Serum neurofilament light for detecting disease activity in individual patients in multiple sclerosis: A 48-week prospective single-center study.

BACKGROUND: Serum neurofilament light (sNfL) reflects neuroaxonal damage and is now used as an outcome in treatment trials of relapsing-remitting multiple sclerosis (RRMS). However, the diagnostic properties of sNfL for monitoring disease activity in individual patients warrant further investigations. METHOD: Patients with suspected relapse and/or contrast-enhancing lesions (CELs) were consecutively included and performed magnetic resonance imaging (MRI) of the brain at baseline and weeks 28 and 48. Serum was obtained at baseline and 2, 4, 8, 16, 24, and 48 weeks. Neurofilament light concentration was measured using Single molecule array technology. RESULTS: We included 44 patients, 40 with RRMS and 4 with clinically isolated syndrome. The median sNfL level peaked at 2 weeks post-baseline (14.6 ng/L, interquartile range (IQR); 9.3-31.6) and reached nadir at 48 weeks (9.1 ng/L, IQR; 5.5-15.0), equivalent to the median sNfL of controls (9.1 ng/L, IQR; 7.4-12). A baseline Z-score of more than 1.1 (area under the curve; 0.78, p < 0.0001) had a sensitivity of 81% and specificity of 70% to detect disease activity. CONCLUSION: One out of five patients with relapse and/or CELs did not change significantly in post-baseline sNfL levels. The utility of repeated sNfL measurements to monitor disease activity is complementary rather than a substitute for clinical and MRI measures.

Effectiveness of first generation disease-modifying therapy to prevent conversion to secondary progressive multiple sclerosis.

BACKGROUND: The use of disease-modifying therapies (DMTs) in multiple sclerosis (MS) has been associated with reduced relapse rates and accumulation of disability. However, studies examining impact of DMT on risk of transition to secondary progressive MS (SPMS) leveraging population-based nationwide data are still rare. Here, we determine the population incidence of conversion to SPMS using two consecutive nation-wide cohorts, one immediately before and one after the introduction of DMT in Sweden. METHODS: We included two consecutive population cohorts of relapsing-remitting MS (RRMS) from the Swedish national MS register for the periods 1975-1994 (n = 2161), before DMT availability, and 1995-2011 (n = 3510), in which DMTs, mainly first generation DMT (injectables), became available and eventually were used by 70% of patients. We explored the risk of transition to SPMS as a calendar year function encompassing the two cohorts. In addition, we determined the incidence of transition to SPMS through age strata below and above 50 years in untreated and treated patient subgroups. RESULTS: The risk of conversion to SPMS (adjusted for current age, current time since onset, calendar year and sex) was significantly lower in the second compared with the first population cohort (hazard ratio 0.58; CI 0.48, 0.70). The risk of SPMS conversion per calendar year decreased by 2.6% annually (p < 0.001) after 1995. The risk of SPMS conversion increased with age until age 50. Thereafter, it was unchanged or decreased among those with early MS onset age (<35 years), but continued to increase with onset at higher age, with similar trends in treated and untreated subgroups. CONCLUSION: The incidence of SPMS conversion significantly decreased at the population level after introduction of first generation DMTs by 1995. DMT efficiency was confirmed by a downward turn of the annual trajectory of the risk of SPMS conversion after 1995. An onset age determined pattern of variable SPMS incidence in higher age appeared in both treated and untreated strata. While first generation DMT delayed conversion to SPMS, their long-term effect was only moderate.

NFL and CXCL13 may reveal disease activity in clinically and radiologically stable MS.

BACKGROUND: Cerebrospinal fluid (CSF) levels of neurofilament light (NFL), a biomarker of axonal damage, and CXCL13, a chemokine involved in B-cell regulation, are both associated with disease activity in multiple sclerosis (MS). OBJECTIVE: To explore the potential of NFL and CXCL13 to detect residual disease activity in patients with no signs of clinical or ongoing radiological activity and to study the clinical relevance of such activity. METHODS: NFL and CXCL13 concentrations were determined with ELISA in CSF obtained from 90 relapsing-remitting (RR) MS and 47 Progressive (Pr) MS (including primary and secondary PrMS) at baseline and after 12 months of follow-up. The patients were assessed at baseline, before initiating or switching disease modifying therapy (DMT) and again after 12 and 27 months of follow-up. RESULTS: All patients with ongoing disease activity (relapse or contrast-enhancing lesions on MRI) had increased NFL or CXCL13. The proportion of RRMS and PrMS patients without ongoing disease activity with elevation of either NFL or CXCL13 (residual disease activity) was 39% and 50%, respectively, and both were increased in 11% and 16%, respectively. The treatment with DMTs decreased the proportion with residual disease activity in both RRMS and PrMS significantly. We could not show any significant association between residual disease activity and clinical or MRI measures at 12 or 27 months of follow-up. CONCLUSIONS: Although most of this real-world study population had been treated with second-line DMTs and achieved clinical and radiological stability, a significant proportion of patients still displayed increased CSF levels of both NFL and CXCL13, indicating residual disease activity. Thus, these markers seemed considerably more sensitive to disease activity than clinical and MRI measures. However, the long-term clinical significance of such activity remains to be determined.

Natalizumab, rituximab and fingolimod as escalation therapy in multiple sclerosis.

BACKGROUND AND PURPOSE: Breakthrough disease on first-line injectables in relapsing-remitting multiple sclerosis (RRMS) is a common clinical situation where comparative studies between different escalation therapies are lacking. The aim of this study was to compare the efficacy, safety and medication persistence of natalizumab (NTZ), rituximab (RTX) and fingolimod (FGL) as escalation therapy in RRMS. METHODS: Patients switching from interferon or glatiramer acetate to NTZ, RTX or FGL due to breakthrough disease were identified through the Swedish multiple sclerosis (MS) registry at four large MS centers in this retrospective observational study. Data were collected from the MS registry and medical charts. Hazard ratios (HRs) for relapses, adverse events and drug discontinuation with 95% confidence interval (CI) were calculated using multivariable confounder-adjusted Cox proportional hazard models. RESULTS: A total of 241 patients were included. The annualized relapse rates were 0.02 for NTZ, 0.03 for RTX and 0.07 for FGL. Compared with NTZ, the adjusted HR for relapse was 1.0 (95% CI, 0.2-5.6) for RTX and 3.4 (95% CI, 1.3-9.2) for FGL. The annualized drug discontinuation rates were 0.15, 0.01 and 0.15 for NTZ, RTX and FGL, respectively. The adjusted HR for drug discontinuation was 0.05 (95% CI, 0.01-0.38) for RTX and 1.0 (95% CI, 0.6-1.7) for FGL vs. NTZ. CONCLUSIONS: In patients with RRMS on interferon/glatiramer acetate with breakthrough disease, switching to NTZ or RTX was associated with less disease activity compared with FGL. RTX displayed superior medication persistence compared with both NTZ and FGL.

Neurofilament light protein levels in cerebrospinal fluid predict long-term disability of Guillain-Barré syndrome: A pilot study.

OBJECTIVES: Although the recovery from Guillain-Barré syndrome (GBS) is good in most patients, some develop permanent severe disability or even die. Early predictors would increase the likelihood to identify patients at risk for poor outcome at the acute stage, allowing them intensified therapeutic intervention. MATERIALS AND METHOD: Eighteen patients with a history of GBS 9-17 years ago were reassessed with scoring of neurological disability and quality of life assessment (QoL). Their previous diagnostic work-up included clinical examination with scoring of disability, neurophysiological investigation, a battery of serology tests for infections, and cerebrospinal fluid (CSF) examination. Aliquots of CSF were frozen, stored for 20-28 years, and analyzed by ELISA for determination of neurofilament light protein (NFL) and glial fibrillary acidic protein (GFAP). RESULTS: Patients with poor outcome (n = 3) had significantly higher NFL and GFAP levels at GBS nadir than those with good outcome (n = 15, P < .01 and P < .05, respectively). High NFL correlated with more prominent disability and worse QoL at long-term follow-up (r = .694, P < .001, and SF 36 dimension physical component summary (PCS) (r =-.65, P < .05), respectively, whereas GFAP did not correlate with clinical outcome or QoL. CONCLUSION: High NFL in CSF at the acute stage of GBS seems to predict long-term outcome and might, together with neurophysiological and clinical measures, be useful in treatment decisions and clinical care of GBS.

A nationwide survey of the influence of month of birth on the risk of developing multiple sclerosis in Sweden and Iceland.

Previous studies have shown that the risk of multiple sclerosis (MS) is associated with season of birth with a higher proportion of MS patients being born in spring. However, this relationship has recently been questioned and may be due to confounding factors. Our aim was to assess the influence from season or month of birth on the risk of developing MS in Sweden and Iceland. Information about month of birth, gender, and phenotype of MS for patients born 1940-1996 was retrieved from the Swedish MS registry (SMSR), and their place of birth was retrieved from the Swedish Total Population Registry (TPR). The corresponding information was retrieved from medical journals of Icelandic MS patients born 1981-1996. The control groups consisted of every person born in Sweden 1940-1996, their gender and county of birth (TPR), and in Iceland all persons born between 1981 and 1996 and their gender (Statistics Iceland). We calculated the expected number of MS patients born during each season and in every month and compared it with the observed number. Adjustments were made for gender, birth year, and county of birth. We included 12,020 Swedish and 108 Icelandic MS patients in the analyses. There was no significant difference between expected and observed MS births related to season or month of birth in Sweden or Iceland. This was even the results before adjustments were made for birth year and birth place. No significant differences were found in subgroup analyses including data of latitude of birth, gender, clinical phenotype, and MS onset of 30 years or less. Our results do not support the previously reported association between season or month of birth and MS risk. Analysis of birth place and birth year as possible confounding factors showed no major influence of them on the seasonal MS risk in Sweden and Iceland.

Trials of antivirals in the treatment of multiple sclerosis.

There is increasing evidence that human herpes viruses and human endogenous retroviruses (HERV) are involved in the aetiology and pathogenesis of multiple sclerosis (MS). In order to acquire the ultimate evidence to confirm such a relationship, it is probably required to use specific antiviral drugs in clinical trials of MS. The results of published antiviral clinical trials in patients with MS are summarized in this review. None of them showed statistically significant effects on primary outcomes of disease activity or on disability development. However, given their small sample sizes, the strong trends and effects observed in subgroup analysis of antiherpes virus treatment in patients with MS warrant further studies. The possible involvement of HERV in MS is intriguing, and drugs have been developed that could reduce the impact of HERV in MS. However, larger studies are needed as the phase I and II trials were not designed to show clinical efficacy in MS.

Guidelines for the use of magnetic resonance imaging in diagnosing and monitoring the treatment of multiple sclerosis: recommendations of the Swedish Multiple Sclerosis Association and the Swedish Neuroradiological Society.

Multiple sclerosis (MS) is associated with inflammatory lesions in the brain and spinal cord. The detection of such inflammatory lesions using magnetic resonance imaging (MRI) is important in the consideration of the diagnosis and differential diagnoses of MS, as well as in the monitoring of disease activity and predicting treatment efficacy. Although there is strong evidence supporting the use of MRI for both the diagnosis and monitoring of disease activity, there is a lack of evidence regarding which MRI protocols to use, the frequency of examinations, and in what clinical situations to consider MRI examination. A national workshop to discuss these issues was held in Stockholm, Sweden, in August 2015, which resulted in a Swedish consensus statement regarding the use of MRI in the care of individuals with MS. The aim of this consensus statement is to provide practical advice for the use of MRI in this setting. The recommendations are based on a review of relevant literature and the clinical experience of workshop attendees. It is our hope that these recommendations will benefit individuals with MS and guide healthcare professionals responsible for their care.

Minocycline added to subcutaneous interferon ß-1a in multiple sclerosis: randomized RECYCLINE study.

BACKGROUND AND PURPOSE: Combining different therapies may improve disease control in patients with relapsing-remitting multiple sclerosis (RRMS). This study assessed the efficacy and safety of minocycline added to subcutaneous (sc) interferon (IFN) ß-1a therapy. METHODS: This was a double-blind, randomized, placebo-controlled multicentre study. Within 3 months (±1 month) of starting sc IFN ß-1a 44 µg three times weekly, patients with RRMS were randomized to minocycline 100 mg twice daily or placebo, added to sc IFN ß-1a, for 96 weeks. The primary efficacy endpoint was the time to first qualifying relapse. Secondary efficacy endpoints were the annualized relapse rate for qualifying relapses, the number of new/enlarging T2-weighted lesions and change in brain volume [magnetic resonance imaging (MRI) was performed only in a few selected centres]. In addition, a number of tertiary efficacy endpoints were assessed. RESULTS: One hundred and forty-nine patients received minocycline and 155 received placebo; MRI data were available for 23 and 27 patients, respectively. The time to first qualifying relapse did not differ significantly for minocycline versus placebo (hazard ratio 0.85; 95% confidence interval 0.53, 1.35; log-rank = 0.50; P = 0.48). There were no statistically significant differences between the two groups on other efficacy endpoints, although some numerical trends in favour of minocycline were observed. No unexpected adverse events were reported, but more patients discontinued because of adverse events with minocycline versus placebo. CONCLUSION: Minocycline showed no statistically significant beneficial effect when added to sc IFN ß-1a therapy.

Rituximab treatment did not aggravate ongoing progressive multifocal leukoencephalopathy in a patient with multiple sclerosis.

A multiple sclerosis (MS) patient developed progressive multifocal leukoencephalopathy (PML) after 43 months of natalizumab treatment. New clinical and magnetic resonance imaging (MRI) findings were initially misinterpreted as breakthrough MS disease activity and natalizumab treatment was replaced by rituximab treatment. The patient had a single infusion of rituximab 1000 mg before a definite PML diagnosis was confirmed. Despite undetectable levels of B-cells, JC virus DNA became undetectable in the cerebrospinal fluid by quantitative polymerase chain reaction. The patient partially recovered without any clinical or MRI signs of new MS activity. These findings suggest that B-cell depletion in a non-immune compromised individual did not prevent the patient from clearing the JC virus infection.

Neurofilament light and heavy subunits compared as therapeutic biomarkers in multiple sclerosis.

BACKGROUND: Neurofilaments are promising biomarkers in multiple sclerosis (MS) and increased levels in cerebrospinal fluid (CSF) indicate axonal damage or degeneration. In a previous study, neurofilament light chain (NfL) levels in CSF of relapsing remitting (RR) patients with MS were normalized by natalizumab treatment. AIMS OF THE STUDY: We compared the coherence between NfL and neurofilament heavy chain (NfH(SMI) (35) ) levels in longitudinal CSF samples in a subset of these patients. METHODS: In 30 patients with RRMS, CSF was obtained prior to and following 12 months of natalizumab treatment. NfH(SMI) (35) was measured by an electrochemiluminescence-based immunoassay. NfL levels were determined previously by the UmanDiagnostics NF-light(®) assay. RESULTS: NfH(SMI) (35) decreased in 73.3% and NfL in 90% of the patients following natalizumab treatment (32.4 vs 27.4 pg/ml, P = 0.002 and 820 vs 375 pg/ml, P < 0.0001). Patients experiencing a relapse showed higher NfH(SMI) (35) levels compared with patients in remission (47.7 vs 27.6 pg/ml, n = 8, P = 0.001). This difference was less obvious for NfL (1055 vs 725 pg/ml, P = 0.256). In patients in remission, NfL levels were lower following natalizumab treatment (830 vs 365 pg/ml, n = 20, P = 0.0002), whereas the same comparison failed significance for NfH(SMI) (35) (28.3 vs 26.9 pg/ml, P = 0.086). CONCLUSIONS: We confirm previous findings, indicating reduced axonal damage under natalizumab treatment by measuring NfH(SMI) (35) , using an assay with independent methodology. In comparison with NfH(SMI) (35) , NfL changes were more pronounced and the treatment effect also included patients in remission. Our results suggest that NfL is superior over NfH(SMI) (35) as therapeutic biomarker and is a promising candidate to measure neuroaxonal damage in MS treatment trials.

Time to secondary progression in patients with multiple sclerosis who were treated with first generation immunomodulating drugs.

BACKGROUND: It is currently unknown whether early immunomodulatory treatment in relapsing-remitting MS (RRMS) can delay the transition to secondary progression (SP). OBJECTIVE: To compare the time interval from onset to SP in patients with RRMS between a contemporary cohort, treated with first generation disease modifying drugs (DMDs), and a historical control cohort. METHODS: We included a cohort of contemporary RRMS patients treated with DMDs, obtained from the Swedish National MS Registry (disease onset between 1995-2004, n = 730) and a historical population-based incidence cohort (onset 1950-64, n = 186). We retrospectively analyzed the difference in time to SP, termed the "period effect" within a 12-year survival analysis, using Kaplan-Meier and Cox regression analysis. RESULTS: We found that the "period" affected the entire severity spectrum. After adjusting for onset features, which were weaker in the contemporary material, as well as the therapy initiation time, the DMD-treated patients still exhibited a longer time to SP than the controls (hazard ratios: men, 0.32; women, 0.53). CONCLUSION: Our results showed there was a longer time to SP in the contemporary subjects given DMD. Our analyses suggested that this effect was not solely driven by the inclusion of benign cases, and it was at least partly due to the long-term immunomodulating therapy given.

High nationwide prevalence of multiple sclerosis in Sweden.

BACKGROUND: Few nationwide multiple sclerosis (MS) prevalence studies have been published. In Scandinavia, the nationwide MS prevalence was 173/100,000 in Denmark 2005 and 100/100,000 in Iceland 1990. OBJECTIVE: Our aim with the present study was to determine the first population-based nationwide MS prevalence in Sweden, based on observed, registered patients and to investigate the presence of a north-south gradient of MS prevalence. METHODS: By linking the Swedish National Patient Register, the Swedish Multiple Sclerosis Registry and the Swedish Total Population Register we obtained the number of patients who were diagnosed with MS before 2009, and who were registered, alive and resident in Sweden on the prevalence date 31 December 2008. We calculated the gender-specific nationwide MS prevalence in 1-year age intervals. The relationship between MS risk and latitude was studied in a logistic regression model including all individuals in the population of Sweden. RESULTS: The number of registered MS patients in 2008 was 17,485 out of the Swedish population of 9,256,347. The overall MS prevalence was 188.9/100,000 (95% CI 186.1-191.7), 113.4 (95% CI 110.3-116.5) for men and 263.6 (95% CI 258.9-268.3) for women. The female to male ratio was 2.35:1. The prevalence of MS significantly increased for each degree of north latitude with 1.5% in men (p = 0.013) and 1% in women (p = 0.015). CONCLUSIONS: The MS prevalence of 188.9/100,000 in Sweden is among the highest nationwide prevalence estimates in the world. In Sweden, the risk of MS increases with increasing north latitude for both men and women.

Glial fibrillary acidic protein: a potential biomarker for progression in multiple sclerosis.

The major intermediate cytoskeletal protein of astrocytes, glial fibrillary acidic protein (GFAP), and that of axons, neurofilament light protein (NFL), may both be released into the cerebrospinal fluid (CSF) during pathological processes in the central nervous system (CNS). We investigated GFAP and NFL levels in CSF as possible biomarkers for progression in multiple sclerosis (MS). Patients with relapsing-remitting MS (RRMS, n = 15) or secondary progressive MS (SPMS, n = 10) and healthy control subjects (n = 28) were examined twice with an interval of 8-10 years apart. Neurological deficits were scored with the Expanded Disability Status Scale (EDSS). GFAP and NFL levels were determined in CSF by enzyme-linked immunosorbent assay (ELISA). GFAP levels and NFL levels correlated with age (r and r (s) = 0.50, p = 0.006). Adjusting for age, MS patients had increased GFAP levels compared with controls (p = 0.03) and GFAP levels correlated with neurological disability (EDSS, r = 0.51, p < 0.05) and disease progression [Multiple Sclerosis Severity Score (MSSS), r = 0.47, p < 0.05]. The mean annual increase of GFAP was 6.5 ng/L for controls, 8.1 ng/L for RRMS patients, and 18.9 ng/L for SPMS patients. GFAP level at the first examination had predictive value for neurological disability 8-10 years later (EDSS, r = 0.45, p < 0.05) but not for EDSS increase between the examinations. NFL levels were not significantly increased in MS patients compared with controls and had no relationship to disability or progression and no prognostic value for disability development. GFAP, a marker for astrogliosis, is a potential biomarker for MS progression and may have a role in clinical trials for assessing the impact of therapies on MS progression.

High risk of MS in Iranian immigrants in Gothenburg, Sweden.

BACKGROUND: In this study we investigated the risk of multiple sclerosis (MS) in migrants who had moved from Iran to Gothenburg, Sweden. METHODS: Patients born in Iran were retrieved from a population-based cohort, which included 534 MS and clinically isolated syndrome patients, born 1959-1990, aged 10-39 years at disease onset in Gothenburg. The expected versus observed number of migrants from Iran was calculated. RESULTS: The MS risk in the Iranian migrants in Gothenburg was several times higher than in Isfahan, Iran (hazard ratio 3.88, 95% confidence interval 2.17-6.40). Compared with the general population of Gothenburg, the observed number of 17 Iranian patients was higher than the expected value of 9.89 (hazard ratio 1.72, 95% confidence interval 1.00-2.75). CONCLUSION: Migration from a medium-risk to a high-risk area may increase the MS risk to that of the high-risk area.

Reduced cerebrospinal fluid BACE1 activity in multiple sclerosis.

BACKGROUND: Cell and animal experiments have shown that beta-site APP-cleaving enzyme 1 (BACE1) may be involved in myelination. OBJECTIVE: Here, we assess the association of cerebrospinal fluid (CSF) BACE1 activity with multiple sclerosis (MS). METHODS: BACE1 activity and levels of secreted amyloid precursor protein (APP) and amyloid-beta (Abeta) isoforms were analyzed in CSF from 100 patients with MS and 114 neurologically healthy controls. Patients with systemic lupus erythematosus (SLE), 26 with and 41 without cerebral engagement, were also included to enable comparisons with regards to another autoimmune disease. A subset of patients with MS and controls underwent a second lumbar puncture after 10 years. RESULTS: MS patients had lower CSF BACE1 activity than controls (P = 0.03) and patients with cerebral SLE (P < 0.001). Patients with cerebral SLE had higher BACE1 activity than any other group (P < 0.05 for all comparisons). BACE1 activity correlated with the different amyloid markers in all study groups. BACE1 activity decreased over 10 years in the MS group (P = 0.039) and correlated weakly with clinical disease severity scores in an inverse manner. CONCLUSIONS: These results suggest an involvement of BACE1 in the MS disease process.

IL-6 and CCL2 levels in CSF are associated with the clinical course of MS: implications for their possible immunopathogenic roles.

Biological markers would provide valuable tools for tracking disease activity, immunopathological processes or therapeutic efficacy in MS. In this study we analysed a panel of Th(1)/Th(2) cytokines and the chemokine CCL2 in serum and CSF from MS patients and healthy controls. Increased levels of IL-6 (p<0.05) and decreased levels of CCL2 (p<0.001), with the lowest levels during acute relapses, was found in CSF from patients with relapsing-remitting MS. CSF levels of CCL2 correlated with indices for intrathecal IgG production and the CSF level of the neurofilament light protein, a marker for axonal damage, indicating a immunopathogenic role for CCL2.

Neurofilament light protein and glial fibrillary acidic protein as biological markers in MS.

OBJECTIVE: To determine if CNS-derived proteins present in the CSF of multiple sclerosis (MS) patients reflect different pathologic processes of MS and if these proteins could be useful as biologic markers of disease activity. METHODS: Concentrations of the neurofilament light protein (NFL), glial fibrillary acidic protein (GFAP), S100B, and the neuron-specific enolase protein (NSE) were determined in the CSF of 66 MS patients and 50 healthy control subjects with immunoassays. RESULTS: The mean levels of the NFL were increased during all stages of MS compared with controls (p < 0.001), peaking almost 10 times higher during acute relapses. The highest levels of GFAP were found during the secondary progressive course (p < 0.001) with a strong correlation with neurologic deficits (Expanded Disability Status Scale score, r = 0.73, p < 0.001). No increase of S100B or NSE protein was found in the CSF of MS patients compared with control subjects. CONCLUSIONS: Increased level of NFL is a general feature of MS, indicating continuous axonal damage during the entire course of the disease with the most profound damage during acute relapses. GFAP may serve as a biomarker for disease progression, probably reflecting the increasing rate of astrogliosis.

A randomized, double-blind, placebo-controlled MRI study of anti-herpes virus therapy in MS.

OBJECTIVE: To evaluate the effect of treatment with the antiherpes drug valacyclovir on MRI-evident lesions in patients with relapsing-remitting MS in a phase 2, randomized, double-blind, placebo-controlled study. BACKGROUND: It has been postulated from virologic studies that herpesvirus infection could play a role in the progression of MS. METHODS: Patients were eligible for the study if they had had two or more MS relapses in the 2-year period before enrollment. Seventy patients with Expanded Disability Status Scale scores of 0 to 5.5 were randomly assigned to receive 1 gram of valacyclovir (n = 36) or placebo (n = 34) three times daily for 24 weeks. Patients underwent MRI every fourth week for 32 weeks: twice during pretreatment, six times during treatment, and once after treatment. Scoring of neurologic disability was performed at the start and end of the treatment period. The primary endpoint was the number of new active MRI-evident lesions over 24 weeks of treatment. Secondary endpoints included other MRI measures and clinical endpoints. RESULTS: The mean number of new active lesions +/- SD per patient during 24 weeks of treatment with valacyclovir was 11.9 +/- 17.6 and that during placebo treatment was 14.5 +/- 21.4. A protocol-planned exploratory analysis stratified patients according to baseline activity; this analysis showed that patients with high levels of disease activity in the valacyclovir treatment group (n = 17) developed fewer new active lesions per scan than did those in the placebo treatment group (n = 11). The median number (Q(1), Q(3) range) of active lesions was 2.0 (1.38, 3.96) in the valacyclovir treatment group and 6.5 (2.63, 9.0) in the placebo treatment group. CONCLUSIONS: Valacyclovir treatment did not reduce the formation of active lesions in patients with relapsing-remitting MS who had two or more relapses during the previous 2-year period. In a subgroup of patients with high levels of disease activity who had more than one active MRI-evident lesion during 4 weeks, valacyclovir treatment was associated with a reduced number of new active MRI-evident lesions and with an increase in the number of scans free of new active lesions. The results of the exploratory subgroup analysis provide support for further studies of antiherpes therapy for patients with MS and high levels of MRI-evident disease activity.

Asymptomatic visual loss in multiple sclerosis.

Visual disturbances are common in multiple sclerosis (MS) and often a result of acute demyelinating optic neuropathy. Careful examination of MS patients, who have never suffered optic neuritis, may also reveal asymptomatic visual loss. This type of silent disease activity was investigated by computerised resolution perimetry, which has the potential to reflect the percentage of functional retino-cortical neural channels. The time of onset and the evolution of asymptomatic visual loss was investigated. One approach was to retrospectively select patients who never had suffered acute optic neuritis from a closely monitored MS population and re-examine them again. Sixteen patients were identified and vision was evaluated during a period of 5.5-9 years of follow-up and compared with that in 14 healthy controls. The mean channel percentage of the MS group was 89 +/- 19 % (SD) on entry into the study, compared with 110 +/- 15% (SD) of controls (p < 0.003). At termination of the study the mean percentage was essentially unchanged both in MS patients (87 +/- 21%, SD) and controls (110 +/- 19%, SD). The second approach was to test a group of 7 patients with MS or strongly suspected MS, with the same method, in close connection with their first clinical exacerbation. All cases lacked visual symptoms and none had previously had acute visual loss. Again, virtually all performed subnormally in the vision tests, and to the same degree as in the first group of patients. Results were compared with those obtained from 25 MS patients who had experienced one or more attacks of optic neuritis. Compared with controls the loss of functional retino-cortical neural channels was 20% in patients without a previous history of optic neuritis and 30 % in patients who previously had experienced optic neuritis. We conclude that asymptomatic visual loss seems to be a universal feature of MS and has a substantial impact on the visual pathways, that it is present already at the time of clinical onset of the disease, and that any progression thereafter is slow enough to elude detection during several years of follow-up.