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.

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.

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.

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.

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.