Frances Lynn

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.

MRI outcomes in a placebo-controlled trial of natalizumab in relapsing MS.

Background: In a 2-year, placebo-controlled trial (the Natalizumab Safety and Efficacy in Relapsing Remitting Multiple Sclerosis [AFFIRM] study), involving 942 patients with relapsing multiple sclerosis (MS), natalizumab significantly reduced the relapse rate by 68% and progression of sustained disability by 42% vs placebo. We report the effect of natalizumab on MRI measures from the AFFIRM study. Methods: The number and volume of gadolinium (Gd)-enhancing, new or enlarging T2-hyperintense, and new T1-hypointense lesions and brain parenchymal fraction were measured from annual scans obtained at baseline, 1 year, and 2 years. Results: Compared with placebo, natalizumab produced a 92% decrease in Gd-enhancing lesions (means 2.4 vs 0.2; p < 0.001), an 83% decrease in new or enlarging T2-hyperintense lesions (means 11.0 vs 1.9; p < 0.001), and a 76% decrease in new T1-hypointense lesions (means 4.6 vs 1.1; p < 0.001) over 2 years. Median T2-hyperintense lesion volume increased by 8.8% in the placebo group and decreased by 9.4% in the natalizumab group (p < 0.001); median T1-hypointense lesion volume decreased by 1.5% in the placebo group and decreased by 23.5% in the natalizumab group (p < 0.001). Brain atrophy was greater in year 1 and less in year 2 in natalizumab-treated patients. Conclusion: Natalizumab has a sustained effect in preventing the formation of new lesions in patients with relapsing multiple sclerosis.

Effect of plasma exchange in accelerating natalizumab clearance and restoring leukocyte function

Background: Accelerating the clearance of therapeutic monoclonal antibodies (mAbs) from the body may be useful to address uncommon but serious complications from treatment, such as progressive multifocal leukoencephalopathy (PML). Treatment of PML requires immune reconstitution. Plasma exchange (PLEX) may accelerate mAb clearance, restoring the function of inhibited proteins and increasing the number or function of leukocytes entering the CNS. We evaluated the efficacy of PLEX in accelerating natalizumab (a therapy for multiple sclerosis [MS] and Crohn disease) clearance and α4-integrin desaturation. Restoration of leukocyte transmigratory capacity was evaluated using an in vitro blood–brain barrier (ivBBB). Methods: Twelve patients with MS receiving natalizumab underwent three 1.5-volume PLEX sessions over 5 or 8 days. Natalizumab concentrations and α4-integrin saturation were assessed daily throughout PLEX and three times over the subsequent 2 weeks, comparing results with the same patients the previous month. Peripheral blood mononuclear cell (PBMC) migration (induced by the chemokine CCL2) across an ivBBB was assessed in a subset of six patients with and without PLEX. Results: Serum natalizumab concentrations were reduced by a mean of 92% from baseline to 1 week after three PLEX sessions (p < 0.001). Although average α4-integrin saturation was not reduced after PLEX, it was reduced to less than 50% when natalizumab concentrations were below 1 μg/mL. PBMC transmigratory capacity increased 2.2-fold after PLEX (p < 0.006). Conclusions: Plasma exchange (PLEX) accelerated clearance of natalizumab, and at natalizumab concentrations below 1 μg/mL, desaturation of α4-integrin was observed. Also, CCL2-induced leukocyte transmigration across an in vitro blood–brain barrier was increased after PLEX. Therefore, PLEX may be effective in restoring immune effector function in natalizumab-treated patients.

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.

Assessing disability progression with the Multiple Sclerosis Functional Composite

Background The initial Multiple Sclerosis Functional Composite (MSFC) proposal was a three-part composite of quantitative measures of ambulation, upper extremity function, and cognitive function expressed as a single composite Z-score. However, the clinical meaning of an MSFC Z-score change is not obvious. This study instead used MSFC component data to define a patient-specific disease progression event. Objective Evaluate a new method for analyzing disability progression using the MSFC. Methods MSFC progression was defined as worsening from baseline on scores of at least one MSFC component by 20% (MSFC Progression-20) or 15% (MSFC Progression-15), sustained for ≥3 months. Progression rates were determined using data from natalizumab clinical studies (Natalizumab Safety and Efficacy in Relapsing Remitting Multiple Sclerosis [AFFIRM] and Safety and Efficacy of Natalizumab in Combination With Interferon Beta-1a in Patients With Relapsing Remitting Multiple Sclerosis [SENTINEL]). Correlations between MSFC progression and other clinical measures were determined, as was sensitivity to treatment effects. Results Substantial numbers of patients met MSFC progression criteria, with MSFC Progression-15 being more sensitive than MSFC Progression-20, at both 1 and 2 years. MSFC Progression-20 and MSFC Progression-15 were related significantly to Expanded Disability Status Scale (EDSS) score change, relapse rate, and the SF-36 Physical Component Summary (PCS) score change. MSFC Progression-20 and MSFC Progression-15 at 1 year were predictive of EDSS progression at 2 years. Both MSFC progression end points demonstrated treatment effects in AFFIRM, and results were replicated in SENTINEL. Conclusion MSFC Progression-20 and MSFC Progression-15 are sensitive measures of disability progression; correlate with EDSS, relapse rates, and SF-36 PCS; and are capable of demonstrating therapeutic effects in randomized, controlled clinical studies.

Infusion-related hypersensitivity reactions during natalizumab treatment.

As with many biologic therapeutics, hypersensitivity reactions occurred during natalizumab treatment in the AFFIRM study.1 These hypersensitivity reactions included all events reported as hypersensitivity, allergic reaction, or anaphylactic/anaphylactoid by the investigator as well as any report of urticaria, allergic dermatitis, or hives. If a hypersensitivity reaction was observed, natalizumab was immediately discontinued and the patient was not retreated (per protocol). Twenty-five (4%) patients in the natalizumab-treated group experienced 27 hypersensitivity reactions (table); two patients were redosed after experiencing a hypersensitivity reaction; therefore, there were two protocol violations. Fifteen of these 27 hypersensitivity reactions occurred by the second infusion and an additional eight occurred between the third and seventh infusions. Eight hypersensitivity reactions were reported as serious adverse events (seven in the natalizumab group and one in the placebo group). The incidence of serious systemic hypersensitivity reactions, classified as anaphylactoid or anaphylactic reactions, was <1%. Seventeen of the 25 (68%) natalizumab patients with hypersensitivity reactions, which included all the patients with serious systemic reactions, were persistently positive for antibodies to natalizumab. In the SENTINEL study, 11 (1.9%) natalizumab-treated patients experienced hypersensitivity reactions; however, no anaphylactic or anaphylactoid reactions were observed.2 View this table: Table Hypersensitivity reactions in the AFFIRM study Treatment of hypersensitivity reactions was at the discretion of …

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.