William H. Stuart

Glatiramer acetate in primary progressive multiple sclerosis: Results of a multinational, multicenter, double-blind, placebo-controlled trial

To determine whether glatiramer acetate (GA) slows accumulation of disability in primary progressive multiple sclerosis.

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 β-1a [INFβ1a] 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 (≥0.5 μg/mL) at a single time point or “persistently positive” if they had antibodies at two or more time points ≥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 ≤ 0.05), relapse rate (p = 0.009), and MRI (p ≤ 0.05) compared with antibody-negative patients. In transiently positive patients, full efficacy was achieved after approximately 6 months of treatment, the time when patients were becoming antibody negative. The incidence of infusion-related adverse events was significantly higher in persistently positive patients. Results of SENTINEL were similar to AFFIRM, except with regard to sustained disability progression; differences between persistently positive and antibody-negative patients were not statistically significant. Conclusions: The incidence of persistent antibody positivity associated with natalizumab is 6%. Reduced clinical efficacy is apparent in persistently positive patients. Patients with a suboptimal clinical response or persistent infusion-related adverse events should be considered for antibody testing. GLOSSARY: BLQ = below the limit of quantification; EDSS = Expanded Disability Status Scale; Gd+ = gadolinium enhancing; IFNβ1a = interferon β-1a; MS = multiple sclerosis; MSFC = multiple sclerosis functional composite; OD = optical density.

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.

Health-related quality of life in multiple sclerosis: Effects of natalizumab

To report the relationship between disease activity and health‐related quality of life (HRQoL) in relapsing multiple sclerosis, and the impact of natalizumab.

The efficacy of natalizumab in patients with relapsing multiple sclerosis: subgroup analyses of AFFIRM and SENTINEL

The AFFIRM and SENTINEL studies showed that natalizumab was effective both as monotherapy and in combination with interferon beta (IFNβ)-1a in patients with relapsing multiple sclerosis (MS). Further analyses of AFFIRM and SENTINEL data were conducted to determine the efficacy of natalizumab in prespecified patient subgroups according to baseline characteristics: relapse history 1 year before randomization (1, 2, ≥ 3), Expanded Disability Status Scale score (≤ 3.5, > 3.5), number of T2 lesions (< 9, ≥ 9), presence of gadolinium-enhancing (Gd+) lesions (0, ≥ 1), age (< 40, ≥ 40) and gender (male, female). A post hoc analysis was conducted to determine the efficacy of natalizumab in patients with highly active disease (i. e., ≥ 2 relapses in the year before study entry and ≥ 1 Gd+ lesion at study entry). In both AFFIRM and SENTINEL studies natalizumab reduced the annualized relapse rates across all subgroups (except the small subgroups with < 9 baseline T2 lesions) over 2 years. In AFFIRM, natalizumab significantly reduced the risk of sustained disability progression in most subgroups. In SENTINEL, natalizumab significantly reduced the risk of sustained disability progression in the following subgroups: ≥ 9 T2 lesions at baseline, ≥ 1 Gd+ lesions at baseline, female patients and patients < 40 years of age. Natalizumab reduced the risk of disability progression by 64 % and relapse rate by 81 % in treatment- naive patients with highly active disease and by 58 % and 76 %, respectively, in patients with highly active disease despite IFNβ-1a treatment. These results indicate that natalizumab is effective in reducing disability progres- sion and relapses in patients with relapsing MS, particularly in patients with highly active disease.

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.

The PROMiSe trial: baseline data review and progress report

The PRO MiSe trial is a multinational, multicentre, double-blind, placebo -controlled trial evaluating the effects of glatiramer acetate treatment over 3 years in patients with primary progressive multiple sclerosis (PPMS). A total of 943 patients were enrolled, and all those remaining on-study had completed at least 24 months as of O ctober 2002. Baseline clinical and MRI character istics and select correlations are reported here. A total of 3.9% of patients exhibited confirmed relapse over 1904 patient-years of exposure, indicating success of efforts to exclude relapsing MS types. O f the 26.3% of patients who have prematurely withdrawn from the study, only 36% discontinued after meeting the study primary endpoint of disease progression. The progression rate in patients in the low Expanded Disability Status Scale (EDSS) stratum (3.0-5.0) observed thus far is markedly lower than the 50% annual progression rate estimate used for determining size and statistical power of the trial; progression was observed in 16.1% of patients with 12 months of study exposure. These early findings raise some concern about the ability of the trial to demonstrate a significant treatment effect, and suggest that the short-term natural history of PPMS may not be as aggressive as previously assumed.

A Multicenter, Open-Label, Phase II Study of the Immunogenicity and Safety of a New Prefilled Syringe (Liquid) Formulation of Avonex in Patients with Multiple Sclerosis

BACKGROUND A new liquid formulation of Avonex (interferon beta-1a [IFNbeta-1a]) in a prefilled syringe has been developed to make administration of the drug easier for patients with multiple sclerosis (MS). This formulation does not contain human serum albumin (HSA), often added to interferon (IFN) products for stabilization. However, formulation changes may alter the secondary, tertiary, and quaternary structures of IFNbeta products. These kinds of structural changes could lead to the formation of antibodies directed against IFNbeta. Some of these anti-IFN antibodies may neutralize the biologic activity of IFNbeta. OBJECTIVE This study was designed to determine the immunogenicity and safety of the new prefilled syringe (liquid) HSA-free formulation of Avonex in patients with relapsing MS. METHODS This was a multicenter, single-arm, open-label study. Patients with relapsing MS received liquid, HSA-free Avonex 30 microg by IM injection from a prefilled syringe once weekly for up to 24 months. Immunogenicity and safety were assessed every 3 months. Serum levels of neutralizing antibodies (NAbs) were measured at baseline and every 3 months using a 2-step enzyme-linked immunosorbent assay and antiviral cytopathic effect assay. RESULTS A total of 153 patients (121 women, 32 men; mean [SD] age, 39.6 [9.9] years; age range, 19.0-59.0 years) were enrolled in the study. Sera were available for analysis from 125 and 119 patients after 18 and 24 months of treatment, respectively. By 18 months, 1 patient (1%) had > or =2 consecutive titers of > or =20, a level at which the persistent presence of NAbs has been shown in some studies to have clinical consequences. By 24 months, 1 additional patient (total 2%) had > or =2 consecutive titers of > or =20. At 18 months, 5 patients (4%) had > or =1 NAb titer of > or =5; at 24 months, 6 patients (5%) had > or =1 NAb titer of > or =5. The safety profile of liquid Avonex was comparable to the lyophilized form containing HSA. CONCLUSIONS The prefilled syringe (liquid) HSA-free formulation of Avonex was well tolerated and showed a low level of immunogenicity. Over 24 months, 2% of patients developed persistent NAbs (> or =2 consecutive titers of > or =20).

Natalizumab plus interferon beta-1a reduces lesion formation in relapsing multiple sclerosis

The SENTINEL study showed that the addition of natalizumab improved outcomes for patients with relapsing multiple sclerosis (MS) who had experienced disease activity while receiving interferon beta-1a (IFNbeta-1a) alone. Previously unreported secondary and tertiary magnetic resonance imaging (MRI) measures are presented here. Patients received natalizumab 300 mg (n=589) or placebo (n=582) intravenously every 4 weeks plus IFNbeta-1a 30 microg intramuscularly once weekly. Annual MRI scans allowed comparison of a range of MRI end points versus baseline. Over 2 years, 67% of patients receiving natalizumab plus IFNbeta-1a remained free of new or enlarging T2-lesions compared with 30% of patients receiving IFNbeta-1a alone. The mean change from baseline in T2 lesion volume over 2 years decreased in patients receiving natalizumab plus IFNbeta-1a and increased in those receiving IFNbeta-1a alone (-277.5mm(3) versus 525.6mm(3); p<0.001). Compared with IFNbeta-1a alone, add-on natalizumab therapy resulted in a smaller increase in mean T1-hypointense lesion volume after 2 years (1821.3mm(3) versus 2210.5mm(3); p<0.001), a smaller mean number of new T1-hypointense lesions over 2 years (2.3 versus 4.1; p<0.001), and a slower rate of brain atrophy during the second year of therapy (-0.31% versus -0.40%; p=0.020). Natalizumab add-on therapy reduced gadolinium-enhancing, T1-hypointense, and T2 MRI lesion activity and slowed brain atrophy progression in patients with relapsing MS who experienced disease activity despite treatment with IFNbeta-1a alone.

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.