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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

TRIAL REGISTRATION NUMBER

NCT04225312.

High work absence around time of diagnosis of multiple sclerosis is associated with fatigue and relapse rate

BACKGROUND

Multiple sclerosis (MS) is associated with high rates of disability pension and work absence. Little is known about work absence in early MS. The objectives of this study were (1) to assess the prevalence of work absence shortly after MS diagnosis, (2) to explore health-related quality of life (HRQoL) and disease impact in relation to work absence and (3) to investigate demographic and clinical factors that may be associated with high work absence.

METHODS

Patients with relapsing remitting (RRMS) or primary progressive MS (PPMS) were included shortly after MS diagnosis. We collected data on work absence due to MS in the year prior to inclusion, disability (Expanded Disability Status Scale), relapse rate, fatigue (Neurological Fatigue Index), health-related quality of life (HRQoL, 36-Item Short Form Survey) and disease impact (Multiple Sclerosis Impact Scale). For analysis, patients were divided in 2 groups: low work absence (<1 month) and high work absence (≥1 month). Data was analyzed using backward logistic regression techniques.

RESULTS

In total, 90 MS patients participated (80 RRMS, 10 PPMS, mean age = 39.3 years, median disease duration since diagnosis = 0.5 year). Work absence in the year prior to inclusion was reported by 66 patients (73.3%). High work absence of ≥ 1 month was reported by 41 patients (45.6%). Disability, gender, age, disease duration and education did not differ between groups. Patients with high work absence reported a lower HRQoL and higher disease impact compared to patients with low work absence. Backward regression analysis showed that high work absence is associated with being single/not married, fatigue and relapses. The strongest association was found for fatigue (highest fatigue vs. lowest fatigue level: OR total group = 7.8, RRMS = 15.8). In RRMS patients the second-strongest association was relapse rate (≥2 relapses in the past year vs. no relapses: OR 11.1).

CONCLUSION

Prevalence of work absence is high in early MS. Patients with high work absence report a lower HRQoL and a higher disease impact. High work absence is associated with being single/not married, fatigue and relapses. Interventions aimed at fatigue and prevention of relapses may help maintain employment in early MS.

The fat embolism syndrome as a cause of paraplegia

The fat embolism syndrome is a well-known complication in trauma patients. We describe a rare case of traumatic fat embolism that leads to paraplegia. A 19-year-old male motorcycle accident victim was presented to our hospital. After stabilization and trauma survey, he was diagnosed with bilateral femur fractures, a spleen laceration and a tear in the inferior vena cava, for which damage control surgery was performed. Post-operatively, the patient became paraplegic and developed a fluctuating consciousness, respiratory distress and petechiae. Fat embolism syndrome was considered as the most plausible cause of the paraplegia. The fat embolism syndrome is seen in approximately 1% of trauma patients, mostly those with bilateral fractures of the femur. Prevention of the syndrome depends on early stabilization of fractures. However, even with optimal care, this syndrome can still occur and may have dramatic consequences, as we demonstrate in this case.

John Cunningham virus conversion in relation to natalizumab concentration in multiple sclerosis patients

BACKGROUND AND PURPOSE

Infection with the John Cunningham virus (JCV) is required for the development of progressive multifocal leukoencephalopathy, the feared complication of natalizumab treatment in multiple sclerosis patients. The JCV seroconversion rate seems higher in natalizumab treated patients than in the normal population, with an unknown cause.

METHODS

Natalizumab concentration was correlated to JCV antibody status and seroconversion in a large cohort of multiple sclerosis patients.

RESULTS

One hundred and thirty-five patients were included. No correlation was found between natalizumab concentration and JCV status, JCV seroconversion or JCV index.

CONCLUSIONS

Higher natalizumab concentrations do not explain the increased JCV seroconversion rate in natalizumab treated patients.

Natalizumab-associated progressive multifocal leukoencephalopathy is not preceded by elevated drug concentrations

Background:

In recent years, a small but increasing number of neurologists choose to extend dose intervals of natalizumab with the aim of reducing the risk of progressive multifocal leukoencephalopathy (PML). This idea is based on the hypothesis that high drug concentrations increase the risk of PML.

Objective:

We investigated the relation between longitudinal natalizumab concentrations in patients who developed PML and patients who did not develop PML.

Methods:

In a prospective observational cohort study of 219 patients with relapsing–remitting multiple sclerosis treated with natalizumab, serum samples were taken every 12 weeks prior to natalizumab infusion. In this cohort, 5 patients developed PML and were matched with 10 patients from the cohort who did not develop PML. Natalizumab concentrations were measured in available samples, and the longitudinal results were compared between the two patient groups.

Results:

Mean natalizumab concentrations in the five patients developing PML was 18.9 µg/mL (standard deviation (SD): ±13.4) versus 23.8 µg/mL (SD: ±11.5) of the control patients. Furthermore, we did not observe a clear rise in concentration levels in patients subsequently developing PML.

Conclusion:

Our results provide preliminary evidence that contradicts the hypothesis that exposure to elevated concentrations of natalizumab is a relevant risk factor of developing PML.

MRI criteria differentiating asymptomatic PML from new MS lesions during natalizumab pharmacovigilance

OBJECTIVE

Differentiation between progressive multifocal leukoencephalopathy (PML) and new multiple sclerosis (MS) lesions on brain MRI during natalizumab pharmacovigilance in the absence of clinical signs and symptoms is challenging but is of substantial clinical relevance. We aim to define MRI characteristics that can aid in this differentiation.

METHODS

Reference and follow-up brain MRIs of natalizumab-treated patients with MS with asymptomatic PML (n=21), or asymptomatic new MS lesions (n=20) were evaluated with respect to characteristics of newly detected lesions by four blinded raters. We tested the association with PML for each characteristic and constructed a multivariable prediction model which we analysed using a receiver operating characteristic (ROC) curve.

RESULTS

Presence of punctate T2 lesions, cortical grey matter involvement, juxtacortical white matter involvement, ill-defined and mixed lesion borders towards both grey and white matter, lesion size of >3 cm, and contrast enhancement were all associated with PML. Focal lesion appearance and periventricular localisation were associated with new MS lesions. In the multivariable model, punctate T2 lesions and cortical grey matter involvement predict for PML, while focal lesion appearance and periventricular localisation predict for new MS lesions (area under the curve: 0.988, 95% CI 0.977 to 1.0, sensitivity: 100%, specificity: 80.6%).

INTERPRETATION

The MRI characteristics of asymptomatic natalizumab-associated PML lesions proved to differ from new MS lesions. This led to a prediction model with a high discriminating power. Careful assessment of the presence of punctate T2 lesions, cortical grey matter involvement, focal lesion appearance and periventricular localisation allows for an early diagnosis of PML.

MRI characteristics of early PML-IRIS after natalizumab treatment in patients with MS

OBJECTIVE

The early detection of MRI findings suggestive of immune reconstitution inflammatory syndrome (IRIS) in natalizumab-associated progressive multifocal leukoencephalopathy (PML) is of crucial clinical relevance in terms of treatment decision-making and clinical outcome. The aim of this study was to investigate the earliest imaging characteristics of PML-IRIS manifestation in natalizumab-treated patients with multiple sclerosis and describe an imaging pattern that might aid in the early and specific diagnosis.

METHODS

This was a retrospective study assessing brain MRI of 26 patients with natalizumab-associated PML presenting with lesions suggestive of PML-IRIS during follow-up. MRI findings were evaluated considering the imaging findings such as mass effect, swelling, contrast enhancement, new perivascular T2 lesions and signs suggestive of meningeal inflammation.

RESULTS

Contrast enhancement was the most common imaging sign suggestive of PML-IRIS, seen in 92.3% of the patients (with patchy and/or punctuate pattern in 70.8% and 45.8% respectively), followed by new T2 lesions with a perivascular distribution pattern (34.6%). In those patients with contrast enhancement, the enhancement was present in the lesion periphery in 95.8% of the patients. Contrast-enhancing lesions with a perivascular distribution pattern outside of the PML lesion were observed in 33.3% of the patients. The most common overall pattern was contrast enhancement in the border of the PML lesion with either a patchy or punctuate appearance in 88.5% of all patients.

CONCLUSIONS

Contrast enhancement is the most common earliest sign of natalizumab-associated PML-IRIS with a frequent imaging pattern of contrast-enhancing lesions with either a patchy or punctuate appearance in the border of the PML lesion.

High cumulative JC virus seroconversion rate during long-term use of natalizumab

BACKGROUND AND PURPOSE

John Cunningham virus (JCV) seropositivity is a risk factor for the development of natalizumab-associated progressive multifocal leukoencephalopathy (PML) in multiple sclerosis (MS) patients. When JCV seronegative patients seroconvert, their risk of developing PML increases. Limited longitudinal data exist about the seroconversion rate amongst natalizumab-treated relapsing-remitting MS (RRMS) patients. Our objective was to evaluate the seroconversion rate in a large Dutch cohort of natalizumab-treated RRMS patients. Seroconversion was defined as at least two consecutive seropositive serum samples (or cessation of therapy after a single seropositive sample because of seropositivity) after initial seronegative testing.

METHODS AND RESULTS

In our study of 179 patients for whom longitudinal blood samples were available over a long period (median 4.2 years), anti-JCV antibody indices were measured in 933 available samples. Eighty-six patients (48.0%) tested seronegative initially. Of these 86 seronegative patients, 23 patients (26.7%) seroconverted during follow-up. The annualized seroconversion rate was 7.1%. Seroconversion occurred between 9 and 90 months (median 43 months) of treatment. The rate of seroconversion was independent of follow-up duration. No significant increase was seen in the anti-JCV antibody index in the non-converting patients during the follow-up.

CONCLUSION

The annualized seroconversion rate of 7.1% in patients using natalizumab, cumulatively leading to more than 25% of seronegative patients becoming seropositive in 4 years, is of clinical relevance and should be taken into account in the risk assessment when considering the start of natalizumab therapy.

Diagnostic performance of brain MRI in pharmacovigilance of natalizumab-treated MS patients

BACKGROUND

In natalizumab-treated multiple sclerosis (MS) patients, magnetic resonance imaging (MRI) is considered as a sensitive tool in detecting both MS disease activity and progressive multifocal leukoencephalopathy (PML).

OBJECTIVE

To investigate the performance of neuroradiologists using brain MRI in detecting new MS lesions and asymptomatic PML lesions and in differentiating between MS and PML lesions in natalizumab-treated MS patients. The secondary aim was to investigate interrater variability.

METHODS

In this retrospective diagnostic study, four blinded neuroradiologists assessed reference and follow-up brain MRI scans of 48 natalizumab-treated MS patients with new asymptomatic PML lesions (n = 21) or new MS lesions (n = 20) or no new lesions (n = 7). Sensitivity and specificity for detection of new lesions in general (MS and PML lesions), MS and PML lesion differentiation, and PML detection were determined. Interrater agreement was calculated.

RESULTS

Overall sensitivity and specificity for the detection of new lesions, regardless of the nature of the lesions, were 77.4% and 89.3%, respectively; for PML-MS lesion differentiation, 74.2% and 84.7%, respectively; and for asymptomatic PML lesion detection, 59.5% and 91.7%, respectively. Interrater agreement for the tested categories was fair to moderate.

CONCLUSION

The diagnostic performance of trained neuroradiologists using brain MRI in pharmacovigilance of natalizumab-treated MS patients is moderately good. Interrater agreement among trained readers is fair to moderate.

MRI pattern in asymptomatic natalizumab-associated PML

OBJECTIVE

To investigate the MRI manifestation pattern of asymptomatic natalizumab-associated progressive multifocal leukoencephalopathy (PML) in patients with multiple sclerosis (MS).

METHODS

18 patients with MS with natalizumab-associated PML lesions on MRI were included. In 6 patients, the PML lesions were identified on MRI prospectively and in 12 patients PML lesions were identified retrospectively. MRI sequences were analysed for PML lesion distribution, appearance, grey matter/white matter involvement and possible signs of inflammation. Lesion probability maps were created to demonstrate lesion distribution pattern.

RESULTS

The frontal lobe was involved in 14 patients (77.8%) and the parietal lobe in 4 patients (22.2%). Most patients presented with focal lesions (13 patients, 72.2%) involving one single lobe (12 patients, 66.7%). The cortical grey matter was affected in 15 patients (83.3%) and 13 patients (72.2%) presented with a combination of cortical grey and white matter involvement. Signs of inflammation were detected in 7 patients (38.8%). Among patients with available diffusion-weighted imaging, 6 patients (40%) did not show high-signal-intensity lesions. A classical imaging pattern including unilateral and unilobar focal lesions in the frontal lobe affecting the cortical grey matter or the cortical grey and adjacent white matter was observed in 8 patients (44.4%).

CONCLUSIONS

Asymptomatic natalizumab-associated PML manifestations on MRI show a rather localised disease, frequently located in the frontal lobes, affecting the cortical grey matter and adjacent juxtacortical white matter. Awareness of this lesion pattern facilitates an earlier diagnosis of natalizumab-associated PML in an asymptomatic stage associated with a more favourable prognosis.

Longitudinal JCV serology in multiple sclerosis patients preceding natalizumab-associated progressive multifocal leukoencephalopathy

The presence of anti-John Cunningham Virus (JCV) antibodies is a risk factor for the development of progressive multifocal leukoencephalopathy (PML) in MS patients treated with natalizumab. It has been suggested that an increase in serum anti-JCV antibody index precedes the development of PML. We here describe extensive longitudinal serum anti-JCV antibody indexes of four MS patients who developed PML. Anti-JCV antibodies were measured using the STRATIFY JCV™DxSelect™ test. All four patients had rather stable high anti-JCV antibody indexes in all samples obtained before developing PML. Possibly caused by reaching the saturation level of the assay, no increase in anti-JCV antibody indexes was seen just before the diagnosis of PML. This study confirms that high serum anti-JCV antibody indexes precede natalizumab-associated PML.

Application of serum natalizumab levels during plasma exchange in MS patients with progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a severe complication of natalizumab treatment. Restoring immune function by plasmapheresis/immunoadsorption (PLEX/IA) is important for the outcome of PML. We report on four multiple sclerosis (MS) patients whom developed PML during natalizumab treatment, in whom we measured serum natalizumab concentrations before and during PLEX. Depending on the serum natalizumab concentration at the time of PML diagnosis, the number of PLEX treatments necessary to reach subtherapeutic serum natalizumab concentrations is variable. Measuring serum natalizumab concentrations before and during PLEX is helpful to determine the optimum number of PLEX treatments in individual MS patients with PML.

The impact of pre-analytical variables on the stability of neurofilament proteins in CSF, determined by a novel validated SinglePlex Luminex assay and ELISA

BACKGROUND

Neurofilament (Nf) proteins have been shown to be promising biomarkers for monitoring and predicting disease progression for various neurological diseases. The aim of this study was to evaluate the effects of pre-analytical variables on the concentration of neurofilament heavy (NfH) and neurofilament light (NfL) proteins.

METHODS

For NfH an in-house newly-developed and validated SinglePlex Luminex assay was used; ELISA was used to analyze NfL.

RESULTS

For the NfL ELISA assay, the intra- and inter-assay variation was respectively, 1.5% and 16.7%. Analytical performance of the NfH SinglePlex Luminex assay in terms of sensitivity (6.6pg/mL), recovery in cerebrospinal fluid (CSF) (between 90 and 104%), linearity (from 6.6-1250pg/mL), and inter- and intra-assay variation (<8%) were good. Concentrations of both NfL and NfH appeared not negatively affected by blood contamination, repeated freeze-thaw cycles (up to 4), delayed processing (up to 24hours) and during long-term storage at -20°C, 4°C, and room temperature. A decrease in concentration was observed during storage of both neurofilament proteins up to 21days at 37°C, which was significant by day 5.

CONCLUSIONS

The newly developed NfH SinglePlex Luminex assay has a good sensitivity and is robust. Moreover, both NfH and NfL are stable under the most prevalent pre-analytical variations.

Safety, anxiety and natalizumab continuation in JC virus-seropositive MS patients

The use of natalizumab in multiple sclerosis has been restricted by the risk of progressive multifocal leukoencephalopathy (PML). JC virus carriership, duration of natalizumab treatment and past immunosuppression are known risk factors. This has allowed for calculated risk assessment for individual patients to be implemented. Not much data are available about the effect of JCV carriership on patient willingness to continue natalizumab. Here, we evaluated the impact of JCV seropositivity on safety feelings, anxiety and treatment continuation for patients treated with natalizumab, using a visual analog scale, the Hospital Anxiety and Depression Scale and a decisional conflict scale. Seropositivity led to an elevated anxiety level for PML (p = 0.004). However, so far only 3% of patients have discontinued natalizumab because of JCV positivity in our cohort.

Clinical relevance of serum natalizumab concentration and anti-natalizumab antibodies in multiple sclerosis

BACKGROUND

Antibodies against natalizumab have been found in 4.5-14.1% of natalizumab-treated multiple sclerosis (MS) patients. If antibodies persist, they are associated with an adverse effect on treatment response. However, it has proved to be difficult to standardize anti-drug antibody measurements.

OBJECTIVES

The purpose of this study was to evaluate the clinical and radiological impact of serum natalizumab concentrations and their relation with anti-natalizumab antibodies in MS patients.

METHODS

In this prospective observational cohort study of 73 consecutive patients treated with natalizumab, we measured serum natalizumab levels and antibody titers before the start of natalizumab treatment, at weeks 12 and 24 and annually after natalizumab initiation. Antibodies against natalizumab were measured by radioimmunoassay and serum natalizumab concentrations using a newly developed enzyme linked immunosorbent assay (ELISA). Magnetic resonance imaging (MRI) scan and clinical evaluation were performed before the start of natalizumab treatment and subsequently every year.

RESULTS

Antibodies were detected in 58% of the natalizumab-treated patients. All patients developed their antibodies before week 24. The large majority of these patients reverted to neutralizing antibody (NAb) negative status during follow-up. The presence of antibodies was inversely correlated with serum natalizumab concentration (p<0.001). Only high antibody titers are associated with very low or undetectable serum natalizumab concentration. Both high antibody titers and low serum natalizumab concentrations are associated with relapses and gadolinium-enhancing lesions on MRI.

CONCLUSIONS

Our data show that both low natalizumab serum concentration and high antibody titers are associated with a lack of efficacy of natalizumab. Measuring serum natalizumab, using a highly specific assay, might lead to more enhanced precision using natalizumab in individual patients.

Natalizumab remains detectable in patients with multiple sclerosis long after treatment is stopped

Natalizumab is frequently used as a treatment for multiple sclerosis (MS). The occurrence of progressive multifocal leukoencephalopathy (PML) in natalizumab-treated patients indicates that its prominent beneficial effects need to be balanced against the risks. Also, cessation of the drug seems to be associated with recurrence of disease activity. Both the moment of rebound disease activity and the outcome of PML are related to clearance of the drug. Specific features of this IgG4 antibody (i.e. half-antibody exchange) may result in underestimated drug levels. Here, we demonstrate natalizumab levels in 10 patients with relapsing MS, using a recently developed sensitive assay. Remarkably, natalizumab was detectable up to 200 days after cessation of therapy.

Antibodies against aquaporin-4 in neuromyelitis optica: distinction between recurrent and monophasic patients

The detection of antibodies against aquaporin-4 (AQP4) has improved the diagnosis of neuromyelitis optica (NMO). We evaluated a recently established cell-based anti-AQP4 assay in 273 patients with inflammatory CNS demyelination. The assay had a specificity of 99% and a sensitivity of 56% to detect all NMO patients and of 74% to detect the recurrent NMO patients, similar to the initial studies reported. AQP4 antibodies were absent in monophasic NMO patients, while samples in recurrent cases remained positive during follow-up. We conclude that the pathogenesis of monophasic NMO may be different from that of relapsing NMO.

Spontaneous MxA mRNA level predicts relapses in patients with recently diagnosed MS

OBJECTIVE

To determine if myxovirus resistance protein A (MxA) mRNA is related to clinical disease activity in multiple sclerosis (MS).

METHODS

Baseline MxA mRNA levels were measured in a prospective cohort of 116 untreated patients with early MS and were related to clinical relapses and MRI at baseline and at follow-up.

RESULTS

Low levels of MxA mRNA were associated with the occurrence of relapses (p = 0.002) and contrast-enhancing lesions (CELs) on baseline MRI (p = 0.045). In addition, high baseline MxA mRNA levels were related to a longer time to a first new relapse (hazard ratio [HR] 0.59; 95% confidence interval [CI] 0.35-1.00; p = 0.044). Adding the absence of CELs to high MxA mRNA, the predictive value increased (HR 0.35; 95% CI 0.17-0.74; p = 0.006), clearly showing a cumulative value for combining both factors.

CONCLUSIONS

MxA mRNA is related to clinical exacerbations, the number of CELs on MRI, and is indicative for the time to a subsequent relapse. If confirmed, MxA mRNA has potential as a biomarker for clinical disease activity in MS.