BACKGROUND AND OBJECTIVES:B-cell repopulation patterns in ocrelizumab treated patients with multiple sclerosis are highly variable between individuals, but the course of B-cell reoccurrence after subsequent doses within an individual is not yet determined. Our aim was to determine the intraindividual variability of CD19+ B-cell repopulation after each ocrelizumab dose when using CD19+ B-cell guided interval dosing. METHODS:This was a prospective cohort study, as part of the ongoing BLOOMS trial, investigating participants randomised for B-cell guided interval dosing of ocrelizumab with ≥ 2 dosing intervals. Coefficients of variation were calculated for time from last ocrelizumab dose to first CD19+ B-cell measurement ≥ 0.01 × 109 cells/L. RESULTS:Seventy-five participants with a total of 209 B-cell guided intervals were included. Time from last dose to first appearance of CD19+ B-cell count ≥ 0.01 × 109 cells/L showed wide variability between individuals (20.6-72.1 weeks), but the median variation was 5.6% (IQR: 3.1-8.4) within an individual. This translated to a variation of 2 weeks per dosing interval on average. DISCUSSION:Time to CD19+ B-cell repopulation after each ocrelizumab dose is individually stable. This finding could pave the way for easier and more accessible future personalised interval dosing of B-cell depleting therapies if this stability is confirmed in long-term treatment.

BACKGROUND:Extended interval dosing (EID) of natalizumab is increasingly used in clinical practice for patients with multiple sclerosis, driven by growing evidence supporting its sustained efficacy and associated benefits. However, it remains unclear whether EID, particularly at dosing intervals beyond six weeks, affects treatment satisfaction. OBJECTIVES:To investigate whether natalizumab dosing intervals of up to ten weeks are associated with patient-reported treatment satisfaction. METHODS:Participants from the prospective NEXT-MS and SUPERNEXT trials, both evaluating concentration-guided EID while preserving therapeutic drug concentrations, completed longitudinal Treatment Satisfaction Questionnaire for Medication (TSQM) assessments. Associations between dosing interval and scores in the four TSQM domains (Effectiveness, Side effects, Convenience, and Overall satisfaction) were analyzed using linear mixed-effects models. RESULTS:A total of 427 participants were included. Most participants reported high treatment satisfaction. No overall association was observed between dosing interval and TSQM scores. However, additional effect-modification analyses suggested that the association between dosing interval and treatment satisfaction differed according to treatment duration, disease duration, baseline EDSS, and route of natalizumab administration. CONCLUSIONS:Treatment satisfaction was high and was not affected by longer dosing intervals in the majority of patients. However, additional effect-modification analyses indicated that the impact of dosing interval on treatment satisfaction may differ according to patient characteristics, highlighting the importance of individualized treatment decisions.

Background Natalizumab is a highly effective drug for patients with relapsing-remitting multiple sclerosis (MS). A disadvantage of this treatment is the risk of progressive multifocal leukoencephalopathy in patients who are seropositive for the John Cunningham virus (JCV). JCV seroconversion rates increase under natalizumab treatment compared with non-natalizumab using controls. The aim of this study was to assess whether lower natalizumab trough concentrations are associated with reduced JCV seroconversion compared with higher natalizumab trough concentrations. Methods Two overlapping cohorts of patients treated with intravenous natalizumab in the Netherlands were combined for this study. JCV seroconversion was assessed during periods of high (≥15 µg/mL) and low (<15 µg/mL) natalizumab trough concentrations. Low trough concentrations were mainly the result of trough concentration guided personalised extended interval dosing (EID). The seroconversion rates during high and low trough concentrations were compared using a generalised linear mixed model with a Poisson link function. Results A total of 357 patients from 21 hospitals in the Netherlands were included. The annual seroconversion rate of 8.4% observed in patients during periods of high trough concentrations (n=226) was 2.32 times higher than the seroconversion rate of 4.8% in patients during periods of low trough concentrations (n=252) (95% CI=1.32 to 4.08, p=0.0035). Conclusions The seroconversion rate observed in patients with MS with low trough concentrations was substantially lower compared with those with high trough concentrations during natalizumab treatment. This emphasises the importance of personalised EID, where intervals between infusions are prolonged to achieve lower natalizumab trough concentrations, to increase drug safety.

BACKGROUND:Biomarkers of neuronal and axonal damage (serum neurofilament light (sNfL) and serum glial fibrillary acidic protein (sGFAP)) may provide insight into the aetiology of natalizumab wearing-off symptoms (WoSs). OBJECTIVES:We investigated the longitudinal association between and predictive value of sNfL and sGFAP and the occurrence of WoS in MS patients treated with natalizumab. METHODS:We performed longitudinal measurements of sNfL and sGFAP in NEXT-MS trial participants who completed a questionnaire about WoS. RESULTS:A total of 364 participants were included. In total, 55.5% presented with WoS and 44.5% without WoS during natalizumab treatment. Longitudinal analyses showed no association between sNfL and sGFAP levels and WoS at any timepoint. Biomarker levels at baseline did not predict first-time WoS occurrence. CONCLUSION:Acute and chronic neuronal and axonal damage are most likely not the underlying cause of WoS.

Background Extended interval dosing (EID) of natalizumab is a promising strategy to optimise treatment in multiple sclerosis (MS). Personalised EID by therapeutic drug monitoring can enable further extension of treatment intervals. Methods The NEXT-MS trial is an investigator-initiated prospective phase IV non-randomised study. Adults with a diagnosis of relapsing-remitting MS who received ≥6 natalizumab infusions were included in three groups: personalised EID with a target drug trough concentration of 10 µg/mL (EID10), an exploratory group of personalised EID with a target of 5 µg/mL (EID5) and standard interval dosing (SID) of 4 weeks. The primary outcome is radiological disease activity (new/newly enlarged T2 lesions) comparing the EID10 group to a historical cohort of SID (HSID). Results Results of the first phase of the NEXT-MS trial are reported here (n=376) as the study will continue with an amended protocol. In the EID10 group (n=251), incidence rate of radiological activity was 10.0 per 1000 person-years, which was non-inferior to the HSID cohort (24.7 per 1000 person-years (n=87), incidence rate difference 14.7, 90% CI −4.5 to 34.0). Incidence rate of radiological activity was 10.0 per 1000 person-years in the EID5 group (n=65), and 47.0 per 1000 person-years in the SID group (n=60). Serum neurofilament light levels did not increase over time within the EID groups. There were no cases of progressive multifocal leukoencephalopathy. Conclusions MS disease activity is adequately controlled with personalised natalizumab EID. Interval extension to a drug trough concentration of 5 µg/mL is likely a safe target to extend natalizumab treatment intervals >6 weeks. Trial registration number NCT04225312 .

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.

Chemotherapy-induced peripheral neuropathy (CIPN) may negatively influence multiple myeloma (MM) patients’ health-related quality of life (HRQOL). Dose modification is the only way to minimize CIPN. To measure CIPN in daily practice, the Indication for Common Toxicity Criteria (CTC) Grading of Peripheral Neuropathy Questionnaire (ICPNQ) was developed which can be completed within five minutes by the patient. The aims of this study were to (1) perform a psychometric evaluation of the ICPNQ and (2) examine the prevalence of CIPN and its influence on HRQOL in population-based MM patients.

IgM antibodies against gangliosides and their complexes were studied in sera from 54 patients with polyneuropathy and IgM monoclonal gammopathy (IgM-PNP) without anti-MAG antibodies. Anti-ganglioside antibodies were found in 19 (35%) patients. Five (9%) patients had antibodies against ganglioside complexes. IgM antibodies against gangliosides activated complement in vitro. Light chain usage was restricted to kappa or lambda in most, but not all patients. In conclusion, anti-ganglioside antibodies in IgM-PNP are common, display pathogenic properties and do not always arise from a monoclonal B cell proliferation.

The Medical Research Council grading system has served through decades for the evaluation of muscle strength and has been recognized as a cardinal feature of daily neurological, rehabilitation and general medicine examination of patients, despite being respectfully criticized due to the unequal width of its response options. No study has systematically examined, through modern psychometric approach, whether physicians are able to properly use the Medical Research Council grades. The objectives of this study were: (i) to investigate physicians' ability to discriminate among the Medical Research Council categories in patients with different neuromuscular disorders and with various degrees of weakness through thresholds examination using Rasch analysis as a modern psychometric method; (ii) to examine possible factors influencing physicians' ability to apply the Medical Research Council categories through differential item function analyses; and (iii) to examine whether the widely used Medical Research Council 12 muscles sum score in patients with Guillain-Barre syndrome and chronic inflammatory demyelinating polyradiculoneuropathy would meet Rasch model's expectations. A total of 1065 patients were included from nine cohorts with the following diseases: Guillain-Barre syndrome (n = 480); myotonic dystrophy type-1 (n = 169); chronic inflammatory demyelinating polyradiculoneuropathy (n = 139); limb-girdle muscular dystrophy (n = 105); multifocal motor neuropathy (n = 102); Pompe's disease (n = 62) and monoclonal gammopathy of undetermined related polyneuropathy (n = 8). Medical Research Council data of 72 muscles were collected. Rasch analyses were performed on Medical Research Council data for each cohort separately and after pooling data at the muscle level to increase category frequencies, and on the Medical Research Council sum score in patients with Guillain-Barre syndrome and chronic inflammatory demyelinating polyradiculoneuropathy. Disordered thresholds were demonstrated in 74-79% of the muscles examined, indicating physicians' inability to discriminate between most Medical Research Council categories. Factors such as physicians' experience or illness type did not influence these findings. Thresholds were restored after rescoring the Medical Research Council grades from six to four options (0, paralysis; 1, severe weakness; 2, slight weakness; 3, normal strength). The Medical Research Council sum score acceptably fulfilled Rasch model expectations after rescoring the response options and creating subsets to resolve local dependency and item bias on diagnosis. In conclusion, a modified, Rasch-built four response category Medical Research Council grading system is proposed, resolving clinicians' inability to differentiate among its original response categories and improving clinical applicability. A modified Medical Research Council sum score at the interval level is presented and is recommended for future studies in Guillain-Barre syndrome and chronic inflammatory demyelinating polyradiculoneuropathy.

Background: The disease course of polyneuropathy associated with immunoglobulin M monoclonal gammopathy (IgM MGUSP) can be highly variable. In order to identify factors that influence long-term disease outcome, a prospective cohort study was performed of 140 patients with IgM MGUSP over a period of 23 years.Methods: All patients with IgM MGUSP who were diagnosed in our tertiary referral center for polyneuropathy were eligible. All patients underwent nerve conduction studies and were tested for anti-MAG antibodies. The modified Rankin Scale, graded muscle strength, quantified sensory function, and laboratory testing were performed at 0, 1, 2, and 5 years and at last visit. The primary outcome measure was the risk of developing a modified Rankin Scale score of >= 3 points.Results: A total of 140 patients with IgM MGUSP fulfilled inclusion criteria (101 [72%] demyelinating, 39 [28%] axonal, 63 [44%] MAG positive). The median age at onset was 59 years (interquartile range 52-67), median disease duration at baseline was 3.2 years (interquartile range 1.9-6). Anti-MAG antibodies were associated with a lower risk of Rankin Scale score >= 3. Demyelination and a higher age at onset were associated with a higher risk for Rankin Scale score >= 3. Based on these 3 factors, a Web-based prognostic model was developed that directly allows clinicians to estimate the probability of developing disability (http://www.umcutrecht.nl/subsite/Prognosis-MGUS-Neuropathy).Conclusion: Higher age at onset and demyelination increase the risk, whereas anti-MAG antibodies decrease the risk, of developing Rankin Scale score >= 3 in polyneuropathy associated with immunoglobulin M monoclonal gammopathy (IgM MGUSP). Our Web-based prognostic model allows determination of prognosis in IgM MGUSP. Neurology(R) 2010;74:406-412

Background: Detection of serum antibodies to myelin-associated glycoprotein (MAG) by Western blot (WB) is a valuable assay to diagnose a distinct type of demyelinating polyneuropathy with immunoglobulin M (IgM) monoclonal gammopathy. In this study, the diagnostic accuracy of a new and more practical ELISA to detect these antibodies was validated. Methods: Routine WBs from 2 independent laboratories and ELISA were used to detect anti-MAG IgM in serum from 207 patients with neuropathy and controls. The sensitivity and specificity of these assays were compared and related to the patient clinical and electrophysiologic characteristics. Results: In ELISA, anti-MAG antibodies were found in serum from 49 (72%) of 68 patients with demyelinating polyneuropathy and IgM monoclonal gammopathy. However, in this subgroup of patients, only 30 (44%) and 37 (54%) were positive in the 2 WBs. All of the patients positive in the 2 WBs were also positive in ELISA. A high correlation was found for IgM activity in ELISA to MAG and sulfate-3-glucuronyl paragloboside (SGPG) (Spearman ρ = 0.72, p < 0.0001), supporting the notion that the shared sulfated glucuronic acid moiety of MAG and SGPG is preserved. Most patients positive in anti-MAG ELISA had a slowly progressive sensory–motor demyelinating polyneuropathy, even if the WB was negative. In control groups, however, 4 WB-negative patients with a nondemyelinating monoclonal gammopathy–related polyneuropathy were positive in anti-MAG ELISA. The remaining samples were negative in ELISA. Conclusion: ELISA is more sensitive than Western blot to diagnose anti–myelin-associated glycoprotein related polyneuropathy, although a positive serology may be found in other forms of polyneuropathy as well.

Background: Polyneuropathy with IgM monoclonal gammopathy can be a disabling disorder necessitating treatment. Methods: In a prospective open label trial, 17 patients with disabling IgM MGUS polyneuropathy were treated with rituximab, a chimeric anti-CD-20 monoclonal antibody. Results: Rituximab induced an improvement of ⩾1 point on the Overall Disability Sum Score in 2/17 patients, an improvement of ⩾5% of the distal MRC sum score in 4/17 and the sensory sum score in 9/17 patients. Bone marrow investigations showed CD 20 B cell depletion in all patients. There were no serious adverse events. Compared with treatment with intermittent cyclophosphamide with prednisone or treatment with fludarabine, it shows a comparable response percentages but fewer side effects. The presence of anti-MAG and a disease duration shorter than 10 years may predict treatment response. Conclusion: Rituximab is a candidate for treatment of IgM MGUS polyneuropathy and should be further investigated in a double-blind randomised trial.

Background: The best treatment for polyneuropathy associated with IgM monoclonal gammopathy (MGUS) is unknown. Oral cyclophosphamide combined with prednisone showed limited efficacy in a previous open label pilot study. We therefore performed a double-blind, randomized, placebo- controlled study of combined oral cyclophosphamide and prednisone in IgM MGUS polyneuropathy.Methods: Thirty- five patients with progressive IgM MGUS polyneuropathy were included. After stratification for anti-MAG antibodies patients were randomized to oral cyclophosphamide 500 mg once daily for 4 days combined with oral prednisone 60 mg once daily for 5 days (treatment) (n = 16), or placebo (n = 19), repeated every 28 days for six times. Primary outcome was improvement of the Rivermead Mobility Index (RMI). Secondary outcomes were improvement of the modified Rankin scale, Medical Research Council and sensory sum scores, levels of M protein, EMG, and Short Form-36 scale after treatment. Patients were examined at 0, 6, 12, 18, and 24 months.Results: After 6 months of treatment and at later follow-up, no difference in change of the RMI between the two groups was observed. Change of the Rankin scale was similar in both groups. Other outcome parameters showed more improvement in the treatment group: the MRC sum score improved more from 6 to 24 months after treatment; the sensory sum score improved more at 6 months; the SF 36 mean health change score and physical role score improved more; and the median nerve distal conduction (abductor pollicis brevis muscle) improved more in the treatment group. The most common adverse event was nausea.Conclusions: Compared with placebo treatment, this first double-blind randomized trial with cyclophosphamide and prednisone in IgM MGUS polyneuropathy showed no beneficial effect on the functional scales, but a beneficial effect on muscle strength and sensation was observed.

The occurrence and nature of cytogenetic aberrations in polyneuropathy associated with IgM monoclonal gammopathy was determined. Therefore, interphase fluorescence in situ hybridization (FISH) was applied in 22 patients with polyneuropathy associated with IgM monoclonal gammopathy, multiplex ligation-dependent probe amplification (MLPA) assay in 18 of these patients and genome-wide-array-based comparative genomic hybridization (CGH) in eight of these 18 patients. Four patients had 10–20% and one patient had 30% B cells with IgH rearrangements; one patient had additional loss of 14qter; one patient had amplification of 6p and loss of 6q. Cytogenetic aberrations may be found in one third of the patients with neuropathy associated with IgM monoclonal gammopathy and are mainly associated with indolent Waldenstrom's Macroglobulinemia.