The incidence and significance of anti-natalizumab antibodies: results from AFFIRM and SENTINEL.

OBJECTIVE: To determine the incidence and clinical effects of antibodies that develop during treatment with natalizumab. METHODS: In two randomized, double-blind, placebo-controlled studies (natalizumab safety and efficacy in relapsing remitting multiple sclerosis [MS, AFFIRM] and safety and efficacy of natalizumab in combination with interferon beta-1a [INF beta]1a] in patients with relapsing remitting MS [SENTINEL]) of patients with relapsing multiple sclerosis, blood samples were obtained at baseline and every 12 weeks to determine the presence of antibodies against natalizumab. Antibodies to natalizumab were measured using an ELISA. Patients were categorized as "transiently positive" if they had detectable antibodies (>or=0.5 microg/mL) at a single time point or "persistently positive" if they had antibodies at two or more time points >or=6 weeks apart. RESULTS: In the AFFIRM study, antibodies were detected in 57 of 625 (9%) of natalizumab-treated patients: Twenty (3%) were transiently positive and 37 (6%) were persistently positive. Persistently positive patients showed a loss of clinical efficacy as measured by disability progression (p

Natalizumab reduces visual loss in patients with relapsing multiple sclerosis.

OBJECTIVE: To examine the effects of natalizumab on low-contrast letter acuity as a prespecified tertiary endpoint in two randomized clinical trials and to evaluate the usefulness of low-contrast letter acuity testing as a candidate test of visual function in multiple sclerosis (MS). METHODS: AFFIRM and SENTINEL were randomized, double-blind, placebo-controlled, multicenter, phase 3 clinical trials of natalizumab in relapsing MS. Natalizumab was evaluated as monotherapy in AFFIRM and as add-on to interferon beta-1a in SENTINEL. Vision testing was performed at 100% contrast (visual acuity) and low-contrast (2.5% and 1.25%). RESULTS: The risk of clinically significant visual loss (predefined as a two-line worsening of acuity sustained over 12 weeks) at the lowest contrast level (1.25%) was reduced in the natalizumab treatment arms by 35% in AFFIRM (hazard ratio = 0.65; 95% CI: 0.47 to 0.90; p = 0.008) and by 28% in SENTINEL (hazard ratio = 0.72; 95% CI: 0.54 to 0.98; p = 0.038, Cox proportional hazards models). Mean changes in vision scores from baseline were also significantly different, reflecting worsening in non-natalizumab groups. CONCLUSIONS: Natalizumab reduces visual loss in patients with relapsing multiple sclerosis. Low-contrast acuity testing has the capacity to demonstrate treatment effects and is a strong candidate for assessment of visual outcomes in future multiple sclerosis trials.

Contrast letter acuity as a visual component for the Multiple Sclerosis Functional Composite.

BACKGROUND: Visual dysfunction is one of the most common causes of disability in multiple sclerosis (MS). The Multiple Sclerosis Functional Composite (MSFC), a new clinical trial outcome measure, does not currently include a test of visual function. OBJECTIVE: To examine contrast letter acuity as a candidate visual function test for the MSFC. METHODS: Binocular contrast letter acuity testing (Sloan charts) was performed in a subgroup of participants from the International Multiple Sclerosis Secondary Progressive Avonex Controlled Trial (IMPACT Substudy) and in MS patients and disease-free control subjects from a cross-sectional study of visual outcome measures (Multiple Sclerosis Vision Prospective cohort [MVP cohort]). High-contrast visual acuity was measured in both studies; MVP cohort participants underwent additional binocular testing for contrast sensitivity (Pelli-Robson chart), color vision (D-15 desaturated test), and visual field (Esterman test, Humphrey Field Analyzer II). RESULTS: Contrast letter acuity (Sloan charts, p < 0.0001, receiver operating characteristic curve analysis) and contrast sensitivity (Pelli-Robson chart, p = 0.003) best distinguished MS patients from disease-free control subjects in the MVP cohort. Correlations of Sloan chart scores with MSFC and Expanded Disability Statue Scale (EDSS) scores in both studies were significant and moderate in magnitude, demonstrating that Sloan chart scores reflect visual and neurologic dysfunction not entirely captured by the EDSS or MSFC. CONCLUSIONS: Among clinical measures, contrast letter acuity (Sloan charts) and contrast sensitivity (Pelli-Robson chart) demonstrate the greatest capacity to identify binocular visual dysfunction in MS. Sloan chart testing also captures unique aspects of neurologic dysfunction not captured by current EDSS or MSFC components, making it a strong candidate visual function test for the MSFC.

The utility of MRI in suspected MS: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.

Advancements in imaging technologies and newly evolving treatments offer the promise of more effective management strategies for MS. Until recently, confirmation of the diagnosis of MS has generally required the demonstration of clinical activity that is disseminated in both time and space. Nevertheless, with the advent of MRI techniques, occult disease activity can be demonstrated in 50 to 80% of patients at the time of the first clinical presentation. Prospective studies have shown that the presence of such lesions predicts future conversion to clinically definite (CD) MS. Indeed, in a young to middle-aged adult with a clinically isolated syndrome (CIS), once alternative diagnoses are excluded at baseline, the finding of three or more white matter lesions on a T2-weighted MRI scan (especially if one of these lesions is located in the periventricular region) is a very sensitive predictor (>80%) of the subsequent development of CDMS within the next 7 to 10 years. Moreover, the presence of two or more gadolinium (Gd)-enhancing lesions at baseline and the appearance of either new T2 lesions or new Gd enhancement on follow-up scans are also highly predictive of the subsequent development of CDMS in the near term. By contrast, normal results on MRI at the time of clinical presentation makes the future development of CDMS considerably less likely.

A novel population of B7-1+ T cells producing intracellular IL-4 is decreased in patients with multiple sclerosis.

We identified a novel population of human T cells, studied directly ex vivo, that co-express surface B7-1 and intracellular IL-4. These peripheral blood B7-1+/CD4+ T cells expressed cell surface molecules associated with differentiation including CD45RO and MHC class II, yet were CD69(-) and CD25(-). In short-term cultures, T cell receptor (TCR) cross-linking induced further IL-4 production with little IFN-gamma or TNF-alpha. In marked contrast, CD4+ T cells negative for B7-1 expressed intracellular IFN-gamma and high amounts of TNF-alpha but little IL-4 upon TCR cross-linking. The CD4+/B7-1+/IL-4-expressing T cells were of polyclonal origin based on their diverse TCR repertoire. To explore the biological significance of this B7-1+/IL-4+ T cell population and to assess its potential regulatory role in autoimmune disease, we examined whether these T cells isolated ex vivo were altered in subjects with multiple sclerosis (MS). While the frequency of B7-1+ T cells was enhanced in patients with MS as compared to normal subjects, there was a significant diminution of B7-1+/IL-4+ T cells in the patients. The decrease in these IL-4-producing T cells in patients with autoimmune disease is consistent with a possible role as immunoregulatory T cells.

Rationale for early treatment with interferon beta-1a in relapsing-remitting multiple sclerosis.

Disease-modifying therapies are now available for the treatment of relapsing-remitting multiple sclerosis (RR-MS). These drugs have transformed the management of RR-MS from simply treating symptomatic disease to providing effective but incomplete prophylaxis against further disease activity. Our ability to modify disease activity is limited to reducing exacerbations and delaying progression of disability. No intervention has yet been shown to reverse disability once it is established. To prevent disability, therapy should be initiated early in the course of the illness. The rationale for early treatment is as follows: (1) a high percentage of patients with clinically definite RR-MS progress from isolated attacks to neurologic impairment and then to disability within a short time; (2) survival in MS is directly related to disability, so delaying the onset of disability could be expected to influence survival; (3) interferon (IFN) beta-1a has been shown to slow the progression of disability when given to RR-MS patients with impairment or mild disability; and (4) magnetic resonance imaging studies indicate that MS patients frequently have evidence of central nervous system inflammation without overt clinical symptoms, and it has been postulated that treatment of subclinical disease as identified by magnetic resonance imaging may improve long-term outcome. IFN-beta reduces the number of new T2-weighted lesions, as well as the number and volume of gadolinium-enhanced lesions. Aggressive early treatment with IFN beta-1a is recommended, particularly for patients with risk factors suggesting an unfavorable prognosis.

An outbreak in 1965 of severe respiratory illness caused by the Legionnaires' disease bacterium.

In January 1977 an unsolved outbreak of infection at St. Elizabeth's Hospital (Washington, D.C.) that occurred in 1965 was linked with Legionnaires' disease. The link was made by fluorescent antibody testing with the bacterium isolated from tissues of persons with Legionnaires' disease in the 1976 outbreak in Philadelphia. In July and August 1965, an epidemic of severe respiratory disease characterized by abrupt onset of high fever, weakness, malaise, and nonproductive cough, frequently accompanied by radiographic evidence of pneumonia, affected at least 81 patients at St. Elizabeth's Hospital, a general psychiatric hospital. Fourteen (17%) of the affected patients died. Intensive epidemiologic and laboratory investigations in 1965 did not determine the etiology. The etiologic organism may have become airborne from sites of soil excavation.