findings suggest that RTX may exert long-acting effects on MS disease activity that encompass pregnancy and postpartum periods. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that in patients with MS who were on treatment before pregnancy, RTX reduces clinical disease activity compared with NTZ in the postpartum period.

Clinical effectiveness of different natalizumab interval dosing schedules in a large Italian population of patients with multiple sclerosis.

INTRODUCTION: Natalizumab (NTZ) is one of the most effective treatment options for multiple sclerosis (MS) treatment. Our study aimed to evaluate the effectiveness of NTZ when administered according to the extended dosing strategy compared with standard 4-weekly administration in a large Italian MS population. MATERIALS AND METHODS: This retrospective multicentre study included patients with relapsing-remitting MS (RR-MS) who received NTZ administrations between the 1 June 2012 and the 15 May 2018 and were followed by the 'Italian MS Register'. All patients with MS were stratified into two groups based on NTZ administration schedule: standard interval dosing (SID) patients who received infusions on average from 28 to 32 days (median 30) and extended interval dosing (EID) including patients who have been infused with interval between 33 and 49 days (median 43). Clinical data were assessed at baseline (before starting NTZ), after 12 (T1) and 24 months (T2) of treatment. RESULTS: Out of 5231 patients with RR-MS screened, 2092 (mean age 43.2±12.0, 60.6% women) were enrolled. A total of 1254 (59.9%) received NTZ according to SID, and 838 (40.1%) according to EID. At 12 and 24 months, no differences in terms of annualised relapse rate and disability status were found between the two groups. Progression index and confirmed disability worsening were similar between the two groups. DISCUSSION: The use of NTZ with an extended interval schedule showed similar effectiveness compared with SID. Unchanged clinical efficacy of EID schedule may raise the question of a possible advantage in terms of tolerability and safety.

Delay from treatment start to full effect of immunotherapies for multiple sclerosis.

In multiple sclerosis, treatment start or switch is prompted by evidence of disease activity. Whilst immunomodulatory therapies reduce disease activity, the time required to attain maximal effect is unclear. In this study we aimed to develop a method that allows identification of the time to manifest fully and clinically the effect of multiple sclerosis treatments ('therapeutic lag') on clinical disease activity represented by relapses and progression-of-disability events. Data from two multiple sclerosis registries, MSBase (multinational) and OFSEP (French), were used. Patients diagnosed with multiple sclerosis, minimum 1-year exposure to treatment, minimum 3-year pretreatment follow-up and yearly review were included in the analysis. For analysis of disability progression, all events in the subsequent 5-year period were included. Density curves, representing incidence of relapses and 6-month confirmed progression events, were separately constructed for each sufficiently represented therapy. Monte Carlo simulations were performed to identify the first local minimum of the first derivative after treatment start; this point represented the point of stabilization of treatment effect, after the maximum treatment effect was observed. The method was developed in a discovery cohort (MSBase), and externally validated in a separate, non-overlapping cohort (OFSEP). A merged MSBase-OFSEP cohort was used for all subsequent analyses. Annualized relapse rates were compared in the time before treatment start and after the stabilization of treatment effect following commencement of each therapy. We identified 11 180 eligible treatment epochs for analysis of relapses and 4088 treatment epochs for disability progression. External validation was performed in four therapies, with no significant difference in the bootstrapped mean differences in therapeutic lag duration between registries. The duration of therapeutic lag for relapses was calculated for 10 therapies and ranged between 12 and 30 weeks. The duration of therapeutic lag for disability progression was calculated for seven therapies and ranged between 30 and 70 weeks. Significant differences in the pre- versus post-treatment annualized relapse rate were present for all therapies apart from intramuscular interferon beta-1a. In conclusion we have developed, and externally validated, a method to objectively quantify the duration of therapeutic lag on relapses and disability progression in different therapies in patients more than 3 years from multiple sclerosis onset. Objectively defined periods of expected therapeutic lag allows insights into the evaluation of treatment response in randomized clinical trials and may guide clinical decision-making in patients who experience early on-treatment disease activity. This method will subsequently be applied in studies that evaluate the effect of patient and disease characteristics on therapeutic lag.

Rituximab versus natalizumab, fingolimod, and dimethyl fumarate in multiple sclerosis treatment.

INTRODUCTION: Limited comparative effectiveness data for rituximab (RTX) versus natalizumab (NTZ), fingolimod (FTY), and dimethyl fumarate (DMF) for the treatment of multiple sclerosis (MS) exist. METHODS: Clinician-reported data on patients prescribed RTX, NTZ, FTY, or DMF for the treatment of MS at the Rocky Mountain MS Center at the University of Colorado were retrospectively collected. Outcomes included a composite effectiveness measure consisting of clinical relapse, contrast-enhancing lesions, and/or new T2 lesions, individual effectiveness outcomes, and discontinuation. Logistic regression was used on patients matched by propensity scores and using average treatment effect on treated doubly robust weighting estimator. RESULTS: A total of 182, 451, 271, and 342 patients initiated RTX, NTZ, FTY, and DMF and were followed for 2 years. Before and after adjustment, the odds of experiencing disease activity was significantly higher for FTY [adjusted OR (aOR) = 3.17 (95% CI: 1.81-5.55), P < 0.001].and DMF [aOR = 2.68 (95% CI:1.67-4.29), P < 0.001], and similar for NTZ [aOR = 1.36 (95% CI:0.83-2.23), P = 0.216] versus RTX. When examining months 6-24, NTZ demonstrated higher odds of disease activity compared to RTX [aOR = 2.21 (95% CI: 1.20-4.06), P = 0.007]. Similar odds of discontinuation were seen between NTZ and RTX [aOR = 1.39 (95% CI: 0.88-2.20), P = 0.157]; however, FTY [aOR = 2.02 (95% CI: 1.24-3.30), P = 0.005] and DMF [aOR = 3.27 (95% CI: 2.15-4.97), P < 0.001] had greater odds of discontinuation than RTX. INTERPRETATION: RTX demonstrated superior effectiveness and discontinuation outcomes compared to FTY and DMF. Although RTX demonstrated similar effectiveness and discontinuation compared to NTZ, RTX had superior effectiveness during months 6-24 and fewer discontinuations when excluding discontinuations due to insurance issues. Results suggest superiority of RTX in reducing disease activity and maintaining long-term treatment in a real-world MS cohort.